[PATCH v3 1/7] acpi: Add early device probing infrastructure

On Fri, 2 Oct 2015 16:06:05 -0500
Wei Huang [off-list ref] wrote:

Hi Wei,

Hi Marc,

[...]

quoted

+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.

quoted

+	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.