[PATCH V6 1/3] ACPI: Retry IRQ conversion if it failed previously

[Agustin Vega-Frias]

This allows probe deferral to work properly when a dependent device
fails to get a valid IRQ because the IRQ domain was not registered
at the time the resources were added to the platform_device.

Signed-off-by: Agustin Vega-Frias <agustinv at codeaurora.org>
---
 drivers/acpi/resource.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++++
 drivers/base/platform.c |  9 +++++++-
 include/linux/acpi.h    |  7 ++++++
 3 files changed, 74 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/resource.c b/drivers/acpi/resource.c
index 56241eb..4beda15 100644
--- a/drivers/acpi/resource.c
+++ b/drivers/acpi/resource.c
@@ -664,3 +664,62 @@ int acpi_dev_filter_resource_type(struct acpi_resource *ares,
 	return (type & types) ? 0 : 1;
 }
 EXPORT_SYMBOL_GPL(acpi_dev_filter_resource_type);
+
+struct acpi_irq_get_ctx {
+	unsigned int index;
+	struct resource *res;
+};
+
+static acpi_status acpi_irq_get_cb(struct acpi_resource *ares, void *context)
+{
+	struct acpi_irq_get_ctx *ctx = context;
+	struct acpi_resource_irq *irq;
+	struct acpi_resource_extended_irq *ext_irq;
+
+	switch (ares->type) {
+	case ACPI_RESOURCE_TYPE_IRQ:
+		irq = &ares->data.irq;
+		if (ctx->index < irq->interrupt_count) {
+			acpi_dev_resource_interrupt(ares, ctx->index, ctx->res);
+			return AE_CTRL_TERMINATE;
+		}
+		ctx->index -= irq->interrupt_count;
+		break;
+	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
+		ext_irq = &ares->data.extended_irq;
+		if (ctx->index < ext_irq->interrupt_count) {
+			acpi_dev_resource_interrupt(ares, ctx->index, ctx->res);
+			return AE_CTRL_TERMINATE;
+		}
+		ctx->index -= ext_irq->interrupt_count;
+		break;
+	}
+
+	return AE_OK;
+}
+
+/**
+ * acpi_irq_get - Look for the ACPI IRQ resource with the given index and
+ *                use it to initialize the given Linux IRQ resource.
+ * @handle ACPI device handle
+ * @index  ACPI IRQ resource index to lookup
+ * @res    Linux IRQ resource to initialize
+ *
+ * Return: 0 on success
+ *         -EINVAL if an error occurs
+ *         -EPROBE_DEFER if the IRQ lookup/conversion failed
+ */
+int acpi_irq_get(acpi_handle handle, unsigned int index, struct resource *res)
+{
+	struct acpi_irq_get_ctx ctx = { index, res };
+	acpi_status status;
+
+	status = acpi_walk_resources(handle, METHOD_NAME__CRS,
+				     acpi_irq_get_cb, &ctx);
+	if (ACPI_FAILURE(status))
+		return -EINVAL;
+	if (res->flags & IORESOURCE_DISABLED)
+		return -EPROBE_DEFER;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(acpi_irq_get);
diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index c4af003..61423d2 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -102,6 +102,14 @@ int platform_get_irq(struct platform_device *dev, unsigned int num)
 	}
 
 	r = platform_get_resource(dev, IORESOURCE_IRQ, num);
+	if (r && r->flags & IORESOURCE_DISABLED && ACPI_COMPANION(&dev->dev)) {
+		int ret;
+
+		ret = acpi_irq_get(ACPI_HANDLE(&dev->dev), num, r);
+		if (ret)
+			return ret;
+	}
+
 	/*
 	 * The resources may pass trigger flags to the irqs that need
 	 * to be set up. It so happens that the trigger flags for
@@ -1450,4 +1458,3 @@ void __init early_platform_cleanup(void)
 		memset(&pd->dev.devres_head, 0, sizeof(pd->dev.devres_head));
 	}
 }
-
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index ddbeda6..40213c4 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -405,6 +405,7 @@ bool acpi_dev_resource_ext_address_space(struct acpi_resource *ares,
 unsigned int acpi_dev_get_irq_type(int triggering, int polarity);
 bool acpi_dev_resource_interrupt(struct acpi_resource *ares, int index,
 				 struct resource *res);
+int acpi_irq_get(acpi_handle handle, unsigned int index, struct resource *res);
 
 void acpi_dev_free_resource_list(struct list_head *list);
 int acpi_dev_get_resources(struct acpi_device *adev, struct list_head *list,
@@ -762,6 +763,12 @@ static inline int acpi_reconfig_notifier_unregister(struct notifier_block *nb)
 	return -EINVAL;
 }
 
+static inline int acpi_irq_get(acpi_handle handle, unsigned int index,
+			       struct resource *res)
+{
+	return -EINVAL;
+}
+
 #endif	/* !CONFIG_ACPI */
 
 #ifdef CONFIG_ACPI_HOTPLUG_IOAPIC
-- 
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