On Wed, 11 Aug 2010, Kevin Hilman wrote:
> From: Kevin Hilman <khilman@xxxxxx>
>
> Currently omap_hwmod_mutex is being used to protect both the list
> access/modification and concurrent access to hwmod functions. This
> patch separates these two types of locking.
>
> First, omap_hwmod_mutex is used only to protect access and
> modification of omap_hwmod_list. Also cleaned up some comments
> referring to this mutex that are no longer needed.
>
> Then, for protecting concurrent access to hwmod functions, use a
> per-hwmod mutex. This protects concurrent access to a single hwmod,
> but would allow concurrent access to different hwmods.
>
> Signed-off-by: Kevin Hilman <khilman@xxxxxxxxxxxxxxxxxxx>
I've added some structure kerneldoc for the new field, prefixed its name
with an underscore (to indicate that it is an internal structure field
that should not be externally initialized or touched), fixed a whitespace
problem, and queued this patch for 2.6.36 in my 'hwmod_2.6.36' branch.
Updated patch below.
Thanks Kevin,
- Paul
>From b6394ba8ff2ffcd1a6dd0e680d29c5ce9f850dd5 Mon Sep 17 00:00:00 2001
From: Kevin Hilman <khilman@xxxxxx>
Date: Wed, 1 Sep 2010 11:07:11 -0600
Subject: [PATCH] [PATCH] OMAP: hwmod: separate list locking and hwmod hardware locking
Currently omap_hwmod_mutex is being used to protect both the list
access/modification and concurrent access to hwmod functions. This
patch separates these two types of locking.
First, omap_hwmod_mutex is used only to protect access and
modification of omap_hwmod_list. Also cleaned up some comments
referring to this mutex that are no longer needed.
Then, for protecting concurrent access to hwmod functions, use a
per-hwmod mutex. This protects concurrent access to a single hwmod,
but would allow concurrent access to different hwmods.
Signed-off-by: Kevin Hilman <khilman@xxxxxxxxxxxxxxxxxxx>
[paul@xxxxxxxxx: added structure documentation; changed mutex variable
name]
Signed-off-by: Paul Walmsley <paul@xxxxxxxxx>
---
arch/arm/mach-omap2/omap_hwmod.c | 62 ++++++++++++-------------
arch/arm/plat-omap/include/plat/omap_hwmod.h | 3 +
2 files changed, 33 insertions(+), 32 deletions(-)
diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
index 5bb25e3..6676fdd 100644
--- a/arch/arm/mach-omap2/omap_hwmod.c
+++ b/arch/arm/mach-omap2/omap_hwmod.c
@@ -767,10 +767,10 @@ static struct omap_hwmod *_lookup(const char *name)
* @data: not used; pass NULL
*
* Called by omap_hwmod_late_init() (after omap2_clk_init()).
- * Resolves all clock names embedded in the hwmod. Must be called
- * with omap_hwmod_mutex held. Returns -EINVAL if the omap_hwmod
- * has not yet been registered or if the clocks have already been
- * initialized, 0 on success, or a non-zero error on failure.
+ * Resolves all clock names embedded in the hwmod. Returns -EINVAL if
+ * the omap_hwmod has not yet been registered or if the clocks have
+ * already been initialized, 0 on success, or a non-zero error on
+ * failure.
*/
static int _init_clocks(struct omap_hwmod *oh, void *data)
{
@@ -838,10 +838,9 @@ static int _wait_target_ready(struct omap_hwmod *oh)
* @oh: struct omap_hwmod *
*
* Resets an omap_hwmod @oh via the OCP_SYSCONFIG bit. hwmod must be
- * enabled for this to work. Must be called with omap_hwmod_mutex
- * held. Returns -EINVAL if the hwmod cannot be reset this way or if
- * the hwmod is in the wrong state, -ETIMEDOUT if the module did not
- * reset in time, or 0 upon success.
+ * enabled for this to work. Returns -EINVAL if the hwmod cannot be
+ * reset this way or if the hwmod is in the wrong state, -ETIMEDOUT if
+ * the module did not reset in time, or 0 upon success.
*/
static int _reset(struct omap_hwmod *oh)
{
@@ -891,9 +890,8 @@ static int _reset(struct omap_hwmod *oh)
* @oh: struct omap_hwmod *
*
* Enables an omap_hwmod @oh such that the MPU can access the hwmod's
- * register target. Must be called with omap_hwmod_mutex held.
- * Returns -EINVAL if the hwmod is in the wrong state or passes along
- * the return value of _wait_target_ready().
+ * register target. Returns -EINVAL if the hwmod is in the wrong
+ * state or passes along the return value of _wait_target_ready().
*/
int _omap_hwmod_enable(struct omap_hwmod *oh)
{
@@ -1004,11 +1002,10 @@ static int _shutdown(struct omap_hwmod *oh)
* @skip_setup_idle_p: do not idle hwmods at the end of the fn if 1
*
* Writes the CLOCKACTIVITY bits @clockact to the hwmod @oh
- * OCP_SYSCONFIG register. Must be called with omap_hwmod_mutex held.
- * @skip_setup_idle is intended to be used on a system that will not
- * call omap_hwmod_enable() to enable devices (e.g., a system without
- * PM runtime). Returns -EINVAL if the hwmod is in the wrong state or
- * returns 0.
