[PATCH 05/10] drm/amdgpu: add AMDGPU_INFO_SDMA_USERQ_DOORBELL ioctl

[Jesse Zhang <Jesse.Zhang@amd.com>]

From: "Jesse.zhang" <Jesse.zhang@amd.com>

New AMDGPU_INFO query that returns a per-fpriv GEM handle for the
kernel-owned BO backing the SDMA UMQ doorbell window, plus its size.
Userspace mmap()s that handle through the standard
AMDGPU_GEM_OP_MMAP / mmap() flow to obtain a CPU pointer to the
routable doorbell BAR window; each created SDMA usermode queue's
qword-slot offset inside that mapping is reported in
drm_amdgpu_userq_out.sdma_doorbell_offset_bytes.

Signed-off-by: Jesse Zhang <Jesse.Zhang@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c | 13 +++++++++++++
 include/uapi/drm/amdgpu_drm.h           | 16 ++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
index d88e4994c8c1..dbcfbe418e42 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
@@ -1425,6 +1425,19 @@ int amdgpu_info_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
 			return -EINVAL;
 		}
 	}
+	case AMDGPU_INFO_SDMA_USERQ_DOORBELL: {
+		struct drm_amdgpu_info_sdma_userq_doorbell db_info = {};
+		int r;
+
+		r = amdgpu_sdma_userq_doorbell_create_handle(adev, filp,
+							     &db_info.handle,
+							     &db_info.size_bytes);
+		if (r)
+			return r;
+		return copy_to_user(out, &db_info,
+				    min((size_t)size, sizeof(db_info)))
+			? -EFAULT : 0;
+	}
 	default:
 		DRM_DEBUG_KMS("Invalid request %d\n", info->query);
 		return -EINVAL;
diff --git a/include/uapi/drm/amdgpu_drm.h b/include/uapi/drm/amdgpu_drm.h
index 79e8bbda046b..533be8ad8a7e 100644
--- a/include/uapi/drm/amdgpu_drm.h
+++ b/include/uapi/drm/amdgpu_drm.h
@@ -1280,6 +1280,22 @@ struct drm_amdgpu_cs_chunk_cp_gfx_shadow {
 #define AMDGPU_INFO_GPUVM_FAULT			0x23
 /* query FW object size and alignment */
 #define AMDGPU_INFO_UQ_FW_AREAS			0x24
+/*
+ * SDMA usermode-queue doorbell window query.  Returns a per-fpriv GEM
+ * handle for a kernel-owned BO that backs the routable SDMA doorbell
+ * window, plus its byte size.  Userspace mmap()s the BO via the standard
+ * AMDGPU_GEM_OP_MMAP / mmap() flow to get a CPU pointer; each created
+ * SDMA usermode queue's slot offset inside that mapping is returned in
+ * drm_amdgpu_userq_out.sdma_doorbell_offset_bytes.
+ */
+#define AMDGPU_INFO_SDMA_USERQ_DOORBELL		0x25
+
+struct drm_amdgpu_info_sdma_userq_doorbell {
+	/* Per-fpriv GEM handle for the SDMA UMQ doorbell BO. */
+	__u32 handle;
+	/* Byte size of the BO (== mmappable window size). */
+	__u32 size_bytes;
+};
 
 #define AMDGPU_INFO_MMR_SE_INDEX_SHIFT	0
 #define AMDGPU_INFO_MMR_SE_INDEX_MASK	0xff
-- 
2.49.0