tree c1c7d9166ae8d2ede7fa861d08b56be6ef459951
parent e72139e59db83da089b02b722e99e2446fc19709
author Samuel Holland <samuel@sholland.org> 1631462169 -0500
committer Leo Yu-Chi Liang <ycliang@andestech.com> 1633594103 +0800

serial: Add a debug console using the RISC-V SBI interface

The RISC-V SBI interface v0.1 provides a function for printing a
character to the console. Even though SBI v0.1 functions are deprecated,
the SBI console is quite useful for early debugging, because it works
without any dcache, memory, or MMIO access in S mode.

Signed-off-by: Samuel Holland <samuel@sholland.org>
Reviewed-by: Sean Anderson <seanga2@gmail.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>