u-boot/arch/riscv/lib/semihosting.c
Kautuk Consul ae3527f088 arch/riscv: add semihosting support for RISC-V
We add RISC-V semihosting based serial console for JTAG based early
debugging.

The RISC-V semihosting specification is available at:
https://github.com/riscv/riscv-semihosting-spec/blob/main/riscv-semihosting-spec.adoc

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Signed-off-by: Kautuk Consul <kconsul@ventanamicro.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>
2022-12-08 15:15:58 +08:00

24 lines
448 B
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2022 Ventana Micro Systems Inc.
*/
#include <common.h>
long smh_trap(int sysnum, void *addr)
{
register int ret asm ("a0") = sysnum;
register void *param0 asm ("a1") = addr;
asm volatile (".align 4\n"
".option push\n"
".option norvc\n"
"slli zero, zero, 0x1f\n"
"ebreak\n"
"srai zero, zero, 7\n"
".option pop\n"
: "+r" (ret) : "r" (param0) : "memory");
return ret;
}