diff mbox

[RESEND,PATCHv2,08/28] ARM: OMAP2+: clockdomain: add usecounting support to autoidle APIs

Message ID 1465844702-12200-9-git-send-email-t-kristo@ti.com (mailing list archive)
State New, archived
Headers show

Commit Message

Tero Kristo June 13, 2016, 7:04 p.m. UTC
The previous implementation was racy in many locations, where the current
status of the clockdomain was read out, some operations were executed,
and the previous status info was used afterwards to decide next state
for the clockdomain. Instead, fix the implementation of the allow_idle /
deny_idle APIs to properly have usecounting support. This allows clean
handling internally within the clockdomain core, and simplifies the
usage also within hwmod.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
---
 arch/arm/mach-omap2/clockdomain.c | 36 ++++++++++++++++++++++++------------
 arch/arm/mach-omap2/clockdomain.h |  2 ++
 arch/arm/mach-omap2/cpuidle44xx.c |  2 +-
 arch/arm/mach-omap2/omap-smp.c    |  2 +-
 arch/arm/mach-omap2/omap_hwmod.c  | 27 ++++++++++++---------------
 arch/arm/mach-omap2/pm.c          |  8 +-------
 arch/arm/mach-omap2/powerdomain.c | 20 ++++++--------------
 7 files changed, 47 insertions(+), 50 deletions(-)

Comments

Nishanth Menon June 13, 2016, 11:31 p.m. UTC | #1
On 06/13/2016 02:04 PM, Tero Kristo wrote:
[..]
> diff --git a/arch/arm/mach-omap2/omap_hwmod.c
b/arch/arm/mach-omap2/omap_hwmod.c
> index 0c85f91..635a563 100644
> --- a/arch/arm/mach-omap2/omap_hwmod.c
> +++ b/arch/arm/mach-omap2/omap_hwmod.c

[...]

> @@ -2177,14 +2173,10 @@ static int _enable(struct omap_hwmod *oh)
>  
>  	r = (soc_ops.wait_target_ready) ? soc_ops.wait_target_ready(oh) :
>  		-EINVAL;
> -	if (!r) {
> -		/*
> -		 * Set the clockdomain to HW_AUTO only if the target is ready,
> -		 * assuming that the previous state was HW_AUTO
> -		 */
> -		if (oh->clkdm && hwsup)
> -			clkdm_allow_idle(oh->clkdm);
> +	if (oh->clkdm)
> +		clkdm_allow_idle(oh->clkdm);

Should'nt this be under if (!r) ?

>  
> +	if (!r) {

here?
Tero Kristo June 14, 2016, 6:31 a.m. UTC | #2
On 14/06/16 02:31, Nishanth Menon wrote:
> On 06/13/2016 02:04 PM, Tero Kristo wrote:
> [..]
>> diff --git a/arch/arm/mach-omap2/omap_hwmod.c
> b/arch/arm/mach-omap2/omap_hwmod.c
>> index 0c85f91..635a563 100644
>> --- a/arch/arm/mach-omap2/omap_hwmod.c
>> +++ b/arch/arm/mach-omap2/omap_hwmod.c
>
> [...]
>
>> @@ -2177,14 +2173,10 @@ static int _enable(struct omap_hwmod *oh)
>>
>>   	r = (soc_ops.wait_target_ready) ? soc_ops.wait_target_ready(oh) :
>>   		-EINVAL;
>> -	if (!r) {
>> -		/*
>> -		 * Set the clockdomain to HW_AUTO only if the target is ready,
>> -		 * assuming that the previous state was HW_AUTO
>> -		 */
>> -		if (oh->clkdm && hwsup)
>> -			clkdm_allow_idle(oh->clkdm);
>> +	if (oh->clkdm)
>> +		clkdm_allow_idle(oh->clkdm);
>
> Should'nt this be under if (!r) ?

No, we must call clkdm_allow_idle() always, otherwise the clockdomain is 
left in force wakeup state for all eternity, which is wrong, and 
prevents any further transitions on the clockdomain. (Most likely the 
failed transition on the hwmod itself is going to prevent idle on the 
clockdomain though, but its better to keep at least the clockdomain 
state sane.)

