diff mbox

ARM: OMAP2: UART: fix console UART mismatched runtime PM status

Message ID 1350344998-16328-1-git-send-email-khilman@deeprootsystems.com (mailing list archive)
State New, archived
Headers show

Commit Message

Kevin Hilman Oct. 15, 2012, 11:49 p.m. UTC
From: Kevin Hilman <khilman@ti.com>

The runtime PM framework assumes that the hardware state of devices
when initialized is disabled.  For all omap_devices, we idle/disable
device by default.  However, the console uart uses a "no idle" option
during omap_device init in order to allow earlyprintk usage to work
seamlessly during boot.

Because the hardware is left partially enabled after init (whatever
the bootloader settings were), the omap_device should later be fully
initialized (including mux) and the runtime PM framework should be
told that the device is active, and not disabled so that the hardware
state is in sync with runtime PM state.

To fix, after the device has been created/registered, call
omap_device_enable() to finialize init and use pm_runtime_set_active()
to tell the runtime PM core the device is enabled.

Tested on 2420/n810, 3530/Overo, 3530/Beagle, 3730/OveroSTORM,
3730/Beagle-xM, 4460/PandaES.

Reported-by: Paul Walmsley <paul@pwsan.com>
Suggested-by: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Felipe Balbi <balbi@ti.com>
Cc: Sourav Poddar <sourav.poddar@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>
---
Applies against v3.7-rc1.
Fix targetted for v3.7.

I'm still not entirely sure why this has worked up to now on OMAP3/4
but not on OMAP2.  Even so, this fix is needed for all platforms to
ensure matching hardware state and runtime PM state.

 arch/arm/mach-omap2/serial.c |    5 +++++
 1 file changed, 5 insertions(+)

Comments

Tony Lindgren Oct. 16, 2012, 12:01 a.m. UTC | #1
* Kevin Hilman <khilman@deeprootsystems.com> [121015 16:51]:
> From: Kevin Hilman <khilman@ti.com>
> 
> The runtime PM framework assumes that the hardware state of devices
> when initialized is disabled.  For all omap_devices, we idle/disable
> device by default.  However, the console uart uses a "no idle" option
> during omap_device init in order to allow earlyprintk usage to work
> seamlessly during boot.
> 
> Because the hardware is left partially enabled after init (whatever
> the bootloader settings were), the omap_device should later be fully
> initialized (including mux) and the runtime PM framework should be
> told that the device is active, and not disabled so that the hardware
> state is in sync with runtime PM state.
> 
> To fix, after the device has been created/registered, call
> omap_device_enable() to finialize init and use pm_runtime_set_active()
> to tell the runtime PM core the device is enabled.
> 
> Tested on 2420/n810, 3530/Overo, 3530/Beagle, 3730/OveroSTORM,
> 3730/Beagle-xM, 4460/PandaES.
> 
> Reported-by: Paul Walmsley <paul@pwsan.com>
> Suggested-by: Russell King <rmk+kernel@arm.linux.org.uk>
> Cc: Felipe Balbi <balbi@ti.com>
> Cc: Sourav Poddar <sourav.poddar@ti.com>
> Signed-off-by: Kevin Hilman <khilman@ti.com>

Seems to work for my n800:

Tested-by: Tony Lindgren <tony@atomide.com>
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Felipe Balbi Oct. 16, 2012, 10:25 a.m. UTC | #2
Hi,

On Mon, Oct 15, 2012 at 04:49:58PM -0700, Kevin Hilman wrote:
> From: Kevin Hilman <khilman@ti.com>
> 
> The runtime PM framework assumes that the hardware state of devices
> when initialized is disabled.  For all omap_devices, we idle/disable
> device by default.  However, the console uart uses a "no idle" option
> during omap_device init in order to allow earlyprintk usage to work
> seamlessly during boot.
> 
> Because the hardware is left partially enabled after init (whatever
> the bootloader settings were), the omap_device should later be fully
> initialized (including mux) and the runtime PM framework should be
> told that the device is active, and not disabled so that the hardware
> state is in sync with runtime PM state.
> 
> To fix, after the device has been created/registered, call
> omap_device_enable() to finialize init and use pm_runtime_set_active()
> to tell the runtime PM core the device is enabled.
> 
> Tested on 2420/n810, 3530/Overo, 3530/Beagle, 3730/OveroSTORM,
> 3730/Beagle-xM, 4460/PandaES.
> 
> Reported-by: Paul Walmsley <paul@pwsan.com>
> Suggested-by: Russell King <rmk+kernel@arm.linux.org.uk>
> Cc: Felipe Balbi <balbi@ti.com>
> Cc: Sourav Poddar <sourav.poddar@ti.com>
> Signed-off-by: Kevin Hilman <khilman@ti.com>
> ---
> Applies against v3.7-rc1.
> Fix targetted for v3.7.
> 
> I'm still not entirely sure why this has worked up to now on OMAP3/4
> but not on OMAP2.  Even so, this fix is needed for all platforms to
> ensure matching hardware state and runtime PM state.
> 
>  arch/arm/mach-omap2/serial.c |    5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c
> index 0405c81..37b5dbe 100644
> --- a/arch/arm/mach-omap2/serial.c
> +++ b/arch/arm/mach-omap2/serial.c
> @@ -327,6 +327,11 @@ void __init omap_serial_init_port(struct omap_board_data *bdata,
>  	if ((console_uart_id == bdata->id) && no_console_suspend)
>  		omap_device_disable_idle_on_suspend(pdev);
>  
> +	if (console_uart_id == bdata->id) {
> +		omap_device_enable(pdev);
> +		pm_runtime_set_active(&pdev->dev);
> +	}
> +
>  	oh->mux = omap_hwmod_mux_init(bdata->pads, bdata->pads_cnt);
>  
>  	oh->dev_attr = uart;

