[PATCH] usb: dwc2: hcd: fix periodic transfer schedule sequence

From: Yunzhi Li
Date: Mon Nov 16 2015 - 10:26:32 EST


When checking dwc2 host channel interrupts, handle qh in
periodic_sched_queued list at first, then we could make sure CSPLIT
packets scheduled in the same order as SSPLIT packets.

Signed-off-by: Yunzhi Li <lyz@xxxxxxxxxxxxxx>
---
drivers/usb/dwc2/hcd_intr.c | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)

diff --git a/drivers/usb/dwc2/hcd_intr.c b/drivers/usb/dwc2/hcd_intr.c
index bda0b21..e8e8970 100644
--- a/drivers/usb/dwc2/hcd_intr.c
+++ b/drivers/usb/dwc2/hcd_intr.c
@@ -2115,6 +2115,8 @@ static void dwc2_hc_intr(struct dwc2_hsotg *hsotg)
{
u32 haint;
int i;
+ int hc_num;
+ struct dwc2_qh *qh, *qh_tmp;

haint = dwc2_readl(hsotg->regs + HAINT);
if (dbg_perio()) {
@@ -2123,6 +2125,26 @@ static void dwc2_hc_intr(struct dwc2_hsotg *hsotg)
dev_vdbg(hsotg->dev, "HAINT=%08x\n", haint);
}

+ /*
+ * According to USB 2.0 spec section 11.18.8, a host must
+ * issue complete-split transactions in a microframe for a
+ * set of full-/low-speed endpoints in the same relative
+ * order as the start-splits were issued in a microframe for.
+ * So here we should at first picking up host channels
+ * from periodic_sched_queued list and checking if there is
+ * any start-split have already finished then schedule
+ * complete-split in the same order.
+ */
+ list_for_each_entry_safe(qh, qh_tmp,
+ &hsotg->periodic_sched_queued,
+ qh_list_entry) {
+ hc_num = qh->channel->hc_num;
+ if (haint & (1 << hc_num)) {
+ dwc2_hc_n_intr(hsotg, hc_num);
+ haint &= ~(1 << hc_num);
+ }
+ }
+
for (i = 0; i < hsotg->core_params->host_channels; i++) {
if (haint & (1 << i))
dwc2_hc_n_intr(hsotg, i);
--
1.9.1


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