Re: [PATCH v2 13/13] drm/i915: Acquire P-Unit access when modifying P-Unit settings

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Hi,

On 01/27/2017 02:51 PM, Ville Syrjälä wrote:

On Mon, Jan 23, 2017 at 10:09:58PM +0100, Hans de Goede wrote:

Make sure the P-Unit or the PMIC i2c bus is not in use when we send a
request to the P-Unit by calling iosf_mbi_punit_acquire() / _release()
around P-Unit write accesses.


Can't we just stuff the calls into the actual punit write function
rather than sprinkling them all over the place?


punit access is acquired across sections like this:

        iosf_mbi_punit_acquire();

        val = vlv_punit_read(dev_priv, PUNIT_REG_DSPFREQ);
        val &= ~DSPFREQGUAR_MASK;
        val |= (cmd << DSPFREQGUAR_SHIFT);
        vlv_punit_write(dev_priv, PUNIT_REG_DSPFREQ, val);
        if (wait_for((vlv_punit_read(dev_priv, PUNIT_REG_DSPFREQ) &
                      DSPFREQSTAT_MASK) == (cmd << DSPFREQSTAT_SHIFT),
                     50)) {
                DRM_ERROR("timed out waiting for CDclk change\n");
        }
        iosf_mbi_punit_release();

Where we want to wait for the requested change to have taken
effect before releasing the punit.



+ a comment would be nice why it's there.


I will add comments to the acquire calls.


Do we need a kconfig select/depends on the iosf_mbi thing? Or some
ifdefs?


No, the iosf_mbi header defines empty inline versions of
iosf_mbi_punit_acquire / _release if IOSF_MBI is disabled,
this does mean that iosf_mbi must be builtin if the i915
driver is. I'll add:

	depends on DRM_I915=IOSF_MBI || IOSF_MBI=y

To the i915 Kconfig to enforce this.

Regards,

Hans






BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=155241
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
Tested-by: tagorereddy <tagore.chandan@xxxxxxxxx>
---
Changes in v2:
-Spelling: P-Unit, PMIC
-Adjust for iosf_mbi_punit_lock/_unlock to _acquire/_release rename
---
 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 5604701..13e5152 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)
 {
@@ -6421,6 +6422,8 @@ static void valleyview_set_cdclk(struct drm_device *dev, int cdclk)
 		cmd = 0;

 	mutex_lock(&dev_priv->rps.hw_lock);
+	iosf_mbi_punit_acquire();
+
 	val = vlv_punit_read(dev_priv, PUNIT_REG_DSPFREQ);
 	val &= ~DSPFREQGUAR_MASK;
 	val |= (cmd << DSPFREQGUAR_SHIFT);
@@ -6430,6 +6433,7 @@ static void valleyview_set_cdclk(struct drm_device *dev, int cdclk)
 		     50)) {
 		DRM_ERROR("timed out waiting for CDclk change\n");
 	}
+	iosf_mbi_punit_release();
 	mutex_unlock(&dev_priv->rps.hw_lock);

 	mutex_lock(&dev_priv->sb_lock);
@@ -6497,6 +6501,7 @@ 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_acquire();
 	val = vlv_punit_read(dev_priv, PUNIT_REG_DSPFREQ);
 	val &= ~DSPFREQGUAR_MASK_CHV;
 	val |= (cmd << DSPFREQGUAR_SHIFT_CHV);
@@ -6506,6 +6511,7 @@ static void cherryview_set_cdclk(struct drm_device *dev, int cdclk)
 		     50)) {
 		DRM_ERROR("timed out waiting for CDclk change\n");
 	}
+	iosf_mbi_punit_release();
 	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 249623d..adff84a 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_acquire();

 	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_release();
 	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_acquire();

 	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_release();
 	mutex_unlock(&dev_priv->rps.hw_lock);
 }

@@ -4553,6 +4558,7 @@ 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_acquire();

 		val = vlv_punit_read(dev_priv, PUNIT_REG_DSPFREQ);
 		if (val & DSP_MAXFIFO_PM5_ENABLE)
@@ -4582,6 +4588,7 @@ void vlv_wm_get_hw_state(struct drm_device *dev)
 				wm->level = VLV_WM_LEVEL_DDR_DVFS;
 		}

+		iosf_mbi_punit_release();
 		mutex_unlock(&dev_priv->rps.hw_lock);
 	}

@@ -4988,7 +4995,9 @@ 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_acquire();
 		vlv_punit_write(dev_priv, PUNIT_REG_GPU_FREQ_REQ, val);
+		iosf_mbi_punit_release();
 		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..e66bcc8 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_acquire();
+
 	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_release();
+
 #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_acquire();
+
 	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_release();
+
 #undef COND

 out:
--
2.9.3



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