ACPI: move arm64 GSI IRQ model to generic GSI IRQ layer

The code deployed to implement GSI linux IRQ numbers mapping on arm64 turns
out to be generic enough so that it can be moved to ACPI core code along
with its respective config option ACPI_GENERIC_GSI selectable on
architectures that can reuse the same code.

Current ACPI IRQ mapping code is not integrated in the kernel IRQ domain
infrastructure, in particular there is no way to look-up the
IRQ domain associated with a particular interrupt controller, so this
first version of GSI generic code carries out the GSI<->IRQ mapping relying
on the IRQ default domain which is supposed to be always set on a
specific architecture in case the domain structure passed to
irq_create/find_mapping() functions is missing.

This patch moves the arm64 acpi functions that implement the gsi mappings:

acpi_gsi_to_irq()
acpi_register_gsi()
acpi_unregister_gsi()

to ACPI core code. Since the generic GSI<->domain mapping is based on IRQ
domains, it can be extended as soon as a way to map an interrupt
controller to an IRQ domain is implemented for ACPI in the IRQ domain
layer.

x86 and ia64 code for GSI mappings cannot rely on the generic GSI
layer at present for legacy reasons, so they do not select the
ACPI_GENERIC_GSI config options and keep relying on their arch
specific GSI mapping layer.

Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Acked-by: Hanjun Guo <hanjun.guo@linaro.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

2 files changed, 1 insertions, 73 deletions

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index e5aa081b4845..0659db374731 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -1,5 +1,6 @@
 config ARM64
 	def_bool y
+	select ACPI_GENERIC_GSI if ACPI
 	select ACPI_REDUCED_HARDWARE_ONLY if ACPI
 	select ARCH_BINFMT_ELF_RANDOMIZE_PIE
 	select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
index fe9d8f0df4a3..a70f7141c0f6 100644
--- a/arch/arm64/kernel/acpi.c
+++ b/arch/arm64/kernel/acpi.c
@@ -76,12 +76,6 @@ static int __init dt_scan_depth1_nodes(unsigned long node,
 }
 
 /*
- * Since we're on ARM, the default interrupt routing model
- * clearly has to be GIC.
- */
-enum acpi_irq_model_id acpi_irq_model = ACPI_IRQ_MODEL_GIC;
-
-/*
  * __acpi_map_table() will be called before page_init(), so early_ioremap()
  * or early_memremap() should be called here to for ACPI table mapping.
  */
@@ -224,73 +218,6 @@ void __init acpi_init_cpus(void)
 	pr_info("%d CPUs enabled, %d CPUs total\n", enabled_cpus, total_cpus);
 }
 
-int acpi_gsi_to_irq(u32 gsi, unsigned int *irq)
-{
-	*irq = irq_find_mapping(NULL, gsi);
-
-	return 0;
-}
-EXPORT_SYMBOL_GPL(acpi_gsi_to_irq);
-
-/*
- * success: return IRQ number (>0)
- * failure: return =< 0
- */
-int acpi_register_gsi(struct device *dev, u32 gsi, int trigger, int polarity)
-{
-	unsigned int irq;
-	unsigned int irq_type;
-
-	/*
-	 * ACPI have no bindings to indicate SPI or PPI, so we
-	 * use different mappings from DT in ACPI.
-	 *
-	 * For FDT
-	 * PPI interrupt: in the range [0, 15];
-	 * SPI interrupt: in the range [0, 987];
-	 *
-	 * For ACPI, GSI should be unique so using
-	 * the hwirq directly for the mapping:
-	 * PPI interrupt: in the range [16, 31];
-	 * SPI interrupt: in the range [32, 1019];
-	 */
-
-	if (trigger == ACPI_EDGE_SENSITIVE &&
-				polarity == ACPI_ACTIVE_LOW)
-		irq_type = IRQ_TYPE_EDGE_FALLING;
-	else if (trigger == ACPI_EDGE_SENSITIVE &&
-				polarity == ACPI_ACTIVE_HIGH)
-		irq_type = IRQ_TYPE_EDGE_RISING;
-	else if (trigger == ACPI_LEVEL_SENSITIVE &&
-				polarity == ACPI_ACTIVE_LOW)
-		irq_type = IRQ_TYPE_LEVEL_LOW;
-	else if (trigger == ACPI_LEVEL_SENSITIVE &&
-				polarity == ACPI_ACTIVE_HIGH)
-		irq_type = IRQ_TYPE_LEVEL_HIGH;
-	else
-		irq_type = IRQ_TYPE_NONE;
-
-	/*
-	 * Since only one GIC is supported in ACPI 5.0, we can
-	 * create mapping refer to the default domain
-	 */
-	irq = irq_create_mapping(NULL, gsi);
-	if (!irq)
-		return irq;
-
-	/* Set irq type if specified and different than the current one */
-	if (irq_type != IRQ_TYPE_NONE &&
-		irq_type != irq_get_trigger_type(irq))
-		irq_set_irq_type(irq, irq_type);
-	return irq;
-}
-EXPORT_SYMBOL_GPL(acpi_register_gsi);
-
-void acpi_unregister_gsi(u32 gsi)
-{
-}
-EXPORT_SYMBOL_GPL(acpi_unregister_gsi);
-
 static int __init acpi_parse_fadt(struct acpi_table_header *table)
 {
 	struct acpi_table_fadt *fadt = (struct acpi_table_fadt *)table;