[PATCH V8 1/3] ACPI: Add support for ResourceSource/IRQ domain mapping

[Agustin Vega-Frias]

When an Extended IRQ Resource contains a valid ResourceSource
use it to map the IRQ on the domain associated with the ACPI
device referenced.

With this in place an irqchip driver can create its domain using
irq_domain_create_linear and pass the device fwnode to create
the domain mapping. When dependent devices are probed these
changes allow the ACPI core find the domain and map the IRQ.

Signed-off-by: Agustin Vega-Frias <agustinv@xxxxxxxxxxxxxx>
---
 drivers/acpi/Makefile         |  2 +-
 drivers/acpi/{gsi.c => irq.c} | 99 +++++++++++++++++++++++++++++++++++++------
 drivers/acpi/resource.c       | 29 +++++++------
 include/linux/acpi.h          | 19 +++++++++
 4 files changed, 122 insertions(+), 27 deletions(-)
 rename drivers/acpi/{gsi.c => irq.c} (52%)

diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 9ed0878..a391bbc 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -55,7 +55,7 @@ acpi-$(CONFIG_DEBUG_FS)		+= debugfs.o
 acpi-$(CONFIG_ACPI_NUMA)	+= numa.o
 acpi-$(CONFIG_ACPI_PROCFS_POWER) += cm_sbs.o
 acpi-y				+= acpi_lpat.o
-acpi-$(CONFIG_ACPI_GENERIC_GSI) += gsi.o
+acpi-$(CONFIG_ACPI_GENERIC_GSI) += irq.o
 acpi-$(CONFIG_ACPI_WATCHDOG)	+= acpi_watchdog.o
 
 # These are (potentially) separate modules
diff --git a/drivers/acpi/gsi.c b/drivers/acpi/irq.c
similarity index 52%
rename from drivers/acpi/gsi.c
rename to drivers/acpi/irq.c
index ee9e0f2..e82eb6e 100644
--- a/drivers/acpi/gsi.c
+++ b/drivers/acpi/irq.c
@@ -18,6 +18,45 @@
 static struct fwnode_handle *acpi_gsi_domain_id;
 
 /**
+ * acpi_get_irq_source_fwhandle() - Retrieve the fwhandle of the given
+ *                                  acpi_resource_source which is used
+ *                                  to be used as an IRQ domain id
+ * @source: acpi_resource_source to use for the lookup
+ *
+ * Returns: The appropriate IRQ fwhandle domain id
+ *          NULL on failure
+ */
+struct fwnode_handle *
+acpi_get_irq_source_fwhandle(const struct acpi_resource_source *source)
+{
+	struct fwnode_handle *result;
+	struct acpi_device *device;
+	acpi_handle handle;
+	acpi_status status;
+
+	if (!source->string_length)
+		return acpi_gsi_domain_id;
+
+	status = acpi_get_handle(NULL, source->string_ptr, &handle);
+	if (ACPI_FAILURE(status)) {
+		pr_warn("Could not find handle for %s\n", source->string_ptr);
+		return NULL;
+	}
+
+	device = acpi_bus_get_acpi_device(handle);
+	if (!device) {
+		pr_warn("Could not get device for %s\n", source->string_ptr);
+		return NULL;
+	}
+
+	result = &device->fwnode;
+	acpi_bus_put_acpi_device(device);
+
+	return result;
+}
+EXPORT_SYMBOL_GPL(acpi_get_irq_source_fwhandle);
+
+/**
  * acpi_gsi_to_irq() - Retrieve the linux irq number for a given GSI
  * @gsi: GSI IRQ number to map
  * @irq: pointer where linux IRQ number is stored
@@ -42,6 +81,51 @@ int acpi_gsi_to_irq(u32 gsi, unsigned int *irq)
 EXPORT_SYMBOL_GPL(acpi_gsi_to_irq);
 
