[PATCH v3 1/2] mmc: sdhci: fix abort due to missing runtime PM

Stefan Agner
2015-05-21T07:15:03Z

When using i.MX ESDHC driver, while entering suspend while the device
is in runtime PM, the sdhci_(suspend|resume)_host function are called
with disabled clocks. Since this functions access the SDHC host
registers, this leads to an external abort on Vybrid SoC:

[ 37.772967] Unhandled fault: imprecise external abort (0x1c06) at 0x76f5f000
[ 37.780304] Internal error: : 1c06 [#1] ARM
[ 37.784670] Modules linked in:
[ 37.787908] CPU: 0 PID: 428 Comm: sh Not tainted 3.18.0-rc5-00119-geefd097-dirty #1540
[ 37.796142] task: 8e246c00 ti: 8ca6c000 task.ti: 8ca6c000
[ 37.801785] PC is at esdhc_writel_le+0x40/0xec
[ 37.806431] LR is at sdhci_set_card_detection+0xe0/0xe4
[ 37.811877] pc : [<803f0584>] lr : [<803eaaa0>] psr: 400f0013
[ 37.811877] sp : 8ca6dd28 ip : 00000001 fp : 8ca6dd3c
[ 37.823766] r10: 807a233c r9 : 00000000 r8 : 8e8b7210
[ 37.829194] r7 : 802d8a08 r6 : 8082e928 r5 : 00000000 r4 : 00000002
[ 37.835974] r3 : 8ea34e90 r2 : 00000038 r1 : 00000000 r0 : 8ea32ac0
...

Clocks need to be enabled to access the registers. Fix the issue by
add runtime PM enabled pltfm implementation of suspend/resume which
take care of clocks by using the runtime PM API properly.

Signed-off-by: Stefan Agner <stefan@agner.ch>
---
Changes since v2:
- Implement a generic pltfm suspend/resume function instead of a local
function in sdhci-esdhc-imx.c
- Convert sdhci-pxav3 to use the runtime PM enabled pltfm suspend/resume
function too

drivers/mmc/host/sdhci-esdhc-imx.c | 2 +-
drivers/mmc/host/sdhci-pltfm.c | 36 ++++++++++++++++++++++++++++++++++++
drivers/mmc/host/sdhci-pltfm.h | 2 ++
3 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c
index 82f512d..7b7b3a3 100644
--- a/drivers/mmc/host/sdhci-esdhc-imx.c
+++ b/drivers/mmc/host/sdhci-esdhc-imx.c
@@ -1132,7 +1132,7 @@ static int sdhci_esdhc_runtime_resume(struct device *dev)
#endif

static const struct dev_pm_ops sdhci_esdhc_pmops = {
- SET_SYSTEM_SLEEP_PM_OPS(sdhci_pltfm_suspend, sdhci_pltfm_resume)
+ SET_SYSTEM_SLEEP_PM_OPS(sdhci_pltfm_rpm_suspend, sdhci_pltfm_rpm_resume)
SET_RUNTIME_PM_OPS(sdhci_esdhc_runtime_suspend,
sdhci_esdhc_runtime_resume, NULL)
};
diff --git a/drivers/mmc/host/sdhci-pltfm.c b/drivers/mmc/host/sdhci-pltfm.c
index a207f5a..38c03cd 100644
--- a/drivers/mmc/host/sdhci-pltfm.c
+++ b/drivers/mmc/host/sdhci-pltfm.c
@@ -31,6 +31,7 @@
#include <linux/err.h>
#include <linux/module.h>
#include <linux/of.h>
+#include <linux/pm_runtime.h>
#ifdef CONFIG_PPC
#include <asm/machdep.h>
#endif
@@ -256,6 +257,41 @@ const struct dev_pm_ops sdhci_pltfm_pmops = {
.resume = sdhci_pltfm_resume,
};
EXPORT_SYMBOL_GPL(sdhci_pltfm_pmops);
+
+int sdhci_pltfm_rpm_suspend(struct device *dev)
+{
+ int ret;
+ struct sdhci_host *host = dev_get_drvdata(dev);
+
+ pm_runtime_get_sync(dev);
+ ret = sdhci_suspend_host(host);
+ pm_runtime_mark_last_busy(dev);
+ pm_runtime_put_autosuspend(dev);
+ if (ret)
+ return ret;
+
+ return pm_runtime_force_suspend(dev);
+}
+EXPORT_SYMBOL_GPL(sdhci_pltfm_rpm_suspend);
+
+int sdhci_pltfm_rpm_resume(struct device *dev)
+{
+ int ret;
+ struct sdhci_host *host = dev_get_drvdata(dev);
+
+ ret = pm_runtime_force_resume(dev);
+
+ if (ret)
+ return ret;
+
+ pm_runtime_get_sync(dev);
+ ret = sdhci_resume_host(host);
+ pm_runtime_mark_last_busy(dev);
+ pm_runtime_put_autosuspend(dev);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(sdhci_pltfm_rpm_resume);
#endif /* CONFIG_PM */

static int __init sdhci_pltfm_drv_init(void)
diff --git a/drivers/mmc/host/sdhci-pltfm.h b/drivers/mmc/host/sdhci-pltfm.h
index 04bc248..ac5f6ea 100644
--- a/drivers/mmc/host/sdhci-pltfm.h
+++ b/drivers/mmc/host/sdhci-pltfm.h
@@ -114,6 +114,8 @@ static inline void *sdhci_pltfm_priv(struct sdhci_pltfm_host *host)
extern int sdhci_pltfm_suspend(struct device *dev);
extern int sdhci_pltfm_resume(struct device *dev);
extern const struct dev_pm_ops sdhci_pltfm_pmops;
+extern int sdhci_pltfm_rpm_suspend(struct device *dev);
+extern int sdhci_pltfm_rpm_resume(struct device *dev);
#define SDHCI_PLTFM_PMOPS (&sdhci_pltfm_pmops)
#else
#define SDHCI_PLTFM_PMOPS NULL
--
2.4.1