From patchwork Sat Mar 14 00:11:29 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Atish Patra X-Patchwork-Id: 243628 List-Id: U-Boot discussion From: atish.patra at wdc.com (Atish Patra) Date: Fri, 13 Mar 2020 17:11:29 -0700 Subject: [PATCH v2 1/4] riscv: Add boot hartid to Device tree In-Reply-To: <20200314001132.17393-1-atish.patra@wdc.com> References: <20200314001132.17393-1-atish.patra@wdc.com> Message-ID: <20200314001132.17393-2-atish.patra@wdc.com> Linux booting protocol mandates that register "a0" contains the hartid. However, U-boot can not pass the hartid via a0 during via standard UEFI 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 Reviewed-by: Rick Chen --- 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; + } + 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; + } + } + + /* Overwrite the boot-hartid as U-Boot is the last state BL */ + fdt_setprop_u32(blob, chosen_offset, "boot-hartid", + gd->arch.boot_hart); + return 0; }