The generic rwsem implementation of down_read() and down_write() does not
save and restore interrupt state. This causes powerdomain code to
inadvertently enable interrupts early in the boot process, causing
init/main.c to complain. This patch converts powerdomain locking to
r-w spinlocks instead.
I'm also curious to know if this fixes the BeagleBoard boot problem.
Signed-off-by: Paul Walmsley <paul@xxxxxxxxx>
---
arch/arm/mach-omap2/powerdomain.c | 46 ++++++++++++++++++++++---------------
1 files changed, 27 insertions(+), 19 deletions(-)
diff --git a/arch/arm/mach-omap2/powerdomain.c b/arch/arm/mach-omap2/powerdomain.c
index 939efe4..0a6caaf 100644
--- a/arch/arm/mach-omap2/powerdomain.c
+++ b/arch/arm/mach-omap2/powerdomain.c
@@ -18,7 +18,7 @@
#include <linux/module.h>
#include <linux/types.h>
#include <linux/delay.h>
-#include <linux/rwsem.h>
+#include <linux/spinlock.h>
#include <linux/list.h>
#include <linux/errno.h>
#include <linux/err.h>
@@ -38,10 +38,10 @@
static LIST_HEAD(pwrdm_list);
/*
- * pwrdm_rwsem protects pwrdm_list add and del ops - also reused to
+ * pwrdm_rwlock protects pwrdm_list add and del ops - also reused to
* protect pwrdm_clkdms[] during clkdm add/del ops
*/
-static DECLARE_RWSEM(pwrdm_rwsem);
+static DEFINE_RWLOCK(pwrdm_rwlock);
/* Private functions */
@@ -131,6 +131,7 @@ void pwrdm_init(struct powerdomain **pwrdm_list)
*/
int pwrdm_register(struct powerdomain *pwrdm)
{
+ unsigned long flags;
int ret = -EINVAL;
if (!pwrdm)
@@ -139,7 +140,7 @@ int pwrdm_register(struct powerdomain *pwrdm)
if (!omap_chip_is(pwrdm->omap_chip))
return -EINVAL;
- down_write(&pwrdm_rwsem);
+ write_lock_irqsave(&pwrdm_rwlock, flags);
if (_pwrdm_lookup(pwrdm->name)) {
ret = -EEXIST;
goto pr_unlock;
@@ -151,7 +152,7 @@ int pwrdm_register(struct powerdomain *pwrdm)
ret = 0;
pr_unlock:
- up_write(&pwrdm_rwsem);
+ write_unlock_irqrestore(&pwrdm_rwlock, flags);
return ret;
}
@@ -165,12 +166,14 @@ pr_unlock:
*/
int pwrdm_unregister(struct powerdomain *pwrdm)
{
+ unsigned long flags;
+
if (!pwrdm)
return -EINVAL;
- down_write(&pwrdm_rwsem);
+ write_lock_irqsave(&pwrdm_rwlock, flags);
list_del(&pwrdm->node);
- up_write(&pwrdm_rwsem);
+ write_unlock_irqrestore(&pwrdm_rwlock, flags);
pr_debug("powerdomain: unregistered %s\n", pwrdm->name);
@@ -187,13 +190,14 @@ int pwrdm_unregister(struct powerdomain *pwrdm)
struct powerdomain *pwrdm_lookup(const char *name)
{
struct powerdomain *pwrdm;
+ unsigned long flags;
if (!name)
return NULL;
- down_read(&pwrdm_rwsem);
+ read_lock_irqsave(&pwrdm_rwlock, flags);
pwrdm = _pwrdm_lookup(name);
- up_read(&pwrdm_rwsem);
+ read_unlock_irqrestore(&pwrdm_rwlock, flags);
return pwrdm;
}
@@ -204,7 +208,7 @@ struct powerdomain *pwrdm_lookup(const char *name)
*
* 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_rwsem
+ * 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
