Fixes endpoint starvation issue when more than one bulk QH is multiplexed on the reserved bulk TX endpoint. This patch sets the NAK timeout interval for such QHs, and when a timeout triggers the next QH will be scheduled. This scheme doesn't work for devices which are connected to a high to full speed tree (transaction translator) as there is no NAK timeout interrupt from the musb controller from such devices. Signed-off-by: Ajay Kumar Gupta <ajay.gupta@xxxxxx> --- This patch is adding a new feature and created against today's linus's tree. drivers/usb/musb/musb_host.c | 154 +++++++++++++++++++++++++----------------- 1 files changed, 92 insertions(+), 62 deletions(-) diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c index e090c79..338947c 100644 --- a/drivers/usb/musb/musb_host.c +++ b/drivers/usb/musb/musb_host.c @@ -882,6 +882,73 @@ static void musb_ep_program(struct musb *musb, u8 epnum, } } +/* Schedule next QH from musb->in_bulk/out_bulk and move the current qh to + * the end; avoids starvation for other endpoints. + */ +static void musb_bulk_nak_timeout(struct musb *musb, struct musb_hw_ep *ep, + int is_in) +{ + struct dma_channel *dma; + struct urb *urb; + void __iomem *mbase = musb->mregs; + void __iomem *epio = ep->regs; + struct musb_qh *cur_qh, *next_qh; + u16 rx_csr, tx_csr; + + musb_ep_select(mbase, ep->epnum); + if (is_in) { + dma = is_dma_capable() ? ep->rx_channel : NULL; + + /* clear nak timeout bit */ + rx_csr = musb_readw(epio, MUSB_RXCSR); + rx_csr |= MUSB_RXCSR_H_WZC_BITS; + rx_csr &= ~MUSB_RXCSR_DATAERROR; + musb_writew(epio, MUSB_RXCSR, rx_csr); + + cur_qh = first_qh(&musb->in_bulk); + } else { + dma = is_dma_capable() ? ep->tx_channel : NULL; + + /* clear nak timeout bit */ + tx_csr = musb_readw(epio, MUSB_TXCSR); + tx_csr |= MUSB_TXCSR_H_WZC_BITS; + tx_csr &= ~MUSB_TXCSR_H_NAKTIMEOUT; + musb_writew(epio, MUSB_TXCSR, tx_csr); + + cur_qh = first_qh(&musb->out_bulk); + } + if (cur_qh) { + urb = next_urb(cur_qh); + if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) { + dma->status = MUSB_DMA_STATUS_CORE_ABORT; + musb->dma_controller->channel_abort(dma); + urb->actual_length += dma->actual_len; + dma->actual_len = 0L; + } + musb_save_toggle(cur_qh, is_in, urb); + + if (is_in) { + /* move cur_qh to end of queue */ + list_move_tail(&cur_qh->ring, &musb->in_bulk); + + /* get the next qh from musb->in_bulk */ + next_qh = first_qh(&musb->in_bulk); + + /* set rx_reinit and schedule the next qh */ + ep->rx_reinit = 1; + } else { + /* move cur_qh to end of queue */ + list_move_tail(&cur_qh->ring, &musb->out_bulk); + + /* get the next qh from musb->out_bulk */ + next_qh = first_qh(&musb->out_bulk); + + /* set tx_reinit and schedule the next qh */ + ep->tx_reinit = 1; + } + musb_start_urb(musb, is_in, next_qh); + } +} /* * Service the default endpoint (ep0) as host. @@ -1146,21 +1213,28 @@ void musb_host_tx(struct musb *musb, u8 epnum) status = -ETIMEDOUT; } else if (tx_csr & MUSB_TXCSR_H_NAKTIMEOUT) { - dev_dbg(musb->controller, "TX end=%d device not responding\n", epnum); - - /* NOTE: this code path would be a good place to PAUSE a - * transfer, if there's some other (nonperiodic) tx urb - * that could use this fifo. (dma complicates it...) - * That's already done for bulk RX transfers. - * - * if (bulk && qh->ring.next != &musb->out_bulk), then - * we