[PATCH v3 2/9] image: android: Add routine to get dtbo params

[Sam Protsenko]

Android Boot Image v1 adds "Recovery DTB" field in image header and
associate payload in boot image itself [1]. Payload should be in
Android DTB/DTBO format [2]. That "Recovery DTB" area should be only
populated for non-A/B devices, and only in recovery image.

Add function to get an address and size of that payload. That function
can be further used e.g. in 'abootimg' command to provide the user a way
to get the address of recovery dtbo from U-Boot shell, which can be
further parsed using 'adtimg' command.

[1] https://source.android.com/devices/bootloader/boot-image-header
[2] https://source.android.com/devices/architecture/dto/partitions

Signed-off-by: Sam Protsenko <semen.protsenko at linaro.org>
---
 common/image-android.c | 61 ++++++++++++++++++++++++++++++++++++++++++
 include/image.h        |  1 +
 2 files changed, 62 insertions(+)

diff --git a/common/image-android.c b/common/image-android.c
index 1ccad6c556..5d6669ceab 100644
--- a/common/image-android.c
+++ b/common/image-android.c
@@ -197,6 +197,67 @@ int android_image_get_second(const struct andr_img_hdr *hdr,
 	return 0;
 }
 
+/**
+ * android_image_get_dtbo() - Get address and size of recovery DTBO image.
+ * @hdr_addr: Boot image header address
+ * @addr: If not NULL, will contain address of recovery DTBO image
+ * @size: If not NULL, will contain size of recovery DTBO image
+ *
+ * Get the address and size of DTBO image in "Recovery DTBO" area of Android
+ * Boot Image in RAM. The format of this image is Android DTBO (see
+ * corresponding "DTB/DTBO Partitions" AOSP documentation for details). Once
+ * the address is obtained from this function, one can use 'adtimg' U-Boot
+ * command or android_dt_*() functions to extract desired DTBO blob.
+ *
+ * This DTBO (included in boot image) is only needed for non-A/B devices, and it
+ * only can be found in recovery image. On A/B devices we can always rely on
+ * "dtbo" partition. See "Including DTBO in Recovery for Non-A/B Devices" in
+ * AOSP documentation for details.
+ *
+ * Return: true on success or false on error.
+ */
+bool android_image_get_dtbo(ulong hdr_addr, ulong *addr, u32 *size)
+{
+	const struct andr_img_hdr *hdr;
+	ulong dtbo_img_addr;
+	bool res = true;
+
+	hdr = map_sysmem(hdr_addr, sizeof(*hdr));
+	if (android_image_check_header(hdr)) {
+		printf("Error: Boot Image header is incorrect\n");
+		res = false;
+		goto exit;
+	}
+
+	if (hdr->header_version < 1) {
+		printf("Error: header_version must be >= 1 to get dtbo\n");
+		res = false;
+		goto exit;
+	}
+
+	if (hdr->recovery_dtbo_size == 0) {
+		printf("Error: recovery_dtbo_size is 0\n");
+		res = false;
+		goto exit;
+	}
+
+	/* Calculate the address of DTB area in boot image */
+	dtbo_img_addr = hdr_addr;
+	dtbo_img_addr += hdr->page_size;
+	dtbo_img_addr += ALIGN(hdr->kernel_size, hdr->page_size);
+	dtbo_img_addr += ALIGN(hdr->ramdisk_size, hdr->page_size);
+	dtbo_img_addr += ALIGN(hdr->second_size, hdr->page_size);
+
+	if (addr)
+		*addr = dtbo_img_addr;
+	if (size)
+		*size = hdr->recovery_dtbo_size;
+
+exit:
+	unmap_sysmem(hdr);
+	return res;
+}
+
 /**
  * android_image_get_dtb_img_addr() - Get the address of DTB area in boot image.
  * @hdr_addr: Boot image header address
diff --git a/include/image.h b/include/image.h
index 8e81166be4..b8d821605b 100644
--- a/include/image.h
+++ b/include/image.h
@@ -1333,6 +1333,7 @@ int android_image_get_ramdisk(const struct andr_img_hdr *hdr,
 			      ulong *rd_data, ulong *rd_len);
 int android_image_get_second(const struct andr_img_hdr *hdr,
 			      ulong *second_data, ulong *second_len);
+bool android_image_get_dtbo(ulong hdr_addr, ulong *addr, u32 *size);
 bool android_image_get_dtb_by_index(ulong hdr_addr, u32 index, ulong *addr,
 				    u32 *size);
 ulong android_image_get_end(const struct andr_img_hdr *hdr);
-- 
2.24.0