Merge remote-tracking branch 'common/android-4.4' into android-4.4.y

15 files changed, 2211 insertions, 206 deletions

diff --git a/drivers/input/keyboard/goldfish_events.c b/drivers/input/keyboard/goldfish_events.c
index 907e4e278fce..c877e56a9bd5 100644
--- a/drivers/input/keyboard/goldfish_events.c
+++ b/drivers/input/keyboard/goldfish_events.c
@@ -17,11 +17,15 @@
 #include <linux/interrupt.h>
 #include <linux/types.h>
 #include <linux/input.h>
+#include <linux/input/mt.h>
 #include <linux/kernel.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/irq.h>
 #include <linux/io.h>
+#include <linux/acpi.h>
+
+#define GOLDFISH_MAX_FINGERS 5
 
 enum {
 	REG_READ        = 0x00,
@@ -51,7 +55,21 @@ static irqreturn_t events_interrupt(int irq, void *dev_id)
 	value = __raw_readl(edev->addr + REG_READ);
 
 	input_event(edev->input, type, code, value);
-	input_sync(edev->input);
+	// Send an extra (EV_SYN, SYN_REPORT, 0x0) event
+	// if a key was pressed. Some keyboard device
+        // drivers may only send the EV_KEY event and
+        // not EV_SYN.
+        // Note that sending an extra SYN_REPORT is not
+        // necessary nor correct protocol with other
+        // devices such as touchscreens, which will send
+        // their own SYN_REPORT's when sufficient event
+        // information has been collected (e.g., for
+        // touchscreens, when pressure and X/Y coordinates
+	// have been received). Hence, we will only send
+	// this extra SYN_REPORT if type == EV_KEY.
+	if (type == EV_KEY) {
+		input_sync(edev->input);
+	}
 	return IRQ_HANDLED;
 }
 
@@ -153,6 +171,15 @@ static int events_probe(struct platform_device *pdev)
 
 	input_dev->name = edev->name;
 	input_dev->id.bustype = BUS_HOST;
+	// Set the Goldfish Device to be multi-touch.
+	// In the Ranchu kernel, there is multi-touch-specific
+	// code for handling ABS_MT_SLOT events.
+	// See drivers/input/input.c:input_handle_abs_event.
+	// If we do not issue input_mt_init_slots,
+        // the kernel will filter out needed ABS_MT_SLOT
+        // events when we touch the screen in more than one place,
+        // preventing multi-touch with more than one finger from working.
+	input_mt_init_slots(input_dev, GOLDFISH_MAX_FINGERS, 0);
 
 	events_import_bits(edev, input_dev->evbit, EV_SYN, EV_MAX);
 	events_import_bits(edev, input_dev->keybit, EV_KEY, KEY_MAX);
@@ -178,10 +205,26 @@ static int events_probe(struct platform_device *pdev)
 	return 0;
 }
 
+static const struct of_device_id goldfish_events_of_match[] = {
+	{ .compatible = "google,goldfish-events-keypad", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, goldfish_events_of_match);
+
+#ifdef CONFIG_ACPI
+static const struct acpi_device_id goldfish_events_acpi_match[] = {
+	{ "GFSH0002", 0 },
+	{ },
+};
+MODULE_DEVICE_TABLE(acpi, goldfish_events_acpi_match);
+#endif
+
 static struct platform_driver events_driver = {
 	.probe	= events_probe,
 	.driver	= {
 		.name	= "goldfish_events",
+		.of_match_table = goldfish_events_of_match,
+		.acpi_match_table = ACPI_PTR(goldfish_events_acpi_match),
 	},
 };
 
diff --git a/drivers/platform/goldfish/Makefile b/drivers/platform/goldfish/Makefile
index d3487125838c..e53ae2fc717b 100644
--- a/drivers/platform/goldfish/Makefile
+++ b/drivers/platform/goldfish/Makefile
@@ -2,4 +2,4 @@
 # Makefile for Goldfish platform specific drivers
 #
 obj-$(CONFIG_GOLDFISH_BUS)	+= pdev_bus.o
-obj-$(CONFIG_GOLDFISH_PIPE)	+= goldfish_pipe.o
+obj-$(CONFIG_GOLDFISH_PIPE)	+= goldfish_pipe.o goldfish_pipe_v2.o
diff --git a/drivers/platform/goldfish/goldfish_pipe.c b/drivers/platform/goldfish/goldfish_pipe.c
index 3215a33cf4fe..fd1452e28352 100644
--- a/drivers/platform/goldfish/goldfish_pipe.c
+++ b/drivers/platform/goldfish/goldfish_pipe.c
@@ -15,51 +15,11 @@
  *
  */
 
-/* This source file contains the implementation of a special device driver
- * that intends to provide a *very* fast communication channel between the
- * guest system and the QEMU emulator.
- *
- * Usage from the guest is simply the following (error handling simplified):
- *
- *    int  fd = open("/dev/qemu_pipe",O_RDWR);
- *    .... write() or read() through the pipe.
- *
- * This driver doesn't deal with the exact protocol used during the session.
- * It is intended to be as simple as something like:
- *
- *    // do this _just_ after opening the fd to connect to a specific
- *    // emulator service.
- *    const char*  msg = "<pipename>";
- *    if (write(fd, msg, strlen(msg)+1) < 0) {
- *       ... could not connect to <pipename> service
- *       close(fd);
- *    }
- *
- *    // after this, simply read() and write() to communicate with the
- *    // service. Exact protocol details left as an exercise to the reader.
- *
- * This driver is very fast because it doesn't copy any data through
- * intermediate buffers, since the emulator is capable of translating
- * guest user addresses into host ones.
- *
- * Note that we must however ensure that each user page involved in the
- * exchange is properly mapped during a transfer.
+/* This source file contains the implementation of the legacy version of
+ * a goldfish pipe device driver. See goldfish_pipe_v2.c for the current
+ * version.
  */
-
-#include <linux/module.h>
-#include <linux/interrupt.h>
-#include <linux/kernel.h>
-#include <linux/spinlock.h>
-#include <linux/miscdevice.h>
-#include <linux/platform_device.h>
-#include <linux/poll.h>
-#include <linux/sched.h>
-#include <linux/bitops.h>
-#include <linux/slab.h>
-#include <linux/io.h>
-#include <linux/goldfish.h>
-#include <linux/mm.h>
-#include <linux/acpi.h>
+#include "goldfish_pipe.h"
 
 /*
  * IMPORTANT: The following constants must match the ones used and defined
@@ -109,29 +69,15 @@
 #define PIPE_WAKE_READ         (1 << 1)  /* pipe can now be read from */
 #define PIPE_WAKE_WRITE        (1 << 2)  /* pipe can now be written to */
 
-struct access_params {
-	unsigned long channel;
-	u32 size;
-	unsigned long address;
-	u32 cmd;
-	u32 result;
-	/* reserved for future extension */
-	u32 flags;
-};
+#define MAX_PAGES_TO_GRAB 32
 
-/* The global driver data. Holds a reference to the i/o page used to
- * communicate with the emulator, and a wake queue for blocked tasks
- * waiting to be awoken.
- */
-struct goldfish_pipe_dev {
-	spinlock_t lock;
-	unsigned char __iomem *base;
-	struct access_params *aps;
-	int irq;
-	u32 version;
-};
+#define DEBUG 0
 
-static struct goldfish_pipe_dev   pipe_dev[1];
+#if DEBUG
+#define DPRINT(...) { printk(KERN_ERR __VA_ARGS__); }
+#else
+#define DPRINT(...)
+#endif
 
 /* This data type models a given pipe instance */
 struct goldfish_pipe {
@@ -141,6 +87,15 @@ struct goldfish_pipe {
 	wait_queue_head_t wake_queue;
 };
 
+struct access_params {
+	unsigned long channel;
+	u32 size;
+	unsigned long address;
+	u32 cmd;
+	u32 result;
+	/* reserved for future extension */
+	u32 flags;
+};
 
 /* Bit flags for the 'flags' field */
 enum {
@@ -231,8 +186,10 @@ static int setup_access_params_addr(struct platform_device *pdev,
 	if (valid_batchbuffer_addr(dev, aps)) {
 		dev->aps = aps;
 		return 0;
-	} else
+	} else {
+		devm_kfree(&pdev->dev, aps);
 		return -1;
+	}
 }
 
 /* A value that will not be set by qemu emulator */
@@ -269,6 +226,7 @@ static ssize_t goldfish_pipe_read_write(struct file *filp, char __user *buffer,
 	struct goldfish_pipe *pipe = filp->private_data;
 	struct goldfish_pipe_dev *dev = pipe->dev;
 	unsigned long address, address_end;
+	struct page* pages[MAX_PAGES_TO_GRAB] = {};
 	int count = 0, ret = -EINVAL;
 
 	/* If the emulator already closed the pipe, no need to go further */
@@ -292,45 +250,62 @@ static ssize_t goldfish_pipe_read_write(struct file *filp, char __user *buffer,
 	address_end = address + bufflen;
 
 	while (address < address_end) {
-		unsigned long  page_end = (address & PAGE_MASK) + PAGE_SIZE;
-		unsigned long  next     = page_end < address_end ? page_end
-								 : address_end;
-		unsigned long  avail    = next - address;
-		int status, wakeBit;
-
-		struct page *page;
-
-		/* Either vaddr or paddr depending on the device version */
-		unsigned long xaddr;
+		unsigned long page_end = (address & PAGE_MASK) + PAGE_SIZE;
+		unsigned long next, avail;
+		int status, wakeBit, page_i, num_contiguous_pages;
+		long first_page, last_page, requested_pages;
+		unsigned long xaddr, xaddr_prev, xaddr_i;
 
 		/*
-		 * We grab the pages on a page-by-page basis in case user
-		 * space gives us a potentially huge buffer but the read only
-		 * returns a small amount, then there's no need to pin that
-		 * much memory to the process.
+		 * Attempt to grab multiple physically contiguous pages.
 		 */
-		down_read(&current->mm->mmap_sem);
-		ret = get_user_pages(current, current->mm, address, 1,
-				     !is_write, 0, &page, NULL);
-		up_read(&current->mm->mmap_sem);
-		if (ret < 0)
+		first_page = address & PAGE_MASK;
+		last_page = (address_end - 1) & PAGE_MASK;
+		requested_pages = ((last_page - first_page) >> PAGE_SHIFT) + 1;
+		if (requested_pages > MAX_PAGES_TO_GRAB) {
+			requested_pages = MAX_PAGES_TO_GRAB;
+		}
+		ret = get_user_pages_fast(first_page, requested_pages,
+				!is_write, pages);
+
+		DPRINT("%s: requested pages: %d %d %p\n", __FUNCTION__,
+			ret, requested_pages, first_page);
+		if (ret == 0) {
+			DPRINT("%s: error: (requested pages == 0) (wanted %d)\n",
+					__FUNCTION__, requested_pages);
+			mutex_unlock(&pipe->lock);
 			return ret;
+		}
+		if (ret < 0) {
+			DPRINT("%s: (requested pages < 0) %d \n",
+				 	__FUNCTION__, requested_pages);
+			mutex_unlock(&pipe->lock);
+			return ret;
+		}
 
-		if (dev->version) {
-			/* Device version 1 or newer (qemu-android) expects the
-			 * physical address. */
-			xaddr = page_to_phys(page) | (address & ~PAGE_MASK);
-		} else {
-			/* Device version 0 (classic emulator) expects the
-			 * virtual address. */
-			xaddr = address;
+		xaddr = page_to_phys(pages[0]) | (address & ~PAGE_MASK);
+		xaddr_prev = xaddr;
+		num_contiguous_pages = ret == 0 ? 0 : 1;
+		for (page_i = 1; page_i < ret; page_i++) {
+			xaddr_i = page_to_phys(pages[page_i]) | (address & ~PAGE_MASK);
+			if (xaddr_i == xaddr_prev + PAGE_SIZE) {
+				page_end += PAGE_SIZE;
+				xaddr_prev = xaddr_i;
+				num_contiguous_pages++;
+			} else {
+				DPRINT("%s: discontinuous page boundary: %d pages instead\n",
+						__FUNCTION__, page_i);
+				break;
+			}
 		}
+		next = page_end < address_end ? page_end : address_end;
+		avail = next - address;
 
 		/* Now, try to transfer the bytes in the current page */
 		spin_lock_irqsave(&dev->lock, irq_flags);
 		if (access_with_param(dev,
-				      is_write ? CMD_WRITE_BUFFER : CMD_READ_BUFFER,
-				      xaddr, avail, pipe, &status)) {
+					is_write ? CMD_WRITE_BUFFER : CMD_READ_BUFFER,
+					xaddr, avail, pipe, &status)) {
 			gf_write_ptr(pipe, dev->base + PIPE_REG_CHANNEL,
 				     dev->base + PIPE_REG_CHANNEL_HIGH);
 			writel(avail, dev->base + PIPE_REG_SIZE);
@@ -343,9 +318,13 @@ static ssize_t goldfish_pipe_read_write(struct file *filp, char __user *buffer,
 		}
 		spin_unlock_irqrestore(&dev->lock, irq_flags);
 
