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 9FC18C433FE for ; Mon, 3 Oct 2022 07:13:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229835AbiJCHM7 (ORCPT ); Mon, 3 Oct 2022 03:12:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47214 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229821AbiJCHMc (ORCPT ); Mon, 3 Oct 2022 03:12:32 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7FAE23ECFC; Mon, 3 Oct 2022 00:12:26 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 9CF3960F9B; Mon, 3 Oct 2022 07:12:25 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B50E8C433C1; Mon, 3 Oct 2022 07:12:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1664781145; bh=Q9tUnQkxGVZdqQdRAIeF9tYNgjJi/waFbFNnzAxQM14=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2BpIEcgFVCadC9p1JaaBwkY0LDc7cqN1vNcRUYr+s7+NJSokN9zXAqdruLV23GyKN xK1HJdizT4jpwhyG5FxAdaEbmr1VTKgkIsWhPgI90mHm5QQWPgMI+NO0pObPtJvCul o8YD8qR3HEDIKWdeC0xKXiLwbPJ8ESrBACArV+KM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jacob Kroon , Marc Kleine-Budde Subject: [PATCH 5.19 014/101] can: c_can: dont cache TX messages for C_CAN cores Date: Mon, 3 Oct 2022 09:10:10 +0200 Message-Id: <20221003070724.856221977@linuxfoundation.org> X-Mailer: git-send-email 2.37.3 In-Reply-To: <20221003070724.490989164@linuxfoundation.org> References: <20221003070724.490989164@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Marc Kleine-Budde commit 81d192c2ce74157e717e1fc4b68791f82f7499d4 upstream. 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 Signed-off-by: Greg Kroah-Hartman --- 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(-) --- 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 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 */ --- 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(s 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 /* 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(stru 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_devic 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_devic 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 */