have a candidate... NAKing is *NOT* an error - */ - musb_ep_select(mbase, epnum); - musb_writew(epio, MUSB_TXCSR, - MUSB_TXCSR_H_WZC_BITS - | MUSB_TXCSR_TXPKTRDY); - return; + if (USB_ENDPOINT_XFER_BULK == qh->type && qh->mux == 1 + && !list_is_singular(&musb->out_bulk)) { + dev_dbg(musb->controller, + "NAK timeout on TX%d ep\n", epnum); + musb_bulk_nak_timeout(musb, hw_ep, 0); + } else { + dev_dbg(musb->controller, + "TX end=%d device not responding\n", epnum); + /* NOTE: this code path would be a good place to PAUSE a + * transfer, if there's some other (nonperiodic) tx urb + * that could use this fifo. (dma complicates it...) + * That's already done for bulk RX transfers. + * + * if (bulk && qh->ring.next != &musb->out_bulk), then + * we have a candidate... NAKing is *NOT* an error + */ + musb_ep_select(mbase, epnum); + musb_writew(epio, MUSB_TXCSR, + MUSB_TXCSR_H_WZC_BITS + | MUSB_TXCSR_TXPKTRDY); + } + return; } if (status) { @@ -1380,50 +1454,6 @@ void musb_host_tx(struct musb *musb, u8 epnum) #endif -/* Schedule next QH from musb->in_bulk and move the current qh to - * the end; avoids starvation for other endpoints. - */ -static void musb_bulk_rx_nak_timeout(struct musb *musb, struct musb_hw_ep *ep) -{ - struct dma_channel *dma; - struct urb *urb; - void __iomem *mbase = musb->mregs; - void __iomem *epio = ep->regs; - struct musb_qh *cur_qh, *next_qh; - u16 rx_csr; - - musb_ep_select(mbase, ep->epnum); - dma = is_dma_capable() ? ep->rx_channel : NULL; - - /* clear nak timeout bit */ - rx_csr = musb_readw(epio, MUSB_RXCSR); - rx_csr |= MUSB_RXCSR_H_WZC_BITS; - rx_csr &= ~MUSB_RXCSR_DATAERROR; - musb_writew(epio, MUSB_RXCSR, rx_csr); - - cur_qh = first_qh(&musb->in_bulk); - if (cur_qh) { - urb = next_urb(cur_qh); - if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) { - dma->status = MUSB_DMA_STATUS_CORE_ABORT; - musb->dma_controller->channel_abort(dma); - urb->actual_length += dma->actual_len; - dma->actual_len = 0L; - } - musb_save_toggle(cur_qh, 1, urb); - - /* move cur_qh to end of queue */ - list_move_tail(&cur_qh->ring, &musb->in_bulk); - - /* get the next qh from musb->in_bulk */ - next_qh = first_qh(&musb->in_bulk); - - /* set rx_reinit and schedule the next qh */ - ep->rx_reinit = 1; - musb_start_urb(musb, 1, next_qh); - } -} - /* * Service an RX interrupt for the given IN endpoint; docs cover bulk, iso, * and high-bandwidth IN transfer cases. @@ -1500,7 +1530,7 @@ void musb_host_rx(struct musb *musb, u8 epnum) if (usb_pipebulk(urb->pipe) && qh->mux == 1 && !list_is_singular(&musb->in_bulk)) { - musb_bulk_rx_nak_timeout(musb, hw_ep); + musb_bulk_nak_timeout(musb, hw_ep, 1); return; } musb_ep_select(mbase, epnum); @@ -1859,14 +1889,14 @@ static int musb_schedule( else head = &musb->out_bulk; - /* Enable bulk RX NAK timeout scheme when bulk requests are + /* Enable bulk RX/TX NAK timeout scheme when bulk requests are * multiplexed. This scheme doen't work in high speed to full * speed scenario as NAK interrupts are not coming from a * full speed device connected to a high speed device. * NAK timeout interval is 8 (128 uframe or 16ms) for HS and * 4 (8 frame or 8ms) for FS device. */ - if (is_in && qh->dev) + if (qh->dev) qh->intv_reg = (USB_SPEED_HIGH == qh->dev->speed) ? 8 : 4; goto success; -- 1.7.0.4 -- 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