-Tero
Tony Lindgren June 28, 2016, 7:06 a.m. UTC | #3
* Tero Kristo <t-kristo@ti.com> [160613 12:08]:
> The previous implementation was racy in many locations, where the current
> status of the clockdomain was read out, some operations were executed,
> and the previous status info was used afterwards to decide next state
> for the clockdomain. Instead, fix the implementation of the allow_idle /
> deny_idle APIs to properly have usecounting support. This allows clean
> handling internally within the clockdomain core, and simplifies the
> usage also within hwmod.

Acked-by: Tony Lindgren <tony@atomide.com>

Or let me know if this can be picked separately.

Tony
diff mbox

Patch

diff --git a/arch/arm/mach-omap2/clockdomain.c b/arch/arm/mach-omap2/clockdomain.c
index 2da3b5e..b79b1ca 100644
--- a/arch/arm/mach-omap2/clockdomain.c
+++ b/arch/arm/mach-omap2/clockdomain.c
@@ -465,10 +465,7 @@  int clkdm_complete_init(void)
 		return -EACCES;
 
 	list_for_each_entry(clkdm, &clkdm_list, node) {
-		if (clkdm->flags & CLKDM_CAN_FORCE_WAKEUP)
-			clkdm_wakeup(clkdm);
-		else if (clkdm->flags & CLKDM_CAN_DISABLE_AUTO)
-			clkdm_deny_idle(clkdm);
+		clkdm_deny_idle(clkdm);
 
 		_resolve_clkdm_deps(clkdm, clkdm->wkdep_srcs);
 		clkdm_clear_all_wkdeps(clkdm);
@@ -925,11 +922,20 @@  void clkdm_allow_idle_nolock(struct clockdomain *clkdm)
 	if (!clkdm)
 		return;
 
-	if (!(clkdm->flags & CLKDM_CAN_ENABLE_AUTO)) {
-		pr_debug("clock: %s: automatic idle transitions cannot be enabled\n",
-			 clkdm->name);
+	if (!WARN_ON(!clkdm->forcewake_count))
+		clkdm->forcewake_count--;
+
+	if (clkdm->forcewake_count)
+		return;
+
+	if (!clkdm->usecount && (clkdm->flags & CLKDM_CAN_FORCE_SLEEP))
+		clkdm_sleep_nolock(clkdm);
+
+	if (!(clkdm->flags & CLKDM_CAN_ENABLE_AUTO))
+		return;
+
+	if (clkdm->flags & CLKDM_MISSING_IDLE_REPORTING)
 		return;
-	}
 
 	if (!arch_clkdm || !arch_clkdm->clkdm_allow_idle)
 		return;
@@ -974,11 +980,17 @@  void clkdm_deny_idle_nolock(struct clockdomain *clkdm)
 	if (!clkdm)
 		return;
 
-	if (!(clkdm->flags & CLKDM_CAN_DISABLE_AUTO)) {
-		pr_debug("clockdomain: %s: automatic idle transitions cannot be disabled\n",
-			 clkdm->name);
+	if (clkdm->forcewake_count++)
+		return;
+
+	if (clkdm->flags & CLKDM_CAN_FORCE_WAKEUP)
+		clkdm_wakeup_nolock(clkdm);
+
+	if (!(clkdm->flags & CLKDM_CAN_DISABLE_AUTO))
+		return;
+
+	if (clkdm->flags & CLKDM_MISSING_IDLE_REPORTING)
 		return;
-	}
 
