[Intel-gfx] [PATCH 3/4] drm/i915: Make turning on/off PW1 and Misc I/O part of the init/fini sequences

[Paulo Zanoni]

From: Damien Lespiau <damien.lespiau at intel.com>

Before this patch, we used the intel_display_power_{get,put} functions
to make sure the PW1 and Misc I/O power wells were enabled all the
time while LCPLL was enabled. We called a get() at
intel_ddi_pll_init() when we discovered that LCPLL was enabled, then
we would call put/get at skl_{un,}init_cdclk().

The problem is that skl_uninit_cdclk() is indirectly called by
intel_runtime_suspend(). So it will only release its power well
_after_ we already decided to runtime suspend. But since we only
decide to runtime suspend after all power wells and refcounts are
released, that basically means we will never decide to runtime
suspend.

So what this patch does to fix that problem is move the PW1 + Misc I/O
power well handling out of the runtime PM mechanism: instead of
calling intel_display_power_{get_put} - functions that touch the
refcount -, we'll call the low level intel_power_well_{en,dis}able,
which don't change the refcount. This way, it is now possible for the
refcount to actually reach zero, and we'll now start runtime
suspending/resuming.

v2 (from Paulo):
  - Write a commit message since the original patch left it empty.
  - Rebase after the intel_power_well_{en,dis}able rename.
  - Use lookup_power_well() instead of hardcoded indexes.

Testcase: igt/pm_rpm/rte (and every other rpm test)
Signed-off-by: Damien Lespiau <damien.lespiau at intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
---
 drivers/gpu/drm/i915/intel_ddi.c        |  2 --
 drivers/gpu/drm/i915/intel_display.c    |  5 +++--
 drivers/gpu/drm/i915/intel_drv.h        |  2 ++
 drivers/gpu/drm/i915/intel_runtime_pm.c | 29 +++++++++++++++++++++++++++++
 4 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index 9a40bfb..e629ad3 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -2931,8 +2931,6 @@ void intel_ddi_pll_init(struct drm_device *dev)
 		dev_priv->skl_boot_cdclk = cdclk_freq;
 		if (!(I915_READ(LCPLL1_CTL) & LCPLL_PLL_ENABLE))
 			DRM_ERROR("LCPLL1 is disabled\n");
-		else
-			intel_display_power_get(dev_priv, POWER_DOMAIN_PLLS);
 	} else if (IS_BROXTON(dev)) {
 		broxton_init_cdclk(dev);
 		broxton_ddi_phy_init(dev);
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 43b0f17..34cbe4a 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -5680,7 +5680,8 @@ void skl_uninit_cdclk(struct drm_i915_private *dev_priv)
 	if (wait_for(!(I915_READ(LCPLL1_CTL) & LCPLL_PLL_LOCK), 1))
 		DRM_ERROR("Couldn't disable DPLL0\n");
 
-	intel_display_power_put(dev_priv, POWER_DOMAIN_PLLS);
+	/* disable PG1 and Misc I/O */
+	skl_pw1_misc_io_fini(dev_priv);
 }
 
 void skl_init_cdclk(struct drm_i915_private *dev_priv)
@@ -5693,7 +5694,7 @@ void skl_init_cdclk(struct drm_i915_private *dev_priv)
 	I915_WRITE(HSW_NDE_RSTWRN_OPT, val | RESET_PCH_HANDSHAKE_ENABLE);
 
 	/* enable PG1 and Misc I/O */
-	intel_display_power_get(dev_priv, POWER_DOMAIN_PLLS);
+	skl_pw1_misc_io_init(dev_priv);
 
 	/* DPLL0 already enabed !? */
 	if (I915_READ(LCPLL1_CTL) & LCPLL_PLL_ENABLE) {
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 320c9e6..10e8a2f 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1325,6 +1325,8 @@ void intel_psr_single_frame_update(struct drm_device *dev,
 int intel_power_domains_init(struct drm_i915_private *);
 void intel_power_domains_fini(struct drm_i915_private *);
 void intel_power_domains_init_hw(struct drm_i915_private *dev_priv);
+void skl_pw1_misc_io_init(struct drm_i915_private *dev_priv);
+void skl_pw1_misc_io_fini(struct drm_i915_private *dev_priv);
 void intel_runtime_pm_enable(struct drm_i915_private *dev_priv);
 
 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 821644d..d62b030 100644
--- a/drivers/gpu/drm/i915/intel_runtime_pm.c
+++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
@@ -1505,6 +1505,35 @@ static struct i915_power_well skl_power_wells[] = {
 	},
 };
 
+void skl_pw1_misc_io_init(struct drm_i915_private *dev_priv)
+{
+	struct i915_power_well *well;
+
+	if (!IS_SKYLAKE(dev_priv))
+		return;
+
+	well = lookup_power_well(dev_priv, SKL_DISP_PW_1);
+	intel_power_well_enable(dev_priv, well);
+
+	well = lookup_power_well(dev_priv, SKL_DISP_PW_MISC_IO);
+	intel_power_well_enable(dev_priv, well);
+}
+
+void skl_pw1_misc_io_fini(struct drm_i915_private *dev_priv)
+{
+	struct i915_power_well *well;
+
+	if (!IS_SKYLAKE(dev_priv))
+		return;
+
+	well = lookup_power_well(dev_priv, SKL_DISP_PW_1);
+	intel_power_well_disable(dev_priv, well);
+
+	well = lookup_power_well(dev_priv, SKL_DISP_PW_MISC_IO);
+	intel_power_well_disable(dev_priv, well);
+
+}
+
 static struct i915_power_well bxt_power_wells[] = {
 	{
 		.name = "always-on",
-- 
2.4.6