From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andreas Fenkart Subject: [PATCH v14 4/6] mmc: omap_hsmmc: abort runtime suspend if pending sdio irq detected Date: Thu, 29 May 2014 10:28:03 +0200 Message-ID: <1401352085-22781-5-git-send-email-afenkart@gmail.com> References: <1401352085-22781-1-git-send-email-afenkart@gmail.com> Return-path: In-Reply-To: <1401352085-22781-1-git-send-email-afenkart@gmail.com> Sender: linux-doc-owner@vger.kernel.org To: Tony Lindgren Cc: Chris Ball , Grant Likely , Felipe Balbi , Balaji T K , Andreas Mueller , Sebastian Reichel , zonque@gmail.com, galak@codeaurora.org, linux-doc@vger.kernel.org, linux-mmc@vger.kernel.org, linux-omap@vger.kernel.org, Andreas Fenkart List-Id: linux-mmc@vger.kernel.org On multicores, an sdio irq handler could be running in parallel to runtime suspend. In the worst case it could be waiting for the spinlock held by the runtime suspend. When runtime suspend is complete and the functional clock (fclk) turned off, the irq handler will continue and cause a SIGBUS on the first register access. Acked-by: Balaji T K Signed-off-by: Andreas Fenkart diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c index b8be438..2408ec9 100644 --- a/drivers/mmc/host/omap_hsmmc.c +++ b/drivers/mmc/host/omap_hsmmc.c @@ -107,6 +107,9 @@ #define SRD (1 << 26) #define SOFTRESET (1 << 1) +/* PSTATE */ +#define DLEV_DAT(x) (1 << (20 + (x))) + /* Interrupt masks for IE and ISE register */ #define CC_EN (1 << 0) #define TC_EN (1 << 1) @@ -2397,6 +2400,7 @@ static int omap_hsmmc_runtime_suspend(struct device *dev) { struct omap_hsmmc_host *host; unsigned long flags; + int ret = 0; host = platform_get_drvdata(to_platform_device(dev)); omap_hsmmc_context_save(host); @@ -2408,14 +2412,29 @@ static int omap_hsmmc_runtime_suspend(struct device *dev) /* disable sdio irq handling to prevent race */ OMAP_HSMMC_WRITE(host->base, ISE, 0); OMAP_HSMMC_WRITE(host->base, IE, 0); - OMAP_HSMMC_WRITE(host->base, STAT, STAT_CLEAR); + + if (!(OMAP_HSMMC_READ(host->base, PSTATE) & DLEV_DAT(1))) { + /* + * dat1 line low, pending sdio irq + * race condition: possible irq handler running on + * multi-core, abort + */ + dev_dbg(dev, "pending sdio irq, abort suspend\n"); + OMAP_HSMMC_WRITE(host->base, STAT, STAT_CLEAR); + OMAP_HSMMC_WRITE(host->base, ISE, CIRQ_EN); + OMAP_HSMMC_WRITE(host->base, IE, CIRQ_EN); + pm_runtime_mark_last_busy(dev); + ret = -EBUSY; + goto abort; + } WARN_ON(host->flags & HSMMC_WAKE_IRQ_ENABLED); enable_irq(host->wake_irq); host->flags |= HSMMC_WAKE_IRQ_ENABLED; } +abort: spin_unlock_irqrestore(&host->irq_lock, flags); - return 0; + return ret; } static int omap_hsmmc_runtime_resume(struct device *dev) -- 1.7.10.4