diff mbox series

[v2] usb: gadget: musb: fix short isoc packets with inventra dma

Message ID 20190130141321.3500-1-b-liu@ti.com (mailing list archive)
State Mainlined
Commit c418fd6c01fbc5516a2cd1eaf1df1ec86869028a
Headers show
Series [v2] usb: gadget: musb: fix short isoc packets with inventra dma | expand

Commit Message

Bin Liu Jan. 30, 2019, 2:13 p.m. UTC 
From: Paul Elder <paul.elder@ideasonboard.com>

Handling short packets (length < max packet size) in the Inventra DMA
engine in the MUSB driver causes the MUSB DMA controller to hang. An
example of a problem that is caused by this problem is when streaming
video out of a UVC gadget, only the first video frame is transferred.

For short packets (mode-0 or mode-1 DMA), MUSB_TXCSR_TXPKTRDY must be
set manually by the driver. This was previously done in musb_g_tx
(musb_gadget.c), but incorrectly (all csr flags were cleared, and only
MUSB_TXCSR_MODE and MUSB_TXCSR_TXPKTRDY were set). Fixing that problem
allows some requests to be transferred correctly, but multiple requests
were often put together in one USB packet, and caused problems if the
packet size was not a multiple of 4. Instead, set MUSB_TXCSR_TXPKTRDY
in dma_controller_irq (musbhsdma.c), just like host mode transfers.

This topic was originally tackled by Nicolas Boichat [0] [1] and is
discussed further at [2] as part of his GSoC project [3].

[0] https://groups.google.com/forum/?hl=en#!topic/beagleboard-gsoc/k8Azwfp75CU
[1] https://gitorious.org/beagleboard-usbsniffer/beagleboard-usbsniffer-kernel/commit/b0be3b6cc195ba732189b04f1d43ec843c3e54c9?p=beagleboard-usbsniffer:beagleboard-usbsniffer-kernel.git;a=patch;h=b0be3b6cc195ba732189b04f1d43ec843c3e54c9
[2] http://beagleboard-usbsniffer.blogspot.com/2010/07/musb-isochronous-transfers-fixed.html
[3] http://elinux.org/BeagleBoard/GSoC/USBSniffer

Fixes: 550a7375fe72 ("USB: Add MUSB and TUSB support")
Signed-off-by: Paul Elder <paul.elder@ideasonboard.com>
Signed-off-by: Bin Liu <b-liu@ti.com>
---
v2: add Fixes tag.

 drivers/usb/musb/musb_gadget.c | 13 +------------
 drivers/usb/musb/musbhsdma.c   | 21 +++++++++++----------
 2 files changed, 12 insertions(+), 22 deletions(-)

Comments

Greg KH Jan. 30, 2019, 2:49 p.m. UTC | #1 
On Wed, Jan 30, 2019 at 08:13:21AM -0600, Bin Liu wrote:
> From: Paul Elder <paul.elder@ideasonboard.com>
> 
> Handling short packets (length < max packet size) in the Inventra DMA
> engine in the MUSB driver causes the MUSB DMA controller to hang. An
> example of a problem that is caused by this problem is when streaming
> video out of a UVC gadget, only the first video frame is transferred.
> 
> For short packets (mode-0 or mode-1 DMA), MUSB_TXCSR_TXPKTRDY must be
> set manually by the driver. This was previously done in musb_g_tx
> (musb_gadget.c), but incorrectly (all csr flags were cleared, and only
> MUSB_TXCSR_MODE and MUSB_TXCSR_TXPKTRDY were set). Fixing that problem
> allows some requests to be transferred correctly, but multiple requests
> were often put together in one USB packet, and caused problems if the
> packet size was not a multiple of 4. Instead, set MUSB_TXCSR_TXPKTRDY
> in dma_controller_irq (musbhsdma.c), just like host mode transfers.
> 
> This topic was originally tackled by Nicolas Boichat [0] [1] and is
> discussed further at [2] as part of his GSoC project [3].
> 
> [0] https://groups.google.com/forum/?hl=en#!topic/beagleboard-gsoc/k8Azwfp75CU
> [1] https://gitorious.org/beagleboard-usbsniffer/beagleboard-usbsniffer-kernel/commit/b0be3b6cc195ba732189b04f1d43ec843c3e54c9?p=beagleboard-usbsniffer:beagleboard-usbsniffer-kernel.git;a=patch;h=b0be3b6cc195ba732189b04f1d43ec843c3e54c9
> [2] http://beagleboard-usbsniffer.blogspot.com/2010/07/musb-isochronous-transfers-fixed.html
> [3] http://elinux.org/BeagleBoard/GSoC/USBSniffer
> 
> Fixes: 550a7375fe72 ("USB: Add MUSB and TUSB support")
> Signed-off-by: Paul Elder <paul.elder@ideasonboard.com>
> Signed-off-by: Bin Liu <b-liu@ti.com>
> Cc: stable <stable@vger.kernel.org>
> ---
> v2: add Fixes tag.

