> -----Original Message-----
> From: Hilman, Kevin
> Sent: Friday, March 04, 2011 6:53 AM
> To: DebBarma, Tarun Kanti
> Cc: linux-omap@xxxxxxxxxxxxxxx; Basak, Partha
> Subject: Re: [PATCH v11 7/8] OMAP: dmtimer: pm_runtime support
>
> Tarun Kanti DebBarma <tarun.kanti@xxxxxx> writes:
>
> > Add pm_runtime support to dmtimer. Since dmtimer is used during
> > early boot before pm_runtime is initialized completely there are
> > provisions to enable/disable clocks directly in the code during
> > early boot.
>
> I'm still not crazy about the duplicate logic (both early & normal) in
> all the enable/disable functions.
>
> As I've suggested in the past, why not just do a clk_get, clk_enable in
> when the early timers are initialized, then do a clk_disable, clk_put()
> as soon as the "normal" device is ready and PM runtime is enabled.
>
> That will greatly simplify the code and eliminate the unnecessary checks
> for ->is_early_device which will always be false except for in early
> boot (when these functions are not likely to be called anyways.)
I will do the cleanup.
>
> > Signed-off-by: Tarun Kanti DebBarma <tarun.kanti@xxxxxx>
> > [p-basak2@xxxxxx: added pm_runtime logic in probe()]
> > Signed-off-by: Partha Basak <p-basak2@xxxxxx>
> > Reviewed-by: Varadarajan, Charulatha <charu@xxxxxx>
> > Acked-by: Cousson, Benoit <b-cousson@xxxxxx>
> > ---
> > arch/arm/plat-omap/dmtimer.c | 63
> ++++++++++++++++++++++++++++++++++++------
> > 1 files changed, 54 insertions(+), 9 deletions(-)
> >
> > diff --git a/arch/arm/plat-omap/dmtimer.c b/arch/arm/plat-omap/dmtimer.c
> > index 53f5205..fcac422 100644
> > --- a/arch/arm/plat-omap/dmtimer.c
> > +++ b/arch/arm/plat-omap/dmtimer.c
> > @@ -39,6 +39,7 @@
> > #include <linux/delay.h>
> > #include <linux/io.h>
> > #include <linux/slab.h>
> > +#include <linux/pm_runtime.h>
> > #include <linux/err.h>
> > #include <linux/platform_device.h>
> > #include <plat/dmtimer.h>
> > @@ -211,13 +212,16 @@ static void omap_dm_timer_prepare(struct
> omap_dm_timer *timer)
> > {
> > struct dmtimer_platform_data *pdata = timer->pdev->dev.platform_data;
> >
> > - timer->fclk = clk_get(&timer->pdev->dev, "fck");
> > - if (WARN_ON_ONCE(IS_ERR_OR_NULL(timer->fclk))) {
> > - dev_err(&timer->pdev->dev, ": No fclk handle.\n");
> > - return;
> > + if (!pdata->is_omap16xx) {
>
> Is this 'is_omap16xx' really needed here? If the clk_get fails, set
> timer->fclk to NULL, and any other users of fclk should just check the
> validity of timer->fclk.
OK.
>
> > + timer->fclk = clk_get(&timer->pdev->dev, "fck");
> > + if (WARN_ON_ONCE(IS_ERR_OR_NULL(timer->fclk))) {
> > + dev_err(&timer->pdev->dev, ": No fclk handle.\n");
> > + return;
> > + }
> > }
> >
> > - omap_dm_timer_enable(timer);
> > + if (!pdata->is_omap16xx)
> > + omap_dm_timer_enable(timer);
>
> I don't think this if is needed, as runtime PM calls will essentially be
> nops on OMAP1 anyways.
Right, I will remove the check.
