Re: [RESEND PATCH 08/16] usb: musb: Fix receiving of bigger buffers

On Fri, 5 Feb 2021 20:12:04 +0100 Pali Rohár pali@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 lukma@denx.de

Signed-off-by: Pali Rohár pali@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

--

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