On Fri, Oct 20, 2023 at 12:51:39PM +0530, Anup Patel wrote:
> From: Atish Patra <atishp@xxxxxxxxxxxx>
>
> 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@xxxxxxxxxxxx>
> Signed-off-by: Anup Patel <apatel@xxxxxxxxxxxxxxxx>
> ---
> drivers/tty/hvc/Kconfig | 2 +-
> drivers/tty/hvc/hvc_riscv_sbi.c | 82 ++++++++++++++++++++++++++++++---
> 2 files changed, 76 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..56da1a4b5aca 100644
> --- a/drivers/tty/hvc/hvc_riscv_sbi.c
> +++ b/drivers/tty/hvc/hvc_riscv_sbi.c
> @@ -39,21 +39,89 @@ 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));
> + phys_addr_t pa;
> + struct sbiret ret;
> +
> + if (is_vmalloc_addr(buf)) {
> + pa = page_to_phys(vmalloc_to_page(buf)) + offset_in_page(buf);
> + if (PAGE_SIZE < (offset_in_page(buf) + count))
I thought checkpatch complained about uppercase constants being on the
left in comparisons.
> + count = PAGE_SIZE - offset_in_page(buf);
> + } else {
> + pa = __pa(buf);
> + }
> +
> + if (IS_ENABLED(CONFIG_32BIT))
> + ret = sbi_ecall(SBI_EXT_DBCN, SBI_EXT_DBCN_CONSOLE_WRITE,
> + count, lower_32_bits(pa), upper_32_bits(pa),
> + 0, 0, 0);
> + else
> + ret = sbi_ecall(SBI_EXT_DBCN, SBI_EXT_DBCN_CONSOLE_WRITE,
> + count, pa, 0, 0, 0, 0);
> + if (ret.error)
> + return 0;
> +
> + return count;
Shouldn't we return ret.value here in case it's less than count? I see we
already do that below in get().
> }
> -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);
> + phys_addr_t pa;
> + struct sbiret ret;
> +
> + if (is_vmalloc_addr(buf)) {
> + pa = page_to_phys(vmalloc_to_page(buf)) + offset_in_page(buf);
> + if (PAGE_SIZE < (offset_in_page(buf) + count))
> + count = PAGE_SIZE - offset_in_page(buf);
> + } else {
> + pa = __pa(buf);
> + }
> +
> + if (IS_ENABLED(CONFIG_32BIT))
> + ret = sbi_ecall(SBI_EXT_DBCN, SBI_EXT_DBCN_CONSOLE_READ,
> + count, lower_32_bits(pa), upper_32_bits(pa),
> + 0, 0, 0);
> + else
> + ret = sbi_ecall(SBI_EXT_DBCN, SBI_EXT_DBCN_CONSOLE_READ,
> + count, pa, 0, 0, 0, 0);
> + if (ret.error)
> + return 0;
> +
> + return ret.value;
> +}
> +
> +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_spec_version >= sbi_mk_version(2, 0)) &&
> + (sbi_probe_extension(SBI_EXT_DBCN) > 0)) {
> + err = PTR_ERR_OR_ZERO(hvc_alloc(0, 0, &hvc_sbi_dbcn_ops, 16));
Why an outbuf size of only 16?
> + 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, 16));
> + 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
>
Thanks,
drew
