Hello.
Nicolas Boichat wrote:
This patch fixes isochronous short packets (i.e., length< maximum packet
size) handling in the MUSB driver, when the Inventra DMA engine is active.
It is based on this tree:
http://arago-project.org/git/people/sriram/ti-psp-omap.git?p=people/sriram/ti-psp-omap.git;a=shortlog;h=refs/heads/OMAPPSP_03.00.02.07
but seems to apply cleanly against a 2.6.35-rc5 kernel (untested though).
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
transfered correctly, but multiple requests were often put together in one
USB packet, which I believe should not be done, 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.
A more complete description is available at
http://beagleboard-usbsniffer.blogspot.com/2010/07/musb-isochronous-transfers-fixed.html
and the gadgetfs driver used to reproduce the problem is available at
http://elinux.org/BeagleBoard/GSoC/USBSniffer#MUSB_testing_code .
Signed-off-by: Nicolas Boichat<nicolas@xxxxxxxxxx>
[...]
diff --git a/drivers/usb/musb/musb_gadget.c
b/drivers/usb/musb/musb_gadget.c
index 82bcb0d..eea05e5 100644
--- a/drivers/usb/musb/musb_gadget.c
+++ b/drivers/usb/musb/musb_gadget.c
@@ -495,18 +495,23 @@ void musb_g_tx(struct musb *musb, u8 epnum)
}
if (is_dma || request->actual == request->length) {
+#ifdef CONFIG_USB_INVENTRA_DMA
+ if (is_dma&& (!dma->desired_mode ||
Your mailer converts tabs to spaces and does some strange things with &
and spaces too.
WBR, Sergei
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