usb: musb: clear RXCSR_AUTOCLEAR before PIO read
If RXCSR_AUTOCLEAR flag is not cleard before PIO reading, one packet may be recieved by musb fifo, but no chance to notify software, so cause packet loss, follows the detailed process: - PIO read one packet - musb fifo auto clear the MUSB_RXCSR_RXPKTRDY - musb continue to recieve the next packet, and MUSB_RXCSR_RXPKTRDY is set - software clear the MUSB_RXCSR_RXPKTRDY, so there is no chance for musb to notify software that the 2nd recieved packet. The patch does fix the g_ether issue below: - use fifo_mode 3 to enable double buffer - 'ping -s 1024 IP_OF_BEAGLE_XM' - one usb packet of 512 byte is lost, so ping failed, which can be observed by wireshark note: Beagle xm takes musb rtl1.8 and may fallback to pio mode for unaligned buffer. Signed-off-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Felipe Balbi <balbi@ti.com>
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