[PATCH V4 05/16] PCI: dwc: Move config space capability search API

[Vidya Sagar <vidyas@nvidia.com>]

Move PCIe config space capability search API to common DesignWare file
as this can be used by both host and ep mode codes.

Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
Acked-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
---
Changes from [v3]:
* Rebased to linux-next top of the tree

Changes from [v2]:
* None

Changes from [v1]:
* Removed dw_pcie_find_next_ext_capability() API from here and made a
  separate patch for that

 drivers/pci/controller/dwc/pcie-designware.c | 33 ++++++++++++++++++++
 drivers/pci/controller/dwc/pcie-designware.h |  2 ++
 2 files changed, 35 insertions(+)

diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c
index 8e0081ccf83b..6a98135244d6 100644
--- a/drivers/pci/controller/dwc/pcie-designware.c
+++ b/drivers/pci/controller/dwc/pcie-designware.c
@@ -20,6 +20,39 @@
 #define PCIE_PHY_DEBUG_R1_LINK_UP	(0x1 << 4)
 #define PCIE_PHY_DEBUG_R1_LINK_IN_TRAINING	(0x1 << 29)
 
+static u8 __dw_pcie_find_next_cap(struct dw_pcie *pci, u8 cap_ptr,
+				  u8 cap)
+{
+	u8 cap_id, next_cap_ptr;
+	u16 reg;
+
+	reg = dw_pcie_readw_dbi(pci, cap_ptr);
+	next_cap_ptr = (reg & 0xff00) >> 8;
+	cap_id = (reg & 0x00ff);
+
+	if (!next_cap_ptr || cap_id > PCI_CAP_ID_MAX)
+		return 0;
+
+	if (cap_id == cap)
+		return cap_ptr;
+
+	return __dw_pcie_find_next_cap(pci, next_cap_ptr, cap);
+}
+
+u8 dw_pcie_find_capability(struct dw_pcie *pci, u8 cap)
+{
+	u8 next_cap_ptr;
+	u16 reg;
+
+	reg = dw_pcie_readw_dbi(pci, PCI_CAPABILITY_LIST);
+	next_cap_ptr = (reg & 0x00ff);
+
+	if (!next_cap_ptr)
+		return 0;
+
+	return __dw_pcie_find_next_cap(pci, next_cap_ptr, cap);
+}
+
 int dw_pcie_read(void __iomem *addr, int size, u32 *val)
 {
 	if (!IS_ALIGNED((uintptr_t)addr, size)) {
diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
index 9ee98ced1ef6..35160b4ce929 100644
--- a/drivers/pci/controller/dwc/pcie-designware.h
+++ b/drivers/pci/controller/dwc/pcie-designware.h
@@ -248,6 +248,8 @@ struct dw_pcie {
 #define to_dw_pcie_from_ep(endpoint)   \
 		container_of((endpoint), struct dw_pcie, ep)
 
+u8 dw_pcie_find_capability(struct dw_pcie *pci, u8 cap);
+
 int dw_pcie_read(void __iomem *addr, int size, u32 *val);
 int dw_pcie_write(void __iomem *addr, int size, u32 val);
 
-- 
2.17.1