From: Hema Kalliguddi <hemahk@xxxxxx> Buffer is mapped to dma when dma channel is allocated. If, for some reason, dma channel programming fails, musb code will fallback to PIO mode to transfer that request. In that case, we need to unmap the buffer back to CPU. MUSB RTL1.8 and above cannot handle buffers which are not 32bit aligned. That happens to every request sent by g_ether gadget driver. Since the buffer sent was unaligned, we need to fallback to PIO. Because of that, g_ether was failing due to missing buffer unmapping. With this patch and [1] g_ether works fine with all MUSB revisions. Verified with OMAP3630 board, which has MUSB RTL1.8 using g_ether and g_zero. [1] http://www.spinics.net/lists/linux-usb/msg38400.html Signed-off-by: Hema HK <hemahk@xxxxxx> Signed-off-by: Felipe Balbi <balbi@xxxxxx> --- drivers/usb/musb/musb_gadget.c | 117 +++++++++++++++++++++++++++------------- 1 files changed, 79 insertions(+), 38 deletions(-) diff --git a/drivers/usb/musb/musb_gadget.c b/drivers/usb/musb/musb_gadget.c index 36cfd06..0169dcf 100644 --- a/drivers/usb/musb/musb_gadget.c +++ b/drivers/usb/musb/musb_gadget.c @@ -92,6 +92,59 @@ /* ----------------------------------------------------------------------- */ +/* Maps the buffer to dma */ + +static inline void map_dma_buffer(struct musb_request *request, + struct musb *musb) +{ + if (request->request.dma == DMA_ADDR_INVALID) { + request->request.dma = dma_map_single( + musb->controller, + request->request.buf, + request->request.length, + request->tx + ? DMA_TO_DEVICE + : DMA_FROM_DEVICE); + request->mapped = 1; + } else { + dma_sync_single_for_device(musb->controller, + request->request.dma, + request->request.length, + request->tx + ? DMA_TO_DEVICE + : DMA_FROM_DEVICE); + request->mapped = 0; + } +} + +/* Unmap the buffer from dma and maps it back to cpu */ +static inline void unmap_dma_buffer(struct musb_request *request, + struct musb *musb) +{ + if (request->request.dma == DMA_ADDR_INVALID) { + DBG(20, "not unmapping a never mapped buffer\n"); + return; + } + if (request->mapped) { + dma_unmap_single(musb->controller, + request->request.dma, + request->request.length, + request->tx + ? DMA_TO_DEVICE + : DMA_FROM_DEVICE); + request->request.dma = DMA_ADDR_INVALID; + request->mapped = 0; + } else { + dma_sync_single_for_cpu(musb->controller, + request->request.dma, + request->request.length, + request->tx + ? DMA_TO_DEVICE + : DMA_FROM_DEVICE); + + } +} + /* * Immediately complete a request. * @@ -119,24 +172,8 @@ __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 (is_dma_capable() && ep->dma) + unmap_dma_buffer(req, musb); if (request->status == 0) DBG(5, "%s done request %p, %d/%d\n", ep->end_point.name, request, @@ -395,6 +432,13 @@ static void txstate(struct musb *musb, struct musb_request *req) #endif if (!use_dma) { + /* + * Unmap the dma buffer back to cpu if dma channel + * programming fails + */ + if (is_dma_capable() && musb_ep->dma) + unmap_dma_buffer(req, musb); + musb_write_fifo(musb_ep->hw_ep, fifo_count, (u8 *) (request->buf + request->actual)); request->actual += fifo_count; @@ -713,6 +757,20 @@ static void rxstate(struct musb *musb, struct musb_request *req) 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() && musb_ep->dma) { + unmap_dma_buffer(req, musb); + + /* Clear DMAENAB for the + * PIO mode transfer + */ + csr &= ~MUSB_RXCSR_DMAENAB; + musb_writew(epio, MUSB_RXCSR, csr); + } musb_read_fifo(musb_ep->hw_ep, fifo_count, (u8 *) (request->buf + request->actual)); @@ -1150,26 +1208,9 @@ static int musb_gadget_queue(struct usb_ep *ep, struct usb_request *req, request->epnum = musb_ep->current_epnum; request->tx = musb_ep->is_in; - if (is_dma_capable() && musb_ep->dma) { - if (request->request.dma == DMA_ADDR_INVALID) { - request->request.dma = dma_map_single( - musb->controller, - request->request.buf, - request->request.length, - request->tx - ? DMA_TO_DEVICE - : DMA_FROM_DEVICE); - request->mapped = 1; - } else { - dma_sync_single_for_device(musb->controller, - request->request.dma, - request->request.length, - request->tx - ? DMA_TO_DEVICE - : DMA_FROM_DEVICE); - request->mapped = 0; - } - } else + if (is_dma_capable() && musb_ep->dma) + map_dma_buffer(request, musb); + else request->mapped = 0; spin_lock_irqsave(&musb->lock, lockflags); -- 1.7.1 -- 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