>
> > if (pdata->dm_timer_reset)
> > pdata->dm_timer_reset(timer);
> > @@ -292,10 +296,22 @@ EXPORT_SYMBOL_GPL(omap_dm_timer_free);
> >
> > void omap_dm_timer_enable(struct omap_dm_timer *timer)
> > {
> > + struct dmtimer_platform_data *pdata = timer->pdev->dev.platform_data;
> > +
> > if (timer->enabled)
> > return;
> >
> > - clk_enable(timer->fclk);
> > + if (unlikely(pdata->is_early_init)) {
> > + clk_enable(timer->fclk);
> > + timer->enabled = 1;
> > + return;
> > + }
> > +
> > + if (pm_runtime_get_sync(&timer->pdev->dev) < 0) {
> > + dev_err(&timer->pdev->dev, "%s: pm_runtime_get_sync() FAILED\n",
> > + __func__);
> > + return;
> > + }
> >
> > timer->enabled = 1;
> > }
>
> Taking my above suggestion, this can be simplified to:
>
> void omap_dm_timer_enable(struct omap_dm_timer *timer)
> {
> pm_runtime_get_sync(&timer->pdev->dev);
> }
>
> Note that with runtime PM, the ->enabled flag is no longer needed
> either, as you can simply check pm_runtime_suspended(dev) instead.
Sounds good!
>
> > @@ -303,10 +319,22 @@ EXPORT_SYMBOL_GPL(omap_dm_timer_enable);
> >
> > void omap_dm_timer_disable(struct omap_dm_timer *timer)
> > {
> > + struct dmtimer_platform_data *pdata = timer->pdev->dev.platform_data;
> > +
> > if (!timer->enabled)
> > return;
> >
> > - clk_disable(timer->fclk);
> > + if (unlikely(pdata->is_early_init)) {
> > + clk_disable(timer->fclk);
> > + timer->enabled = 0;
> > + return;
> > + }
> > +
> > + if (pm_runtime_put_sync(&timer->pdev->dev) < 0) {
> > + dev_err(&timer->pdev->dev, "%s: pm_runtime_put_sync() FAILED\n",
> > + __func__);
> > + return;
> > + }
> >
> > timer->enabled = 0;
> > }
>
> Likewise, this becomes
>
> void omap_dm_timer_disable(struct omap_dm_timer *timer)
> {
> pm_runtime_put_sync(&timer->pdev->dev);
> }
Yes.
>
> > @@ -425,10 +453,12 @@ int omap_dm_timer_set_source(struct omap_dm_timer
> *timer, int source)
> > if (source < 0 || source >= 3)
> > return -EINVAL;
> >
> > - omap_dm_timer_disable(timer);
> > + if (!pdata->is_omap16xx)
>
> drop the if
Yes.
>
> > + omap_dm_timer_disable(timer);
> > /* change the timer clock source */
> > ret = pdata->set_timer_src(timer->pdev, source);
> > - omap_dm_timer_enable(timer);
> > + if (!pdata->is_omap16xx)
>
> and this one,
>
> and with that, there are no users of is_omap16xx in this patch.
Right!
>
> Kevin
>
>
> > + omap_dm_timer_enable(timer);
> >
> > /*
> > * When the functional clock disappears, too quick writes seem
> > @@ -600,11 +630,26 @@ static int __devinit omap_dm_timer_probe(struct
> platform_device *pdev)
> > return -ENODEV;
> > }
> >
> > + /*
> > + * OMAP2+
> > + * Early timers are already registered and in list.
> > + * What we need to do during second phase of probe
> > + * is to assign the newly allocated/configured pdev
> > + * to timer->pdev. We also call pm_runtime_enable()
> > + * for each device because it could not be called
> > + * during early boot because pm_runtime framework
> > + * was not yet up and running.
> > + */
> > spin_lock_irqsave(&dm_timer_lock, flags);
> > list_for_each_entry(timer, &omap_timer_list, node)
> > if (!pdata->is_early_init && timer->id == pdev->id) {
> > timer->pdev = pdev;
> > spin_unlock_irqrestore(&dm_timer_lock, flags);
> > + pm_runtime_enable(&pdev->dev);
> > + /* update PM runtime for active early timers */
> > + if (timer->reserved)
> > + pm_runtime_get_sync(&pdev->dev);
> > +
> > dev_dbg(&pdev->dev, "Regular Probed\n");
> > return 0;
> > }
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