*
* - DMA (Mentor/OMAP) ...has at least toggle update problems
*
- * - Still no traffic scheduling code to make NAKing for bulk or control
- * transfers unable to starve other requests; or to make efficient use
- * of hardware with periodic transfers. (Note that network drivers
- * commonly post bulk reads that stay pending for a long time; these
- * would make very visible trouble.)
+ * - [23-feb-2009] minimal traffic scheduling to avoid bulk RX packet
+ * starvation ... nothing yet for TX, interrupt, or bulk.
*
* - Not tested with HNP, but some SRP paths seem to behave.
*
*
* CONTROL transfers all go through ep0. BULK ones go through dedicated IN
* and OUT endpoints ... hardware is dedicated for those "async" queue(s).
- *
* (Yes, bulk _could_ use more of the endpoints than that, and would even
- * benefit from it ... one remote device may easily be NAKing while others
- * need to perform transfers in that same direction. The same thing could
- * be done in software though, assuming dma cooperates.)
+ * benefit from it.)
*
* INTERUPPT and ISOCHRONOUS transfers are scheduled to the other endpoints.
* So far that scheduling is both dumb and optimistic: the endpoint will be
len = urb->iso_frame_desc[0].length;
break;
default: /* bulk, interrupt */
- buf = urb->transfer_buffer;
- len = urb->transfer_buffer_length;
+ /* actual_length may be nonzero on retry paths */
+ buf = urb->transfer_buffer + urb->actual_length;
+ len = urb->transfer_buffer_length - urb->actual_length;
}
DBG(4, "qh %p urb %p dev%d ep%d%s%s, hw_ep %d, %p/%d\n",
/* NOTE: this code path would be a good place to PAUSE a
* control transfer, if another one is queued, so that
- * ep0 is more likely to stay busy.
+ * ep0 is more likely to stay busy. That's already done
+ * for bulk RX transfers.
*
* if (qh->ring.next != &musb->control), then
* we have a candidate... NAKing is *NOT* an error
/* 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
#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(ep, 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.
} else if (rx_csr & MUSB_RXCSR_DATAERROR) {
if (USB_ENDPOINT_XFER_ISOC != qh->type) {
- /* NOTE this code path would be a good place to PAUSE a
- * transfer, if there's some other (nonperiodic) rx urb
- * that could use this fifo. (dma complicates it...)
+ DBG(6, "RX end %d NAK timeout\n", epnum);
+
+ /* NOTE: NAKing is *NOT* an error, so we want to
+ * continue. Except ... if there's a request for
+ * another QH, use that instead of starving it.
*
- * if (bulk && qh->ring.next != &musb->in_bulk), then
- * we have a candidate... NAKing is *NOT* an error
+ * Devices like Ethernet and serial adapters keep
+ * reads posted at all times, which will starve
+ * other devices without this logic.
*/
- DBG(6, "RX end %d NAK timeout\n", epnum);
+ if (usb_pipebulk(urb->pipe)
+ && qh->mux == 1
+ && !list_is_singular(&musb->in_bulk)) {
+ musb_bulk_rx_nak_timeout(musb, hw_ep);
+ return;
+ }
musb_ep_select(mbase, epnum);
- musb_writew(epio, MUSB_RXCSR,
- MUSB_RXCSR_H_WZC_BITS
- | MUSB_RXCSR_H_REQPKT);
+ rx_csr |= MUSB_RXCSR_H_WZC_BITS;
+ rx_csr &= ~MUSB_RXCSR_DATAERROR;
+ musb_writew(epio, MUSB_RXCSR, rx_csr);
goto finish;
} else {
head = &musb->in_bulk;
else
head = &musb->out_bulk;
+
+ /* Enable bulk RX 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)
+ qh->intv_reg =
+ (USB_SPEED_HIGH == qh->dev->speed) ? 8 : 4;
goto success;
} else if (best_end < 0) {
return -ENOSPC;
*
* The downside of disabling this is that transfer scheduling
* gets VERY unfair for nonperiodic transfers; a misbehaving
- * peripheral could make that hurt. Or for reads, one that's
- * perfectly normal: network and other drivers keep reads
- * posted at all times, having one pending for a week should
- * be perfectly safe.
+ * peripheral could make that hurt. That's perfectly normal
+ * for reads from network or serial adapters ... so we have
+ * partial NAKlimit support for bulk RX.
*
- * The upside of disabling it is avoidng transfer scheduling
- * code to put this aside for while.
+ * The upside of disabling it is simpler transfer scheduling.
*/
interval = 0;
}
projects / linux-2.6-omap-h63xx.git / commitdiff