 	if (!arch_clkdm || !arch_clkdm->clkdm_deny_idle)
 		return;
diff --git a/arch/arm/mach-omap2/clockdomain.h b/arch/arm/mach-omap2/clockdomain.h
index 2c398ce..24667a5 100644
--- a/arch/arm/mach-omap2/clockdomain.h
+++ b/arch/arm/mach-omap2/clockdomain.h
@@ -114,6 +114,7 @@  struct omap_hwmod;
  * @wkdep_srcs: Clockdomains that can be told to wake this powerdomain up
  * @sleepdep_srcs: Clockdomains that can be told to keep this clkdm from inact
  * @usecount: Usecount tracking
+ * @forcewake_count: Usecount for forcing the domain active
  * @node: list_head to link all clockdomains together
  *
  * @prcm_partition should be a macro from mach-omap2/prcm44xx.h (OMAP4 only)
@@ -138,6 +139,7 @@  struct clockdomain {
 	struct clkdm_dep *wkdep_srcs;
 	struct clkdm_dep *sleepdep_srcs;
 	int usecount;
+	int forcewake_count;
 	struct list_head node;
 };
 
diff --git a/arch/arm/mach-omap2/cpuidle44xx.c b/arch/arm/mach-omap2/cpuidle44xx.c
index 4b8e9f4..fa138d4 100644
--- a/arch/arm/mach-omap2/cpuidle44xx.c
+++ b/arch/arm/mach-omap2/cpuidle44xx.c
@@ -140,7 +140,7 @@  static int omap_enter_idle_coupled(struct cpuidle_device *dev,
 		    mpuss_can_lose_context)
 			gic_dist_disable();
 
-		clkdm_wakeup(cpu_clkdm[1]);
+		clkdm_deny_idle(cpu_clkdm[1]);
 		omap_set_pwrdm_state(cpu_pd[1], PWRDM_POWER_ON);
 		clkdm_allow_idle(cpu_clkdm[1]);
 
diff --git a/arch/arm/mach-omap2/omap-smp.c b/arch/arm/mach-omap2/omap-smp.c
index c625cc1..690bfa5 100644
--- a/arch/arm/mach-omap2/omap-smp.c
+++ b/arch/arm/mach-omap2/omap-smp.c
@@ -143,7 +143,7 @@  static int omap4_boot_secondary(unsigned int cpu, struct task_struct *idle)
 		 * Ensure that CPU power state is set to ON to avoid CPU
 		 * powerdomain transition on wfi
 		 */
-		clkdm_wakeup_nolock(cpu1_clkdm);
+		clkdm_deny_idle_nolock(cpu1_clkdm);
 		pwrdm_set_next_pwrst(cpu1_pwrdm, PWRDM_POWER_ON);
 		clkdm_allow_idle_nolock(cpu1_clkdm);
 
diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
index 0c85f91..635a563 100644
--- a/arch/arm/mach-omap2/omap_hwmod.c
+++ b/arch/arm/mach-omap2/omap_hwmod.c
@@ -1696,7 +1696,6 @@  static int _deassert_hardreset(struct omap_hwmod *oh, const char *name)
 {
 	struct omap_hwmod_rst_info ohri;
 	int ret = -EINVAL;
-	int hwsup = 0;
 
 	if (!oh)
 		return -EINVAL;
@@ -1714,7 +1713,7 @@  static int _deassert_hardreset(struct omap_hwmod *oh, const char *name)
 		 * might not be completed. The clockdomain can be set
 		 * in HW_AUTO only when the module become ready.
 		 */
-		hwsup = clkdm_in_hwsup(oh->clkdm);
+		clkdm_deny_idle(oh->clkdm);
 		ret = clkdm_hwmod_enable(oh->clkdm, oh);
 		if (ret) {
 			WARN(1, "omap_hwmod: %s: could not enable clockdomain %s: %d\n",
@@ -1741,8 +1740,7 @@  static int _deassert_hardreset(struct omap_hwmod *oh, const char *name)
 		 * Set the clockdomain to HW_AUTO, assuming that the
 		 * previous state was HW_AUTO.
 		 */
-		if (hwsup)
-			clkdm_allow_idle(oh->clkdm);
+		clkdm_allow_idle(oh->clkdm);
 
 		clkdm_hwmod_disable(oh->clkdm, oh);
 	}
@@ -2096,7 +2094,6 @@  static int _enable_preprogram(struct omap_hwmod *oh)
 static int _enable(struct omap_hwmod *oh)
 {
 	int r;
-	int hwsup = 0;
 
 	pr_debug("omap_hwmod: %s: enabling\n", oh->name);
 
