On Fri, Apr 12, 2024 at 6:07 PM Rob Herring <robh@xxxxxxxxxx> wrote:
>
> On Fri, Apr 12, 2024 at 6:29 AM Anup Patel <apatel@xxxxxxxxxxxxxxxx> wrote:
> >
> > Some of the PCI controllers (such as generic PCI host controller)
> > use "interrupt-map" DT property to describe the mapping between
> > PCI endpoints and PCI interrupt pins.
>
> I would go as far as saying that's the only case as that's the only
> case where the interrupts are not described in DT.
Sure, I will update the text.
>
> > Currently, there is no fw_devlink created based on "interrupt-map"
> > DT property so interrupt controller is not guaranteed to be probed
> > before PCI host controller. This mainly affects RISC-V platforms
> > where both PCI host controller and interrupt controllers are probed
> > as regular platform devices.
>
> That's *every* system with PCI really.
Okay, I will re-word.
>
> > This creates fw_devlink between consumers (PCI host controller) and
> > supplier (interrupt controller) based on "interrupt-map" DT property.
> >
> > Signed-off-by: Anup Patel <apatel@xxxxxxxxxxxxxxxx>
> > ---
> > drivers/of/property.c | 53 +++++++++++++++++++++++++++++++++++++++++++
> > 1 file changed, 53 insertions(+)
> >
> > diff --git a/drivers/of/property.c b/drivers/of/property.c
> > index a6358ee99b74..ccbbb651a89a 100644
> > --- a/drivers/of/property.c
> > +++ b/drivers/of/property.c
> > @@ -1311,6 +1311,58 @@ static struct device_node *parse_interrupts(struct device_node *np,
> > return of_irq_parse_one(np, index, &sup_args) ? NULL : sup_args.np;
> > }
> >
> > +static struct device_node *parse_interrupt_map(struct device_node *np,
> > + const char *prop_name, int index)
> > +{
> > + struct device_node *tn, *ipar, *supnp = NULL;
> > + u32 addrcells, intcells, cells;
> > + const __be32 *imap, *imap_end;
> > + int i, imaplen;
> > +
> > + if (!IS_ENABLED(CONFIG_OF_IRQ))
> > + return NULL;
> > +
> > + if (strcmp(prop_name, "interrupt-map"))
> > + return NULL;
> > +
> > + ipar = of_node_get(np);
> > + do {
> > + if (!of_property_read_u32(ipar, "#interrupt-cells", &intcells))
> > + break;
> > + tn = ipar;
> > + ipar = of_irq_find_parent(ipar);
> > + of_node_put(tn);
> > + } while (ipar);
> > + if (!ipar)
> > + return NULL;
> > + addrcells = of_bus_n_addr_cells(ipar);
> > + of_node_put(ipar);
> > +
> > + imap = of_get_property(np, "interrupt-map", &imaplen);
> > + if (!imap || imaplen <= (addrcells + intcells))
> > + return NULL;
> > + imap_end = imap + imaplen;
> > +
> > + for (i = 0; i <= index && imap < imap_end; i++) {
> > + if (supnp)
> > + of_node_put(supnp);
> > +
> > + imap += addrcells;
> > + imap += intcells;
> > +
> > + supnp = of_find_node_by_phandle(be32_to_cpu(imap[0]));
> > + if (!supnp)
> > + return NULL;
> > + imap += 1;
> > +
> > + if (of_property_read_u32(supnp, "#interrupt-cells", &cells))
> > + return NULL;
> > + imap += cells;
>
> This is wrong. Technically, you can have #address-cells too.
>
> The bigger problem I have is this creates 2 sets of 'interrupt-map'
> parsing code. Your version skips a lot of things like whether the
> interrupt controller is available and there's the list of
> 'interrupt-map' abusers to think about.
>
In my first attempt, I was trying to keep it simple but I guess I
over-simplified it.
I have an alternate approach to use of_irq_parse_raw() over
here (similar to of_irq_parse_pci() in drivers/pci/of.c). Are you
okay with this approach ?
Regards,
Anup
