[PATCH v2] ARM: OMAP2+: hwmod: Add a new state to handle hwmods left enabled at init

[PATCH v2] ARM: OMAP2+: hwmod: Add a new state to handle hwmods left enabled at init

[Rajendra Nayak]

An hwmod with a 'HWMOD_INIT_NO_IDLE' flag set, is left in
enabled state by the hwmod framework post the initial setup.
Once a real user of the device (a driver) tries to enable it
at a later point, the hwmod framework throws a WARN() about
the device being already in enabled state.

Fix this by introducing a new state '_HWMOD_STATE_ENABLED_AT_INIT'
to identify such devices/hwmods, so nothing but just a state
change to '_HWMOD_STATE_ENABLED' can be done when the device/hwmod
is requested to be enabled (the first time) by its driver/user.

A good example of a such a device is an UART used as debug console.
The UART module needs to be kept enabled through the boot, until the
UART driver takes control of it, for debug prints to appear on
the console.

Acked-by: Kevin Hilman <khilman@ti.com>
Acked-by: Benoit Cousson <b-cousson@ti.com>
Signed-off-by: Rajendra Nayak <rnayak@ti.com>
---
changes in v2:
Fixed minor typos, removed stay change, updated comment
in header.

 arch/arm/mach-omap2/omap_hwmod.c             |   15 ++++++++++++++-
 arch/arm/plat-omap/include/plat/omap_hwmod.h |    6 ++++++
 2 files changed, 20 insertions(+), 1 deletions(-)

diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
index 6b3088d..72ee723 100644
--- a/arch/arm/mach-omap2/omap_hwmod.c
+++ b/arch/arm/mach-omap2/omap_hwmod.c
@@ -1441,6 +1441,17 @@ static int _enable(struct omap_hwmod *oh)
 
 	pr_debug("omap_hwmod: %s: enabling\n", oh->name);
 
+	/*
+	 * hwmods' with HWMOD_INIT_NO_IDLE flag set, are left
+	 * in enabled state at init.
+	 * Now that someone is really trying to enable them,
+	 * just update the state.
+	 */
+	if (oh->_state == _HWMOD_STATE_ENABLED_AT_INIT) {
+		oh->_state = _HWMOD_STATE_ENABLED;
+		return 0;
+	}
+
 	if (oh->_state != _HWMOD_STATE_INITIALIZED &&
 	    oh->_state != _HWMOD_STATE_IDLE &&
 	    oh->_state != _HWMOD_STATE_DISABLED) {
@@ -1744,8 +1755,10 @@ static int _setup(struct omap_hwmod *oh, void *data)
 	 * it should be set by the core code as a runtime flag during startup
 	 */
 	if ((oh->flags & HWMOD_INIT_NO_IDLE) &&
-	    (postsetup_state == _HWMOD_STATE_IDLE))
+	    (postsetup_state == _HWMOD_STATE_IDLE)) {
+		oh->_state = _HWMOD_STATE_ENABLED_AT_INIT;
 		postsetup_state = _HWMOD_STATE_ENABLED;
+	}
 
 	if (postsetup_state == _HWMOD_STATE_IDLE)
 		_idle(oh);
diff --git a/arch/arm/plat-omap/include/plat/omap_hwmod.h b/arch/arm/plat-omap/include/plat/omap_hwmod.h
index 8b372ed..2bd3929 100644
--- a/arch/arm/plat-omap/include/plat/omap_hwmod.h
+++ b/arch/arm/plat-omap/include/plat/omap_hwmod.h
@@ -436,6 +436,12 @@ struct omap_hwmod_omap4_prcm {
 #define _HWMOD_STATE_ENABLED			4
 #define _HWMOD_STATE_IDLE			5
 #define _HWMOD_STATE_DISABLED			6
+/*
+ * This state signifies the hwmod was left enabled
+ * after init, by the framework, because of the
+ * 'HWMOD_INIT_NO_IDLE' flag.
+ */
+#define _HWMOD_STATE_ENABLED_AT_INIT		7
 
