Hello.
Gupta, Ajay Kumar wrote:
-----Original Message-----
From: Sergei Shtylyov [mailto:sshtylyov@xxxxxxxxxxxxx]
Sent: Friday, August 28, 2009 2:53 PM
To: Gupta, Ajay Kumar
Cc: linux-usb@xxxxxxxxxxxxxxx; linux-omap@xxxxxxxxxxxxxxx;
felipe.balbi@xxxxxxxxx; david-b@xxxxxxxxxxx; Subbrathnam, Swaminathan; B,
Ravi
Subject: Re: [PATCH] musb: fix ISOC Tx programming for CPPI DMAs
Hello.
Ajay Kumar Gupta wrote:
Isochronous Tx DMA is getting programmed but never getting started
for CPPI and TUSB DMAs and thus Isochronous Tx doesn't work.
That's not true.
We have tested and it doesn't work with current driver. Have you tested it and was it working for you ?
Not with the current driver, I must admit. I'll try it today...
diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c
index cf94511..e3ab40a 100644
--- a/drivers/usb/musb/musb_host.c
+++ b/drivers/usb/musb/musb_host.c
@@ -1301,8 +1301,11 @@ void musb_host_tx(struct musb *musb, u8 epnum)
return;
} else if (usb_pipeisoc(pipe) && dma) {
if (musb_tx_dma_program(musb->dma_controller, hw_ep, qh, urb,
- offset, length))
+ offset, length)) {
+ if (is_cppi_enabled() || tusb_dma_omap())
+ musb_h_tx_dma_start(hw_ep);
return;
It will have been already started by this moment -- from
musb_start_urb() which is enough . Otherwise it wouldn't work, and I've
made sure it *does* work.
This part is being done at musb_host_rx()
You're doing it in musb_host_tx() actually. Although musb_host_rx()
is also broken WRT the isochronous transfers.
doing next packet programming within same urb and *not* starting next urb. Thus musb_start_urb() doesn't come into this path.
What? Read the code, please -- musb_start_urb() call should always
precede musb_host_tx() which handles the DMA interrupt. Unless something
clears DMAReqEnab after musb_start_urb() call, setting it only once
should work.
So it wouldn't start the DMAs.
How musb_host_tx() can be called without musb_start_urb()?
In case of PIO, it does load the FIFO and sets the TXPKTREADY.
Only is URB_ISO_ASAP is not set.
WBR, Sergei
-Ajay
WBR, Sergei
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