diff options
| -rw-r--r-- | drivers/usb/musb/musb_host.c | 22 |
1 files changed, 16 insertions, 6 deletions
diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c index 26c65e66cc0f..795a45b1b25b 100644 --- a/drivers/usb/musb/musb_host.c +++ b/drivers/usb/musb/musb_host.c @@ -112,22 +112,32 @@ static void musb_h_tx_flush_fifo(struct musb_hw_ep *ep) struct musb *musb = ep->musb; void __iomem *epio = ep->regs; u16 csr; - u16 lastcsr = 0; int retries = 1000; csr = musb_readw(epio, MUSB_TXCSR); while (csr & MUSB_TXCSR_FIFONOTEMPTY) { - if (csr != lastcsr) - dev_dbg(musb->controller, "Host TX FIFONOTEMPTY csr: %02x\n", csr); - lastcsr = csr; csr |= MUSB_TXCSR_FLUSHFIFO | MUSB_TXCSR_TXPKTRDY; musb_writew(epio, MUSB_TXCSR, csr); csr = musb_readw(epio, MUSB_TXCSR); - if (WARN(retries-- < 1, + + /* + * FIXME: sometimes the tx fifo flush failed, it has been + * observed during device disconnect on AM335x. + * + * To reproduce the issue, ensure tx urb(s) are queued when + * unplug the usb device which is connected to AM335x usb + * host port. + * + * I found using a usb-ethernet device and running iperf + * (client on AM335x) has very high chance to trigger it. + * + * Better to turn on dev_dbg() in musb_cleanup_urb() with + * CPPI enabled to see the issue when aborting the tx channel. + */ + if (dev_WARN_ONCE(musb->controller, retries-- < 1, "Could not flush host TX%d fifo: csr: %04x\n", ep->epnum, csr)) return; - mdelay(1); } } |
