spl: fit: Factor out FIT parsing and use a context struct

The logical steps in spl_load_simple_fit() are difficult to follow.
I think the long comments, ifdefs, and ungodly number of variables
seriously affect the readability. In particular, it violates section 6
of the coding style, paragraphs (3), and (4).

The purpose of this patch is to improve the situation by
  - Factoring out initialization and parsing to separate functions
  - Reduce the number of variables by using a context structure
This change introduces no functional changes.

Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

diff --git a/common/spl/spl_fit.c b/common/spl/spl_fit.c
index bf3731a6272d544944441cd8e79ee72ebfff26b7..91091b651b8be7848f9d002cdca5198175eaac86 100644 (file)
--- a/common/spl/spl_fit.c
+++ b/common/spl/spl_fit.c
@@ -27,6 +27,12 @@ DECLARE_GLOBAL_DATA_PTR;
 #define CONFIG_SYS_BOOTM_LEN   (64 << 20)
 #endif
 
+struct spl_fit_info {
+       const void *fit;        /* Pointer to a valid FIT blob */
+       size_t ext_data_offset; /* Offset to FIT external data (end of FIT) */
+       int images_node;        /* FDT offset to "/images" node */
+};
+
 __weak void board_spl_fit_post_load(const void *fit)
 {
 }
@@ -522,28 +528,22 @@ __weak bool spl_load_simple_fit_skip_processing(void)
        return false;
 }
 
-int spl_load_simple_fit(struct spl_image_info *spl_image,
-                       struct spl_load_info *info, ulong sector, void *fit)
+static int spl_simple_fit_read(struct spl_fit_info *ctx,
+                              struct spl_load_info *info, ulong sector,
+                              const void *fit_header)
 {
+       unsigned long count, size;
        int sectors;
-       ulong size, hsize;
-       unsigned long count;
-       struct spl_image_info image_info;
-       int node = -1;
-       int images, ret;
-       int base_offset;
-       int index = 0;
-       int firmware_node;
+       void *buf;
 
        /*
         * For FIT with external data, figure out where the external images
         * start. This is the base for the data-offset properties in each
         * image.
         */
-       size = fdt_totalsize(fit);
-       size = (size + 3) & ~3;
+       size = ALIGN(fdt_totalsize(fit_header), 4);
        size = board_spl_fit_size_align(size);
-       base_offset = (size + 3) & ~3;
+       ctx->ext_data_offset = ALIGN(size, 4);
 
        /*
         * So far we only have one block of data from the FIT. Read the entire
@@ -553,36 +553,66 @@ int spl_load_simple_fit(struct spl_image_info *spl_image,
         * For FIT with external data, data is not loaded in this step.
         */
        sectors = get_aligned_image_size(info, size, 0);
-       hsize = sectors * info->bl_len;
-       fit = spl_get_fit_load_buffer(hsize);
-       count = info->read(info, sector, sectors, fit);
-       debug("fit read sector %lx, sectors=%d, dst=%p, count=%lu, size=0x%lx\n",
-             sector, sectors, fit, count, size);
+       buf = spl_get_fit_load_buffer(sectors * info->bl_len);
 
-       if (count == 0)
-               return -EIO;
+       count = info->read(info, sector, sectors, buf);
+       ctx->fit = buf;
+       debug("fit read sector %lx, sectors=%d, dst=%p, count=%lu, size=0x%lx\n",
+             sector, sectors, buf, count, size);
 
-       /* skip further processing if requested to enable load-only use cases */
-       if (spl_load_simple_fit_skip_processing())
-               return 0;
+       return (count == 0) ? -EIO : 0;
+}
 
+static int spl_simple_fit_parse(struct spl_fit_info *ctx)
+{
        if (IS_ENABLED(CONFIG_SPL_FIT_SIGNATURE)) {
-               int conf_offset = fit_find_config_node(fit);
+               int conf_offset = fit_find_config_node(ctx->fit);
 
                printf("## Checking hash(es) for config %s ... ",
-                      fit_get_name(fit, conf_offset, NULL));
-               if (fit_config_verify(fit, conf_offset))
+                      fit_get_name(ctx->fit, conf_offset, NULL));
+               if (fit_config_verify(ctx->fit, conf_offset))
                        return -EPERM;
                puts("OK\n");
        }
 
        /* find the node holding the images information */
-       images = fdt_path_offset(fit, FIT_IMAGES_PATH);
-       if (images < 0) {
-               debug("%s: Cannot find /images node: %d\n", __func__, images);
-               return -1;
+       ctx->images_node = fdt_path_offset(ctx->fit, FIT_IMAGES_PATH);
+       if (ctx->images_node < 0) {
+               debug("%s: Cannot find /images node: %d\n", __func__,
+                     ctx->images_node);
+               return -EINVAL;
        }
 
+       return 0;
+}
+
+int spl_load_simple_fit(struct spl_image_info *spl_image,
+                       struct spl_load_info *info, ulong sector, void *fit)
+{
+       struct spl_image_info image_info;
+       struct spl_fit_info ctx;
+       int node = -1;
+       int images, ret;
+       int base_offset;
+       int index = 0;
+       int firmware_node;
+
+       ret = spl_simple_fit_read(&ctx, info, sector, fit);
+       if (ret < 0)
+               return ret;
+
+       /* skip further processing if requested to enable load-only use cases */
+       if (spl_load_simple_fit_skip_processing())
+               return 0;
+
+       ret = spl_simple_fit_parse(&ctx);
+       if (ret < 0)
+               return ret;
+
+       images = ctx.images_node;
+       fit = (void *)ctx.fit;
+       base_offset = ctx.ext_data_offset;
+
 #ifdef CONFIG_SPL_FPGA
        node = spl_fit_get_image_node(fit, images, "fpga", 0);
        if (node >= 0) {