On Fri, 5 Feb 2021 20:12:04 +0100 Pali Rohár <p...@kernel.org> wrote:
> If musb_peri_rx_ep() was called to processed received HW buffer but
> U-Boot cannot read it yet (e.g. because U-Boot SW buffer is full)
> then interrupt was marked as processed but HW buffer stayed
> unprocessed.
>
> U-Boot tried to process this buffer again when it receive interrupt
> again, but it can receive it only when sender (host) send a new data.
> As sender (host) is not going to send a new data until U-Boot process
> current data this issue caused a deadlock in case sender (host) is
> emitting data faster than U-Boot can process it.
>
> Reading musb intrrx register automatically clears this register and
> mark interrupt as processed. So to prevent marking interrupt in
> U-Boot as processed and a new variable pending_intrrx which would
> contain unprocessed bits of intrrx register.
>
> And as a second step, every time when musb_peri_rx_ep() is called and
> there are waiting data to be processed (signaled by
> MUSB_RXCSR_RXPKTRDY) either acknowledge sender (via
> musb_peri_rx_ack()) that whole HW buffer was processed or set
> corresponding bit in pending_intrrx that HW buffer was not fully
> processed yet and next iteration is required after U-Boot allocate
> space for reading HW buffer.
>
> This patch fixes receiving large usb buffers, e.g. file transfer via
> Kermit protocol implemented by 'loadb' U-Boot command over usbtty
> serial console.
Reviewed-by: Lukasz Majewski <lu...@denx.de>
>
> Signed-off-by: Pali Rohár <p...@kernel.org>
> ---
> drivers/usb/musb/musb_udc.c | 16 +++++++++++++++-
> 1 file changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/musb/musb_udc.c b/drivers/usb/musb/musb_udc.c
> index 28719cc3f6..7c74422623 100644
> --- a/drivers/usb/musb/musb_udc.c
> +++ b/drivers/usb/musb/musb_udc.c
> @@ -104,6 +104,8 @@ struct usb_endpoint_instance *ep0_endpoint;
> static struct usb_device_instance *udc_device;
> static int enabled;
>
> +u16 pending_intrrx;
> +
> #ifdef MUSB_DEBUG
> static void musb_db_regs(void)
> {
> @@ -664,7 +666,10 @@ static void musb_peri_rx_ep(unsigned int ep)
> /* The common musb fifo reader */
> read_fifo(ep, length, data);
>
> - musb_peri_rx_ack(ep);
> + if (length == peri_rxcount)
> + musb_peri_rx_ack(ep);
> + else
> + pending_intrrx |= (1 << ep);
>
> /*
> * urb's actual_length is updated in
> @@ -677,18 +682,24 @@ static void musb_peri_rx_ep(unsigned int ep)
> serial_printf("ERROR : %s %d
> no space " "in rcv buffer\n",
> __PRETTY_FUNCTION__,
> ep); +
> + pending_intrrx |= (1 << ep);
> }
> } else {
> if (debug_level > 0)
> serial_printf("ERROR : %s %d problem
> with " "endpoint\n",
> __PRETTY_FUNCTION__,
> ep); +
> + pending_intrrx |= (1 << ep);
> }
>
> } else {
> if (debug_level > 0)
> serial_printf("ERROR : %s %d with nothing to
> do\n", __PRETTY_FUNCTION__, ep);
> +
> + musb_peri_rx_ack(ep);
> }
> }
>
> @@ -770,6 +781,9 @@ void udc_irq(void)
> intrrx = readw(&musbr->intrrx);
> intrtx = readw(&musbr->intrtx);
>
> + intrrx |= pending_intrrx;
> + pending_intrrx = 0;
> +
> if (intrrx)
> musb_peri_rx(intrrx);
>
Best regards,
Lukasz Majewski
--
DENX Software Engineering GmbH, Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lu...@denx.de
pgpaD_rshHxnV.pgp
Description: OpenPGP digital signature
