[U-Boot] [PATCH 2/6] image: Implement a function to load Android Images.

[Alex Deymo <deymo@google.com>]

This patch implements the logic needed to load an Android boot image
from storage, since the size and kernel address in Android images is
defined in its header.

Signed-off-by: Alex Deymo <deymo@google.com>
---
 common/image-android.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++++++
 include/image.h        | 19 +++++++++++++++++++
 2 files changed, 70 insertions(+)

diff --git a/common/image-android.c b/common/image-android.c
index c668407817..f040f5b400 100644
--- a/common/image-android.c
+++ b/common/image-android.c
@@ -8,6 +8,7 @@
 #include <image.h>
 #include <android_image.h>
 #include <malloc.h>
+#include <mapmem.h>
 #include <errno.h>
 
 #define ANDROID_IMAGE_DEFAULT_KERNEL_ADDR	0x10008000
@@ -146,6 +147,56 @@ int android_image_get_ramdisk(const struct andr_img_hdr *hdr,
 	return 0;
 }
 
+long android_image_load(struct blk_desc *dev_desc,
+			const disk_partition_t *part_info,
+			unsigned long load_address,
+			unsigned long max_size) {
+	void *buf;
+	long blk_cnt, blk_read = 0;
+
+	if (max_size < part_info->blksz)
+		return -1;
+
+	/* We don't know the size of the Android image before reading the header
+	 * so we don't limit the size of the mapped memory.
+	 */
+	buf = map_sysmem(load_address, 0 /* size */);
+
+	/* Read the Android header first and then read the rest. */
+	if (blk_dread(dev_desc, part_info->start, 1, buf) != 1)
+		blk_read = -1;
+
+	if (!blk_read && android_image_check_header(buf) != 0) {
+		printf("** Invalid Android Image header **\n");
+		blk_read = -1;
+	}
+	if (!blk_read) {
+		blk_cnt = (android_image_get_end(buf) - (ulong)buf +
+			   part_info->blksz - 1) / part_info->blksz;
+		if (blk_cnt * part_info->blksz > max_size) {
+			debug("Android Image too big (%lu bytes, max %lu)\n",
+			      android_image_get_end(buf) - (ulong)buf,
+			      max_size);
+			blk_read = -1;
+		} else {
+			debug("Loading Android Image (%lu blocks) to 0x%lx... ",
+			      blk_cnt, load_address);
+			blk_read = blk_dread(dev_desc, part_info->start,
+					     blk_cnt, buf);
+		}
+	}
+
+	unmap_sysmem(buf);
+	if (blk_read < 0)
+		return blk_read;
+
+	debug("%lu blocks read: %s\n",
+	      blk_read, (blk_read == blk_cnt) ? "OK" : "ERROR");
+	if (blk_read != blk_cnt)
+		return -1;
+	return blk_read;
+}
+
 #if !defined(CONFIG_SPL_BUILD)
 /**
  * android_print_contents - prints out the contents of the Android format image
diff --git a/include/image.h b/include/image.h
index 2372518960..de448a9a01 100644
--- a/include/image.h
+++ b/include/image.h
@@ -1241,6 +1241,25 @@ ulong android_image_get_end(const struct andr_img_hdr *hdr);
 ulong android_image_get_kload(const struct andr_img_hdr *hdr);
 void android_print_contents(const struct andr_img_hdr *hdr);
 
+/** android_image_load - Load an Android Image from storage.
+ *
+ * Load an Android Image based on the header size in the storage. Return the
+ * number of bytes read from storage, which could be bigger than the actual
+ * Android Image as described in the header size. In case of error reading the
+ * image or if the image size needed to be read from disk is bigger than the
+ * the passed |max_size| a negative number is returned.
+ *
+ * @dev_desc:		The device where to read the image from
+ * @part_info:		The partition in |dev_desc| where to read the image from
+ * @load_address:	The address where the image will be loaded
+ * @max_size:		The maximum loaded size, in bytes
+ * @return the number of bytes read or a negative number in case of error.
+ */
+long android_image_load(struct blk_desc *dev_desc,
+			const disk_partition_t *part_info,
+			unsigned long load_address,
+			unsigned long max_size);
+
 #endif /* CONFIG_ANDROID_BOOT_IMAGE */
 
 /**
-- 
2.12.2.564.g063fe858b8-goog