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: Anup Patel <anup@brainfault.org>
7f09fba86e