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authorMichael Ellerman <michael@ellerman.id.au>2006-11-22 18:26:18 +1100
committerGreg Kroah-Hartman <gregkh@suse.de>2006-12-20 10:54:42 -0800
commit687d5fe3dc33794efb500f42164a0588e2647914 (patch)
tree9d344d790ae2e9d6214c2b2941360e5c0ef97f7b /drivers
parentd3bac118fb27a365d5e9f54f4a078eb9b42f968f (diff)
PCI: Add pci_find_ht_capability() for finding Hypertransport capabilities
There are already several places in the kernel that want to search a PCI device for a given Hypertransport capability. Although this is possible using pci_find_capability() etc., it makes sense to encapsulate that logic in a helper - pci_find_ht_capability(). To cater for searching exhaustively for a capability, we also provide pci_find_next_ht_capability(). We also need to cater for the fact that the HT capability fields may be either 3 or 5 bits wide. pci_find_ht_capability() deals with this for you, but callers using the #defines directly must handle that themselves. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/pci/pci.c84
1 files changed, 81 insertions, 3 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 4627a51d1d6..6bfb942428e 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -68,12 +68,14 @@ pci_max_busnr(void)
#endif /* 0 */
-static int __pci_find_next_cap(struct pci_bus *bus, unsigned int devfn, u8 pos, int cap)
+#define PCI_FIND_CAP_TTL 48
+
+static int __pci_find_next_cap_ttl(struct pci_bus *bus, unsigned int devfn,
+ u8 pos, int cap, int *ttl)
{
u8 id;
- int ttl = 48;
- while (ttl--) {
+ while ((*ttl)--) {
pci_bus_read_config_byte(bus, devfn, pos, &pos);
if (pos < 0x40)
break;
@@ -89,6 +91,14 @@ static int __pci_find_next_cap(struct pci_bus *bus, unsigned int devfn, u8 pos,
return 0;
}
+static int __pci_find_next_cap(struct pci_bus *bus, unsigned int devfn,
+ u8 pos, int cap)
+{
+ int ttl = PCI_FIND_CAP_TTL;
+
+ return __pci_find_next_cap_ttl(bus, devfn, pos, cap, &ttl);
+}
+
int pci_find_next_capability(struct pci_dev *dev, u8 pos, int cap)
{
return __pci_find_next_cap(dev->bus, dev->devfn,
@@ -224,6 +234,74 @@ int pci_find_ext_capability(struct pci_dev *dev, int cap)
}
EXPORT_SYMBOL_GPL(pci_find_ext_capability);
+static int __pci_find_next_ht_cap(struct pci_dev *dev, int pos, int ht_cap)
+{
+ int rc, ttl = PCI_FIND_CAP_TTL;
+ u8 cap, mask;
+
+ if (ht_cap == HT_CAPTYPE_SLAVE || ht_cap == HT_CAPTYPE_HOST)
+ mask = HT_3BIT_CAP_MASK;
+ else
+ mask = HT_5BIT_CAP_MASK;
+
+ pos = __pci_find_next_cap_ttl(dev->bus, dev->devfn, pos,
+ PCI_CAP_ID_HT, &ttl);
+ while (pos) {
+ rc = pci_read_config_byte(dev, pos + 3, &cap);
+ if (rc != PCIBIOS_SUCCESSFUL)
+ return 0;
+
+ if ((cap & mask) == ht_cap)
+ return pos;
+
+ pos = __pci_find_next_cap_ttl(dev->bus, dev->devfn, pos,
+ PCI_CAP_ID_HT, &ttl);
+ }
+
+ return 0;
+}
+/**
+ * pci_find_next_ht_capability - query a device's Hypertransport capabilities
+ * @dev: PCI device to query
+ * @pos: Position from which to continue searching
+ * @ht_cap: Hypertransport capability code
+ *
+ * To be used in conjunction with pci_find_ht_capability() to search for
+ * all capabilities matching @ht_cap. @pos should always be a value returned
+ * from pci_find_ht_capability().
+ *
+ * NB. To be 100% safe against broken PCI devices, the caller should take
+ * steps to avoid an infinite loop.
+ */
+int pci_find_next_ht_capability(struct pci_dev *dev, int pos, int ht_cap)
+{
+ return __pci_find_next_ht_cap(dev, pos + PCI_CAP_LIST_NEXT, ht_cap);
+}
+EXPORT_SYMBOL_GPL(pci_find_next_ht_capability);
+
+/**
+ * pci_find_ht_capability - query a device's Hypertransport capabilities
+ * @dev: PCI device to query
+ * @ht_cap: Hypertransport capability code
+ *
+ * Tell if a device supports a given Hypertransport capability.
+ * Returns an address within the device's PCI configuration space
+ * or 0 in case the device does not support the request capability.
+ * The address points to the PCI capability, of type PCI_CAP_ID_HT,
+ * which has a Hypertransport capability matching @ht_cap.
+ */
+int pci_find_ht_capability(struct pci_dev *dev, int ht_cap)
+{
+ int pos;
+
+ pos = __pci_bus_find_cap_start(dev->bus, dev->devfn, dev->hdr_type);
+ if (pos)
+ pos = __pci_find_next_ht_cap(dev, pos, ht_cap);
+
+ return pos;
+}
+EXPORT_SYMBOL_GPL(pci_find_ht_capability);
+
/**
* pci_find_parent_resource - return resource region of parent bus of given region
* @dev: PCI device structure contains resources to be searched