[RFC PATCH v3 06/17] pnp.h: Reconfigure IRQ in pnp_irq() to support deferred probe

[Sunil V L]

PNP devices add the IRQ resources to PNP data structure early during
boot from ACPI resource structure. As part of this, the Interrupt
resource (GSI) are registered and appropriate linux IRQ is saved
directly in PNP data structure while creating PNP devices. But at this
time, the interrupt controller for the GSI (either via GSI vector
mapping or via ResourceSource in Interrupt()) may not be probed and
initialized. Hence, the IRQ number in PNP data structure may not be the
linux IRQ number. When the actual driver for the PNP device get probed,
it will get incorrect linux IRQ number.

Fix this issue similar to how platform devices handle this. Basically,
while creating PNP devices, the hwirq number is saved in PNP device and
marked as disabled since acpi_register_gsi() would have failed. When the
actual driver calls pnp_irq(), get the linux IRQ number again if the IRQ
is disabled.

Signed-off-by: Sunil V L <sunilvl at ventanamicro.com>
---
 drivers/pnp/pnpacpi/core.c |  7 +++++++
 include/linux/pnp.h        | 14 ++++++++++++--
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/drivers/pnp/pnpacpi/core.c b/drivers/pnp/pnpacpi/core.c
index 6ab272c84b7b..239355977d4c 100644
--- a/drivers/pnp/pnpacpi/core.c
+++ b/drivers/pnp/pnpacpi/core.c
@@ -326,3 +326,10 @@ static int __init pnpacpi_setup(char *str)
 }
 
 __setup("pnpacpi=", pnpacpi_setup);
+
+void pnpacpi_reconfigure_irq(struct pnp_dev *dev, unsigned int index, struct resource *res)
+{
+	if (has_acpi_companion(&dev->dev))
+		acpi_irq_get(ACPI_HANDLE(&dev->dev), index, res);
+}
+EXPORT_SYMBOL(pnpacpi_reconfigure_irq);
diff --git a/include/linux/pnp.h b/include/linux/pnp.h
index c2a7cfbca713..8753eb4275b0 100644
--- a/include/linux/pnp.h
+++ b/include/linux/pnp.h
@@ -26,6 +26,7 @@ struct pnp_dev;
 #ifdef CONFIG_PNP
 struct resource *pnp_get_resource(struct pnp_dev *dev, unsigned long type,
 				unsigned int num);
+
 #else
 static inline struct resource *pnp_get_resource(struct pnp_dev *dev,
 			unsigned long type, unsigned int num)
@@ -146,13 +147,22 @@ static inline resource_size_t pnp_mem_len(struct pnp_dev *dev,
 	return 0;
 }
 
+#ifdef CONFIG_PNPACPI
+void pnpacpi_reconfigure_irq(struct pnp_dev *dev, unsigned int index, struct resource *res);
+#endif
 
-static inline resource_size_t pnp_irq(struct pnp_dev *dev, unsigned int bar)
+static inline int pnp_irq(struct pnp_dev *dev, unsigned int bar)
 {
 	struct resource *res = pnp_get_resource(dev, IORESOURCE_IRQ, bar);
 
-	if (pnp_resource_valid(res))
+	if (pnp_resource_valid(res)) {
+#ifdef CONFIG_PNPACPI
+		if (!pnp_resource_enabled(res))
+			pnpacpi_reconfigure_irq(dev, bar, res);
+#endif
 		return res->start;
+	}
+
 	return -1;
 }
 
-- 
2.39.2