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 0C5B6C77B7A for ; Wed, 24 May 2023 21:20:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229447AbjEXVUx (ORCPT ); Wed, 24 May 2023 17:20:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56150 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229658AbjEXVUw (ORCPT ); Wed, 24 May 2023 17:20:52 -0400 Received: from fllv0015.ext.ti.com (fllv0015.ext.ti.com [198.47.19.141]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8F9B2132; Wed, 24 May 2023 14:20:45 -0700 (PDT) Received: from lelv0265.itg.ti.com ([10.180.67.224]) by fllv0015.ext.ti.com (8.15.2/8.15.2) with ESMTP id 34OLKFGp073915; Wed, 24 May 2023 16:20:15 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1684963215; bh=Anjqsreye1B4ntfPOBld6ZtkWYZAP0DjCad9lmUAkGE=; h=Date:Subject:To:CC:References:From:In-Reply-To; b=uQVDZHbmTkpA/mH3J5yqgWVx2chzOoe0h/S9rI0FvmWZg2RLr8kCNiD+0QI/l7vN7 GHz9zCK1uhebWqdfMjN3GVdd85YboWrt2a2CcVyggl1AIqVb6lrYn8rF+RPNqE36Ze v3G0ScixR4azV1CH8ODECmuYMLsxDuRC9nEG+D4A= Received: from DLEE102.ent.ti.com (dlee102.ent.ti.com [157.170.170.32]) by lelv0265.itg.ti.com (8.15.2/8.15.2) with ESMTPS id 34OLKFcM030529 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Wed, 24 May 2023 16:20:15 -0500 Received: from DLEE109.ent.ti.com (157.170.170.41) by DLEE102.ent.ti.com (157.170.170.32) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2507.23; Wed, 24 May 2023 16:20:15 -0500 Received: from lelv0327.itg.ti.com (10.180.67.183) by DLEE109.ent.ti.com (157.170.170.41) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2507.23 via Frontend Transport; Wed, 24 May 2023 16:20:15 -0500 Received: from [128.247.81.105] (ileaxei01-snat.itg.ti.com [10.180.69.5]) by lelv0327.itg.ti.com (8.15.2/8.15.2) with ESMTP id 34OLKFEC109050; Wed, 24 May 2023 16:20:15 -0500 Message-ID: <351cbfcc-a3be-ff23-ead7-5fc38013ecbb@ti.com> Date: Wed, 24 May 2023 16:20:15 -0500 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.11.0 Subject: Re: [PATCH v7 2/2] can: m_can: Add hrtimer to generate software interrupt Content-Language: en-US To: Marc Kleine-Budde CC: Chandrasekar Ramakrishnan , , Wolfgang Grandegger , "David S . Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , , , Schuyler Patton , Tero Kristo , Rob Herring , Krzysztof Kozlowski , Conor Dooley , , Oliver Hartkopp , Tony Lindgren References: <20230523023749.4526-1-jm@ti.com> <20230523023749.4526-3-jm@ti.com> <20230523-crawlers-cupbearer-7a7cbfed010b-mkl@pengutronix.de> From: Judith Mendez In-Reply-To: <20230523-crawlers-cupbearer-7a7cbfed010b-mkl@pengutronix.de> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Precedence: bulk List-ID: X-Mailing-List: linux-can@vger.kernel.org Hello Marc, On 5/23/23 1:35 AM, Marc Kleine-Budde wrote: > On 22.05.2023 21:37:49, Judith Mendez wrote: >> Add an hrtimer to MCAN class device. Each MCAN will have its own >> hrtimer instantiated if there is no hardware interrupt found in >> device tree M_CAN node. > > Please add a sentence why you introduce polling mode, i.e. there are > SoCs where the M_CAN interrupt is not available on the CPUs (which are > running Linux). Sure, I can do that, thanks. > >> The hrtimer will generate a software interrupt every 1 ms. In >> hrtimer callback, we check if there is a transaction pending by >> reading