remoteproc: do cache invalidation before reading rsc_table status

Do a cache invalidation before reading the resource table's status
since this ca be in a cacheable region.

Make this optional, based on VIRTIO_CACHED_RSC_TABLE.

Signed-off-by: Iuliana Prodan <iuliana.prodan@nxp.com>

cmake/options.cmake

@@ -90,6 +90,12 @@ if (WITH_DCACHE_BUFFERS)
   add_definitions(-DVIRTIO_CACHED_BUFFERS)
 endif (WITH_DCACHE_BUFFERS)
 
+option (WITH_DCACHE_RSC_TABLE "Build with resource table cache operations enabled" OFF)
+
+if (WITH_DCACHE_RSC_TABLE)
+  add_definitions(-DVIRTIO_CACHED_RSC_TABLE)
+endif (WITH_DCACHE_RSC_TABLE)
+
 # Set the complication flags
 set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wextra")
 

lib/include/openamp/remoteproc_virtio.h

@@ -15,6 +15,7 @@
 #include <metal/io.h>
 #include <metal/list.h>
 #include <openamp/virtio.h>
+#include <metal/cache.h>
 
 #if defined __cplusplus
 extern "C" {
@@ -23,6 +24,15 @@ extern "C" {
 /* maximum number of vring descriptors for a vdev limited by 16-bit data type */
 #define	RPROC_MAX_VRING_DESC	USHRT_MAX
 
+/* cache invalidation helpers for resource table */
+#ifdef VIRTIO_CACHED_RSC_TABLE
+#define RSC_TABLE_FLUSH(x)		metal_cache_flush(&x, sizeof(x))
+#define RSC_TABLE_INVALIDATE(x)		metal_cache_invalidate(&x, sizeof(x))
+#else
+#define RSC_TABLE_FLUSH(x)		do { } while (0)
+#define RSC_TABLE_INVALIDATE(x)		do { } while (0)
+#endif /* VIRTIO_CACHED_RSC_TABLE */
+
 /* define vdev notification function user should implement */
 typedef int (*rpvdev_notify_func)(void *priv, uint32_t id);
 

lib/remoteproc/remoteproc_virtio.c

@@ -40,6 +40,9 @@ static unsigned char rproc_virtio_get_status(struct virtio_device *vdev)
 	rpvdev = metal_container_of(vdev, struct remoteproc_virtio, vdev);
 	vdev_rsc = rpvdev->vdev_rsc;
 	io = rpvdev->vdev_rsc_io;
+
+	RSC_TABLE_INVALIDATE(vdev_rsc);
+
 	status = metal_io_read8(io,
 				metal_io_virt_to_offset(io, &vdev_rsc->status));
 	return status;