Hi Paul, Sorry for the delay on reviewing it. For the subject, can you please use usb: musb: gadget: fix short isoc packets with inventra dma On Tue, Oct 09, 2018 at 02:32:20AM -0400, Paul Elder wrote: > 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). 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, MUSB_TXCSR_TXPKTRDY is set in dma_controller_irq (musbhsdma.c), > just like host mode transfers, then musb_g_tx forces the packet to be > flushed, by setting MUSB_TXCSR_FLUSHFIFO. > > This topic was originally tackled by Nicolas Boichat [0] [1] and is discussed this line is longer than 75 chars. > 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 > > I have forward-ported this patch from 2.6.34 to 4.19-rc1. this line is irrelevant to the commit message, please move it down to under '---'. > > Signed-off-by: Paul Elder <paul.elder@xxxxxxxxxxxxxxxx> > --- > drivers/usb/musb/musb_gadget.c | 21 ++++++++++++++------- > drivers/usb/musb/musbhsdma.c | 21 +++++++++++---------- > 2 files changed, 25 insertions(+), 17 deletions(-) > > diff --git a/drivers/usb/musb/musb_gadget.c b/drivers/usb/musb/musb_gadget.c > index eae8b1b1b45b..d3f33f449445 100644 > --- a/drivers/usb/musb/musb_gadget.c > +++ b/drivers/usb/musb/musb_gadget.c > @@ -479,11 +479,16 @@ void musb_g_tx(struct musb *musb, u8 epnum) > && (request->actual == request->length)) > short_packet = true; > > - 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 (is_dma && (musb_dma_inventra(musb) || musb_dma_ux500(musb))) { more than 80 chars. > + if (!dma->desired_mode || I understand you forward-port Nicolas' patch, but do you have a specific readon to re-write this 'if' condition? I'd like to see minimum code change in bug fixes, > + request->actual % musb_ep->packet_sz) { but I like this version though, easier to read. > + musb_dbg(musb, "%s Flushing (FIFO) EP : KPB\n", what is 'KPB'? the message could be more meaningful? > + musb_ep->end_point.name); > + musb_writew(epio, MUSB_TXCSR, > + csr | MUSB_TXCSR_FLUSHFIFO); What if without this line? The short packet doesn't send out? setting TXSCR_TXPKTRDY in the dma driver is not sufficient? TXSCR_FLUSHFIFO is only used for aborting cases. > + return; > + } > + } > > if (short_packet) { > /* > @@ -493,8 +498,10 @@ void musb_g_tx(struct musb *musb, u8 epnum) > if (csr & MUSB_TXCSR_TXPKTRDY) > return; > > - musb_writew(epio, MUSB_TXCSR, MUSB_TXCSR_MODE > - | MUSB_TXCSR_TXPKTRDY); > + musb_dbg(musb, "sending zero pkt (zero=%d, length=%d, actual=%d, dma->desired_mode=%d)\n", > + request->zero, request->length, request->actual, more than 80 chars. > + dma->desired_mode); > + musb_writew(epio, MUSB_TXCSR, csr | MUSB_TXCSR_TXPKTRDY); more than 80 chars. > request->zero = 0; > } > > diff --git a/drivers/usb/musb/musbhsdma.c b/drivers/usb/musb/musbhsdma.c > index a688f7f87829..e514d4700a6b 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))) { improper indentation. > 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); more than 80 chars. > + /* Send out the packet */ > + txcsr &= ~MUSB_TXCSR_DMAMODE; > + txcsr |= MUSB_TXCSR_DMAENAB; > + } > txcsr |= MUSB_TXCSR_TXPKTRDY; > musb_writew(mbase, offset, txcsr); > } Regards, -Bin.
