ARM64 / ACPI: Introduce ACPI_IRQ_MODEL_GIC and register device's gsi

Introduce ACPI_IRQ_MODEL_GIC which is needed for ARM64 as GIC is
used, and then register device's gsi with the core IRQ subsystem.

acpi_register_gsi() is similar to DT based irq_of_parse_and_map(),
since gsi is unique in the system, so use hwirq number directly
for the mapping.

We are going to implement stacked domains when GICv2m, GICv3, ITS
support are added.

CC: Marc Zyngier <marc.zyngier@arm.com>
Originally-by: Amit Daniel Kachhap <amit.daniel@samsung.com>
Tested-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
Tested-by: Yijing Wang <wangyijing@huawei.com>
Tested-by: Mark Langsdorf <mlangsdo@redhat.com>
Tested-by: Jon Masters <jcm@redhat.com>
Tested-by: Timur Tabi <timur@codeaurora.org>
Tested-by: Robert Richter <rrichter@cavium.com>
Acked-by: Robert Richter <rrichter@cavium.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Grant Likely <grant.likely@linaro.org>
Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

3 files changed, 77 insertions, 0 deletions

diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
index c9203c0a1179..dec6f8aed3dc 100644
--- a/arch/arm64/kernel/acpi.c
+++ b/arch/arm64/kernel/acpi.c
@@ -76,6 +76,12 @@ 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.
  */
@@ -218,6 +224,73 @@ 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;
diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index 8b67bd0f6bb5..c412fdb28d34 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -448,6 +448,9 @@ static int __init acpi_bus_init_irq(void)
         case ACPI_IRQ_MODEL_IOSAPIC:
                 message = "IOSAPIC";
                 break;
+        case ACPI_IRQ_MODEL_GIC:
+                message = "GIC";
+                break;
         case ACPI_IRQ_MODEL_PLATFORM:
                 message = "platform specific model";
                 break;
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 6ec33c595aea..de4e86f89c83 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -73,6 +73,7 @@ enum acpi_irq_model_id {
         ACPI_IRQ_MODEL_IOAPIC,
         ACPI_IRQ_MODEL_IOSAPIC,
         ACPI_IRQ_MODEL_PLATFORM,
+        ACPI_IRQ_MODEL_GIC,
         ACPI_IRQ_MODEL_COUNT
 };