From patchwork Mon Jun 24 14:45:13 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Marc Kleine-Budde X-Patchwork-Id: 13709616 X-Patchwork-Delegate: kuba@kernel.org Received: from metis.whiteo.stw.pengutronix.de (metis.whiteo.stw.pengutronix.de [185.203.201.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B0D8A19DF7B for ; Mon, 24 Jun 2024 14:45:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.203.201.7 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719240352; cv=none; b=VJVeSf4G6CYyUMldbyNuBdthmqc2HXR4mC5GW5iKiffZrVL+00uRyUg9TvStEGIUt7/ySD+E8akRI5Zumyhwc/5+b40a6OaL4kyXBz5CX6+xmHjmXVzaqULgoW1AI4pdKZGkz+xJeNeZu71kVnpoGyHuWzSEZtpn5rXPwnVSHWo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719240352; c=relaxed/simple; bh=xLCNUDu40aLCYUBXXMUH9tJ5hNEyfwbDsv7k7YO+29E=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=qextbsjvtolLp8olGYR7I3kYgw3w6ssasii79vJowxKZLffPybvjZPZxKOF1TMxNNC5Ak0FbmDD2TvKnyLKArr/DTLhWPT6HyRXJJnBdMJRvK16acZApHUsT+dDR0DtpxS6GKKo9+R5ffi5zrrCDhMzW3J38cwr0O0BSfkVS2rE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de; spf=pass smtp.mailfrom=pengutronix.de; arc=none smtp.client-ip=185.203.201.7 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=pengutronix.de Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1sLkx1-00030X-RJ for netdev@vger.kernel.org; Mon, 24 Jun 2024 16:45:47 +0200 Received: from [2a0a:edc0:0:b01:1d::7b] (helo=bjornoya.blackshift.org) by drehscheibe.grey.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1sLkwy-004fqk-Th for netdev@vger.kernel.org; Mon, 24 Jun 2024 16:45:44 +0200 Received: from dspam.blackshift.org (localhost [127.0.0.1]) by bjornoya.blackshift.org (Postfix) with SMTP id 8DFDE2F1A8F for ; Mon, 24 Jun 2024 14:45:44 +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 7F4792F1A12; Mon, 24 Jun 2024 14:45:38 +0000 (UTC) Received: from [192.168.178.131] (localhost [::1]) by hardanger.blackshift.org (OpenSMTPD) with ESMTP id f1d79382; Mon, 24 Jun 2024 14:45:37 +0000 (UTC) From: Marc Kleine-Budde Date: Mon, 24 Jun 2024 16:45:13 +0200 Subject: [PATCH v3 9/9] can: mcp251xfd: tef: update workaround for erratum DS80000789E 6 of mcp2518fd Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20240624-mcp251xfd-workaround-erratum-6-v3-9-caf7e5f27f60@pengutronix.de> References: <20240624-mcp251xfd-workaround-erratum-6-v3-0-caf7e5f27f60@pengutronix.de> In-Reply-To: <20240624-mcp251xfd-workaround-erratum-6-v3-0-caf7e5f27f60@pengutronix.de> To: Manivannan Sadhasivam , Vincent Mailhol , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni Cc: Manivannan Sadhasivam , Thomas Kopp , =?utf-8?q?Stefan_Alth=C3=B6fer?= , kernel@pengutronix.de, linux-can@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Marc Kleine-Budde X-Mailer: b4 0.15-dev-13183 X-Developer-Signature: v=1; a=openpgp-sha256; l=5274; i=mkl@pengutronix.de; h=from:subject:message-id; bh=xLCNUDu40aLCYUBXXMUH9tJ5hNEyfwbDsv7k7YO+29E=; b=owEBbQGS/pANAwAKASg4oj56LbxvAcsmYgBmeYaP3y5supn8zqp69efl0JrQmRQk/Fmc5LnL6 N9UB9KAr3iJATMEAAEKAB0WIQRQQLqG4LYE3Sm8Pl8oOKI+ei28bwUCZnmGjwAKCRAoOKI+ei28 b6xiB/wIYEL3bAcqMfubvzhFoJXKC6fsS4Phf2P1rVa7FaW/ETUdZ4xHk2llJet1UBnEFeweFGv Zt+4kJMTGspntzHnKPoeDwXJ1raqhRGNnKkdXVaWBPAmfY9MM+1rNsS8pw39qTVfAAmiGxNSDRU vq/qP6zQtGjzjci7asncxjdzsr19YTLWYSA1H8GGY5rKEzh6j0S7b9wX8XQWXxriQlThYyubEAL fbqRJD97LaaLymYvZN5h8PYZzXL29N8lZjN03svJjXUYkyV8Nu1km93fVM+aRV90fme6xuhZNoY JgJJD3t7ZF/eFWpTwcMUr005JiZrNCFXHAZrtDpqvWs8Tnzs 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: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org This patch updates the workaround for a problem similar to erratum DS80000789E 6 of the mcp2518fd, the other variants of the chip family (mcp2517fd and mcp251863) are probably also affected. Erratum DS80000789E 6 says "reading of the FIFOCI bits in the FIFOSTA register for an RX FIFO may be corrupted". However observation shows that this problem is not limited to RX FIFOs but also effects the TEF FIFO. In the bad case, the driver reads a too large head index. As the FIFO is implemented as a ring buffer, this results in re-handling old CAN transmit complete events. Every transmit complete event contains with a sequence number that equals to the sequence number of the corresponding TX request. This