RE: [patch 2/2] acpi: add ability to derive irq when doing a surpriseremoval of an adapter

[Kristen Accardi <kristen.c.accardi@intel.com>]

For surprise hotplug removal, the interrupt pin must be guessed, as any
attempts to read it would obviously be invalid.  This patch adds a new
function to cycle through all possible pin values, and tries to either
lookup or derive the right irq to disable.  It also adds a new function
to acpi which can be used to just find the irq, without freeing it, just
in case we guess the wrong pin.

Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>

diff -uprN -X linux-2.6.14-rc3.orig/Documentation/dontdiff linux-2.6.14-rc3.orig/drivers/acpi/pci_irq.c linux-2.6.14-rc3/drivers/acpi/pci_irq.c
--- linux-2.6.14-rc3.orig/drivers/acpi/pci_irq.c	2005-10-07 13:37:50.000000000 -0700
+++ linux-2.6.14-rc3/drivers/acpi/pci_irq.c	2005-10-11 10:02:42.000000000 -0700
@@ -298,6 +298,28 @@ acpi_pci_free_irq(struct acpi_prt_entry 
 	return_VALUE(irq);
 }
 
+
+
+static int 
+acpi_pci_find_irq(struct acpi_prt_entry *entry,
+		  int *edge_level, int *active_high_low, char **link)
+{
+	int irq;
+
+	ACPI_FUNCTION_TRACE("acpi_pci_find_irq");
+	if (entry->link.handle) {
+		irq = acpi_pci_link_find_irq(entry->link.handle);
+	} else {
+		irq = entry->link.index;
+	}
+
+	*link = entry;
+
+	return_VALUE(irq);
+}
+
+
+	
 /*
  * acpi_pci_irq_lookup
  * success: return IRQ >= 0
@@ -491,6 +513,83 @@ void __attribute__ ((weak)) acpi_unregis
 {
 }
 
+
+
+/*
+ * This function will be called only in the case of
+ * a "surprise" hot plug removal.  For surprise removals,
+ * the card has either already be yanked out of the slot, or
+ * the slot's been powered off, so we have to brute force 
+ * our way through all the possible interrupt pins to derive
+ * the GSI, then we double check with the value stored in the
+ * pci_dev structure to make sure we have the GSI that belongs
+ * to this IRQ.
+ */
+void acpi_pci_irq_disable_nodev(struct pci_dev *dev)
+{
+	int gsi = 0;
+	u8  pin = 0;
+	int edge_level = ACPI_LEVEL_SENSITIVE;
+	int active_high_low = ACPI_ACTIVE_LOW;
+	int irq;
+	struct acpi_prt_entry *entry;
+
+	ACPI_FUNCTION_TRACE("acpi_pci_irq_disable_nodev");
+
+	/* 
+	 * since our device is not present, we 
+	 * can't just read the interrupt pin
+	 * and use the value to derive the irq.
+	 * in this case, we are going to check
+	 * each returned irq value to make
+	 * sure it matches our already assigned
+	 * irq before we use it.
+	 */
+	for (pin = 0; pin < 4; pin++) {
+		/*
+	 	 * First we check the PCI IRQ routing table (PRT) for an IRQ.
+	 	 */
+		gsi = acpi_pci_irq_lookup(dev->bus, PCI_SLOT(dev->devfn), pin,
+				  &edge_level, &active_high_low, (char **)&entry,
+				  acpi_pci_find_irq);
+
+		/*
+	 	 * If no PRT entry was found, we'll try to derive an IRQ from the
+	 	 * device's parent bridge.
+	 	 */
+		if (gsi < 0)
+ 			gsi = acpi_pci_irq_derive(dev, pin,
+				&edge_level, &active_high_low, &entry, acpi_pci_find_irq);
+
+		/* 
+		 * If we could not derive the IRQ, give up on this pin number
+		 * and try a different one.
+		 */
+		if (gsi < 0)
+		 	continue;	
+		
+		if (acpi_gsi_to_irq(gsi, &irq) < 0)
+			continue;
+
+		/* 
+		 * make sure we got the right irq 
+		 */
+		if (irq == dev->irq) {
+			acpi_pci_free_irq(entry, &edge_level, &active_high_low, NULL);
+			printk(KERN_INFO PREFIX 
+				"PCI interrupt for device %s disabled\n",
+	       			pci_name(dev));
+
+			acpi_unregister_gsi(gsi);
+			return_VOID;
+		}
+	}
+	return_VOID;
+}
+
+
+
+
 void acpi_pci_irq_disable(struct pci_dev *dev)
 {
 	int gsi = 0;
@@ -506,6 +605,14 @@ void acpi_pci_irq_disable(struct pci_dev
 	pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin);
 	if (!pin)
 		return_VOID;
+
+	/* 
+	 * Check to see if the device was present 
+	 */
+	if (pin == 0xff) {
+		acpi_pci_irq_disable_nodev(dev);
+		return_VOID;
+	}
 	pin--;
 
 	/*
diff -uprN -X linux-2.6.14-rc3.orig/Documentation/dontdiff linux-2.6.14-rc3.orig/drivers/acpi/pci_link.c linux-2.6.14-rc3/drivers/acpi/pci_link.c
--- linux-2.6.14-rc3.orig/drivers/acpi/pci_link.c	2005-10-07 13:37:50.000000000 -0700
+++ linux-2.6.14-rc3/drivers/acpi/pci_link.c	2005-10-11 09:51:27.000000000 -0700
@@ -665,6 +665,41 @@ acpi_pci_link_allocate_irq(acpi_handle h
 	return_VALUE(link->irq.active);
 }
 
+
+
+int acpi_pci_link_find_irq(acpi_handle handle)
+{
+	struct acpi_device *device = NULL;
+	struct acpi_pci_link *link = NULL;
+	acpi_status result;
+
+	ACPI_FUNCTION_TRACE("acpi_pci_link_find_irq");
+
+	result = acpi_bus_get_device(handle, &device);
+	if (result) {
+		ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid link device\n"));
+		return_VALUE(-1);
+	}
+
+	link = (struct acpi_pci_link *)acpi_driver_data(device);
+	if (!link) {
+		ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid link context\n"));
+		return_VALUE(-1);
+	}
+
+	down(&acpi_link_lock);
+	if (!link->irq.initialized) {
+		up(&acpi_link_lock);
+		ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Link isn't initialized\n"));
+		return_VALUE(-1);
+	}
+
+	up(&acpi_link_lock);
+	return_VALUE(link->irq.active);
+}
+
+
+
 /*
  * We don't change link's irq information here.  After it is reenabled, we
  * continue use the info