[PATCH] drivers/rtc/rtc-sirfsoc.c: fix kernel panic of backing from hibernation

From: Xianglong Du <redacted>

RTC settings will be lost if power supply is cut off after hibernation finished,
but the current "restore" function does not restore RTC related settings, this
causes rtc_read_time failure and kernel panic:
[   72.873363] rtc rtc0: **** DPM device timeout ****
[   72.875332] [<c00154e4>] (unwind_backtrace+0x0/0xf4) from [<c00120b4>] (show_stack+0x10/0x14)
[   72.883862] [<c00120b4>] (show_stack+0x10/0x14) from [<c02179b4>] (dpm_wd_handler+0x24/0x28)
[   72.892288] [<c02179b4>] (dpm_wd_handler+0x24/0x28) from [<c002d6f0>] (call_timer_fn.isra.33+0x24/0x88)
[   72.901663] [<c002d6f0>] (call_timer_fn.isra.33+0x24/0x88) from [<c002d8cc>] (run_timer_softirq+0x178/0x1f0)
[   72.911463] [<c002d8cc>] (run_timer_softirq+0x178/0x1f0) from [<c0027c8c>] (__do_softirq+0x120/0x200)
[   72.920658] [<c0027c8c>] (__do_softirq+0x120/0x200) from [<c0027e1c>] (do_softirq+0x54/0x5c)
[   72.929075] [<c0027e1c>] (do_softirq+0x54/0x5c) from [<c00280c4>] (irq_exit+0x9c/0xd0)
[   72.936971] [<c00280c4>] (irq_exit+0x9c/0xd0) from [<c000ef84>] (handle_IRQ+0x44/0x90)
[   72.944876] [<c000ef84>] (handle_IRQ+0x44/0x90) from [<c000dc80>] (__irq_svc+0x40/0x70)
[   72.952841] [<c000dc80>] (__irq_svc+0x40/0x70) from [<c03864b4>] (_raw_spin_unlock_irqrestore+0x10/0x48)
[   72.962325] [<c03864b4>] (_raw_spin_unlock_irqrestore+0x10/0x48) from [<c001ddc0>] (sirfsoc_rtc_iobrg_readl+0x34/0x3c)
[   72.973007] [<c001ddc0>] (sirfsoc_rtc_iobrg_readl+0x34/0x3c) from [<c027caf8>] (sirfsoc_rtc_read_time+0x24/0x48)
[   72.983147] [<c027caf8>] (sirfsoc_rtc_read_time+0x24/0x48) from [<c027a930>] (__rtc_read_time.isra.3+0x48/0x5c)
[   72.993229] [<c027a930>] (__rtc_read_time.isra.3+0x48/0x5c) from [<c027a974>] (rtc_read_time+0x30/0x44)
[   73.002592] [<c027a974>] (rtc_read_time+0x30/0x44) from [<c027a2f0>] (rtc_resume.part.9+0x20/0x104)
[   73.011620] [<c027a2f0>] (rtc_resume.part.9+0x20/0x104) from [<c027a430>] (rtc_resume+0x5c/0x64)
[   73.020388] [<c027a430>] (rtc_resume+0x5c/0x64) from [<c0217a4c>] (dpm_run_callback.isra.4+0x2c/0x74)
[   73.029597] [<c0217a4c>] (dpm_run_callback.isra.4+0x2c/0x74) from [<c0217f80>] (device_resume+0x9c/0x144)
[   73.039134] [<c0217f80>] (device_resume+0x9c/0x144) from [<c0218aec>] (dpm_resume+0x100/0x224)
[   73.047734] [<c0218aec>] (dpm_resume+0x100/0x224) from [<c0056f4c>] (hibernation_snapshot+0x170/0x398)
[   73.057019] [<c0056f4c>] (hibernation_snapshot+0x170/0x398) from [<c00575b4>] (hibernate+0x13c/0x1d8)
[   73.066212] [<c00575b4>] (hibernate+0x13c/0x1d8) from [<c00556f4>] (state_store+0xb4/0xb8)
[   73.074474] [<c00556f4>] (state_store+0xb4/0xb8) from [<c0197d50>] (kobj_attr_store+0x14/0x20)
[   73.083033] [<c0197d50>] (kobj_attr_store+0x14/0x20) from [<c0118c04>] (sysfs_write_file+0x160/0x190)
[   73.092271] [<c0118c04>] (sysfs_write_file+0x160/0x190) from [<c00c2b08>] (vfs_write+0xb4/0x194)
[   73.101027] [<c00c2b08>] (vfs_write+0xb4/0x194) from [<c00c3088>] (SyS_write+0x3c/0x78)
[   73.109016] [<c00c3088>] (SyS_write+0x3c/0x78) from [<c000e080>] (ret_fast_syscall+0x0/0x30)

this patch uses SIMPLE_DEV_PM_OPS() to make restore() execute the existing resume()
function which will restore the set of RTC.

