virtio: cmd: Add virtio command for virtio devices

Add 'virtio' command in U-Boot command line.

Signed-off-by: Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

cmd/virtio.c

@@ -0,0 +1,38 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2018, Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
+ * Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
+ */
+
+#include <common.h>
+#include <command.h>
+#include <dm.h>
+#include <virtio_types.h>
+#include <virtio.h>
+
+static int virtio_curr_dev;
+
+static int do_virtio(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+{
+	if (argc == 2 && !strcmp(argv[1], "scan")) {
+		/* make sure all virtio devices are enumerated */
+		virtio_init();
+
+		return CMD_RET_SUCCESS;
+	}
+
+	return blk_common_cmd(argc, argv, IF_TYPE_VIRTIO, &virtio_curr_dev);
+}
+
+U_BOOT_CMD(
+	virtio, 8, 1, do_virtio,
+	"virtio block devices sub-system",
+	"scan - initialize virtio bus\n"
+	"virtio info - show all available virtio block devices\n"
+	"virtio device [dev] - show or set current virtio block device\n"
+	"virtio part [dev] - print partition table of one or all virtio block devices\n"
+	"virtio read addr blk# cnt - read `cnt' blocks starting at block\n"
+	"     `blk#' to memory address `addr'\n"
+	"virtio write addr blk# cnt - write `cnt' blocks starting at block\n"
+	"     `blk#' from memory address `addr'"
+);