[PATCH v4 1/8] lib: sbi_pmu: add callback for counter width

[Anup Patel]

On Thu, Mar 9, 2023 at 6:44 PM Mayuresh Chitale
<mchitale at ventanamicro.com> wrote:
>
> This patch adds a callback to fetch the number of bits implemented for a
> custom firmware counter. If the callback fails or is not implemented then
> width defaults to 63.
>
> Signed-off-by: Mayuresh Chitale <mchitale at ventanamicro.com>
> Reviewed-by: Atish Patra <atishp at rivosinc.com>
> Reviewed-by: Anup Patel <anup at brainfault.org>

Applied this patch to the riscv/opensbi repo.

Thanks,
Anup

> ---
>  include/sbi/sbi_pmu.h | 5 +++++
>  lib/sbi/sbi_pmu.c     | 6 ++++++
>  2 files changed, 11 insertions(+)
>
> diff --git a/include/sbi/sbi_pmu.h b/include/sbi/sbi_pmu.h
> index c365243..b3b75c1 100644
> --- a/include/sbi/sbi_pmu.h
> +++ b/include/sbi/sbi_pmu.h
> @@ -41,6 +41,11 @@ struct sbi_pmu_device {
>         bool (*fw_counter_match_code)(uint32_t counter_index,
>                                       uint32_t event_idx_code);
>
> +       /**
> +        * Fetch the max width of this counter in number of bits.
> +        */
> +       int (*fw_counter_width)(void);
> +
>         /**
>          * Read value of custom firmware counter
>          * Note: 0 <= counter_index < SBI_PMU_FW_CTR_MAX
> diff --git a/lib/sbi/sbi_pmu.c b/lib/sbi/sbi_pmu.c
> index 154dbda..a99c045 100644
> --- a/lib/sbi/sbi_pmu.c
> +++ b/lib/sbi/sbi_pmu.c
> @@ -761,6 +761,7 @@ unsigned long sbi_pmu_num_ctr(void)
>
>  int sbi_pmu_ctr_get_info(uint32_t cidx, unsigned long *ctr_info)
>  {
> +       int width;
>         union sbi_pmu_ctr_info cinfo = {0};
>         struct sbi_scratch *scratch = sbi_scratch_thishart_ptr();
>
> @@ -782,6 +783,11 @@ int sbi_pmu_ctr_get_info(uint32_t cidx, unsigned long *ctr_info)
>                 cinfo.type = SBI_PMU_CTR_TYPE_FW;
>                 /* Firmware counters are always 64 bits wide */
>                 cinfo.width = 63;
> +               if (pmu_dev && pmu_dev->fw_counter_width) {
> +                       width = pmu_dev->fw_counter_width();
> +                       if (width)
> +                               cinfo.width = width - 1;
> +               }
>         }
>
>         *ctr_info = cinfo.value;
> --
> 2.34.1
>