diff options
| -rw-r--r-- | drivers/bus/mhi/Kconfig | 13 | ||||
| -rw-r--r-- | drivers/bus/mhi/Makefile | 3 | ||||
| -rw-r--r-- | drivers/bus/mhi/uci.c | 664 |
3 files changed, 680 insertions, 0 deletions
diff --git a/drivers/bus/mhi/Kconfig b/drivers/bus/mhi/Kconfig index da5cd0c9fc62..5194e8ee50bd 100644 --- a/drivers/bus/mhi/Kconfig +++ b/drivers/bus/mhi/Kconfig @@ -29,3 +29,16 @@ config MHI_BUS_PCI_GENERIC This driver provides MHI PCI controller driver for devices such as Qualcomm SDX55 based PCIe modems. +config MHI_UCI + tristate "MHI UCI" + depends on MHI_BUS + help + MHI based Userspace Client Interface (UCI) driver is used for + transferring raw data between host and device using standard file + operations from userspace. Open, read, write, poll and close + operations are supported by this driver. Please check + mhi_uci_match_table for all supported channels that are exposed to + userspace. + + To compile this driver as a module, choose M here: the module will be + called mhi_uci. diff --git a/drivers/bus/mhi/Makefile b/drivers/bus/mhi/Makefile index 0a2d778d6fb4..69f21116e40c 100644 --- a/drivers/bus/mhi/Makefile +++ b/drivers/bus/mhi/Makefile @@ -4,3 +4,6 @@ obj-y += core/ obj-$(CONFIG_MHI_BUS_PCI_GENERIC) += mhi_pci_generic.o mhi_pci_generic-y += pci_generic.o +# MHI client +mhi_uci-y := uci.o +obj-$(CONFIG_MHI_UCI) += mhi_uci.o diff --git a/drivers/bus/mhi/uci.c b/drivers/bus/mhi/uci.c new file mode 100644 index 000000000000..1df2377f203d --- /dev/null +++ b/drivers/bus/mhi/uci.c @@ -0,0 +1,664 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright (c) 2018-2020, The Linux Foundation. All rights reserved.*/ + +#include <linux/kernel.h> +#include <linux/mhi.h> +#include <linux/mod_devicetable.h> +#include <linux/module.h> +#include <linux/poll.h> + +#define MHI_UCI_DRIVER_NAME "mhi_uci" +#define MHI_MAX_UCI_MINORS 128 + +static DEFINE_IDR(uci_idr); +static DEFINE_MUTEX(uci_drv_mutex); +static struct class *uci_dev_class; +static int uci_dev_major; + +/** + * struct uci_chan - MHI channel for a UCI device + * @udev: associated UCI device object + * @ul_wq: wait queue for writer + * @write_lock: mutex write lock for ul channel + * @dl_wq: wait queue for reader + * @read_lock: mutex read lock for dl channel + * @dl_pending_lock: spin lock for dl_pending list + * @dl_pending: list of dl buffers userspace is waiting to read + * @cur_buf: current buffer userspace is reading + * @dl_size: size of the current dl buffer userspace is reading + * @ref_count: uci_chan reference count + */ +struct uci_chan { + struct uci_dev *udev; + wait_queue_head_t ul_wq; + + /* ul channel lock to synchronize multiple writes */ + struct mutex write_lock; + + wait_queue_head_t dl_wq; + + /* dl channel lock to synchronize multiple reads */ + struct mutex read_lock; + + /* + * protects pending list in bh context, channel release, read and + * poll + */ + spinlock_t dl_pending_lock; + + struct list_head dl_pending; + struct uci_buf *cur_buf; + size_t dl_size; + struct kref ref_count; +}; + +/** + * struct uci_buf - UCI buffer + * @data: data buffer + * @len: length of data buffer + * @node: list node of the UCI buffer + */ +struct uci_buf { + void *data; + size_t len; + struct list_head node; +}; + +/** + * struct uci_dev - MHI UCI device + * @minor: UCI device node minor number + * @mhi_dev: associated mhi device object + * @uchan: UCI uplink and downlink channel object + * @mtu: max TRE buffer length + * @enabled: Flag to track the state of the UCI device + * @lock: mutex lock to manage uchan object + * @ref_count: uci_dev reference count + */ +struct uci_dev { + unsigned int minor; + struct mhi_device *mhi_dev; + struct uci_chan *uchan; + size_t mtu; + bool enabled; + + /* synchronize open, release and driver remove */ + struct mutex lock; + struct kref ref_count; +}; + +static void mhi_uci_dev_chan_release(struct kref *ref) +{ + struct uci_buf *buf_itr, *tmp; + struct uci_chan *uchan = + container_of(ref, struct uci_chan, ref_count); + + if (uchan->udev->enabled) + mhi_unprepare_from_transfer(uchan->udev->mhi_dev); + + spin_lock_bh(&uchan->dl_pending_lock); + list_for_each_entry_safe(buf_itr, tmp, &uchan->dl_pending, node) { + list_del(&buf_itr->node); + kfree(buf_itr->data); + } + spin_unlock_bh(&uchan->dl_pending_lock); + + wake_up(&uchan->ul_wq); + wake_up(&uchan->dl_wq); + + mutex_lock(&uchan->read_lock); + if (uchan->cur_buf) + kfree(uchan->cur_buf->data); + + uchan->cur_buf = NULL; + mutex_unlock(&uchan->read_lock); + + mutex_destroy(&uchan->write_lock); + mutex_destroy(&uchan->read_lock); + + uchan->udev->uchan = NULL; + kfree(uchan); +} + +static int mhi_queue_inbound(struct uci_dev *udev) +{ + struct mhi_device *mhi_dev = udev->mhi_dev; + struct device *dev = &mhi_dev->dev; + int nr_desc, i, ret = -EIO; + size_t dl_buf_size; + void *buf; + struct uci_buf *ubuf; + + /* + * skip queuing without error if dl channel is not supported. This + * allows open to succeed for udev, supporting ul only channel. + */ + if (!udev->mhi_dev->dl_chan) + return 0; + + nr_desc = mhi_get_free_desc_count(mhi_dev, DMA_FROM_DEVICE); + + for (i = 0; i < nr_desc; i++) { + buf = kmalloc(udev->mtu, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + dl_buf_size = udev->mtu - sizeof(*ubuf); + + /* save uci_buf info at the end of buf */ + ubuf = buf + dl_buf_size; + ubuf->data = buf; + + dev_dbg(dev, "Allocated buf %d of %d size %zu\n", i, nr_desc, + dl_buf_size); + + ret = mhi_queue_buf(mhi_dev, DMA_FROM_DEVICE, buf, dl_buf_size, + MHI_EOT); + if (ret) { + kfree(buf); + dev_err(dev, "Failed to queue buffer %d\n", i); + return ret; + } + } + + return ret; +} + +static int mhi_uci_dev_start_chan(struct uci_dev *udev) +{ + int ret = 0; + struct uci_chan *uchan; + + mutex_lock(&udev->lock); + if (!udev->uchan || !kref_get_unless_zero(&udev->uchan->ref_count)) { + uchan = kzalloc(sizeof(*uchan), GFP_KERNEL); + if (!uchan) { + ret = -ENOMEM; + goto error_chan_start; + } + + udev->uchan = uchan; + uchan->udev = udev; + init_waitqueue_head(&uchan->ul_wq); + init_waitqueue_head(&uchan->dl_wq); + mutex_init(&uchan->write_lock); + mutex_init(&uchan->read_lock); + spin_lock_init(&uchan->dl_pending_lock); + INIT_LIST_HEAD(&uchan->dl_pending); + + ret = mhi_prepare_for_transfer(udev->mhi_dev); + if (ret) { + dev_err(&udev->mhi_dev->dev, "Error starting transfer channels\n"); + goto error_chan_cleanup; + } + + ret = mhi_queue_inbound(udev); + if (ret) + goto error_chan_cleanup; + + kref_init(&uchan->ref_count); + } + + mutex_unlock(&udev->lock); + + return 0; + +error_chan_cleanup: + mhi_uci_dev_chan_release(&uchan->ref_count); +error_chan_start: + mutex_unlock(&udev->lock); + return ret; +} + +static void mhi_uci_dev_release(struct kref *ref) +{ + struct uci_dev *udev = + container_of(ref, struct uci_dev, ref_count); + + mutex_destroy(&udev->lock); + + kfree(udev); +} + +static int mhi_uci_open(struct inode *inode, struct file *filp) +{ + unsigned int minor = iminor(inode); + struct uci_dev *udev = NULL; + int ret; + + mutex_lock(&uci_drv_mutex); + udev = idr_find(&uci_idr, minor); + if (!udev) { + pr_debug("uci dev: minor %d not found\n", minor); + mutex_unlock(&uci_drv_mutex); + return -ENODEV; + } + + kref_get(&udev->ref_count); + mutex_unlock(&uci_drv_mutex); + + ret = mhi_uci_dev_start_chan(udev); + if (ret) { + kref_put(&udev->ref_count, mhi_uci_dev_release); + return ret; + } + + filp->private_data = udev; + + return 0; +} + +static int mhi_uci_release(struct inode *inode, struct file *file) +{ + struct uci_dev *udev = file->private_data; + + mutex_lock(&udev->lock); + kref_put(&udev->uchan->ref_count, mhi_uci_dev_chan_release); + mutex_unlock(&udev->lock); + + kref_put(&udev->ref_count, mhi_uci_dev_release); + + return 0; +} + +static __poll_t mhi_uci_poll(struct file *file, poll_table *wait) +{ + struct uci_dev *udev = file->private_data; + struct mhi_device *mhi_dev = udev->mhi_dev; + struct device *dev = &mhi_dev->dev; + struct uci_chan *uchan = udev->uchan; + __poll_t mask = 0; + + poll_wait(file, &udev->uchan->ul_wq, wait); + poll_wait(file, &udev->uchan->dl_wq, wait); + + if (!udev->enabled) { + mask = EPOLLERR; + goto done; + } + + spin_lock_bh(&uchan->dl_pending_lock); + if (!list_empty(&uchan->dl_pending) || uchan->cur_buf) + mask |= EPOLLIN | EPOLLRDNORM; + spin_unlock_bh(&uchan->dl_pending_lock); + + if (mhi_get_free_desc_count(mhi_dev, DMA_TO_DEVICE) > 0) + mask |= EPOLLOUT | EPOLLWRNORM; + + dev_dbg(dev, "Client attempted to poll, returning mask 0x%x\n", mask); + +done: + return mask; +} + +static ssize_t mhi_uci_write(struct file *file, + const char __user *buf, + size_t count, + loff_t *offp) +{ + struct uci_dev *udev = file->private_data; + struct mhi_device *mhi_dev = udev->mhi_dev; + struct device *dev = &mhi_dev->dev; + struct uci_chan *uchan = udev->uchan; + size_t bytes_xfered = 0; + int ret, nr_desc = 0; + + /* if ul channel is not supported return error */ + if (!mhi_dev->ul_chan) + return -EOPNOTSUPP; + + if (!buf || !count) + return -EINVAL; + + dev_dbg(dev, "%s: to xfer: %zu bytes\n", __func__, count); + + if (mutex_lock_interruptible(&uchan->write_lock)) + return -EINTR; + + while (count) { + size_t xfer_size; + void *kbuf; + enum mhi_flags flags; + + /* wait for free descriptors */ + ret = wait_event_interruptible(uchan->ul_wq, + (!udev->enabled) || + (nr_desc = mhi_get_free_desc_count(mhi_dev, + DMA_TO_DEVICE)) > 0); + + if (ret == -ERESTARTSYS) { + dev_dbg(dev, "Interrupted by a signal in %s, exiting\n", + __func__); + goto err_mtx_unlock; + } + + if (!udev->enabled) { + ret = -ENODEV; + goto err_mtx_unlock; + } + + xfer_size = min_t(size_t, count, udev->mtu); + kbuf = kmalloc(xfer_size, GFP_KERNEL); + if (!kbuf) { + ret = -ENOMEM; + goto err_mtx_unlock; + } + + ret = copy_from_user(kbuf, buf, xfer_size); + if (ret) { + kfree(kbuf); + ret = -EFAULT; + goto err_mtx_unlock; + } + + /* if ring is full after this force EOT */ + if (nr_desc > 1 && (count - xfer_size)) + flags = MHI_CHAIN; + else + flags = MHI_EOT; + + ret = mhi_queue_buf(mhi_dev, DMA_TO_DEVICE, kbuf, xfer_size, + flags); + if (ret) { + kfree(kbuf); + goto err_mtx_unlock; + } + + bytes_xfered += xfer_size; + count -= xfer_size; + buf += xfer_size; + } + + mutex_unlock(&uchan->write_lock); + dev_dbg(dev, "%s: bytes xferred: %zu\n", __func__, bytes_xfered); + + return bytes_xfered; + +err_mtx_unlock: + mutex_unlock(&uchan->write_lock); + + return ret; +} + +static ssize_t mhi_uci_read(struct file *file, + char __user *buf, + size_t count, + loff_t *ppos) +{ + struct uci_dev *udev = file->private_data; + struct mhi_device *mhi_dev = udev->mhi_dev; + struct uci_chan *uchan = udev->uchan; + struct device *dev = &mhi_dev->dev; + struct uci_buf *ubuf; + size_t rx_buf_size; + char *ptr; + size_t to_copy; + int ret = 0; + + /* if dl channel is not supported return error */ + if (!mhi_dev->dl_chan) + return -EOPNOTSUPP; + + if (!buf) + return -EINVAL; + + if (mutex_lock_interruptible(&uchan->read_lock)) + return -EINTR; + + spin_lock_bh(&uchan->dl_pending_lock); + /* No data available to read, wait */ + if (!uchan->cur_buf && list_empty(&uchan->dl_pending)) { + dev_dbg(dev, "No data available to read, waiting\n"); + + spin_unlock_bh(&uchan->dl_pending_lock); + ret = wait_event_interruptible(uchan->dl_wq, + (!udev->enabled || + !list_empty(&uchan->dl_pending))); + + if (ret == -ERESTARTSYS) { + dev_dbg(dev, "Interrupted by a signal in %s, exiting\n", + __func__); + goto err_mtx_unlock; + } + + if (!udev->enabled) { + ret = -ENODEV; + goto err_mtx_unlock; + } + spin_lock_bh(&uchan->dl_pending_lock); + } + + /* new read, get the next descriptor from the list */ + if (!uchan->cur_buf) { + ubuf = list_first_entry_or_null(&uchan->dl_pending, + struct uci_buf, node); + if (!ubuf) { + ret = -EIO; + goto err_spin_unlock; + } + + list_del(&ubuf->node); + uchan->cur_buf = ubuf; + uchan->dl_size = ubuf->len; + dev_dbg(dev, "Got pkt of size: %zu\n", uchan->dl_size); + } + spin_unlock_bh(&uchan->dl_pending_lock); + + ubuf = uchan->cur_buf; + + /* Copy the buffer to user space */ + to_copy = min_t(size_t, count, uchan->dl_size); + ptr = ubuf->data + (ubuf->len - uchan->dl_size); + + ret = copy_to_user(buf, ptr, to_copy); + if (ret) { + ret = -EFAULT; + goto err_mtx_unlock; + } + + dev_dbg(dev, "Copied %zu of %zu bytes\n", to_copy, uchan->dl_size); + uchan->dl_size -= to_copy; + + /* we finished with this buffer, queue it back to hardware */ + if (!uchan->dl_size) { + uchan->cur_buf = NULL; + + rx_buf_size = udev->mtu - sizeof(*ubuf); + ret = mhi_queue_buf(mhi_dev, DMA_FROM_DEVICE, ubuf->data, + rx_buf_size, MHI_EOT); + if (ret) { + dev_err(dev, "Failed to recycle element: %d\n", ret); + kfree(ubuf->data); + goto err_mtx_unlock; + } + } + mutex_unlock(&uchan->read_lock); + + dev_dbg(dev, "%s: Returning %zu bytes\n", __func__, to_copy); + + return to_copy; + +err_spin_unlock: + spin_unlock_bh(&uchan->dl_pending_lock); +err_mtx_unlock: + mutex_unlock(&uchan->read_lock); + return ret; +} + +static const struct file_operations mhidev_fops = { + .owner = THIS_MODULE, + .open = mhi_uci_open, + .release = mhi_uci_release, + .read = mhi_uci_read, + .write = mhi_uci_write, + .poll = mhi_uci_poll, +}; + +static void mhi_ul_xfer_cb(struct mhi_device *mhi_dev, + struct mhi_result *mhi_result) +{ + struct uci_dev *udev = dev_get_drvdata(&mhi_dev->dev); + struct uci_chan *uchan = udev->uchan; + struct device *dev = &mhi_dev->dev; + + dev_dbg(dev, "%s: status: %d xfer_len: %zu\n", __func__, + mhi_result->transaction_status, mhi_result->bytes_xferd); + + kfree(mhi_result->buf_addr); + + if (!mhi_result->transaction_status) + wake_up(&uchan->ul_wq); +} + +static void mhi_dl_xfer_cb(struct mhi_device *mhi_dev, + struct mhi_result *mhi_result) +{ + struct uci_dev *udev = dev_get_drvdata(&mhi_dev->dev); + struct uci_chan *uchan = udev->uchan; + struct device *dev = &mhi_dev->dev; + struct uci_buf *ubuf; + size_t dl_buf_size = udev->mtu - sizeof(*ubuf); + + dev_dbg(dev, "%s: status: %d receive_len: %zu\n", __func__, + mhi_result->transaction_status, mhi_result->bytes_xferd); + + if (mhi_result->transaction_status && + mhi_result->transaction_status != -EOVERFLOW) { + kfree(mhi_result->buf_addr); + return; + } + + ubuf = mhi_result->buf_addr + dl_buf_size; + ubuf->data = mhi_result->buf_addr; + ubuf->len = mhi_result->bytes_xferd; + spin_lock_bh(&uchan->dl_pending_lock); + list_add_tail(&ubuf->node, &uchan->dl_pending); + spin_unlock_bh(&uchan->dl_pending_lock); + + wake_up(&uchan->dl_wq); +} + +static int mhi_uci_probe(struct mhi_device *mhi_dev, + const struct mhi_device_id *id) +{ + struct uci_dev *udev; + struct device *dev; + int index; + + udev = kzalloc(sizeof(*udev), GFP_KERNEL); + if (!udev) + return -ENOMEM; + + kref_init(&udev->ref_count); + mutex_init(&udev->lock); + udev->mhi_dev = mhi_dev; + + mutex_lock(&uci_drv_mutex); + index = idr_alloc(&uci_idr, udev, 0, MHI_MAX_UCI_MINORS, GFP_KERNEL); + mutex_unlock(&uci_drv_mutex); + if (index < 0) { + kfree(udev); + return index; + } + + udev->minor = index; + + udev->mtu = min_t(size_t, id->driver_data, MHI_MAX_MTU); + dev_set_drvdata(&mhi_dev->dev, udev); + udev->enabled = true; + + /* create device file node /dev/<mhi_dev_name> */ + dev = device_create(uci_dev_class, &mhi_dev->dev, + MKDEV(uci_dev_major, index), udev, "%s", + dev_name(&mhi_dev->dev)); + if (IS_ERR(dev)) { + mutex_lock(&uci_drv_mutex); + idr_remove(&uci_idr, udev->minor); + mutex_unlock(&uci_drv_mutex); + dev_set_drvdata(&mhi_dev->dev, NULL); + kfree(udev); + return PTR_ERR(dev); + } + + dev_dbg(&mhi_dev->dev, "probed uci dev: %s\n", id->chan); + + return 0; +}; + +static void mhi_uci_remove(struct mhi_device *mhi_dev) +{ + struct uci_dev *udev = dev_get_drvdata(&mhi_dev->dev); + + /* disable the node */ + mutex_lock(&udev->lock); + udev->enabled = false; + + /* delete the node to prevent new opens */ + device_destroy(uci_dev_class, MKDEV(uci_dev_major, udev->minor)); + + /* return error for any blocked read or write */ + if (udev->uchan) { + wake_up(&udev->uchan->ul_wq); + wake_up(&udev->uchan->dl_wq); + } + mutex_unlock(&udev->lock); + + mutex_lock(&uci_drv_mutex); + idr_remove(&uci_idr, udev->minor); + kref_put(&udev->ref_count, mhi_uci_dev_release); + mutex_unlock(&uci_drv_mutex); +} + +/* .driver_data stores max mtu */ +static const struct mhi_device_id mhi_uci_match_table[] = { + { .chan = "QMI", .driver_data = 0x1000}, + {}, +}; +MODULE_DEVICE_TABLE(mhi, mhi_uci_match_table); + +static struct mhi_driver mhi_uci_driver = { + .id_table = mhi_uci_match_table, + .remove = mhi_uci_remove, + .probe = mhi_uci_probe, + .ul_xfer_cb = mhi_ul_xfer_cb, + .dl_xfer_cb = mhi_dl_xfer_cb, + .driver = { + .name = MHI_UCI_DRIVER_NAME, + }, +}; + +static int __init mhi_uci_init(void) +{ + int ret; + + ret = register_chrdev(0, MHI_UCI_DRIVER_NAME, &mhidev_fops); + if (ret < 0) + return ret; + + uci_dev_major = ret; + uci_dev_class = class_create(THIS_MODULE, MHI_UCI_DRIVER_NAME); + if (IS_ERR(uci_dev_class)) { + unregister_chrdev(uci_dev_major, MHI_UCI_DRIVER_NAME); + return PTR_ERR(uci_dev_class); + } + + ret = mhi_driver_register(&mhi_uci_driver); + if (ret) { + class_destroy(uci_dev_class); + unregister_chrdev(uci_dev_major, MHI_UCI_DRIVER_NAME); + } + + return ret; +} + +static void __exit mhi_uci_exit(void) +{ + mhi_driver_unregister(&mhi_uci_driver); + class_destroy(uci_dev_class); + unregister_chrdev(uci_dev_major, MHI_UCI_DRIVER_NAME); + idr_destroy(&uci_idr); +} + +module_init(mhi_uci_init); +module_exit(mhi_uci_exit); +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("MHI UCI Driver"); |