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 345E9C77B72 for ; Thu, 20 Apr 2023 09:40:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233895AbjDTJkV (ORCPT ); Thu, 20 Apr 2023 05:40:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51608 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233961AbjDTJjq (ORCPT ); Thu, 20 Apr 2023 05:39:46 -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 3CB775B81 for ; Thu, 20 Apr 2023 02:38:06 -0700 (PDT) Received: from moin.white.stw.pengutronix.de ([2a0a:edc0:0:b01:1d::7b] 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 1ppQjR-0008Cs-Mx; Thu, 20 Apr 2023 11:37:37 +0200 Received: from pengutronix.de (unknown [172.20.34.65]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (prime256v1) server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) (Authenticated sender: mkl-all@blackshift.org) by smtp.blackshift.org (Postfix) with ESMTPSA id A56391B3CD6; Thu, 20 Apr 2023 09:37:35 +0000 (UTC) Date: Thu, 20 Apr 2023 11:37:35 +0200 From: Marc Kleine-Budde To: Judith Mendez Cc: Chandrasekar Ramakrishnan , Wolfgang Grandegger , "David S . Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Schuyler Patton , Nishanth Menon , Vignesh Raghavendra , Tero Kristo , Rob Herring , Krzysztof Kozlowski , Oliver Hartkopp , linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-can@vger.kernel.org, netdev@vger.kernel.org Subject: Re: [PATCH 1/4] can: m_can: Add hrtimer to generate software interrupt Message-ID: <20230420-unlikable-overstep-6ad655c5bbdc-mkl@pengutronix.de> References: <20230419223323.20384-1-jm@ti.com> <20230419223323.20384-2-jm@ti.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="ikdkjwlh4qdhgblk" Content-Disposition: inline In-Reply-To: <20230419223323.20384-2-jm@ti.com> X-SA-Exim-Connect-IP: 2a0a:edc0:0:b01:1d::7b 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: devicetree@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org --ikdkjwlh4qdhgblk Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On 19.04.2023 17:33:20, Judith Mendez wrote: > Add an hrtimer to MCAN struct. Each MCAN will have its own > hrtimer instantiated if there is no hardware interrupt found. >=20 > 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. >=20 > Signed-off-by: Judith Mendez > --- > drivers/net/can/m_can/m_can.c | 30 ++++++++++++++++++++++++-- > drivers/net/can/m_can/m_can.h | 3 +++ > drivers/net/can/m_can/m_can_platform.c | 13 +++++++++-- > 3 files changed, 42 insertions(+), 4 deletions(-) >=20 > diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c > index a5003435802b..8784bdea300a 100644 > --- a/drivers/net/can/m_can/m_can.c > +++ b/drivers/net/can/m_can/m_can.c > @@ -23,6 +23,7 @@ > #include > #include > #include > +#include > =20 > #include "m_can.h" > =20 > @@ -1587,6 +1588,11 @@ static int m_can_close(struct net_device *dev) > if (!cdev->is_peripheral) > napi_disable(&cdev->napi); > =20 > + if (dev->irq < 0) { > + dev_dbg(cdev->dev, "Disabling the hrtimer\n"); > + hrtimer_cancel(&cdev->hrtimer); > + } > + > m_can_stop(dev); > m_can_clk_stop(cdev); > free_irq(dev->irq, dev); > @@ -1793,6 +1799,18 @@ static netdev_tx_t m_can_start_xmit(struct sk_buff= *skb, > return NETDEV_TX_OK; > } > =20 > +enum hrtimer_restart hrtimer_callback(struct hrtimer *timer) > +{ > + struct m_can_classdev *cdev =3D > + container_of(timer, struct m_can_classdev, hrtimer); > + > + m_can_isr(0, cdev->net); > + > + hrtimer_forward_now(timer, ms_to_ktime(1)); > + > + return HRTIMER_RESTART; > +} > + > static int m_can_open(struct net_device *dev) > { > struct m_can_classdev *cdev =3D netdev_priv(dev); > @@ -1827,13 +1845,21 @@ static int m_can_open(struct