@@ -2156,8 +2153,7 @@  static int _enable(struct omap_hwmod *oh)
 		 * completely the module. The clockdomain can be set
 		 * in HW_AUTO only when the module become ready.
 		 */
-		hwsup = clkdm_in_hwsup(oh->clkdm) &&
-			!clkdm_missing_idle_reporting(oh->clkdm);
+		clkdm_deny_idle(oh->clkdm);
 		r = clkdm_hwmod_enable(oh->clkdm, oh);
 		if (r) {
 			WARN(1, "omap_hwmod: %s: could not enable clockdomain %s: %d\n",
@@ -2177,14 +2173,10 @@  static int _enable(struct omap_hwmod *oh)
 
 	r = (soc_ops.wait_target_ready) ? soc_ops.wait_target_ready(oh) :
 		-EINVAL;
-	if (!r) {
-		/*
-		 * Set the clockdomain to HW_AUTO only if the target is ready,
-		 * assuming that the previous state was HW_AUTO
-		 */
-		if (oh->clkdm && hwsup)
-			clkdm_allow_idle(oh->clkdm);
+	if (oh->clkdm)
+		clkdm_allow_idle(oh->clkdm);
 
+	if (!r) {
 		oh->_state = _HWMOD_STATE_ENABLED;
 
 		/* Access the sysconfig only if the target is ready */
@@ -2238,6 +2230,9 @@  static int _idle(struct omap_hwmod *oh)
 		_idle_sysc(oh);
 	_del_initiator_dep(oh, mpu_oh);
 
+	if (oh->clkdm)
+		clkdm_deny_idle(oh->clkdm);
+
 	if (oh->flags & HWMOD_BLOCK_WFI)
 		cpu_idle_poll_ctrl(false);
 	if (soc_ops.disable_module)
@@ -2250,8 +2245,10 @@  static int _idle(struct omap_hwmod *oh)
 	 * transition to complete properly.
 	 */
 	_disable_clocks(oh);
-	if (oh->clkdm)
+	if (oh->clkdm) {
+		clkdm_allow_idle(oh->clkdm);
 		clkdm_hwmod_disable(oh->clkdm, oh);
+	}
 
 	/* Mux pins for device idle if populated */
 	if (oh->mux && oh->mux->pads_dynamic) {
diff --git a/arch/arm/mach-omap2/pm.c b/arch/arm/mach-omap2/pm.c
index 37c80f5..12a5ece 100644
--- a/arch/arm/mach-omap2/pm.c
+++ b/arch/arm/mach-omap2/pm.c
@@ -110,13 +110,7 @@  static void __init omap2_init_processor_devices(void)
 
 int __init omap_pm_clkdms_setup(struct clockdomain *clkdm, void *unused)
 {
-	/* XXX The usecount test is racy */
-	if ((clkdm->flags & CLKDM_CAN_ENABLE_AUTO) &&
-	    !(clkdm->flags & CLKDM_MISSING_IDLE_REPORTING))
-		clkdm_allow_idle(clkdm);
-	else if (clkdm->flags & CLKDM_CAN_FORCE_SLEEP &&
-		 clkdm->usecount == 0)
-		clkdm_sleep(clkdm);
+	clkdm_allow_idle(clkdm);
 	return 0;
 }
 
diff --git a/arch/arm/mach-omap2/powerdomain.c b/arch/arm/mach-omap2/powerdomain.c
index 78af6d8..be7a976 100644
--- a/arch/arm/mach-omap2/powerdomain.c
+++ b/arch/arm/mach-omap2/powerdomain.c
@@ -222,7 +222,6 @@  static int _pwrdm_post_transition_cb(struct powerdomain *pwrdm, void *unused)
  * @pwrdm: struct powerdomain * to operate on
  * @curr_pwrst: current power state of @pwrdm
  * @pwrst: power state to switch to
- * @hwsup: ptr to a bool to return whether the clkdm is hardware-supervised
  *
  * Determine whether the powerdomain needs to be turned on before
  * attempting to switch power states.  Called by
@@ -233,8 +232,7 @@  static int _pwrdm_post_transition_cb(struct powerdomain *pwrdm, void *unused)
  * "Types of sleep_switch" comment above).
  */
 static u8 _pwrdm_save_clkdm_state_and_activate(struct powerdomain *pwrdm,
-					       u8 curr_pwrst, u8 pwrst,
-					       bool *hwsup)
+					       u8 curr_pwrst, u8 pwrst)
 {
 	u8 sleep_switch;
 