-		if (status > 0 && !is_write)
-			set_page_dirty(page);
-		put_page(page);
+		for (page_i = 0; page_i < ret; page_i++) {
+			if (status > 0 && !is_write &&
+				page_i < num_contiguous_pages) {
+				set_page_dirty(pages[page_i]);
+			}
+			put_page(pages[page_i]);
+		}
 
 		if (status > 0) { /* Correct transfer */
 			count += status;
@@ -367,7 +346,7 @@ static ssize_t goldfish_pipe_read_write(struct file *filp, char __user *buffer,
 			 */
 			if (status != PIPE_ERROR_AGAIN)
 				pr_info_ratelimited("goldfish_pipe: backend returned error %d on %s\n",
-					    status, is_write ? "write" : "read");
+						status, is_write ? "write" : "read");
 			ret = 0;
 			break;
 		}
@@ -377,7 +356,7 @@ static ssize_t goldfish_pipe_read_write(struct file *filp, char __user *buffer,
 		 * non-blocking mode, just return the error code.
 		 */
 		if (status != PIPE_ERROR_AGAIN ||
-			(filp->f_flags & O_NONBLOCK) != 0) {
+				(filp->f_flags & O_NONBLOCK) != 0) {
 			ret = goldfish_pipe_error_convert(status);
 			break;
 		}
@@ -391,7 +370,7 @@ static ssize_t goldfish_pipe_read_write(struct file *filp, char __user *buffer,
 
 		/* Tell the emulator we're going to wait for a wake event */
 		goldfish_cmd(pipe,
-			     is_write ? CMD_WAKE_ON_WRITE : CMD_WAKE_ON_READ);
+				is_write ? CMD_WAKE_ON_WRITE : CMD_WAKE_ON_READ);
 
 		/* Unlock the pipe, then wait for the wake signal */
 		mutex_unlock(&pipe->lock);
@@ -399,22 +378,16 @@ static ssize_t goldfish_pipe_read_write(struct file *filp, char __user *buffer,
 		while (test_bit(wakeBit, &pipe->flags)) {
 			if (wait_event_interruptible(
 					pipe->wake_queue,
-					!test_bit(wakeBit, &pipe->flags))) {
-				ret = -ERESTARTSYS;
-				break;
-			}
+					!test_bit(wakeBit, &pipe->flags)))
+				return -ERESTARTSYS;
 
-			if (test_bit(BIT_CLOSED_ON_HOST, &pipe->flags)) {
-				ret = -EIO;
-				break;
-			}
+			if (test_bit(BIT_CLOSED_ON_HOST, &pipe->flags))
+				return -EIO;
 		}
 
 		/* Try to re-acquire the lock */
-		if (mutex_lock_interruptible(&pipe->lock)) {
-			ret = -ERESTARTSYS;
-			break;
-		}
+		if (mutex_lock_interruptible(&pipe->lock))
+			return -ERESTARTSYS;
 	}
 	mutex_unlock(&pipe->lock);
 
@@ -543,6 +516,8 @@ static int goldfish_pipe_open(struct inode *inode, struct file *file)
 
 	pipe->dev = dev;
 	mutex_init(&pipe->lock);
+	DPRINT("%s: call. pipe_dev pipe_dev=0x%lx new_pipe_addr=0x%lx file=0x%lx\n", __FUNCTION__, pipe_dev, pipe, file);
+	// spin lock init, write head of list, i guess
 	init_waitqueue_head(&pipe->wake_queue);
 
 	/*
@@ -565,6 +540,7 @@ static int goldfish_pipe_release(struct inode *inode, struct file *filp)
 {
 	struct goldfish_pipe *pipe = filp->private_data;
 
+	DPRINT("%s: call. pipe=0x%lx file=0x%lx\n", __FUNCTION__, pipe, filp);
 	/* The guest is closing the channel, so tell the emulator right now */
 	goldfish_cmd(pipe, CMD_CLOSE);
 	kfree(pipe);
@@ -581,96 +557,33 @@ static const struct file_operations goldfish_pipe_fops = {
 	.release = goldfish_pipe_release,
 };
 
-static struct miscdevice goldfish_pipe_device = {
+static struct miscdevice goldfish_pipe_dev = {
 	.minor = MISC_DYNAMIC_MINOR,
 	.name = "goldfish_pipe",
 	.fops = &goldfish_pipe_fops,
 };
 
-static int goldfish_pipe_probe(struct platform_device *pdev)
+int goldfish_pipe_device_init_v1(struct platform_device *pdev)
 {
-	int err;
-	struct resource *r;
 	struct goldfish_pipe_dev *dev = pipe_dev;
-
-	/* not thread safe, but this should not happen */
-	WARN_ON(dev->base != NULL);
-
-	spin_lock_init(&dev->lock);
-
-	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	if (r == NULL || resource_size(r) < PAGE_SIZE) {
-		dev_err(&pdev->dev, "can't allocate i/o page\n");
-		return -EINVAL;
-	}
-	dev->base = devm_ioremap(&pdev->dev, r->start, PAGE_SIZE);
-	if (dev->base == NULL) {
-		dev_err(&pdev->dev, "ioremap failed\n");
-		return -EINVAL;
-	}
-
-	r = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
-	if (r == NULL) {
-		err = -EINVAL;
-		goto error;
-	}
-	dev->irq = r->start;
-
-	err = devm_request_irq(&pdev->dev, dev->irq, goldfish_pipe_interrupt,
+	int err = devm_request_irq(&pdev->dev, dev->irq, goldfish_pipe_interrupt,
 				IRQF_SHARED, "goldfish_pipe", dev);
 	if (err) {
-		dev_err(&pdev->dev, "unable to allocate IRQ\n");
-		goto error;
+		dev_err(&pdev->dev, "unable to allocate IRQ for v1\n");
+		return err;
 	}
 
-	err = misc_register(&goldfish_pipe_device);
+	err = misc_register(&goldfish_pipe_dev);
 	if (err) {
-		dev_err(&pdev->dev, "unable to register device\n");
-		goto error;
+		dev_err(&pdev->dev, "unable to register v1 device\n");
+		return err;
 	}
-	setup_access_params_addr(pdev, dev);
 
-	/* Although the pipe device in the classic Android emulator does not
-	 * recognize the 'version' register, it won't treat this as an error
-	 * either and will simply return 0, which is fine. */
-	dev->version = readl(dev->base + PIPE_REG_VERSION);
+	setup_access_params_addr(pdev, dev);
 	return 0;
-
-error:
-	dev->base = NULL;
-	return err;
 }
 