net_device *dev) > } > =20 > INIT_WORK(&cdev->tx_work, m_can_tx_work_queue); > - > err =3D request_threaded_irq(dev->irq, NULL, m_can_isr, > IRQF_ONESHOT, > dev->name, dev); > + nitpick: Please remove these 2 newline changes. > } else { > - err =3D request_irq(dev->irq, m_can_isr, IRQF_SHARED, dev->name, > + if (dev->irq > 0) { Please follow the kernel coding style and use a space not a tab after the closing ")" of the "if". > + err =3D request_irq(dev->irq, m_can_isr, IRQF_SHARED, dev->name, > dev); > + } > + > + else { Please use kernel coding style: "} else {" > + dev_dbg(cdev->dev, "Enabling the hrtimer\n"); > + cdev->hrtimer.function =3D &hrtimer_callback; > + hrtimer_start(&cdev->hrtimer, ns_to_ktime(0), HRTIMER_MODE_REL_PINNED= ); > + } I think there's no need to have nested else branches, what about this approach? --- a/drivers/net/can/m_can/m_can.c +++ b/drivers/net/can/m_can/m_can.c @@ -1831,9 +1831,11 @@ static int m_can_open(struct net_device *dev) err =3D request_threaded_irq(dev->irq, NULL, m_can_isr, IRQF_ONESHOT, dev->name, dev); - } else { + } else if (dev->irq) { err =3D request_irq(dev->irq, m_can_isr, IRQF_SHARED, dev-= >name, dev); + } else { + // polling } =20 if (err < 0) { > } > =20 > 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..ed046d77fdb9 100644 > --- a/drivers/net/can/m_can/m_can.h > +++ b/drivers/net/can/m_can/m_can.h > @@ -28,6 +28,7 @@ > #include > #include > #include > +#include > =20 > /* m_can lec values */ > enum m_can_lec_type { > @@ -93,6 +94,8 @@ struct m_can_classdev { > int is_peripheral; > =20 > struct mram_cfg mcfg[MRAM_CFG_NUM]; > + > + struct hrtimer hrtimer; > }; > =20 > 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_c= an/m_can_platform.c > index 9c1dcf838006..7540db74b7d0 100644 > --- a/drivers/net/can/m_can/m_can_platform.c > +++ b/drivers/net/can/m_can/m_can_platform.c > @@ -7,6 +7,7 @@ > =20 > #include > #include > +#include > =20 > #include "m_can.h" > =20 > @@ -98,8 +99,16 @@ static int m_can_plat_probe(struct platform_device *pd= ev) > addr =3D devm_platform_ioremap_resource_byname(pdev, "m_can"); > irq =3D platform_get_irq_byname(pdev, "int0"); > if (IS_ERR(addr) || irq < 0) { > - ret =3D -EINVAL; > - goto probe_fail; > + if (irq =3D=3D -EPROBE_DEFER) { > + ret =3D -EPROBE_DEFER; > + goto probe_fail; > + } > + if (IS_ERR(addr)) { > + ret =3D PTR_ERR(addr); > + goto probe_fail; > + } > + dev_dbg(mcan_class->dev, "Failed to get irq, initialize hrtimer\n"); > + hrtimer_init(&mcan_class->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_P= INNED); Looks better. Please remove the outer "if (IS_ERR(addr) || irq < 0)" and move the error checking directly after "addr =3D devm_platform_ioremap_reso= urce_byname()". What do you think about introducing the "poll-interval" property and only enable polling if it is set? > } > =20 > /* message ram could be shared */ > --=20 > 2.17.1 >=20 > regards, Marc --=20 Pengutronix e.K. | Marc Kleine-Budde | Embedded Linux | https://www.pengutronix.de | Vertretung N=C3=BCrnberg | Phone: +49-5121-206917-129 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-9 | --ikdkjwlh4qdhgblk Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEDs2BvajyNKlf9TJQvlAcSiqKBOgFAmRBB9wACgkQvlAcSiqK BOg0zgf8CBj+E5MKzrz5bNRXj0BWuK0IdUDA6yeaHlfkfp2NkkBFuJt+CkVPvX0y e+kKRBxqpIlZ+fPxzMVqyP0AuGHn4+9wtfMngfEvtTi/BlhuBkQMRQYVTPcUEjwI bNggMFPpIj0Re1c15cICUOBFLlmTUvpD5mC08LprvOtLKF78R336dOwVkrM+gNjF ke3ickmvQjQFlS370Ge6YeABRISdipavv7e0xvoWt613yTCnXShppLIGfQm7d6rF Cs7GTVwYLEmtepUK2GwjKrKLRF4N6CfHezmTq/Y7e0ztnEUeE4IOqicFxoLaAsRj ++iDnGMinJGDZXBdwVY5EKos9lehIQ== =9hcv -----END PGP SIGNATURE----- --ikdkjwlh4qdhgblk--