On Wed, Mar 18, 2020 at 5:19 AM Atish Patra <atish.pa...@wdc.com> wrote: > > Linux booting protocol mandates that register "a0" contains the hartid. > However, U-boot can not pass the hartid via a0 during via standard UEFI
nits: U-Boot remove "during" ? > protocol. DT nodes are commonly used to pass such information to the OS. > > Add a DT node under chosen node to indicate the boot hartid. EFI stub > in Linux kernel will parse this node and pass it to the real kernel > in "a0" before jumping to it. > > Signed-off-by: Atish Patra <atish.pa...@wdc.com> > Reviewed-by: Rick Chen <r...@andestech.com> > --- > arch/riscv/lib/bootm.c | 22 ++++++++++++++++++++++ > 1 file changed, 22 insertions(+) > > diff --git a/arch/riscv/lib/bootm.c b/arch/riscv/lib/bootm.c > index fad16901c5f2..f927694ae32f 100644 > --- a/arch/riscv/lib/bootm.c > +++ b/arch/riscv/lib/bootm.c > @@ -28,6 +28,28 @@ __weak void board_quiesce_devices(void) > > int arch_fixup_fdt(void *blob) > { > + u32 size; > + int chosen_offset, err; > + > + size = fdt_totalsize(blob); > + err = fdt_open_into(blob, blob, size + 32); > + if (err < 0) { > + printf("Device Tree can't be expanded to accommodate new > node"); > + return -1; return err > + } > + chosen_offset = fdt_path_offset(blob, "/chosen"); > + if (chosen_offset < 0) { > + err = fdt_add_subnode(blob, 0, "chosen"); > + if (err < 0) { > + printf("chosen node can not be added\n"); > + return -1; return err > + } > + } > + > + /* Overwrite the boot-hartid as U-Boot is the last state BL */ typo: stage > + fdt_setprop_u32(blob, chosen_offset, "boot-hartid", > + gd->arch.boot_hart); > + > return 0; > } > > -- Regards, Bin