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SubjectRe: [PATCH v3 1/7] acpi: Add early device probing infrastructure
On Fri, 2 Oct 2015 16:06:05 -0500
Wei Huang <wei@redhat.com> wrote:

Hi Wei,

> Hi Marc,

[...]

> > +struct acpi_probe_entry {
> > + __u8 id[ACPI_TABLE_ID_LEN];
> > + __u8 type;
> > + acpi_probe_entry_validate_subtbl subtable_valid;
> > + union {
> > + acpi_tbl_table_handler probe_table;
> > + acpi_tbl_entry_handler probe_subtbl;
> > + };
>
> Could we avoid using union for probe_table & probe_subtbl? The benefit is that we don't need to do function casting below and compiler can automatically check the correctness.
>
> > + kernel_ulong_t driver_data;
> > +};
> > +
> > +#define ACPI_DECLARE_PROBE_ENTRY(table, name, table_id, subtable, valid, data, fn) \
> > + static const struct acpi_probe_entry __acpi_probe_##name \
> > + __used __section(__##table##_acpi_probe_table) \
> > + = { \
> > + .id = table_id, \
> > + .type = subtable, \
> > + .subtable_valid = valid, \
> > + .probe_table = (acpi_tbl_table_handler)fn, \
> > + .driver_data = data, \
> > + }
> > +
>
> Something like:
>
> #define ACPI_DECLARE_PROBE_ENTRY(table, name, table_id, subtable, valid, data, fn, subfn) \
> static const struct acpi_probe_entry __acpi_probe_##name \
> __used __section(__##table##_acpi_probe_table) \
> = { \
> .id = table_id, \
> .type = subtable, \
> .subtable_valid = valid, \
> .probe_table = fn, \
> .probe_subtbl = subfn, \
> .driver_data = data, \
> }
>
> Then in patch 3, you can define new entries as:
>
> IRQCHIP_ACPI_DECLARE(gic_v2, ACPI_MADT_TYPE_GENERIC_DISTRIBUTOR,
> gic_validate_dist, ACPI_MADT_GIC_VERSION_V2,
> NULL, gic_v2_acpi_init);
> IRQCHIP_ACPI_DECLARE(gic_v2_maybe, ACPI_MADT_TYPE_GENERIC_DISTRIBUTOR,
> gic_validate_dist, ACPI_MADT_GIC_VERSION_NONE,
> NULL, gic_v2_acpi_init);
>

That's exactly what I was trying to avoid. If you want to do that, do
it in the IRQCHIP_ACPI_DECLARE macro, as there is strictly no need for
this this NULL to appear here (MADT always matches by subtable).

Or even better, have two ACPI_DECLARE* that populate the probe entry in
a mutually exclusive way (either probe_table is set and both
valid/subtbl are NULL, or probe_table is NULL and the two other fields
are set).

Thanks,

M.
--
Jazz is not dead. It just smells funny.


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