1 files changed, 237 insertions, 0 deletions
diff --git a/Documentation/gpu/rfc/i915_gem_lmem.h b/Documentation/gpu/rfc/i915_gem_lmem.h
new file mode 100644
index 000000000000..d9c61bea0556
--- /dev/null
+++ b/Documentation/gpu/rfc/i915_gem_lmem.h
@@ -0,0 +1,237 @@
+/**
+ * enum drm_i915_gem_memory_class - Supported memory classes
+ */
+enum drm_i915_gem_memory_class {
+	/** @I915_MEMORY_CLASS_SYSTEM: System memory */
+	I915_MEMORY_CLASS_SYSTEM = 0,
+	/** @I915_MEMORY_CLASS_DEVICE: Device local-memory */
+	I915_MEMORY_CLASS_DEVICE,
+};
+
+/**
+ * struct drm_i915_gem_memory_class_instance - Identify particular memory region
+ */
+struct drm_i915_gem_memory_class_instance {
+	/** @memory_class: See enum drm_i915_gem_memory_class */
+	__u16 memory_class;
+
+	/** @memory_instance: Which instance */
+	__u16 memory_instance;
+};
+
+/**
+ * struct drm_i915_memory_region_info - Describes one region as known to the
+ * driver.
+ *
+ * Note that we reserve some stuff here for potential future work. As an example
+ * we might want expose the capabilities for a given region, which could include
+ * things like if the region is CPU mappable/accessible, what are the supported
+ * mapping types etc.
+ *
+ * Note that to extend struct drm_i915_memory_region_info and struct
+ * drm_i915_query_memory_regions in the future the plan is to do the following:
+ *
+ * .. code-block:: C
+ *
+ *	struct drm_i915_memory_region_info {
+ *		struct drm_i915_gem_memory_class_instance region;
+ *		union {
+ *			__u32 rsvd0;
+ *			__u32 new_thing1;
+ *		};
+ *		...
+ *		union {
+ *			__u64 rsvd1[8];
+ *			struct {
+ *				__u64 new_thing2;
+ *				__u64 new_thing3;
+ *				...
+ *			};
+ *		};
+ *	};
+ *
+ * With this things should remain source compatible between versions for
+ * userspace, even as we add new fields.
+ *
+ * Note this is using both struct drm_i915_query_item and struct drm_i915_query.
+ * For this new query we are adding the new query id DRM_I915_QUERY_MEMORY_REGIONS
+ * at &drm_i915_query_item.query_id.
+ */
+struct drm_i915_memory_region_info {
+	/** @region: The class:instance pair encoding */
+	struct drm_i915_gem_memory_class_instance region;
+
+	/** @rsvd0: MBZ */
+	__u32 rsvd0;
+
+	/** @probed_size: Memory probed by the driver (-1 = unknown) */
+	__u64 probed_size;
+
+	/** @unallocated_size: Estimate of memory remaining (-1 = unknown) */
+	__u64 unallocated_size;
+
+	/** @rsvd1: MBZ */
+	__u64 rsvd1[8];
+};
+
+/**
+ * struct drm_i915_query_memory_regions
+ *
+ * The region info query enumerates all regions known to the driver by filling
+ * in an array of struct drm_i915_memory_region_info structures.
+ *
+ * Example for getting the list of supported regions:
+ *
+ * .. code-block:: C
+ *
+ *	struct drm_i915_query_memory_regions *info;
+ *	struct drm_i915_query_item item = {
+ *		.query_id = DRM_I915_QUERY_MEMORY_REGIONS;
+ *	};
+ *	struct drm_i915_query query = {
+ *		.num_items = 1,
+ *		.items_ptr = (uintptr_t)&item,
+ *	};
+ *	int err, i;
+ *
+ *	// First query the size of the blob we need, this needs to be large
+ *	// enough to hold our array of regions. The kernel will fill out the
+ *	// item.length for us, which is the number of bytes we need.
+ *	err = ioctl(fd, DRM_IOCTL_I915_QUERY, &query);
+ *	if (err) ...
+ *
+ *	info = calloc(1, item.length);
+ *	// Now that we allocated the required number of bytes, we call the ioctl
+ *	// again, this time with the data_ptr pointing to our newly allocated
+ *	// blob, which the kernel can then populate with the all the region info.
+ *	item.data_ptr = (uintptr_t)&info,
+ *
+ *	err = ioctl(fd, DRM_IOCTL_I915_QUERY, &query);
+ *	if (err) ...
+ *
+ *	// We can now access each region in the array
+ *	for (i = 0; i < info->num_regions; i++) {
+ *		struct drm_i915_memory_region_info mr = info->regions[i];
+ *		u16 class = mr.region.class;
+ *		u16 instance = mr.region.instance;
+ *
+ *		....