I added a stable tag so that you get notified by my scripts if/when it
fails to apply.  Otherwise Sasha's scripts are going to try to evaluate
it and determine if this needs to be backported or not, and we already
know that it does need to be, so let's not waste their time.

thanks,

greg k-h
Bin Liu Jan. 30, 2019, 3:15 p.m. UTC | #2 
On Wed, Jan 30, 2019 at 03:49:26PM +0100, Greg Kroah-Hartman wrote:
> On Wed, Jan 30, 2019 at 08:13:21AM -0600, Bin Liu wrote:
> > From: Paul Elder <paul.elder@ideasonboard.com>
> > 
> > Handling short packets (length < max packet size) in the Inventra DMA
> > engine in the MUSB driver causes the MUSB DMA controller to hang. An
> > example of a problem that is caused by this problem is when streaming
> > video out of a UVC gadget, only the first video frame is transferred.
> > 
> > For short packets (mode-0 or mode-1 DMA), MUSB_TXCSR_TXPKTRDY must be
> > set manually by the driver. This was previously done in musb_g_tx
> > (musb_gadget.c), but incorrectly (all csr flags were cleared, and only
> > MUSB_TXCSR_MODE and MUSB_TXCSR_TXPKTRDY were set). Fixing that problem
> > allows some requests to be transferred correctly, but multiple requests
> > were often put together in one USB packet, and caused problems if the
> > packet size was not a multiple of 4. Instead, set MUSB_TXCSR_TXPKTRDY
> > in dma_controller_irq (musbhsdma.c), just like host mode transfers.
> > 
> > This topic was originally tackled by Nicolas Boichat [0] [1] and is
> > discussed further at [2] as part of his GSoC project [3].
> > 
> > [0] https://groups.google.com/forum/?hl=en#!topic/beagleboard-gsoc/k8Azwfp75CU
> > [1] https://gitorious.org/beagleboard-usbsniffer/beagleboard-usbsniffer-kernel/commit/b0be3b6cc195ba732189b04f1d43ec843c3e54c9?p=beagleboard-usbsniffer:beagleboard-usbsniffer-kernel.git;a=patch;h=b0be3b6cc195ba732189b04f1d43ec843c3e54c9
> > [2] http://beagleboard-usbsniffer.blogspot.com/2010/07/musb-isochronous-transfers-fixed.html
> > [3] http://elinux.org/BeagleBoard/GSoC/USBSniffer
> > 
> > Fixes: 550a7375fe72 ("USB: Add MUSB and TUSB support")
> > Signed-off-by: Paul Elder <paul.elder@ideasonboard.com>
> > Signed-off-by: Bin Liu <b-liu@ti.com>
> > Cc: stable <stable@vger.kernel.org>
> > ---
> > v2: add Fixes tag.
> 
> I added a stable tag so that you get notified by my scripts if/when it
> fails to apply.  Otherwise Sasha's scripts are going to try to evaluate
> it and determine if this needs to be backported or not, and we already
> know that it does need to be, so let's not waste their time.

