[U-Boot] [PATCH 1/2] fit: Support FDT compression

[Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>]

Hi Julius,

On Thu, Apr 18, 2019 at 10:13 AM Julius Werner <jwerner@chromium.org> wrote:
>
> This patch adds support for compressing FDT image nodes in a FIT image
> (equivalent to how kernel nodes can already be compressed). This can
> reduce the size of FIT images (and therefore improve boot times). FDTs
> will automatically get decompressed on load.
>
> This patch does not support extracting compatible strings from
> compressed FDTs, so it's not very helpful in conjunction with
> CONFIG_FIT_BEST_MATCH yet, but it can already be used in environments
> that select the configuration to load explicitly.
>
> Signed-off-by: Julius Werner <jwerner@chromium.org>

I was working on a patch that allows *all* items loaded from a FIT image to
be compressed. This is especially useful on my platform where FPGA images
(quite big) are embedded in the FIT image.

I think it would make more sense to make the decompression more generic
instead of adding yet another specific case for FDT decompression.

Unfortunately, I haven't found the time to finish my patch for this, yet...

Regards,
Simon

> ---
>  common/image-fit.c | 85 +++++++++++++++++++++++++++-------------------
>  1 file changed, 51 insertions(+), 34 deletions(-)
>
> diff --git a/common/image-fit.c b/common/image-fit.c
> index ac901e131c..20e02d240b 100644
> --- a/common/image-fit.c
> +++ b/common/image-fit.c
> @@ -22,6 +22,7 @@
>  DECLARE_GLOBAL_DATA_PTR;
>  #endif /* !USE_HOSTCC*/
>
> +#include <bootm.h>
>  #include <image.h>
>  #include <bootstage.h>
>  #include <u-boot/crc.h>
> @@ -1576,6 +1577,13 @@ int fit_conf_find_compat(const void *fit, const void *fdt)
>                               kfdt_name);
>                         continue;
>                 }
> +
> +               if (!fit_image_check_comp(fit, kfdt_noffset, IH_COMP_NONE)) {
> +                       debug("Can't extract compat from \"%s\" (compressed)\n",
> +                             kfdt_name);
> +                       continue;
> +               }
> +
>                 /*
>                  * Get a pointer to this configuration's fdt.
>                  */
> @@ -1795,11 +1803,12 @@ int fit_image_load(bootm_headers_t *images, ulong addr,
>         const char *fit_uname_config;
>         const char *fit_base_uname_config;
>         const void *fit;
> -       const void *buf;
> +       void *buf;
> +       void *loadbuf;
>         size_t size;
>         int type_ok, os_ok;
> -       ulong load, data, len;
> -       uint8_t os;
> +       ulong load, load_end, data, len;
> +       uint8_t os, comp;
>  #ifndef USE_HOSTCC
>         uint8_t os_arch;
>  #endif
> @@ -1895,12 +1904,6 @@ int fit_image_load(bootm_headers_t *images, ulong addr,
>         images->os.arch = os_arch;
>  #endif
>
> -       if (image_type == IH_TYPE_FLATDT &&
> -           !fit_image_check_comp(fit, noffset, IH_COMP_NONE)) {
> -               puts("FDT image is compressed");
> -               return -EPROTONOSUPPORT;
> -       }
> -
>         bootstage_mark(bootstage_id + BOOTSTAGE_SUB_CHECK_ALL);
>         type_ok = fit_image_check_type(fit, noffset, image_type) ||
>                   fit_image_check_type(fit, noffset, IH_TYPE_FIRMWARE) ||
> @@ -1931,7 +1934,8 @@ int fit_image_load(bootm_headers_t *images, ulong addr,
>         bootstage_mark(bootstage_id + BOOTSTAGE_SUB_CHECK_ALL_OK);
>
>         /* get image data address and length */
> -       if (fit_image_get_data_and_size(fit, noffset, &buf, &size)) {
> +       if (fit_image_get_data_and_size(fit, noffset,
> +                                       (const void **)&buf, &size)) {
>                 printf("Could not find %s subimage data!\n", prop_name);
