bootstd: cros: Simplify setup and cmdline expressions

Create a common base from which the other parts are offset and make all
of the offsets related to that. This makes the code a little easier to
read.

Use X86_ prefixes for the two values which are x86-specific.

Drop OFFSET_BASE since it is available in a header field.

Drop the unnecessary 'start' variable too.

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

diff --git a/boot/bootmeth_cros.c b/boot/bootmeth_cros.c
index 2a745621e30e86a97425a7462dc3ac99cbb371cd..05284713f67b4764592c90d7dabab1125a95b85c 100644 (file)
--- a/boot/bootmeth_cros.c
+++ b/boot/bootmeth_cros.c
@@ -27,9 +27,9 @@
 enum {
        PROBE_SIZE      = SZ_4K,        /* initial bytes read from partition */
 
-       SETUP_OFFSET    = 0x1000,       /* bytes before base */
-       CMDLINE_OFFSET  = 0x2000,       /* bytes before base */
-       OFFSET_BASE     = 0x100000,     /* assumed kernel load-address */
+       X86_SETUP_OFFSET = -0x1000,     /* setup offset relative to base */
+       CMDLINE_OFFSET  = -0x2000,      /* cmdline offset relative to base */
+       X86_KERNEL_OFFSET = 0x4000,     /* kernel offset relative to base */
 };
 
 static int cros_check(struct udevice *dev, struct bootflow_iter *iter)
@@ -126,7 +126,7 @@ static int scan_part(struct udevice *blk, int partnum,
 static int cros_read_bootflow(struct udevice *dev, struct bootflow *bflow)
 {
        struct blk_desc *desc = dev_get_uclass_plat(bflow->blk);
-       ulong base, start, setup, cmdline, num_blks, kern_base;
+       ulong base, setup, cmdline, num_blks, kern_base;
        const struct vb2_kernel_preamble *preamble;
        ulong body_offset, body_size;
        struct disk_partition info;
@@ -160,7 +160,6 @@ static int cros_read_bootflow(struct udevice *dev, struct bootflow *bflow)
                  preamble->header_version_major,
                  preamble->header_version_minor);
 
-       start = (ulong)preamble->bootloader_address;
        log_debug("  - load_address %lx, bl_addr %lx, bl_size %lx\n",
                  (ulong)preamble->body_load_address,
                  (ulong)preamble->bootloader_address,
@@ -189,12 +188,13 @@ static int cros_read_bootflow(struct udevice *dev, struct bootflow *bflow)
                       num_blks, buf);
        if (ret != num_blks)
                return log_msg_ret("inf", -EIO);
-       base = map_to_sysmem(buf);
+       base = map_to_sysmem(buf) + preamble->bootloader_address -
+               preamble->body_load_address;
 
-       setup = base + start - OFFSET_BASE - SETUP_OFFSET;
-       cmdline = base + start - OFFSET_BASE - CMDLINE_OFFSET;
-       kern_base = base + start - OFFSET_BASE + SZ_16K;
-       log_debug("base %lx setup %lx, cmdline %lx, kern_base %lx\n", base,
+       setup = base + X86_SETUP_OFFSET;
+       cmdline = base + CMDLINE_OFFSET;
+       kern_base = base + X86_KERNEL_OFFSET;
+       log_debug("base %lx setup %lx cmdline %lx kern_base %lx\n", base,
                  setup, cmdline, kern_base);
 
 #ifdef CONFIG_X86