Re: [PATCH 4/8] drm/i915/skl: Assert the requirements to enter or exit DC5.

[Imre Deak <imre.deak@intel.com>]

On Wed, 2015-04-01 at 16:22 +0530, Animesh Manna wrote:
> From: Suketu Shah <suketu.j.shah@intel.com>
> 
> Warn if the conditions to enter or exit DC5 are not satisfied such
> as support for runtime PM, state of power well, CSR loading etc.
> 
> v2: Removed camelcase in functions and variables.
> 
> v3: Do some minimal check to assert if CSR program is not loaded.
> 
> v4:
> 1] Used an appropriate function lookup_power_well() to identify power well,
> instead of using a magic number which can change in future.
> 2] Split the conditions further in assert_can_enable_DC5() and added more checks.
> 3] Removed all WARNs from assert_can_disable_DC5 as they were unnecessary and added two
>    new ones.
> 4] Changed variable names as updated in earlier patches.
> 
> v5:
> 1] Change lookup_power_well function to take an int power well id.
> 2] Define a new intel_display_power_well_is_enabled helper function to check whether a
>    particular power well is enabled.
> 3] Use CSR-related mutex in assert_csr_loaded function.
> 
> v6: Remove use of dc5_enabled variable as it's no longer needed.
> 
> v7:
> 1] Rebase to latest.
> 2] Move all DC5-related functions from intel_display.c to intel_runtime_pm.c.
> 
> v8: After adding dmc ver 1.0 support rebased on top of nightly. (Animesh)
> 
> Issue: VIZ-2819
> Signed-off-by: A.Sunil Kamath <sunil.kamath@intel.com>
> Signed-off-by: Suketu Shah <suketu.j.shah@intel.com>
> Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
> Signed-off-by: Animesh Manna <animesh.manna@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_drv.h        |  2 ++
>  drivers/gpu/drm/i915/intel_runtime_pm.c | 61 ++++++++++++++++++++++++++++++---
>  2 files changed, 58 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index 39cb2dc..9aae624 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -1232,6 +1232,8 @@ void intel_power_domains_fini(struct drm_i915_private *);
>  void intel_power_domains_init_hw(struct drm_i915_private *dev_priv);
>  void intel_runtime_pm_enable(struct drm_i915_private *dev_priv);
>  
> +bool intel_display_power_well_is_enabled(struct drm_i915_private *dev_priv,
> +				    int power_well_id);

I haven't seen this being used outside of intel_runtime_pm, so no need
to export it.

>  bool intel_display_power_is_enabled(struct drm_i915_private *dev_priv,
>  				    enum intel_display_power_domain domain);
>  bool __intel_display_power_is_enabled(struct drm_i915_private *dev_priv,
> diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
> index 8b917e2..f62d42b 100644
> --- a/drivers/gpu/drm/i915/intel_runtime_pm.c
> +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
> @@ -335,12 +335,52 @@ static void gen9_set_dc_state_debugmask_memory_up(
>  	}
>  }
>  
> -static void gen9_enable_dc5(struct drm_i915_private *dev_priv)
> +static void assert_csr_loaded(struct drm_i915_private *dev_priv)
> +{
> +	mutex_lock(&dev_priv->csr_lock);

No point in taking the lock here.

> +
> +	WARN(!dev_priv->csr.loaded, "CSR is not loaded.\n");
> +	WARN(!I915_READ(CSR_PROGRAM_BASE),
> +				"CSR program storage start is NULL\n");
> +	WARN(!I915_READ(CSR_SSP_BASE), "CSR SSP Base Not fine\n");
> +	WARN(!I915_READ(CSR_HTP_SKL), "CSR HTP Not fine\n");
> +
> +	mutex_unlock(&dev_priv->csr_lock);
> +}
> +
> +static void assert_can_enable_dc5(struct drm_i915_private *dev_priv)
>  {
>  	struct drm_device *dev = dev_priv->dev;
> +	bool pg2_enabled = intel_display_power_well_is_enabled(dev_priv,
> +					SKL_DISP_PW_2);
> +
> +	WARN(!IS_SKYLAKE(dev), "Platform doesn't support DC5.\n");
> +	WARN(!HAS_RUNTIME_PM(dev), "Runtime PM not enabled.\n");
> +	WARN(pg2_enabled, "PG2 not disabled to enable DC5.\n");
> +
> +	WARN((I915_READ(DC_STATE_EN) & DC_STATE_EN_UPTO_DC5),
> +				"DC5 already programmed to be enabled.\n");
> +	WARN(dev_priv->pm.suspended,
> +		"DC5 cannot be enabled, if platform is runtime-suspended.\n");
> +
> +	assert_csr_loaded(dev_priv);
> +}
> +
> +static void assert_can_disable_dc5(struct drm_i915_private *dev_priv)
> +{
> +	bool pg2_enabled = intel_display_power_well_is_enabled(dev_priv,
> +					SKL_DISP_PW_2);
> +
> +	WARN(!pg2_enabled, "PG2 not enabled to disable DC5.\n");
> +	WARN(dev_priv->pm.suspended,
> +		"Disabling of DC5 while platform is runtime-suspended should never happen.\n");
> +}
> +
> +static void gen9_enable_dc5(struct drm_i915_private *dev_priv)
> +{
>  	uint32_t val;
>  
> -	WARN_ON(!IS_GEN9(dev));
> +	assert_can_enable_dc5(dev_priv);
>  
>  	DRM_DEBUG_KMS("Enabling DC5\n");
>  
> @@ -355,10 +395,9 @@ static void gen9_enable_dc5(struct drm_i915_private *dev_priv)
>  
>  static void gen9_disable_dc5(struct drm_i915_private *dev_priv)
>  {
> -	struct drm_device *dev = dev_priv->dev;
>  	uint32_t val;
>  
> -	WARN_ON(!IS_GEN9(dev));
> +	assert_can_disable_dc5(dev_priv);
>  
>  	DRM_DEBUG_KMS("Disabling DC5\n");
>  
> @@ -1326,7 +1365,7 @@ static struct i915_power_well chv_power_wells[] = {
>  };
>  
>  static struct i915_power_well *lookup_power_well(struct drm_i915_private *dev_priv,
> -						 enum punit_power_well power_well_id)
> +						 int power_well_id)

power_well_id can refer to some other power well besides one in punit,
so we should keep this as int.

>  {
>  	struct i915_power_domains *power_domains = &dev_priv->power_domains;
>  	struct i915_power_well *power_well;
> @@ -1340,6 +1379,18 @@ static struct i915_power_well *lookup_power_well(struct drm_i915_private *dev_pr
>  	return NULL;
>  }
>  
> +bool intel_display_power_well_is_enabled(struct drm_i915_private *dev_priv,
> +				    int power_well_id)
> +{
> +	struct i915_power_well *power_well = NULL;

No need to initialize this.

With the above fixed this is:
Reviewed-by: Imre Deak <imre.deak@intel.com>

> +	bool ret;
> +
> +	power_well = lookup_power_well(dev_priv, power_well_id);
> +	ret = power_well->ops->is_enabled(dev_priv, power_well);
> +
> +	return ret;
> +}
> +
>  static struct i915_power_well skl_power_wells[] = {
>  	{
>  		.name = "always-on",


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