U-Boot: Add a command to read raw blocks from a partition.

- I don't know how this doesn't exist.  I'm going to use this to move
  the kernel + a U-Boot script to the kernel partition.

TEST=Used "read" command to successfully load a U-Boot script off of MMC
partition 2.
BUG=none

Review URL: http://codereview.chromium.org/3373004

Change-Id: If8a3497e6c284ff466434b80238fe9dfb6914aa8

1 files changed, 107 insertions, 0 deletions

diff --git a/common/cmd_read.c b/common/cmd_read.c
new file mode 100644
index 00000000000..d175dbf12f8
--- /dev/null
+++ b/common/cmd_read.c
@@ -0,0 +1,107 @@
+/*
+ * Copyright 2010, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ * * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Alternatively, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") version 2 as published by the Free
+ * Software Foundation.
+ */
+
+#include <common.h>
+#include <command.h>
+#include <part.h>
+
+int do_read (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+{
+	char *ep;
+	block_dev_desc_t *dev_desc = NULL;
+	int dev;
+	int part = 0;
+	disk_partition_t part_info;
+	ulong offset = 0u;
+	ulong limit = 0u;
+	void *addr;
+	uint blk;
+	uint cnt;
+
+	if (argc != 6) {
+		cmd_usage (cmdtp);
+		return 1;
+	}
+
+	dev = (int)simple_strtoul (argv[2], &ep, 16);
+	if (*ep) {
+		if (*ep != ':') {
+			printf ("Invalid block device %s\n", argv[2]);
+			return 1;
+		}
+		part = (int)simple_strtoul (++ep, NULL, 16);
+	}
+
+	dev_desc = get_dev (argv[1], dev);
+	if (dev_desc == NULL) {
+		printf ("Block device %s %d not supported\n", argv[1], dev);
+		return 1;
+	}
+
+	addr = (void *)simple_strtoul (argv[3], NULL, 16);
+	blk = simple_strtoul (argv[4], NULL, 16);
+	cnt = simple_strtoul (argv[5], NULL, 16);
+
+	if (part != 0) {
+		if (get_partition_info (dev_desc, part, &part_info)) {
+			printf ("Cannot find partition %d\n", part);
+			return 1;
+		}
+		offset = part_info.start;
+		limit = part_info.size;
+	} else {
+		/* Largest address not available in block_dev_desc_t. */
+		limit = ~0;
+	}
+
+	if (cnt + blk > limit) {
+		printf ("Read out of range\n");
+		return 1;
+	}
+
+	if (dev_desc->block_read (dev, offset + blk, cnt, addr) < 0) {
+		printf ("Error reading blocks\n");
+		return 1;
+	}
+
+	return 0;
+}
+
+U_BOOT_CMD(
+	read,	6,	0,	do_read,
+	"Load binary data from a partition",
+	"<interface> <dev[:part]> addr blk# cnt"
+);
+