[PATCH 13/22] msm: clock: Push down clock count and locking into sub drivers

Stephen Boyd
2010-12-17T00:52:49Z

The clock voting code will need to call clk_set_rate() from
within a spinlock so we must push down the refcount and lock into
each sub driver to avoid recursive locking.

Reviewed-by: Saravana Kannan <skannan@codeaurora.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
---
arch/arm/mach-msm/clock-local.c | 3 +-
arch/arm/mach-msm/clock-pcom.c | 59 ++++++++++++++++++++++++++++++++++----
arch/arm/mach-msm/clock.c | 32 ++------------------
arch/arm/mach-msm/clock.h | 1 -
4 files changed, 58 insertions(+), 37 deletions(-)

diff --git a/arch/arm/mach-msm/clock-local.c b/arch/arm/mach-msm/clock-local.c
index f80efa6..86b5a9d 100644
--- a/arch/arm/mach-msm/clock-local.c
+++ b/arch/arm/mach-msm/clock-local.c
@@ -501,7 +501,8 @@ void local_clk_auto_off(unsigned id)
return;

spin_lock_irqsave(&local_clock_reg_lock, flags);
- local_clk_disable_reg(id);
+ if (clk->count == 0)
+ local_clk_disable_reg(id);
spin_unlock_irqrestore(&local_clock_reg_lock, flags);
}

diff --git a/arch/arm/mach-msm/clock-pcom.c b/arch/arm/mach-msm/clock-pcom.c
index 2f9d0d4..358e065 100644
--- a/arch/arm/mach-msm/clock-pcom.c
+++ b/arch/arm/mach-msm/clock-pcom.c
@@ -16,27 +16,72 @@
#include <linux/err.h>
#include <linux/ctype.h>
#include <linux/stddef.h>
+#include <linux/spinlock.h>
+
#include <mach/clk.h>

#include "proc_comm.h"
#include "clock.h"
#include "clock-pcom.h"

+struct clk_pcom {
+ unsigned count;
+};
+
+static struct clk_pcom pcom_clocks[P_NR_CLKS];
+
+static DEFINE_SPINLOCK(pc_clk_lock);
+
/*
* glue for the proc_comm interface
*/
int pc_clk_enable(unsigned id)
{
- int rc = msm_proc_comm(PCOM_CLKCTL_RPC_ENABLE, &id, NULL);
- if (rc < 0)
- return rc;
- else
- return (int)id < 0 ? -EINVAL : 0;
+ int rc;
+ unsigned long flags;
+ struct clk_pcom *clk = &pcom_clocks[id];
+
+ spin_lock_irqsave(&pc_clk_lock, flags);
+ if (clk->count == 0) {
+ rc = msm_proc_comm(PCOM_CLKCTL_RPC_ENABLE, &id, NULL);
+ if (rc < 0)
+ goto unlock;
+ else if ((int)id < 0) {
+ rc = -EINVAL;
+ goto unlock;
+ } else
+ rc = 0;
+ }
+ clk->count++;
+unlock:
+ spin_unlock_irqrestore(&pc_clk_lock, flags);
+ return rc;
}

void pc_clk_disable(unsigned id)
{
- msm_proc_comm(PCOM_CLKCTL_RPC_DISABLE, &id, NULL);
+ unsigned long flags;
+ struct clk_pcom *clk = &pcom_clocks[id];
+
+ spin_lock_irqsave(&pc_clk_lock, flags);
+ if (WARN_ON(clk->count == 0))
+ goto out;
+ clk->count--;
+ if (clk->count == 0)
+ msm_proc_comm(PCOM_CLKCTL_RPC_DISABLE, &id, NULL);
+out:
+ spin_unlock_irqrestore(&pc_clk_lock, flags);
+}
+
+void pc_clk_auto_off(unsigned id)
+{
+ unsigned long flags;
+ struct clk_pcom *clk = &pcom_clocks[id];
+
+ spin_lock_irqsave(&pc_clk_lock, flags);
+ if (clk->count == 0)
+ msm_proc_comm(PCOM_CLKCTL_RPC_DISABLE, &id, NULL);
+ spin_unlock_irqrestore(&pc_clk_lock, flags);
}

int pc_clk_reset(unsigned id, enum clk_reset_action action)
@@ -131,7 +176,7 @@ static bool pc_clk_is_local(unsigned id)
struct clk_ops clk_ops_pcom = {
.enable = pc_clk_enable,
.disable = pc_clk_disable,
- .auto_off = pc_clk_disable,
+ .auto_off = pc_clk_auto_off,
.reset = pc_clk_reset,
.set_rate = pc_clk_set_rate,
.set_min_rate = pc_clk_set_min_rate,
diff --git a/arch/arm/mach-msm/clock.c b/arch/arm/mach-msm/clock.c
index 06cd313..80e1d64 100644
--- a/arch/arm/mach-msm/clock.c
+++ b/arch/arm/mach-msm/clock.c
@@ -23,7 +23,6 @@
#include "clock.h"

static DEFINE_MUTEX(clocks_mutex);
-static DEFINE_SPINLOCK(clocks_lock);
static LIST_HEAD(clocks);

/*
@@ -57,25 +56,13 @@ EXPORT_SYMBOL(clk_put);

int clk_enable(struct clk *clk)
{
- unsigned long flags;
- spin_lock_irqsave(&clocks_lock, flags);
- clk->count++;
- if (clk->count == 1)
- clk->ops->enable(clk->id);
- spin_unlock_irqrestore(&clocks_lock, flags);
- return 0;
+ return clk->ops->enable(clk->id);
}
EXPORT_SYMBOL(clk_enable);

void clk_disable(struct clk *clk)
{
- unsigned long flags;
- spin_lock_irqsave(&clocks_lock, flags);
- BUG_ON(clk->count == 0);
- clk->count--;
- if (clk->count == 0)
- clk->ops->disable(clk->id);
- spin_unlock_irqrestore(&clocks_lock, flags);
+ clk->ops->disable(clk->id);
}
EXPORT_SYMBOL(clk_disable);

@@ -182,27 +169,16 @@ void __init msm_clock_init(struct clk *clock_tbl, unsigned num_clocks)
*/
static int __init clock_late_init(void)
{
- unsigned long flags;
struct clk *clk;
- unsigned count = 0;

clock_debug_init();
mutex_lock(&clocks_mutex);
list_for_each_entry(clk, &clocks, list) {
clock_debug_add(clk);
- if (clk->flags & CLKFLAG_AUTO_OFF) {
- spin_lock_irqsave(&clocks_lock, flags);
- if (!clk->count) {
- count++;
- clk->ops->auto_off(clk->id);
- }
- spin_unlock_irqrestore(&clocks_lock, flags);
- }
+ if (clk->flags & CLKFLAG_AUTO_OFF)
+ clk->ops->auto_off(clk->id);
}
mutex_unlock(&clocks_mutex);
- pr_info("clock_late_init() disabled %d unused clocks\n", count);
return 0;
}
-
late_initcall(clock_late_init);
-
diff --git a/arch/arm/mach-msm/clock.h b/arch/arm/mach-msm/clock.h
index 67f9d9e..4dc8853 100644
--- a/arch/arm/mach-msm/clock.h
+++ b/arch/arm/mach-msm/clock.h
@@ -51,7 +51,6 @@ struct clk_ops {
struct clk {
uint32_t id;
uint32_t remote_id;
- uint32_t count;
uint32_t flags;
const char *name;
struct clk_ops *ops;