Map remapped mmio page to process space

HDP conherence registers are remapped at driver level
to an empty page in mmio space (the remapped mmio page).
This change allocate and map the remapped mmio page to
process space.



Change-Id: I89c405c41870a79c5b58eea0d8e564aa35f55182
Signed-off-by: Oak Zeng <Oak.Zeng@amd.com>

include/linux/kfd_ioctl.h

@@ -400,6 +400,7 @@ struct kfd_ioctl_acquire_vm_args {
 #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)
@@ -437,6 +438,14 @@ struct kfd_ioctl_free_memory_of_gpu_args {
 	__u64 handle;		/* to KFD */
 };
 
+/* Register offset inside the remapped mmio page
+ */
+enum kfd_mmio_remap {
+	KFD_MMIO_REMAP_HDP_MEM_FLUSH_CNTL = 0,
+	KFD_MMIO_REMAP_HDP_REG_FLUSH_CNTL = 4,
+};
+
+
 /* Map memory to one or more GPUs
  *
  * @handle:                memory handle returned by alloc