bootstd: cros: Move partition reading into a function

Move the code which reads a partition into its own function. Add a
constant for the number of bytes to 'probe' at the start of the partition.

Signed-off-by: Simon Glass <sjg@chromium.org>

diff --git a/boot/bootmeth_cros.c b/boot/bootmeth_cros.c
index 6179a547f74a8c9dc5fcaaa6542384285efae34c..f6fb521f206585599970d1d33ca20006cb69b098 100644 (file)
--- a/boot/bootmeth_cros.c
+++ b/boot/bootmeth_cros.c
@@ -23,6 +23,8 @@
 #include <linux/sizes.h>
 
 enum {
+       PROBE_SIZE      = SZ_4K,        /* initial bytes read from partition */
+
        /* Offsets in the kernel-partition header */
        KERN_START      = 0x4f0,
        KERN_SIZE       = 0x518,
@@ -77,6 +79,51 @@ static int copy_cmdline(const char *from, const char *uuid, char **bufp)
        return 0;
 }
 
+/**
+ * scan_part() - Scan a kernel partition to see if has a ChromeOS header
+ *
+ * This reads the first PROBE_SIZE of a partition, loookng for CHROMEOS
+ *
+ * @blk: Block device to scan
+ * @partnum: Partition number to scan
+ * @info: Please to put partition info
+ * @hdrp: Return allocated keyblock header on success
+ */
+static int scan_part(struct udevice *blk, int partnum,
+                    struct disk_partition *info, void **hdrp)
+{
+       struct blk_desc *desc = dev_get_uclass_plat(blk);
+       struct vb2_keyblock *hdr;
+       ulong num_blks;
+       int ret;
+
+       ret = part_get_info(desc, partnum, info);
+       if (ret)
+               return log_msg_ret("part", ret);
+
+       /* Make a buffer for the header information */
+       num_blks = PROBE_SIZE >> desc->log2blksz;
+       log_debug("Reading header, blk=%s, start=%lx, blocks=%lx\n",
+                 blk->name, (ulong)info->start, num_blks);
+       hdr = memalign(SZ_1K, PROBE_SIZE);
+       if (!hdr)
+               return log_msg_ret("hdr", -ENOMEM);
+       ret = blk_read(blk, info->start, num_blks, hdr);
+       if (ret != num_blks) {
+               free(hdr);
+               return log_msg_ret("inf", -EIO);
+       }
+
+       if (memcmp("CHROMEOS", hdr, 8)) {
+               free(hdr);
+               return -ENOENT;
+       }
+
+       *hdrp = hdr;
+
+       return 0;
+}
+
 static int cros_read_bootflow(struct udevice *dev, struct bootflow *bflow)
 {
        struct blk_desc *desc = dev_get_uclass_plat(bflow->blk);
@@ -93,23 +140,10 @@ static int cros_read_bootflow(struct udevice *dev, struct bootflow *bflow)
                return log_msg_ret("max", -ENOENT);
 
        /* Check partition 2 */
-       ret = part_get_info(desc, 2, &info);
+       ret = scan_part(bflow->blk, 2, &info, &hdr);
        if (ret)
-               return log_msg_ret("part", ret);
-
-       /* Make a buffer for the header information */
-       num_blks = SZ_4K >> desc->log2blksz;
-       log_debug("Reading header, blk=%s, start=%lx, blocks=%lx\n",
-                 bflow->blk->name, (ulong)info.start, num_blks);
-       hdr = memalign(SZ_1K, SZ_4K);
-       if (!hdr)
-               return log_msg_ret("hdr", -ENOMEM);
-       ret = blk_read(bflow->blk, info.start, num_blks, hdr);
-       if (ret != num_blks)
-               return log_msg_ret("inf", -EIO);
-
-       if (memcmp("CHROMEOS", hdr, 8))
-               return -ENOENT;
+               return log_msg_ret("scan", ret);
+       bflow->part = 2;
 
        log_info("Header at %lx\n", (ulong)map_to_sysmem(hdr));
        start = *(u32 *)(hdr + KERN_START);