-static int goldfish_pipe_remove(struct platform_device *pdev)
+void goldfish_pipe_device_deinit_v1(struct platform_device *pdev)
 {
-	struct goldfish_pipe_dev *dev = pipe_dev;
-	misc_deregister(&goldfish_pipe_device);
-	dev->base = NULL;
-	return 0;
+    misc_deregister(&goldfish_pipe_dev);
 }
-
-static const struct acpi_device_id goldfish_pipe_acpi_match[] = {
-	{ "GFSH0003", 0 },
-	{ },
-};
-MODULE_DEVICE_TABLE(acpi, goldfish_pipe_acpi_match);
-
-static const struct of_device_id goldfish_pipe_of_match[] = {
-	{ .compatible = "generic,android-pipe", },
-	{},
-};
-MODULE_DEVICE_TABLE(of, goldfish_pipe_of_match);
-
-static struct platform_driver goldfish_pipe = {
-	.probe = goldfish_pipe_probe,
-	.remove = goldfish_pipe_remove,
-	.driver = {
-		.name = "goldfish_pipe",
-		.of_match_table = goldfish_pipe_of_match,
-		.acpi_match_table = ACPI_PTR(goldfish_pipe_acpi_match),
-	}
-};
-
-module_platform_driver(goldfish_pipe);
-MODULE_AUTHOR("David Turner <digit@google.com>");
-MODULE_LICENSE("GPL");
diff --git a/drivers/platform/goldfish/goldfish_pipe.h b/drivers/platform/goldfish/goldfish_pipe.h
new file mode 100644
index 000000000000..9b75a51dba24
--- /dev/null
+++ b/drivers/platform/goldfish/goldfish_pipe.h
@@ -0,0 +1,91 @@
+/*
+ * Copyright (C) 2016 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+#ifndef GOLDFISH_PIPE_H
+#define GOLDFISH_PIPE_H
+
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/spinlock.h>
+#include <linux/miscdevice.h>
+#include <linux/platform_device.h>
+#include <linux/poll.h>
+#include <linux/sched.h>
+#include <linux/bitops.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/goldfish.h>
+#include <linux/mm.h>
+#include <linux/acpi.h>
+
+
+/* Initialize the legacy version of the pipe device driver */
+int goldfish_pipe_device_init_v1(struct platform_device *pdev);
+
+/* Deinitialize the legacy version of the pipe device driver */
+void goldfish_pipe_device_deinit_v1(struct platform_device *pdev);
+
+/* Forward declarations for the device struct */
+struct goldfish_pipe;
+struct goldfish_pipe_device_buffers;
+
+/* The global driver data. Holds a reference to the i/o page used to
+ * communicate with the emulator, and a wake queue for blocked tasks
+ * waiting to be awoken.
+ */
+struct goldfish_pipe_dev {
+	/*
+	 * Global device spinlock. Protects the following members:
+	 *  - pipes, pipes_capacity
+	 *  - [*pipes, *pipes + pipes_capacity) - array data
+	 *  - first_signalled_pipe,
+	 *      goldfish_pipe::prev_signalled,
+	 *      goldfish_pipe::next_signalled,
+	 *      goldfish_pipe::signalled_flags - all singnalled-related fields,
+	 *                                       in all allocated pipes
+	 *  - open_command_params - PIPE_CMD_OPEN-related buffers
+	 *
+	 * It looks like a lot of different fields, but the trick is that the only
+	 * operation that happens often is the signalled pipes array manipulation.
+	 * That's why it's OK for now to keep the rest of the fields under the same
+	 * lock. If we notice too much contention because of PIPE_CMD_OPEN,
+	 * then we should add a separate lock there.
+	 */
+	spinlock_t lock;
+
+	/*
+	 * Array of the pipes of |pipes_capacity| elements,
+	 * indexed by goldfish_pipe::id
+	 */
+	struct goldfish_pipe **pipes;
+	u32 pipes_capacity;
+
+	/* Pointers to the buffers host uses for interaction with this driver */
+	struct goldfish_pipe_dev_buffers *buffers;
+
+	/* Head of a doubly linked list of signalled pipes */
+	struct goldfish_pipe *first_signalled_pipe;
+
+	/* Some device-specific data */
+	int irq;
+	int version;
+	unsigned char __iomem *base;
+
+	/* v1-specific access parameters */
+	struct access_params *aps;
+};
+
+extern struct goldfish_pipe_dev pipe_dev[1];
+
+#endif /* GOLDFISH_PIPE_H */
diff --git a/drivers/platform/goldfish/goldfish_pipe_v2.c b/drivers/platform/goldfish/goldfish_pipe_v2.c
new file mode 100644
index 000000000000..ad373ed36555
--- /dev/null
+++ b/drivers/platform/goldfish/goldfish_pipe_v2.c
@@ -0,0 +1,889 @@
+/*
+ * Copyright (C) 2012 Intel, Inc.
+ * Copyright (C) 2013 Intel, Inc.
+ * Copyright (C) 2014 Linaro Limited
+ * Copyright (C) 2011-2016 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+/* This source file contains the implementation of a special device driver
+ * that intends to provide a *very* fast communication channel between the
+ * guest system and the QEMU emulator.
+ *
+ * Usage from the guest is simply the following (error handling simplified):
+ *
+ *    int  fd = open("/dev/qemu_pipe",O_RDWR);
+ *    .... write() or read() through the pipe.
+ *
+ * This driver doesn't deal with the exact protocol used during the session.
+ * It is intended to be as simple as something like:
+ *
+ *    // do this _just_ after opening the fd to connect to a specific
+ *    // emulator service.
+ *    const char*  msg = "<pipename>";
+ *    if (write(fd, msg, strlen(msg)+1) < 0) {
+ *       ... could not connect to <pipename> service
+ *       close(fd);
+ *    }
+ *
+ *    // after this, simply read() and write() to communicate with the
+ *    // service. Exact protocol details left as an exercise to the reader.
+ *
+ * This driver is very fast because it doesn't copy any data through
+ * intermediate buffers, since the emulator is capable of translating
+ * guest user addresses into host ones.
+ *
+ * Note that we must however ensure that each user page involved in the
+ * exchange is properly mapped during a transfer.
+ */
+
+#include "goldfish_pipe.h"
+
+
+/*
+ * Update this when something changes in the driver's behavior so the host
+ * can benefit from knowing it
+ */
+enum {
+	PIPE_DRIVER_VERSION = 2,
+	PIPE_CURRENT_DEVICE_VERSION = 2
+};
+
+/*
+ * IMPORTANT: The following constants must match the ones used and defined
+ * in external/qemu/hw/goldfish_pipe.c in the Android source tree.
+ */
+
+/* List of bitflags returned in status of CMD_POLL command */
+enum PipePollFlags {
+	PIPE_POLL_IN	= 1 << 0,
+	PIPE_POLL_OUT	= 1 << 1,
+	PIPE_POLL_HUP	= 1 << 2
+};
+
+/* Possible status values used to signal errors - see goldfish_pipe_error_convert */
+enum PipeErrors {
+	PIPE_ERROR_INVAL  = -1,
+	PIPE_ERROR_AGAIN  = -2,
+	PIPE_ERROR_NOMEM  = -3,
+	PIPE_ERROR_IO     = -4
+};
+
+/* Bit-flags used to signal events from the emulator */
+enum PipeWakeFlags {
+	PIPE_WAKE_CLOSED = 1 << 0,  /* emulator closed pipe */
+	PIPE_WAKE_READ   = 1 << 1,  /* pipe can now be read from */
+	PIPE_WAKE_WRITE  = 1 << 2  /* pipe can now be written to */
+};
+
+/* Bit flags for the 'flags' field */
+enum PipeFlagsBits {
+	BIT_CLOSED_ON_HOST = 0,  /* pipe closed by host */
+	BIT_WAKE_ON_WRITE  = 1,  /* want to be woken on writes */
+	BIT_WAKE_ON_READ   = 2,  /* want to be woken on reads */
+};
+
+enum PipeRegs {
+	PIPE_REG_CMD = 0,
+
+	PIPE_REG_SIGNAL_BUFFER_HIGH = 4,
+	PIPE_REG_SIGNAL_BUFFER = 8,
+	PIPE_REG_SIGNAL_BUFFER_COUNT = 12,
+
+	PIPE_REG_OPEN_BUFFER_HIGH = 20,
+	PIPE_REG_OPEN_BUFFER = 24,
+
+	PIPE_REG_VERSION = 36,
+
+	PIPE_REG_GET_SIGNALLED = 48,
+};
+
+enum PipeCmdCode {
+	PIPE_CMD_OPEN = 1,	/* to be used by the pipe device itself */
+	PIPE_CMD_CLOSE,
+	PIPE_CMD_POLL,
+	PIPE_CMD_WRITE,
+	PIPE_CMD_WAKE_ON_WRITE,
+	PIPE_CMD_READ,
+	PIPE_CMD_WAKE_ON_READ,
+
+	/*
+	 * TODO(zyy): implement a deferred read/write execution to allow parallel
+	 *  processing of pipe operations on the host.
+	*/
+	PIPE_CMD_WAKE_ON_DONE_IO,
+};
+
+enum {
+	MAX_BUFFERS_PER_COMMAND = 336,
+	MAX_SIGNALLED_PIPES = 64,
+	INITIAL_PIPES_CAPACITY = 64
+};
+
+struct goldfish_pipe_dev;
+struct goldfish_pipe;
+struct goldfish_pipe_command;
+
+/* A per-pipe command structure, shared with the host */
+struct goldfish_pipe_command {
+	s32 cmd;		/* PipeCmdCode, guest -> host */
+	s32 id;			/* pipe id, guest -> host */
+	s32 status;		/* command execution status, host -> guest */
+	s32 reserved;	/* to pad to 64-bit boundary */
+	union {
+		/* Parameters for PIPE_CMD_{READ,WRITE} */
+		struct {
+			u32 buffers_count;					/* number of buffers, guest -> host */
+			s32 consumed_size;					/* number of consumed bytes, host -> guest */
+			u64 ptrs[MAX_BUFFERS_PER_COMMAND]; 	/* buffer pointers, guest -> host */
+			u32 sizes[MAX_BUFFERS_PER_COMMAND];	/* buffer sizes, guest -> host */
+		} rw_params;
+	};
+};
+
+/* A single signalled pipe information */
+struct signalled_pipe_buffer {
+	u32 id;
+	u32 flags;
+};
+
+/* Parameters for the PIPE_CMD_OPEN command */
+struct open_command_param {
+	u64 command_buffer_ptr;
+	u32 rw_params_max_count;
+};
+
+/* Device-level set of buffers shared with the host */
+struct goldfish_pipe_dev_buffers {
+	struct open_command_param open_command_params;
+	struct signalled_pipe_buffer signalled_pipe_buffers[MAX_SIGNALLED_PIPES];
+};
+
+/* This data type models a given pipe instance */
+struct goldfish_pipe {
+	u32 id;							/* pipe ID - index into goldfish_pipe_dev::pipes array */
+	unsigned long flags;			/* The wake flags pipe is waiting for
+									 * Note: not protected with any lock, uses atomic operations
+									 *  and barriers to make it thread-safe.
+									 */
+	unsigned long signalled_flags;	/* wake flags host have signalled,
+									 *  - protected by goldfish_pipe_dev::lock */
+
+	struct goldfish_pipe_command *command_buffer;	/* A pointer to command buffer */
+
+	/* doubly linked list of signalled pipes, protected by goldfish_pipe_dev::lock */
+	struct goldfish_pipe *prev_signalled;
+	struct goldfish_pipe *next_signalled;
+
+	/*
+	 * A pipe's own lock. Protects the following:
+	 *  - *command_buffer - makes sure a command can safely write its parameters
+	 *    to the host and read the results back.
+	 */
+	struct mutex lock;
+
+	wait_queue_head_t wake_queue;	/* A wake queue for sleeping until host signals an event */
+	struct goldfish_pipe_dev *dev;	/* Pointer to the parent goldfish_pipe_dev instance */
+};
+
+struct goldfish_pipe_dev pipe_dev[1] = {};
+
+static int goldfish_cmd_locked(struct goldfish_pipe *pipe, enum PipeCmdCode cmd)
+{
+	pipe->command_buffer->cmd = cmd;
+	pipe->command_buffer->status = PIPE_ERROR_INVAL;	/* failure by default */
+	writel(pipe->id, pipe->dev->base + PIPE_REG_CMD);
+	return pipe->command_buffer->status;
+}
+
+static int goldfish_cmd(struct goldfish_pipe *pipe, enum PipeCmdCode cmd)
+{
+	int status;
+	if (mutex_lock_interruptible(&pipe->lock))
+		return PIPE_ERROR_IO;
+	status = goldfish_cmd_locked(pipe, cmd);
+	mutex_unlock(&pipe->lock);
+	return status;
+}
+
+/*
+ * This function converts an error code returned by the emulator through
+ * the PIPE_REG_STATUS i/o register into a valid negative errno value.
+ */
+static int goldfish_pipe_error_convert(int status)
+{
+	switch (status) {
+	case PIPE_ERROR_AGAIN:
+		return -EAGAIN;
+	case PIPE_ERROR_NOMEM:
+		return -ENOMEM;
+	case PIPE_ERROR_IO:
+		return -EIO;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int pin_user_pages(unsigned long first_page, unsigned long last_page,
+	unsigned last_page_size, int is_write,
+	struct page *pages[MAX_BUFFERS_PER_COMMAND], unsigned *iter_last_page_size)
+{
+	int ret;
+	int requested_pages = ((last_page - first_page) >> PAGE_SHIFT) + 1;
+	if (requested_pages > MAX_BUFFERS_PER_COMMAND) {
+		requested_pages = MAX_BUFFERS_PER_COMMAND;
+		*iter_last_page_size = PAGE_SIZE;
+	} else {
+		*iter_last_page_size = last_page_size;
+	}
+
+	ret = get_user_pages_fast(
+			first_page, requested_pages, !is_write, pages);
+	if (ret <= 0)
+		return -EFAULT;
+	if (ret < requested_pages)
+		*iter_last_page_size = PAGE_SIZE;
+	return ret;
+
+}
+
+static void release_user_pages(struct page **pages, int pages_count,
+	int is_write, s32 consumed_size)
+{
+	int i;
+	for (i = 0; i < pages_count; i++) {
+		if (!is_write && consumed_size > 0) {
+			set_page_dirty(pages[i]);
+		}
+		put_page(pages[i]);
+	}
+}
+
+/* Populate the call parameters, merging adjacent pages together */
+static void populate_rw_params(
+	struct page **pages, int pages_count,
+	unsigned long address, unsigned long address_end,
+	unsigned long first_page, unsigned long last_page,
+	unsigned iter_last_page_size, int is_write,
+	struct goldfish_pipe_command *command)
+{
+	/*
+	 * Process the first page separately - it's the only page that
+	 * needs special handling for its start address.
+	 */
+	unsigned long xaddr = page_to_phys(pages[0]);
+	unsigned long xaddr_prev = xaddr;
+	int buffer_idx = 0;
+	int i = 1;
+	int size_on_page = first_page == last_page
+			? (int)(address_end - address)
+			: (PAGE_SIZE - (address & ~PAGE_MASK));
+	command->rw_params.ptrs[0] = (u64)(xaddr | (address & ~PAGE_MASK));
+	command->rw_params.sizes[0] = size_on_page;
+	for (; i < pages_count; ++i) {
+		xaddr = page_to_phys(pages[i]);
+		size_on_page = (i == pages_count - 1) ? iter_last_page_size : PAGE_SIZE;
+		if (xaddr == xaddr_prev + PAGE_SIZE) {
+			command->rw_params.sizes[buffer_idx] += size_on_page;
+		} else {
+			++buffer_idx;
+			command->rw_params.ptrs[buffer_idx] = (u64)xaddr;
+			command->rw_params.sizes[buffer_idx] = size_on_page;
+		}
+		xaddr_prev = xaddr;
+	}
+	command->rw_params.buffers_count = buffer_idx + 1;
+}
+
+static int transfer_max_buffers(struct goldfish_pipe* pipe,
+	unsigned long address, unsigned long address_end, int is_write,
+	unsigned long last_page, unsigned int last_page_size,
+	s32* consumed_size, int* status)
+{
+	struct page *pages[MAX_BUFFERS_PER_COMMAND];
+	unsigned long first_page = address & PAGE_MASK;
+	unsigned int iter_last_page_size;
+	int pages_count = pin_user_pages(first_page, last_page,
+			last_page_size, is_write,
+			pages, &iter_last_page_size);
+	if (pages_count < 0)
+		return pages_count;
+
+	/* Serialize access to the pipe command buffers */
+	if (mutex_lock_interruptible(&pipe->lock))
+		return -ERESTARTSYS;
+
+	populate_rw_params(pages, pages_count, address, address_end,
+		first_page, last_page, iter_last_page_size, is_write,
+		pipe->command_buffer);
+
+	/* Transfer the data */
+	*status = goldfish_cmd_locked(pipe,
+						is_write ? PIPE_CMD_WRITE : PIPE_CMD_READ);
+
+	*consumed_size = pipe->command_buffer->rw_params.consumed_size;
+
+	mutex_unlock(&pipe->lock);
+
+	release_user_pages(pages, pages_count, is_write, *consumed_size);
+
+	return 0;
+}
+
+static int wait_for_host_signal(struct goldfish_pipe *pipe, int is_write)
+{
+	u32 wakeBit = is_write ? BIT_WAKE_ON_WRITE : BIT_WAKE_ON_READ;
+	set_bit(wakeBit, &pipe->flags);
+
+	/* Tell the emulator we're going to wait for a wake event */
+	(void)goldfish_cmd(pipe,
+			is_write ? PIPE_CMD_WAKE_ON_WRITE : PIPE_CMD_WAKE_ON_READ);
+
+	while (test_bit(wakeBit, &pipe->flags)) {
+		if (wait_event_interruptible(
+				pipe->wake_queue,
+				!test_bit(wakeBit, &pipe->flags)))
+			return -ERESTARTSYS;
+
+		if (test_bit(BIT_CLOSED_ON_HOST, &pipe->flags))
+			return -EIO;
+	}
+
+	return 0;
+}
+
+static ssize_t goldfish_pipe_read_write(struct file *filp,
+	char __user *buffer, size_t bufflen, int is_write)
+{
+	struct goldfish_pipe *pipe = filp->private_data;
+	int count = 0, ret = -EINVAL;
+	unsigned long address, address_end, last_page;
+	unsigned int last_page_size;
+
+	/* If the emulator already closed the pipe, no need to go further */
+	if (unlikely(test_bit(BIT_CLOSED_ON_HOST, &pipe->flags)))
+		return -EIO;
