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 37AC8C77B73 for ; Fri, 14 Apr 2023 18:20:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229479AbjDNSUZ (ORCPT ); Fri, 14 Apr 2023 14:20:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53934 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229693AbjDNSUY (ORCPT ); Fri, 14 Apr 2023 14:20:24 -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 367A79EF7 for ; Fri, 14 Apr 2023 11:20:22 -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 1pnO1p-000341-LU; Fri, 14 Apr 2023 20:20:09 +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 E26861AF3E5; Fri, 14 Apr 2023 18:20:03 +0000 (UTC) Date: Fri, 14 Apr 2023 20:20:01 +0200 From: Marc Kleine-Budde To: Judith Mendez Cc: Chandrasekar Ramakrishnan , Nishanth Menon , Vignesh Raghavendra , Andrew Davis , Wolfgang Grandegger , Rob Herring , Krzysztof Kozlowski , linux-can@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, netdev@vger.kernel.org, Schuyler Patton Subject: Re: [RFC PATCH 5/5] can: m_can: Add hrtimer to generate software interrupt Message-ID: <20230414-bounding-guidance-262dffacd05c-mkl@pengutronix.de> References: <20230413223051.24455-1-jm@ti.com> <20230413223051.24455-6-jm@ti.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="tfenu4g5zij6oym6" Content-Disposition: inline In-Reply-To: <20230413223051.24455-6-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 --tfenu4g5zij6oym6 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On 13.04.2023 17:30:51, Judith Mendez wrote: > Add a 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 Are you sure about the 1ms? > 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 | 24 ++++++++++++++++++++++-- > drivers/net/can/m_can/m_can.h | 3 +++ > drivers/net/can/m_can/m_can_platform.c | 9 +++++++-- > 3 files changed, 32 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 8e83d6963d85..bb9d53f4d3cc 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 > @@ -1584,6 +1585,11 @@ static int m_can_close(struct net_device *dev) > if (!cdev->is_peripheral) > napi_disable(&cdev->napi); > =20 > + if (dev->irq < 0) { > + dev_info(cdev->dev, "Disabling the hrtimer\n"); Make it a dev_dbg() or remove completely. > + hrtimer_cancel(&cdev->hrtimer); > + } > + > m_can_stop(dev); > m_can_clk_stop(cdev); > free_irq(dev->irq, dev); > @@ -1792,6 +1798,19 @@ 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) > +{ > + irqreturn_t ret; never read value? > + struct m_can_classdev *cdev =3D > + container_of(timer, struct m_can_classdev, hrtimer); > + > + ret =3D m_can_isr(0, cdev->net); > + > + hrtimer_forward_now(timer, ns_to_ktime(5 * NSEC_PER_MSEC)); There's ms_to_ktime()....and the "5" doesn't match your patch description. > + > + return HRTIMER_RESTART; > +} > + > static int m_can_open(struct net_device *dev) > { > struct m_can_classdev *cdev =3D netdev_priv(dev); > @@ -1836,8 +1855,9 @@ static int m_can_open(struct net_device *dev) > } > =20 > if (err < 0) { > - netdev_err(dev, "failed to request interrupt\n"); > - goto exit_irq_fail; > + dev_info(cdev->dev, "Enabling the hrtimer\n"); > + cdev->hrtimer.function =3D &hrtimer_callback; > + hrtimer_start(&cdev->hrtimer, ns_to_ktime(0), HRTIMER_MODE_REL_PINNED); IMHO it makes no sense to request an IRQ if the device doesn't have one, and then try to fix up things in the error path. What about this? --- 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 > /* start the m_can controller */ > 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..53e1648e9dab 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 +99,12 @@ 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) { What about the IS_ERR(addr) case? > - ret =3D -EINVAL; > - goto probe_fail; > + if (irq =3D=3D -EPROBE_DEFER) { > + ret =3D -EPROBE_DEFER; > + goto probe_fail; > + } > + dev_info(mcan_class->dev, "Failed to get irq, initialize hrtimer\n"); > + hrtimer_init(&mcan_class->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_P= INNED); I don't like it when polling is unconditionally set up in case of an irq error. I'm not sure if we need an explicit device tree property.... > } > =20 > /* message ram could be shared */ > --=20 > 2.17.1 >=20 > 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 | --tfenu4g5zij6oym6 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEDs2BvajyNKlf9TJQvlAcSiqKBOgFAmQ5mUwACgkQvlAcSiqK BOjFcwf+LKipGSC4WttM1dgCxd5Xp2hAJFwtmQmkb/sewpvvfsMwUV1JKfMHKFeT 00wR3cJxjO+uoKC7tS0+W8TmwX8rjsmbVkkwqVqovFi9Wg7MrKiPedoJolkHhsL3 SiK1J5f7SsqvAo9yEo9PdlIWfNzxgcmtpuGCumUJPaAz0mYazPKI9ICEBjA6/WQk TLcSRh7TPHU8QuuL7le/AHl/9vaOUBPYWSY8tgzwrgvpAzYPvApTTCcElPHKZ6I0 wlwT3KK2ED6LinsZ5HHdCEIGFG7+eN6TGgrxou4gp1jj1/TxhlBt+9tsazAEDbz+ QmHsnFEvtA5kP6UQQW5fvv/TJf1wxQ== =r55h -----END PGP SIGNATURE----- --tfenu4g5zij6oym6--