[Intel-gfx] drm/i915/slpc: Add enable_slpc module parameter

[Sagar Arun Kamble]

From: Tom O'Rourke <Tom.O'Rourke at intel.com>

i915.enable_slpc is used to override the default for slpc usage.
The expected values are -1=auto, 0=disabled [default], 1=enabled.

slpc_enable_sanitize() converts i915.enable_slpc to either 0 or 1.
Interpretation of default value is based on HAS_SLPC(), after
slpc_version_check().  This function also enforces the requirement
that guc_submission is required for slpc.

intel_slpc_enabled() returns 1 if SLPC should be used.

v1: Add early call to sanitize enable_slpc in intel_guc_ucode_init
    Remove sanitize enable_slpc call before firmware version check
    is performed. (ChrisW)
    Version check is added in next patch and that will be done as
    part of slpc_enable_sanitize function in the next patch. (Sagar)
    Updated slpc option sanitize function call for platforms without
    GuC support. This was caught by CI BAT.

v2: Changed parameter to dev_priv for HAS_SLPC macro. (David)
    Code indentation based on checkpatch.

Suggested-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
Reviewed-by: David Weinehall <david.weinehall at linux.intel.com>
Signed-off-by: Tom O'Rourke <Tom.O'Rourke at intel.com>
Signed-off-by: Sagar Arun Kamble <sagar.a.kamble at intel.com>
---
 drivers/gpu/drm/i915/i915_params.c      |  6 ++++++
 drivers/gpu/drm/i915/i915_params.h      |  1 +
 drivers/gpu/drm/i915/intel_guc.h        |  6 ++++++
 drivers/gpu/drm/i915/intel_guc_loader.c | 30 ++++++++++++++++++++++++++----
 4 files changed, 39 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c
index 768ad89..72b3097 100644
--- a/drivers/gpu/drm/i915/i915_params.c
+++ b/drivers/gpu/drm/i915/i915_params.c
@@ -36,6 +36,7 @@ struct i915_params i915 __read_mostly = {
 	.enable_dc = -1,
 	.enable_fbc = -1,
 	.enable_execlists = -1,
+	.enable_slpc = 0,
 	.enable_hangcheck = true,
 	.enable_ppgtt = -1,
 	.enable_psr = -1,
@@ -131,6 +132,11 @@ MODULE_PARM_DESC(enable_execlists,
 	"Override execlists usage. "
 	"(-1=auto [default], 0=disabled, 1=enabled)");
 
+module_param_named_unsafe(enable_slpc, i915.enable_slpc, int, 0400);
+MODULE_PARM_DESC(enable_slpc,
+	"Override single-loop-power-controller (slpc) usage. "
+	"(-1=auto, 0=disabled [default], 1=enabled)");
+
 module_param_named_unsafe(enable_psr, i915.enable_psr, int, 0600);
 MODULE_PARM_DESC(enable_psr, "Enable PSR "
 		 "(0=disabled, 1=enabled - link mode chosen per-platform, 2=force link-standby mode, 3=force link-off mode) "
diff --git a/drivers/gpu/drm/i915/i915_params.h b/drivers/gpu/drm/i915/i915_params.h
index 3a0dd78..391c471 100644
--- a/drivers/gpu/drm/i915/i915_params.h
+++ b/drivers/gpu/drm/i915/i915_params.h
@@ -39,6 +39,7 @@ struct i915_params {
 	int enable_fbc;
 	int enable_ppgtt;
 	int enable_execlists;
+	int enable_slpc;
 	int enable_psr;
 	unsigned int preliminary_hw_support;
 	int disable_power_well;
diff --git a/drivers/gpu/drm/i915/intel_guc.h b/drivers/gpu/drm/i915/intel_guc.h
index 9e6b948..bf7624f 100644
--- a/drivers/gpu/drm/i915/intel_guc.h
+++ b/drivers/gpu/drm/i915/intel_guc.h
@@ -146,6 +146,12 @@ struct intel_guc {
 	uint32_t last_seqno[I915_NUM_ENGINES];
 };
 
+static inline int intel_slpc_enabled(void)
+{
+	WARN_ON(i915.enable_slpc < 0);
+	return i915.enable_slpc;
+}
+
 /* intel_guc_loader.c */
 extern void intel_guc_init(struct drm_device *dev);
 extern int intel_guc_setup(struct drm_device *dev);
diff --git a/drivers/gpu/drm/i915/intel_guc_loader.c b/drivers/gpu/drm/i915/intel_guc_loader.c
index 324812d..2dfdb24 100644
--- a/drivers/gpu/drm/i915/intel_guc_loader.c
+++ b/drivers/gpu/drm/i915/intel_guc_loader.c
@@ -144,6 +144,25 @@ static void direct_interrupts_to_guc(struct drm_i915_private *dev_priv)
 	}
 }
 
+static void sanitize_slpc_option(struct drm_i915_private *dev_priv)
+{
+	/* Handle default case */
+	if (i915.enable_slpc < 0)
+		i915.enable_slpc = HAS_SLPC(dev_priv);
+
+	/* slpc requires hardware support and compatible firmware */
+	if (!HAS_SLPC(dev_priv))
+		i915.enable_slpc = 0;
+
+	/* slpc requires guc loaded */
+	if (!i915.enable_guc_loading)
+		i915.enable_slpc = 0;
+
+	/* slpc requires guc submission */
+	if (!i915.enable_guc_submission)
+		i915.enable_slpc = 0;
+}
+
 static u32 get_gttype(struct drm_i915_private *dev_priv)
 {
 	/* XXX: GT type based on PCI device ID? field seems unused by fw */
@@ -728,18 +747,21 @@ void intel_guc_init(struct drm_device *dev)
 	guc_fw->guc_fw_fetch_status = GUC_FIRMWARE_NONE;
 	guc_fw->guc_fw_load_status = GUC_FIRMWARE_NONE;
 
-	/* Early (and silent) return if GuC loading is disabled */
+	/* Return if GuC loading is disabled sanitizing SLPC option */
 	if (!i915.enable_guc_loading)
-		return;
+		goto out;
 	if (fw_path == NULL)
-		return;
+		goto out;
 	if (*fw_path == '\0')
-		return;
+		goto out;
 
 	guc_fw->guc_fw_fetch_status = GUC_FIRMWARE_PENDING;
 	DRM_DEBUG_DRIVER("GuC firmware pending, path %s\n", fw_path);
 	guc_fw_fetch(dev, guc_fw);
 	/* status must now be FAIL or SUCCESS */
+
+out:
+	sanitize_slpc_option(dev_priv);
 }
 
 /**
-- 
1.9.1