[PATCH] ACPI, PCI: Get PRT entry during acpi_pci_enable_irq()

From: Yinghai Lu
Date: Tue Feb 12 2013 - 14:11:55 EST

Peter Hurley found "irq 18 nobody cared" with pci-next, and dmesg has

[ 8.983246] pci 0000:00:1e.0: can't derive routing for PCI INT A
[ 8.983600] snd_ctxfi 0000:09:02.0: PCI INT A: no GSI - using ISA IRQ 5

bisect to
| commit 4f535093cf8f6da8cfda7c36c2c1ecd2e9586ee4
| PCI: Put pci_dev in device tree as early as possible

It turns out we need to call acpi_pci_irq_add_prt() after the pci bridges
are scanned.

Bjorn said:
The bus number binding means acpi_pci_irq_add_prt() has to happen
after enumerating everything below a bridge, and it will prevent us
from doing any bus number reassignment for hotplug.

I think we should remove the bus numbers from the cached _PRT (or
maybe even remove the _PRT caching completely). When we enable a PCI
device's IRQ, we should search up the PCI device tree looking for a
_PRT associated with each node, and applying normal PCI bridge
swizzling when we don't find a _PRT. I think this can be done without
using PCI bus numbers at all.

So here we try to remove _PRT caching completely.

-v2: check !handle early.

Reported-and-tested-by: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
Suggested-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>

---
drivers/acpi/pci_irq.c | 95 +++++++++++++++++---------------------------
drivers/acpi/pci_root.c | 18 --------
drivers/pci/pci-acpi.c | 24 -----------
include/acpi/acpi_drivers.h | 5 --
4 files changed, 38 insertions(+), 104 deletions(-)

Index: linux-2.6/drivers/acpi/pci_irq.c
===================================================================
--- linux-2.6.orig/drivers/acpi/pci_irq.c
+++ linux-2.6/drivers/acpi/pci_irq.c
@@ -53,9 +53,6 @@ struct acpi_prt_entry {
u32 index; /* GSI, or link _CRS index */
};

-static LIST_HEAD(acpi_prt_list);
-static DEFINE_SPINLOCK(acpi_prt_lock);
-
static inline char pin_name(int pin)
{
return 'A' + pin - 1;
@@ -65,28 +62,6 @@ static inline char pin_name(int pin)
PCI IRQ Routing Table (PRT) Support
-------------------------------------------------------------------------- */

-static struct acpi_prt_entry *acpi_pci_irq_find_prt_entry(struct pci_dev *dev,
- int pin)
-{
- struct acpi_prt_entry *entry;
- int segment = pci_domain_nr(dev->bus);
- int bus = dev->bus->number;
- int device = PCI_SLOT(dev->devfn);
-
- spin_lock(&acpi_prt_lock);
- list_for_each_entry(entry, &acpi_prt_list, list) {
- if ((segment == entry->id.segment)
- && (bus == entry->id.bus)
- && (device == entry->id.device)
- && (pin == entry->pin)) {
- spin_unlock(&acpi_prt_lock);
- return entry;
- }
- }
- spin_unlock(&acpi_prt_lock);
- return NULL;
-}
-
/* http://bugzilla.kernel.org/show_bug.cgi?id=4773 */
static const struct dmi_system_id medion_md9580[] = {
{
@@ -184,11 +159,19 @@ static void do_prt_fixups(struct acpi_pr
}
}

-static int acpi_pci_irq_add_entry(acpi_handle handle, int segment, int bus,
- struct acpi_pci_routing_table *prt)
+static int acpi_pci_irq_check_entry(acpi_handle handle, struct pci_dev *dev,
+ int pin, struct acpi_pci_routing_table *prt,
+ struct acpi_prt_entry **entry_ptr)
{
+ int segment = pci_domain_nr(dev->bus);
+ int bus = dev->bus->number;
+ int device = PCI_SLOT(dev->devfn);
struct acpi_prt_entry *entry;

+ if (((prt->address >> 16) & 0xffff) != device ||
+ prt->pin + 1 != pin)
+ return -ENODEV;
+
entry = kzalloc(sizeof(struct acpi_prt_entry), GFP_KERNEL);
if (!entry)
return -ENOMEM;
@@ -237,26 +220,33 @@ static int acpi_pci_irq_add_entry(acpi_h
entry->id.device, pin_name(entry->pin),
prt->source, entry->index));

- spin_lock(&acpi_prt_lock);
- list_add_tail(&entry->list, &acpi_prt_list);
- spin_unlock(&acpi_prt_lock);
+ *entry_ptr = entry;

return 0;
}

-int acpi_pci_irq_add_prt(acpi_handle handle, int segment, int bus)
+static int acpi_pci_irq_find_prt_entry(struct pci_dev *dev,
+ int pin, struct acpi_prt_entry **entry_ptr)
{
acpi_status status;
struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
struct acpi_pci_routing_table *entry;
+ acpi_handle handle = NULL;
+
+ if (dev->bus->bridge)
+ handle = ACPI_HANDLE(dev->bus->bridge);
+
+ if (!handle)
+ return -ENODEV;