 /**
+ * acpi_register_irq() - Map a hardware to a linux IRQ number
+ * @source: IRQ source
+ * @hwirq: Hardware IRQ number
+ * @trigger: trigger type of the IRQ number to be mapped
+ * @polarity: polarity of the IRQ to be mapped
+ *
+ * Returns: a valid linux IRQ number on success
+ *          -EINVAL on failure
+ *          -EPROBE_DEFER if the IRQ domain lookup failed
+ */
+int acpi_register_irq(struct fwnode_handle *source, u32 hwirq, int trigger,
+		      int polarity)
+{
+	struct irq_fwspec fwspec;
+
+	if (!source)
+		source = acpi_gsi_domain_id;
+
+	if (irq_find_matching_fwnode(source, DOMAIN_BUS_ANY) == NULL)
+		return -EPROBE_DEFER;
+
+	fwspec.fwnode = source;
+	fwspec.param[0] = hwirq;
+	fwspec.param[1] = acpi_dev_get_irq_type(trigger, polarity);
+	fwspec.param_count = 2;
+
+	return irq_create_fwspec_mapping(&fwspec);
+}
+EXPORT_SYMBOL_GPL(acpi_register_irq);
+
+/**
+ * acpi_unregister_irq() - Free a Hardware IRQ<->linux IRQ number mapping
+ * @hwirq: Hardware IRQ number
+ */
+void acpi_unregister_irq(struct fwnode_handle *source, u32 hwirq)
+{
+	struct irq_domain *d = irq_find_matching_fwnode(source,
+							DOMAIN_BUS_ANY);
+	int irq = irq_find_mapping(d, hwirq);
+
+	irq_dispose_mapping(irq);
+}
+EXPORT_SYMBOL_GPL(acpi_unregister_irq);
+
+/**
  * acpi_register_gsi() - Map a GSI to a linux IRQ number
  * @dev: device for which IRQ has to be mapped
  * @gsi: GSI IRQ number
@@ -54,19 +138,12 @@ int acpi_gsi_to_irq(u32 gsi, unsigned int *irq)
 int acpi_register_gsi(struct device *dev, u32 gsi, int trigger,
 		      int polarity)
 {
-	struct irq_fwspec fwspec;
-
 	if (WARN_ON(!acpi_gsi_domain_id)) {
 		pr_warn("GSI: No registered irqchip, giving up\n");
 		return -EINVAL;
 	}
 
-	fwspec.fwnode = acpi_gsi_domain_id;
-	fwspec.param[0] = gsi;
-	fwspec.param[1] = acpi_dev_get_irq_type(trigger, polarity);
-	fwspec.param_count = 2;
-
-	return irq_create_fwspec_mapping(&fwspec);
+	return acpi_register_irq(acpi_gsi_domain_id, gsi, trigger, polarity);
 }
 EXPORT_SYMBOL_GPL(acpi_register_gsi);
 
@@ -76,11 +153,7 @@ int acpi_register_gsi(struct device *dev, u32 gsi, int trigger,
  */
 void acpi_unregister_gsi(u32 gsi)
 {
-	struct irq_domain *d = irq_find_matching_fwnode(acpi_gsi_domain_id,
-							DOMAIN_BUS_ANY);
-	int irq = irq_find_mapping(d, gsi);
-
-	irq_dispose_mapping(irq);
+	acpi_unregister_irq(acpi_gsi_domain_id, gsi);
 }
 EXPORT_SYMBOL_GPL(acpi_unregister_gsi);
 
diff --git a/drivers/acpi/resource.c b/drivers/acpi/resource.c
index 56241eb..98b94eb 100644
--- a/drivers/acpi/resource.c
+++ b/drivers/acpi/resource.c
@@ -374,21 +374,22 @@ unsigned int acpi_dev_get_irq_type(int triggering, int polarity)
 }
 EXPORT_SYMBOL_GPL(acpi_dev_get_irq_type);
 
-static void acpi_dev_irqresource_disabled(struct resource *res, u32 gsi)
+static void acpi_dev_irqresource_disabled(struct resource *res, u32 hwirq)
 {
-	res->start = gsi;
-	res->end = gsi;
+	res->start = hwirq;
+	res->end = hwirq;
 	res->flags = IORESOURCE_IRQ | IORESOURCE_DISABLED | IORESOURCE_UNSET;
 }
 
-static void acpi_dev_get_irqresource(struct resource *res, u32 gsi,
+static void acpi_dev_get_irqresource(struct resource *res, u32 hwirq,
+				     struct fwnode_handle *source,
 				     u8 triggering, u8 polarity, u8 shareable,
 				     bool legacy)
 {
 	int irq, p, t;
 
