diff options
Diffstat (limited to 'firmware/payloads/dummy_head.S')
| -rw-r--r-- | firmware/payloads/dummy_head.S | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/firmware/payloads/dummy_head.S b/firmware/payloads/dummy_head.S new file mode 100644 index 0000000..1b36319 --- /dev/null +++ b/firmware/payloads/dummy_head.S @@ -0,0 +1,87 @@ +/* + * Copyright (c) 2018 Western Digital Corporation or its affiliates. + * + * Authors: + * Anup Patel <anup.patel@wdc.com> + * + * SPDX-License-Identifier: BSD-2-Clause + */ + +#define __ASM_STR(x) x + +#if __riscv_xlen == 64 +#define __REG_SEL(a, b) __ASM_STR(a) +#define RISCV_PTR .dword +#elif __riscv_xlen == 32 +#define __REG_SEL(a, b) __ASM_STR(b) +#define RISCV_PTR .word +#else +#error "Unexpected __riscv_xlen" +#endif + +#define REG_L __REG_SEL(ld, lw) +#define REG_S __REG_SEL(sd, sw) + + .align 3 + .section .entry, "ax", %progbits + .globl _start +_start: + /* Pick one hart to run the main boot sequence */ + la a3, _hart_lottery + li a2, 1 + amoadd.w a3, a2, (a3) + bnez a3, _start_hang + + /* Save a0 and a1 */ + la a3, _boot_a0 + REG_S a0, 0(a3) + la a3, _boot_a1 + REG_S a1, 0(a3) + + /* Zero-out BSS */ + la a4, _bss_start + la a5, _bss_end +_bss_zero: + REG_S zero, (a4) + add a4, a4, __SIZEOF_POINTER__ + blt a4, a5, _bss_zero + +_start_warm: + /* Disable and clear all interrupts */ + csrw sie, zero + csrw sip, zero + + /* Setup exception vectors */ + la a3, _start_hang + csrw stvec, a3 + + /* Setup stack */ + la a3, _payload_end + li a4, 0x2000 + add sp, a3, a4 + + /* Jump to C main */ + la a3, _boot_a0 + REG_L a0, 0(a3) + la a3, _boot_a1 + REG_L a1, 0(a3) + call dummy_main + + /* We don't expect to reach here hence just hang */ + j _start_hang + + .align 3 + .section .entry, "ax", %progbits + .globl _start_hang +_start_hang: + wfi + j _start_hang + + .align 3 + .section .entry, "ax", %progbits +_hart_lottery: + RISCV_PTR 0 +_boot_a0: + RISCV_PTR 0 +_boot_a1: + RISCV_PTR 0 |