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 91E06C43217 for ; Wed, 16 Nov 2022 20:54:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234491AbiKPUyJ (ORCPT ); Wed, 16 Nov 2022 15:54:09 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36328 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238629AbiKPUxr (ORCPT ); Wed, 16 Nov 2022 15:53:47 -0500 Received: from mail-ej1-x62e.google.com (mail-ej1-x62e.google.com [IPv6:2a00:1450:4864:20::62e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 443CBE3E for ; Wed, 16 Nov 2022 12:53:27 -0800 (PST) Received: by mail-ej1-x62e.google.com with SMTP id gv23so14439503ejb.3 for ; Wed, 16 Nov 2022 12:53:27 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=baylibre-com.20210112.gappssmtp.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=ymKWfG3hBUHC+wOiiQxZhyFHyJiOcWTWeXnW4/XpvSQ=; b=uBIdtaeGMMK0etaJ10sYW6BxgNAyYojLXCGy0W42C+OfWLPOupay7/r0gtDdbrusfx UMGtFFUhGTNuo62g/z04us3xcWWsJylHgFAzaLUOKDz4nkF7I6lR5JYF1XR+1z9PCcMO SWZ5+W2N46uWnqy/y4Iec02er6vZlbge75TGJyzfM44ovW2lte7VHobLp4A7N+P1kHiE hSV2cRdrnkUqf3fhiHpB7Ya2OHa2borOYj/kxMXgVL392o4f21DoNWSwft4nNhJSLfM6 O54h8A2SVNF+4tTC6/YQnzgL/WfzCj9ZIJUkJ3wnyAi1hCo1xrSRnjhVaINTIrKp94SE Jm3g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=ymKWfG3hBUHC+wOiiQxZhyFHyJiOcWTWeXnW4/XpvSQ=; b=40tMeP+1VFAejYu2iaN7OYmdNDdXx22RD0Jj9jOV9cVtSlBU/CK26Li8AIhWv4Oz/I SbubaD1ZMY/b89usOxT/zWEAUqXENQUr4j6RGYnNB+xpie3B9c5gVfjudD6f3X5j7B6W zYf0JeXz4hyv9LhWAu0E7yFVyEzMOSpiUk7RJR5oiQmuUO4vwrC4aWKfpLCcfim/uhwe aLfhATOD9KWjREcH3oJXz1uUH65MIhBoVvz7nIl79p0OZQyjz3qIe46DfpaT5nS/yr6d NMIn657CO2g69IQS3M+5y+9lrysjX78P9eFisM6xJu54WRCz4UO7X3Dlk96Y0gIjI9yt 2FBQ== X-Gm-Message-State: ANoB5pnLHNJc1h8HkG+7fXqVOPiIvrXFwmrJpDOmnm26vhXYSPXgk/qp jYqdbLcJYRcJTdzg58YlPZZjqw== X-Google-Smtp-Source: AA0mqf5RtmC4SVdyOxL7UJ+lPNbAvIxVBnVYZ5yvegJySAd+TTMaVLm+yOWD7L+39PITwJrZLo3yag== X-Received: by 2002:a17:906:49c2:b0:79f:e0b3:3b9b with SMTP id w2-20020a17090649c200b0079fe0b33b9bmr18729246ejv.378.1668632006474; Wed, 16 Nov 2022 12:53:26 -0800 (PST) Received: from blmsp.fritz.box ([2001:4090:a244:804b:353b:565:addf:3aa7]) by smtp.gmail.com with ESMTPSA id kv17-20020a17090778d100b007aece68483csm6782828ejc.193.2022.11.16.12.53.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 16 Nov 2022 12:53:26 -0800 (PST) From: Markus Schneider-Pargmann To: Chandrasekar Ramakrishnan , Marc Kleine-Budde , Wolfgang Grandegger Cc: linux-can@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Markus Schneider-Pargmann Subject: [PATCH 03/15] can: m_can: Cache tx putidx and transmits in flight Date: Wed, 16 Nov 2022 21:52:56 +0100 Message-Id: <20221116205308.2996556-4-msp@baylibre.com> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221116205308.2996556-1-msp@baylibre.com> References: <20221116205308.2996556-1-msp@baylibre.