Re: [PATCH v16 2/9] irqchip: Add RISC-V incoming MSI controller early driver

[Anup Patel]

On Fri, Apr 19, 2024 at 8:53 AM Eric Cheng <eric.cheng.linux@xxxxxxxxx> wrote:
>
> On 3/7/2024 10:03 PM, Anup Patel wrote:
>
> > +static int __init imsic_parse_fwnode(struct fwnode_handle *fwnode,
> > +                                  struct imsic_global_config *global,
> > +                                  u32 *nr_parent_irqs,
> > +                                  u32 *nr_mmios)
> > +{
>
> ...
>
> > +     /*
> > +      * Find first bit position of group index.
> > +      * If not specified assumed the default APLIC-IMSIC configuration.
> > +      */
> > +     rc = of_property_read_u32(to_of_node(fwnode), "riscv,group-index-shift",
> > +                               &global->group_index_shift);
> > +     if (rc)
> > +             global->group_index_shift = IMSIC_MMIO_PAGE_SHIFT * 2;
> > +
> > +     /* Find number of interrupt identities */
> > +     rc = of_property_read_u32(to_of_node(fwnode), "riscv,num-ids",
> > +                               &global->nr_ids);
>
> Will here check if the pass-in interrupt identity number is (multi-64 -1) &&
> between [63, 2047]?
> Per spec AIA v1.0, Sec. 3.1 Interrupt files and interrupt identities:
> "The number of interrupt identities supported by an interrupt file (and hence
> the number of active
> bits in each array) is one less than a multiple of 64, and may be a minimum of
> 63 and a maximum
> of 2047."

There is already a check on global->nr_ids to ensure the above is satisfied.
Please see further below in imsic_parse_fwnode() function.

>
> > +     if (rc) {
> > +             pr_err("%pfwP: number of interrupt identities not found\n", fwnode);
> > +             return rc;
> > +     }
> > +
> ...
>
>

Regards,
Anup