looks good to me. Even took care of doing that only for the console
UART.

Reviewed-by: Felipe Balbi <balbi@ti.com>

sorry for the issues caused.
Tony Lindgren Oct. 16, 2012, 9:18 p.m. UTC | #3
* Felipe Balbi <balbi@ti.com> [121016 03:32]:
> Hi,
> 
> On Mon, Oct 15, 2012 at 04:49:58PM -0700, Kevin Hilman wrote:
> > From: Kevin Hilman <khilman@ti.com>
> > 
> > The runtime PM framework assumes that the hardware state of devices
> > when initialized is disabled.  For all omap_devices, we idle/disable
> > device by default.  However, the console uart uses a "no idle" option
> > during omap_device init in order to allow earlyprintk usage to work
> > seamlessly during boot.
> > 
> > Because the hardware is left partially enabled after init (whatever
> > the bootloader settings were), the omap_device should later be fully
> > initialized (including mux) and the runtime PM framework should be
> > told that the device is active, and not disabled so that the hardware
> > state is in sync with runtime PM state.
> > 
> > To fix, after the device has been created/registered, call
> > omap_device_enable() to finialize init and use pm_runtime_set_active()
> > to tell the runtime PM core the device is enabled.
> > 
> > Tested on 2420/n810, 3530/Overo, 3530/Beagle, 3730/OveroSTORM,
> > 3730/Beagle-xM, 4460/PandaES.
> > 
> > Reported-by: Paul Walmsley <paul@pwsan.com>
> > Suggested-by: Russell King <rmk+kernel@arm.linux.org.uk>
> > Cc: Felipe Balbi <balbi@ti.com>
> > Cc: Sourav Poddar <sourav.poddar@ti.com>
> > Signed-off-by: Kevin Hilman <khilman@ti.com>
> > ---
> > Applies against v3.7-rc1.
> > Fix targetted for v3.7.
> > 
> > I'm still not entirely sure why this has worked up to now on OMAP3/4
> > but not on OMAP2.  Even so, this fix is needed for all platforms to
> > ensure matching hardware state and runtime PM state.
> > 
> >  arch/arm/mach-omap2/serial.c |    5 +++++
> >  1 file changed, 5 insertions(+)
> > 
> > diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c
> > index 0405c81..37b5dbe 100644
> > --- a/arch/arm/mach-omap2/serial.c
> > +++ b/arch/arm/mach-omap2/serial.c
> > @@ -327,6 +327,11 @@ void __init omap_serial_init_port(struct omap_board_data *bdata,
> >  	if ((console_uart_id == bdata->id) && no_console_suspend)
> >  		omap_device_disable_idle_on_suspend(pdev);
> >  
> > +	if (console_uart_id == bdata->id) {
> > +		omap_device_enable(pdev);
> > +		pm_runtime_set_active(&pdev->dev);
> > +	}
> > +
> >  	oh->mux = omap_hwmod_mux_init(bdata->pads, bdata->pads_cnt);
> >  
> >  	oh->dev_attr = uart;
> 
> looks good to me. Even took care of doing that only for the console
> UART.

Applying into omap-for-v3.7-rc1/fixes-take3.

Regards,

Tony
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Kevin Hilman Oct. 17, 2012, 1:03 a.m. UTC | #4
Tony Lindgren <tony@atomide.com> writes:

> * Felipe Balbi <balbi@ti.com> [121016 03:32]:
>> Hi,
>> 
>> On Mon, Oct 15, 2012 at 04:49:58PM -0700, Kevin Hilman wrote:
>> > From: Kevin Hilman <khilman@ti.com>
>> > 
>> > The runtime PM framework assumes that the hardware state of devices
>> > when initialized is disabled.  For all omap_devices, we idle/disable
>> > device by default.  However, the console uart uses a "no idle" option
>> > during omap_device init in order to allow earlyprintk usage to work
>> > seamlessly during boot.
>> > 
>> > Because the hardware is left partially enabled after init (whatever
>> > the bootloader settings were), the omap_device should later be fully
>> > initialized (including mux) and the runtime PM framework should be
>> > told that the device is active, and not disabled so that the hardware
>> > state is in sync with runtime PM state.
>> > 
>> > To fix, after the device has been created/registered, call
>> > omap_device_enable() to finialize init and use pm_runtime_set_active()
>> > to tell the runtime PM core the device is enabled.
>> > 
>> > Tested on 2420/n810, 3530/Overo, 3530/Beagle, 3730/OveroSTORM,
>> > 3730/Beagle-xM, 4460/PandaES.
>> > 
>> > Reported-by: Paul Walmsley <paul@pwsan.com>
>> > Suggested-by: Russell King <rmk+kernel@arm.linux.org.uk>
>> > Cc: Felipe Balbi <balbi@ti.com>
>> > Cc: Sourav Poddar <sourav.poddar@ti.com>
>> > Signed-off-by: Kevin Hilman <khilman@ti.com>
>> > ---
>> > Applies against v3.7-rc1.
>> > Fix targetted for v3.7.
>> > 
>> > I'm still not entirely sure why this has worked up to now on OMAP3/4
>> > but not on OMAP2.  Even so, this fix is needed for all platforms to
>> > ensure matching hardware state and runtime PM state.
>> > 
>> >  arch/arm/mach-omap2/serial.c |    5 +++++
>> >  1 file changed, 5 insertions(+)
>> > 
>> > diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c
>> > index 0405c81..37b5dbe 100644
>> > --- a/arch/arm/mach-omap2/serial.c
>> > +++ b/arch/arm/mach-omap2/serial.c
>> > @@ -327,6 +327,11 @@ void __init omap_serial_init_port(struct omap_board_data *bdata,
>> >  	if ((console_uart_id == bdata->id) && no_console_suspend)
>> >  		omap_device_disable_idle_on_suspend(pdev);
>> >  
>> > +	if (console_uart_id == bdata->id) {
>> > +		omap_device_enable(pdev);
>> > +		pm_runtime_set_active(&pdev->dev);
>> > +	}
>> > +
>> >  	oh->mux = omap_hwmod_mux_init(bdata->pads, bdata->pads_cnt);
>> >  
>> >  	oh->dev_attr = uart;
>> 
>> looks good to me. Even took care of doing that only for the console
>> UART.
>
> Applying into omap-for-v3.7-rc1/fixes-take3.
>

Doh, this isn't quite right yet.  Some more PM testing shows that UART
wakeups are broken, so this isn't ready for v3.7 yet.

To be continued...

Kevin

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Tony Lindgren Oct. 17, 2012, 2:14 a.m. UTC | #5
* Kevin Hilman <khilman@deeprootsystems.com> [121016 18:04]:
> 
> Doh, this isn't quite right yet.  Some more PM testing shows that UART
> wakeups are broken, so this isn't ready for v3.7 yet.

OK I'll drop it then.

Tony
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Russell King - ARM Linux Oct. 17, 2012, 8:28 a.m. UTC | #6
On Mon, Oct 15, 2012 at 04:49:58PM -0700, Kevin Hilman wrote:
> From: Kevin Hilman <khilman@ti.com>
> 
> The runtime PM framework assumes that the hardware state of devices
> when initialized is disabled.  For all omap_devices, we idle/disable
> device by default.  However, the console uart uses a "no idle" option
> during omap_device init in order to allow earlyprintk usage to work
> seamlessly during boot.
> 
> Because the hardware is left partially enabled after init (whatever
> the bootloader settings were), the omap_device should later be fully
> initialized (including mux) and the runtime PM framework should be
> told that the device is active, and not disabled so that the hardware
> state is in sync with runtime PM state.
> 
> To fix, after the device has been created/registered, call
> omap_device_enable() to finialize init and use pm_runtime_set_active()
> to tell the runtime PM core the device is enabled.

I still believe you're better off with the approach I gave.  Why?
Because every driver you have contains virtually the same sequence of
runtime PM "initialization" which is to runtime PM enable the device
and then do a get on it.

Why not do that in bus code if all your drivers are doing the same
thing, and kill off a bunch of code in the drivers?

It's fairly easy to do with the BUS_NOTIFY_BIND_DRIVER / BUS_NOTIFY_UNBIND_DRIVER
bus level notifies, and you've already hooked the notifier list for
these callbacks in omap_device.c
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diff mbox

Patch

diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c
index 0405c81..37b5dbe 100644
--- a/arch/arm/mach-omap2/serial.c
+++ b/arch/arm/mach-omap2/serial.c
@@ -327,6 +327,11 @@  void __init omap_serial_init_port(struct omap_board_data *bdata,
 	if ((console_uart_id == bdata->id) && no_console_suspend)
 		omap_device_disable_idle_on_suspend(pdev);
 
+	if (console_uart_id == bdata->id) {
+		omap_device_enable(pdev);
+		pm_runtime_set_active(&pdev->dev);
+	}
+
 	oh->mux = omap_hwmod_mux_init(bdata->pads, bdata->pads_cnt);
 
 	oh->dev_attr = uart;