@@ -244,8 +242,7 @@  static u8 _pwrdm_save_clkdm_state_and_activate(struct powerdomain *pwrdm,
 		    arch_pwrdm->pwrdm_set_lowpwrstchange) {
 			sleep_switch = LOWPOWERSTATE_SWITCH;
 		} else {
-			*hwsup = clkdm_in_hwsup(pwrdm->pwrdm_clkdms[0]);
-			clkdm_wakeup_nolock(pwrdm->pwrdm_clkdms[0]);
+			clkdm_deny_idle_nolock(pwrdm->pwrdm_clkdms[0]);
 			sleep_switch = FORCEWAKEUP_SWITCH;
 		}
 	} else {
@@ -259,7 +256,6 @@  static u8 _pwrdm_save_clkdm_state_and_activate(struct powerdomain *pwrdm,
  * _pwrdm_restore_clkdm_state - restore the clkdm hwsup state after pwrst change
  * @pwrdm: struct powerdomain * to operate on
  * @sleep_switch: return value from _pwrdm_save_clkdm_state_and_activate()
- * @hwsup: should @pwrdm's first clockdomain be set to hardware-supervised mode?
  *
  * Restore the clockdomain state perturbed by
  * _pwrdm_save_clkdm_state_and_activate(), and call the power state
@@ -270,14 +266,11 @@  static u8 _pwrdm_save_clkdm_state_and_activate(struct powerdomain *pwrdm,
  * software-supervised sleep.  No return value.
  */
 static void _pwrdm_restore_clkdm_state(struct powerdomain *pwrdm,
-				       u8 sleep_switch, bool hwsup)
+				       u8 sleep_switch)
 {
 	switch (sleep_switch) {
 	case FORCEWAKEUP_SWITCH:
-		if (hwsup)
-			clkdm_allow_idle_nolock(pwrdm->pwrdm_clkdms[0]);
-		else
-			clkdm_sleep_nolock(pwrdm->pwrdm_clkdms[0]);
+		clkdm_allow_idle_nolock(pwrdm->pwrdm_clkdms[0]);
 		break;
 	case LOWPOWERSTATE_SWITCH:
 		if (pwrdm->flags & PWRDM_HAS_LOWPOWERSTATECHANGE &&
@@ -1092,7 +1085,6 @@  int omap_set_pwrdm_state(struct powerdomain *pwrdm, u8 pwrst)
 	u8 next_pwrst, sleep_switch;
 	int curr_pwrst;
 	int ret = 0;
-	bool hwsup = false;
 
 	if (!pwrdm || IS_ERR(pwrdm))
 		return -EINVAL;
@@ -1116,14 +1108,14 @@  int omap_set_pwrdm_state(struct powerdomain *pwrdm, u8 pwrst)
 		goto osps_out;
 
 	sleep_switch = _pwrdm_save_clkdm_state_and_activate(pwrdm, curr_pwrst,
-							    pwrst, &hwsup);
+							    pwrst);
 
 	ret = pwrdm_set_next_pwrst(pwrdm, pwrst);
 	if (ret)
 		pr_err("%s: unable to set power state of powerdomain: %s\n",
 		       __func__, pwrdm->name);
 
-	_pwrdm_restore_clkdm_state(pwrdm, sleep_switch, hwsup);
+	_pwrdm_restore_clkdm_state(pwrdm, sleep_switch);
 
 osps_out:
 	pwrdm_unlock(pwrdm);