way old TX complete events can be detected. If the original driver detects a non matching sequence number, it prints an info message and tries again later. As wrong sequence numbers can be explained by the erratum DS80000789E 6, demote the info message to debug level, streamline the code and update the comments. Keep the behavior: If an old CAN TX complete event is detected, abort the iteration and mark the number of valid CAN TX complete events as processed in the chip by incrementing the FIFO's tail index. Cc: Stefan Althöfer Cc: Thomas Kopp Signed-off-by: Marc Kleine-Budde --- drivers/net/can/spi/mcp251xfd/mcp251xfd-tef.c | 71 ++++++++++----------------- 1 file changed, 27 insertions(+), 44 deletions(-) diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-tef.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-tef.c index f5f05e7baef2..2c92e127cef8 100644 --- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-tef.c +++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-tef.c @@ -60,56 +60,39 @@ static int mcp251xfd_check_tef_tail(const struct mcp251xfd_priv *priv) return 0; } -static int -mcp251xfd_handle_tefif_recover(const struct mcp251xfd_priv *priv, const u32 seq) -{ - const struct mcp251xfd_tx_ring *tx_ring = priv->tx; - u32 tef_sta; - int err; - - err = regmap_read(priv->map_reg, MCP251XFD_REG_TEFSTA, &tef_sta); - if (err) - return err; - - if (tef_sta & MCP251XFD_REG_TEFSTA_TEFOVIF) { - netdev_err(priv->ndev, - "Transmit Event FIFO buffer overflow.\n"); - return -ENOBUFS; - } - - netdev_info(priv->ndev, - "Transmit Event FIFO buffer %s. (seq=0x%08x, tef_tail=0x%08x, tef_head=0x%08x, tx_head=0x%08x).\n", - tef_sta & MCP251XFD_REG_TEFSTA_TEFFIF ? - "full" : tef_sta & MCP251XFD_REG_TEFSTA_TEFNEIF ? - "not empty" : "empty", - seq, priv->tef->tail, priv->tef->head, tx_ring->head); - - /* The Sequence Number in the TEF doesn't match our tef_tail. */ - return -EAGAIN; -} - static int mcp251xfd_handle_tefif_one(struct mcp251xfd_priv *priv, const struct mcp251xfd_hw_tef_obj *hw_tef_obj, unsigned int *frame_len_ptr) { struct net_device_stats *stats = &priv->ndev->stats; + u32 seq, tef_tail_masked, tef_tail; struct sk_buff *skb; - u32 seq, seq_masked, tef_tail_masked, tef_tail; - seq = FIELD_GET(MCP251XFD_OBJ_FLAGS_SEQ_MCP2518FD_MASK, + /* Use the MCP2517FD mask on the MCP2518FD, too. We only + * compare 7 bits, this is enough to detect old TEF objects. + */ + seq = FIELD_GET(MCP251XFD_OBJ_FLAGS_SEQ_MCP2517FD_MASK, hw_tef_obj->flags); - - /* Use the MCP2517FD mask on the MCP2518FD, too. We only - * compare 7 bits, this should be enough to detect - * net-yet-completed, i.e. old TEF objects. - */ - seq_masked = seq & - field_mask(MCP251XFD_OBJ_FLAGS_SEQ_MCP2517FD_MASK); tef_tail_masked = priv->tef->tail & field_mask(MCP251XFD_OBJ_FLAGS_SEQ_MCP2517FD_MASK); - if (seq_masked != tef_tail_masked) - return mcp251xfd_handle_tefif_recover(priv, seq); + + /* According to mcp2518fd erratum DS80000789E 6. the FIFOCI + * bits of a FIFOSTA register, here the TX FIFO tail index + * might be corrupted and we might process past the TEF FIFO's + * head into old CAN frames. + * + * Compare the sequence number of the currently processed CAN + * frame with the expected sequence number. Abort with + * -EBADMSG if an old CAN frame is detected. + */ + if (seq != tef_tail_masked) { + netdev_dbg(priv->ndev, "%s: chip=0x%02x ring=0x%02x\n", __func__, + seq, tef_tail_masked); + stats->tx_fifo_errors++; + + return -EBADMSG; + } tef_tail = mcp251xfd_get_tef_tail(priv); skb = priv->can.echo_skb[tef_tail]; @@ -219,12 +202,12 @@ int mcp251xfd_handle_tefif(struct mcp251xfd_priv *priv) unsigned int frame_len = 0; err = mcp251xfd_handle_tefif_one(priv, &hw_tef_obj[i], &frame_len); - /* -EAGAIN means the Sequence Number in the TEF - * doesn't match our tef_tail. This can happen if we - * read the TEF objects too early. Leave loop let the - * interrupt handler call us again. + /* -EBADMSG means we're affected by mcp2518fd erratum + * DS80000789E 6., i.e. the Sequence Number in the TEF + * doesn't match our tef_tail. Don't process any + * further and mark processed frames as good. */ - if (err == -EAGAIN) + if (err == -EBADMSG) goto out_netif_wake_queue; if (err) return err;