+	/* Null reads or writes succeeds */
+	if (unlikely(bufflen == 0))
+		return 0;
+	/* Check the buffer range for access */
+	if (unlikely(!access_ok(is_write ? VERIFY_WRITE : VERIFY_READ,
+			buffer, bufflen)))
+		return -EFAULT;
+
+	address = (unsigned long)buffer;
+	address_end = address + bufflen;
+	last_page = (address_end - 1) & PAGE_MASK;
+	last_page_size = ((address_end - 1) & ~PAGE_MASK) + 1;
+
+	while (address < address_end) {
+		s32 consumed_size;
+		int status;
+		ret = transfer_max_buffers(pipe, address, address_end, is_write,
+				last_page, last_page_size, &consumed_size, &status);
+		if (ret < 0)
+			break;
+
+		if (consumed_size > 0) {
+			/* No matter what's the status, we've transfered something */
+			count += consumed_size;
+			address += consumed_size;
+		}
+		if (status > 0)
+			continue;
+		if (status == 0) {
+			/* EOF */
+			ret = 0;
+			break;
+		}
+		if (count > 0) {
+			/*
+			 * An error occured, but we already transfered
+			 * something on one of the previous iterations.
+			 * Just return what we already copied and log this
+			 * err.
+			 */
+			if (status != PIPE_ERROR_AGAIN)
+				pr_info_ratelimited("goldfish_pipe: backend error %d on %s\n",
+									status, is_write ? "write" : "read");
+			break;
+		}
+
+		/*
+		 * If the error is not PIPE_ERROR_AGAIN, or if we are in
+		 * non-blocking mode, just return the error code.
+		 */
+		if (status != PIPE_ERROR_AGAIN || (filp->f_flags & O_NONBLOCK) != 0) {
+			ret = goldfish_pipe_error_convert(status);
+			break;
+		}
+
+		status = wait_for_host_signal(pipe, is_write);
+		if (status < 0)
+			return status;
+	}
+
+	if (count > 0)
+		return count;
+	return ret;
+}
+
+static ssize_t goldfish_pipe_read(struct file *filp, char __user *buffer,
+				size_t bufflen, loff_t *ppos)
+{
+	return goldfish_pipe_read_write(filp, buffer, bufflen, /* is_write */ 0);
+}
+
+static ssize_t goldfish_pipe_write(struct file *filp,
+				const char __user *buffer, size_t bufflen,
+				loff_t *ppos)
+{
+	return goldfish_pipe_read_write(filp,
+			/* cast away the const */(char __user *)buffer, bufflen,
+			/* is_write */ 1);
+}
+
+static unsigned int goldfish_pipe_poll(struct file *filp, poll_table *wait)
+{
+	struct goldfish_pipe *pipe = filp->private_data;
+	unsigned int mask = 0;
+	int status;
+
+	poll_wait(filp, &pipe->wake_queue, wait);
+
+	status = goldfish_cmd(pipe, PIPE_CMD_POLL);
+	if (status < 0) {
+		return -ERESTARTSYS;
+	}
+
+	if (status & PIPE_POLL_IN)
+		mask |= POLLIN | POLLRDNORM;
+	if (status & PIPE_POLL_OUT)
+		mask |= POLLOUT | POLLWRNORM;
+	if (status & PIPE_POLL_HUP)
+		mask |= POLLHUP;
+	if (test_bit(BIT_CLOSED_ON_HOST, &pipe->flags))
+		mask |= POLLERR;
+
+	return mask;
+}
+
+static void signalled_pipes_add_locked(struct goldfish_pipe_dev *dev,
+	u32 id, u32 flags)
+{
+	struct goldfish_pipe *pipe;
+
+	BUG_ON(id >= dev->pipes_capacity);
+
+	pipe = dev->pipes[id];
+	if (!pipe)
+		return;
+	pipe->signalled_flags |= flags;
+
+	if (pipe->prev_signalled || pipe->next_signalled
+		|| dev->first_signalled_pipe == pipe)
+		return;	/* already in the list */
+	pipe->next_signalled = dev->first_signalled_pipe;
+	if (dev->first_signalled_pipe) {
+		dev->first_signalled_pipe->prev_signalled = pipe;
+	}
+	dev->first_signalled_pipe = pipe;
+}
+
+static void signalled_pipes_remove_locked(struct goldfish_pipe_dev *dev,
+	struct goldfish_pipe *pipe) {
+	if (pipe->prev_signalled)
+		pipe->prev_signalled->next_signalled = pipe->next_signalled;
+	if (pipe->next_signalled)
+		pipe->next_signalled->prev_signalled = pipe->prev_signalled;
+	if (pipe == dev->first_signalled_pipe)
+		dev->first_signalled_pipe = pipe->next_signalled;
+	pipe->prev_signalled = NULL;
+	pipe->next_signalled = NULL;
+}
+
+static struct goldfish_pipe *signalled_pipes_pop_front(struct goldfish_pipe_dev *dev,
+		int *wakes)
+{
+	struct goldfish_pipe *pipe;
+	unsigned long flags;
+	spin_lock_irqsave(&dev->lock, flags);
+
+	pipe = dev->first_signalled_pipe;
+	if (pipe) {
+		*wakes = pipe->signalled_flags;
+		pipe->signalled_flags = 0;
+		/*
+		 * This is an optimized version of signalled_pipes_remove_locked() -
+		 * we want to make it as fast as possible to wake the sleeping pipe
+		 * operations faster
+		 */
+		dev->first_signalled_pipe = pipe->next_signalled;
+		if (dev->first_signalled_pipe)
+			dev->first_signalled_pipe->prev_signalled = NULL;
+		pipe->next_signalled = NULL;
+	}
+
+	spin_unlock_irqrestore(&dev->lock, flags);
+	return pipe;
+}
+
+static void goldfish_interrupt_task(unsigned long unused)
+{
+	struct goldfish_pipe_dev *dev = pipe_dev;
+	/* Iterate over the signalled pipes and wake them one by one */
+	struct goldfish_pipe *pipe;
+	int wakes;
+	while ((pipe = signalled_pipes_pop_front(dev, &wakes)) != NULL) {
+		if (wakes & PIPE_WAKE_CLOSED) {
+			pipe->flags = 1 << BIT_CLOSED_ON_HOST;
+		} else {
+			if (wakes & PIPE_WAKE_READ)
+				clear_bit(BIT_WAKE_ON_READ, &pipe->flags);
+			if (wakes & PIPE_WAKE_WRITE)
+				clear_bit(BIT_WAKE_ON_WRITE, &pipe->flags);
+		}
+		/*
+		 * wake_up_interruptible() implies a write barrier, so don't explicitly
+		 * add another one here.
+		 */
+		wake_up_interruptible(&pipe->wake_queue);
+	}
+}
+DECLARE_TASKLET(goldfish_interrupt_tasklet, goldfish_interrupt_task, 0);
+
+/*
+ * The general idea of the interrupt handling:
+ *
+ *  1. device raises an interrupt if there's at least one signalled pipe
+ *  2. IRQ handler reads the signalled pipes and their count from the device
+ *  3. device writes them into a shared buffer and returns the count
+ *      it only resets the IRQ if it has returned all signalled pipes,
+ *      otherwise it leaves it raised, so IRQ handler will be called
+ *      again for the next chunk
+ *  4. IRQ handler adds all returned pipes to the device's signalled pipes list
+ *  5. IRQ handler launches a tasklet to process the signalled pipes from the
+ *      list in a separate context
+ */
+static irqreturn_t goldfish_pipe_interrupt(int irq, void *dev_id)
+{
+	u32 count;
+	u32 i;
+	unsigned long flags;
+	struct goldfish_pipe_dev *dev = dev_id;
+	if (dev != pipe_dev)
+		return IRQ_NONE;
+
+	/* Request the signalled pipes from the device */
+	spin_lock_irqsave(&dev->lock, flags);
+
+	count = readl(dev->base + PIPE_REG_GET_SIGNALLED);
+	if (count == 0) {
+		spin_unlock_irqrestore(&dev->lock, flags);
+		return IRQ_NONE;
+	}
+	if (count > MAX_SIGNALLED_PIPES)
+		count = MAX_SIGNALLED_PIPES;
+
+	for (i = 0; i < count; ++i)
+		signalled_pipes_add_locked(dev,
+			dev->buffers->signalled_pipe_buffers[i].id,
+			dev->buffers->signalled_pipe_buffers[i].flags);
+
+	spin_unlock_irqrestore(&dev->lock, flags);
+
+	tasklet_schedule(&goldfish_interrupt_tasklet);
+	return IRQ_HANDLED;
+}
+
+static int get_free_pipe_id_locked(struct goldfish_pipe_dev *dev)
+{
+	int id;
+	for (id = 0; id < dev->pipes_capacity; ++id)
+		if (!dev->pipes[id])
+			return id;
+
+	{
+		/* Reallocate the array */
+		u32 new_capacity = 2 * dev->pipes_capacity;
+		struct goldfish_pipe **pipes =
+				kcalloc(new_capacity, sizeof(*pipes),
+					GFP_ATOMIC);
+		if (!pipes)
+			return -ENOMEM;
+		memcpy(pipes, dev->pipes, sizeof(*pipes) * dev->pipes_capacity);
+		kfree(dev->pipes);
+		dev->pipes = pipes;
+		id = dev->pipes_capacity;
+		dev->pipes_capacity = new_capacity;
+	}
+	return id;
+}
+
+/**
+ *	goldfish_pipe_open - open a channel to the AVD
+ *	@inode: inode of device
+ *	@file: file struct of opener
+ *
+ *	Create a new pipe link between the emulator and the use application.
+ *	Each new request produces a new pipe.
+ *
+ *	Note: we use the pipe ID as a mux. All goldfish emulations are 32bit
+ *	right now so this is fine. A move to 64bit will need this addressing
+ */
+static int goldfish_pipe_open(struct inode *inode, struct file *file)
+{
+	struct goldfish_pipe_dev *dev = pipe_dev;
+	unsigned long flags;
+	int id;
+	int status;
+
+	/* Allocate new pipe kernel object */
+	struct goldfish_pipe *pipe = kzalloc(sizeof(*pipe), GFP_KERNEL);
+	if (pipe == NULL)
+		return -ENOMEM;
+
+	pipe->dev = dev;
+	mutex_init(&pipe->lock);
+	init_waitqueue_head(&pipe->wake_queue);
+
+	/*
+	 * Command buffer needs to be allocated on its own page to make sure it is
+	 * physically contiguous in host's address space.
+	 */
+	pipe->command_buffer =
+			(struct goldfish_pipe_command*)__get_free_page(GFP_KERNEL);
+	if (!pipe->command_buffer) {
+		status = -ENOMEM;
+		goto err_pipe;
+	}
+
+	spin_lock_irqsave(&dev->lock, flags);
+
+	id = get_free_pipe_id_locked(dev);
+	if (id < 0) {
+		status = id;
+		goto err_id_locked;
+	}
+
+	dev->pipes[id] = pipe;
+	pipe->id = id;
+	pipe->command_buffer->id = id;
+
+	/* Now tell the emulator we're opening a new pipe. */
+	dev->buffers->open_command_params.rw_params_max_count =
+			MAX_BUFFERS_PER_COMMAND;
+	dev->buffers->open_command_params.command_buffer_ptr =
+			(u64)(unsigned long)__pa(pipe->command_buffer);
+	status = goldfish_cmd_locked(pipe, PIPE_CMD_OPEN);
+	spin_unlock_irqrestore(&dev->lock, flags);
+	if (status < 0)
+		goto err_cmd;
+	/* All is done, save the pipe into the file's private data field */
+	file->private_data = pipe;
+	return 0;
+
+err_cmd:
+	spin_lock_irqsave(&dev->lock, flags);
+	dev->pipes[id] = NULL;
+err_id_locked:
+	spin_unlock_irqrestore(&dev->lock, flags);
+	free_page((unsigned long)pipe->command_buffer);
+err_pipe:
+	kfree(pipe);
+	return status;
+}
+
+static int goldfish_pipe_release(struct inode *inode, struct file *filp)
+{
+	unsigned long flags;
+	struct goldfish_pipe *pipe = filp->private_data;
+	struct goldfish_pipe_dev *dev = pipe->dev;
+
+	/* The guest is closing the channel, so tell the emulator right now */
+	(void)goldfish_cmd(pipe, PIPE_CMD_CLOSE);
+
+	spin_lock_irqsave(&dev->lock, flags);
+	dev->pipes[pipe->id] = NULL;
+	signalled_pipes_remove_locked(dev, pipe);
+	spin_unlock_irqrestore(&dev->lock, flags);
+
+	filp->private_data = NULL;
+	free_page((unsigned long)pipe->command_buffer);
+	kfree(pipe);
+	return 0;
+}
+
+static const struct file_operations goldfish_pipe_fops = {
+	.owner = THIS_MODULE,
+	.read = goldfish_pipe_read,
+	.write = goldfish_pipe_write,
+	.poll = goldfish_pipe_poll,
+	.open = goldfish_pipe_open,
+	.release = goldfish_pipe_release,
+};
+
+static struct miscdevice goldfish_pipe_dev = {
+	.minor = MISC_DYNAMIC_MINOR,
+	.name = "goldfish_pipe",
+	.fops = &goldfish_pipe_fops,
+};
+
+static int goldfish_pipe_device_init_v2(struct platform_device *pdev)
+{
+	char *page;
+	struct goldfish_pipe_dev *dev = pipe_dev;
+	int err = devm_request_irq(&pdev->dev, dev->irq, goldfish_pipe_interrupt,
+				IRQF_SHARED, "goldfish_pipe", dev);
+	if (err) {
+		dev_err(&pdev->dev, "unable to allocate IRQ for v2\n");
+		return err;
+	}
+
+	err = misc_register(&goldfish_pipe_dev);
+	if (err) {
+		dev_err(&pdev->dev, "unable to register v2 device\n");
+		return err;
+	}
+
+	dev->first_signalled_pipe = NULL;
+	dev->pipes_capacity = INITIAL_PIPES_CAPACITY;
+	dev->pipes = kcalloc(dev->pipes_capacity, sizeof(*dev->pipes), GFP_KERNEL);
+	if (!dev->pipes)
+		return -ENOMEM;
+
+	/*
+	 * We're going to pass two buffers, open_command_params and
+	 * signalled_pipe_buffers, to the host. This means each of those buffers
+	 * needs to be contained in a single physical page. The easiest choice is
+	 * to just allocate a page and place the buffers in it.
+	 */
+	BUG_ON(sizeof(*dev->buffers) > PAGE_SIZE);
+	page = (char*)__get_free_page(GFP_KERNEL);
+	if (!page) {
+		kfree(dev->pipes);
+		return -ENOMEM;
+	}
+	dev->buffers = (struct goldfish_pipe_dev_buffers*)page;
+
+	/* Send the buffer addresses to the host */
+	{
+		u64 paddr = __pa(&dev->buffers->signalled_pipe_buffers);
+		writel((u32)(unsigned long)(paddr >> 32), dev->base + PIPE_REG_SIGNAL_BUFFER_HIGH);
+		writel((u32)(unsigned long)paddr, dev->base + PIPE_REG_SIGNAL_BUFFER);
+		writel((u32)MAX_SIGNALLED_PIPES, dev->base + PIPE_REG_SIGNAL_BUFFER_COUNT);
+
+		paddr = __pa(&dev->buffers->open_command_params);
+		writel((u32)(unsigned long)(paddr >> 32), dev->base + PIPE_REG_OPEN_BUFFER_HIGH);
+		writel((u32)(unsigned long)paddr, dev->base + PIPE_REG_OPEN_BUFFER);
+	}
+	return 0;
+}
+
+static void goldfish_pipe_device_deinit_v2(struct platform_device *pdev) {
+	struct goldfish_pipe_dev *dev = pipe_dev;
+	misc_deregister(&goldfish_pipe_dev);
+	kfree(dev->pipes);
+	free_page((unsigned long)dev->buffers);
+}
+
+static int goldfish_pipe_probe(struct platform_device *pdev)
+{
+	int err;
+	struct resource *r;
+	struct goldfish_pipe_dev *dev = pipe_dev;
+
+	BUG_ON(sizeof(struct goldfish_pipe_command) > PAGE_SIZE);
+
+	/* not thread safe, but this should not happen */
+	WARN_ON(dev->base != NULL);
+
+	spin_lock_init(&dev->lock);
+
+	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (r == NULL || resource_size(r) < PAGE_SIZE) {
+		dev_err(&pdev->dev, "can't allocate i/o page\n");
+		return -EINVAL;
+	}
+	dev->base = devm_ioremap(&pdev->dev, r->start, PAGE_SIZE);
+	if (dev->base == NULL) {
+		dev_err(&pdev->dev, "ioremap failed\n");
+		return -EINVAL;
+	}
+
+	r = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+	if (r == NULL) {
+		err = -EINVAL;
+		goto error;
+	}
+	dev->irq = r->start;
+
+	/*
+	 * Exchange the versions with the host device
+	 *
+	 * Note: v1 driver used to not report its version, so we write it before
+	 *  reading device version back: this allows the host implementation to
+	 *  detect the old driver (if there was no version write before read).
+	 */
+	writel((u32)PIPE_DRIVER_VERSION, dev->base + PIPE_REG_VERSION);
+	dev->version = readl(dev->base + PIPE_REG_VERSION);
+	if (dev->version < PIPE_CURRENT_DEVICE_VERSION) {
+		/* initialize the old device version */
+		err = goldfish_pipe_device_init_v1(pdev);
+	} else {
+		/* Host device supports the new interface */
+		err = goldfish_pipe_device_init_v2(pdev);
+	}
+	if (!err)
+		return 0;
+
+error:
+	dev->base = NULL;
+	return err;
+}
+
+static int goldfish_pipe_remove(struct platform_device *pdev)
+{
+	struct goldfish_pipe_dev *dev = pipe_dev;
+	if (dev->version < PIPE_CURRENT_DEVICE_VERSION)
+		goldfish_pipe_device_deinit_v1(pdev);
+	else
+		goldfish_pipe_device_deinit_v2(pdev);
+	dev->base = NULL;
+	return 0;
+}
+
+static const struct acpi_device_id goldfish_pipe_acpi_match[] = {
+	{ "GFSH0003", 0 },
+	{ },
+};
+MODULE_DEVICE_TABLE(acpi, goldfish_pipe_acpi_match);
+
+static const struct of_device_id goldfish_pipe_of_match[] = {
+	{ .compatible = "google,android-pipe", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, goldfish_pipe_of_match);
+
+static struct platform_driver goldfish_pipe_driver = {
+	.probe = goldfish_pipe_probe,
+	.remove = goldfish_pipe_remove,
+	.driver = {
+		.name = "goldfish_pipe",
+		.of_match_table = goldfish_pipe_of_match,
+		.acpi_match_table = ACPI_PTR(goldfish_pipe_acpi_match),
+	}
+};
+
+module_platform_driver(goldfish_pipe_driver);
+MODULE_AUTHOR("David Turner <digit@google.com>");
+MODULE_LICENSE("GPL");
diff --git a/drivers/power/goldfish_battery.c b/drivers/power/goldfish_battery.c
index a50bb988c69a..f5c525e4482a 100644
--- a/drivers/power/goldfish_battery.c
+++ b/drivers/power/goldfish_battery.c
@@ -24,6 +24,7 @@
 #include <linux/pci.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
+#include <linux/acpi.h>
 
