From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E8CB2C6FA90 for ; Wed, 28 Sep 2022 09:06:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231587AbiI1JGn (ORCPT ); Wed, 28 Sep 2022 05:06:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36532 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233333AbiI1JGg (ORCPT ); Wed, 28 Sep 2022 05:06:36 -0400 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 148BF140C2 for ; Wed, 28 Sep 2022 02:06:35 -0700 (PDT) Received: from gallifrey.ext.pengutronix.de ([2001:67c:670:201:5054:ff:fe8d:eefb] helo=bjornoya.blackshift.org) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1odT1V-00075H-Fx for netdev@vger.kernel.org; Wed, 28 Sep 2022 11:06:33 +0200 Received: from dspam.blackshift.org (localhost [127.0.0.1]) by bjornoya.blackshift.org (Postfix) with SMTP id CC2C0EF6A4 for ; Wed, 28 Sep 2022 09:06:32 +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 D0E1DEF698; Wed, 28 Sep 2022 09:06:30 +0000 (UTC) Received: from blackshift.org (localhost [::1]) by hardanger.blackshift.org (OpenSMTPD) with ESMTP id 1931824f; Wed, 28 Sep 2022 09:06:29 +0000 (UTC) From: Marc Kleine-Budde To: netdev@vger.kernel.org Cc: davem@davemloft.net, kuba@kernel.org, linux-can@vger.kernel.org, kernel@pengutronix.de, Marc Kleine-Budde , Jacob Kroon , stable@vger.kernel.org Subject: [PATCH net] can: c_can: don't cache TX messages for C_CAN cores Date: Wed, 28 Sep 2022 11:06:29 +0200 Message-Id: <20220928090629.1124190-2-mkl@pengutronix.de> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220928090629.1124190-1-mkl@pengutronix.de> References: <20220928090629.1124190-1-mkl@pengutronix.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 2001:67c:670:201:5054:ff:fe8d:eefb X-SA-Exim-Mail-From: mkl@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: netdev@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org As Jacob noticed, the optimization introduced in 387da6bc7a82 ("can: c_can: cache frames to operate as a true FIFO") doesn't properly work on C_CAN, but on D_CAN IP cores. The exact reasons are still unknown. For now disable caching if CAN frames in the TX path for C_CAN cores. Fixes: 387da6bc7a82 ("can: c_can: cache frames to operate as a true FIFO") Link: https://lore.kernel.org/all/20220928083354.1062321-1-mkl@pengutronix.de Link: https://lore.kernel.org/all/15a8084b-9617-2da1-6704-d7e39d60643b@gmail.com Reported-by: Jacob Kroon Tested-by: Jacob Kroon Cc: stable@vger.kernel.org # v5.15 Signed-off-by: Marc Kleine-Budde --- drivers/net/can/c_can/c_can.h | 17 +++++++++++++++-- drivers/net/can/c_can/c_can_main.c | 11 +++++------ 2 files changed, 20 insertions(+), 8 deletions(-) diff --git a/drivers/net/can/c_can/c_can.h b/drivers/net/can/c_can/c_can.h index f23a03300a81..029cd8194ed5 100644 --- a/drivers/net/can/c_can/c_can.h +++ b/drivers/net/can/c_can/c_can.h @@ -235,9 +235,22 @@ static inline u8 c_can_get_tx_tail(const struct c_can_tx_ring *ring) return ring->tail & (ring->obj_num - 1); } -static inline u8 c_can_get_tx_free(const struct c_can_tx_ring *ring) +static inline u8 c_can_get_tx_free(const struct c_can_priv *priv, + const struct c_can_tx_ring *ring) { - return ring->obj_num - (ring->head - ring->tail); + u8 head = c_can_get_tx_head(ring); + u8 tail = c_can_get_tx_tail(ring); + + if (priv->type == BOSCH_D_CAN) + return ring->obj_num - (ring->head - ring->tail); + + /* This is not a FIFO. C/D_CAN sends out the buffers + * prioritized. The lowest buffer number wins. + */ + if (head < tail) + return 0; + + return ring->obj_num - head; } #endif /* C_CAN_H */ diff --git a/drivers/net/can/c_can/c_can_main.c b/drivers/net/can/c_can/c_can_main.c index dc8132862f33..d6605dbb7737 100644 --- a/drivers/net/can/c_can/c_can_main.c +++ b/drivers/net/can/c_can/c_can_main.c @@ -429,7 +429,7 @@ static void c_can_setup_receive_object(struct net_device *dev, int iface, static bool c_can_tx_busy(const struct c_can_priv *priv, const struct c_can_tx_ring *tx_ring) { - if (c_can_get_tx_free(tx_ring) > 0) + if (c_can_get_tx_free(priv, tx_ring) > 0) return false; netif_stop_queue(priv->dev); @@ -437,7 +437,7 @@ static bool c_can_tx_busy(const struct c_can_priv *priv, /* Memory barrier before checking tx_free (head and tail) */ smp_mb(); - if (c_can_get_tx_free(tx_ring) == 0) { + if (c_can_get_tx_free(priv, tx_ring) == 0) { netdev_dbg(priv->dev, "Stopping tx-queue (tx_head=0x%08x, tx_tail=0x%08x, len=%d).\n", tx_ring->head, tx_ring->tail, @@ -465,7 +465,7 @@ static netdev_tx_t c_can_start_xmit(struct sk_buff *skb, idx = c_can_get_tx_head(tx_ring); tx_ring->head++; - if (c_can_get_tx_free(tx_ring) == 0) + if (c_can_get_tx_free(priv, tx_ring) == 0) netif_stop_queue(dev); if (idx < c_can_get_tx_tail(tx_ring)) @@ -748,7 +748,7 @@ static void c_can_do_tx(struct net_device *dev) return; tx_ring->tail += pkts; - if (c_can_get_tx_free(tx_ring)) { + if (c_can_get_tx_free(priv, tx_ring)) { /* Make sure that anybody stopping the queue after * this sees the new tx_ring->tail. */ @@ -760,8 +760,7 @@ static void c_can_do_tx(struct net_device *dev) stats->tx_packets += pkts; tail = c_can_get_tx_tail(tx_ring); - - if (tail == 0) { + if (priv->type == BOSCH_D_CAN && tail == 0) { u8 head = c_can_get_tx_head(tx_ring); /* Start transmission for all cached messages */ base-commit: 44d70bb561dac9363f45787aa93dfca36877ee01 -- 2.35.1