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OMAP2+: clockdomain: Add per clkdm lock to prevent concurrent state p…
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…rogramming

Since the clkdm state programming is now done from within the hwmod
framework (which uses a per-hwmod lock) instead of the being done
from the clock framework (which used a global lock), there is now a
need to have per-clkdm locking to prevent races between different
hwmods/modules belonging to the same clock domain concurrently
programming the clkdm state.

Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Benoit Cousson <b-cousson@ti.com>
Cc: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>
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Rajendra Nayak authored and Paul Walmsley committed Jul 10, 2011
1 parent b86cfb5 commit 555e74e
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Showing 4 changed files with 50 additions and 18 deletions.
47 changes: 40 additions & 7 deletions arch/arm/mach-omap2/clockdomain.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -92,6 +92,8 @@ static int _clkdm_register(struct clockdomain *clkdm)

pwrdm_add_clkdm(pwrdm, clkdm);

spin_lock_init(&clkdm->lock);

pr_debug("clockdomain: registered %s\n", clkdm->name);

return 0;
Expand Down Expand Up @@ -690,6 +692,9 @@ int clkdm_clear_all_sleepdeps(struct clockdomain *clkdm)
*/
int clkdm_sleep(struct clockdomain *clkdm)
{
int ret;
unsigned long flags;

if (!clkdm)
return -EINVAL;

Expand All @@ -704,9 +709,11 @@ int clkdm_sleep(struct clockdomain *clkdm)

pr_debug("clockdomain: forcing sleep on %s\n", clkdm->name);

spin_lock_irqsave(&clkdm->lock, flags);
clkdm->_flags &= ~_CLKDM_FLAG_HWSUP_ENABLED;

return arch_clkdm->clkdm_sleep(clkdm);
ret = arch_clkdm->clkdm_sleep(clkdm);
spin_unlock_irqrestore(&clkdm->lock, flags);
return ret;
}

/**
Expand All @@ -720,6 +727,9 @@ int clkdm_sleep(struct clockdomain *clkdm)
*/
int clkdm_wakeup(struct clockdomain *clkdm)
{
int ret;
unsigned long flags;

if (!clkdm)
return -EINVAL;

Expand All @@ -734,9 +744,11 @@ int clkdm_wakeup(struct clockdomain *clkdm)

pr_debug("clockdomain: forcing wakeup on %s\n", clkdm->name);

spin_lock_irqsave(&clkdm->lock, flags);
clkdm->_flags &= ~_CLKDM_FLAG_HWSUP_ENABLED;

return arch_clkdm->clkdm_wakeup(clkdm);
ret = arch_clkdm->clkdm_wakeup(clkdm);
spin_unlock_irqrestore(&clkdm->lock, flags);
return ret;
}

/**
Expand All @@ -751,6 +763,8 @@ int clkdm_wakeup(struct clockdomain *clkdm)
*/
void clkdm_allow_idle(struct clockdomain *clkdm)
{
unsigned long flags;

if (!clkdm)
return;

Expand All @@ -766,10 +780,11 @@ void clkdm_allow_idle(struct clockdomain *clkdm)
pr_debug("clockdomain: enabling automatic idle transitions for %s\n",
clkdm->name);

spin_lock_irqsave(&clkdm->lock, flags);
clkdm->_flags |= _CLKDM_FLAG_HWSUP_ENABLED;

arch_clkdm->clkdm_allow_idle(clkdm);
pwrdm_clkdm_state_switch(clkdm);
spin_unlock_irqrestore(&clkdm->lock, flags);
}

/**
Expand All @@ -783,6 +798,8 @@ void clkdm_allow_idle(struct clockdomain *clkdm)
*/
void clkdm_deny_idle(struct clockdomain *clkdm)
{
unsigned long flags;

if (!clkdm)
return;

Expand All @@ -798,9 +815,10 @@ void clkdm_deny_idle(struct clockdomain *clkdm)
pr_debug("clockdomain: disabling automatic idle transitions for %s\n",
clkdm->name);

spin_lock_irqsave(&clkdm->lock, flags);
clkdm->_flags &= ~_CLKDM_FLAG_HWSUP_ENABLED;

arch_clkdm->clkdm_deny_idle(clkdm);
spin_unlock_irqrestore(&clkdm->lock, flags);
}