 struct goldfish_battery_data {
 	void __iomem *reg_base;
@@ -227,11 +228,25 @@ static int goldfish_battery_remove(struct platform_device *pdev)
 	return 0;
 }
 
+static const struct of_device_id goldfish_battery_of_match[] = {
+	{ .compatible = "google,goldfish-battery", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, goldfish_battery_of_match);
+
+static const struct acpi_device_id goldfish_battery_acpi_match[] = {
+	{ "GFSH0001", 0 },
+	{ },
+};
+MODULE_DEVICE_TABLE(acpi, goldfish_battery_acpi_match);
+
 static struct platform_driver goldfish_battery_device = {
 	.probe		= goldfish_battery_probe,
 	.remove		= goldfish_battery_remove,
 	.driver = {
-		.name = "goldfish-battery"
+		.name = "goldfish-battery",
+		.of_match_table = goldfish_battery_of_match,
+		.acpi_match_table = ACPI_PTR(goldfish_battery_acpi_match),
 	}
 };
 module_platform_driver(goldfish_battery_device);
diff --git a/drivers/staging/goldfish/Kconfig b/drivers/staging/goldfish/Kconfig
index 4e094602437c..c579141a7bed 100644
--- a/drivers/staging/goldfish/Kconfig
+++ b/drivers/staging/goldfish/Kconfig
@@ -4,6 +4,12 @@ config GOLDFISH_AUDIO
 	---help---
 	  Emulated audio channel for the Goldfish Android Virtual Device
 
+config GOLDFISH_SYNC
+    tristate "Goldfish AVD Sync Driver"
+    depends on GOLDFISH
+	---help---
+	  Emulated sync fences for the Goldfish Android Virtual Device
+
 config MTD_GOLDFISH_NAND
 	tristate "Goldfish NAND device"
 	depends on GOLDFISH
diff --git a/drivers/staging/goldfish/Makefile b/drivers/staging/goldfish/Makefile
index dec34ad58162..0cf525588210 100644
--- a/drivers/staging/goldfish/Makefile
+++ b/drivers/staging/goldfish/Makefile
@@ -4,3 +4,8 @@
 
 obj-$(CONFIG_GOLDFISH_AUDIO) += goldfish_audio.o
 obj-$(CONFIG_MTD_GOLDFISH_NAND)	+= goldfish_nand.o
+
+# and sync
+
+ccflags-y := -Idrivers/staging/android
+obj-$(CONFIG_GOLDFISH_SYNC) += goldfish_sync.o
diff --git a/drivers/staging/goldfish/goldfish_audio.c b/drivers/staging/goldfish/goldfish_audio.c
index b0927e49d0a8..63b79c09b41b 100644
--- a/drivers/staging/goldfish/goldfish_audio.c
+++ b/drivers/staging/goldfish/goldfish_audio.c
@@ -26,7 +26,9 @@
 #include <linux/sched.h>
 #include <linux/dma-mapping.h>
 #include <linux/uaccess.h>
+#include <linux/slab.h>
 #include <linux/goldfish.h>
+#include <linux/acpi.h>
 
 MODULE_AUTHOR("Google, Inc.");
 MODULE_DESCRIPTION("Android QEMU Audio Driver");
@@ -115,6 +117,7 @@ static ssize_t goldfish_audio_read(struct file *fp, char __user *buf,
 				   size_t count, loff_t *pos)
 {
 	struct goldfish_audio *data = fp->private_data;
+	unsigned long irq_flags;
 	int length;
 	int result = 0;
 
@@ -128,6 +131,10 @@ static ssize_t goldfish_audio_read(struct file *fp, char __user *buf,
 		wait_event_interruptible(data->wait, data->buffer_status &
 					 AUDIO_INT_READ_BUFFER_FULL);
 
+		spin_lock_irqsave(&data->lock, irq_flags);
+		data->buffer_status &= ~AUDIO_INT_READ_BUFFER_FULL;
+		spin_unlock_irqrestore(&data->lock, irq_flags);
+
 		length = AUDIO_READ(data, AUDIO_READ_BUFFER_AVAILABLE);
 
 		/* copy data to user space */
@@ -344,11 +351,25 @@ static int goldfish_audio_remove(struct platform_device *pdev)
 	return 0;
 }
 
+static const struct of_device_id goldfish_audio_of_match[] = {
+	{ .compatible = "google,goldfish-audio", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, goldfish_audio_of_match);
+
+static const struct acpi_device_id goldfish_audio_acpi_match[] = {
+	{ "GFSH0005", 0 },
+	{ },
+};
+MODULE_DEVICE_TABLE(acpi, goldfish_audio_acpi_match);
+
 static struct platform_driver goldfish_audio_driver = {
 	.probe		= goldfish_audio_probe,
 	.remove		= goldfish_audio_remove,
 	.driver = {
-		.name = "goldfish_audio"
+		.name = "goldfish_audio",
+		.of_match_table = goldfish_audio_of_match,
+		.acpi_match_table = ACPI_PTR(goldfish_audio_acpi_match),
 	}
 };
 
