[PATCH] PCI: add pci_find_next_capability()
Some devices have more than one capability of the same type. For
example, the PCI header for the PathScale InfiniPath looks like:
04:01.0 InfiniBand: Unknown device 1fc1:000d (rev 02)
Subsystem: Unknown device 1fc1:000d
Flags: bus master, fast devsel, latency 0, IRQ 193
Memory at fea00000 (64-bit, non-prefetchable) [size=2M]
Capabilities: [c0] HyperTransport: Slave or Primary Interface
Capabilities: [f8] HyperTransport: Interrupt Discovery and Configuration
There are _two_ HyperTransport capabilities, and the PathScale driver
wants to look at both of them.
The current pci_find_capability() API doesn't work for this, since it
only allows us to get to the first capability of a given type. The
patch below introduces a new pci_find_next_capability(), which can be
used in a loop like
for (pos = pci_find_capability(pdev, <ID>);
pos;
pos = pci_find_next_capability(pdev, pos, <ID>)) {
/* ... */
}
Signed-off-by: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Matthew Wilcox <matthew@wil.cx>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index e74d758..8e287a8 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -63,11 +63,38 @@
return max;
}
+static int __pci_find_next_cap(struct pci_bus *bus, unsigned int devfn, u8 pos, int cap)
+{
+ u8 id;
+ int ttl = 48;
+
+ while (ttl--) {
+ pci_bus_read_config_byte(bus, devfn, pos, &pos);
+ if (pos < 0x40)
+ break;
+ pos &= ~3;
+ pci_bus_read_config_byte(bus, devfn, pos + PCI_CAP_LIST_ID,
+ &id);
+ if (id == 0xff)
+ break;
+ if (id == cap)
+ return pos;
+ pos += PCI_CAP_LIST_NEXT;
+ }
+ return 0;
+}
+
+int pci_find_next_capability(struct pci_dev *dev, u8 pos, int cap)
+{
+ return __pci_find_next_cap(dev->bus, dev->devfn,
+ pos + PCI_CAP_LIST_NEXT, cap);
+}
+EXPORT_SYMBOL_GPL(pci_find_next_capability);
+
static int __pci_bus_find_cap(struct pci_bus *bus, unsigned int devfn, u8 hdr_type, int cap)
{
u16 status;
- u8 pos, id;
- int ttl = 48;
+ u8 pos;
pci_bus_read_config_word(bus, devfn, PCI_STATUS, &status);
if (!(status & PCI_STATUS_CAP_LIST))
@@ -76,24 +103,15 @@
switch (hdr_type) {
case PCI_HEADER_TYPE_NORMAL:
case PCI_HEADER_TYPE_BRIDGE:
- pci_bus_read_config_byte(bus, devfn, PCI_CAPABILITY_LIST, &pos);
+ pos = PCI_CAPABILITY_LIST;
break;
case PCI_HEADER_TYPE_CARDBUS:
- pci_bus_read_config_byte(bus, devfn, PCI_CB_CAPABILITY_LIST, &pos);
+ pos = PCI_CB_CAPABILITY_LIST;
break;
default:
return 0;
}
- while (ttl-- && pos >= 0x40) {
- pos &= ~3;
- pci_bus_read_config_byte(bus, devfn, pos + PCI_CAP_LIST_ID, &id);
- if (id == 0xff)
- break;
- if (id == cap)
- return pos;
- pci_bus_read_config_byte(bus, devfn, pos + PCI_CAP_LIST_NEXT, &pos);
- }
- return 0;
+ return __pci_find_next_cap(bus, devfn, pos, cap);
}
/**