+#ifdef CONFIG_ANDROID_BOOT_IMAGE
+/**
+ * Read Android boot image header from boot partition.
+ *
+ * @param[in] dev_desc MMC device descriptor
+ * @param[in] info Boot partition info
+ * @param[out] hdr Where to store read boot image header
+ *
+ * @return Boot image header sectors count or 0 on error
+ */
+static lbaint_t fb_mmc_get_boot_header(struct blk_desc *dev_desc,
+ disk_partition_t *info,
+ struct andr_img_hdr *hdr)
+{
+ ulong sector_size; /* boot partition sector size */
+ lbaint_t hdr_sectors; /* boot image header sectors count */
+ int res;
+
+ /* Calculate boot image sectors count */
+ sector_size = info->blksz;
+ hdr_sectors = DIV_ROUND_UP(sizeof(struct andr_img_hdr), sector_size);
+ if (hdr_sectors == 0) {
+ pr_err("invalid number of boot sectors: 0");
+ fastboot_fail("invalid number of boot sectors: 0");
+ return 0;
+ }
+
+ /* Read the boot image header */
+ res = blk_dread(dev_desc, info->start, hdr_sectors, (void *)hdr);
+ if (res != hdr_sectors) {
+ pr_err("cannot read header from boot partition");
+ fastboot_fail("cannot read header from boot partition");
+ return 0;
+ }
+
+ /* Check boot header magic string */
+ res = android_image_check_header(hdr);
+ if (res != 0) {
+ pr_err("bad boot image magic");
+ fastboot_fail("boot partition not initialized");
+ return 0;
+ }
+
+ return hdr_sectors;
+}
+
+/**
+ * Write downloaded zImage to boot partition and repack it properly.
+ *
+ * @param dev_desc MMC device descriptor
+ * @param download_buffer Address to fastboot buffer with zImage in it
+ * @param download_bytes Size of fastboot buffer, in bytes
+ *
+ * @return 0 on success or -1 on error
+ */
+static int fb_mmc_update_zimage(struct blk_desc *dev_desc,
+ void *download_buffer,
+ unsigned int download_bytes)
+{
+ uintptr_t hdr_addr; /* boot image header address */
+ struct andr_img_hdr *hdr; /* boot image header */
+ lbaint_t hdr_sectors; /* boot image header sectors */
+ u8 *ramdisk_buffer;
+ u32 ramdisk_sector_start;
+ u32 ramdisk_sectors;
+ u32 kernel_sector_start;
+ u32 kernel_sectors;
+ u32 sectors_per_page;
+ disk_partition_t info;
+ int res;
+
+ puts("Flashing zImage\n");
+
+ /* Get boot partition info */
+ res = part_get_info_by_name(dev_desc, BOOT_PARTITION_NAME, &info);
+ if (res < 0) {
+ pr_err("cannot find boot partition");
+ fastboot_fail("cannot find boot partition");
+ return -1;
+ }
+
+ /* Put boot image header in fastboot buffer after downloaded zImage */
+ hdr_addr = (uintptr_t)download_buffer + ALIGN(download_bytes, PAGE_SIZE);
+ hdr = (struct andr_img_hdr *)hdr_addr;
+
+ /* Read boot image header */
+ hdr_sectors = fb_mmc_get_boot_header(dev_desc, &info, hdr);
+ if (hdr_sectors == 0) {
+ pr_err("unable to read boot image header");
+ fastboot_fail("unable to read boot image header");
+ return -1;
+ }
+
+ /* Check if boot image has second stage in it (we don't support it) */
+ if (hdr->second_size > 0) {
+ pr_err("moving second stage is not supported yet");
+ fastboot_fail("moving second stage is not supported yet");
+ return -1;
+ }
+
+ /* Extract ramdisk location */
+ sectors_per_page = hdr->page_size / info.blksz;
+ ramdisk_sector_start = info.start + sectors_per_page;
+ ramdisk_sector_start += DIV_ROUND_UP(hdr->kernel_size, hdr->page_size) *
+ sectors_per_page;
+ ramdisk_sectors = DIV_ROUND_UP(hdr->ramdisk_size, hdr->page_size) *
+ sectors_per_page;
+
+ /* Read ramdisk and put it in fastboot buffer after boot image header */
+ ramdisk_buffer = (u8 *)hdr + (hdr_sectors * info.blksz);
+ res = blk_dread(dev_desc, ramdisk_sector_start, ramdisk_sectors,
+ ramdisk_buffer);
+ if (res != ramdisk_sectors) {
+ pr_err("cannot read ramdisk from boot partition");
+ fastboot_fail("cannot read ramdisk from boot partition");
+ return -1;
+ }
+
+ /* Write new kernel size to boot image header */
+ hdr->kernel_size = download_bytes;
+ res = blk_dwrite(dev_desc, info.start, hdr_sectors, (void *)hdr);
+ if (res == 0) {
+ pr_err("cannot writeback boot image header");
+ fastboot_fail("cannot write back boot image header");
+ return -1;
+ }
+
+ /* Write the new downloaded kernel */
+ kernel_sector_start = info.start + sectors_per_page;
+ kernel_sectors = DIV_ROUND_UP(hdr->kernel_size, hdr->page_size) *
+ sectors_per_page;
+ res = blk_dwrite(dev_desc, kernel_sector_start, kernel_sectors,
+ download_buffer);
+ if (res == 0) {
+ pr_err("cannot write new kernel");
+ fastboot_fail("cannot write new kernel");
+ return -1;
+ }
+
+ /* Write the saved ramdisk back */
+ ramdisk_sector_start = info.start + sectors_per_page;
+ ramdisk_sector_start += DIV_ROUND_UP(hdr->kernel_size, hdr->page_size) *
+ sectors_per_page;
+ res = blk_dwrite(dev_desc, ramdisk_sector_start, ramdisk_sectors,
+ ramdisk_buffer);
+ if (res == 0) {
+ pr_err("cannot write back original ramdisk");
+ fastboot_fail("cannot write back original ramdisk");
+ return -1;
+ }
+
+ puts("........ zImage was updated in boot partition\n");
+ fastboot_okay("");
+ return 0;
+}
+#endif
+