Re: [PATCH v5 4/5] tty: Add SBI debug console support to HVC SBI driver

Andrew Jones
2023-11-24T17:31:41Z

On Fri, Nov 24, 2023 at 12:39:04PM +0530, Anup Patel wrote:
> From: Atish Patra <atishp@rivosinc.com>
>
> RISC-V SBI specification supports advanced debug console
> support via SBI DBCN extension.
>
> Extend the HVC SBI driver to support it.
>
> Signed-off-by: Atish Patra <atishp@rivosinc.com>
> Signed-off-by: Anup Patel <apatel@ventanamicro.com>
> ---
> drivers/tty/hvc/Kconfig | 2 +-
> drivers/tty/hvc/hvc_riscv_sbi.c | 37 ++++++++++++++++++++++++++-------
> 2 files changed, 31 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/tty/hvc/Kconfig b/drivers/tty/hvc/Kconfig
> index 4f9264d005c0..6e05c5c7bca1 100644
> --- a/drivers/tty/hvc/Kconfig
> +++ b/drivers/tty/hvc/Kconfig
> @@ -108,7 +108,7 @@ config HVC_DCC_SERIALIZE_SMP
>
> config HVC_RISCV_SBI
> bool "RISC-V SBI console support"
> - depends on RISCV_SBI_V01
> + depends on RISCV_SBI
> select HVC_DRIVER
> help
> This enables support for console output via RISC-V SBI calls, which
> diff --git a/drivers/tty/hvc/hvc_riscv_sbi.c b/drivers/tty/hvc/hvc_riscv_sbi.c
> index 31f53fa77e4a..2f3571f17ecd 100644
> --- a/drivers/tty/hvc/hvc_riscv_sbi.c
> +++ b/drivers/tty/hvc/hvc_riscv_sbi.c
> @@ -39,21 +39,44 @@ static int hvc_sbi_tty_get(uint32_t vtermno, char *buf, int count)
> return i;
> }
>
> -static const struct hv_ops hvc_sbi_ops = {
> +static const struct hv_ops hvc_sbi_v01_ops = {
> .get_chars = hvc_sbi_tty_get,
> .put_chars = hvc_sbi_tty_put,
> };
>
> -static int __init hvc_sbi_init(void)
> +static int hvc_sbi_dbcn_tty_put(uint32_t vtermno, const char *buf, int count)
> {
> - return PTR_ERR_OR_ZERO(hvc_alloc(0, 0, &hvc_sbi_ops, 16));
> + return sbi_debug_console_write(buf, count);
> }
> -device_initcall(hvc_sbi_init);
>
> -static int __init hvc_sbi_console_init(void)
> +static int hvc_sbi_dbcn_tty_get(uint32_t vtermno, char *buf, int count)
> {
> - hvc_instantiate(0, 0, &hvc_sbi_ops);
> + return sbi_debug_console_read(buf, count);
> +}
> +
> +static const struct hv_ops hvc_sbi_dbcn_ops = {
> + .put_chars = hvc_sbi_dbcn_tty_put,
> + .get_chars = hvc_sbi_dbcn_tty_get,
> +};
> +
> +static int __init hvc_sbi_init(void)
> +{
> + int err;
> +
> + if (sbi_debug_console_available) {
> + err = PTR_ERR_OR_ZERO(hvc_alloc(0, 0, &hvc_sbi_dbcn_ops, 256));
> + if (err)
> + return err;
> + hvc_instantiate(0, 0, &hvc_sbi_dbcn_ops);
> + } else if (IS_ENABLED(CONFIG_RISCV_SBI_V01)) {
> + err = PTR_ERR_OR_ZERO(hvc_alloc(0, 0, &hvc_sbi_v01_ops, 256));
> + if (err)
> + return err;
> + hvc_instantiate(0, 0, &hvc_sbi_v01_ops);
> + } else {
> + return -ENODEV;
> + }
>
> return 0;
> }
> -console_initcall(hvc_sbi_console_init);
> +device_initcall(hvc_sbi_init);
> --
> 2.34.1
>

Reviewed-by: Andrew Jones <ajones@ventanamicro.com>