From: Paul Mundt <lethal@linux-sh.org>
Date: Tue, 31 May 2011 06:23:20 +0000 (+0900)
Subject: Revert "clocksource: sh_tmu: Runtime PM support"
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=d4905ce38c73964b868037e49a5945e1cf47a7f2;p=linux-beck.git

Revert "clocksource: sh_tmu: Runtime PM support"

This reverts commit 1b842e91fea9447eff5eb687e28ad61c02f5033e.

There is a fundamental ordering race between the early and late probe
paths and the runtime PM tie-in that results in __pm_runtime_resume()
attempting to take a lock that hasn't been initialized yet (which by
proxy also suggests that pm_runtime_init() hasn't yet been run on the
device either, making the entire thing unsafe) -- resulting in instant
death on SMP or on UP with spinlock debugging enabled:

	 sh_tmu.0: used for clock events
	 sh_tmu.0: used for periodic clock events
	BUG: spinlock trylock failure on UP on CPU#0, swapper/0
	 lock: 804db198, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
	...

Revert it for now until the ordering issues can be resolved, or we can get
some more help from the runtime PM framework to make this possible.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
---

diff --git a/drivers/clocksource/sh_tmu.c b/drivers/clocksource/sh_tmu.c
index 17296288a205..808135768617 100644
--- a/drivers/clocksource/sh_tmu.c
+++ b/drivers/clocksource/sh_tmu.c
@@ -25,7 +25,6 @@
 #include <linux/delay.h>
 #include <linux/io.h>
 #include <linux/clk.h>
-#include <linux/pm_runtime.h>
 #include <linux/irq.h>
 #include <linux/err.h>
 #include <linux/clocksource.h>
@@ -110,12 +109,10 @@ static int sh_tmu_enable(struct sh_tmu_priv *p)
 {
 	int ret;
 
-	/* wake up device and enable clock */
-	pm_runtime_get_sync(&p->pdev->dev);
+	/* enable clock */
 	ret = clk_enable(p->clk);
 	if (ret) {
 		dev_err(&p->pdev->dev, "cannot enable clock\n");
-		pm_runtime_put_sync(&p->pdev->dev);
 		return ret;
 	}
 
@@ -144,9 +141,8 @@ static void sh_tmu_disable(struct sh_tmu_priv *p)
 	/* disable interrupts in TMU block */
 	sh_tmu_write(p, TCR, 0x0000);
 
-	/* stop clock and mark device as idle */
+	/* stop clock */
 	clk_disable(p->clk);
-	pm_runtime_put_sync(&p->pdev->dev);
 }
 
 static void sh_tmu_set_next(struct sh_tmu_priv *p, unsigned long delta,
@@ -415,7 +411,6 @@ static int __devinit sh_tmu_probe(struct platform_device *pdev)
 
 	if (p) {
 		dev_info(&pdev->dev, "kept as earlytimer\n");
-		pm_runtime_enable(&pdev->dev);
 		return 0;
 	}
 
@@ -430,9 +425,6 @@ static int __devinit sh_tmu_probe(struct platform_device *pdev)
 		kfree(p);
 		platform_set_drvdata(pdev, NULL);
 	}
-
-	if (!is_early_platform_device(pdev))
-		pm_runtime_enable(&pdev->dev);
 	return ret;
 }