[PATCH 3.19 069/175] mmc: sdhci-pxav3: fix race between runtime pm and irq

Greg Kroah-Hartman
2015-03-04T06:20:31Z

From: Jisheng Zhang <jszhang@marvell.com>

commit 3bb10f60933e84abfe2be69f60b3486f9b96348b upstream.

This patch is to fix a race condition that may cause an unhandled irq,
which results in big sdhci interrupt numbers and endless "mmc1: got irq
while runtime suspended" msgs before v3.15.

Consider following scenario:

CPU0 CPU1
sdhci_pxav3_runtime_suspend()
spin_lock_irqsave(&host->lock, flags);
sdhci_irq()
spining on the &host->lock
host->runtime_suspended = true;
spin_unlock_irqrestore(&host->lock, flags);
get the &host->lock
runtime_suspended is true now
return IRQ_NONE;

Fix this race by using the core sdhci.c supplied sdhci_runtime_suspend_host()
in runtime suspend hook which will disable card interrupts. We also use the
sdhci_runtime_resume_host() in the runtime resume hook accordingly.

Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/mmc/host/sdhci-pxav3.c | 15 +++++----------
1 file changed, 5 insertions(+), 10 deletions(-)

--- a/drivers/mmc/host/sdhci-pxav3.c
+++ b/drivers/mmc/host/sdhci-pxav3.c
@@ -458,11 +458,11 @@ static int sdhci_pxav3_runtime_suspend(s
struct sdhci_host *host = dev_get_drvdata(dev);
struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
struct sdhci_pxa *pxa = pltfm_host->priv;
- unsigned long flags;
+ int ret;

- spin_lock_irqsave(&host->lock, flags);
- host->runtime_suspended = true;
- spin_unlock_irqrestore(&host->lock, flags);
+ ret = sdhci_runtime_suspend_host(host);
+ if (ret)
+ return ret;

clk_disable_unprepare(pxa->clk_io);
if (!IS_ERR(pxa->clk_core))
@@ -476,17 +476,12 @@ static int sdhci_pxav3_runtime_resume(st
struct sdhci_host *host = dev_get_drvdata(dev);
struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
struct sdhci_pxa *pxa = pltfm_host->priv;
- unsigned long flags;

clk_prepare_enable(pxa->clk_io);
if (!IS_ERR(pxa->clk_core))
clk_prepare_enable(pxa->clk_core);

- spin_lock_irqsave(&host->lock, flags);
- host->runtime_suspended = false;
- spin_unlock_irqrestore(&host->lock, flags);
-
- return 0;
+ return sdhci_runtime_resume_host(host);
}
#endif