Hi,
>-----Original Message-----
>From: Gupta, Ajay Kumar
>Sent: Friday, May 14, 2010 10:51 AM
>To: Kalliguddi, Hema; linux-usb@xxxxxxxxxxxxxxx
>Cc: Kalliguddi, Hema; Felipe Balbi
>Subject: RE: musb: unmap the DMA buffer when switching to PIO mode
>
>Hi,
>> From: Hema HK <hemahk@xxxxxx>
>>
>> Buffer is mapped to dma when dma channel is allocated. Buffer needs
>> to be unmapped when fallback to cpu mode if dma channel_program
>> fails.
>>
>> Signed-off-by: Hema HK <hemahk@xxxxxx>
>> Cc: Felipe Balbi <felipe.balbi@xxxxxxxxx>
>> ---
>>
>> 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
>> @@ -120,22 +120,24 @@ __acquires(ep->musb->lock)
>> ep->busy = 1;
>> spin_unlock(&musb->lock);
>> if (is_dma_capable()) {
>> - if (req->mapped) {
>> - dma_unmap_single(musb->controller,
>> - req->request.dma,
>> - req->request.length,
>> - req->tx
>> - ? DMA_TO_DEVICE
>> - : DMA_FROM_DEVICE);
>> - req->request.dma = DMA_ADDR_INVALID;
>> - req->mapped = 0;
>> - } else if (req->request.dma != DMA_ADDR_INVALID)
>> - dma_sync_single_for_cpu(musb->controller,
>> - req->request.dma,
>> - req->request.length,
>> - req->tx
>> - ? DMA_TO_DEVICE
>> - : DMA_FROM_DEVICE);
>> + if (req->request.dma != DMA_ADDR_INVALID) {
>> + if (req->mapped) {
>> + dma_unmap_single(musb->controller,
>> + req->request.dma,
>> + req->request.length,
>> + req->tx
>> + ? DMA_TO_DEVICE
>> + :
>DMA_FROM_DEVICE);
>> + req->request.dma = DMA_ADDR_INVALID;
>> + req->mapped = 0;
>> + } else if (req->request.dma != DMA_ADDR_INVALID)
>
>Here 'if' condition check not required.
Agree. I will remove in the next version of the patch.
>
>> +
>dma_sync_single_for_cpu(musb->controller,
>> + req->request.dma,
>> + req->request.length,
>> + req->tx
>> + ? DMA_TO_DEVICE
>> + :
>DMA_FROM_DEVICE);
>> + }
>> }
>> if (request->status == 0)
>> DBG(5, "%s done request %p, %d/%d\n",
>> @@ -393,6 +395,29 @@ static void txstate(struct musb *musb, s
>> #endif
>>
>> if (!use_dma) {
>> + /* unmap the dma buffer back to cpu if dma channel
>> + *programming fails
>
>Need speace before '*'. Please run checkpatch.pl on your patch
>to catch these errors.
I will correct this.
>
>> + */
>> + if (is_dma_capable()) {
>> + if (req->mapped) {
>> + dma_unmap_single(musb->controller,
>> + req->request.dma,
>> + req->request.length,
>> + req->tx
>> + ? DMA_TO_DEVICE
>> + : DMA_FROM_DEVICE);
>> + req->request.dma = DMA_ADDR_INVALID;
>> + req->mapped = 0;
>> + } else if (req->request.dma !=
>DMA_ADDR_INVALID) {
>> +
>dma_sync_single_for_cpu(musb->controller,
>> + req->request.dma,
>> + req->request.length,
>> + req->tx
>> + ? DMA_TO_DEVICE
>> + : DMA_FROM_DEVICE);
>
>We are already in 'rxstate' so why this check ?
Yes it can be removed. But as per your other comment this code is
being moved to inline function so this check will be still existing.
>
>> + }
>> + }
>> +
>> musb_write_fifo(musb_ep->hw_ep, fifo_count,
>> (u8 *) (request->buf +
>request->actual));
>> request->actual += fifo_count;
>> @@ -711,7 +736,31 @@ static void rxstate(struct musb *musb, s
>> return;
>> }
>> #endif
>> -
>> + /* unmap the dma buffer back to cpu if dma channel
>> + * programming fails. This buffer is mapped if
>the channel
>> + * allocation is successful
>> + */
>> + if (is_dma_capable()) {
>> + if (req->mapped) {
>> +
>dma_unmap_single(musb->controller,
>> + req->request.dma,
>> + req->request.length,
>> + req->tx
>> + ? DMA_TO_DEVICE
>> + :
>DMA_FROM_DEVICE);
>> + req->request.dma =
>DMA_ADDR_INVALID;
>> + req->mapped = 0;
>> + } else if (req->request.dma !=
>> + DMA_ADDR_INVALID) {
>> + dma_sync_single_for_cpu(
>> + musb->controller,
>> + req->request.dma,
>> + req->request.length,
>> + req->tx
>> + ? DMA_TO_DEVICE
>> + :
>DMA_FROM_DEVICE);
>We are already in 'txstate' so why this check?
>Instead of repeating this whole block, it's better to use some
>function.
Yes it can be removed. But this code be moved to inline function
so this check will be still existing.
~Hema
>-Ajay
>> + }
>> + }
>
>
>> musb_read_fifo(musb_ep->hw_ep,
>fifo_count, (u8 *)
>> (request->buf +
>request->actual));
>> request->actual += fifo_count;
>> --
>> To unsubscribe from this list: send the line "unsubscribe
>linux-usb" in
>> the body of a message to majordomo@xxxxxxxxxxxxxxx
>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
