[PATCH v2 1/3] lib: sbi: print before sbi_console_init

[Anup Patel]

On Mon, Jun 24, 2024 at 7:49 PM Xiang W <wxjstz at 126.com> wrote:
>
> The information from the print is cached via a ring buffer and
> output to the console after initialization is complete.
>
> Signed-off-by: Xiang W <wxjstz at 126.com>
> ---
>  lib/sbi/sbi_console.c | 29 +++++++++++++++++++++++++++++
>  1 file changed, 29 insertions(+)
>
> diff --git a/lib/sbi/sbi_console.c b/lib/sbi/sbi_console.c
> index d3ec461..1a91f88 100644
> --- a/lib/sbi/sbi_console.c
> +++ b/lib/sbi/sbi_console.c
> @@ -19,6 +19,8 @@
>  static const struct sbi_console_device *console_dev = NULL;
>  static char console_tbuf[CONSOLE_TBUF_MAX];
>  static u32 console_tbuf_len;
> +static u32 console_tbuf_stat;
> +static u32 console_tbuf_i;
>  static spinlock_t console_out_lock            = SPIN_LOCK_INITIALIZER;
>
>  bool sbi_isprintable(char c)
> @@ -135,6 +137,24 @@ static void printc(char **out, u32 *out_len, char ch, int flags)
>                 return;
>         }
>
> +       /* early print before sbi_console_init */
> +       if (!console_dev && (flags & USE_TBUF)) {
> +               /*
> +                * console_tbuf_stat
> +                *   0 buff is empty
> +                *   1 buff is not empty and does not overflow
> +                *   2 buff is overflow
> +                */
> +               console_tbuf [console_tbuf_i++] = ch;
> +               if (console_tbuf_stat == 0)
> +                       console_tbuf_stat = 1;
> +               if (console_tbuf_i == CONSOLE_TBUF_MAX) {
> +                       console_tbuf_stat = 2;
> +                       console_tbuf_i = 0;
> +               }
> +               return;
> +       }
> +

Repurposing console_tbuf for caching early prints is only
going to make things complicated for maintenance. The
console_tbuf is only for temporarily caching in print() function
so that we can provide multiple characters to console_dev
in one call.

Himanshu had suggested implementing a common circular
buffer but I don't see that in this series.

I have an alternate series ready which incorporates both
my suggestions and Himanshu's suggestions. I will post
that soon.

Regards,
Anup


>         /*
>          * The *printf entry point functions have enforced that (*out) can
>          * only be null when out_len is non-null and its value is zero.
> @@ -476,6 +496,15 @@ void sbi_console_set_device(const struct sbi_console_device *dev)
>                 return;
>
>         console_dev = dev;
> +
> +       if (console_tbuf_stat == 2)
> +               sbi_nputs(console_tbuf + console_tbuf_i,
> +                               CONSOLE_TBUF_MAX - console_tbuf_i);
> +       if (console_tbuf_stat)
> +               sbi_nputs(console_tbuf, console_tbuf_i);
> +
> +       console_tbuf_stat = 0;
> +       console_tbuf_i = 0;
>  }
>
>  int sbi_console_init(struct sbi_scratch *scratch)
> --
> 2.43.0
>