dm: pci: Add APIs to find capability and extended capability
This introduces two new APIs dm_pci_find_capability() and
dm_pci_find_ext_capability() to get PCI capability address and
PCI express extended capability address for a given PCI device.
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/pci/pci-uclass.c b/drivers/pci/pci-uclass.c
index 5eb6841..e9671d9 100644
--- a/drivers/pci/pci-uclass.c
+++ b/drivers/pci/pci-uclass.c
@@ -1320,6 +1320,74 @@
return dm_pci_bus_to_virt(dev, pci_bus_addr, flags, 0, MAP_NOCACHE);
}
+int dm_pci_find_capability(struct udevice *dev, int cap)
+{
+ u16 status;
+ u8 header_type;
+ int ttl = PCI_FIND_CAP_TTL;
+ u8 id;
+ u16 ent;
+ u8 pos;
+
+ dm_pci_read_config16(dev, PCI_STATUS, &status);
+ if (!(status & PCI_STATUS_CAP_LIST))
+ return 0;
+
+ dm_pci_read_config8(dev, PCI_HEADER_TYPE, &header_type);
+ if ((header_type & 0x7f) == PCI_HEADER_TYPE_CARDBUS)
+ pos = PCI_CB_CAPABILITY_LIST;
+ else
+ pos = PCI_CAPABILITY_LIST;
+
+ dm_pci_read_config8(dev, pos, &pos);
+ while (ttl--) {
+ if (pos < PCI_STD_HEADER_SIZEOF)
+ break;
+ pos &= ~3;
+ dm_pci_read_config16(dev, pos, &ent);
+
+ id = ent & 0xff;
+ if (id == 0xff)
+ break;
+ if (id == cap)
+ return pos;
+ pos = (ent >> 8);
+ }
+
+ return 0;
+}
+
+int dm_pci_find_ext_capability(struct udevice *dev, int cap)
+{
+ u32 header;
+ int ttl;
+ int pos = PCI_CFG_SPACE_SIZE;
+
+ /* minimum 8 bytes per capability */
+ ttl = (PCI_CFG_SPACE_EXP_SIZE - PCI_CFG_SPACE_SIZE) / 8;
+
+ dm_pci_read_config32(dev, pos, &header);
+ /*
+ * If we have no capabilities, this is indicated by cap ID,
+ * cap version and next pointer all being 0.
+ */
+ if (header == 0)
+ return 0;
+
+ while (ttl--) {
+ if (PCI_EXT_CAP_ID(header) == cap)
+ return pos;
+
+ pos = PCI_EXT_CAP_NEXT(header);
+ if (pos < PCI_CFG_SPACE_SIZE)
+ break;
+
+ dm_pci_read_config32(dev, pos, &header);
+ }
+
+ return 0;
+}
+
UCLASS_DRIVER(pci) = {
.id = UCLASS_PCI,
.name = "pci",
diff --git a/include/pci.h b/include/pci.h
index 83a40a5..938a839 100644
--- a/include/pci.h
+++ b/include/pci.h
@@ -17,6 +17,7 @@
* Under PCI, each device has 256 bytes of configuration address space,
* of which the first 64 bytes are standardized as follows:
*/
+#define PCI_STD_HEADER_SIZEOF 64
#define PCI_VENDOR_ID 0x00 /* 16 bits */
#define PCI_DEVICE_ID 0x02 /* 16 bits */
#define PCI_COMMAND 0x04 /* 16 bits */
@@ -1311,6 +1312,51 @@
*/
void *dm_pci_map_bar(struct udevice *dev, int bar, int flags);
+/**
+ * dm_pci_find_capability() - find a capability
+ *
+ * Tell if a device supports a given PCI capability. Returns the
+ * address of the requested capability structure within the device's
+ * PCI configuration space or 0 in case the device does not support it.
+ *
+ * Possible values for @cap:
+ *
+ * %PCI_CAP_ID_MSI Message Signalled Interrupts
+ * %PCI_CAP_ID_PCIX PCI-X
+ * %PCI_CAP_ID_EXP PCI Express
+ * %PCI_CAP_ID_MSIX MSI-X
+ *
+ * See PCI_CAP_ID_xxx for the complete capability ID codes.
+ *
+ * @dev: PCI device to query
+ * @cap: capability code
+ * @return: capability address or 0 if not supported
+ */
+int dm_pci_find_capability(struct udevice *dev, int cap);
+
+/**
+ * dm_pci_find_ext_capability() - find an extended capability
+ *
+ * Tell if a device supports a given PCI express extended capability.
+ * Returns the address of the requested extended capability structure
+ * within the device's PCI configuration space or 0 in case the device
+ * does not support it.
+ *
+ * Possible values for @cap:
+ *
+ * %PCI_EXT_CAP_ID_ERR Advanced Error Reporting
+ * %PCI_EXT_CAP_ID_VC Virtual Channel
+ * %PCI_EXT_CAP_ID_DSN Device Serial Number
+ * %PCI_EXT_CAP_ID_PWR Power Budgeting
+ *
+ * See PCI_EXT_CAP_ID_xxx for the complete extended capability ID codes.
+ *
+ * @dev: PCI device to query
+ * @cap: extended capability code
+ * @return: extended capability address or 0 if not supported
+ */
+int dm_pci_find_ext_capability(struct udevice *dev, int cap);
+
#define dm_pci_virt_to_bus(dev, addr, flags) \
dm_pci_phys_to_bus(dev, (virt_to_phys(addr)), (flags))
#define dm_pci_bus_to_virt(dev, addr, flags, len, map_flags) \