drm/i915/skl: Add DC5 Trigger Sequence

Add triggers as per expectations mentioned in gen9_enable_dc5
and gen9_disable_dc5 patch.

Also call POSTING_READ for every write to a register to ensure that
its written immediately.

v1: Remove POSTING_READ calls as they've already been added in previous patches.

v2: Rebase to move all runtime pm specific changes to intel_runtime_pm.c file.

Modified as per review comments from Imre:
1] Change variable name 'dc5_allowed' to 'dc5_enabled' to correspond to relevant
   functions.
2] Move the check dc5_enabled in skl_set_power_well() to disable DC5 into
   gen9_disable_DC5 which is a more appropriate place.
3] Convert checks for 'pm.dc5_enabled' and 'pm.suspended' in skl_set_power_well()
   to warnings. However, removing them for now as they'll be included in a future patch
   asserting DC-state entry/exit criteria.
4] Enable DC5, only when CSR firmware is verified to be loaded. Create new structure
   to track 'enabled' and 'deferred' status of DC5.
5] Ensure runtime PM reference is obtained, if CSR is not loaded, to avoid entering
   runtime-suspend and release it when it's loaded.
6] Protect necessary CSR-related code with locks.
7] Move CSR-loading call to runtime PM initialization, as power domains needed to be
   accessed during deferred DC5-enabling, are not initialized earlier.

v3: Rebase to latest.

Modified as per review comments from Imre:
1] Use blocking wait for CSR-loading to finish to enable DC5  for simplicity, instead of
   deferring enabling DC5 until CSR is loaded.
2] Obtain runtime PM reference during CSR-loading initialization itself as deferred DC5-
   enabling is removed and release it at the end of CSR-loading functionality.
3] Revert calling CSR-loading functionality to the beginning of i915 driver-load
   functionality to avoid any delay in loading.
4] Define another variable to track whether CSR-loading failed and use it to avoid enabling
   DC5 if it's true.
5] Define CSR-load-status accessor functions for use later.

v4:
1] Disable DC5 before enabling PG2 instead of after it.
2] DC5 was being mistaken enabled even when CSR-loading timed-out. Fix that.
3] Enable DC5-related functionality using a macro.
4] Remove dc5_enabled tracking variable and its use as it's not needed now.

v5:
1] Mark CSR failed to load where necessary in finish_csr_load function.
2] Use mutex-protected accessor function to check if CSR loaded instead of directly
   accessing the variable.
3] Prefix csr_load_status_get/set function names with intel_.

v6: rebase to latest.
v7: Rebase on top of nightly (Damien)
v8: Squashed the patch from Imre - added csr helper pointers to simplify the code. (Imre)
v9: After adding dmc ver 1.0 support rebased on top of nightly. (Animesh)
v10: Added a enum for different csr states, suggested by Imre. (Animesh)

v11: Based on review comments from Imre, Damien and Daniel following changes done
- enum name chnaged to csr_state (singular form).
- FW_UNINITIALIZED used as zeroth element in enum csr_state.
- Prototype changed for helper function(set/get csr status), using enum csr_state instead of bool.

v12: Based on review comment from Imre, introduced bool fw_loaded local to finish_csr_load() which helps
calling once to set the csr status. The same flag used to fail RPM if find any issue during
firmware loading.

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: Imre Deak <imre.deak@intel.com>
Signed-off-by: Animesh Manna <animesh.manna@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.h

@@ -669,6 +669,12 @@ struct intel_uncore {
 #define for_each_fw_domain(domain__, dev_priv__, i__) \
 	for_each_fw_domain_mask(domain__, FORCEWAKE_ALL, dev_priv__, i__)
 
+enum csr_state {
+	FW_UNINITIALIZED = 0,
+	FW_LOADED,
+	FW_FAILED
+};
+
 struct intel_csr {
 	const char *fw_path;
 	__be32 *dmc_payload;
@@ -676,6 +682,7 @@ struct intel_csr {
 	uint32_t mmio_count;
 	uint32_t mmioaddr[8];
 	uint32_t mmiodata[8];
+	enum csr_state state;
 };
 
 #define DEV_INFO_FOR_EACH_FLAG(func, sep) \

drivers/gpu/drm/i915/intel_csr.c

@@ -183,6 +183,25 @@ static char intel_get_substepping(struct drm_device *dev)
 		return -ENODATA;
 }
 
+enum csr_state intel_csr_load_status_get(struct drm_i915_private *dev_priv)
+{
+	enum csr_state state;
+
+	mutex_lock(&dev_priv->csr_lock);
+	state = dev_priv->csr.state;
+	mutex_unlock(&dev_priv->csr_lock);
+
+	return state;
+}
+
+void intel_csr_load_status_set(struct drm_i915_private *dev_priv,
+			enum csr_state state)
+{
+	mutex_lock(&dev_priv->csr_lock);
+	dev_priv->csr.state = state;
+	mutex_unlock(&dev_priv->csr_lock);
+}
+
 void intel_csr_load_program(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
@@ -204,6 +223,8 @@ void intel_csr_load_program(struct drm_device *dev)
 		I915_WRITE(dev_priv->csr.mmioaddr[i],
 			dev_priv->csr.mmiodata[i]);
 	}
+
+	dev_priv->csr.state = FW_LOADED;
 	mutex_unlock(&dev_priv->csr_lock);
 }
 
