Re: [PATCH 7/7] drm/i915: Take punit lock when modifying punit settings

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

On Sun, 2017-01-08 at 14:44 +0100, Hans de Goede wrote:
> Make sure the punit i2c bus is not in use when we send a request to
> the punit by calling iosf_mbi_punit_lock() / iosf_mbi_punit_unlock()
> around punit write accesses.
> 

But should not i915 drm eventually share the same iosf_mbi driver?
Currently what you are doing you create notifier and all that not-best-
ever stuff due to having two accessors to IOSF MB. If we have only one
driver which i915 will not ignore you don't need to create such things.

That's what I was trying to imply when commenting one of the patch in
previous series.


> BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=155241
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> Tested-by: tagorereddy <tagore.chandan@gmail.com>
> ---
>  drivers/gpu/drm/i915/intel_display.c    | 6 ++++++
>  drivers/gpu/drm/i915/intel_pm.c         | 9 +++++++++
>  drivers/gpu/drm/i915/intel_runtime_pm.c | 9 +++++++++
>  3 files changed, 24 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/intel_display.c
> b/drivers/gpu/drm/i915/intel_display.c
> index fec8eb3..b8be6ea 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -47,6 +47,7 @@
>  #include <drm/drm_rect.h>
>  #include <linux/dma_remapping.h>
>  #include <linux/reservation.h>
> +#include <asm/iosf_mbi.h>
>  
>  static bool is_mmio_work(struct intel_flip_work *work)
>  {
> @@ -6423,6 +6424,8 @@ static void valleyview_set_cdclk(struct
> drm_device *dev, int cdclk)
>  		cmd = 0;
>  
>  	mutex_lock(&dev_priv->rps.hw_lock);
> +	iosf_mbi_punit_lock();
> +
>  	val = vlv_punit_read(dev_priv, PUNIT_REG_DSPFREQ);
>  	val &= ~DSPFREQGUAR_MASK;
>  	val |= (cmd << DSPFREQGUAR_SHIFT);
> @@ -6432,6 +6435,7 @@ static void valleyview_set_cdclk(struct
> drm_device *dev, int cdclk)
>  		     50)) {
>  		DRM_ERROR("timed out waiting for CDclk change\n");
>  	}
> +	iosf_mbi_punit_unlock();
>  	mutex_unlock(&dev_priv->rps.hw_lock);
>  
>  	mutex_lock(&dev_priv->sb_lock);
> @@ -6499,6 +6503,7 @@ static void cherryview_set_cdclk(struct
> drm_device *dev, int cdclk)
>  	cmd = DIV_ROUND_CLOSEST(dev_priv->hpll_freq << 1, cdclk) - 1;
>  
>  	mutex_lock(&dev_priv->rps.hw_lock);
> +	iosf_mbi_punit_lock();
>  	val = vlv_punit_read(dev_priv, PUNIT_REG_DSPFREQ);
>  	val &= ~DSPFREQGUAR_MASK_CHV;
>  	val |= (cmd << DSPFREQGUAR_SHIFT_CHV);
> @@ -6508,6 +6513,7 @@ static void cherryview_set_cdclk(struct
> drm_device *dev, int cdclk)
>  		     50)) {
>  		DRM_ERROR("timed out waiting for CDclk change\n");
>  	}
> +	iosf_mbi_punit_unlock();
>  	mutex_unlock(&dev_priv->rps.hw_lock);
>  
>  	intel_update_cdclk(dev_priv);
> diff --git a/drivers/gpu/drm/i915/intel_pm.c
> b/drivers/gpu/drm/i915/intel_pm.c
> index 4b12637..0d55b61 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -32,6 +32,7 @@
>  #include "../../../platform/x86/intel_ips.h"
>  #include <linux/module.h>
>  #include <drm/drm_atomic_helper.h>
> +#include <asm/iosf_mbi.h>
>  
>  /**
>   * DOC: RC6
> @@ -276,6 +277,7 @@ static void chv_set_memory_dvfs(struct
> drm_i915_private *dev_priv, bool enable)
>  	u32 val;
>  
>  	mutex_lock(&dev_priv->rps.hw_lock);
> +	iosf_mbi_punit_lock();
>  
>  	val = vlv_punit_read(dev_priv, PUNIT_REG_DDR_SETUP2);
