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=-9.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,T_DKIMWL_WL_HIGH,USER_AGENT_GIT autolearn=unavailable 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 2A42EC28CC2 for ; Thu, 30 May 2019 04:40:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0183525925 for ; Thu, 30 May 2019 04:40:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1559191200; bh=TIFyNDY9FzGlyx5lxUxH4rwVPK55GjuPa0XuZBHjypo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=uwTf/S1NU1iB+WKDXF33bGBPc9H4KSkSD8fbiIm/KEIhmlXh4Zy01RWNwxYRET49z 3Pn0b9GAOpCDhfuV/2qZLuFVYt3efr6q+vdRYnzrgv6JI5C+IOXmOncMeJhiAV5veJ jt2ZVDSTNtyrd00wpX0K/nnbRJLT6LrFEIJHU1aA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729119AbfE3DMg (ORCPT ); Wed, 29 May 2019 23:12:36 -0400 Received: from mail.kernel.org ([198.145.29.99]:49830 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727977AbfE3DLG (ORCPT ); Wed, 29 May 2019 23:11:06 -0400 Received: from localhost (ip67-88-213-2.z213-88-67.customer.algx.net [67.88.213.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 17641244EE; Thu, 30 May 2019 03:11:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1559185865; bh=TIFyNDY9FzGlyx5lxUxH4rwVPK55GjuPa0XuZBHjypo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JchXSAsdQfdl8OArrVSFMELjKYLOZql/j4EPrutzLkT9MyPJGbfbrSvFbWUW2dCXB chqgeaD19Rlu4s5lNfJIaKcfqdkGYHWyAqFRZz0a/wgDOzCVQYo+jEwg9LQ/pORKhl ecJOYUAfRVI0tR/9NCUka+uw0QBkEyG8g/oucOSc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andrea Merello , Ulf Hansson , Sasha Levin Subject: [PATCH 5.1 203/405] mmc: core: make pwrseq_emmc (partially) support sleepy GPIO controllers Date: Wed, 29 May 2019 20:03:21 -0700 Message-Id: <20190530030551.432064473@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190530030540.291644921@linuxfoundation.org> References: <20190530030540.291644921@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [ Upstream commit 002ee28e8b322d4d4b7b83234b5d0f4ebd428eda ] pwrseq_emmc.c implements a HW reset procedure for eMMC chip by driving a GPIO line. It registers the .reset() cb on mmc_pwrseq_ops and it registers a system restart notification handler; both of them perform reset by unconditionally calling gpiod_set_value(). If the eMMC reset line is tied to a GPIO controller whose driver can sleep (i.e. I2C GPIO controller), then the kernel would spit warnings when trying to reset the eMMC chip by means of .reset() mmc_pwrseq_ops cb (that is exactly what I'm seeing during boot). Furthermore, on system reset we would gets to the system restart notification handler with disabled interrupts - local_irq_disable() is called in machine_restart() at least on ARM/ARM64 - and we would be in trouble when the GPIO driver tries to sleep (which indeed doesn't happen here, likely because in my case the machine specific code doesn't call do_kernel_restart(), I guess..). This patch fixes the .reset() cb to make use of gpiod_set_value_cansleep(), so that the eMMC gets reset on boot without complaints, while, since there isn't that much we can do, we avoid register the restart handler if the GPIO controller has a sleepy driver (and we spit a dev_notice() message to let people know).. This had been tested on a downstream 4.9 kernel with backported commit 83f37ee7ba33 ("mmc: pwrseq: Add reset callback to the struct mmc_pwrseq_ops") and commit ae60fb031cf2 ("mmc: core: Don't do eMMC HW reset when resuming the eMMC card"), because I couldn't boot my board otherwise. Maybe worth to RFT. Signed-off-by: Andrea Merello Signed-off-by: Ulf Hansson Signed-off-by: Sasha Levin --- drivers/mmc/core/pwrseq_emmc.c | 38 ++++++++++++++++++---------------- 1 file changed, 20 insertions(+), 18 deletions(-) diff --git a/drivers/mmc/core/pwrseq_emmc.c b/drivers/mmc/core/pwrseq_emmc.c index efb8a7965dd4a..154f4204d58cb 100644 --- a/drivers/mmc/core/pwrseq_emmc.c +++ b/drivers/mmc/core/pwrseq_emmc.c @@ -30,19 +30,14 @@ struct mmc_pwrseq_emmc { #define to_pwrseq_emmc(p) container_of(p, struct mmc_pwrseq_emmc, pwrseq) -static void __mmc_pwrseq_emmc_reset(struct mmc_pwrseq_emmc *pwrseq) -{ - gpiod_set_value(pwrseq->reset_gpio, 1); - udelay(1); - gpiod_set_value(pwrseq->reset_gpio, 0); - udelay(200); -} - static void mmc_pwrseq_emmc_reset(struct mmc_host *host) { struct mmc_pwrseq_emmc *pwrseq = to_pwrseq_emmc(host->pwrseq); - __mmc_pwrseq_emmc_reset(pwrseq); + gpiod_set_value_cansleep(pwrseq->reset_gpio, 1); + udelay(1); + gpiod_set_value_cansleep(pwrseq->reset_gpio, 0); + udelay(200); } static int mmc_pwrseq_emmc_reset_nb(struct notifier_block *this, @@ -50,8 +45,11 @@ static int mmc_pwrseq_emmc_reset_nb(struct notifier_block *this, { struct mmc_pwrseq_emmc *pwrseq = container_of(this, struct mmc_pwrseq_emmc, reset_nb); + gpiod_set_value(pwrseq->reset_gpio, 1); + udelay(1); + gpiod_set_value(pwrseq->reset_gpio, 0); + udelay(200); - __mmc_pwrseq_emmc_reset(pwrseq); return NOTIFY_DONE; } @@ -72,14 +70,18 @@ static int mmc_pwrseq_emmc_probe(struct platform_device *pdev) if (IS_ERR(pwrseq->reset_gpio)) return PTR_ERR(pwrseq->reset_gpio); - /* - * register reset handler to ensure emmc reset also from - * emergency_reboot(), priority 255 is the highest priority - * so it will be executed before any system reboot handler. - */ - pwrseq->reset_nb.notifier_call = mmc_pwrseq_emmc_reset_nb; - pwrseq->reset_nb.priority = 255; - register_restart_handler(&pwrseq->reset_nb); + if (!gpiod_cansleep(pwrseq->reset_gpio)) { + /* + * register reset handler to ensure emmc reset also from + * emergency_reboot(), priority 255 is the highest priority + * so it will be executed before any system reboot handler. + */ + pwrseq->reset_nb.notifier_call = mmc_pwrseq_emmc_reset_nb; + pwrseq->reset_nb.priority = 255; + register_restart_handler(&pwrseq->reset_nb); + } else { + dev_notice(dev, "EMMC reset pin tied to a sleepy GPIO driver; reset on emergency-reboot disabled\n"); + } pwrseq->pwrseq.ops = &mmc_pwrseq_emmc_ops; pwrseq->pwrseq.dev = dev; -- 2.20.1