On Fri, Feb 20, 2009 at 11:32:24PM +0300, Sergei Shtylyov wrote:
> The MUSB code either expects TXCSR.DMAReqEnab bit cleared in several places
> and then proceeds with clearing the TXCSR.DMAMode bit (but does not bother
> with actually clearing DMAReqEnab beforehand) or just clears both bits at
> once -- while is the programming guide explicitly forbids to clear DMAMode
> before or in the same cycle as DMAReEnab. Fix this and while at it:
>
> - in musb_gadget::txstate(), stop clearing the AutoSet and DMAReqMode bits for
> the CPPI case since they never get set anyway (the former bit is reserved on
> DaVinci) but do clear the DMAReqEnab bit on the DMA error path;
>
> - in musb_host::musb_ep_program(), remove the duplicate DMA controller specific
> code code clearing the TXCSR previous state, add the code to clear TXCSR DMA
> bits on the Inventra DMA error path, to replace such code (executed late) on
> the PIO path;
>
> - in musbhsdma::dma_channel_abort()/dma_controller_irq(), add/use the 'offset'
> variable to avoid MUSB_EP_OFFSET() invocations on every RXCSR/TXCSR access.
>
> Signed-off-by: Sergei Shtylyov <sshtylyov@xxxxxxxxxxxxx>
I ran into the same issue and had to fix similarly, the patch still in
my "nokia-only" queue. Good that you're pushing your version out :-)
just one comment below
> Index: linux-2.6/drivers/usb/musb/musb_gadget.c
> ===================================================================
> --- linux-2.6.orig/drivers/usb/musb/musb_gadget.c
> +++ linux-2.6/drivers/usb/musb/musb_gadget.c
> @@ -165,9 +165,19 @@ static void nuke(struct musb_ep *ep, con
> if (is_dma_capable() && ep->dma) {
> struct dma_controller *c = ep->musb->dma_controller;
> int value;
> +
> if (ep->is_in) {
> + u16 txcsr = musb_readw(epio, MUSB_TXCSR);
this looks unnecessary, in the end you just wanna keep FLUSHFIFO set
so...
> +
> + /*
> + * The programming guide says that we must not clear
> + * the DMAReqMode bit before DMAReqEnab, so we only
> + * clear it in the second write...
> + */
> + txcsr &= MUSB_TXCSR_DMAMODE;
> +
> musb_writew(epio, MUSB_TXCSR,
> - 0 | MUSB_TXCSR_FLUSHFIFO);
> + txcsr | MUSB_TXCSR_FLUSHFIFO);
musb_writew(epio, MUSB_TXCSR,
0 | MUSB_TXCSR_DMAMODE | MUSB_TXCSR_FLUSHFIFO);
musb_writew(epio, MUSB_TXCSR, 0 | MUSB_TXCSR_FLUSHFIFO);
should do it.
--
balbi
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