/* 'handle' is the _PRT's parent (root bridge or PCI-PCI bridge) */
status = acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
if (ACPI_FAILURE(status))
return -ENODEV;

- printk(KERN_DEBUG "ACPI: PCI Interrupt Routing Table [%s._PRT]\n",
- (char *) buffer.pointer);
+ dev_printk(KERN_DEBUG, &dev->dev,
+ "ACPI: PCI Interrupt Routing Table [%s._PRT]\n",
+ (char *) buffer.pointer);

kfree(buffer.pointer);

@@ -273,7 +263,9 @@ int acpi_pci_irq_add_prt(acpi_handle han

entry = buffer.pointer;
while (entry && (entry->length > 0)) {
- acpi_pci_irq_add_entry(handle, segment, bus, entry);
+ if (!acpi_pci_irq_check_entry(handle, dev, pin,
+ entry, entry_ptr))
+ break;
entry = (struct acpi_pci_routing_table *)
((unsigned long)entry + entry->length);
}
@@ -282,23 +274,6 @@ int acpi_pci_irq_add_prt(acpi_handle han
return 0;
}

-void acpi_pci_irq_del_prt(int segment, int bus)
-{
- struct acpi_prt_entry *entry, *tmp;
-
- printk(KERN_DEBUG
- "ACPI: Delete PCI Interrupt Routing Table for %04x:%02x\n",
- segment, bus);
- spin_lock(&acpi_prt_lock);
- list_for_each_entry_safe(entry, tmp, &acpi_prt_list, list) {
- if (segment == entry->id.segment && bus == entry->id.bus) {
- list_del(&entry->list);
- kfree(entry);
- }
- }
- spin_unlock(&acpi_prt_lock);
-}
-
/* --------------------------------------------------------------------------
PCI Interrupt Routing Support
-------------------------------------------------------------------------- */
@@ -359,12 +334,13 @@ static int acpi_reroute_boot_interrupt(s

static struct acpi_prt_entry *acpi_pci_irq_lookup(struct pci_dev *dev, int pin)
{
- struct acpi_prt_entry *entry;
+ struct acpi_prt_entry *entry = NULL;
struct pci_dev *bridge;
u8 bridge_pin, orig_pin = pin;
+ int ret;

- entry = acpi_pci_irq_find_prt_entry(dev, pin);
- if (entry) {
+ ret = acpi_pci_irq_find_prt_entry(dev, pin, &entry);
+ if (!ret && entry) {
#ifdef CONFIG_X86_IO_APIC
acpi_reroute_boot_interrupt(dev, entry);
#endif /* CONFIG_X86_IO_APIC */
@@ -373,7 +349,7 @@ static struct acpi_prt_entry *acpi_pci_i
return entry;
}

- /*
+ /*
* Attempt to derive an IRQ for this device from a parent bridge's
* PCI interrupt routing entry (eg. yenta bridge and add-in card bridge).
*/
@@ -393,8 +369,8 @@ static struct acpi_prt_entry *acpi_pci_i
pin = bridge_pin;
}

- entry = acpi_pci_irq_find_prt_entry(bridge, pin);
- if (entry) {
+ ret = acpi_pci_irq_find_prt_entry(bridge, pin, &entry);
+ if (!ret && entry) {
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"Derived GSI for %s INT %c from %s\n",
pci_name(dev), pin_name(orig_pin),
@@ -470,6 +446,7 @@ int acpi_pci_irq_enable(struct pci_dev *
dev_warn(&dev->dev, "PCI INT %c: no GSI\n",
pin_name(pin));
}
+
return 0;
}

@@ -477,6 +454,7 @@ int acpi_pci_irq_enable(struct pci_dev *
if (rc < 0) {
dev_warn(&dev->dev, "PCI INT %c: failed to register GSI\n",
pin_name(pin));
+ kfree(entry);
return rc;
}
dev->irq = rc;
@@ -491,6 +469,7 @@ int acpi_pci_irq_enable(struct pci_dev *
(triggering == ACPI_LEVEL_SENSITIVE) ? "level" : "edge",
(polarity == ACPI_ACTIVE_LOW) ? "low" : "high", dev->irq);

+ kfree(entry);
return 0;
}

@@ -513,6 +492,8 @@ void acpi_pci_irq_disable(struct pci_dev
else
gsi = entry->index;

