From patchwork Mon Aug 17 03:52:54 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nicolas Boichat X-Patchwork-Id: 7023091 Return-Path: X-Original-To: patchwork-linux-spi@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 3D3D2C05AC for ; Mon, 17 Aug 2015 03:53:12 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 415882045E for ; Mon, 17 Aug 2015 03:53:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2FDBF2045B for ; Mon, 17 Aug 2015 03:53:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752001AbbHQDxJ (ORCPT ); Sun, 16 Aug 2015 23:53:09 -0400 Received: from mail-pd0-f182.google.com ([209.85.192.182]:33131 "EHLO mail-pd0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751440AbbHQDxI (ORCPT ); Sun, 16 Aug 2015 23:53:08 -0400 Received: by pdrh1 with SMTP id h1so51482307pdr.0 for ; Sun, 16 Aug 2015 20:53:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id; bh=8cx7S7tQknQ6ccLRid7q6qOxpjY40S6lY94W1MMfCuQ=; b=jEDY81fMXrJ+69XBs6Uioz736G2F/InMTagECRcRt7jgdigF37XkOP6+uB/lXTDbVw G3mvGuXc3Jk6naFZfa1g+GNLXqXAeJzoj8pBzIfcvJfG74sdwV23tdqyTwnPyOsq/SDw +9xV5KCrb4f2fDzeNZumE5yi6Epham6FEITqA= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=8cx7S7tQknQ6ccLRid7q6qOxpjY40S6lY94W1MMfCuQ=; b=kYdvTnmxpuWbZMTnCF8lqErVUEbKC4DCuXW1Uoyq0O3+b4K0eIZyCAAf3OUqrPMji0 21F4HX9oZci3xEvv9V2rN7UZnqkPpq7SFkRPml0EELnCwI18/O7cVJk6x6eBYDecCw4x 7D3U2fEbetICsJWrlp2uxSglmjwEMlupwF4AMvm/Gw5rh5TK68Qdn7onfhR63qsYHK5R O550oFRSdHo2A5r23vvIrSFyEUsDvaP5EaLetnsQz4yXOUZ9DmdKkv6jZRh939YGW7gB qG1CCpBvuh6h8SaK0nOMpW0lRRUHIZ2tfxTmDF6XGMM4pN+E8IxtOQmEbKAfrGJ7srRm OxLA== X-Gm-Message-State: ALoCoQk0q+lIOqlTEPARlpkvuKY/SLRHg/duGboa6ppz8Rs4D8aIRZgwEJW/ESU9EWD84PtQbrjh X-Received: by 10.70.43.79 with SMTP id u15mr103965753pdl.84.1439783586946; Sun, 16 Aug 2015 20:53:06 -0700 (PDT) Received: from drinkcat.tpe.corp.google.com ([172.30.210.53]) by smtp.gmail.com with ESMTPSA id ss2sm12793494pbc.45.2015.08.16.20.53.04 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Sun, 16 Aug 2015 20:53:05 -0700 (PDT) From: Nicolas Boichat To: Mark Brown Cc: Kukjin Kim , Krzysztof Kozlowski , linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org Subject: [PATCH v2] spi: bitbang: Replace spinlock by mutex Date: Mon, 17 Aug 2015 11:52:54 +0800 Message-Id: <1439783574-5933-1-git-send-email-drinkcat@chromium.org> X-Mailer: git-send-email 2.5.0.276.gf5e568e Sender: linux-spi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org X-Spam-Status: No, score=-7.5 required=5.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,RP_MATCHES_RCVD,T_DKIM_INVALID,UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP chipselect (in the case of spi-gpio: spi_gpio_chipselect, which calls gpiod_set_raw_value_cansleep) can sleep, so we should not hold a spinlock while calling it from spi_bitbang_setup. This issue was introduced by this commit, which converted spi-gpio to cansleep variants: d9dda5a191 "spi: spi-gpio: Use 'cansleep' variants to access GPIO" Replacing the lock variable by a mutex fixes the issue: This is safe as all instances where the lock is used are called from contexts that can sleep. Finally, update spi-ppc4xx and and spi-s3c24xx to use mutex functions, as they directly hold the lock for similar purpose. Signed-off-by: Nicolas Boichat --- Going the "safer" way and just replacing the spinlock by a mutex. Applies on top of broonie-sound/for-next, and compile-tested on x86-64/arm (allyesconfig) and ppc44x (defconfig+SPI driver), and runtime-tested on an arm platform. Thanks! drivers/spi/spi-bitbang.c | 17 +++++++---------- drivers/spi/spi-ppc4xx.c | 4 ++-- drivers/spi/spi-s3c24xx.c | 4 ++-- include/linux/spi/spi_bitbang.h | 2 +- 4 files changed, 12 insertions(+), 15 deletions(-) diff --git a/drivers/spi/spi-bitbang.c b/drivers/spi/spi-bitbang.c index 840a498..ef43ef5 100644 --- a/drivers/spi/spi-bitbang.c +++ b/drivers/spi/spi-bitbang.c @@ -180,7 +180,6 @@ int spi_bitbang_setup(struct spi_device *spi) { struct spi_bitbang_cs *cs = spi->controller_state; struct spi_bitbang *bitbang; - unsigned long flags; bitbang = spi_master_get_devdata(spi->master); @@ -210,12 +209,12 @@ int spi_bitbang_setup(struct spi_device *spi) */ /* deselect chip (low or high) */ - spin_lock_irqsave(&bitbang->lock, flags); + mutex_lock(&bitbang->lock); if (!bitbang->busy) { bitbang->chipselect(spi, BITBANG_CS_INACTIVE); ndelay(cs->nsecs); } - spin_unlock_irqrestore(&bitbang->lock, flags); + mutex_unlock(&bitbang->lock); return 0; } @@ -255,13 +254,12 @@ static int spi_bitbang_bufs(struct spi_device *spi, struct spi_transfer *t) static int spi_bitbang_prepare_hardware(struct spi_master *spi) { struct spi_bitbang *bitbang; - unsigned long flags; bitbang = spi_master_get_devdata(spi); - spin_lock_irqsave(&bitbang->lock, flags); + mutex_lock(&bitbang->lock); bitbang->busy = 1; - spin_unlock_irqrestore(&bitbang->lock, flags); + mutex_unlock(&bitbang->lock); return 0; } @@ -378,13 +376,12 @@ static int spi_bitbang_transfer_one(struct spi_master *master, static int spi_bitbang_unprepare_hardware(struct spi_master *spi) { struct spi_bitbang *bitbang; - unsigned long flags; bitbang = spi_master_get_devdata(spi); - spin_lock_irqsave(&bitbang->lock, flags); + mutex_lock(&bitbang->lock); bitbang->busy = 0; - spin_unlock_irqrestore(&bitbang->lock, flags); + mutex_unlock(&bitbang->lock); return 0; } @@ -427,7 +424,7 @@ int spi_bitbang_start(struct spi_bitbang *bitbang) if (!master || !bitbang->chipselect) return -EINVAL; - spin_lock_init(&bitbang->lock); + mutex_init(&bitbang->lock); if (!master->mode_bits) master->mode_bits = SPI_CPOL | SPI_CPHA | bitbang->flags; diff --git a/drivers/spi/spi-ppc4xx.c b/drivers/spi/spi-ppc4xx.c index 54fb984..dd3d0a2 100644 --- a/drivers/spi/spi-ppc4xx.c +++ b/drivers/spi/spi-ppc4xx.c @@ -210,12 +210,12 @@ static int spi_ppc4xx_setupxfer(struct spi_device *spi, struct spi_transfer *t) if (in_8(&hw->regs->cdm) != cdm) out_8(&hw->regs->cdm, cdm); - spin_lock(&hw->bitbang.lock); + mutex_lock(&hw->bitbang.lock); if (!hw->bitbang.busy) { hw->bitbang.chipselect(spi, BITBANG_CS_INACTIVE); /* Need to ndelay here? */ } - spin_unlock(&hw->bitbang.lock); + mutex_unlock(&hw->bitbang.lock); return 0; } diff --git a/drivers/spi/spi-s3c24xx.c b/drivers/spi/spi-s3c24xx.c index f36bc32..4e7d1bf 100644 --- a/drivers/spi/spi-s3c24xx.c +++ b/drivers/spi/spi-s3c24xx.c @@ -198,12 +198,12 @@ static int s3c24xx_spi_setup(struct spi_device *spi) if (ret) return ret; - spin_lock(&hw->bitbang.lock); + mutex_lock(&hw->bitbang.lock); if (!hw->bitbang.busy) { hw->bitbang.chipselect(spi, BITBANG_CS_INACTIVE); /* need to ndelay for 0.5 clocktick ? */ } - spin_unlock(&hw->bitbang.lock); + mutex_unlock(&hw->bitbang.lock); return 0; } diff --git a/include/linux/spi/spi_bitbang.h b/include/linux/spi/spi_bitbang.h index 85578d4..154788e 100644 --- a/include/linux/spi/spi_bitbang.h +++ b/include/linux/spi/spi_bitbang.h @@ -4,7 +4,7 @@ #include struct spi_bitbang { - spinlock_t lock; + struct mutex lock; u8 busy; u8 use_dma; u8 flags; /* extra spi->mode support */