>  	if (enable)
> @@ -290,6 +292,7 @@ static void chv_set_memory_dvfs(struct
> drm_i915_private *dev_priv, bool enable)
>  		      FORCE_DDR_FREQ_REQ_ACK) == 0, 3))
>  		DRM_ERROR("timed out waiting for Punit DDR DVFS
> request\n");
>  
> +	iosf_mbi_punit_unlock();
>  	mutex_unlock(&dev_priv->rps.hw_lock);
>  }
>  
> @@ -298,6 +301,7 @@ static void chv_set_memory_pm5(struct
> drm_i915_private *dev_priv, bool enable)
>  	u32 val;
>  
>  	mutex_lock(&dev_priv->rps.hw_lock);
> +	iosf_mbi_punit_lock();
>  
>  	val = vlv_punit_read(dev_priv, PUNIT_REG_DSPFREQ);
>  	if (enable)
> @@ -306,6 +310,7 @@ static void chv_set_memory_pm5(struct
> drm_i915_private *dev_priv, bool enable)
>  		val &= ~DSP_MAXFIFO_PM5_ENABLE;
>  	vlv_punit_write(dev_priv, PUNIT_REG_DSPFREQ, val);
>  
> +	iosf_mbi_punit_unlock();
>  	mutex_unlock(&dev_priv->rps.hw_lock);
>  }
>  
> @@ -4546,6 +4551,7 @@ void vlv_wm_get_hw_state(struct drm_device *dev)
>  
>  	if (IS_CHERRYVIEW(dev_priv)) {
>  		mutex_lock(&dev_priv->rps.hw_lock);
> +		iosf_mbi_punit_lock();
>  
>  		val = vlv_punit_read(dev_priv, PUNIT_REG_DSPFREQ);
>  		if (val & DSP_MAXFIFO_PM5_ENABLE)
> @@ -4575,6 +4581,7 @@ void vlv_wm_get_hw_state(struct drm_device *dev)
>  				wm->level = VLV_WM_LEVEL_DDR_DVFS;
>  		}
>  
> +		iosf_mbi_punit_unlock();
>  		mutex_unlock(&dev_priv->rps.hw_lock);
>  	}
>  
> @@ -4981,7 +4988,9 @@ static void valleyview_set_rps(struct
> drm_i915_private *dev_priv, u8 val)
>  	I915_WRITE(GEN6_PMINTRMSK, gen6_rps_pm_mask(dev_priv, val));
>  
>  	if (val != dev_priv->rps.cur_freq) {
> +		iosf_mbi_punit_lock();
>  		vlv_punit_write(dev_priv, PUNIT_REG_GPU_FREQ_REQ,
> val);
> +		iosf_mbi_punit_unlock();
>  		if (!IS_CHERRYVIEW(dev_priv))
>  			gen6_set_rps_thresholds(dev_priv, val);
>  	}
> diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c
> b/drivers/gpu/drm/i915/intel_runtime_pm.c
> index c0b7e95..17922ae 100644
> --- a/drivers/gpu/drm/i915/intel_runtime_pm.c
> +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
> @@ -28,6 +28,7 @@
>  
>  #include <linux/pm_runtime.h>
>  #include <linux/vgaarb.h>
> +#include <asm/iosf_mbi.h>
>  
>  #include "i915_drv.h"
>  #include "intel_drv.h"
> @@ -1027,6 +1028,8 @@ static void vlv_set_power_well(struct
> drm_i915_private *dev_priv,
>  	if (COND)
>  		goto out;
>  
> +	iosf_mbi_punit_lock();
> +
>  	ctrl = vlv_punit_read(dev_priv, PUNIT_REG_PWRGT_CTRL);
>  	ctrl &= ~mask;
>  	ctrl |= state;
> @@ -1037,6 +1040,8 @@ static void vlv_set_power_well(struct
> drm_i915_private *dev_priv,
>  			  state,
>  			  vlv_punit_read(dev_priv,
> PUNIT_REG_PWRGT_CTRL));
>  
> +	iosf_mbi_punit_unlock();
> +
>  #undef COND
>  
>  out:
> @@ -1643,6 +1648,8 @@ static void chv_set_pipe_power_well(struct
> drm_i915_private *dev_priv,
>  	if (COND)
>  		goto out;
>  
> +	iosf_mbi_punit_lock();
> +
>  	ctrl = vlv_punit_read(dev_priv, PUNIT_REG_DSPFREQ);
>  	ctrl &= ~DP_SSC_MASK(pipe);
>  	ctrl |= enable ? DP_SSC_PWR_ON(pipe) : DP_SSC_PWR_GATE(pipe);
> @@ -1653,6 +1660,8 @@ static void chv_set_pipe_power_well(struct
> drm_i915_private *dev_priv,
>  			  state,
>  			  vlv_punit_read(dev_priv,
> PUNIT_REG_DSPFREQ));
>  
> +	iosf_mbi_punit_unlock();
> +
>  #undef COND
>  
>  out:

-- 
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy
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