Re: [PATCH v2 1/3] lib: utils: irqchip: implement APLIC hwirq operation hooks

Hi Ray,

On Mon, May 4, 2026 at 10:43 PM Raymond Mao <[email protected]> wrote:
>
> From: Raymond Mao <[email protected]>
>
> Implement the APLIC hardware interrupt hooks used by the generic
> irqchip framework for M-mode direct-mode wired interrupts.
>
> Program a minimal APLIC direct-mode configuration during hwirq setup
> and claim external interrupts via IDC.CLAIMI. Add the helper logic
> needed to derive the source ID from CLAIMI, map hart index to IDC
> index, skip delegated interrupts, and register process_hwirqs()
> only for the M-mode direct-mode provider.
>
> Signed-off-by: Raymond Mao <[email protected]>

Pawandeep Oza (CC'ed) has developed functionally complete IMSIC
and APLIC drivers for OpenSBI which supports both MSI-mode and
Direct-mode of APLIC. He did include some of your changes from
this patch. He will send-out his series pretty soon so stay tuned.

Regards,
Anup

> ---
>  lib/utils/irqchip/aplic.c | 227 ++++++++++++++++++++++++++++++++++++++
>  1 file changed, 227 insertions(+)
>
> diff --git a/lib/utils/irqchip/aplic.c b/lib/utils/irqchip/aplic.c
> index ec69c82b..3f4991b5 100644
> --- a/lib/utils/irqchip/aplic.c
> +++ b/lib/utils/irqchip/aplic.c
> @@ -245,6 +245,220 @@ static int aplic_check_msicfg(struct aplic_msicfg_data *msicfg)
>         return 0;
>  }
>
> +static inline void *aplic_idc_base(unsigned long aplic_addr, u32 idc_index)
> +{
> +       return (void *)(aplic_addr + APLIC_IDC_BASE +
> +                       (unsigned long)idc_index * APLIC_IDC_SIZE);
> +}
> +
> +static inline struct aplic_data *aplic_irqchip_to_data(struct sbi_irqchip_device *chip)
> +{
> +       return container_of(chip, struct aplic_data, irqchip);
> +}
> +
> +static bool aplic_hwirq_delegated(const struct aplic_data *aplic, u32 hwirq)
> +{
> +       u32 i;
> +
> +       for (i = 0; i < APLIC_MAX_DELEGATE; i++) {
> +               const struct aplic_delegate_data *deleg = &aplic->delegate[i];
> +
> +               if (!deleg->first_irq || !deleg->last_irq)
> +                       continue;
> +               if (deleg->first_irq <= hwirq && hwirq <= deleg->last_irq)
> +                       return true;
> +       }
> +
> +       return false;
> +}
> +
> +static bool aplic_mmode_direct(const struct aplic_data *aplic)
> +{
> +       return aplic->targets_mmode && aplic->num_idc;
> +}
> +
> +static int aplic_hartindex_to_idc_index(const struct aplic_data *aplic,
> +                                       u32 hartindex)
> +{
> +       u32 i;
> +
> +       if (!aplic->num_idc)
> +               return SBI_ENODEV;
> +
> +       if (aplic->idc_map) {
> +               for (i = 0; i < aplic->num_idc; i++) {
> +                       if (aplic->idc_map[i] == hartindex)
> +                               return i;
> +               }
> +
> +               return SBI_ENODEV;
> +       }
> +
> +       if (hartindex < aplic->num_idc)
> +               return hartindex;
> +
> +       return SBI_ENODEV;
> +}
> +
> +static int aplic_hwirq_target_idc_index(struct sbi_irqchip_device *chip)
> +{
> +       u32 hartindex = current_hartindex();
> +
> +       if (!sbi_hartmask_test_hartindex(hartindex, &chip->target_harts)) {
> +               sbi_hartmask_for_each_hartindex(hartindex, &chip->target_harts)
> +                       break;
> +               if (hartindex >= SBI_HARTMASK_MAX_BITS)
> +                       return SBI_ENODEV;
> +       }
> +
> +       return aplic_hartindex_to_idc_index(aplic_irqchip_to_data(chip),
> +                                           hartindex);
> +}
> +
> +static u32 aplic_domaincfg_value(void)
> +{
> +       u32 val = APLIC_DOMAINCFG_IE;
> +
> +#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
> +       val |= APLIC_DOMAINCFG_BE;
> +#endif
> +
> +       return val;
> +}
> +
> +static void aplic_hwirq_mask(struct sbi_irqchip_device *chip, u32 hwirq)
> +{
> +       struct aplic_data *aplic = aplic_irqchip_to_data(chip);
> +
> +       if (!hwirq || aplic_hwirq_delegated(aplic, hwirq))
> +               return;
> +
> +       if (!aplic->addr || hwirq > aplic->num_source)
> +               return;
> +
> +       /* Disable source */
> +       writel(hwirq, (void *)(aplic->addr + APLIC_CLRIENUM));
> +}
> +
> +static void aplic_hwirq_unmask(struct sbi_irqchip_device *chip, u32 hwirq)
> +{
> +       struct aplic_data *aplic = aplic_irqchip_to_data(chip);
> +
> +       if (!hwirq || aplic_hwirq_delegated(aplic, hwirq))
> +               return;
> +
> +       if (!aplic->addr || hwirq > aplic->num_source)
> +               return;
> +
