Extend the query ioctl to allow querying the count of the available L3
Banks on a given engine.

Testcase: igt@i915_query@query-l3-bank-count
Test-with: 20230921220001.3793008-1-jonathan.cav...@intel.com
Signed-off-by: Jonathan Cavitt <jonathan.cav...@intel.com>
---
uAPI change requested by Compute UMD.
Changes to Compute UMD will be posted shortly.

v2:
- Remove extra period.
- Return -EINVAL instead of -ENODEV.
- Add testcase and UMD explanation to comments.

 drivers/gpu/drm/i915/gt/intel_gt.c      | 26 +++++++++++++++++++
 drivers/gpu/drm/i915/gt/intel_gt.h      |  3 +++
 drivers/gpu/drm/i915/gt/intel_gt_regs.h |  1 +
 drivers/gpu/drm/i915/i915_query.c       | 34 +++++++++++++++++++++++++
 include/uapi/drm/i915_drm.h             | 13 ++++++++++
 5 files changed, 77 insertions(+)

diff --git a/drivers/gpu/drm/i915/gt/intel_gt.c 
b/drivers/gpu/drm/i915/gt/intel_gt.c
index 449f0b7fc8434..3f29eb3510bac 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt.c
@@ -884,6 +884,32 @@ static int intel_gt_tile_setup(struct intel_gt *gt, 
phys_addr_t phys_addr)
        return 0;
 }
 
+int intel_count_l3_banks(struct drm_i915_private *i915,
+                        struct intel_engine_cs *engine)
+{
+       struct intel_gt *gt = engine->gt;
+       struct intel_uncore *uncore = gt->uncore;
+       intel_wakeref_t wakeref;
+       u32 count, store;
+
+       /* L3 Banks Counting not supported prior to version 12 */
+       if (GRAPHICS_VER(i915) < 12)
+               return -EINVAL;
+
+       if (IS_PONTEVECCHIO(i915)) {
+               with_intel_runtime_pm(uncore->rpm, wakeref)
+                       store = intel_uncore_read(uncore, GEN10_MIRROR_FUSE3);
+               count = hweight32(REG_FIELD_GET(GEN12_MEML3_EN_MASK, store)) * 
4 *
+                       hweight32(REG_FIELD_GET(XEHPC_GT_L3_MODE_MASK, store));
+       } else if (GRAPHICS_VER_FULL(i915) > IP_VER(12, 50)) {
+               count = hweight32(gt->info.mslice_mask) * 8;
+       } else {
+               count = hweight32(gt->info.l3bank_mask);
+       }
+
+       return count;
+}
+
 int intel_gt_probe_all(struct drm_i915_private *i915)
 {
        struct pci_dev *pdev = to_pci_dev(i915->drm.dev);
diff --git a/drivers/gpu/drm/i915/gt/intel_gt.h 
b/drivers/gpu/drm/i915/gt/intel_gt.h
index 239848bcb2a42..4a05443418efd 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt.h
+++ b/drivers/gpu/drm/i915/gt/intel_gt.h
@@ -161,6 +161,9 @@ static inline bool intel_gt_is_wedged(const struct intel_gt 
*gt)
        return unlikely(test_bit(I915_WEDGED, &gt->reset.flags));
 }
 
+int intel_count_l3_banks(struct drm_i915_private *i915,
+                        struct intel_engine_cs *engine);
+
 int intel_gt_probe_all(struct drm_i915_private *i915);
 int intel_gt_tiles_init(struct drm_i915_private *i915);
 void intel_gt_release_all(struct drm_i915_private *i915);
diff --git a/drivers/gpu/drm/i915/gt/intel_gt_regs.h 
b/drivers/gpu/drm/i915/gt/intel_gt_regs.h
index 9f2a7d103ea5d..80925d0237cf4 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_regs.h
+++ b/drivers/gpu/drm/i915/gt/intel_gt_regs.h
@@ -571,6 +571,7 @@
 #define        GEN10_MIRROR_FUSE3                      _MMIO(0x9118)
 #define   GEN10_L3BANK_PAIR_COUNT              4
 #define   GEN10_L3BANK_MASK                    0x0F
+#define   XEHPC_GT_L3_MODE_MASK                        REG_GENMASK(7, 4)
 /* on Xe_HP the same fuses indicates mslices instead of L3 banks */
 #define   GEN12_MAX_MSLICES                    4
 #define   GEN12_MEML3_EN_MASK                  0x0F
diff --git a/drivers/gpu/drm/i915/i915_query.c 
b/drivers/gpu/drm/i915/i915_query.c
index 00871ef997920..bd3e68cf1bd10 100644
--- a/drivers/gpu/drm/i915/i915_query.c
+++ b/drivers/gpu/drm/i915/i915_query.c
@@ -10,6 +10,7 @@
 #include "i915_perf.h"
 #include "i915_query.h"
 #include "gt/intel_engine_user.h"
+#include "gt/intel_gt.h"
 #include <uapi/drm/i915_drm.h>
 