 /**
  * struct omap_hwmod_class - the type of an IP block
-- 
1.7.1

[PATCH v2] ARM: OMAP2+: hwmod: Add a new state to handle hwmods left enabled at init

[Govindraj]

Hi Rajendra,

On Mon, Nov 21, 2011 at 11:45 AM, Rajendra Nayak <rnayak@ti.com> wrote:
> An hwmod with a 'HWMOD_INIT_NO_IDLE' flag set, is left in
> enabled state by the hwmod framework post the initial setup.
> Once a real user of the device (a driver) tries to enable it
> at a later point, the hwmod framework throws a WARN() about
> the device being already in enabled state.
>
> Fix this by introducing a new state '_HWMOD_STATE_ENABLED_AT_INIT'
> to identify such devices/hwmods, so nothing but just a state
> change to '_HWMOD_STATE_ENABLED' can be done when the device/hwmod
> is requested to be enabled (the first time) by its driver/user.
>
> A good example of a such a device is an UART used as debug console.
> The UART module needs to be kept enabled through the boot, until the
> UART driver takes control of it, for debug prints to appear on
> the console.
>
> Acked-by: Kevin Hilman <khilman@ti.com>
> Acked-by: Benoit Cousson <b-cousson@ti.com>
> Signed-off-by: Rajendra Nayak <rnayak@ti.com>
> ---
> changes in v2:
> Fixed minor typos, removed stay change, updated comment
> in header.
>
> ?arch/arm/mach-omap2/omap_hwmod.c ? ? ? ? ? ? | ? 15 ++++++++++++++-
> ?arch/arm/plat-omap/include/plat/omap_hwmod.h | ? ?6 ++++++
> ?2 files changed, 20 insertions(+), 1 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
> index 6b3088d..72ee723 100644
> --- a/arch/arm/mach-omap2/omap_hwmod.c
> +++ b/arch/arm/mach-omap2/omap_hwmod.c
> @@ -1441,6 +1441,17 @@ static int _enable(struct omap_hwmod *oh)
>
> ? ? ? ?pr_debug("omap_hwmod: %s: enabling\n", oh->name);
>
> + ? ? ? /*
> + ? ? ? ?* hwmods' with HWMOD_INIT_NO_IDLE flag set, are left
> + ? ? ? ?* in enabled state at init.
> + ? ? ? ?* Now that someone is really trying to enable them,
> + ? ? ? ?* just update the state.
> + ? ? ? ?*/
> + ? ? ? if (oh->_state == _HWMOD_STATE_ENABLED_AT_INIT) {
> + ? ? ? ? ? ? ? oh->_state = _HWMOD_STATE_ENABLED;
> + ? ? ? ? ? ? ? return 0;
> + ? ? ? }
> +

one issue returning from here without doing
omap_hwmod_mux(oh->mux, _HWMOD_STATE_ENABLED);

causes hmux->enabled to be false after first _enable (get_sync)

and for first _idle(put/put_sync)

omap_hwmod_mux(oh->mux, _HWMOD_STATE_IDLE);
will not happen and will not enable rx_pad wake-up for uart.
so this is causing wake-up failures from off mode.

[code_snip]

void omap_hwmod_mux(struct omap_hwmod_mux_info *hmux, u8 state)
{
        int i;

         /* Runtime idling of dynamic pads */
        if (state == _HWMOD_STATE_IDLE && hmux->enabled) {
                for (i = 0; i < hmux->nr_pads_dynamic; i++) {
                        struct omap_device_pad *pad = hmux->pads_dynamic[i];
                        int val = -EINVAL;

                        val = pad->idle;
                        omap_mux_write(pad->partition, val,
                                        pad->mux->reg_offset);
                }

                return;
        }

       [..]

      if (state == _HWMOD_STATE_ENABLED)
                hmux->enabled = true;
      else
                hmux->enabled = false;
}

[..]

