[PATCH v3 04/17] x86: zboot: Move kernel-version code into a function

[Simon Glass]

To help reduce the size and complexity of load_zimage(), move the code
that reads the kernel version into a separate function. Update
get_boot_protocol() to allow printing the 'Magic signature' message only
once, under control of its callers.

Signed-off-by: Simon Glass <s...@chromium.org>
Reviewed-by: Wolfgang Wallner <wolfgang.wall...@br-automation.com>
Reviewed-by: Bin Meng <bmeng...@gmail.com>
---

(no changes since v1)

 arch/x86/lib/zimage.c | 43 +++++++++++++++++++++++++++----------------
 1 file changed, 27 insertions(+), 16 deletions(-)

diff --git a/arch/x86/lib/zimage.c b/arch/x86/lib/zimage.c
index 3c8081a48bb..b2c3daf225d 100644
--- a/arch/x86/lib/zimage.c
+++ b/arch/x86/lib/zimage.c
@@ -103,21 +103,23 @@ static int kernel_magic_ok(struct setup_header *hdr)
        }
 }
 
-static int get_boot_protocol(struct setup_header *hdr)
+static int get_boot_protocol(struct setup_header *hdr, bool verbose)
 {
        if (hdr->header == KERNEL_V2_MAGIC) {
-               printf("Magic signature found\n");
+               if (verbose)
+                       printf("Magic signature found\n");
                return hdr->version;
        } else {
                /* Very old kernel */
-               printf("Magic signature not found\n");
+               if (verbose)
+                       printf("Magic signature not found\n");
                return 0x0100;
        }
 }
 
 static int setup_device_tree(struct setup_header *hdr, const void *fdt_blob)
 {
-       int bootproto = get_boot_protocol(hdr);
+       int bootproto = get_boot_protocol(hdr, false);
        struct setup_data *sd;
        int size;
 
@@ -147,10 +149,24 @@ static int setup_device_tree(struct setup_header *hdr, 
const void *fdt_blob)
        return 0;
 }
 
+static const char *get_kernel_version(struct boot_params *params,
+                                     void *kernel_base)
+{
+       struct setup_header *hdr = &params->hdr;
+       int bootproto;
+
+       bootproto = get_boot_protocol(hdr, false);
+       if (bootproto < 0x0200 || hdr->setup_sects < 15)
+               return NULL;
+
+       return kernel_base + hdr->kernel_version + 0x200;
+}
+
 struct boot_params *load_zimage(char *image, unsigned long kernel_size,
                                ulong *load_addressp)
 {
        struct boot_params *setup_base;
+       const char *version;
        int setup_size;
        int bootproto;
        int big_image;
@@ -178,21 +194,16 @@ struct boot_params *load_zimage(char *image, unsigned 
long kernel_size,
                printf("Error: Setup is too large (%d bytes)\n", setup_size);
 
        /* determine boot protocol version */
-       bootproto = get_boot_protocol(hdr);
+       bootproto = get_boot_protocol(hdr, true);
 
        printf("Using boot protocol version %x.%02x\n",
               (bootproto & 0xff00) >> 8, bootproto & 0xff);
 
-       if (bootproto >= 0x0200) {
-               if (hdr->setup_sects >= 15) {
-                       printf("Linux kernel version %s\n",
-                               (char *)params +
-                               hdr->kernel_version + 0x200);
-               } else {
-                       printf("Setup Sectors < 15 - "
-                               "Cannot print kernel version.\n");
-               }
-       }
+       version = get_kernel_version(params, image);
+       if (version)
+               printf("Linux kernel version %s\n", version);
+       else
+               printf("Setup Sectors < 15 - Cannot print kernel version\n");
 
        /* Determine image type */
        big_image = (bootproto >= 0x0200) &&
@@ -261,7 +272,7 @@ int setup_zimage(struct boot_params *setup_base, char 
*cmd_line, int auto_boot,
                 unsigned long initrd_addr, unsigned long initrd_size)
 {
        struct setup_header *hdr = &setup_base->hdr;
-       int bootproto = get_boot_protocol(hdr);
+       int bootproto = get_boot_protocol(hdr, false);
 
        setup_base->e820_entries = install_e820_map(
                ARRAY_SIZE(setup_base->e820_map), setup_base->e820_map);
-- 
2.28.0.526.ge36021eeef-goog