 static int copy_query_item(void *query_hdr, size_t query_sz,
@@ -551,6 +552,38 @@ static int query_hwconfig_blob(struct drm_i915_private 
*i915,
        return hwconfig->size;
 }
 
+static int
+query_l3bank_count(struct drm_i915_private *i915,
+                  struct drm_i915_query_item *query_item)
+{
+       struct drm_i915_query_memory_regions __user *query_ptr =
+               u64_to_user_ptr(query_item->data_ptr);
+       struct i915_engine_class_instance classinstance;
+       struct intel_engine_cs *engine;
+       int count;
+
+       if (query_item->length == 0)
+               return sizeof(count);
+
+       classinstance = *((struct i915_engine_class_instance 
*)&query_item->flags);
+
+       engine = intel_engine_lookup_user(i915, (u8)classinstance.engine_class,
+                                         (u8)classinstance.engine_instance);
+
+       if (!engine)
+               return -EINVAL;
+
+       count = intel_count_l3_banks(i915, engine);
+
+       if (count < 0)
+               return count;
+
+       if (copy_to_user(query_ptr, &count, sizeof(count)))
+               return -EFAULT;
+
+       return sizeof(count);
+}
+
 static int (* const i915_query_funcs[])(struct drm_i915_private *dev_priv,
                                        struct drm_i915_query_item *query_item) 
= {
        query_topology_info,
@@ -559,6 +592,7 @@ static int (* const i915_query_funcs[])(struct 
drm_i915_private *dev_priv,
        query_memregion_info,
        query_hwconfig_blob,
        query_geometry_subslices,
+       query_l3bank_count,
 };
 
 int i915_query_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index 7000e5910a1d7..d651e8afe8f1a 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -3013,6 +3013,7 @@ struct drm_i915_query_item {
         *  - %DRM_I915_QUERY_MEMORY_REGIONS (see struct 
drm_i915_query_memory_regions)
         *  - %DRM_I915_QUERY_HWCONFIG_BLOB (see `GuC HWCONFIG blob uAPI`)
         *  - %DRM_I915_QUERY_GEOMETRY_SUBSLICES (see struct 
drm_i915_query_topology_info)
+        *  - %DRM_I915_QUERY_L3BANK_COUNT (see `L3 Bank Count Query uAPI`)
         */
        __u64 query_id;
 #define DRM_I915_QUERY_TOPOLOGY_INFO           1
@@ -3021,6 +3022,7 @@ struct drm_i915_query_item {
 #define DRM_I915_QUERY_MEMORY_REGIONS          4
 #define DRM_I915_QUERY_HWCONFIG_BLOB           5
 #define DRM_I915_QUERY_GEOMETRY_SUBSLICES      6
+#define DRM_I915_QUERY_L3BANK_COUNT            7
 /* Must be kept compact -- no holes and well documented */
 
        /**
@@ -3690,6 +3692,17 @@ struct drm_i915_gem_create_ext {
        __u64 extensions;
 };
 
+/**
+ * DOC: L3 Bank Count Query uAPI
+ *
+ * The L3 bank count query called through the query id
+ * DRM_I915_QUERY_L3BANK_COUNT and returns the count of
+ * the available L3 Banks on a given engine.
+ *
+ * The count itself is an integer, and since no additional
+ * data is returned, the count is returned as such.
+ */
+
 /**
  * struct drm_i915_gem_create_ext_memory_regions - The
  * I915_GEM_CREATE_EXT_MEMORY_REGIONS extension.
-- 
2.25.1

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