Signed-off-by: Xianglong Du <redacted>
Signed-off-by: Barry Song <redacted>
---
 drivers/rtc/rtc-sirfsoc.c |   62 ++++++--------------------------------------
 1 files changed, 9 insertions(+), 53 deletions(-)

diff --git a/drivers/rtc/rtc-sirfsoc.c b/drivers/rtc/rtc-sirfsoc.c
index 3eb3642..14f6179 100644
--- a/drivers/rtc/rtc-sirfsoc.c
+++ b/drivers/rtc/rtc-sirfsoc.c

@@ -335,39 +335,29 @@ static int sirfsoc_rtc_remove(struct platform_device *pdev)
 	return 0;
 }
 
-#ifdef CONFIG_PM
-
+#ifdef CONFIG_PM_SLEEP
 static int sirfsoc_rtc_suspend(struct device *dev)
 {
-	struct platform_device *pdev = to_platform_device(dev);
-	struct sirfsoc_rtc_drv *rtcdrv = platform_get_drvdata(pdev);
+	struct sirfsoc_rtc_drv *rtcdrv = dev_get_drvdata(dev);
 	rtcdrv->overflow_rtc =
 		sirfsoc_rtc_iobrg_readl(rtcdrv->rtc_base + RTC_SW_VALUE);
 
 	rtcdrv->saved_counter =
 		sirfsoc_rtc_iobrg_readl(rtcdrv->rtc_base + RTC_CN);
 	rtcdrv->saved_overflow_rtc = rtcdrv->overflow_rtc;
-	if (device_may_wakeup(&pdev->dev) && !enable_irq_wake(rtcdrv->irq))
+	if (device_may_wakeup(dev) && !enable_irq_wake(rtcdrv->irq))
 		rtcdrv->irq_wake = 1;
 
 	return 0;
 }
 
-static int sirfsoc_rtc_freeze(struct device *dev)
-{
-	sirfsoc_rtc_suspend(dev);
-
-	return 0;
-}
-
-static int sirfsoc_rtc_thaw(struct device *dev)
+static int sirfsoc_rtc_resume(struct device *dev)
 {
 	u32 tmp;
-	struct sirfsoc_rtc_drv *rtcdrv;
-	rtcdrv = dev_get_drvdata(dev);
+	struct sirfsoc_rtc_drv *rtcdrv = dev_get_drvdata(dev);
 
 	/*
-	 * if resume from snapshot and the rtc power is losed,
+	 * if resume from snapshot and the rtc power is lost,
 	 * restroe the rtc settings
 	 */
 	if (SIRFSOC_RTC_CLK != sirfsoc_rtc_iobrg_readl(

@@ -407,57 +397,23 @@ static int sirfsoc_rtc_thaw(struct device *dev)
 	sirfsoc_rtc_iobrg_writel(rtcdrv->overflow_rtc,
 			rtcdrv->rtc_base + RTC_SW_VALUE);
 
-	return 0;
-}
-
-static int sirfsoc_rtc_resume(struct device *dev)
-{
-	struct platform_device *pdev = to_platform_device(dev);
-	struct sirfsoc_rtc_drv *rtcdrv = platform_get_drvdata(pdev);
-	sirfsoc_rtc_thaw(dev);
-	if (device_may_wakeup(&pdev->dev) && rtcdrv->irq_wake) {
+	if (device_may_wakeup(dev) && rtcdrv->irq_wake) {
 		disable_irq_wake(rtcdrv->irq);
 		rtcdrv->irq_wake = 0;
 	}
 
 	return 0;
 }
-
-static int sirfsoc_rtc_restore(struct device *dev)
-{
-	struct platform_device *pdev = to_platform_device(dev);
-	struct sirfsoc_rtc_drv *rtcdrv = platform_get_drvdata(pdev);
-
-	if (device_may_wakeup(&pdev->dev) && rtcdrv->irq_wake) {
-		disable_irq_wake(rtcdrv->irq);
-		rtcdrv->irq_wake = 0;
-	}
-	return 0;
-}
-
-#else
-#define sirfsoc_rtc_suspend	NULL
-#define sirfsoc_rtc_resume	NULL
-#define sirfsoc_rtc_freeze	NULL
-#define sirfsoc_rtc_thaw	NULL
-#define sirfsoc_rtc_restore	NULL
 #endif
 
-static const struct dev_pm_ops sirfsoc_rtc_pm_ops = {
-	.suspend = sirfsoc_rtc_suspend,
-	.resume = sirfsoc_rtc_resume,
-	.freeze = sirfsoc_rtc_freeze,
-	.thaw = sirfsoc_rtc_thaw,
-	.restore = sirfsoc_rtc_restore,
-};
+static SIMPLE_DEV_PM_OPS(sirfsoc_rtc_pm_ops,
+		sirfsoc_rtc_suspend, sirfsoc_rtc_resume);
 
 static struct platform_driver sirfsoc_rtc_driver = {
 	.driver = {
 		.name = "sirfsoc-rtc",
 		.owner = THIS_MODULE,
-#ifdef CONFIG_PM
 		.pm = &sirfsoc_rtc_pm_ops,
-#endif
 		.of_match_table = sirfsoc_rtc_of_match,
 	},
 	.probe = sirfsoc_rtc_probe,

-- 
1.7.5.4