[Intel-gfx] drm/i915/slpc: Update current requested frequency

[Chris Wilson]

On Sat, Aug 20, 2016 at 10:39:10AM +0530, Sagar Arun Kamble wrote:
> From: Tom O'Rourke <Tom.O'Rourke at intel.com>
> 
> When SLPC is controlling requested frequency, the rps.cur_freq
> value is not used to make the frequency request.
> 
> Before using rps.cur_freq in sysfs or debugfs, read
> requested frequency from register to get the value
> most recently requested by SLPC firmware.
> 
> v2: replace HAS_SLPC with intel_slpc_active (Paulo)
> v3: Avoid magic numbers (Nick)
>     Use a function for repeated code (Jon)
> 
> Signed-off-by: Tom O'Rourke <Tom.O'Rourke at intel.com>
> Signed-off-by: Sagar Arun Kamble <sagar.a.kamble at intel.com>
> ---
>  drivers/gpu/drm/i915/i915_debugfs.c | 6 ++++++
>  drivers/gpu/drm/i915/i915_drv.h     | 5 +++++
>  drivers/gpu/drm/i915/i915_reg.h     | 1 +
>  drivers/gpu/drm/i915/i915_sysfs.c   | 8 ++++++++
>  4 files changed, 20 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
> index 01ae5ee..a99a3f6 100644
> --- a/drivers/gpu/drm/i915/i915_debugfs.c
> +++ b/drivers/gpu/drm/i915/i915_debugfs.c
> @@ -1110,6 +1110,9 @@ static int i915_frequency_info(struct seq_file *m, void *unused)
>  
>  	intel_runtime_pm_get(dev_priv);
>  
> +	if (intel_slpc_active(dev_priv))
> +		dev_priv->rps.cur_freq = gen9_read_requested_freq(dev_priv);

Do not alter cur_freq here, as we print out RPNSWEQ and updating
cur_freq defeats the purpose of showing the internal value vs the hw
value.

Instead add "SLPC active" to the output.

> +
>  	if (IS_GEN5(dev)) {
>  		u16 rgvswctl = I915_READ16(MEMSWCTL);
>  		u16 rgvstat = I915_READ16(MEMSTAT_ILK);
> @@ -2372,6 +2375,9 @@ static int i915_rps_boost_info(struct seq_file *m, void *data)
>  	struct drm_i915_private *dev_priv = to_i915(dev);
>  	struct drm_file *file;

if (intel_slpc_active(dev_priv))
	return -ENODEV;
>  
> +	if (intel_slpc_active(dev_priv))
> +		dev_priv->rps.cur_freq = gen9_read_requested_freq(dev_priv);
> +
>  	seq_printf(m, "RPS enabled? %d\n", dev_priv->rps.enabled);
>  	seq_printf(m, "GPU busy? %s [%x]\n",
>  		   yesno(dev_priv->gt.awake), dev_priv->gt.active_engines);
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 764fad0..fcd2e98 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -3913,4 +3913,9 @@ bool i915_memcpy_from_wc(void *dst, const void *src, unsigned long len);
>  	__T;								\
>  })
>  
> +static inline u8 gen9_read_requested_freq(struct drm_i915_private *dev_priv)
> +{
> +	return (u8) GEN9_GET_FREQUENCY(I915_READ(GEN6_RPNSWREQ));
> +}

Move to sysfs and look carefully at what you wrote.

>  #endif
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index d4adf28..1654245 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -6997,6 +6997,7 @@ enum {
>  #define   GEN6_FREQUENCY(x)			((x)<<25)
>  #define   HSW_FREQUENCY(x)			((x)<<24)
>  #define   GEN9_FREQUENCY(x)			((x)<<23)
> +#define   GEN9_GET_FREQUENCY(x)			((x)>>23)
>  #define   GEN6_OFFSET(x)			((x)<<19)
>  #define   GEN6_AGGRESSIVE_TURBO			(0<<15)
>  #define GEN6_RC_VIDEO_FREQ			_MMIO(0xA00C)
> diff --git a/drivers/gpu/drm/i915/i915_sysfs.c b/drivers/gpu/drm/i915/i915_sysfs.c
> index f1ffde7..8404816 100644
> --- a/drivers/gpu/drm/i915/i915_sysfs.c
> +++ b/drivers/gpu/drm/i915/i915_sysfs.c
> @@ -302,6 +302,14 @@ static ssize_t gt_cur_freq_mhz_show(struct device *kdev,
>  	struct drm_device *dev = minor->dev;
>  	struct drm_i915_private *dev_priv = to_i915(dev);
>  
> +	if (intel_slpc_active(dev_priv)) {
> +		intel_runtime_pm_get(dev_priv);

Use get_if_in_use and just show a stale value when the hw is asleep
would be my preference. cur_freq is just our request, act_freq is the
actual hw value.

> +		mutex_lock(&dev_priv->rps.hw_lock);

Useless mutex.

> +		dev_priv->rps.cur_freq = gen9_read_requested_freq(dev_priv);
> +		mutex_unlock(&dev_priv->rps.hw_lock);
> +		intel_runtime_pm_put(dev_priv);
> +	}
> +
>  	return snprintf(buf, PAGE_SIZE, "%d\n",
>  			intel_gpu_freq(dev_priv,
>  				       dev_priv->rps.cur_freq));
> -- 
> 1.9.1
> 
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-- 
Chris Wilson, Intel Open Source Technology Centre