Hi Kevin,
a few questions:
On Wed, 3 Feb 2010, Kevin Hilman wrote:
> Add new function omap_device_has_lost_context() as a simple check
> to be used after omap_device_enable() to determine if device has
> lost context (and thus needs context restore.)
>
> Motivation: Currently, each driver needs to read the context-loss
> count before suspend, and again upon resume to determine if
> device context needs to be restored. Rather than duplicating
> this process across all drivers, move it into omap_device. After
> omap_device_enable(), omap_device_has_lost_context() can be called
> to determine if context was lost.
>
> This API is not intended for direct use by drivers. Rather, the
> OMAP runtime PM core will use this to determine whether or not
> to call the drivers runtime_resume hook which can then be used to
> restore context.
>
> The goal is to only call drivers "restore" hook when necessary.
>
> Signed-off-by: Kevin Hilman <khilman@xxxxxxxxxxxxxxxxxxx>
> ---
> arch/arm/plat-omap/include/plat/omap_device.h | 3 ++
> arch/arm/plat-omap/omap_device.c | 35 +++++++++++++++++++++++++
> 2 files changed, 38 insertions(+), 0 deletions(-)
>
> diff --git a/arch/arm/plat-omap/include/plat/omap_device.h b/arch/arm/plat-omap/include/plat/omap_device.h
> index 76d4917..ff98eb4 100644
> --- a/arch/arm/plat-omap/include/plat/omap_device.h
> +++ b/arch/arm/plat-omap/include/plat/omap_device.h
> @@ -71,6 +71,8 @@ struct omap_device {
> s8 pm_lat_level;
> u8 hwmods_cnt;
> u8 _state;
> + u32 activate_loss_cnt;
> + u32 deactivate_loss_cnt;
Would it be sufficient to just note the context loss count on a disable
and then compare it against the powerdomain's loss count during activate,
and if different, set a flag in _state ? That way only one loss count
variable would be needed.
> };
>
> /* Device driver interface (call via platform_data fn ptrs) */
> @@ -78,6 +80,7 @@ struct omap_device {
> int omap_device_enable(struct platform_device *pdev);
> int omap_device_idle(struct platform_device *pdev);
> int omap_device_shutdown(struct platform_device *pdev);
> +bool omap_device_has_lost_context(struct platform_device *pdev);
>
> /* Core code interface */
>
> diff --git a/arch/arm/plat-omap/omap_device.c b/arch/arm/plat-omap/omap_device.c
> index d8c75c8..aaa009d 100644
> --- a/arch/arm/plat-omap/omap_device.c
> +++ b/arch/arm/plat-omap/omap_device.c
> @@ -84,6 +84,7 @@
>
> #include <plat/omap_device.h>
> #include <plat/omap_hwmod.h>
> +#include <plat/powerdomain.h>
>
> /* These parameters are passed to _omap_device_{de,}activate() */
> #define USE_WAKEUP_LAT 0
> @@ -119,6 +120,7 @@
> static int _omap_device_activate(struct omap_device *od, u8 ignore_lat)
> {
> struct timespec a, b, c;
> + struct powerdomain *pwrdm;
>
> pr_debug("omap_device: %s: activating\n", od->pdev.name);
>
> @@ -168,6 +170,10 @@ static int _omap_device_activate(struct omap_device *od, u8 ignore_lat)
> od->dev_wakeup_lat -= odpl->activate_lat;
> }
>
> + pwrdm = omap_device_get_pwrdm(od);
> + if (pwrdm)
> + od->activate_loss_cnt = pwrdm->state_counter[PWRDM_POWER_OFF];
This probably will also depend on the powerdomain's logic_retst,
mem_retst, mem_onst bits, since context can be lost even when the
powerdomain is in RET or ON state.
> +
> return 0;
> }
>
> @@ -188,6 +194,7 @@ static int _omap_device_activate(struct omap_device *od, u8 ignore_lat)
> static int _omap_device_deactivate(struct omap_device *od, u8 ignore_lat)
> {
> struct timespec a, b, c;
> + struct powerdomain *pwrdm;
>
> pr_debug("omap_device: %s: deactivating\n", od->pdev.name);
>
> @@ -239,6 +246,10 @@ static int _omap_device_deactivate(struct omap_device *od, u8 ignore_lat)
> od->pm_lat_level++;
> }
>
> + pwrdm = omap_device_get_pwrdm(od);
> + if (pwrdm)
> + od->deactivate_loss_cnt = pwrdm->state_counter[PWRDM_POWER_OFF];
Same comment as above.
> +
> return 0;
> }
>
> @@ -560,6 +571,30 @@ int omap_device_shutdown(struct platform_device *pdev)
> }
>
> /**
> + * omap_device_has_lost_context() - check if omap_device has lost context
> + * @od: struct omap_device *
> + *
> + * When an omap_device has been deactivated via omap_device_idle() or
> + * omap_device_shutdown() and then (re)activated using omap_device_enable()
> + * This function should be used to determine if the omap_device has
> + * lost context (due to an off-mode transistion)
> + */
> +bool omap_device_has_lost_context(struct platform_device *pdev)
> +{
> + struct omap_device *od;
> +
> + od = _find_by_pdev(pdev);
> +
> + if (od->_state != OMAP_DEVICE_STATE_ENABLED) {
> + WARN(1, "omap_device: %s.%d: has_lost_context() called "
> + "from invalid state\n", od->pdev.name, od->pdev.id);
> + return -EINVAL;
> + }
> +
> + return (od->activate_loss_cnt != od->deactivate_loss_cnt);
> +}
> +
> +/**
> * omap_device_align_pm_lat - activate/deactivate device to match wakeup lat lim
> * @od: struct omap_device *
> *
> --
> 1.6.6
>
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>
- Paul
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