+ *	}
+ *
+ *	free(info);
+ */
+struct drm_i915_query_memory_regions {
+	/** @num_regions: Number of supported regions */
+	__u32 num_regions;
+
+	/** @rsvd: MBZ */
+	__u32 rsvd[3];
+
+	/** @regions: Info about each supported region */
+	struct drm_i915_memory_region_info regions[];
+};
+
+#define DRM_I915_GEM_CREATE_EXT		0xdeadbeaf
+#define DRM_IOCTL_I915_GEM_CREATE_EXT	DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_GEM_CREATE_EXT, struct drm_i915_gem_create_ext)
+
+/**
+ * struct drm_i915_gem_create_ext - Existing gem_create behaviour, with added
+ * extension support using struct i915_user_extension.
+ *
+ * Note that in the future we want to have our buffer flags here, at least for
+ * the stuff that is immutable. Previously we would have two ioctls, one to
+ * create the object with gem_create, and another to apply various parameters,
+ * however this creates some ambiguity for the params which are considered
+ * immutable. Also in general we're phasing out the various SET/GET ioctls.
+ */
+struct drm_i915_gem_create_ext {
+	/**
+	 * @size: Requested size for the object.
+	 *
+	 * The (page-aligned) allocated size for the object will be returned.
+	 *
+	 * Note that for some devices we have might have further minimum
+	 * page-size restrictions(larger than 4K), like for device local-memory.
+	 * However in general the final size here should always reflect any
+	 * rounding up, if for example using the I915_GEM_CREATE_EXT_MEMORY_REGIONS
+	 * extension to place the object in device local-memory.
+	 */
+	__u64 size;
+	/**
+	 * @handle: Returned handle for the object.
+	 *
+	 * Object handles are nonzero.
+	 */
+	__u32 handle;
+	/** @flags: MBZ */
+	__u32 flags;
+	/**
+	 * @extensions: The chain of extensions to apply to this object.
+	 *
+	 * This will be useful in the future when we need to support several
+	 * different extensions, and we need to apply more than one when
+	 * creating the object. See struct i915_user_extension.
+	 *
+	 * If we don't supply any extensions then we get the same old gem_create
+	 * behaviour.
+	 *
+	 * For I915_GEM_CREATE_EXT_MEMORY_REGIONS usage see
+	 * struct drm_i915_gem_create_ext_memory_regions.
+	 */
+#define I915_GEM_CREATE_EXT_MEMORY_REGIONS 0
+	__u64 extensions;
+};
+
+/**
+ * struct drm_i915_gem_create_ext_memory_regions - The
+ * I915_GEM_CREATE_EXT_MEMORY_REGIONS extension.
+ *
+ * Set the object with the desired set of placements/regions in priority
+ * order. Each entry must be unique and supported by the device.
+ *
+ * This is provided as an array of struct drm_i915_gem_memory_class_instance, or
+ * an equivalent layout of class:instance pair encodings. See struct
+ * drm_i915_query_memory_regions and DRM_I915_QUERY_MEMORY_REGIONS for how to
+ * query the supported regions for a device.
+ *
+ * As an example, on discrete devices, if we wish to set the placement as
+ * device local-memory we can do something like:
+ *
+ * .. code-block:: C
+ *
+ *	struct drm_i915_gem_memory_class_instance region_lmem = {
+ *              .memory_class = I915_MEMORY_CLASS_DEVICE,
+ *              .memory_instance = 0,
+ *      };
+ *      struct drm_i915_gem_create_ext_memory_regions regions = {
+ *              .base = { .name = I915_GEM_CREATE_EXT_MEMORY_REGIONS },
+ *              .regions = (uintptr_t)&region_lmem,
+ *              .num_regions = 1,
+ *      };
+ *      struct drm_i915_gem_create_ext create_ext = {
+ *              .size = 16 * PAGE_SIZE,
+ *              .extensions = (uintptr_t)&regions,
+ *      };
+ *
+ *      int err = ioctl(fd, DRM_IOCTL_I915_GEM_CREATE_EXT, &create_ext);
+ *      if (err) ...
+ *
+ * At which point we get the object handle in &drm_i915_gem_create_ext.handle,
+ * along with the final object size in &drm_i915_gem_create_ext.size, which
+ * should account for any rounding up, if required.
+ */
+struct drm_i915_gem_create_ext_memory_regions {
+	/** @base: Extension link. See struct i915_user_extension. */
+	struct i915_user_extension base;
+
+	/** @pad: MBZ */
+	__u32 pad;
+	/** @num_regions: Number of elements in the @regions array. */
+	__u32 num_regions;
+	/**
+	 * @regions: The regions/placements array.
+	 *
+	 * An array of struct drm_i915_gem_memory_class_instance.
+	 */
+	__u64 regions;
+};