[PATCH 04/25] 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.

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.

v3: Rebase.

v4: Moved sanitization of SLPC option post GuC load.

v5: Removed function intel_slpc_enabled. Planning to rely only on
    kernel parameter. Moved sanitization prior to GuC load to use the
    parameter during SLPC state setup during to GuC load. (Sagar)

v6: Commit message update. Rebase.

Suggested-by: Paulo Zanoni <paulo.r.zanoni at 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_loader.c | 24 +++++++++++++++++++++---
 3 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c
index 2e9645e..750c398 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,
@@ -140,6 +141,11 @@ struct i915_params i915 __read_mostly = {
 	"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 55d47ee..cca512e 100644
--- a/drivers/gpu/drm/i915/i915_params.h
+++ b/drivers/gpu/drm/i915/i915_params.h
@@ -40,6 +40,7 @@
 	func(int, enable_ppgtt); \
 	func(int, enable_execlists); \
 	func(int, enable_psr); \
+	func(int, enable_slpc); \
 	func(int, disable_power_well); \
 	func(int, enable_ips); \
 	func(int, invert_brightness); \
diff --git a/drivers/gpu/drm/i915/intel_guc_loader.c b/drivers/gpu/drm/i915/intel_guc_loader.c
index 759ab34..52d78ff 100644
--- a/drivers/gpu/drm/i915/intel_guc_loader.c
+++ b/drivers/gpu/drm/i915/intel_guc_loader.c
@@ -655,6 +655,21 @@ void intel_uc_fw_fetch(struct drm_i915_private *dev_priv,
 	uc_fw->fetch_status = INTEL_UC_FIRMWARE_FAIL;
 }
 
+void sanitize_slpc_option(struct drm_i915_private *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;
+}
+
 /**
  * intel_guc_init() - define parameters and fetch firmware
  * @dev_priv:	i915 device private
@@ -704,16 +719,19 @@ void intel_guc_init(struct drm_i915_private *dev_priv)
 
 	/* Early (and silent) return if GuC loading is disabled */
 	if (!i915.enable_guc_loading)
-		return;
+		goto out;
 	if (fw_path == NULL)
-		return;
+		goto out;
 	if (*fw_path == '\0')
-		return;
+		goto out;
 
 	guc_fw->fetch_status = INTEL_UC_FIRMWARE_PENDING;
 	DRM_DEBUG_DRIVER("GuC firmware pending, path %s\n", fw_path);
 	intel_uc_fw_fetch(dev_priv, guc_fw);
 	/* status must now be FAIL or SUCCESS */
+
+out:
+	sanitize_slpc_option(dev_priv);
 }
 
 /**
-- 
1.9.1