On Thu, Dec 28, 2023 at 01:36:54PM +0000, Simon Glass wrote:
> Standard passage provides for a bloblist to be passed from one firmware
> phase to the next. That can be used to pass the devicetree along as well.
> Add an option to support this.
>
> Tests for this will be added as part of the Universal Payload work.
>
> Signed-off-by: Simon Glass <s...@chromium.org>
> ---
> The discussion on this was not resolved and is now important due to the
> bloblist series from Raymond. So I am sending it again since I believe
> this is a better starting point than building on OF_BOARD
[snip]
> @@ -1662,23 +1667,42 @@ static void setup_multi_dtb_fit(void)
>
> int fdtdec_setup(void)
> {
> - int ret;
> + int ret = -ENOENT;
> +
> + /* If allowing a bloblist, check that first */
> + if (CONFIG_IS_ENABLED(OF_BLOBLIST)) {
> + ret = bloblist_maybe_init();
> + if (!ret) {
> + gd->fdt_blob = bloblist_find(BLOBLISTT_CONTROL_FDT, 0);
> + if (gd->fdt_blob) {
> + gd->fdt_src = FDTSRC_BLOBLIST;
> + log_debug("Devicetree is in bloblist at %p\n",
> + gd->fdt_blob);
> + } else {
> + log_debug("No FDT found in bloblist\n");
> + ret = -ENOENT;
> + }
> + }
> + }
>
> - /* The devicetree is typically appended to U-Boot */
> - if (IS_ENABLED(CONFIG_OF_SEPARATE)) {
> - gd->fdt_blob = fdt_find_separate();
> - gd->fdt_src = FDTSRC_SEPARATE;
> - } else { /* embed dtb in ELF file for testing / development */
> - gd->fdt_blob = dtb_dt_embedded();
> - gd->fdt_src = FDTSRC_EMBED;
> + /* Otherwise, the devicetree is typically appended to U-Boot */
> + if (ret) {
> + if (IS_ENABLED(CONFIG_OF_SEPARATE)) {
> + gd->fdt_blob = fdt_find_separate();
> + gd->fdt_src = FDTSRC_SEPARATE;
> + } else { /* embed dtb in ELF file for testing / development */
> + gd->fdt_blob = dtb_dt_embedded();
> + gd->fdt_src = FDTSRC_EMBED;
> + }
> }This whole if/else tree looks wrong today, and then wrong with this patch. If we have an embedded device tree, which should only be used for development (or special case needs, I _think_ some users today are using this for security type needs), it must win and be used. The over-ride switch was set, and should be used. Then, I don't know if we should be saying "the user provided a tree via OF_SEPARATE, it should be used" or "the device has passed us a tree via standard mechanism, it should be used" is the higher priority. I really don't know which is more valid. -- Tom
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