On 11/05/2015 12:25 PM, Felipe Balbi wrote:
Hi, Bin Liu <b-liu@xxxxxx> writes:Here are a few changes in musb_h_tx_flush_fifo(). - Refering to 2ccc6d30a (usb: musb: fix bit mask for CSR in musb_h_tx_flush_fifo()), the datasheet says that MUSB_TXCSR_FLUSHFIFO is only valid when MUSB_TXCSR_TXPKTRDY is set as well. It means MUSB_TXCSR_TXPKTRDY should be checked, not set. - It seems to be common that sometimes (if not always) musb is unable to flush tx fifo during urb dequeue. But it seems to be harmless, since the tx fifo flush is done again in musb_ep_program() when re-use the hw_ep. But the WARN() scares many end users, so change it to dev_dbg(). - applications could queue up many tx urbs, then the 1ms delay could causes minutes of delay in device disconnect. So remove it to get better user experience. The 1ms delay does not help the flushing anyway. - cleanup the debug code - related to lastcsr. Signed-off-by: Bin Liu <b-liu@xxxxxx> --- drivers/usb/musb/musb_host.c | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-) diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c index 883a9ad..f9d4b4f 100644 --- a/drivers/usb/musb/musb_host.c +++ b/drivers/usb/musb/musb_host.c @@ -112,22 +112,18 @@ 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; + while (csr & (MUSB_TXCSR_FIFONOTEMPTY | MUSB_TXCSR_TXPKTRDY)) {this doesn't really fix the problem. This check will be true if either or both bits are set. You want only when both are set, so it should be: while ((csr & FIFONOTEMPTY) && (csr & TXPKTRDY))
Ahh, I should have used (csr & (MUSB_TXCSR_FIFONOTEMPTY | MUSB_TXCSR_TXPKTRDY) == MUSB_TXCSR_FIFONOTEMPTY | MUSB_TXCSR_TXPKTRDY), but it is too long. V2 comes soon.
Thanks, -Bin. -- 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
