Merge branch 'pci/capability-search'

- Simplify __pci_find_next_cap_ttl() by replacing magic numbers with
  #defines, extracting fields with FIELD_GET(), etc (Hans Zhang)

- Convert __pci_find_next_cap_ttl() to a PCI_FIND_NEXT_CAP() macro that
  takes a config space accessor function so we can also use it in cases
  where the usual config accessors aren't available (Hans Zhang)

- Similarly convert pci_find_next_ext_capability() to a
  PCI_FIND_NEXT_EXT_CAP() macro (Hans Zhang)

- Implement dwc, dwc endpoint, and cadence capability search interfaces on
  top of PCI_FIND_NEXT_CAP() and PCI_FIND_NEXT_EXT_CAP(), replacing the
  previous duplicated code (Hans Zhang)

- Search for capabilities in the cadence core instead of hard-coding their
  offsets, which are subject to change (Hans Zhang)

* pci/capability-search:
  PCI: cadence: Use cdns_pcie_find_*capability() to avoid hardcoding offsets
  PCI: cadence: Implement capability search using PCI core APIs
  PCI: dwc: ep: Implement capability search using PCI core APIs
  PCI: dwc: Implement capability search using PCI core APIs
  PCI: Refactor extended capability search into PCI_FIND_NEXT_EXT_CAP()
  PCI: Refactor capability search into PCI_FIND_NEXT_CAP()
  PCI: Clean up __pci_find_next_cap_ttl() readability

1 files changed, 10 insertions, 66 deletions

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 036511f5b262..f518cfa266b5 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -423,36 +423,10 @@ found:
 	return 1;
 }
 
-static u8 __pci_find_next_cap_ttl(struct pci_bus *bus, unsigned int devfn,
-				  u8 pos, int cap, int *ttl)
-{
-	u8 id;
-	u16 ent;
-
-	pci_bus_read_config_byte(bus, devfn, pos, &pos);
-
-	while ((*ttl)--) {
-		if (pos < 0x40)
-			break;
-		pos &= ~3;
-		pci_bus_read_config_word(bus, devfn, pos, &ent);
-
-		id = ent & 0xff;
-		if (id == 0xff)
-			break;
-		if (id == cap)
-			return pos;
-		pos = (ent >> 8);
-	}
-	return 0;
-}
-
 static u8 __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);
+	return PCI_FIND_NEXT_CAP(pci_bus_read_config, pos, cap, bus, devfn);
 }
 
 u8 pci_find_next_capability(struct pci_dev *dev, u8 pos, int cap)
@@ -553,42 +527,11 @@ EXPORT_SYMBOL(pci_bus_find_capability);
  */
 u16 pci_find_next_ext_capability(struct pci_dev *dev, u16 start, int cap)
 {
-	u32 header;
-	int ttl;
-	u16 pos = PCI_CFG_SPACE_SIZE;
-
-	/* minimum 8 bytes per capability */
-	ttl = (PCI_CFG_SPACE_EXP_SIZE - PCI_CFG_SPACE_SIZE) / 8;
-
 	if (dev->cfg_size <= PCI_CFG_SPACE_SIZE)
 		return 0;
 
-	if (start)
-		pos = start;
-
-	if (pci_read_config_dword(dev, pos, &header) != PCIBIOS_SUCCESSFUL)
-		return 0;
-
-	/*
-	 * 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-- > 0) {
-		if (PCI_EXT_CAP_ID(header) == cap && pos != start)
-			return pos;
-
-		pos = PCI_EXT_CAP_NEXT(header);
-		if (pos < PCI_CFG_SPACE_SIZE)
-			break;
-
-		if (pci_read_config_dword(dev, pos, &header) != PCIBIOS_SUCCESSFUL)
-			break;
-	}
-
-	return 0;
+	return PCI_FIND_NEXT_EXT_CAP(pci_bus_read_config, start, cap,
+				     dev->bus, dev->devfn);
 }
 EXPORT_SYMBOL_GPL(pci_find_next_ext_capability);
 
@@ -648,7 +591,7 @@ EXPORT_SYMBOL_GPL(pci_get_dsn);
 
 static u8 __pci_find_next_ht_cap(struct pci_dev *dev, u8 pos, int ht_cap)
 {
-	int rc, ttl = PCI_FIND_CAP_TTL;
+	int rc;
 	u8 cap, mask;
 
 	if (ht_cap == HT_CAPTYPE_SLAVE || ht_cap == HT_CAPTYPE_HOST)
@@ -656,8 +599,8 @@ static u8 __pci_find_next_ht_cap(struct pci_dev *dev, u8 pos, int ht_cap)
 	else
 		mask = HT_5BIT_CAP_MASK;
 
-	pos = __pci_find_next_cap_ttl(dev->bus, dev->devfn, pos,
-				      PCI_CAP_ID_HT, &ttl);
+	pos = PCI_FIND_NEXT_CAP(pci_bus_read_config, pos,
+				PCI_CAP_ID_HT, dev->bus, dev->devfn);
 	while (pos) {
 		rc = pci_read_config_byte(dev, pos + 3, &cap);
 		if (rc != PCIBIOS_SUCCESSFUL)
@@ -666,9 +609,10 @@ static u8 __pci_find_next_ht_cap(struct pci_dev *dev, u8 pos, int ht_cap)
 		if ((cap & mask) == ht_cap)
 			return pos;
 
-		pos = __pci_find_next_cap_ttl(dev->bus, dev->devfn,
-					      pos + PCI_CAP_LIST_NEXT,
-					      PCI_CAP_ID_HT, &ttl);
+		pos = PCI_FIND_NEXT_CAP(pci_bus_read_config,
+					pos + PCI_CAP_LIST_NEXT,
+					PCI_CAP_ID_HT, dev->bus,
+					dev->devfn);
 	}
 
 	return 0;