From da5be73548806046aee1cbde68da6c5bba9865c2 Mon Sep 17 00:00:00 2001
From: Thirupathi Chippakurthy <thirupathi.chippakurthy@stericsson.com>
Date: Tue, 13 Sep 2011 17:04:27 +0530
Subject: usb:musb:Enable DMA mode1 RX for without short pkt

This patch enables the DMA mode1 RX support
This feature is enabled based on the short_not_ok flag passed from
gadget drivers.

This will result in a thruput performance gain of around
40% for USB mass-storage/mtp use cases.

ST-Ericsson ID: 352334
ST-Ericsson Linux next: NA
ST-Ericsson FOSS-OUT ID: Trivial

Signed-off-by: <thirupathi.chippakurthy@stericsson.com>
Signed-off-by: Anand Gadiyar <gadiyar <at> ti.com>
Signed-off-by: Moiz Sonasath <m-sonasath <at> ti.com>
Signed-off-by: Vikram Pandita <vikram.pandita <at> ti.com>
Tested-by: Vikram Pandita <vikram.pandita <at> ti.com>
Change-Id: I17f58a018c1b5c0a4d89172fd2978a4e5da337f0
Reviewed-on: http://gerrit.lud.stericsson.com/gerrit/30833
Reviewed-by: Praveena NADAHALLY <praveen.nadahally@stericsson.com>
Reviewed-by: Srinidhi KASAGAR <srinidhi.kasagar@stericsson.com>
---
 drivers/usb/musb/musb_gadget.c | 98 +++++++++++++++++++++++++-----------------
 1 file changed, 58 insertions(+), 40 deletions(-)

(limited to 'drivers/usb')

diff --git a/drivers/usb/musb/musb_gadget.c b/drivers/usb/musb/musb_gadget.c
index e81820370d6..7ae88092e46 100644
--- a/drivers/usb/musb/musb_gadget.c
+++ b/drivers/usb/musb/musb_gadget.c
@@ -634,6 +634,7 @@ static void rxstate(struct musb *musb, struct musb_request *req)
 	u16			len;
 	u16			csr = musb_readw(epio, MUSB_RXCSR);
 	struct musb_hw_ep	*hw_ep = &musb->endpoints[epnum];
+	u8			use_mode_1;
 
 	if (hw_ep->is_shared_fifo)
 		musb_ep = &hw_ep->ep_in;
@@ -683,6 +684,17 @@ static void rxstate(struct musb *musb, struct musb_request *req)
 
 	if (csr & MUSB_RXCSR_RXPKTRDY) {
 		len = musb_readw(epio, MUSB_RXCOUNT);
+
+		/*
+		* Enable Mode 1 on RX transfers only when short_not_ok flag
+		* is set. Currently short_not_ok flag is set only from
+		* file_storage and f_mass_storage drivers
+		*/
+
+		if (request->short_not_ok && len == musb_ep->packet_sz)
+			use_mode_1 = 1;
+		else
+			use_mode_1 = 0;
 		if (request->actual < request->length) {
 #ifdef CONFIG_USB_INVENTRA_DMA
 			if (is_buffer_mapped(req)) {
@@ -714,50 +726,56 @@ static void rxstate(struct musb *musb, struct musb_request *req)
 	 * then becomes usable as a runtime "use mode 1" hint...
 	 */
 
-				csr |= MUSB_RXCSR_DMAENAB;
-#ifdef USE_MODE1
-				csr |= MUSB_RXCSR_AUTOCLEAR;
-				/* csr |= MUSB_RXCSR_DMAMODE; */
+	/* Experimental: Mode1 works with mass storage use cases */
+	if (use_mode_1) {
+		csr |= MUSB_RXCSR_AUTOCLEAR;
 
-				/* this special sequence (enabling and then
-				 * disabling MUSB_RXCSR_DMAMODE) is required
-				 * to get DMAReq to activate
-				 */
-				musb_writew(epio, MUSB_RXCSR,
-					csr | MUSB_RXCSR_DMAMODE);
-#else
-				if (!musb_ep->hb_mult &&
-					musb_ep->hw_ep->rx_double_buffered)
-					csr |= MUSB_RXCSR_AUTOCLEAR;
-#endif
-				musb_writew(epio, MUSB_RXCSR, csr);
+		musb_writew(epio, MUSB_RXCSR, csr);
+		csr |= MUSB_RXCSR_DMAENAB;
+		musb_writew(epio, MUSB_RXCSR, csr);
 
-				if (request->actual < request->length) {
-					int transfer_size = 0;
-#ifdef USE_MODE1
-					transfer_size = min(request->length - request->actual,
-							channel->max_len);
-#else
-					transfer_size = min(request->length - request->actual,
-							(unsigned)len);
-#endif
-					if (transfer_size <= musb_ep->packet_sz)
-						musb_ep->dma->desired_mode = 0;
-					else
-						musb_ep->dma->desired_mode = 1;
+		/*
+		* this special sequence (enabling and then
+		* disabling MUSB_RXCSR_DMAMODE) is required
+		* to get DMAReq to activate
+		*/
 
-					use_dma = c->channel_program(
-							channel,
-							musb_ep->packet_sz,
-							channel->desired_mode,
-							request->dma
-							+ request->actual,
-							transfer_size);
-				}
+		musb_writew(epio, MUSB_RXCSR,
+			csr | MUSB_RXCSR_DMAMODE);
+		musb_writew(epio, MUSB_RXCSR, csr);
+	} else {
+		if (!musb_ep->hb_mult &&
+			musb_ep->hw_ep->rx_double_buffered)
+			csr |= MUSB_RXCSR_AUTOCLEAR;
+			csr |= MUSB_RXCSR_DMAENAB;
+			musb_writew(epio, MUSB_RXCSR, csr);
+	}
 
-				if (use_dma)
-					return;
-			}
+	if (request->actual < request->length) {
+			int transfer_size = 0;
+
+	if (use_mode_1) {
+		transfer_size = min(request->length - request->actual,
+					channel->max_len);
+		musb_ep->dma->desired_mode = 1;
+	} else {
+		transfer_size = min(request->length - request->actual,
+				(unsigned)len);
+		musb_ep->dma->desired_mode = 0;
+	}
+
+		use_dma = c->channel_program(
+				channel,
+				musb_ep->packet_sz,
+				channel->desired_mode,
+				request->dma
+				+ request->actual,
+				transfer_size);
+	}
+
+		if (use_dma)
+			return;
+		}
 #elif defined(CONFIG_USB_UX500_DMA)
 			if ((is_buffer_mapped(req)) &&
 				(request->actual < request->length)) {
-- 
cgit v1.2.3