Revert "clocksource: sh_tmu: Runtime PM support"
Paul Mundt [Tue, 31 May 2011 06:23:20 +0000 (15:23 +0900)]
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>

drivers/clocksource/sh_tmu.c

index 1729628..8081357 100644 (file)
@@ -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;
 }