[PATCH v2 11/15] drm/i915/gt: Store active CCS mask

Andi Shyti andi.shyti at linux.intel.com
Thu Aug 22 17:28:28 UTC 2024


To support upcoming patches, we need to store the current mask
for active CCS engines.

Active engines refer to those exposed to userspace via the UABI
engine list.

Signed-off-by: Andi Shyti <andi.shyti at linux.intel.com>
---
 drivers/gpu/drm/i915/gt/intel_gt_ccs_mode.c | 41 +++++++++++++++++++--
 drivers/gpu/drm/i915/gt/intel_gt_types.h    |  7 ++++
 2 files changed, 44 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_gt_ccs_mode.c b/drivers/gpu/drm/i915/gt/intel_gt_ccs_mode.c
index edb6a4b63826..5eead7b18f57 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_ccs_mode.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt_ccs_mode.c
@@ -12,6 +12,7 @@
 static void intel_gt_apply_ccs_mode(struct intel_gt *gt)
 {
 	unsigned long cslices_mask = CCS_MASK(gt);
+	unsigned long ccs_mask = gt->ccs.id_mask;
 	u32 mode_val = 0;
 	/* CCS engine id, i.e. the engines position in the engine's bitmask */
 	int engine;
@@ -55,7 +56,7 @@ static void intel_gt_apply_ccs_mode(struct intel_gt *gt)
 	 *   slice 2: ccs2
 	 *   slice 3: ccs3
 	 */
-	engine = __ffs(cslices_mask);
+	engine = __ffs(ccs_mask);
 
 	for (cslice = 0; cslice < I915_MAX_CCS; cslice++) {
 		if (!(cslices_mask & BIT(cslice))) {
@@ -86,7 +87,7 @@ static void intel_gt_apply_ccs_mode(struct intel_gt *gt)
 			 * CCS mode, will be used later to
 			 * reset to a flexible value
 			 */
-			engine = __ffs(cslices_mask);
+			engine = __ffs(ccs_mask);
 			continue;
 		}
 	}
@@ -94,13 +95,45 @@ static void intel_gt_apply_ccs_mode(struct intel_gt *gt)
 	gt->ccs.mode_reg_val = mode_val;
 }
 
+static void __update_ccs_mask(struct intel_gt *gt, u32 ccs_mode)
+{
+	unsigned long cslices_mask = CCS_MASK(gt);
+	int i;
+
+	/* Mask off all the CCS engines */
+	gt->ccs.id_mask = 0;
+
+	for_each_set_bit(i, &cslices_mask, I915_MAX_CCS) {
+		gt->ccs.id_mask |= BIT(i);
+
+		ccs_mode--;
+		if (!ccs_mode)
+			break;
+	}
+
+	/*
+	 * It's impossible for 'ccs_mode' to be zero at this point.
+	 * This scenario would only occur if the 'ccs_mode' provided by
+	 * the caller exceeded the total number of CCS engines, a condition
+	 * we check before calling the 'update_ccs_mask()' function.
+	 */
+	GEM_BUG_ON(ccs_mode);
+
+	/* Initialize the CCS mode setting */
+	intel_gt_apply_ccs_mode(gt);
+}
+
 void intel_gt_ccs_mode_init(struct intel_gt *gt)
 {
 	if (!IS_DG2(gt->i915))
 		return;
 
-	/* Initialize the CCS mode setting */
-	intel_gt_apply_ccs_mode(gt);
+	/*
+	 * Set CCS balance mode 1 in the ccs_mask.
+	 *
+	 * During init the workaround are not set up yet.
+	 */
+	__update_ccs_mask(gt, 1);
 }
 
 static ssize_t num_cslices_show(struct device *dev,
diff --git a/drivers/gpu/drm/i915/gt/intel_gt_types.h b/drivers/gpu/drm/i915/gt/intel_gt_types.h
index 71e43071da0b..641be69016e1 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_gt_types.h
@@ -219,6 +219,13 @@ struct intel_gt {
 	 */
 	struct {
 		u32 mode_reg_val;
+
+		/*
+		 * CCS id_mask is the command streamer instance
+		 * exposed to the user. While the CCS_MASK(gt)
+		 * is the available unfused compute slices.
+		 */
+		intel_engine_mask_t id_mask;
 	} ccs;
 
 	/*
-- 
2.45.2



More information about the dri-devel mailing list