> +       /* Enable source */
> +       writel(hwirq, (void *)(aplic->addr + APLIC_SETIENUM));
> +}
> +
> +static int aplic_hwirq_claim(struct sbi_irqchip_device *chip, u32 *hwirq)
> +{
> +       struct aplic_data *aplic = aplic_irqchip_to_data(chip);
> +       int idc_index;
> +       void *idc;
> +       u32 v, id;
> +
> +       if (!hwirq)
> +               return SBI_EINVAL;
> +
> +       idc_index = aplic_hartindex_to_idc_index(aplic, current_hartindex());
> +       if (!aplic->addr || idc_index < 0)
> +               return SBI_ENODEV;
> +
> +       idc = aplic_idc_base(aplic->addr, idc_index);
> +
> +       /*
> +        * Read CLAIMI: returns TOPI value.
> +        * ID==0 means spurious interrupt (spec-defined).
> +        */
> +       v = readl(idc + APLIC_IDC_CLAIMI); /* dequeue */
> +
> +       id = (v >> APLIC_IDC_TOPI_ID_SHIFT) & APLIC_IDC_TOPI_ID_MASK;
> +
> +       /* ID==0 means spurious / no pending wired interrupt */
> +       if (!id)
> +               return SBI_ENOENT;
> +
> +       /* Bound check against DT-discovered num_src */
> +       if (id > aplic->num_source)
> +               return SBI_EINVAL;
> +
> +       *hwirq = id;
> +
> +       return SBI_OK;
> +}
> +
> +static int aplic_hwirq_setup(struct sbi_irqchip_device *chip, u32 hwirq)
> +{
> +       struct aplic_data *aplic = aplic_irqchip_to_data(chip);
> +       unsigned long idc;
> +       int idc_index;
> +
> +       if (!hwirq || hwirq > aplic->num_source)
> +               return SBI_EINVAL;
> +       if (!aplic_mmode_direct(aplic))
> +               return SBI_ENOTSUPP;
> +       if (aplic_hwirq_delegated(aplic, hwirq))
> +               return SBI_ENOTSUPP;
> +
> +       idc_index = aplic_hwirq_target_idc_index(chip);
> +       if (idc_index < 0)
> +               return idc_index;
> +
> +       idc = aplic->addr + APLIC_IDC_BASE + idc_index * APLIC_IDC_SIZE;
> +
> +       /* APLIC: sourcecfg/target/enable */
> +       writel(APLIC_SOURCECFG_SM_LEVEL_HIGH,
> +              (void *)(aplic->addr + APLIC_SOURCECFG_BASE + (hwirq - 1) * 4));
> +
> +       writel(((u32)idc_index << APLIC_TARGET_HART_IDX_SHIFT) |
> +              APLIC_DEFAULT_PRIORITY,
> +              (void *)(aplic->addr + APLIC_TARGET_BASE + (hwirq - 1) * 4));
> +
> +       writel(hwirq, (void *)(aplic->addr + APLIC_SETIENUM));
> +
> +       /* Direct mode for aia=aplic: DM=0 => don't set DM bit */
> +       writel(aplic_domaincfg_value(), (void *)(aplic->addr + APLIC_DOMAINCFG));
> +
> +       /* IDC delivery */
> +       writel(APLIC_ENABLE_IDELIVERY, (void *)(idc + APLIC_IDC_IDELIVERY));
> +       writel(APLIC_ENABLE_ITHRESHOLD, (void *)(idc + APLIC_IDC_ITHRESHOLD));
> +
> +       return SBI_OK;
> +}
> +
> +static int aplic_process_hwirqs(struct sbi_irqchip_device *chip)
> +{
> +       if (!chip)
> +               return SBI_ENODEV;
> +
> +       for (;;) {
> +               u32 hwirq = 0;
> +               int rc = aplic_hwirq_claim(chip, &hwirq);
> +
> +               if (rc == SBI_ENOENT)
> +                       break;
> +               if (rc)
> +                       return rc;
> +
> +               if (!hwirq)
> +                       break;
> +
> +               if (hwirq > chip->num_hwirq) {
> +                       return SBI_EINVAL;
> +               }
> +
> +               rc = sbi_irqchip_process_hwirq(chip, hwirq);
> +               if (rc)
> +                       return rc;
> +       }
> +
> +       return SBI_OK;
> +}
> +
>  int aplic_cold_irqchip_init(struct aplic_data *aplic)
>  {
>         int rc;
> @@ -308,6 +522,19 @@ int aplic_cold_irqchip_init(struct aplic_data *aplic)
>         /* Register irqchip device */
>         aplic->irqchip.id = aplic->unique_id;
>         aplic->irqchip.num_hwirq = aplic->num_source + 1;
> +       aplic->irqchip.hwirq_mask = aplic_hwirq_mask;
> +       aplic->irqchip.hwirq_unmask = aplic_hwirq_unmask;
> +       /*
> +        * Only the domain that directly injects interrupts into M-mode external
> +        * interrupt line should provide process_hwirqs().
> +        *
> +        * The other domain (e.g. S-mode) may still be registered so that its
> +        * other ops (mask/unmask/config/etc.) can be used, but it must not
> +        * claim to be the external interrupt line provider.
> +        */
> +       if (aplic_mmode_direct(aplic))
> +               aplic->irqchip.process_hwirqs = aplic_process_hwirqs;
> +       aplic->irqchip.hwirq_setup = aplic_hwirq_setup;
>         rc = sbi_irqchip_add_device(&aplic->irqchip);
>         if (rc)
>                 return rc;
> --
> 2.25.1
>

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