The USB function can respond to a Setup packet with ACK or, in case it's busy, it can ignore the Setup packet. The USB function usually gets busy if we hammer it with Control EP transfers too much (ie. sending multiple Get Descriptor requests in a single microframe tends to trigger it on certain USB sticks). The DWC2 controller will interpret not receiving an ACK after Setup packet as XACTERR. Check for this condition and if it happens, retry sending the Setup packet.
Signed-off-by: Marek Vasut marex@denx.de Cc: Chin Liang See clsee@altera.com Cc: Dinh Nguyen dinguyen@opensource.altera.com Cc: Hans de Goede hdegoede@redhat.com Cc: Stefan Roese sr@denx.de Cc: Stephen Warren swarren@nvidia.com --- drivers/usb/host/dwc2.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+)
diff --git a/drivers/usb/host/dwc2.c b/drivers/usb/host/dwc2.c index 30b51b3..8d3949e 100644 --- a/drivers/usb/host/dwc2.c +++ b/drivers/usb/host/dwc2.c @@ -737,6 +737,7 @@ int wait_for_chhltd(struct dwc2_hc_regs *hc_regs, uint32_t *sub, u8 *toggle) { int ret; uint32_t hcint, hctsiz; + u8 pid = *toggle;
ret = wait_for_bit(__func__, &hc_regs->hcint, DWC2_HCINT_CHHLTD, true, 1000, false); @@ -758,6 +759,19 @@ int wait_for_chhltd(struct dwc2_hc_regs *hc_regs, uint32_t *sub, u8 *toggle) if (hcint & (DWC2_HCINT_NAK | DWC2_HCINT_FRMOVRUN)) return -EAGAIN;
+ /* + * The USB function can respond to a Setup packet with ACK or, in + * case it's busy, it can ignore the Setup packet. The USB function + * usually gets busy if we hammer it with Control EP transfers too + * much (ie. sending multiple Get Descriptor requests in a single + * microframe tends to trigger it on certain USB sticks). The DWC2 + * controller will interpret not receiving an ACK after Setup packet + * as XACTERR. Check for this condition and if it happens, retry + * sending the Setup packet. + */ + if (hcint & DWC2_HCINT_XACTERR && (pid == DWC2_HC_PID_SETUP)) + return -EAGAIN; + debug("%s: Error (HCINT=%08x)\n", __func__, hcint); return -EINVAL; }