diff --git a/drivers/staging/goldfish/goldfish_sync.c b/drivers/staging/goldfish/goldfish_sync.c
new file mode 100644
index 000000000000..ba8def29901e
--- /dev/null
+++ b/drivers/staging/goldfish/goldfish_sync.c
@@ -0,0 +1,987 @@
+/*
+ * Copyright (C) 2016 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/fdtable.h>
+#include <linux/file.h>
+#include <linux/init.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+
+#include <linux/interrupt.h>
+#include <linux/kref.h>
+#include <linux/spinlock.h>
+#include <linux/types.h>
+
+#include <linux/io.h>
+#include <linux/mm.h>
+#include <linux/acpi.h>
+
+#include <linux/string.h>
+#include <linux/syscalls.h>
+
+#include "sw_sync.h"
+#include "sync.h"
+
+#define ERR(...) printk(KERN_ERR __VA_ARGS__);
+
+#define INFO(...) printk(KERN_INFO __VA_ARGS__);
+
+#define DPRINT(...) pr_debug(__VA_ARGS__);
+
+#define DTRACE() DPRINT("%s: enter", __func__)
+
+/* The Goldfish sync driver is designed to provide a interface
+ * between the underlying host's sync device and the kernel's
+ * sw_sync.
+ * The purpose of the device/driver is to enable lightweight
+ * creation and signaling of timelines and fences
+ * in order to synchronize the guest with host-side graphics events.
+ *
+ * Each time the interrupt trips, the driver
+ * may perform a sw_sync operation.
+ */
+
+/* The operations are: */
+
+/* Ready signal - used to mark when irq should lower */
+#define CMD_SYNC_READY            0
+
+/* Create a new timeline. writes timeline handle */
+#define CMD_CREATE_SYNC_TIMELINE  1
+
+/* Create a fence object. reads timeline handle and time argument.
+ * Writes fence fd to the SYNC_REG_HANDLE register. */
+#define CMD_CREATE_SYNC_FENCE     2
+
+/* Increments timeline. reads timeline handle and time argument */
+#define CMD_SYNC_TIMELINE_INC     3
+
+/* Destroys a timeline. reads timeline handle */
+#define CMD_DESTROY_SYNC_TIMELINE 4
+
+/* Starts a wait on the host with
+ * the given glsync object and sync thread handle. */
+#define CMD_TRIGGER_HOST_WAIT     5
+
+/* The register layout is: */
+
+#define SYNC_REG_BATCH_COMMAND                0x00 /* host->guest batch commands */
+#define SYNC_REG_BATCH_GUESTCOMMAND           0x04 /* guest->host batch commands */
+#define SYNC_REG_BATCH_COMMAND_ADDR           0x08 /* communicate physical address of host->guest batch commands */
+#define SYNC_REG_BATCH_COMMAND_ADDR_HIGH      0x0c /* 64-bit part */
+#define SYNC_REG_BATCH_GUESTCOMMAND_ADDR      0x10 /* communicate physical address of guest->host commands */
+#define SYNC_REG_BATCH_GUESTCOMMAND_ADDR_HIGH 0x14 /* 64-bit part */
+#define SYNC_REG_INIT                         0x18 /* signals that the device has been probed */
+
+/* There is an ioctl associated with goldfish sync driver.
+ * Make it conflict with ioctls that are not likely to be used
+ * in the emulator.
+ *
+ * '@'	00-0F	linux/radeonfb.h	conflict!
+ * '@'	00-0F	drivers/video/aty/aty128fb.c	conflict!
+ */
+#define GOLDFISH_SYNC_IOC_MAGIC	'@'
+
+#define GOLDFISH_SYNC_IOC_QUEUE_WORK	_IOWR(GOLDFISH_SYNC_IOC_MAGIC, 0, struct goldfish_sync_ioctl_info)
+
+/* The above definitions (command codes, register layout, ioctl definitions)
+ * need to be in sync with the following files:
+ *
+ * Host-side (emulator):
+ * external/qemu/android/emulation/goldfish_sync.h
+ * external/qemu-android/hw/misc/goldfish_sync.c
+ *
+ * Guest-side (system image):
+ * device/generic/goldfish-opengl/system/egl/goldfish_sync.h
+ * device/generic/goldfish/ueventd.ranchu.rc
+ * platform/build/target/board/generic/sepolicy/file_contexts
+ */
+struct goldfish_sync_hostcmd {
+	/* sorted for alignment */
+	uint64_t handle;
+	uint64_t hostcmd_handle;
+	uint32_t cmd;
+	uint32_t time_arg;
+};
+
+struct goldfish_sync_guestcmd {
+	uint64_t host_command; /* uint64_t for alignment */
+	uint64_t glsync_handle;
+	uint64_t thread_handle;
+	uint64_t guest_timeline_handle;
+};
+
+#define GOLDFISH_SYNC_MAX_CMDS 64
+
+struct goldfish_sync_state {
+	char __iomem *reg_base;
+	int irq;
+
+	/* Spinlock protects |to_do| / |to_do_end|. */
+	spinlock_t lock;
+	/* |mutex_lock| protects all concurrent access
+	 * to timelines for both kernel and user space. */
+	struct mutex mutex_lock;
+
+	/* Buffer holding commands issued from host. */
+	struct goldfish_sync_hostcmd to_do[GOLDFISH_SYNC_MAX_CMDS];
+	uint32_t to_do_end;
+
+	/* Addresses for the reading or writing
+	 * of individual commands. The host can directly write
+	 * to |batch_hostcmd| (and then this driver immediately
+	 * copies contents to |to_do|). This driver either replies
+	 * through |batch_hostcmd| or simply issues a
+	 * guest->host command through |batch_guestcmd|.
+	 */
+	struct goldfish_sync_hostcmd *batch_hostcmd;
+	struct goldfish_sync_guestcmd *batch_guestcmd;
+
+	/* Used to give this struct itself to a work queue
+	 * function for executing actual sync commands. */
+	struct work_struct work_item;
+};
+
+static struct goldfish_sync_state global_sync_state[1];
+
+struct goldfish_sync_timeline_obj {
+	struct sw_sync_timeline *sw_sync_tl;
+	uint32_t current_time;
+	/* We need to be careful about when we deallocate
+	 * this |goldfish_sync_timeline_obj| struct.
+	 * In order to ensure proper cleanup, we need to
+	 * consider the triggered host-side wait that may
+	 * still be in flight when the guest close()'s a
+	 * goldfish_sync device's sync context fd (and
+	 * destroys the |sw_sync_tl| field above).
+	 * The host-side wait may raise IRQ
+	 * and tell the kernel to increment the timeline _after_
+	 * the |sw_sync_tl| has already been set to null.
+	 *
+	 * From observations on OpenGL apps and CTS tests, this
+	 * happens at some very low probability upon context
+	 * destruction or process close, but it does happen
+	 * and it needs to be handled properly. Otherwise,
+	 * if we clean up the surrounding |goldfish_sync_timeline_obj|
+	 * too early, any |handle| field of any host->guest command
+	 * might not even point to a null |sw_sync_tl| field,
+	 * but to garbage memory or even a reclaimed |sw_sync_tl|.
+	 * If we do not count such "pending waits" and kfree the object
+	 * immediately upon |goldfish_sync_timeline_destroy|,
+	 * we might get mysterous RCU stalls after running a long
+	 * time because the garbage memory that is being read
+	 * happens to be interpretable as a |spinlock_t| struct
+	 * that is currently in the locked state.
+	 *
+	 * To track when to free the |goldfish_sync_timeline_obj|
+	 * itself, we maintain a kref.
+	 * The kref essentially counts the timeline itself plus
+	 * the number of waits in flight. kref_init/kref_put
+	 * are issued on
+	 * |goldfish_sync_timeline_create|/|goldfish_sync_timeline_destroy|
+	 * and kref_get/kref_put are issued on
+	 * |goldfish_sync_fence_create|/|goldfish_sync_timeline_inc|.
+	 *
+	 * The timeline is destroyed after reference count
+	 * reaches zero, which would happen after
+	 * |goldfish_sync_timeline_destroy| and all pending
+	 * |goldfish_sync_timeline_inc|'s are fulfilled.
+	 *
+	 * NOTE (1): We assume that |fence_create| and
+	 * |timeline_inc| calls are 1:1, otherwise the kref scheme
+	 * will not work. This is a valid assumption as long
+	 * as the host-side virtual device implementation
+	 * does not insert any timeline increments
+	 * that we did not trigger from here.
+	 *
+	 * NOTE (2): The use of kref by itself requires no locks,
+	 * but this does not mean everything works without locks.
+	 * Related timeline operations do require a lock of some sort,
+	 * or at least are not proven to work without it.
+	 * In particualr, we assume that all the operations
+	 * done on the |kref| field above are done in contexts where
+	 * |global_sync_state->mutex_lock| is held. Do not
+	 * remove that lock until everything is proven to work
+	 * without it!!! */
+	struct kref kref;
+};
+
+/* We will call |delete_timeline_obj| when the last reference count
+ * of the kref is decremented. This deletes the sw_sync
+ * timeline object along with the wrapper itself. */
+static void delete_timeline_obj(struct kref* kref) {
+	struct goldfish_sync_timeline_obj* obj =
+		container_of(kref, struct goldfish_sync_timeline_obj, kref);
+
+	sync_timeline_destroy(&obj->sw_sync_tl->obj);
+	obj->sw_sync_tl = NULL;
+	kfree(obj);
+}
+
+static uint64_t gensym_ctr;
+static void gensym(char *dst)
+{
+	sprintf(dst, "goldfish_sync:gensym:%llu", gensym_ctr);
+	gensym_ctr++;
+}
+
+/* |goldfish_sync_timeline_create| assumes that |global_sync_state->mutex_lock|
+ * is held. */
+static struct goldfish_sync_timeline_obj*
+goldfish_sync_timeline_create(void)
+{
+
+	char timeline_name[256];
+	struct sw_sync_timeline *res_sync_tl = NULL;
+	struct goldfish_sync_timeline_obj *res;
+
+	DTRACE();
+
+	gensym(timeline_name);
+
+	res_sync_tl = sw_sync_timeline_create(timeline_name);
+	if (!res_sync_tl) {
+		ERR("Failed to create sw_sync timeline.");
+		return NULL;
+	}
+
+	res = kzalloc(sizeof(struct goldfish_sync_timeline_obj), GFP_KERNEL);
+	res->sw_sync_tl = res_sync_tl;
+	res->current_time = 0;
+	kref_init(&res->kref);
+
+	DPRINT("new timeline_obj=0x%p", res);
+	return res;
+}
+
+/* |goldfish_sync_fence_create| assumes that |global_sync_state->mutex_lock|
+ * is held. */
+static int
+goldfish_sync_fence_create(struct goldfish_sync_timeline_obj *obj,
+							uint32_t val)
+{
+
+	int fd;
+	char fence_name[256];
+	struct sync_pt *syncpt = NULL;
+	struct sync_fence *sync_obj = NULL;
+	struct sw_sync_timeline *tl;
+
+	DTRACE();
+
+	if (!obj) return -1;
+
+	tl = obj->sw_sync_tl;
+
+	syncpt = sw_sync_pt_create(tl, val);
+	if (!syncpt) {
+		ERR("could not create sync point! "
+			"sync_timeline=0x%p val=%d",
+			   tl, val);
+		return -1;
+	}
+
+	fd = get_unused_fd_flags(O_CLOEXEC);
+	if (fd < 0) {
+		ERR("could not get unused fd for sync fence. "
+			"errno=%d", fd);
+		goto err_cleanup_pt;
+	}
+
+	gensym(fence_name);
+
+	sync_obj = sync_fence_create(fence_name, syncpt);
+	if (!sync_obj) {
+		ERR("could not create sync fence! "
+			"sync_timeline=0x%p val=%d sync_pt=0x%p",
+			   tl, val, syncpt);
+		goto err_cleanup_fd_pt;
+	}
+
+	DPRINT("installing sync fence into fd %d sync_obj=0x%p", fd, sync_obj);
+	sync_fence_install(sync_obj, fd);
+	kref_get(&obj->kref);
+
+	return fd;
+
+err_cleanup_fd_pt:
+	put_unused_fd(fd);
+err_cleanup_pt:
+	sync_pt_free(syncpt);
+	return -1;
+}
+
+/* |goldfish_sync_timeline_inc| assumes that |global_sync_state->mutex_lock|
+ * is held. */
+static void
+goldfish_sync_timeline_inc(struct goldfish_sync_timeline_obj *obj, uint32_t inc)
+{
+	DTRACE();
+	/* Just give up if someone else nuked the timeline.
+	 * Whoever it was won't care that it doesn't get signaled. */
+	if (!obj) return;
+
+	DPRINT("timeline_obj=0x%p", obj);
+	sw_sync_timeline_inc(obj->sw_sync_tl, inc);
+	DPRINT("incremented timeline. increment max_time");
+	obj->current_time += inc;
+
+	/* Here, we will end up deleting the timeline object if it
+	 * turns out that this call was a pending increment after
+	 * |goldfish_sync_timeline_destroy| was called. */
+	kref_put(&obj->kref, delete_timeline_obj);
+	DPRINT("done");
+}
+
+/* |goldfish_sync_timeline_destroy| assumes
+ * that |global_sync_state->mutex_lock| is held. */
+static void
+goldfish_sync_timeline_destroy(struct goldfish_sync_timeline_obj *obj)
+{
+	DTRACE();
+	/* See description of |goldfish_sync_timeline_obj| for why we
+	 * should not immediately destroy |obj| */
+	kref_put(&obj->kref, delete_timeline_obj);
+}
+
+static inline void
+goldfish_sync_cmd_queue(struct goldfish_sync_state *sync_state,
+						uint32_t cmd,
+						uint64_t handle,
+						uint32_t time_arg,
+						uint64_t hostcmd_handle)
+{
+	struct goldfish_sync_hostcmd *to_add;
+
+	DTRACE();
+
+	BUG_ON(sync_state->to_do_end == GOLDFISH_SYNC_MAX_CMDS);
+
+	to_add = &sync_state->to_do[sync_state->to_do_end];
+
+	to_add->cmd = cmd;
+	to_add->handle = handle;
+	to_add->time_arg = time_arg;
+	to_add->hostcmd_handle = hostcmd_handle;
+
+	sync_state->to_do_end += 1;
+}
+
+static inline void
+goldfish_sync_hostcmd_reply(struct goldfish_sync_state *sync_state,
+							uint32_t cmd,
+							uint64_t handle,
+							uint32_t time_arg,
+							uint64_t hostcmd_handle)
+{
+	unsigned long irq_flags;
+	struct goldfish_sync_hostcmd *batch_hostcmd =
+		sync_state->batch_hostcmd;
+
+	DTRACE();
+
+	spin_lock_irqsave(&sync_state->lock, irq_flags);
+
+	batch_hostcmd->cmd = cmd;
+	batch_hostcmd->handle = handle;
+	batch_hostcmd->time_arg = time_arg;
+	batch_hostcmd->hostcmd_handle = hostcmd_handle;
+	writel(0, sync_state->reg_base + SYNC_REG_BATCH_COMMAND);
+
+	spin_unlock_irqrestore(&sync_state->lock, irq_flags);
+}
+
+static inline void
+goldfish_sync_send_guestcmd(struct goldfish_sync_state *sync_state,
+							uint32_t cmd,
+							uint64_t glsync_handle,
+							uint64_t thread_handle,
+							uint64_t timeline_handle)
+{
+	unsigned long irq_flags;
+	struct goldfish_sync_guestcmd *batch_guestcmd =
+		sync_state->batch_guestcmd;
+
+	DTRACE();
+
+	spin_lock_irqsave(&sync_state->lock, irq_flags);
+
+	batch_guestcmd->host_command = (uint64_t)cmd;
+	batch_guestcmd->glsync_handle = (uint64_t)glsync_handle;
+	batch_guestcmd->thread_handle = (uint64_t)thread_handle;
+	batch_guestcmd->guest_timeline_handle = (uint64_t)timeline_handle;
+	writel(0, sync_state->reg_base + SYNC_REG_BATCH_GUESTCOMMAND);
+
+	spin_unlock_irqrestore(&sync_state->lock, irq_flags);
+}
+
+/* |goldfish_sync_interrupt| handles IRQ raises from the virtual device.
+ * In the context of OpenGL, this interrupt will fire whenever we need
+ * to signal a fence fd in the guest, with the command
+ * |CMD_SYNC_TIMELINE_INC|.
+ * However, because this function will be called in an interrupt context,
+ * it is necessary to do the actual work of signaling off of interrupt context.
+ * The shared work queue is used for this purpose. At the end when
+ * all pending commands are intercepted by the interrupt handler,
+ * we call |schedule_work|, which will later run the actual
+ * desired sync command in |goldfish_sync_work_item_fn|.
+ */
+static irqreturn_t goldfish_sync_interrupt(int irq, void *dev_id)
+{
+
+	struct goldfish_sync_state *sync_state = dev_id;
+
+	uint32_t nextcmd;
+	uint32_t command_r;
+	uint64_t handle_rw;
+	uint32_t time_r;
+	uint64_t hostcmd_handle_rw;
+
+	int count = 0;
+
+	DTRACE();
+
+	sync_state = dev_id;
+
+	spin_lock(&sync_state->lock);
+
+	for (;;) {
+
+		readl(sync_state->reg_base + SYNC_REG_BATCH_COMMAND);
+		nextcmd = sync_state->batch_hostcmd->cmd;
+
+		if (nextcmd == 0)
+			break;
+
+		command_r = nextcmd;
+		handle_rw = sync_state->batch_hostcmd->handle;
+		time_r = sync_state->batch_hostcmd->time_arg;
+		hostcmd_handle_rw = sync_state->batch_hostcmd->hostcmd_handle;
+
+		goldfish_sync_cmd_queue(
+				sync_state,
+				command_r,
+				handle_rw,
+				time_r,
+				hostcmd_handle_rw);
