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kboot: Allow loading fdt from different sources

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Linux has /sys/firmware/fdt and /proc/device-tree to publish the dtb for
the system. The former has it all in one file, while the latter breaks
it out. Prefer the former since it's the more modern interface, but
retain both since I don't have a PS3 to test to see if its kernel is new
enough for /sys/firmware or not.

In addition, do the proper fixup.

Sponsored by:		Netflix
This commit is contained in:
Warner Losh 2022-12-08 22:07:52 -07:00
parent 1066a70e14
commit 111610316e
1 changed files with 20 additions and 6 deletions
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26
stand/kboot/kbootfdt.c
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@ -94,11 +94,26 @@ fdt_platform_load_dtb(void)
{
void *buffer;
size_t buflen = 409600;
int fd;
/*
* Should load /sys/firmware/fdt if it exists, otherwise we walk the
* tree from /proc/device-tree. The former is much easier than the
* latter and also the newer interface. But as long as we support the
* PS3 boot, we'll need the latter due to that kernel's age. It likely
* would be better to script the decision between the two, but that
* turns out to be tricky...
*/
buffer = malloc(buflen);
fdt_create_empty_tree(buffer, buflen);
add_node_to_fdt(buffer, "/proc/device-tree",
fdt_path_offset(buffer, "/"));
fd = host_open("/sys/firmware/fdt", O_RDONLY, 0);
if (fd != -1) {
buflen = host_read(fd, buffer, buflen);
close(fd);
} else {
fdt_create_empty_tree(buffer, buflen);
add_node_to_fdt(buffer, "/proc/device-tree",
fdt_path_offset(buffer, "/"));
}
fdt_arch_fixups(buffer);
fdt_pack(buffer);
@ -112,12 +127,11 @@ fdt_platform_load_dtb(void)
void
fdt_platform_load_overlays(void)
{
fdt_load_dtb_overlays(NULL);
}
void
fdt_platform_fixups(void)
{
fdt_apply_overlays();
}