Sounds good. Thanks.

I track those musb patches which require manual backport - it doesn't
happen very often. But since You and Sasha already have an automation to
take care of the tasks, I from now on will add 'cc: stable' whenever
applicable and let the scripts to alert me when any action is needed.

Regards,
-Bin.
diff mbox series

Patch

diff --git a/drivers/usb/musb/musb_gadget.c b/drivers/usb/musb/musb_gadget.c
index eae8b1b1b45b..ffe462a657b1 100644
--- a/drivers/usb/musb/musb_gadget.c
+++ b/drivers/usb/musb/musb_gadget.c
@@ -452,13 +452,10 @@  void musb_g_tx(struct musb *musb, u8 epnum)
 	}
 
 	if (request) {
-		u8	is_dma = 0;
-		bool	short_packet = false;
 
 		trace_musb_req_tx(req);
 
 		if (dma && (csr & MUSB_TXCSR_DMAENAB)) {
-			is_dma = 1;
 			csr |= MUSB_TXCSR_P_WZC_BITS;
 			csr &= ~(MUSB_TXCSR_DMAENAB | MUSB_TXCSR_P_UNDERRUN |
 				 MUSB_TXCSR_TXPKTRDY | MUSB_TXCSR_AUTOSET);
@@ -476,16 +473,8 @@  void musb_g_tx(struct musb *musb, u8 epnum)
 		 */
 		if ((request->zero && request->length)
 			&& (request->length % musb_ep->packet_sz == 0)
-			&& (request->actual == request->length))
-				short_packet = true;
+			&& (request->actual == request->length)) {
 
-		if ((musb_dma_inventra(musb) || musb_dma_ux500(musb)) &&
-			(is_dma && (!dma->desired_mode ||
-				(request->actual &
-					(musb_ep->packet_sz - 1)))))
-				short_packet = true;
-
-		if (short_packet) {
 			/*
 			 * On DMA completion, FIFO may not be
 			 * available yet...
diff --git a/drivers/usb/musb/musbhsdma.c b/drivers/usb/musb/musbhsdma.c
index a688f7f87829..5fc6825745f2 100644
--- a/drivers/usb/musb/musbhsdma.c
+++ b/drivers/usb/musb/musbhsdma.c
@@ -346,12 +346,10 @@  static irqreturn_t dma_controller_irq(int irq, void *private_data)
 				channel->status = MUSB_DMA_STATUS_FREE;
 
 				/* completed */
-				if ((devctl & MUSB_DEVCTL_HM)
-					&& (musb_channel->transmit)
-					&& ((channel->desired_mode == 0)
-					    || (channel->actual_len &
-					    (musb_channel->max_packet_sz - 1)))
-				    ) {
+				if (musb_channel->transmit &&
+					(!channel->desired_mode ||
+					(channel->actual_len %
+					    musb_channel->max_packet_sz))) {
 					u8  epnum  = musb_channel->epnum;
 					int offset = musb->io.ep_offset(epnum,
 								    MUSB_TXCSR);
@@ -363,11 +361,14 @@  static irqreturn_t dma_controller_irq(int irq, void *private_data)
 					 */
 					musb_ep_select(mbase, epnum);
 					txcsr = musb_readw(mbase, offset);
-					txcsr &= ~(MUSB_TXCSR_DMAENAB
+					if (channel->desired_mode == 1) {
+						txcsr &= ~(MUSB_TXCSR_DMAENAB
 							| MUSB_TXCSR_AUTOSET);
-					musb_writew(mbase, offset, txcsr);
-					/* Send out the packet */
-					txcsr &= ~MUSB_TXCSR_DMAMODE;
+						musb_writew(mbase, offset, txcsr);
+						/* Send out the packet */
+						txcsr &= ~MUSB_TXCSR_DMAMODE;
+						txcsr |= MUSB_TXCSR_DMAENAB;
+					}
 					txcsr |=  MUSB_TXCSR_TXPKTRDY;
 					musb_writew(mbase, offset, txcsr);
 				}