[RFC PATCH v2 5/9] lib: irqchip/plic: Add context save/restore helpers

[Anup Patel]

On Mon, May 30, 2022 at 9:07 AM Samuel Holland <samuel at sholland.org> wrote:
>
> These can be used by platform code to save the PLIC context state, if
> it would otherwise be lost during non-retentive suspend. The platform
> is responsible for allocating all necessary storage.
>
> Signed-off-by: Samuel Holland <samuel at sholland.org>

Looks good to me.

Reviewed-by: Anup Patel <anup at brainfault.org>

Regards,
Anup

> ---
>
> Changes in v2:
>  - New patch for v2
>
>  include/sbi_utils/irqchip/plic.h |  6 ++++
>  lib/utils/irqchip/plic.c         | 51 ++++++++++++++++++++++++++++++--
>  2 files changed, 54 insertions(+), 3 deletions(-)
>
> diff --git a/include/sbi_utils/irqchip/plic.h b/include/sbi_utils/irqchip/plic.h
> index 8f21af6..21b2266 100644
> --- a/include/sbi_utils/irqchip/plic.h
> +++ b/include/sbi_utils/irqchip/plic.h
> @@ -17,6 +17,12 @@ struct plic_data {
>         unsigned long num_src;
>  };
>
> +void plic_context_save(const struct plic_data *plic, int context_id,
> +                      u32 *enable, u32 *threshold);
> +
> +void plic_context_restore(const struct plic_data *plic, int context_id,
> +                         const u32 *enable, u32 threshold);
> +
>  int plic_context_init(const struct plic_data *plic, int context_id,
>                       bool enable, u32 threshold);
>
> diff --git a/lib/utils/irqchip/plic.c b/lib/utils/irqchip/plic.c
> index 9bd3bf1..0c64078 100644
> --- a/lib/utils/irqchip/plic.c
> +++ b/lib/utils/irqchip/plic.c
> @@ -29,6 +29,16 @@ static void plic_set_priority(const struct plic_data *plic, u32 source, u32 val)
>         writel(val, plic_priority);
>  }
>
> +static u32 plic_get_thresh(const struct plic_data *plic, u32 cntxid)
> +{
> +       volatile void *plic_thresh;
> +
> +       plic_thresh = (char *)plic->addr +
> +                     PLIC_CONTEXT_BASE + PLIC_CONTEXT_STRIDE * cntxid;
> +
> +       return readl(plic_thresh);
> +}
> +
>  static void plic_set_thresh(const struct plic_data *plic, u32 cntxid, u32 val)
>  {
>         volatile void *plic_thresh;
> @@ -38,14 +48,49 @@ static void plic_set_thresh(const struct plic_data *plic, u32 cntxid, u32 val)
>         writel(val, plic_thresh);
>  }
>
> +static u32 plic_get_ie(const struct plic_data *plic, u32 cntxid,
> +                      u32 word_index)
> +{
> +       volatile void *plic_ie;
> +
> +       plic_ie = (char *)plic->addr +
> +                  PLIC_ENABLE_BASE + PLIC_ENABLE_STRIDE * cntxid +
> +                  4 * word_index;
> +
> +       return readl(plic_ie);
> +}
> +
>  static void plic_set_ie(const struct plic_data *plic, u32 cntxid,
>                         u32 word_index, u32 val)
>  {
> -       volatile char *plic_ie;
> +       volatile void *plic_ie;
>
>         plic_ie = (char *)plic->addr +
> -                  PLIC_ENABLE_BASE + PLIC_ENABLE_STRIDE * cntxid;
> -       writel(val, plic_ie + word_index * 4);
> +                  PLIC_ENABLE_BASE + PLIC_ENABLE_STRIDE * cntxid +
> +                  4 * word_index;
> +       writel(val, plic_ie);
> +}
> +
> +void plic_context_save(const struct plic_data *plic, int context_id,
> +                      u32 *enable, u32 *threshold)
> +{
> +       u32 ie_words = (plic->num_src + 31) / 32;
> +
> +       for (u32 i = 0; i < ie_words; i++)
> +               enable[i] = plic_get_ie(plic, context_id, i);
> +
> +       *threshold = plic_get_thresh(plic, context_id);
> +}
> +
> +void plic_context_restore(const struct plic_data *plic, int context_id,
> +                         const u32 *enable, u32 threshold)
> +{
> +       u32 ie_words = (plic->num_src + 31) / 32;
> +
> +       for (u32 i = 0; i < ie_words; i++)
> +               plic_set_ie(plic, context_id, i, enable[i]);
> +
> +       plic_set_thresh(plic, context_id, threshold);
>  }
>
>  int plic_context_init(const struct plic_data *plic, int context_id,
> --
> 2.35.1
>
>
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