In peripherals, m_can_rx_handler is called with quota = 1 from an ISR
context. If the M_CAN reports a high volume of errors, such as message
loss due to heavy bus traffic, then error handling, which is prioritised
in m_can_rx_handler, fills the quota immediately, and RX does not occur.
This has been observed to cause an indefinite blocking of RX.
The patch fixes this by ensuring that in peripherals, m_can_do_rx_poll
is always called with a quota of at least 1, regardless of any errors
handled.
This has been tested with the TCAN4550 under heavy bus traffic; message
loss is still detected correctly.
Signed-off-by: Torin Cooper-Bennun <torin@xxxxxxxxxxxxxxxxxx>
---
drivers/net/can/m_can/m_can.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index 3752520a7d4b..3ec42e613ca1 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -866,8 +866,14 @@ static int m_can_rx_handler(struct net_device *dev, int quota)
if (irqstatus & IR_ERR_BUS_30X)
work_done += m_can_handle_bus_errors(dev, irqstatus, psr);
- if (irqstatus & IR_RF0N)
- work_done += m_can_do_rx_poll(dev, (quota - work_done));
+ if (irqstatus & IR_RF0N) {
+ int rx_quota = quota - work_done;
+
+ if (cdev->is_peripheral && (rx_quota <= 0))
+ rx_quota = 1;
+
+ work_done += m_can_do_rx_poll(dev, rx_quota);
+ }
end:
return work_done;
}
--
2.30.1