+
+		count++;
+	}
+
+	spin_unlock(&sync_state->lock);
+
+	schedule_work(&sync_state->work_item);
+
+	return (count == 0) ? IRQ_NONE : IRQ_HANDLED;
+}
+
+/* |goldfish_sync_work_item_fn| does the actual work of servicing
+ * host->guest sync commands. This function is triggered whenever
+ * the IRQ for the goldfish sync device is raised. Once it starts
+ * running, it grabs the contents of the buffer containing the
+ * commands it needs to execute (there may be multiple, because
+ * our IRQ is active high and not edge triggered), and then
+ * runs all of them one after the other.
+ */
+static void goldfish_sync_work_item_fn(struct work_struct *input)
+{
+
+	struct goldfish_sync_state *sync_state;
+	int sync_fence_fd;
+
+	struct goldfish_sync_timeline_obj *timeline;
+	uint64_t timeline_ptr;
+
+	uint64_t hostcmd_handle;
+
+	uint32_t cmd;
+	uint64_t handle;
+	uint32_t time_arg;
+
+	struct goldfish_sync_hostcmd *todo;
+	uint32_t todo_end;
+
+	unsigned long irq_flags;
+
+	struct goldfish_sync_hostcmd to_run[GOLDFISH_SYNC_MAX_CMDS];
+	uint32_t i = 0;
+
+	sync_state = container_of(input, struct goldfish_sync_state, work_item);
+
+	mutex_lock(&sync_state->mutex_lock);
+
+	spin_lock_irqsave(&sync_state->lock, irq_flags); {
+
+		todo_end = sync_state->to_do_end;
+
+		DPRINT("num sync todos: %u", sync_state->to_do_end);
+
+		for (i = 0; i < todo_end; i++)
+			to_run[i] = sync_state->to_do[i];
+
+		/* We expect that commands will come in at a slow enough rate
+		 * so that incoming items will not be more than
+		 * GOLDFISH_SYNC_MAX_CMDS.
+		 *
+		 * This is because the way the sync device is used,
+		 * it's only for managing buffer data transfers per frame,
+		 * with a sequential dependency between putting things in
+		 * to_do and taking them out. Once a set of commands is
+		 * queued up in to_do, the user of the device waits for
+		 * them to be processed before queuing additional commands,
+		 * which limits the rate at which commands come in
+		 * to the rate at which we take them out here.
+		 *
+		 * We also don't expect more than MAX_CMDS to be issued
+		 * at once; there is a correspondence between
+		 * which buffers need swapping to the (display / buffer queue)
+		 * to particular commands, and we don't expect there to be
+		 * enough display or buffer queues in operation at once
+		 * to overrun GOLDFISH_SYNC_MAX_CMDS.
+		 */
+		sync_state->to_do_end = 0;
+
+	} spin_unlock_irqrestore(&sync_state->lock, irq_flags);
+
+	for (i = 0; i < todo_end; i++) {
+		DPRINT("todo index: %u", i);
+
+		todo = &to_run[i];
+
+		cmd = todo->cmd;
+
+		handle = (uint64_t)todo->handle;
+		time_arg = todo->time_arg;
+		hostcmd_handle = (uint64_t)todo->hostcmd_handle;
+
+		DTRACE();
+
+		timeline = (struct goldfish_sync_timeline_obj *)(uintptr_t)handle;
+
+		switch (cmd) {
+		case CMD_SYNC_READY:
+			break;
+		case CMD_CREATE_SYNC_TIMELINE:
+			DPRINT("exec CMD_CREATE_SYNC_TIMELINE: "
+					"handle=0x%llx time_arg=%d",
+					handle, time_arg);
+			timeline = goldfish_sync_timeline_create();
+			timeline_ptr = (uintptr_t)timeline;
+			goldfish_sync_hostcmd_reply(sync_state, CMD_CREATE_SYNC_TIMELINE,
+										timeline_ptr,
+										0,
+										hostcmd_handle);
+			DPRINT("sync timeline created: %p", timeline);
+			break;
+		case CMD_CREATE_SYNC_FENCE:
+			DPRINT("exec CMD_CREATE_SYNC_FENCE: "
+					"handle=0x%llx time_arg=%d",
+					handle, time_arg);
+			sync_fence_fd = goldfish_sync_fence_create(timeline, time_arg);
+			goldfish_sync_hostcmd_reply(sync_state, CMD_CREATE_SYNC_FENCE,
+										sync_fence_fd,
+										0,
+										hostcmd_handle);
+			break;
+		case CMD_SYNC_TIMELINE_INC:
+			DPRINT("exec CMD_SYNC_TIMELINE_INC: "
+					"handle=0x%llx time_arg=%d",
+					handle, time_arg);
+			goldfish_sync_timeline_inc(timeline, time_arg);
+			break;
+		case CMD_DESTROY_SYNC_TIMELINE:
+			DPRINT("exec CMD_DESTROY_SYNC_TIMELINE: "
+					"handle=0x%llx time_arg=%d",
+					handle, time_arg);
+			goldfish_sync_timeline_destroy(timeline);
+			break;
+		}
+		DPRINT("Done executing sync command");
+	}
+	mutex_unlock(&sync_state->mutex_lock);
+}
+
+/* Guest-side interface: file operations */
+
+/* Goldfish sync context and ioctl info.
+ *
+ * When a sync context is created by open()-ing the goldfish sync device, we
+ * create a sync context (|goldfish_sync_context|).
+ *
+ * Currently, the only data required to track is the sync timeline itself
+ * along with the current time, which are all packed up in the
+ * |goldfish_sync_timeline_obj| field. We use a |goldfish_sync_context|
+ * as the filp->private_data.
+ *
+ * Next, when a sync context user requests that work be queued and a fence
+ * fd provided, we use the |goldfish_sync_ioctl_info| struct, which holds
+ * information about which host handles to touch for this particular
+ * queue-work operation. We need to know about the host-side sync thread
+ * and the particular host-side GLsync object. We also possibly write out
+ * a file descriptor.
+ */
+struct goldfish_sync_context {
+	struct goldfish_sync_timeline_obj *timeline;
+};
+
+struct goldfish_sync_ioctl_info {
+	uint64_t host_glsync_handle_in;
+	uint64_t host_syncthread_handle_in;
+	int fence_fd_out;
+};
+
+static int goldfish_sync_open(struct inode *inode, struct file *file)
+{
+
+	struct goldfish_sync_context *sync_context;
+
+	DTRACE();
+
+	mutex_lock(&global_sync_state->mutex_lock);
+
+	sync_context = kzalloc(sizeof(struct goldfish_sync_context), GFP_KERNEL);
+
+	if (sync_context == NULL) {
+		ERR("Creation of goldfish sync context failed!");
+		mutex_unlock(&global_sync_state->mutex_lock);
+		return -ENOMEM;
+	}
+
+	sync_context->timeline = NULL;
+
+	file->private_data = sync_context;
+
+	DPRINT("successfully create a sync context @0x%p", sync_context);
+
+	mutex_unlock(&global_sync_state->mutex_lock);
+
+	return 0;
+}
+
+static int goldfish_sync_release(struct inode *inode, struct file *file)
+{
+
+	struct goldfish_sync_context *sync_context;
+
+	DTRACE();
+
+	mutex_lock(&global_sync_state->mutex_lock);
+
+	sync_context = file->private_data;
+
+	if (sync_context->timeline)
+		goldfish_sync_timeline_destroy(sync_context->timeline);
+
+	sync_context->timeline = NULL;
+
+	kfree(sync_context);
+
+	mutex_unlock(&global_sync_state->mutex_lock);
+
+	return 0;
+}
+
+/* |goldfish_sync_ioctl| is the guest-facing interface of goldfish sync
+ * and is used in conjunction with eglCreateSyncKHR to queue up the
+ * actual work of waiting for the EGL sync command to complete,
+ * possibly returning a fence fd to the guest.
+ */
+static long goldfish_sync_ioctl(struct file *file,
+								unsigned int cmd,
+								unsigned long arg)
+{
+	struct goldfish_sync_context *sync_context_data;
+	struct goldfish_sync_timeline_obj *timeline;
+	int fd_out;
+	struct goldfish_sync_ioctl_info ioctl_data;
+
+	DTRACE();
+
+	sync_context_data = file->private_data;
+	fd_out = -1;
+
+	switch (cmd) {
+	case GOLDFISH_SYNC_IOC_QUEUE_WORK:
+
+		DPRINT("exec GOLDFISH_SYNC_IOC_QUEUE_WORK");
+
+		mutex_lock(&global_sync_state->mutex_lock);
+
+		if (copy_from_user(&ioctl_data,
+						(void __user *)arg,
+						sizeof(ioctl_data))) {
+			ERR("Failed to copy memory for ioctl_data from user.");
+			mutex_unlock(&global_sync_state->mutex_lock);
+			return -EFAULT;
+		}
+
+		if (ioctl_data.host_syncthread_handle_in == 0) {
+			DPRINT("Error: zero host syncthread handle!!!");
+			mutex_unlock(&global_sync_state->mutex_lock);
+			return -EFAULT;
+		}
+
+		if (!sync_context_data->timeline) {
+			DPRINT("no timeline yet, create one.");
+			sync_context_data->timeline = goldfish_sync_timeline_create();
+			DPRINT("timeline: 0x%p", &sync_context_data->timeline);
+		}
+
+		timeline = sync_context_data->timeline;
+		fd_out = goldfish_sync_fence_create(timeline,
+											timeline->current_time + 1);
+		DPRINT("Created fence with fd %d and current time %u (timeline: 0x%p)",
+			   fd_out,
+			   sync_context_data->timeline->current_time + 1,
+			   sync_context_data->timeline);
+
+		ioctl_data.fence_fd_out = fd_out;
+
+		if (copy_to_user((void __user *)arg,
+						&ioctl_data,
+						sizeof(ioctl_data))) {
+			DPRINT("Error, could not copy to user!!!");
+
+			sys_close(fd_out);
+			/* We won't be doing an increment, kref_put immediately. */
+			kref_put(&timeline->kref, delete_timeline_obj);
+			mutex_unlock(&global_sync_state->mutex_lock);
+			return -EFAULT;
+		}
+
+		/* We are now about to trigger a host-side wait;
+		 * accumulate on |pending_waits|. */
+		goldfish_sync_send_guestcmd(global_sync_state,
+				CMD_TRIGGER_HOST_WAIT,
+				ioctl_data.host_glsync_handle_in,
+				ioctl_data.host_syncthread_handle_in,
+				(uint64_t)(uintptr_t)(sync_context_data->timeline));
+
+		mutex_unlock(&global_sync_state->mutex_lock);
+		return 0;
+	default:
+		return -ENOTTY;
+	}
+}
+
+static const struct file_operations goldfish_sync_fops = {
+	.owner = THIS_MODULE,
+	.open = goldfish_sync_open,
+	.release = goldfish_sync_release,
+	.unlocked_ioctl = goldfish_sync_ioctl,
+	.compat_ioctl = goldfish_sync_ioctl,
+};
+
+static struct miscdevice goldfish_sync_device = {
+	.name = "goldfish_sync",
+	.fops = &goldfish_sync_fops,
+};
+
+
+static bool setup_verify_batch_cmd_addr(struct goldfish_sync_state *sync_state,
+										void *batch_addr,
+										uint32_t addr_offset,
+										uint32_t addr_offset_high)
+{
+	uint64_t batch_addr_phys;
+	uint32_t batch_addr_phys_test_lo;
+	uint32_t batch_addr_phys_test_hi;
+
+	if (!batch_addr) {
+		ERR("Could not use batch command address!");
+		return false;
+	}
+
+	batch_addr_phys = virt_to_phys(batch_addr);
+	writel((uint32_t)(batch_addr_phys),
+			sync_state->reg_base + addr_offset);
+	writel((uint32_t)(batch_addr_phys >> 32),
+			sync_state->reg_base + addr_offset_high);
+
+	batch_addr_phys_test_lo =
+		readl(sync_state->reg_base + addr_offset);
+	batch_addr_phys_test_hi =
+		readl(sync_state->reg_base + addr_offset_high);
+
+	if (virt_to_phys(batch_addr) !=
+			(((uint64_t)batch_addr_phys_test_hi << 32) |
+			 batch_addr_phys_test_lo)) {
+		ERR("Invalid batch command address!");
+		return false;
+	}
+
+	return true;
+}
+
+int goldfish_sync_probe(struct platform_device *pdev)
+{
+	struct resource *ioresource;
+	struct goldfish_sync_state *sync_state = global_sync_state;
+	int status;
+
+	DTRACE();
+
+	sync_state->to_do_end = 0;
+
+	spin_lock_init(&sync_state->lock);
+	mutex_init(&sync_state->mutex_lock);
+
+	platform_set_drvdata(pdev, sync_state);
+
+	ioresource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (ioresource == NULL) {
+		ERR("platform_get_resource failed");
+		return -ENODEV;
+	}
+
+	sync_state->reg_base = devm_ioremap(&pdev->dev, ioresource->start, PAGE_SIZE);
+	if (sync_state->reg_base == NULL) {
+		ERR("Could not ioremap");
+		return -ENOMEM;
+	}
+
+	sync_state->irq = platform_get_irq(pdev, 0);
+	if (sync_state->irq < 0) {
+		ERR("Could not platform_get_irq");
+		return -ENODEV;
+	}
+
+	status = devm_request_irq(&pdev->dev,
+							sync_state->irq,
+							goldfish_sync_interrupt,
+							IRQF_SHARED,
+							pdev->name,
+							sync_state);
+	if (status) {
+		ERR("request_irq failed");
+		return -ENODEV;
+	}
+
+	INIT_WORK(&sync_state->work_item,
+			  goldfish_sync_work_item_fn);
+
+	misc_register(&goldfish_sync_device);
+
+	/* Obtain addresses for batch send/recv of commands. */
+	{
+		struct goldfish_sync_hostcmd *batch_addr_hostcmd;
+		struct goldfish_sync_guestcmd *batch_addr_guestcmd;
+
+		batch_addr_hostcmd = devm_kzalloc(&pdev->dev, sizeof(struct goldfish_sync_hostcmd),
+				GFP_KERNEL);
+		batch_addr_guestcmd = devm_kzalloc(&pdev->dev, sizeof(struct goldfish_sync_guestcmd),
+				GFP_KERNEL);
+
+		if (!setup_verify_batch_cmd_addr(sync_state,
+					batch_addr_hostcmd,
+					SYNC_REG_BATCH_COMMAND_ADDR,
+					SYNC_REG_BATCH_COMMAND_ADDR_HIGH)) {
+			ERR("goldfish_sync: Could not setup batch command address");
+			return -ENODEV;
+		}
+
+		if (!setup_verify_batch_cmd_addr(sync_state,
+					batch_addr_guestcmd,
+					SYNC_REG_BATCH_GUESTCOMMAND_ADDR,
+					SYNC_REG_BATCH_GUESTCOMMAND_ADDR_HIGH)) {
+			ERR("goldfish_sync: Could not setup batch guest command address");
+			return -ENODEV;
+		}
+
+		sync_state->batch_hostcmd = batch_addr_hostcmd;
+		sync_state->batch_guestcmd = batch_addr_guestcmd;
+	}
+
+	INFO("goldfish_sync: Initialized goldfish sync device");
+
+	writel(0, sync_state->reg_base + SYNC_REG_INIT);
+
+	return 0;
+}
+
+static int goldfish_sync_remove(struct platform_device *pdev)
+{
+	struct goldfish_sync_state *sync_state = global_sync_state;
+
+	DTRACE();
+
+	misc_deregister(&goldfish_sync_device);
+	memset(sync_state, 0, sizeof(struct goldfish_sync_state));
+	return 0;
+}
+
+static const struct of_device_id goldfish_sync_of_match[] = {
+	{ .compatible = "google,goldfish-sync", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, goldfish_sync_of_match);
+
+static const struct acpi_device_id goldfish_sync_acpi_match[] = {
+	{ "GFSH0006", 0 },
+	{ },
+};
+
+MODULE_DEVICE_TABLE(acpi, goldfish_sync_acpi_match);
+
+static struct platform_driver goldfish_sync = {
+	.probe = goldfish_sync_probe,
+	.remove = goldfish_sync_remove,
+	.driver = {
+		.name = "goldfish_sync",
+		.of_match_table = goldfish_sync_of_match,
+		.acpi_match_table = ACPI_PTR(goldfish_sync_acpi_match),
+	}
+};
+
+module_platform_driver(goldfish_sync);
+
+MODULE_AUTHOR("Google, Inc.");
+MODULE_DESCRIPTION("Android QEMU Sync Driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION("1.0");
+
+/* This function is only to run a basic test of sync framework.
+ * It creates a timeline and fence object whose signal point is at 1.
+ * The timeline is incremented, and we use the sync framework's
+ * sync_fence_wait on that fence object. If everything works out,
+ * we should not hang in the wait and return immediately.
+ * There is no way to explicitly run this test yet, but it
+ * can be used by inserting it at the end of goldfish_sync_probe.
+ */
+void test_kernel_sync(void)
+{
+	struct goldfish_sync_timeline_obj *test_timeline;
+	int test_fence_fd;
+
+	DTRACE();
+
+	DPRINT("test sw_sync");
+
+	test_timeline = goldfish_sync_timeline_create();
+	DPRINT("sw_sync_timeline_create -> 0x%p", test_timeline);
+
+	test_fence_fd = goldfish_sync_fence_create(test_timeline, 1);
+	DPRINT("sync_fence_create -> %d", test_fence_fd);
+
+	DPRINT("incrementing test timeline");
+	goldfish_sync_timeline_inc(test_timeline, 1);
+
+	DPRINT("test waiting (should NOT hang)");
+	sync_fence_wait(
+			sync_fence_fdget(test_fence_fd), -1);
+
+	DPRINT("test waiting (afterward)");
+}
diff --git a/drivers/tty/goldfish.c b/drivers/tty/goldfish.c
index 0f82c0b146f6..1e332855b933 100644
--- a/drivers/tty/goldfish.c
+++ b/drivers/tty/goldfish.c
@@ -68,8 +68,7 @@ static void goldfish_tty_do_write(int line, const char *buf, unsigned count)
 