>                 bootstage_error(bootstage_id + BOOTSTAGE_SUB_GET_DATA);
>                 return -ENOENT;
> @@ -1939,30 +1943,15 @@ int fit_image_load(bootm_headers_t *images, ulong addr,
>
>  #if !defined(USE_HOSTCC) && defined(CONFIG_FIT_IMAGE_POST_PROCESS)
>         /* perform any post-processing on the image data */
> -       board_fit_image_post_process((void **)&buf, &size);
> +       board_fit_image_post_process(&buf, &size);
>  #endif
>
>         len = (ulong)size;
>
> -       /* verify that image data is a proper FDT blob */
> -       if (image_type == IH_TYPE_FLATDT && fdt_check_header(buf)) {
> -               puts("Subimage data is not a FDT");
> -               return -ENOEXEC;
> -       }
> -
>         bootstage_mark(bootstage_id + BOOTSTAGE_SUB_GET_DATA_OK);
>
> -       /*
> -        * Work-around for eldk-4.2 which gives this warning if we try to
> -        * cast in the unmap_sysmem() call:
> -        * warning: initialization discards qualifiers from pointer target type
> -        */
> -       {
> -               void *vbuf = (void *)buf;
> -
> -               data = map_to_sysmem(vbuf);
> -       }
> -
> +       data = map_to_sysmem(buf);
> +       load = data;
>         if (load_op == FIT_LOAD_IGNORED) {
>                 /* Don't load */
>         } else if (fit_image_get_load(fit, noffset, &load)) {
> @@ -1974,8 +1963,6 @@ int fit_image_load(bootm_headers_t *images, ulong addr,
>                 }
>         } else if (load_op != FIT_LOAD_OPTIONAL_NON_ZERO || load) {
>                 ulong image_start, image_end;
> -               ulong load_end;
> -               void *dst;
>
>                 /*
>                  * move image data to the load address,
> @@ -1993,14 +1980,44 @@ int fit_image_load(bootm_headers_t *images, ulong addr,
>
>                 printf("   Loading %s from 0x%08lx to 0x%08lx\n",
>                        prop_name, data, load);
> +       }
>
> -               dst = map_sysmem(load, len);
> -               memmove(dst, buf, len);
> -               data = load;
> +       /*
> +        * Decompress FDTs right here. Kernel images get decompressed later in
> +        * bootm_host_load_image().
> +        */
> +       comp = IH_COMP_NONE;
> +       loadbuf = buf;
> +       if (image_type == IH_TYPE_FLATDT &&
> +           !fit_image_get_comp(fit, noffset, &comp) &&
> +           comp != IH_COMP_NONE) {
> +               ulong max_decomp_len = len * 20;
> +               if (load == data) {
> +                       loadbuf = malloc(max_decomp_len);
> +                       load = map_to_sysmem(loadbuf);
> +               } else {
> +                       loadbuf = map_sysmem(load, max_decomp_len);
> +               }
> +               if (bootm_decomp_image(comp, load, data, IH_TYPE_FLATDT,
> +                               loadbuf, buf, len, max_decomp_len, &load_end)) {
> +                       printf("Error: Cannot decompress FDT image\n");
> +                       return -ENOEXEC;
> +               }
> +               len = load_end - load;
> +       } else if (load != data) {
> +               loadbuf = map_sysmem(load, len);
> +               memcpy(loadbuf, buf, len);
>         }
> +
> +       /* verify that image data is a proper FDT blob */
> +       if (image_type == IH_TYPE_FLATDT && fdt_check_header(loadbuf)) {
> +               puts("Subimage data is not a FDT");
> +               return -ENOEXEC;
> +       }
> +
>         bootstage_mark(bootstage_id + BOOTSTAGE_SUB_LOAD);
>
> -       *datap = data;
> +       *datap = load;
>         *lenp = len;
>         if (fit_unamep)
>                 *fit_unamep = (char *)fit_uname;
> --
> 2.20.1
>
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