/**
Expand All @@ -816,16 +834,25 @@ void clkdm_deny_idle(struct clockdomain *clkdm)
*/
bool clkdm_in_hwsup(struct clockdomain *clkdm)
{
bool ret;
unsigned long flags;

if (!clkdm)
return false;

return (clkdm->_flags & _CLKDM_FLAG_HWSUP_ENABLED) ? true : false;
spin_lock_irqsave(&clkdm->lock, flags);
ret = (clkdm->_flags & _CLKDM_FLAG_HWSUP_ENABLED) ? true : false;
spin_unlock_irqrestore(&clkdm->lock, flags);

return ret;
}

/* Clockdomain-to-clock/hwmod framework interface code */

static int _clkdm_clk_hwmod_enable(struct clockdomain *clkdm)
{
unsigned long flags;

if (!clkdm || !arch_clkdm || !arch_clkdm->clkdm_clk_enable)
return -EINVAL;

Expand All @@ -837,9 +864,11 @@ static int _clkdm_clk_hwmod_enable(struct clockdomain *clkdm)
if ((atomic_inc_return(&clkdm->usecount) > 1) && autodeps)
return 0;

spin_lock_irqsave(&clkdm->lock, flags);
arch_clkdm->clkdm_clk_enable(clkdm);
pwrdm_wait_transition(clkdm->pwrdm.ptr);
pwrdm_clkdm_state_switch(clkdm);
spin_unlock_irqrestore(&clkdm->lock, flags);

pr_debug("clockdomain: clkdm %s: enabled\n", clkdm->name);

Expand All @@ -848,6 +877,8 @@ static int _clkdm_clk_hwmod_enable(struct clockdomain *clkdm)

static int _clkdm_clk_hwmod_disable(struct clockdomain *clkdm)
{
unsigned long flags;

if (!clkdm || !arch_clkdm || !arch_clkdm->clkdm_clk_disable)
return -EINVAL;

Expand All @@ -859,8 +890,10 @@ static int _clkdm_clk_hwmod_disable(struct clockdomain *clkdm)
if (atomic_dec_return(&clkdm->usecount) > 0)
return 0;

spin_lock_irqsave(&clkdm->lock, flags);
arch_clkdm->clkdm_clk_disable(clkdm);
pwrdm_clkdm_state_switch(clkdm);
spin_unlock_irqrestore(&clkdm->lock, flags);

pr_debug("clockdomain: clkdm %s: disabled\n", clkdm->name);

Expand Down
2 changes: 2 additions & 0 deletions arch/arm/mach-omap2/clockdomain.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -17,6 +17,7 @@
#define __ARCH_ARM_MACH_OMAP2_CLOCKDOMAIN_H

#include <linux/init.h>
#include <linux/spinlock.h>

#include "powerdomain.h"
#include <plat/clock.h>
Expand Down Expand Up @@ -128,6 +129,7 @@ struct clockdomain {
const struct omap_chip_id omap_chip;
atomic_t usecount;
struct list_head node;
spinlock_t lock;
};

/**
Expand Down
6 changes: 4 additions & 2 deletions arch/arm/mach-omap2/clockdomain2xxx_3xxx.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -183,7 +183,8 @@ static int omap2_clkdm_clk_enable(struct clockdomain *clkdm)
_clkdm_add_autodeps(clkdm);
_enable_hwsup(clkdm);
} else {
clkdm_wakeup(clkdm);
if (clkdm->flags & CLKDM_CAN_FORCE_WAKEUP)
omap2_clkdm_wakeup(clkdm);
}

return 0;
Expand All @@ -205,7 +206,8 @@ static int omap2_clkdm_clk_disable(struct clockdomain *clkdm)
_clkdm_del_autodeps(clkdm);
_enable_hwsup(clkdm);
} else {
clkdm_sleep(clkdm);
if (clkdm->flags & CLKDM_CAN_FORCE_SLEEP)
omap2_clkdm_sleep(clkdm);
}

return 0;
Expand Down
13 changes: 4 additions & 9 deletions arch/arm/mach-omap2/clockdomain44xx.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -95,13 +95,8 @@ static void omap4_clkdm_deny_idle(struct clockdomain *clkdm)

static int omap4_clkdm_clk_enable(struct clockdomain *clkdm)
{
bool hwsup = false;

hwsup = omap4_cminst_is_clkdm_in_hwsup(clkdm->prcm_partition,
clkdm->cm_inst, clkdm->clkdm_offs);

if (!hwsup)
clkdm_wakeup(clkdm);
if (clkdm->flags & CLKDM_CAN_FORCE_WAKEUP)
return omap4_clkdm_wakeup(clkdm);

return 0;
}
Expand All @@ -113,8 +108,8 @@ static int omap4_clkdm_clk_disable(struct clockdomain *clkdm)
hwsup = omap4_cminst_is_clkdm_in_hwsup(clkdm->prcm_partition,
clkdm->cm_inst, clkdm->clkdm_offs);

if (!hwsup)
clkdm_sleep(clkdm);
if (!hwsup && (clkdm->flags & CLKDM_CAN_FORCE_SLEEP))
omap4_clkdm_sleep(clkdm);

return 0;
}
Expand Down

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