Commit 2fbb397f authored Jan 05, 2021 by Marc Kleine-Budde

can: mcp251xfd: mcp251xfd_handle_rxif_ring(): first increment RX tail pointer in HW, then in driver

The previous patch fixes a TEF vs. TX race condition, by first updating the TEF
tail pointer in hardware, and then updating the driver internal pointer.

The same pattern exists in the RX-path, too. This should be no problem, as the
driver accesses the RX-FIFO from the interrupt handler only, thus the access is
properly serialized. Fix the order here, too, so that the TEF- and RX-path look
similar.

Fixes: 1f652bb6 ("can: mcp25xxfd: rx-path: reduce number of SPI core requests to set UINC bit")
Link: https://lore.kernel.org/r/20210105214138.3150886-3-mkl@pengutronix.de

Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

parent 6086f02a

drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c

+4 −4

Original line number	Diff line number	Diff line
		@@ -1552,10 +1552,8 @@ mcp251xfd_handle_rxif_ring(struct mcp251xfd_priv *priv,

		/* Increment the RX FIFO tail pointer 'len' times in a
		* single SPI message.
		*/
		ring->tail += len;

		/* Note:
		*
		* Note:
		*
		* "cs_change == 1" on the last transfer results in an
		* active chip select after the complete SPI
		@@ -1571,6 +1569,8 @@ mcp251xfd_handle_rxif_ring(struct mcp251xfd_priv *priv,
		last_xfer->cs_change = 1;
		if (err)
		return err;

		ring->tail += len;
		}

		return 0;