generic: fix appended dtb support

Appended DTB support is mostly intended to be used on legacy systems,
but it is a valid feature that can be enabled for generic platform,
which currently doesn't support it - if selected, the appended DTB will
be ignored by the platform startup code.

During kernel startup, the appended DTB's location is stored in
fw_passed_dtb if the init code finds what appears to be a valid DTB.
Otherwise (if a0 == -2), a1 is stored in fw_passed_dtb, so either way it
will always point to either a user-passed DTB or built-in DTB.

Signed-off-by: Marcin Nowakowski <marcin.nowakowski@fungible.com>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: linux-mips@vger.kernel.org
This commit is contained in:
Marcin Nowakowski 2019-05-13 14:32:43 +02:00 committed by Paul Burton
parent e6308b6d35
commit 67eebf7213
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@ -43,14 +43,14 @@ void __init *plat_get_fdt(void)
/* Already set up */
return (void *)fdt;
if ((fw_arg0 == -2) && !fdt_check_header((void *)fw_arg1)) {
if ((fw_arg0 == -2) && !fdt_check_header((void *)fw_passed_dtb)) {
/*
* We booted using the UHI boot protocol, so we have been
* provided with the appropriate device tree for the board.
* Make use of it & search for any machine struct based upon
* the root compatible string.
*/
fdt = (void *)fw_arg1;
fdt = (void *)fw_passed_dtb;
for_each_mips_machine(check_mach) {
match = mips_machine_is_compatible(check_mach, fdt);