--
Thanks,
Govindraj.R

[PATCH v2] ARM: OMAP2+: hwmod: Add a new state to handle hwmods left enabled at init

[Rajendra Nayak]

On Monday 21 November 2011 03:33 PM, Govindraj wrote:
> Hi Rajendra,
>
> On Mon, Nov 21, 2011 at 11:45 AM, Rajendra Nayak<rnayak@ti.com>  wrote:
>> An hwmod with a 'HWMOD_INIT_NO_IDLE' flag set, is left in
>> enabled state by the hwmod framework post the initial setup.
>> Once a real user of the device (a driver) tries to enable it
>> at a later point, the hwmod framework throws a WARN() about
>> the device being already in enabled state.
>>
>> Fix this by introducing a new state '_HWMOD_STATE_ENABLED_AT_INIT'
>> to identify such devices/hwmods, so nothing but just a state
>> change to '_HWMOD_STATE_ENABLED' can be done when the device/hwmod
>> is requested to be enabled (the first time) by its driver/user.
>>
>> A good example of a such a device is an UART used as debug console.
>> The UART module needs to be kept enabled through the boot, until the
>> UART driver takes control of it, for debug prints to appear on
>> the console.
>>
>> Acked-by: Kevin Hilman<khilman@ti.com>
>> Acked-by: Benoit Cousson<b-cousson@ti.com>
>> Signed-off-by: Rajendra Nayak<rnayak@ti.com>
>> ---
>> changes in v2:
>> Fixed minor typos, removed stay change, updated comment
>> in header.
>>
>>   arch/arm/mach-omap2/omap_hwmod.c             |   15 ++++++++++++++-
>>   arch/arm/plat-omap/include/plat/omap_hwmod.h |    6 ++++++
>>   2 files changed, 20 insertions(+), 1 deletions(-)
>>
>> diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
>> index 6b3088d..72ee723 100644
>> --- a/arch/arm/mach-omap2/omap_hwmod.c
>> +++ b/arch/arm/mach-omap2/omap_hwmod.c
>> @@ -1441,6 +1441,17 @@ static int _enable(struct omap_hwmod *oh)
>>
>>         pr_debug("omap_hwmod: %s: enabling\n", oh->name);
>>
>> +       /*
>> +        * hwmods' with HWMOD_INIT_NO_IDLE flag set, are left
>> +        * in enabled state at init.
>> +        * Now that someone is really trying to enable them,
>> +        * just update the state.
>> +        */
>> +       if (oh->_state == _HWMOD_STATE_ENABLED_AT_INIT) {
>> +               oh->_state = _HWMOD_STATE_ENABLED;
>> +               return 0;
>> +       }
>> +
>
> one issue returning from here without doing
> omap_hwmod_mux(oh->mux, _HWMOD_STATE_ENABLED);
>
> causes hmux->enabled to be false after first _enable (get_sync)
>
> and for first _idle(put/put_sync)
>
> omap_hwmod_mux(oh->mux, _HWMOD_STATE_IDLE);
> will not happen and will not enable rx_pad wake-up for uart.
> so this is causing wake-up failures from off mode.

Ok, so this looks like is something that happens additionally
with a driver-enable, which does not happen as part of the
framework-enable (as part of setup).
Thanks for digging it up.

An easy way to fix it would be to handle the muxing along with the
state change..

if (oh->_state == _HWMOD_STATE_ENABLED_AT_INIT) {
	/*
	 * If the caller has mux data populated, do the mux'ing
	 * which wouldn't have been done as part of the _enable()
	 * done during setup.
	 */
	if (oh->mux)
		omap_hwmod_mux(oh->mux, _HWMOD_STATE_ENABLED);
	oh->_state = _HWMOD_STATE_ENABLED;
	return 0;
}

Will respin with the changes, and hopefully this should fix the wakeup
issues from OFF.

>