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 X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4E0B5C43214 for ; Thu, 19 Aug 2021 13:39:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3A70E610A1 for ; Thu, 19 Aug 2021 13:39:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240337AbhHSNk0 (ORCPT ); Thu, 19 Aug 2021 09:40:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59904 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240284AbhHSNkS (ORCPT ); Thu, 19 Aug 2021 09:40:18 -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 F2773C0613D9 for ; Thu, 19 Aug 2021 06:39:39 -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 1mGiGg-0004sO-7G for linux-can@vger.kernel.org; Thu, 19 Aug 2021 15:39:38 +0200 Received: from dspam.blackshift.org (localhost [127.0.0.1]) by bjornoya.blackshift.org (Postfix) with SMTP id 9054F66A874 for ; Thu, 19 Aug 2021 13:39:33 +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 ECDHE (P-384) server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by bjornoya.blackshift.org (Postfix) with ESMTPS id ECFF266A82C; Thu, 19 Aug 2021 13:39:24 +0000 (UTC) Received: from blackshift.org (localhost [::1]) by hardanger.blackshift.org (OpenSMTPD) with ESMTP id 7e1e2a6c; Thu, 19 Aug 2021 13:39:15 +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, Matt Kline , Marc Kleine-Budde Subject: [PATCH net-next 14/22] can: m_can: Batch FIFO reads during CAN receive Date: Thu, 19 Aug 2021 15:39:05 +0200 Message-Id: <20210819133913.657715-15-mkl@pengutronix.de> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210819133913.657715-1-mkl@pengutronix.de> References: <20210819133913.657715-1-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: linux-can@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-can@vger.kernel.org From: Matt Kline On peripherals communicating over a relatively slow SPI line (e.g. tcan4x5x), individual transfers have high fixed costs. This causes the driver to spend most of its time waiting between transfers and severely limits throughput. Reduce these overheads by reading more than one word at a time. Writing could get a similar treatment in follow-on commits. Link: https://lore.kernel.org/r/20210817050853.14875-3-matt@bitbashing.io Signed-off-by: Matt Kline [mkl: remove __packed from struct id_and_dlc] Signed-off-by: Marc Kleine-Budde --- drivers/net/can/m_can/m_can.c | 51 +++++++++++++++++++---------------- 1 file changed, 28 insertions(+), 23 deletions(-) diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c index 8922ca0f8e94..fbd32b48d265 100644 --- a/drivers/net/can/m_can/m_can.c +++ b/drivers/net/can/m_can/m_can.c @@ -309,6 +309,15 @@ enum m_can_reg { #define TX_EVENT_MM_MASK GENMASK(31, 24) #define TX_EVENT_TXTS_MASK GENMASK(15, 0) +/* The ID and DLC registers are adjacent in M_CAN FIFO memory, + * and we can save a (potentially slow) bus round trip by combining + * reads and writes to them. + */ +struct id_and_dlc { + u32 id; + u32 dlc; +}; + static inline u32 m_can_read(struct m_can_classdev *cdev, enum m_can_reg reg) { return cdev->ops->read_reg(cdev, reg); @@ -464,17 +473,18 @@ static int m_can_read_fifo(struct net_device *dev, u32 rxfs) struct m_can_classdev *cdev = netdev_priv(dev); struct canfd_frame *cf; struct sk_buff *skb; - u32 id, fgi, dlc; + struct id_and_dlc fifo_header; + u32 fgi; u32 timestamp = 0; - int i, err; + int err; /* calculate the fifo get index for where to read data */ fgi = FIELD_GET(RXFS_FGI_MASK, rxfs); - err = m_can_fifo_read(cdev, fgi, M_CAN_FIFO_DLC, &dlc, 1); + err = m_can_fifo_read(cdev, fgi, M_CAN_FIFO_ID, &fifo_header, 2); if (err) goto out_fail; - if (dlc & RX_BUF_FDF) + if (fifo_header.dlc & RX_BUF_FDF) skb = alloc_canfd_skb(dev, &cf); else skb = alloc_can_skb(dev, (struct can_frame **)&cf); @@ -483,36 +493,31 @@ static int m_can_read_fifo(struct net_device *dev, u32 rxfs) return 0; } - if (dlc & RX_BUF_FDF) - cf->len = can_fd_dlc2len((dlc >> 16) & 0x0F); + if (fifo_header.dlc & RX_BUF_FDF) + cf->len = can_fd_dlc2len((fifo_header.dlc >> 16) & 0x0F); else - cf->len = can_cc_dlc2len((dlc >> 16) & 0x0F); - - err = m_can_fifo_read(cdev, fgi, M_CAN_FIFO_ID, &id, 1); - if (err) - goto out_fail; + cf->len = can_cc_dlc2len((fifo_header.dlc >> 16) & 0x0F); - if (id & RX_BUF_XTD) - cf->can_id = (id & CAN_EFF_MASK) | CAN_EFF_FLAG; + if (fifo_header.id & RX_BUF_XTD) + cf->can_id = (fifo_header.id & CAN_EFF_MASK) | CAN_EFF_FLAG; else - cf->can_id = (id >> 18) & CAN_SFF_MASK; + cf->can_id = (fifo_header.id >> 18) & CAN_SFF_MASK; - if (id & RX_BUF_ESI) { + if (fifo_header.id & RX_BUF_ESI) { cf->flags |= CANFD_ESI; netdev_dbg(dev, "ESI Error\n"); } - if (!(dlc & RX_BUF_FDF) && (id & RX_BUF_RTR)) { + if (!(fifo_header.dlc & RX_BUF_FDF) && (fifo_header.id & RX_BUF_RTR)) { cf->can_id |= CAN_RTR_FLAG; } else { - if (dlc & RX_BUF_BRS) + if (fifo_header.dlc & RX_BUF_BRS) cf->flags |= CANFD_BRS; - for (i = 0; i < cf->len; i += 4) { - err = m_can_fifo_read(cdev, fgi, M_CAN_FIFO_DATA(i / 4), cf->data + i, 1); - if (err) - goto out_fail; - } + err = m_can_fifo_read(cdev, fgi, M_CAN_FIFO_DATA(0), + cf->data, DIV_ROUND_UP(cf->len, 4)); + if (err) + goto out_fail; } /* acknowledge rx fifo 0 */ @@ -521,7 +526,7 @@ static int m_can_read_fifo(struct net_device *dev, u32 rxfs) stats->rx_packets++; stats->rx_bytes += cf->len; - timestamp = FIELD_GET(RX_BUF_RXTS_MASK, dlc); + timestamp = FIELD_GET(RX_BUF_RXTS_MASK, fifo_header.dlc); m_can_receive_skb(cdev, skb, timestamp); -- 2.32.0