drm/amdkfd: Expose HDP registers to user space

Introduce a new memory type (KFD_IOC_ALLOC_MEM_FLAGS_MMIO_REMAP) and
expose mmio page of HDP registers to user space through this new
memory type.

v2: moved remapped hdp regs to adev struct
v3: rename the new memory type to ALLOC_MEM_FLAGS_MMIO_REMAP
v4: use more generic function name
v5: Fail remapped mmio allocation for asics before gfx9

Signed-off-by: Oak Zeng <[e-mail]>
Reviewed-by: Felix Kuehling <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c

···
 	return adev->gmc.xgmi.hive_id;
 }
 
+uint64_t amdgpu_amdkfd_get_mmio_remap_phys_addr(struct kgd_dev *kgd)
+{
+	struct amdgpu_device *adev = (struct amdgpu_device *)kgd;
+
+	return adev->rmmio_remap.bus_addr;
+}
+
 int amdgpu_amdkfd_submit_ib(struct kgd_dev *kgd, enum kgd_engine_type engine,
 				uint32_t vmid, uint64_t gpu_addr,
 				uint32_t *ib_cmd, uint32_t ib_len)

drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h

···
 				  uint32_t *flags);
 uint64_t amdgpu_amdkfd_get_vram_usage(struct kgd_dev *kgd);
 uint64_t amdgpu_amdkfd_get_hive_id(struct kgd_dev *kgd);
+uint64_t amdgpu_amdkfd_get_mmio_remap_phys_addr(struct kgd_dev *kgd);
 
 #define read_user_wptr(mmptr, wptr, dst)				\
 	({								\

drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c

···
 		if (!offset || !*offset)
 			return -EINVAL;
 		user_addr = *offset;
-	} else if (flags & ALLOC_MEM_FLAGS_DOORBELL) {
+	} else if (flags & (ALLOC_MEM_FLAGS_DOORBELL |
+			ALLOC_MEM_FLAGS_MMIO_REMAP)) {
 		domain = AMDGPU_GEM_DOMAIN_GTT;
 		alloc_domain = AMDGPU_GEM_DOMAIN_CPU;
 		bo_type = ttm_bo_type_sg;
···
 	/* Free the sync object */
 	amdgpu_sync_free(&mem->sync);
 
-	/* If the SG is not NULL, it's one we created for a doorbell
-	 * BO. We need to free it.
+	/* If the SG is not NULL, it's one we created for a doorbell or mmio
+	 * remap BO. We need to free it.
 	 */
 	if (mem->bo->tbo.sg) {
 		sg_free_table(mem->bo->tbo.sg);

drivers/gpu/drm/amd/amdkfd/kfd_chardev.c

···
 		if (args->size != kfd_doorbell_process_slice(dev))
 			return -EINVAL;
 		offset = kfd_get_process_doorbells(dev, p);
+	} else if (flags & KFD_IOC_ALLOC_MEM_FLAGS_MMIO_REMAP) {
+		if (args->size != PAGE_SIZE)
+			return -EINVAL;
+		offset = amdgpu_amdkfd_get_mmio_remap_phys_addr(dev->kgd);
+		if (!offset)
+			return -ENOMEM;
 	}
 
 	mutex_lock(&p->mutex);

drivers/gpu/drm/amd/include/kgd_kfd_interface.h

···
 #define ALLOC_MEM_FLAGS_GTT		(1 << 1)
 #define ALLOC_MEM_FLAGS_USERPTR		(1 << 2)
 #define ALLOC_MEM_FLAGS_DOORBELL	(1 << 3)
+#define ALLOC_MEM_FLAGS_MMIO_REMAP	(1 << 4)
 
 /*
  * Allocation flags attributes/access options.

include/uapi/linux/kfd_ioctl.h

···
 #define KFD_IOC_ALLOC_MEM_FLAGS_GTT		(1 << 1)
 #define KFD_IOC_ALLOC_MEM_FLAGS_USERPTR		(1 << 2)
 #define KFD_IOC_ALLOC_MEM_FLAGS_DOORBELL	(1 << 3)
+#define KFD_IOC_ALLOC_MEM_FLAGS_MMIO_REMAP	(1 << 4)
 /* Allocation flags: attributes/access options */
 #define KFD_IOC_ALLOC_MEM_FLAGS_WRITABLE	(1 << 31)
 #define KFD_IOC_ALLOC_MEM_FLAGS_EXECUTABLE	(1 << 30)