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

Kristen Accardi
2005-10-18T23:57:57Z

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>
---
I fixed this patch so that it compiles without warnings now.

diff -uprN -X linux-2.6.14-rc3/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 2005-10-18 16:26:44.000000000 -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 = (char *)entry;
+
+ return_VALUE(irq);
+}
+
+
+
/*
* acpi_pci_irq_lookup
* success: return IRQ >= 0
@@ -491,6 +513,86 @@ 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,
+ (char **)&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 +608,14 @@ 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/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 2005-10-18 16:17:30.000000000 -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
diff -uprN -X linux-2.6.14-rc3/Documentation/dontdiff linux-2.6.14-rc3.orig/include/acpi/acpi_drivers.h linux-2.6.14-rc3/include/acpi/acpi_drivers.h
--- linux-2.6.14-rc3.orig/include/acpi/acpi_drivers.h 2005-10-07 13:37:52.000000000 -0700
+++ linux-2.6.14-rc3/include/acpi/acpi_drivers.h 2005-10-18 16:20:08.000000000 -0700
@@ -55,6 +55,7 @@ int acpi_irq_penalty_init(void);
int acpi_pci_link_allocate_irq(acpi_handle handle, int index, int *edge_level,
int *active_high_low, char **name);
int acpi_pci_link_free_irq(acpi_handle handle);
+int acpi_pci_link_find_irq(acpi_handle handle);

/* ACPI PCI Interrupt Routing (pci_irq.c) */