Reported-by: Sven Schuchmann <schuchmann@xxxxxxxxxxxxxxxxx> Closes: https://patch.msgid.link/FR3P281MB155216711EFF900AD9791B7ED9692@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Fixes: b8e0ddd36ce9 ("can: mcp251xfd: tef: prepare to workaround broken TEF FIFO tail index erratum") Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> --- Hello, I got the empty check wrong and fixed it. Please test. Marc --- Changes in v2: - mcp251xfd_tx_fifo_sta_empty(): fix check if TX-FIFO is empty - Link to RFC: https://patch.msgid.link/20241001-mcp251xfd-fix-length-calculation-v1-1-598b46508d61@xxxxxxxxxxxxxx --- drivers/net/can/spi/mcp251xfd/mcp251xfd-tef.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-tef.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-tef.c index f732556d233a7be3b43f6f08e0b8f25732190104..d3ac865933fdf6c4ecdd80ad4d7accbff51eb0f8 100644 --- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-tef.c +++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-tef.c @@ -16,9 +16,9 @@ #include "mcp251xfd.h" -static inline bool mcp251xfd_tx_fifo_sta_full(u32 fifo_sta) +static inline bool mcp251xfd_tx_fifo_sta_empty(u32 fifo_sta) { - return !(fifo_sta & MCP251XFD_REG_FIFOSTA_TFNRFNIF); + return fifo_sta & MCP251XFD_REG_FIFOSTA_TFERFFIF; } static inline int @@ -122,7 +122,11 @@ mcp251xfd_get_tef_len(struct mcp251xfd_priv *priv, u8 *len_p) if (err) return err; - if (mcp251xfd_tx_fifo_sta_full(fifo_sta)) { + /* If the chip says the TX-FIFO is empty, but there are no TX + * buffers free in the ring, we assume all have been sent. + */ + if (mcp251xfd_tx_fifo_sta_empty(fifo_sta) && + mcp251xfd_get_tx_free(tx_ring) == 0) { *len_p = tx_ring->obj_num; return 0; } --- base-commit: 9efc44fb2dba6138b0575826319200049078679a change-id: 20241001-mcp251xfd-fix-length-calculation-09b6cc10aeb0 Best regards, -- Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>