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Commit ee894b18 authored by Artem Bityutskiy's avatar Artem Bityutskiy Committed by Kevin Hilman
Browse files

OMAP3: PM: introduce a new powerdomain walk helper 



The 'pwrdm_for_each()' function walks powerdomains with a spinlock
locked, so the the callbacks cannot do anything which may sleep.
This patch introduces a 'pwrdm_for_each_nolock()' helper which does
the same, but without the spinlock locked. This fixes the following
lockdep warning:

[    0.000000] WARNING: at kernel/lockdep.c:2460 lockdep_trace_alloc+0xac/0xec()
[    0.000000] Modules linked in:
(unwind_backtrace+0x0/0xdc) from [<c0045464>] (warn_slowpath_common+0x48/0x60)
(warn_slowpath_common+0x48/0x60) from [<c0067dd4>] (lockdep_trace_alloc+0xac/0xec)
(lockdep_trace_alloc+0xac/0xec) from [<c009da14>] (kmem_cache_alloc+0x1c/0xd0)
(kmem_cache_alloc+0x1c/0xd0) from [<c00b21d8>] (d_alloc+0x1c/0x1a4)
(d_alloc+0x1c/0x1a4) from [<c00a887c>] (__lookup_hash+0xd8/0x118)
(__lookup_hash+0xd8/0x118) from [<c00a9f20>] (lookup_one_len+0x84/0x94)
(lookup_one_len+0x84/0x94) from [<c010d12c>] (debugfs_create_file+0x8c/0x20c)
(debugfs_create_file+0x8c/0x20c) from [<c010d320>] (debugfs_create_dir+0x1c/0x20)
(debugfs_create_dir+0x1c/0x20) from [<c000e8cc>] (pwrdms_setup+0x60/0x90)
(pwrdms_setup+0x60/0x90) from [<c002e010>] (pwrdm_for_each+0x30/0x80)
(pwrdm_for_each+0x30/0x80) from [<c000e79c>] (pm_dbg_init+0x7c/0x14c)
(pm_dbg_init+0x7c/0x14c) from [<c00232b4>] (do_one_initcall+0x5c/0x1b8)
(do_one_initcall+0x5c/0x1b8) from [<c00083f8>] (kernel_init+0x90/0x10c)
(kernel_init+0x90/0x10c) from [<c00242c4>] (kernel_thread_exit+0x0/0x8)

Signed-off-by: default avatarArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: default avatarKevin Hilman <khilman@deeprootsystems.com>
parent eb350f74

arch/arm/mach-omap2/pm-debug.c

+2 −2
Original line number Diff line number Diff line
@@ -551,7 +551,7 @@ static int __init pm_dbg_init(void) 
	(void) debugfs_create_file("time", S_IRUGO,

		d, (void *)DEBUG_FILE_TIMERS, &debug_fops);



	pwrdm_for_each(pwrdms_setup, (void *)d);

	pwrdm_for_each_nolock(pwrdms_setup, (void *)d);



	pm_dbg_dir = debugfs_create_dir("registers", d);

	if (IS_ERR(pm_dbg_dir))

arch/arm/mach-omap2/powerdomain.c

+27 −12
Original line number Diff line number Diff line
@@ -273,35 +273,50 @@ struct powerdomain *pwrdm_lookup(const char *name) 
}



/**

 * pwrdm_for_each - call function on each registered clockdomain

 * pwrdm_for_each_nolock - call function on each registered clockdomain

 * @fn: callback function *

 *

 * Call the supplied function for each registered powerdomain.  The

 * callback function can return anything but 0 to bail out early from

 * the iterator.  The callback function is called with the pwrdm_rwlock

 * held for reading, so no powerdomain structure manipulation

 * functions should be called from the callback, although hardware

 * powerdomain control functions are fine.  Returns the last return

 * value of the callback function, which should be 0 for success or

 * anything else to indicate failure; or -EINVAL if the function

 * pointer is null.

 * the iterator.  Returns the last return value of the callback function, which

 * should be 0 for success or anything else to indicate failure; or -EINVAL if

 * the function pointer is null.

 */

int pwrdm_for_each(int (*fn)(struct powerdomain *pwrdm, void *user),

int pwrdm_for_each_nolock(int (*fn)(struct powerdomain *pwrdm, void *user),

				void *user)

{

	struct powerdomain *temp_pwrdm;

	unsigned long flags;

	int ret = 0;



	if (!fn)

		return -EINVAL;



	read_lock_irqsave(&pwrdm_rwlock, flags);

	list_for_each_entry(temp_pwrdm, &pwrdm_list, node) {

		ret = (*fn)(temp_pwrdm, user);

		if (ret)

			break;

	}



	return ret;

}



/**

 * pwrdm_for_each - call function on each registered clockdomain

 * @fn: callback function *

 *

 * This function is the same as 'pwrdm_for_each_nolock()', but keeps the

 * &pwrdm_rwlock locked for reading, so no powerdomain structure manipulation

 * functions should be called from the callback, although hardware powerdomain

 * control functions are fine.

 */

int pwrdm_for_each(int (*fn)(struct powerdomain *pwrdm, void *user),

			void *user)

{

	unsigned long flags;

	int ret;



	read_lock_irqsave(&pwrdm_rwlock, flags);

	ret = pwrdm_for_each_nolock(fn, user);

	read_unlock_irqrestore(&pwrdm_rwlock, flags);



	return ret;

arch/arm/plat-omap/include/mach/powerdomain.h

+2 −0
Original line number Diff line number Diff line
@@ -135,6 +135,8 @@ struct powerdomain *pwrdm_lookup(const char *name); 


int pwrdm_for_each(int (*fn)(struct powerdomain *pwrdm, void *user),

			void *user);

int pwrdm_for_each_nolock(int (*fn)(struct powerdomain *pwrdm, void *user),

			void *user);



int pwrdm_add_clkdm(struct powerdomain *pwrdm, struct clockdomain *clkdm);

int pwrdm_del_clkdm(struct powerdomain *pwrdm, struct clockdomain *clkdm);