parse the second area of android image

The second area of android image was intended to put a 2nd stage
bootloader but in practice were rarely used (in my knowledge).

An proposal was made to the AOSP to (re)use the second area as the dtb[1],
This patch itself doesn't depend on that proposal being accepted but it won't
be that helpful as well if that proposal won't be accepted. But don't do
any harm as well.

[1] https://android-review.googlesource.com/#/c/417447/
Signed-off-by: Bin Chen <bin.chen@linaro.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>

common/image-android.c

@@ -146,6 +146,25 @@ int android_image_get_ramdisk(const struct andr_img_hdr *hdr,
 	return 0;
 }
 
+int android_image_get_second(const struct andr_img_hdr *hdr,
+			      ulong *second_data, ulong *second_len)
+{
+	if (!hdr->second_size) {
+		*second_data = *second_len = 0;
+		return -1;
+	}
+
+	*second_data = (unsigned long)hdr;
+	*second_data += hdr->page_size;
+	*second_data += ALIGN(hdr->kernel_size, hdr->page_size);
+	*second_data += ALIGN(hdr->ramdisk_size, hdr->page_size);
+
+	printf("second address is 0x%lx\n",*second_data);
+
+	*second_len = hdr->second_size;
+	return 0;
+}
+
 #if !defined(CONFIG_SPL_BUILD)
 /**
  * android_print_contents - prints out the contents of the Android format image

include/image.h

@@ -1263,6 +1263,8 @@ int android_image_get_kernel(const struct andr_img_hdr *hdr, int verify,
 			     ulong *os_data, ulong *os_len);
 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);
 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);