arm64, irqchip/gic-v3, ACPI: Move MADT GICC enabled check into a helper

ACPI, irqchip and the architecture code all inspect the MADT
enabled bit for a GICC entry in the MADT.

The addition of an 'online capable' bit means all these sites need
updating.

Move the current checks behind a helper to make future updates easier.
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>
Acked-by: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Link: https://lore.kernel.org/r/E1quv5D-00AeNJ-U8@rmk-PC.armlinux.org.ukSigned-off-by: Catalin Marinas <catalin.marinas@arm.com>

arch/arm64/kernel/smp.c

@@ -520,7 +520,7 @@ acpi_map_gic_cpu_interface(struct acpi_madt_generic_interrupt *processor)
 {
 	u64 hwid = processor->arm_mpidr;
 
-	if (!(processor->flags & ACPI_MADT_ENABLED)) {
+	if (!acpi_gicc_is_usable(processor)) {
 		pr_debug("skipping disabled CPU entry with 0x%llx MPIDR\n", hwid);
 		return;
 	}

drivers/acpi/processor_core.c

@@ -90,7 +90,7 @@ static int map_gicc_mpidr(struct acpi_subtable_header *entry,
 	struct acpi_madt_generic_interrupt *gicc =
 	    container_of(entry, struct acpi_madt_generic_interrupt, header);
 
-	if (!(gicc->flags & ACPI_MADT_ENABLED))
+	if (!acpi_gicc_is_usable(gicc))
 		return -ENODEV;
 
 	/* device_declaration means Device object in DSDT, in the

drivers/irqchip/irq-gic-v3.c

@@ -2367,8 +2367,7 @@ gic_acpi_parse_madt_gicc(union acpi_subtable_headers *header,
 	u32 size = reg == GIC_PIDR2_ARCH_GICv4 ? SZ_64K * 4 : SZ_64K * 2;
 	void __iomem *redist_base;
 
-	/* GICC entry which has !ACPI_MADT_ENABLED is not unusable so skip */
-	if (!(gicc->flags & ACPI_MADT_ENABLED))
+	if (!acpi_gicc_is_usable(gicc))
 		return 0;
 
 	redist_base = ioremap(gicc->gicr_base_address, size);
@@ -2418,7 +2417,7 @@ static int __init gic_acpi_match_gicc(union acpi_subtable_headers *header,
 	 * If GICC is enabled and has valid gicr base address, then it means
 	 * GICR base is presented via GICC
 	 */
-	if ((gicc->flags & ACPI_MADT_ENABLED) && gicc->gicr_base_address) {
+	if (acpi_gicc_is_usable(gicc) && gicc->gicr_base_address) {
 		acpi_data.enabled_rdists++;
 		return 0;
 	}
@@ -2427,7 +2426,7 @@ static int __init gic_acpi_match_gicc(union acpi_subtable_headers *header,
 	 * It's perfectly valid firmware can pass disabled GICC entry, driver
 	 * should not treat as errors, skip the entry instead of probe fail.
 	 */
-	if (!(gicc->flags & ACPI_MADT_ENABLED))
+	if (!acpi_gicc_is_usable(gicc))
 		return 0;
 
 	return -ENODEV;
@@ -2486,8 +2485,7 @@ static int __init gic_acpi_parse_virt_madt_gicc(union acpi_subtable_headers *hea
 	int maint_irq_mode;
 	static int first_madt = true;
 
-	/* Skip unusable CPUs */
-	if (!(gicc->flags & ACPI_MADT_ENABLED))
+	if (!acpi_gicc_is_usable(gicc))
 		return 0;
 
 	maint_irq_mode = (gicc->flags & ACPI_MADT_VGIC_IRQ_MODE) ?

include/linux/acpi.h

@@ -256,6 +256,11 @@ acpi_table_parse_cedt(enum acpi_cedt_type id,
 int acpi_parse_mcfg (struct acpi_table_header *header);
 void acpi_table_print_madt_entry (struct acpi_subtable_header *madt);
 
+static inline bool acpi_gicc_is_usable(struct acpi_madt_generic_interrupt *gicc)
+{
+	return gicc->flags & ACPI_MADT_ENABLED;
+}
+
 /* the following numa functions are architecture-dependent */
 void acpi_numa_slit_init (struct acpi_table_slit *slit);