@@ -220,6 +241,7 @@ static void finish_csr_load(const struct firmware *fw, void *context)
 	uint32_t dmc_offset = CSR_DEFAULT_FW_OFFSET, readcount = 0, nbytes;
 	uint32_t i;
 	__be32 *dmc_payload;
+	bool fw_loaded = false;
 
 	if (!fw) {
 		i915_firmware_load_error_print(csr->fw_path, 0);
@@ -326,7 +348,14 @@ static void finish_csr_load(const struct firmware *fw, void *context)
 
 	/* load csr program during system boot, as needed for DC states */
 	intel_csr_load_program(dev);
+	fw_loaded = true;
+
 out:
+	if (fw_loaded)
+		intel_runtime_pm_put(dev_priv);
+	else
+		intel_csr_load_status_set(dev_priv, FW_FAILED);
+
 	release_firmware(fw);
 }
 
@@ -343,17 +372,25 @@ void intel_csr_ucode_init(struct drm_device *dev)
 		csr->fw_path = I915_CSR_SKL;
 	else {
 		DRM_ERROR("Unexpected: no known CSR firmware for platform\n");
+		intel_csr_load_status_set(dev_priv, FW_FAILED);
 		return;
 	}
 
+	/*
+	 * Obtain a runtime pm reference, until CSR is loaded,
+	 * to avoid entering runtime-suspend.
+	 */
+	intel_runtime_pm_get(dev_priv);
+
 	/* CSR supported for platform, load firmware */
 	ret = request_firmware_nowait(THIS_MODULE, true, csr->fw_path,
 				&dev_priv->dev->pdev->dev,
 				GFP_KERNEL, dev_priv,
 				finish_csr_load);
-	if (ret)
+	if (ret) {
 		i915_firmware_load_error_print(csr->fw_path, ret);
-
+		intel_csr_load_status_set(dev_priv, FW_FAILED);
+	}
 }
 
 void intel_csr_ucode_fini(struct drm_device *dev)
@@ -363,5 +400,6 @@ void intel_csr_ucode_fini(struct drm_device *dev)
 	if (!HAS_CSR(dev))
 		return;
 
+	intel_csr_load_status_set(dev_priv, FW_FAILED);
 	kfree(dev_priv->csr.dmc_payload);
 }

drivers/gpu/drm/i915/intel_drv.h

@@ -1155,6 +1155,9 @@ u32 skl_plane_ctl_rotation(unsigned int rotation);
 
 /* intel_csr.c */
 void intel_csr_ucode_init(struct drm_device *dev);
+enum csr_state intel_csr_load_status_get(struct drm_i915_private *dev_priv);
+void intel_csr_load_status_set(struct drm_i915_private *dev_priv,
+					enum csr_state state);
 void intel_csr_load_program(struct drm_device *dev);
 void intel_csr_ucode_fini(struct drm_device *dev);
 

drivers/gpu/drm/i915/intel_runtime_pm.c

@@ -49,6 +49,8 @@
  * present for a given platform.
  */
 
+#define GEN9_ENABLE_DC5(dev) (IS_SKYLAKE(dev))
+
 #define for_each_power_well(i, power_well, domain_mask, power_domains)	\
 	for (i = 0;							\
 	     i < (power_domains)->power_well_count &&			\
@@ -417,9 +419,20 @@ void bxt_disable_dc9(struct drm_i915_private *dev_priv)
 	POSTING_READ(DC_STATE_EN);
 }
 
+static void gen9_enable_dc5(struct drm_i915_private *dev_priv)
+{
+	/* TODO: Implementation to be done. */
+}
+
+static void gen9_disable_dc5(struct drm_i915_private *dev_priv)
+{
+	/* TODO: Implementation to be done. */
+}
+
 static void skl_set_power_well(struct drm_i915_private *dev_priv,
 			struct i915_power_well *power_well, bool enable)
 {
+	struct drm_device *dev = dev_priv->dev;
 	uint32_t tmp, fuse_status;
 	uint32_t req_mask, state_mask;
 	bool is_enabled, enable_requested, check_fuse_status = false;
@@ -459,6 +472,13 @@ static void skl_set_power_well(struct drm_i915_private *dev_priv,
 
 	if (enable) {
 		if (!enable_requested) {
+			WARN((tmp & state_mask) &&
+				!I915_READ(HSW_PWR_WELL_BIOS),
+				"Invalid for power well status to be enabled, unless done by the BIOS, \
+				when request is to disable!\n");
+			if (GEN9_ENABLE_DC5(dev) &&
+				power_well->data == SKL_DISP_PW_2)
+				gen9_disable_dc5(dev_priv);
 			I915_WRITE(HSW_PWR_WELL_DRIVER, tmp | req_mask);
 		}
 
@@ -475,6 +495,19 @@ static void skl_set_power_well(struct drm_i915_private *dev_priv,
 			I915_WRITE(HSW_PWR_WELL_DRIVER,	tmp & ~req_mask);
 			POSTING_READ(HSW_PWR_WELL_DRIVER);
 			DRM_DEBUG_KMS("Disabling %s\n", power_well->name);
+
+			if (GEN9_ENABLE_DC5(dev) &&
+				power_well->data == SKL_DISP_PW_2) {
+				enum csr_state state;
+
+				wait_for((state = intel_csr_load_status_get(dev_priv)) !=
+						FW_UNINITIALIZED, 1000);
+				if (state != FW_LOADED)
+					DRM_ERROR("CSR firmware not ready (%d)\n",
+							state);
+				else
+					gen9_enable_dc5(dev_priv);
+			}
 		}
 	}