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Mon, 04 Nov 2024 16:43:25 +0000 (UTC) Received: from hardanger.blackshift.org (unknown [172.20.34.65]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by bjornoya.blackshift.org (Postfix) with ESMTPS id 834B7367DF1; Mon, 04 Nov 2024 16:43:23 +0000 (UTC) Received: from [172.20.34.65] (localhost [::1]) by hardanger.blackshift.org (OpenSMTPD) with ESMTP id e44711e1; Mon, 4 Nov 2024 16:43:22 +0000 (UTC) From: Marc Kleine-Budde Date: Mon, 04 Nov 2024 17:42:40 +0100 Subject: [PATCH can v3] can: mcp251xfd: mcp251xfd_get_tef_len(): fix length calculation Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20241104-mcp251xfd-fix-length-calculation-v3-1-608b6e7e2197@pengutronix.de> X-B4-Tracking: v=1; b=H4sIAH/5KGcC/42Nyw6DIBBFf8WwLg1Q8dFV/6PpgseoJBYNILEx/ nsnrpp04/LO3HvORiIEB5Hci40EyC66yWO4XQpiBuV7oM5iJoKJkjPG6dvMQvK1s7RzKx3B92m gRo1mGVXCMWWtrozhTIFmBDFzAGweiicxypMXHgcX0xQ+hzbz43XekDnlVLaNLivJGlvxx4ylJ YXJu/Vq4TBk8UMV8gRVIBWUtLquG91K9kfd9/0LHtUS8zABAAA= X-Change-ID: 20241001-mcp251xfd-fix-length-calculation-09b6cc10aeb0 To: Manivannan Sadhasivam , Thomas Kopp , Vincent Mailhol , Sven Schuchmann Cc: linux-can@vger.kernel.org, kernel@pengutronix.de, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Marc Kleine-Budde X-Mailer: b4 0.15-dev-dedf8 X-Developer-Signature: v=1; a=openpgp-sha256; l=2880; i=mkl@pengutronix.de; h=from:subject:message-id; bh=63xFusTRsY1L/nYoLVzTZYDCcu+dflkbrtHdaafc8Ow=; b=owEBbQGS/pANAwAKASg4oj56LbxvAcsmYgBnKPmFN0MvQy+Sg3vSdfw3tywkkT9FJrkcQEQqe gWP0ISUzWeJATMEAAEKAB0WIQRQQLqG4LYE3Sm8Pl8oOKI+ei28bwUCZyj5hQAKCRAoOKI+ei28 b/aTB/4tiMmTguV9zreuyT/rwm10dGSiYkqN2vMEjs770WOwPNxh+zX+pYyqt1llpm+U367uovF 59sgNZoY0x7CuT3xjrDOAuAyVB9ZsAf7rs+KgLPfu364rItSGUb+ByYWU3JwZKCfgc45MWtF6Xl b6o4+ZouLKt7QSRvwjL3N1OhZOxrbiGISx8sWgz6JYcCmIK6yxMr1bRU4kmP7Zw9vtxIw1kuj6k AVtwo9PjNtt66ZJcomC0rtRcLdMcQ7IPojctlSI9hyMHkt08agL/i9Zrvkfn7v4r8mM6aYLWNcG G2lQ7WeqcfzTeXaEFoRHJuJaxFTkLT1Im7GF9WKkkIexVrii X-Developer-Key: i=mkl@pengutronix.de; a=openpgp; fpr=C1400BA0B3989E6FBC7D5B5C2B5EE211C58AEA54 X-SA-Exim-Connect-IP: 2a0a:edc0:0:c01:1d::a2 X-SA-Exim-Mail-From: mkl@pengutronix.de X-SA-Exim-Scanned: No (on metis.whiteo.stw.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Commit b8e0ddd36ce9 ("can: mcp251xfd: tef: prepare to workaround broken TEF FIFO tail index erratum") introduced mcp251xfd_get_tef_len() to get the number of unhandled transmit events from the Transmit Event FIFO (TEF). As the TEF has no head pointer, the driver uses the TX FIFO's tail pointer instead, assuming that send frames are completed. However the check for the TEF being full was not correct. This leads to the driver stop working if the TEF is full. Fix the TEF full check by assuming that if, from the driver's point of view, there are no free TX buffers in the chip and the TX FIFO is empty, all messages must have been sent and the TEF must therefore be full. Reported-by: Sven Schuchmann Closes: https://patch.msgid.link/FR3P281MB155216711EFF900AD9791B7ED9692@FR3= P281MB1552.DEUP281.PROD.OUTLOOK.COM Fixes: b8e0ddd36ce9 ("can: mcp251xfd: tef: prepare to workaround broken TEF= FIFO tail index erratum") Tested-by: Sven Schuchmann Cc: stable@vger.kernel.org Signed-off-by: Marc Kleine-Budde Reviewed-by: Simon Horman --- Changes in v3: - add proper patch description - added Sven's Tested-by - Link to v2: https://patch.msgid.link/20241025-mcp251xfd-fix-length-calcul= ation-v2-1-ea5db778b950@pengutronix.de 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-calcu= lation-v1-1-598b46508d61@pengutronix.de --- 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/ca= n/spi/mcp251xfd/mcp251xfd-tef.c index f732556d233a7be3b43f6f08e0b8f25732190104..d3ac865933fdf6c4ecdd80ad4d7= accbff51eb0f8 100644 --- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-tef.c +++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-tef.c @@ -16,9 +16,9 @@ =20 #include "mcp251xfd.h" =20 -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; } =20 static inline int @@ -122,7 +122,11 @@ mcp251xfd_get_tef_len(struct mcp251xfd_priv *priv, u8 = *len_p) if (err) return err; =20 - 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) =3D=3D 0) { *len_p =3D tx_ring->obj_num; return 0; } --- base-commit: 5ccdcdf186aec6b9111845fd37e1757e9b413e2f change-id: 20241001-mcp251xfd-fix-length-calculation-09b6cc10aeb0 Best regards, --=20 Marc Kleine-Budde