[PATCH v6 4/7] lib: sbi: Only register available extensions

[Anup Patel]

On Mon, May 15, 2023 at 4:42 PM Andrew Jones <ajones at ventanamicro.com> wrote:
>
> When an extension implements a probe function it means there's a
> chance that the extension is not available. Use this function in the
> register_extensions callback to determine if the extension should be
> registered at all. Where the probe implementation is simple, just
> open code the check.
>
> Signed-off-by: Andrew Jones <ajones at ventanamicro.com>
> Reviewed-by: Anup Patel <anup at brainfault.org>

The sbi_ecall_init() needs to be called after sbi_platform_final_init()
so that platform devices registered by sbi_platform_final_init() can
be considered at the time of registering SBI extensions.

Applied this patch to the riscv/opensbi repo with above change
included.

Thanks,
Anup

> ---
>  lib/sbi/sbi_ecall_cppc.c   |  3 +++
>  lib/sbi/sbi_ecall_dbcn.c   |  3 +++
>  lib/sbi/sbi_ecall_srst.c   |  6 ++++++
>  lib/sbi/sbi_ecall_susp.c   |  6 ++++++
>  lib/sbi/sbi_ecall_vendor.c | 17 +++--------------
>  5 files changed, 21 insertions(+), 14 deletions(-)
>
> diff --git a/lib/sbi/sbi_ecall_cppc.c b/lib/sbi/sbi_ecall_cppc.c
> index 42ec744c22ba..a6398ac78226 100644
> --- a/lib/sbi/sbi_ecall_cppc.c
> +++ b/lib/sbi/sbi_ecall_cppc.c
> @@ -59,6 +59,9 @@ struct sbi_ecall_extension ecall_cppc;
>
>  static int sbi_ecall_cppc_register_extensions(void)
>  {
> +       if (!sbi_cppc_get_device())
> +               return 0;
> +
>         return sbi_ecall_register_extension(&ecall_cppc);
>  }
>
> diff --git a/lib/sbi/sbi_ecall_dbcn.c b/lib/sbi/sbi_ecall_dbcn.c
> index 58b19e4468ef..cbb2e802e615 100644
> --- a/lib/sbi/sbi_ecall_dbcn.c
> +++ b/lib/sbi/sbi_ecall_dbcn.c
> @@ -68,6 +68,9 @@ struct sbi_ecall_extension ecall_dbcn;
>
>  static int sbi_ecall_dbcn_register_extensions(void)
>  {
> +       if (!sbi_console_get_device())
> +               return 0;
> +
>         return sbi_ecall_register_extension(&ecall_dbcn);
>  }
>
> diff --git a/lib/sbi/sbi_ecall_srst.c b/lib/sbi/sbi_ecall_srst.c
> index ad31537604a3..ea0dc73f010d 100644
> --- a/lib/sbi/sbi_ecall_srst.c
> +++ b/lib/sbi/sbi_ecall_srst.c
> @@ -71,6 +71,12 @@ struct sbi_ecall_extension ecall_srst;
>
>  static int sbi_ecall_srst_register_extensions(void)
>  {
> +       unsigned long out_val;
> +
> +       sbi_ecall_srst_probe(SBI_EXT_SRST, &out_val);
> +       if (!out_val)
> +               return 0;
> +
>         return sbi_ecall_register_extension(&ecall_srst);
>  }
>
> diff --git a/lib/sbi/sbi_ecall_susp.c b/lib/sbi/sbi_ecall_susp.c
> index bfbdbe648625..c4124046b929 100644
> --- a/lib/sbi/sbi_ecall_susp.c
> +++ b/lib/sbi/sbi_ecall_susp.c
> @@ -44,6 +44,12 @@ struct sbi_ecall_extension ecall_susp;
>
>  static int sbi_ecall_susp_register_extensions(void)
>  {
> +       unsigned long out_val;
> +
> +       sbi_ecall_susp_probe(SBI_EXT_SUSP, &out_val);
> +       if (!out_val)
> +               return 0;
> +
>         return sbi_ecall_register_extension(&ecall_susp);
>  }
>
> diff --git a/lib/sbi/sbi_ecall_vendor.c b/lib/sbi/sbi_ecall_vendor.c
> index 39c58c8b6fd5..700f475f0a86 100644
> --- a/lib/sbi/sbi_ecall_vendor.c
> +++ b/lib/sbi/sbi_ecall_vendor.c
> @@ -22,24 +22,11 @@ static inline unsigned long sbi_ecall_vendor_id(void)
>                  (SBI_EXT_VENDOR_END - SBI_EXT_VENDOR_START));
>  }
>
> -static int sbi_ecall_vendor_probe(unsigned long extid,
> -                                 unsigned long *out_val)
> -{
> -       if (!sbi_platform_vendor_ext_check(sbi_platform_thishart_ptr()))
> -               *out_val = 0;
> -       else
> -               *out_val = 1;
> -       return 0;
> -}
> -
>  static int sbi_ecall_vendor_handler(unsigned long extid, unsigned long funcid,
>                                     const struct sbi_trap_regs *regs,
>                                     unsigned long *out_val,
>                                     struct sbi_trap_info *out_trap)
>  {
> -       if (!sbi_platform_vendor_ext_check(sbi_platform_thishart_ptr()))
> -               return SBI_ERR_NOT_SUPPORTED;
> -
>         return sbi_platform_vendor_ext_provider(sbi_platform_thishart_ptr(),
>                                                 funcid, regs,
>                                                 out_val, out_trap);
> @@ -51,6 +38,9 @@ static int sbi_ecall_vendor_register_extensions(void)
>  {
>         unsigned long extid = sbi_ecall_vendor_id();
>
> +       if (!sbi_platform_vendor_ext_check(sbi_platform_thishart_ptr()))
> +               return 0;
> +
>         ecall_vendor.extid_start = extid;
>         ecall_vendor.extid_end = extid;
>
> @@ -61,6 +51,5 @@ struct sbi_ecall_extension ecall_vendor = {
>         .extid_start            = SBI_EXT_VENDOR_START,
>         .extid_end              = SBI_EXT_VENDOR_END,
>         .register_extensions    = sbi_ecall_vendor_register_extensions,
> -       .probe                  = sbi_ecall_vendor_probe,
>         .handle                 = sbi_ecall_vendor_handler,
>  };
> --
> 2.40.0
>