[Intel-gfx] [PATCH v2 2/2] drm/i915/icl: Add IOCTL for getting MOCS table version

[Tomasz Lis]

For Icelake and above, MOCS table for each platform is published
within bspec. The table is versioned, and new entries are assigned
a version number. Existing entries do not change and their version
is constant.

This introduces a parameter which allows getting max version number
of the MOCS entries currently supported, ie. value of 2 would mean
only version 1 and version 2 entries are initialized and can be used
by the user mode clients.

BSpec: 34007
Signed-off-by: Tomasz Lis <tomasz.lis at intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
Cc: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala at intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
Cc: Zhenyu Wang <zhenyuw at linux.intel.com>
Cc: Zhi A Wang <zhi.a.wang at intel.com>
Cc: Anuj Phogat <anuj.phogat at intel.com>
---
 drivers/gpu/drm/i915/i915_drv.c   |  6 ++++++
 drivers/gpu/drm/i915/intel_mocs.c | 12 ++++++++++++
 drivers/gpu/drm/i915/intel_mocs.h |  1 +
 include/uapi/drm/i915_drm.h       | 11 +++++++++++
 4 files changed, 30 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index baac35f..92fa8fd 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -53,6 +53,7 @@
 #include "i915_vgpu.h"
 #include "intel_drv.h"
 #include "intel_uc.h"
+#include "intel_mocs.h"
 
 static struct drm_driver driver;
 
@@ -444,6 +445,11 @@ static int i915_getparam_ioctl(struct drm_device *dev, void *data,
 	case I915_PARAM_MMAP_GTT_COHERENT:
 		value = INTEL_INFO(dev_priv)->has_coherent_ggtt;
 		break;
+	case I915_PARAM_MOCS_TABLE_VERSION:
+		value = intel_mocs_table_version(dev_priv);
+		if (!value)
+			return -ENODEV;
+		break;
 	default:
 		DRM_DEBUG("Unknown parameter %d\n", param->param);
 		return -EINVAL;
diff --git a/drivers/gpu/drm/i915/intel_mocs.c b/drivers/gpu/drm/i915/intel_mocs.c
index dc34e83..fc1e98b 100644
--- a/drivers/gpu/drm/i915/intel_mocs.c
+++ b/drivers/gpu/drm/i915/intel_mocs.c
@@ -469,6 +469,18 @@ static i915_reg_t mocs_register(enum intel_engine_id engine_id, int index)
 }
 
 /**
+ * intel_mocs_table_version() - get version of mocs table implementation
+ * @i915: i915 device struct.
+ */
+int intel_mocs_table_version(struct drm_i915_private *i915)
+{
+	if (IS_ICELAKE(i915))
+		return 1;
+	else
+		return 0;
+}
+
+/**
  * intel_mocs_init_engine() - emit the mocs control table
  * @engine:	The engine for whom to emit the registers.
  *
diff --git a/drivers/gpu/drm/i915/intel_mocs.h b/drivers/gpu/drm/i915/intel_mocs.h
index d89080d..dc1d64a 100644
--- a/drivers/gpu/drm/i915/intel_mocs.h
+++ b/drivers/gpu/drm/i915/intel_mocs.h
@@ -55,5 +55,6 @@
 int intel_rcs_context_init_mocs(struct i915_request *rq);
 void intel_mocs_init_l3cc_table(struct drm_i915_private *dev_priv);
 void intel_mocs_init_engine(struct intel_engine_cs *engine);
+int intel_mocs_table_version(struct drm_i915_private *i915);
 
 #endif
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index 298b2e1..16aafc4 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -559,6 +559,17 @@ typedef struct drm_i915_irq_wait {
  */
 #define I915_PARAM_MMAP_GTT_COHERENT	52
 
+/*
+ * Query MOCS table version used during hardware initialization.
+ *
+ * The MOCS table for each platform is published as part of bspec. Entries in
+ * the table are supposed to never be modified, but new enties are added, making
+ * more indexes in the table valid. This parameter informs which version
+ * of the table was used to initialize the currently used graphics hardware,
+ * and therefore which MOCS indexes are useable.
+ */
+#define I915_PARAM_MOCS_TABLE_VERSION	53
+
 typedef struct drm_i915_getparam {
 	__s32 param;
 	/*
-- 
2.7.4