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-can@vger.kernel.org On peripheral chips every read/write can be costly. Avoid reading easily trackable information and cache them internally. This saves multiple reads. Transmit FIFO put index is cached, this is increased for every time we enqueue a transmit request. The transmits in flight is cached as well. With each transmit request it is increased when reading the finished transmit event it is decreased. A submit limit is cached to avoid submitting too many transmits at once, either because the TX FIFO or the TXE FIFO is limited. This is currently done very conservatively as the minimum of the fifo sizes. This means we can reach FIFO full events but won't drop anything. Signed-off-by: Markus Schneider-Pargmann --- drivers/net/can/m_can/m_can.c | 21 +++++++++++++++------ drivers/net/can/m_can/m_can.h | 5 +++++ 2 files changed, 20 insertions(+), 6 deletions(-) diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c index 4adf03111782..f5bba848bd56 100644 --- a/drivers/net/can/m_can/m_can.c +++ b/drivers/net/can/m_can/m_can.c @@ -1041,6 +1041,7 @@ static int m_can_echo_tx_event(struct net_device *dev) /* ack txe element */ m_can_write(cdev, M_CAN_TXEFA, FIELD_PREP(TXEFA_EFAI_MASK, fgi)); + --cdev->tx_fifo_in_flight; /* update stats */ m_can_tx_update_stats(cdev, msg_mark, timestamp); @@ -1376,6 +1377,14 @@ static void m_can_start(struct net_device *dev) cdev->can.state = CAN_STATE_ERROR_ACTIVE; m_can_enable_all_interrupts(cdev); + + if (cdev->version > 30) { + cdev->tx_fifo_putidx = FIELD_GET(TXFQS_TFQPI_MASK, + m_can_read(cdev, M_CAN_TXFQS)); + cdev->tx_fifo_in_flight = 0; + cdev->tx_fifo_submit_limit = min(cdev->mcfg[MRAM_TXE].num, + cdev->mcfg[MRAM_TXB].num); + } } static int m_can_set_mode(struct net_device *dev, enum can_mode mode) @@ -1589,7 +1598,6 @@ static netdev_tx_t m_can_tx_handler(struct m_can_classdev *cdev) struct sk_buff *skb = cdev->tx_skb; struct id_and_dlc fifo_header; u32 cccr, fdflags; - u32 txfqs; int err; int putidx; @@ -1646,10 +1654,8 @@ static netdev_tx_t m_can_tx_handler(struct m_can_classdev *cdev) } else { /* Transmit routine for version >= v3.1.x */ - txfqs = m_can_read(cdev, M_CAN_TXFQS); - /* Check if FIFO full */ - if (_m_can_tx_fifo_full(txfqs)) { + if (cdev->tx_fifo_in_flight >= cdev->tx_fifo_submit_limit) { /* This shouldn't happen */ netif_stop_queue(dev); netdev_warn(dev, @@ -1665,7 +1671,7 @@ static netdev_tx_t m_can_tx_handler(struct m_can_classdev *cdev) } /* get put index for frame */ - putidx = FIELD_GET(TXFQS_TFQPI_MASK, txfqs); + putidx = cdev->tx_fifo_putidx; /* Construct DLC Field, with CAN-FD configuration. * Use the put index of the fifo as the message marker, @@ -1699,9 +1705,12 @@ static netdev_tx_t m_can_tx_handler(struct m_can_classdev *cdev) /* Enable TX FIFO element to start transfer */ m_can_write(cdev, M_CAN_TXBAR, (1 << putidx)); + ++cdev->tx_fifo_in_flight; + cdev->tx_fifo_putidx = (++cdev->tx_fifo_putidx >= cdev->can.echo_skb_max ? + 0 : cdev->tx_fifo_putidx); /* stop network queue if fifo full */ - if (m_can_tx_fifo_full(cdev) || + if (cdev->tx_fifo_in_flight >= cdev->tx_fifo_submit_limit || m_can_next_echo_skb_occupied(dev, putidx)) netif_stop_queue(dev); else if (cdev->is_peripheral && !cdev->tx_skb && netif_queue_stopped(dev)) diff --git a/drivers/net/can/m_can/m_can.h b/drivers/net/can/m_can/m_can.h index 4c0267f9f297..7464ce56753a 100644 --- a/drivers/net/can/m_can/m_can.h +++ b/drivers/net/can/m_can/m_can.h @@ -92,6 +92,11 @@ struct m_can_classdev { int pm_clock_support; int is_peripheral; + // Store this internally to avoid fetch delays on peripheral chips + int tx_fifo_putidx; + int tx_fifo_in_flight; + int tx_fifo_submit_limit; + struct mram_cfg mcfg[MRAM_CFG_NUM]; }; -- 2.38.1