a register, then process by calling the isr if there is. >> >> Signed-off-by: Judith Mendez >> --- >> Changelog: >> v7: >> - Clean up m_can_platform.c if/else section after removing poll-interval >> - Remove poll-interval from patch description >> v6: >> - Move hrtimer stop/start function calls to m_can_open and m_can_close to >> support power suspend/resume >> v5: >> - Change dev_dbg to dev_info if hardware interrupt exists and polling >> is enabled >> v4: >> - No changes >> v3: >> - Create a define for 1 ms polling interval >> - Change plarform_get_irq to optional to not print error msg >> v2: >> - Add functionality to check for 'poll-interval' property in MCAN node >> - Add 'polling' flag in driver to check if device is using polling method >> - Check for timer polling and hardware interrupt cases, default to >> hardware interrupt method >> - Change ns_to_ktime() to ms_to_ktime() >> --- >> drivers/net/can/m_can/m_can.c | 33 ++++++++++++++++++++++++-- >> drivers/net/can/m_can/m_can.h | 4 ++++ >> drivers/net/can/m_can/m_can_platform.c | 25 ++++++++++++++++--- >> 3 files changed, 57 insertions(+), 5 deletions(-) >> >> diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c >> index a5003435802b..f273d989bdff 100644 >> --- a/drivers/net/can/m_can/m_can.c >> +++ b/drivers/net/can/m_can/m_can.c >> @@ -11,6 +11,7 @@ >> #include >> #include >> #include >> +#include >> #include >> #include >> #include >> @@ -308,6 +309,9 @@ enum m_can_reg { >> #define TX_EVENT_MM_MASK GENMASK(31, 24) >> #define TX_EVENT_TXTS_MASK GENMASK(15, 0) >> >> +/* Hrtimer polling interval */ >> +#define HRTIMER_POLL_INTERVAL 1 >> + >> /* 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. >> @@ -895,7 +899,7 @@ static int m_can_handle_bus_errors(struct net_device *dev, u32 irqstatus, >> netdev_dbg(dev, "Arbitration phase error detected\n"); >> work_done += m_can_handle_lec_err(dev, lec); >> } >> - >> + > > Unrelated change. I've send a separate patch to fix the problem. Sorry about this, this was not intentional. > >> if (is_lec_err(dlec)) { >> netdev_dbg(dev, "Data phase error detected\n"); >> work_done += m_can_handle_lec_err(dev, dlec); >> @@ -1414,6 +1418,12 @@ static int m_can_start(struct net_device *dev) >> >> m_can_enable_all_interrupts(cdev); >> >> + if (cdev->polling) { >> + dev_dbg(cdev->dev, "Start hrtimer\n"); >> + hrtimer_start(&cdev->hrtimer, ms_to_ktime(HRTIMER_POLL_INTERVAL), >> + HRTIMER_MODE_REL_PINNED); >> + } >> + >> return 0; >> } >> >> @@ -1571,6 +1581,11 @@ static void m_can_stop(struct net_device *dev) >> /* disable all interrupts */ >> m_can_disable_all_interrupts(cdev); >> >> + if (cdev->polling) { >> + dev_dbg(cdev->dev, "Disabling the hrtimer\n"); >> + hrtimer_cancel(&cdev->hrtimer); >> + } >> + > > This might be a racy. Please move the disabling of the hrtimer before > disabling all interrupts. This makes it also symmetric with respect to > m_can_start(). This makes sense. > >> /* Set init mode to disengage from the network */ >> m_can_config_endisable(cdev, true); >> >> @@ -1793,6 +1808,18 @@ static netdev_tx_t m_can_start_xmit(struct sk_buff *skb, >> return NETDEV_TX_OK; >> } >> >> +static enum hrtimer_restart hrtimer_callback(struct hrtimer *timer) >> +{ >> + struct m_can_classdev *cdev = container_of(timer, struct >> + m_can_classdev, hrtimer); >> + >> + m_can_isr(0, cdev->net); >> + >> + hrtimer_forward_now(timer, ms_to_ktime(HRTIMER_POLL_INTERVAL)); >> + >> + return HRTIMER_RESTART; >> +} >> + >> static int m_can_open(struct net_device *dev) >> { >> struct m_can_classdev *cdev = netdev_priv(dev); >> @@ -1831,9 +1858,11 @@ static int m_can_open(struct net_device *dev) >> err = request_threaded_irq(dev->irq, NULL, m_can_isr, >> IRQF_ONESHOT, >> dev->name, dev); >> - } else { >> + } else if (!cdev->polling) { >> err = request_irq(dev->irq, m_can_isr, IRQF_SHARED, dev->name, >> dev); >> + } else { >> + cdev->hrtimer.function = &hrtimer_callback; > > I think you can move this assignment to m_can_class_register(). We only > need to set the function once. Great idea! > >> } >> >> if (err < 0) { >> diff --git a/drivers/net/can/m_can/m_can.h b/drivers/net/can/m_can/m_can.h >> index a839dc71dc9b..e9db5cce4e68 100644 >> --- a/drivers/net/can/m_can/m_can.h >> +++ b/drivers/net/can/m_can/m_can.h >> @@ -15,6 +15,7 @@ >> #include >> #include >> #include >> +#include >> #include >> #include >> #include >> @@ -93,6 +94,9 @@ struct m_can_classdev { >> int is_peripheral; >> >> struct mram_cfg mcfg[MRAM_CFG_NUM]; >> + >> + struct hrtimer hrtimer; >> + bool polling; >> }; >> >> struct m_can_classdev *m_can_class_allocate_dev(struct device *dev, int sizeof_priv); >> diff --git a/drivers/net/can/m_can/m_can_platform.c b/drivers/net/can/m_can/m_can_platform.c >> index 94dc82644113..b639c9e645d3 100644 >> --- a/drivers/net/can/m_can/m_can_platform.c >> +++ b/drivers/net/can/m_can/m_can_platform.c >> @@ -5,6 +5,7 @@ >> // >> // Copyright (C) 2018-19 Texas Instruments Incorporated - http://www.ti.com/ >> >> +#include >> #include >> #include >> >> @@ -96,12 +97,30 @@ static int m_can_plat_probe(struct platform_device *pdev) >> goto probe_fail; >> >> addr = devm_platform_ioremap_resource_byname(pdev, "m_can"); >> - irq = platform_get_irq_byname(pdev, "int0"); > > I think irq will be uninitialized after this change. Although the > compiler doesn't complain :( Agreed, I did notice this when testing. But is it an issue? > > BTW: I think we don't need the "polling" variable in the priv. We can > make use of "irq". "irq" being 0 means use polling. True, but is using the polling flag easier for the user to read? > >> - if (IS_ERR(addr) || irq < 0) { >> - ret = -EINVAL; >> + if (IS_ERR(addr)) { >> + ret = PTR_ERR(addr); >> goto probe_fail; >> } >> >> + if (device_property_present(mcan_class->dev, "interrupts") || >> + device_property_present(mcan_class->dev, "interrupt-names")) { >> + irq = platform_get_irq_byname(pdev, "int0"); >> + mcan_class->polling = false; >> + if (irq == -EPROBE_DEFER) { >> + ret = -EPROBE_DEFER; >> + goto probe_fail; >> + } >> + if (irq < 0) { >> + ret = -ENXIO; EINVAL? Wouldn't ENXIO (No such device or address) be more appropriate than invalid argument? > > Please return the original error code. > >> + goto probe_fail; >> + } >> + } else { >> + mcan_class->polling = true; >> + dev_dbg(mcan_class->dev, "Polling enabled, initialize hrtimer"); >> + hrtimer_init(&mcan_class->hrtimer, CLOCK_MONOTONIC, >> + HRTIMER_MODE_REL_PINNED); >> + } >> + >> /* message ram could be shared */ >> res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "message_ram"); >> if (!res) { ~Judith