[PATCH 2/2] drm/i915/gt: Set default CCS mode '1'

Andi Shyti
2024-02-20T14:21:16Z

Since CCS automatic load balancing is disabled, we will impose a
fixed balancing policy that involves setting all the CCS engines
to work together on the same load.

Simultaneously, the user will see only 1 CCS rather than the
actual number. As of now, this change affects only DG2.

Fixes: d2eae8e98d59 ("drm/i915/dg2: Drop force_probe requirement")
Signed-off-by: Andi Shyti <andi.shyti@linux.intel.com>
Cc: Chris Wilson <chris.p.wilson@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Cc: <stable@vger.kernel.org> # v6.2+
---
drivers/gpu/drm/i915/gt/intel_gt.c | 11 +++++++++++
drivers/gpu/drm/i915/gt/intel_gt_regs.h | 2 ++
drivers/gpu/drm/i915/i915_drv.h | 17 +++++++++++++++++
drivers/gpu/drm/i915/i915_query.c | 5 +++--
4 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_gt.c b/drivers/gpu/drm/i915/gt/intel_gt.c
index a425db5ed3a2..e19df4ef47f6 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt.c
@@ -168,6 +168,14 @@ static void init_unused_rings(struct intel_gt *gt)
}
}

+static void intel_gt_apply_ccs_mode(struct intel_gt *gt)
+{
+ if (!IS_DG2(gt->i915))
+ return;
+
+ intel_uncore_write(gt->uncore, XEHP_CCS_MODE, 0);
+}
+
int intel_gt_init_hw(struct intel_gt *gt)
{
struct drm_i915_private *i915 = gt->i915;
@@ -195,6 +203,9 @@ int intel_gt_init_hw(struct intel_gt *gt)

intel_gt_init_swizzling(gt);

+ /* Configure CCS mode */
+ intel_gt_apply_ccs_mode(gt);
+
/*
* At least 830 can leave some of the unused rings
* "active" (ie. head != tail) after resume which
diff --git a/drivers/gpu/drm/i915/gt/intel_gt_regs.h b/drivers/gpu/drm/i915/gt/intel_gt_regs.h
index cf709f6c05ae..c148113770ea 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_regs.h
+++ b/drivers/gpu/drm/i915/gt/intel_gt_regs.h
@@ -1605,6 +1605,8 @@
#define GEN12_VOLTAGE_MASK REG_GENMASK(10, 0)
#define GEN12_CAGF_MASK REG_GENMASK(19, 11)

+#define XEHP_CCS_MODE _MMIO(0x14804)
+
#define GEN11_GT_INTR_DW(x) _MMIO(0x190018 + ((x) * 4))
#define GEN11_CSME (31)
#define GEN12_HECI_2 (30)
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index e81b3b2858ac..0853ffd3cb8d 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -396,6 +396,23 @@ static inline struct intel_gt *to_gt(const struct drm_i915_private *i915)
(engine__); \
(engine__) = rb_to_uabi_engine(rb_next(&(engine__)->uabi_node)))

+/*
+ * Exclude unavailable engines.
+ *
+ * Only the first CCS engine is utilized due to the disabling of CCS auto load
+ * balancing. As a result, all CCS engines operate collectively, functioning
+ * essentially as a single CCS engine, hence the count of active CCS engines is
+ * considered '1'.
+ * Currently, this applies to platforms with more than one CCS engine,
+ * specifically DG2.
+ */
+#define for_each_available_uabi_engine(engine__, i915__) \
+ for_each_uabi_engine(engine__, i915__) \
+ if ((IS_DG2(i915__)) && \
+ ((engine__)->uabi_class == I915_ENGINE_CLASS_COMPUTE) && \
+ ((engine__)->uabi_instance)) { } \
+ else
+
#define INTEL_INFO(i915) ((i915)->__info)
#define RUNTIME_INFO(i915) (&(i915)->__runtime)
#define DRIVER_CAPS(i915) (&(i915)->caps)
diff --git a/drivers/gpu/drm/i915/i915_query.c b/drivers/gpu/drm/i915/i915_query.c
index fa3e937ed3f5..2d41bda626a6 100644
--- a/drivers/gpu/drm/i915/i915_query.c
+++ b/drivers/gpu/drm/i915/i915_query.c
@@ -124,6 +124,7 @@ static int query_geometry_subslices(struct drm_i915_private *i915,
return fill_topology_info(sseu, query_item, sseu->geometry_subslice_mask);
}

+
static int
query_engine_info(struct drm_i915_private *i915,
struct drm_i915_query_item *query_item)
@@ -140,7 +141,7 @@ query_engine_info(struct drm_i915_private *i915,
if (query_item->flags)
return -EINVAL;

- for_each_uabi_engine(engine, i915)
+ for_each_available_uabi_engine(engine, i915)
num_uabi_engines++;

len = struct_size(query_ptr, engines, num_uabi_engines);
@@ -155,7 +156,7 @@ query_engine_info(struct drm_i915_private *i915,

info_ptr = &query_ptr->engines[0];

- for_each_uabi_engine(engine, i915) {
+ for_each_available_uabi_engine(engine, i915) {
info.engine.engine_class = engine->uabi_class;
info.engine.engine_instance = engine->uabi_instance;
info.flags = I915_ENGINE_INFO_HAS_LOGICAL_INSTANCE;
--
2.43.0