-	if (!valid_IRQ(gsi)) {
-		acpi_dev_irqresource_disabled(res, gsi);
+	if (!source && !valid_IRQ(hwirq)) {
+		acpi_dev_irqresource_disabled(res, hwirq);
 		return;
 	}
 
@@ -402,25 +403,25 @@ static void acpi_dev_get_irqresource(struct resource *res, u32 gsi,
 	 * using extended IRQ descriptors we take the IRQ configuration
 	 * from _CRS directly.
 	 */
-	if (legacy && !acpi_get_override_irq(gsi, &t, &p)) {
+	if (legacy && !acpi_get_override_irq(hwirq, &t, &p)) {
 		u8 trig = t ? ACPI_LEVEL_SENSITIVE : ACPI_EDGE_SENSITIVE;
 		u8 pol = p ? ACPI_ACTIVE_LOW : ACPI_ACTIVE_HIGH;
 
 		if (triggering != trig || polarity != pol) {
-			pr_warning("ACPI: IRQ %d override to %s, %s\n", gsi,
-				   t ? "level" : "edge", p ? "low" : "high");
+			pr_warn("ACPI: IRQ %d override to %s, %s\n", hwirq,
+				t ? "level" : "edge", p ? "low" : "high");
 			triggering = trig;
 			polarity = pol;
 		}
 	}
 
 	res->flags = acpi_dev_irq_flags(triggering, polarity, shareable);
-	irq = acpi_register_gsi(NULL, gsi, triggering, polarity);
+	irq = acpi_register_irq(source, hwirq, triggering, polarity);
 	if (irq >= 0) {
 		res->start = irq;
 		res->end = irq;
 	} else {
-		acpi_dev_irqresource_disabled(res, gsi);
+		acpi_dev_irqresource_disabled(res, hwirq);
 	}
 }
 
@@ -448,6 +449,7 @@ bool acpi_dev_resource_interrupt(struct acpi_resource *ares, int index,
 {
 	struct acpi_resource_irq *irq;
 	struct acpi_resource_extended_irq *ext_irq;
+	struct fwnode_handle *src;
 
 	switch (ares->type) {
 	case ACPI_RESOURCE_TYPE_IRQ:
@@ -460,7 +462,7 @@ bool acpi_dev_resource_interrupt(struct acpi_resource *ares, int index,
 			acpi_dev_irqresource_disabled(res, 0);
 			return false;
 		}
-		acpi_dev_get_irqresource(res, irq->interrupts[index],
+		acpi_dev_get_irqresource(res, irq->interrupts[index], NULL,
 					 irq->triggering, irq->polarity,
 					 irq->sharable, true);
 		break;
@@ -470,7 +472,8 @@ bool acpi_dev_resource_interrupt(struct acpi_resource *ares, int index,
 			acpi_dev_irqresource_disabled(res, 0);
 			return false;
 		}
-		acpi_dev_get_irqresource(res, ext_irq->interrupts[index],
+		src = acpi_get_irq_source_fwhandle(&ext_irq->resource_source);
+		acpi_dev_get_irqresource(res, ext_irq->interrupts[index], src,
 					 ext_irq->triggering, ext_irq->polarity,
 					 ext_irq->sharable, false);
 		break;
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 61a3d90..154e576 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -321,6 +321,25 @@ void acpi_set_irq_model(enum acpi_irq_model_id model,
  */
 void acpi_unregister_gsi (u32 gsi);
 
+#ifdef CONFIG_ACPI_GENERIC_GSI
+struct fwnode_handle *
+acpi_get_irq_source_fwhandle(const struct acpi_resource_source *source);
+int acpi_register_irq(struct fwnode_handle *source, u32 hwirq, int trigger,
+		      int polarity);
+void acpi_unregister_irq(struct fwnode_handle *source, u32 hwirq);
+#else
+#define acpi_get_irq_source_fwhandle(source) (NULL)
+static inline int acpi_register_irq(struct fwnode_handle *source, u32 hwirq,
+				    int trigger, int polarity)
+{
+	return acpi_register_gsi(NULL, hwirq, trigger, polarity);
+}
+static inline void acpi_unregister_irq(struct fwnode_handle *source, u32 hwirq)
+{
+	acpi_unregister_gsi(hwirq);
+}
+#endif
+
 struct pci_dev;
 
 int acpi_pci_irq_enable (struct pci_dev *dev);
-- 
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