+ * OCP_SYSCONFIG register. @skip_setup_idle is intended to be used on
+ * a system that will not call omap_hwmod_enable() to enable devices
+ * (e.g., a system without PM runtime). Returns -EINVAL if the hwmod
+ * is in the wrong state or returns 0.
*/
static int _setup(struct omap_hwmod *oh, void *data)
{
@@ -1038,6 +1035,7 @@ static int _setup(struct omap_hwmod *oh, void *data)
}
}
+ mutex_init(&oh->_mutex);
oh->_state = _HWMOD_STATE_INITIALIZED;
r = _omap_hwmod_enable(oh);
@@ -1323,9 +1321,9 @@ int omap_hwmod_enable(struct omap_hwmod *oh)
if (!oh)
return -EINVAL;
- mutex_lock(&omap_hwmod_mutex);
+ mutex_lock(&oh->_mutex);
r = _omap_hwmod_enable(oh);
- mutex_unlock(&omap_hwmod_mutex);
+ mutex_unlock(&oh->_mutex);
return r;
}
@@ -1343,9 +1341,9 @@ int omap_hwmod_idle(struct omap_hwmod *oh)
if (!oh)
return -EINVAL;
- mutex_lock(&omap_hwmod_mutex);
+ mutex_lock(&oh->_mutex);
_omap_hwmod_idle(oh);
- mutex_unlock(&omap_hwmod_mutex);
+ mutex_unlock(&oh->_mutex);
return 0;
}
@@ -1363,9 +1361,9 @@ int omap_hwmod_shutdown(struct omap_hwmod *oh)
if (!oh)
return -EINVAL;
- mutex_lock(&omap_hwmod_mutex);
+ mutex_lock(&oh->_mutex);
_shutdown(oh);
- mutex_unlock(&omap_hwmod_mutex);
+ mutex_unlock(&oh->_mutex);
return 0;
}
@@ -1378,9 +1376,9 @@ int omap_hwmod_shutdown(struct omap_hwmod *oh)
*/
int omap_hwmod_enable_clocks(struct omap_hwmod *oh)
{
- mutex_lock(&omap_hwmod_mutex);
+ mutex_lock(&oh->_mutex);
_enable_clocks(oh);
- mutex_unlock(&omap_hwmod_mutex);
+ mutex_unlock(&oh->_mutex);
return 0;
}
@@ -1393,9 +1391,9 @@ int omap_hwmod_enable_clocks(struct omap_hwmod *oh)
*/
int omap_hwmod_disable_clocks(struct omap_hwmod *oh)
{
- mutex_lock(&omap_hwmod_mutex);
+ mutex_lock(&oh->_mutex);
_disable_clocks(oh);
- mutex_unlock(&omap_hwmod_mutex);
+ mutex_unlock(&oh->_mutex);
return 0;
}
@@ -1443,11 +1441,11 @@ int omap_hwmod_reset(struct omap_hwmod *oh)
if (!oh || !(oh->_state & _HWMOD_STATE_ENABLED))
return -EINVAL;
- mutex_lock(&omap_hwmod_mutex);
+ mutex_lock(&oh->_mutex);
r = _reset(oh);
if (!r)
r = _omap_hwmod_enable(oh);
- mutex_unlock(&omap_hwmod_mutex);
+ mutex_unlock(&oh->_mutex);
return r;
}
@@ -1648,9 +1646,9 @@ int omap_hwmod_enable_wakeup(struct omap_hwmod *oh)
!(oh->class->sysc->sysc_flags & SYSC_HAS_ENAWAKEUP))
return -EINVAL;
- mutex_lock(&omap_hwmod_mutex);
+ mutex_lock(&oh->_mutex);
_enable_wakeup(oh);
- mutex_unlock(&omap_hwmod_mutex);
+ mutex_unlock(&oh->_mutex);
return 0;
}
@@ -1673,9 +1671,9 @@ int omap_hwmod_disable_wakeup(struct omap_hwmod *oh)
!(oh->class->sysc->sysc_flags & SYSC_HAS_ENAWAKEUP))
return -EINVAL;
- mutex_lock(&omap_hwmod_mutex);
+ mutex_lock(&oh->_mutex);
_disable_wakeup(oh);
- mutex_unlock(&omap_hwmod_mutex);
+ mutex_unlock(&oh->_mutex);
return 0;
}
diff --git a/arch/arm/plat-omap/include/plat/omap_hwmod.h b/arch/arm/plat-omap/include/plat/omap_hwmod.h
index 5506d80..03350ba 100644
--- a/arch/arm/plat-omap/include/plat/omap_hwmod.h
+++ b/arch/arm/plat-omap/include/plat/omap_hwmod.h
@@ -35,6 +35,7 @@
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/ioport.h>
+#include <linux/mutex.h>
#include <plat/cpu.h>
struct omap_device;
@@ -433,6 +434,7 @@ struct omap_hwmod_class {
* @_state: internal-use hwmod state
* @flags: hwmod flags (documented below)
* @omap_chip: OMAP chips this hwmod is present on
+ * @_mutex: mutex serializing operations on this hwmod
* @node: list node for hwmod list (internal use)
*
* @main_clk refers to this module's "main clock," which for our
@@ -461,6 +463,7 @@ struct omap_hwmod {
void *dev_attr;
u32 _sysc_cache;
void __iomem *_mpu_rt_va;
+ struct mutex _mutex;
struct list_head node;
u16 flags;
u8 _mpu_port_index;
--
1.7.1
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