+ kfree(entry);
+
/*
* TBD: It might be worth clearing dev->irq by magic constant
* (e.g. PCI_UNDEFINED_IRQ).
Index: linux-2.6/drivers/acpi/pci_root.c
===================================================================
--- linux-2.6.orig/drivers/acpi/pci_root.c
+++ linux-2.6/drivers/acpi/pci_root.c
@@ -413,7 +413,6 @@ static int acpi_pci_root_add(struct acpi
acpi_status status;
int result;
struct acpi_pci_root *root;
- acpi_handle handle;
struct acpi_pci_driver *driver;
u32 flags, base_flags;
bool is_osc_granted = false;
@@ -468,16 +467,6 @@ static int acpi_pci_root_add(struct acpi
acpi_device_name(device), acpi_device_bid(device),
root->segment, &root->secondary);

- /*
- * PCI Routing Table
- * -----------------
- * Evaluate and parse _PRT, if exists.
- */
- status = acpi_get_handle(device->handle, METHOD_NAME__PRT, &handle);
- if (ACPI_SUCCESS(status))
- result = acpi_pci_irq_add_prt(device->handle, root->segment,
- root->secondary.start);
-
root->mcfg_addr = acpi_pci_root_get_mcfg_addr(device->handle);

/*
@@ -602,7 +591,6 @@ out_del_root:
list_del(&root->node);
mutex_unlock(&acpi_pci_root_lock);

- acpi_pci_irq_del_prt(root->segment, root->secondary.start);
end:
kfree(root);
return result;
@@ -610,8 +598,6 @@ end:

static void acpi_pci_root_remove(struct acpi_device *device)
{
- acpi_status status;
- acpi_handle handle;
struct acpi_pci_root *root = acpi_driver_data(device);
struct acpi_pci_driver *driver;

@@ -626,10 +612,6 @@ static void acpi_pci_root_remove(struct
device_set_run_wake(root->bus->bridge, false);
pci_acpi_remove_bus_pm_notifier(device);

- status = acpi_get_handle(device->handle, METHOD_NAME__PRT, &handle);
- if (ACPI_SUCCESS(status))
- acpi_pci_irq_del_prt(root->segment, root->secondary.start);
-
pci_remove_root_bus(root->bus);

mutex_lock(&acpi_pci_root_lock);
Index: linux-2.6/drivers/pci/pci-acpi.c
===================================================================
--- linux-2.6.orig/drivers/pci/pci-acpi.c
+++ linux-2.6/drivers/pci/pci-acpi.c
@@ -307,25 +307,6 @@ static void pci_acpi_setup(struct device
struct pci_dev *pci_dev = to_pci_dev(dev);
acpi_handle handle = ACPI_HANDLE(dev);
struct acpi_device *adev;
- acpi_status status;
- acpi_handle dummy;
-
- /*
- * Evaluate and parse _PRT, if exists. This code allows parsing of
- * _PRT objects within the scope of non-bridge devices. Note that
- * _PRTs within the scope of a PCI bridge assume the bridge's
- * subordinate bus number.
- *
- * TBD: Can _PRTs exist within the scope of non-bridge PCI devices?
- */
- status = acpi_get_handle(handle, METHOD_NAME__PRT, &dummy);
- if (ACPI_SUCCESS(status)) {
- unsigned char bus;
-
- bus = pci_dev->subordinate ?
- pci_dev->subordinate->number : pci_dev->bus->number;
- acpi_pci_irq_add_prt(handle, pci_domain_nr(pci_dev->bus), bus);
- }

if (acpi_bus_get_device(handle, &adev) || !adev->wakeup.flags.valid)
return;
@@ -340,7 +321,6 @@ static void pci_acpi_setup(struct device

static void pci_acpi_cleanup(struct device *dev)
{
- struct pci_dev *pci_dev = to_pci_dev(dev);
acpi_handle handle = ACPI_HANDLE(dev);
struct acpi_device *adev;

@@ -349,10 +329,6 @@ static void pci_acpi_cleanup(struct devi
device_set_run_wake(dev, false);
pci_acpi_remove_pm_notifier(adev);
}
-
- if (pci_dev->subordinate)
- acpi_pci_irq_del_prt(pci_domain_nr(pci_dev->bus),
- pci_dev->subordinate->number);
}

static struct acpi_bus_type acpi_pci_bus = {
Index: linux-2.6/include/acpi/acpi_drivers.h
===================================================================
--- linux-2.6.orig/include/acpi/acpi_drivers.h
+++ linux-2.6/include/acpi/acpi_drivers.h
@@ -90,11 +90,6 @@ int acpi_pci_link_allocate_irq(acpi_hand
int *polarity, char **name);
int acpi_pci_link_free_irq(acpi_handle handle);

-/* ACPI PCI Interrupt Routing (pci_irq.c) */
-
-int acpi_pci_irq_add_prt(acpi_handle handle, int segment, int bus);
-void acpi_pci_irq_del_prt(int segment, int bus);
-
/* ACPI PCI Device Binding (pci_bind.c) */

struct pci_bus;
--
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