@@ -215,18 +219,19 @@ struct powerdomain *pwrdm_lookup(const char *name)
int pwrdm_for_each(int (*fn)(struct powerdomain *pwrdm))
{
struct powerdomain *temp_pwrdm;
+ unsigned long flags;
int ret = 0;
if (!fn)
return -EINVAL;
- down_read(&pwrdm_rwsem);
+ read_lock_irqsave(&pwrdm_rwlock, flags);
list_for_each_entry(temp_pwrdm, &pwrdm_list, node) {
ret = (*fn)(temp_pwrdm);
if (ret)
break;
}
- up_read(&pwrdm_rwsem);
+ read_unlock_irqrestore(&pwrdm_rwlock, flags);
return ret;
}
@@ -243,6 +248,7 @@ int pwrdm_for_each(int (*fn)(struct powerdomain *pwrdm))
*/
int pwrdm_add_clkdm(struct powerdomain *pwrdm, struct clockdomain *clkdm)
{
+ unsigned long flags;
int i;
int ret = -EINVAL;
@@ -252,7 +258,7 @@ int pwrdm_add_clkdm(struct powerdomain *pwrdm, struct clockdomain *clkdm)
pr_debug("powerdomain: associating clockdomain %s with powerdomain "
"%s\n", clkdm->name, pwrdm->name);
- down_write(&pwrdm_rwsem);
+ write_lock_irqsave(&pwrdm_rwlock, flags);
for (i = 0; i < PWRDM_MAX_CLKDMS; i++) {
if (!pwrdm->pwrdm_clkdms[i])
@@ -278,7 +284,7 @@ int pwrdm_add_clkdm(struct powerdomain *pwrdm, struct clockdomain *clkdm)
ret = 0;
pac_exit:
- up_write(&pwrdm_rwsem);
+ write_unlock_irqrestore(&pwrdm_rwlock, flags);
return ret;
}
@@ -295,6 +301,7 @@ pac_exit:
*/
int pwrdm_del_clkdm(struct powerdomain *pwrdm, struct clockdomain *clkdm)
{
+ unsigned long flags;
int ret = -EINVAL;
int i;
@@ -304,7 +311,7 @@ int pwrdm_del_clkdm(struct powerdomain *pwrdm, struct clockdomain *clkdm)
pr_debug("powerdomain: dissociating clockdomain %s from powerdomain "
"%s\n", clkdm->name, pwrdm->name);
- down_write(&pwrdm_rwsem);
+ write_lock_irqsave(&pwrdm_rwlock, flags);
for (i = 0; i < PWRDM_MAX_CLKDMS; i++)
if (pwrdm->pwrdm_clkdms[i] == clkdm)
@@ -322,7 +329,7 @@ int pwrdm_del_clkdm(struct powerdomain *pwrdm, struct clockdomain *clkdm)
ret = 0;
pdc_exit:
- up_write(&pwrdm_rwsem);
+ write_unlock_irqrestore(&pwrdm_rwlock, flags);
return ret;
}
@@ -335,7 +342,7 @@ pdc_exit:
* Call the supplied function for each clockdomain in the powerdomain
* 'pwrdm'. The callback function can return anything but 0 to bail
* out early from the iterator. The callback function is called with
- * the pwrdm_rwsem held for reading, so no powerdomain structure
+ * 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 -EINVAL
* if presented with invalid pointers; or passes along the last return
@@ -346,18 +353,19 @@ int pwrdm_for_each_clkdm(struct powerdomain *pwrdm,
int (*fn)(struct powerdomain *pwrdm,
struct clockdomain *clkdm))
{
+ unsigned long flags;
int ret = 0;
int i;
if (!fn)
return -EINVAL;
- down_read(&pwrdm_rwsem);
+ read_lock_irqsave(&pwrdm_rwlock, flags);
for (i = 0; i < PWRDM_MAX_CLKDMS && !ret; i++)
ret = (*fn)(pwrdm, pwrdm->pwrdm_clkdms[i]);
- up_read(&pwrdm_rwsem);
+ read_unlock_irqrestore(&pwrdm_rwlock, flags);
return ret;
}
--
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