Re: [PATCH v9 10/11] OMAP: dmtimer: pm_runtime support

[Kevin Hilman <khilman@ti.com>]

Tarun Kanti DebBarma <tarun.kanti@ti.com> 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.
>
> Signed-off-by: Tarun Kanti DebBarma <tarun.kanti@ti.com>
> [p-basak2@ti.com: added pm_runtime logic in probe()]
> Signed-off-by: Partha Basak <p-basak2@ti.com>
> Reviewed-by: Varadarajan, Charulatha <charu@ti.com>
> Acked-by: Cousson, Benoit <b-cousson@ti.com>
> ---
>  arch/arm/plat-omap/dmtimer.c |   60 +++++++++++++++++++++++++++++++++++------
>  1 files changed, 51 insertions(+), 9 deletions(-)
>
> diff --git a/arch/arm/plat-omap/dmtimer.c b/arch/arm/plat-omap/dmtimer.c
> index ed4aada..4de473b 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) {
> +		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);
>  
>  	if (pdata->dm_timer_reset)
>  		pdata->dm_timer_reset(timer);
> @@ -289,10 +293,22 @@ 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;
>  }
> @@ -300,10 +316,22 @@ 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;
>  }
> @@ -422,10 +450,12 @@ 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)
> +		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)
> +		omap_dm_timer_enable(timer);
>  
>  	/*
>  	 * When the functional clock disappears, too quick writes seem
> @@ -597,11 +627,21 @@ static int __devinit omap_dm_timer_probe(struct platform_device *pdev)
>  		return -ENODEV;
>  	}
>  
> +	/* OMAP2+

please fix multi-line comment style

> +	 * 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);
>  			dev_dbg(&pdev->dev, "Regular Probed\n");
>  			return 0;
>  		}

> @@ -652,6 +692,8 @@ static int __devinit omap_dm_timer_probe(struct platform_device *pdev)
>  		pdata->dm_timer_read_reg = omap_dm_timer_read_reg;
>  		pdata->dm_timer_write_reg = omap_dm_timer_write_reg;
>  		pdata->is_early_init = 0;
> +		pm_runtime_enable(&pdev->dev);
> +		dev_dbg(&pdev->dev, " pm_runtime enabled\n");
>  	}
>  
>  	timer->id = pdev->id;

Somehow, you need to also update runtime PM for early timers that were
enabled.  For the PM runtime userspace info to be correct, I think you
also need to do a 'get' here if the timer has also been enabled.

Otherwise, upon boot, checking runtime PM sysfs it looks like no timers
are active, or ever have been active:


/ # cat /sys/devices/platform/omap/omap_timer.*/power/runtime_status            
suspended                                                                       
suspended                                                                       
suspended                                                                       
suspended                                                                       
suspended                                                                       
suspended                                                                       
suspended                                                                       
suspended                                                                       
suspended                                                                       
suspended                                                                       
suspended                                                                       
suspended                                                                       
/ # cat /sys/devices/platform/omap/omap_timer.*/power/runtime_active_time       
0                                                                               
0                                                                               
0                                                                               
0                                                                               
0                                                                               
0                                                                               
0                                                                               
0                                                                               
0                                                                               
0                                                                               
0                                                                               
0                                                                               
/ # 

Kevin