 static irqreturn_t goldfish_tty_interrupt(int irq, void *dev_id)
 {
-	struct platform_device *pdev = dev_id;
-	struct goldfish_tty *qtty = &goldfish_ttys[pdev->id];
+	struct goldfish_tty *qtty = dev_id;
 	void __iomem *base = qtty->base;
 	unsigned long irq_flags;
 	unsigned char *buf;
@@ -233,6 +232,7 @@ static int goldfish_tty_probe(struct platform_device *pdev)
 	struct device *ttydev;
 	void __iomem *base;
 	u32 irq;
+	unsigned int line;
 
 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (r == NULL)
@@ -248,10 +248,16 @@ static int goldfish_tty_probe(struct platform_device *pdev)
 
 	irq = r->start;
 
-	if (pdev->id >= goldfish_tty_line_count)
-		goto err_unmap;
-
 	mutex_lock(&goldfish_tty_lock);
+
+	if (pdev->id == PLATFORM_DEVID_NONE)
+		line = goldfish_tty_current_line_count;
+	else
+		line = pdev->id;
+
+	if (line >= goldfish_tty_line_count)
+		goto err_create_driver_failed;
+
 	if (goldfish_tty_current_line_count == 0) {
 		ret = goldfish_tty_create_driver();
 		if (ret)
@@ -259,7 +265,7 @@ static int goldfish_tty_probe(struct platform_device *pdev)
 	}
 	goldfish_tty_current_line_count++;
 
-	qtty = &goldfish_ttys[pdev->id];
+	qtty = &goldfish_ttys[line];
 	spin_lock_init(&qtty->lock);
 	tty_port_init(&qtty->port);
 	qtty->port.ops = &goldfish_port_ops;
@@ -269,13 +275,13 @@ static int goldfish_tty_probe(struct platform_device *pdev)
 	writel(GOLDFISH_TTY_CMD_INT_DISABLE, base + GOLDFISH_TTY_CMD);
 
 	ret = request_irq(irq, goldfish_tty_interrupt, IRQF_SHARED,
-						"goldfish_tty", pdev);
+						"goldfish_tty", qtty);
 	if (ret)
 		goto err_request_irq_failed;
 
 
 	ttydev = tty_port_register_device(&qtty->port, goldfish_tty_driver,
-							pdev->id, &pdev->dev);
+							line, &pdev->dev);
 	if (IS_ERR(ttydev)) {
 		ret = PTR_ERR(ttydev);
 		goto err_tty_register_device_failed;
@@ -286,8 +292,9 @@ static int goldfish_tty_probe(struct platform_device *pdev)
 	qtty->console.device = goldfish_tty_console_device;
 	qtty->console.setup = goldfish_tty_console_setup;
 	qtty->console.flags = CON_PRINTBUFFER;
-	qtty->console.index = pdev->id;
+	qtty->console.index = line;
 	register_console(&qtty->console);
+	platform_set_drvdata(pdev, qtty);
 
 	mutex_unlock(&goldfish_tty_lock);
 	return 0;
@@ -307,13 +314,12 @@ err_unmap:
 
 static int goldfish_tty_remove(struct platform_device *pdev)
 {
-	struct goldfish_tty *qtty;
+	struct goldfish_tty *qtty = platform_get_drvdata(pdev);
 
 	mutex_lock(&goldfish_tty_lock);
 
-	qtty = &goldfish_ttys[pdev->id];
 	unregister_console(&qtty->console);
-	tty_unregister_device(goldfish_tty_driver, pdev->id);
+	tty_unregister_device(goldfish_tty_driver, qtty->console.index);
 	iounmap(qtty->base);
 	qtty->base = NULL;
 	free_irq(qtty->irq, pdev);
@@ -324,11 +330,19 @@ static int goldfish_tty_remove(struct platform_device *pdev)
 	return 0;
 }
 
+static const struct of_device_id goldfish_tty_of_match[] = {
+	{ .compatible = "google,goldfish-tty", },
+	{},
+};
+
+MODULE_DEVICE_TABLE(of, goldfish_tty_of_match);
+
 static struct platform_driver goldfish_tty_platform_driver = {
 	.probe = goldfish_tty_probe,
 	.remove = goldfish_tty_remove,
 	.driver = {
-		.name = "goldfish_tty"
+		.name = "goldfish_tty",
+		.of_match_table = goldfish_tty_of_match,
 	}
 };
 
diff --git a/drivers/usb/gadget/function/f_accessory.c b/drivers/usb/gadget/function/f_accessory.c
index 2ca16a577542..9d3ec0e37475 100644
--- a/drivers/usb/gadget/function/f_accessory.c
+++ b/drivers/usb/gadget/function/f_accessory.c
@@ -211,6 +211,7 @@ static inline struct acc_dev *func_to_dev(struct usb_function *f)
 static struct usb_request *acc_request_new(struct usb_ep *ep, int buffer_size)
 {
 	struct usb_request *req = usb_ep_alloc_request(ep, GFP_KERNEL);
+
 	if (!req)
 		return NULL;
 
@@ -1021,6 +1022,7 @@ acc_function_unbind(struct usb_configuration *c, struct usb_function *f)
 static void acc_start_work(struct work_struct *data)
 {
 	char *envp[2] = { "ACCESSORY=START", NULL };
+
 	kobject_uevent_env(&acc_device.this_device->kobj, KOBJ_CHANGE, envp);
 }
 
diff --git a/drivers/usb/gadget/function/f_audio_source.c b/drivers/usb/gadget/function/f_audio_source.c
index 2489a5fa2685..db7903d19c43 100644
--- a/drivers/usb/gadget/function/f_audio_source.c
+++ b/drivers/usb/gadget/function/f_audio_source.c
@@ -310,6 +310,7 @@ static struct device_attribute *audio_source_function_attributes[] = {
 static struct usb_request *audio_request_new(struct usb_ep *ep, int buffer_size)
 {
 	struct usb_request *req = usb_ep_alloc_request(ep, GFP_KERNEL);
+
 	if (!req)
 		return NULL;
 
diff --git a/drivers/usb/gadget/function/f_mtp.c b/drivers/usb/gadget/function/f_mtp.c
index b9e3e97c57c4..d8b69af6e335 100644
--- a/drivers/usb/gadget/function/f_mtp.c
+++ b/drivers/usb/gadget/function/f_mtp.c
@@ -361,6 +361,7 @@ static inline struct mtp_dev *func_to_mtp(struct usb_function *f)
 static struct usb_request *mtp_request_new(struct usb_ep *ep, int buffer_size)
 {
 	struct usb_request *req = usb_ep_alloc_request(ep, GFP_KERNEL);
+
 	if (!req)
 		return NULL;
 
@@ -1121,6 +1122,7 @@ static int mtp_ctrlrequest(struct usb_composite_dev *cdev,
 		} else if (ctrl->bRequest == MTP_REQ_GET_DEVICE_STATUS
 				&& w_index == 0 && w_value == 0) {
 			struct mtp_device_status *status = cdev->req->buf;
+
 			status->wLength =
 				__constant_cpu_to_le16(sizeof(*status));
 
@@ -1143,6 +1145,7 @@ static int mtp_ctrlrequest(struct usb_composite_dev *cdev,
 	/* respond with data transfer or status phase? */
 	if (value >= 0) {
 		int rc;
+
 		cdev->req->zero = value < w_length;
 		cdev->req->length = value;
 		rc = usb_ep_queue(cdev->gadget->ep0, cdev->req, GFP_ATOMIC);
@@ -1378,6 +1381,7 @@ static struct mtp_instance *to_mtp_instance(struct config_item *item)
 static void mtp_attr_release(struct config_item *item)
 {
 	struct mtp_instance *fi_mtp = to_mtp_instance(item);
+
 	usb_put_function_instance(&fi_mtp->func_inst);
 }
 
diff --git a/drivers/video/fbdev/goldfishfb.c b/drivers/video/fbdev/goldfishfb.c
index 7f6c9e6cfc6c..1e56b50e4082 100644
--- a/drivers/video/fbdev/goldfishfb.c
+++ b/drivers/video/fbdev/goldfishfb.c
@@ -26,6 +26,7 @@
 #include <linux/interrupt.h>
 #include <linux/ioport.h>
 #include <linux/platform_device.h>
+#include <linux/acpi.h>
 
 enum {
 	FB_GET_WIDTH        = 0x00,
@@ -234,7 +235,7 @@ static int goldfish_fb_probe(struct platform_device *pdev)
 	fb->fb.var.activate	= FB_ACTIVATE_NOW;
 	fb->fb.var.height	= readl(fb->reg_base + FB_GET_PHYS_HEIGHT);
 	fb->fb.var.width	= readl(fb->reg_base + FB_GET_PHYS_WIDTH);
-	fb->fb.var.pixclock	= 10000;
+	fb->fb.var.pixclock	= 0;
 
 	fb->fb.var.red.offset = 11;
 	fb->fb.var.red.length = 5;
@@ -304,12 +305,25 @@ static int goldfish_fb_remove(struct platform_device *pdev)
 	return 0;
 }
 
+static const struct of_device_id goldfish_fb_of_match[] = {
+	{ .compatible = "google,goldfish-fb", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, goldfish_fb_of_match);
+
+static const struct acpi_device_id goldfish_fb_acpi_match[] = {
+	{ "GFSH0004", 0 },
+	{ },
+};
+MODULE_DEVICE_TABLE(acpi, goldfish_fb_acpi_match);
 
 static struct platform_driver goldfish_fb_driver = {
 	.probe		= goldfish_fb_probe,
 	.remove		= goldfish_fb_remove,
 	.driver = {
-		.name = "goldfish_fb"
+		.name = "goldfish_fb",
+		.of_match_table = goldfish_fb_of_match,
+		.acpi_match_table = ACPI_PTR(goldfish_fb_acpi_match),
 	}
 };