[PATCH 03/13] PCI: cadence: Add support to use custom read and write accessors

[Kishon Vijay Abraham I <kishon@ti.com>]

Add support to use custom read and write accessors. Platforms that
doesn't support half word or byte access or any other constraint
while accessing registers can use this feature to populate custom
read and write accessors. These custom accessors are used for both
standard register access and configuration space register access.
This is in preparation for adding PCIe support in TI's J721E SoC which
uses Cadence PCIe core.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
---
 drivers/pci/controller/cadence/pcie-cadence.h | 99 +++++++++++++++++--
 1 file changed, 90 insertions(+), 9 deletions(-)

diff --git a/drivers/pci/controller/cadence/pcie-cadence.h b/drivers/pci/controller/cadence/pcie-cadence.h
index a2b28b912ca4..d0d91c69fa1d 100644
--- a/drivers/pci/controller/cadence/pcie-cadence.h
+++ b/drivers/pci/controller/cadence/pcie-cadence.h
@@ -223,6 +223,11 @@ enum cdns_pcie_msg_routing {
 	MSG_ROUTING_GATHER,
 };
 
+struct cdns_pcie_ops {
+	u32	(*read)(void __iomem *addr, int size);
+	void	(*write)(void __iomem *addr, int size, u32 value);
+};
+
 /**
  * struct cdns_pcie - private data for Cadence PCIe controller drivers
  * @reg_base: IO mapped register base
@@ -239,7 +244,7 @@ struct cdns_pcie {
 	int			phy_count;
 	struct phy		**phy;
 	struct device_link	**link;
-	const struct cdns_pcie_common_ops *ops;
+	const struct cdns_pcie_ops *ops;
 };
 
 /**
@@ -301,21 +306,47 @@ struct cdns_pcie_ep {
 /* Register access */
 static inline void cdns_pcie_writeb(struct cdns_pcie *pcie, u32 reg, u8 value)
 {
+	void __iomem *addr = pcie->reg_base + reg;
+
+	if (pcie->ops && pcie->ops->write) {
+		pcie->ops->write(addr, 0x1, value);
+		return;
+	}
+
 	writeb(value, pcie->reg_base + reg);
 }
 
 static inline void cdns_pcie_writew(struct cdns_pcie *pcie, u32 reg, u16 value)
 {
+	void __iomem *addr = pcie->reg_base + reg;
+
+	if (pcie->ops && pcie->ops->write) {
+		pcie->ops->write(addr, 0x2, value);
+		return;
+	}
+
 	writew(value, pcie->reg_base + reg);
 }
 
 static inline void cdns_pcie_writel(struct cdns_pcie *pcie, u32 reg, u32 value)
 {
+	void __iomem *addr = pcie->reg_base + reg;
+
+	if (pcie->ops && pcie->ops->write) {
+		pcie->ops->write(addr, 0x4, value);
+		return;
+	}
+
 	writel(value, pcie->reg_base + reg);
 }
 
 static inline u32 cdns_pcie_readl(struct cdns_pcie *pcie, u32 reg)
 {
+	void __iomem *addr = pcie->reg_base + reg;
+
+	if (pcie->ops && pcie->ops->read)
+		return pcie->ops->read(addr, 0x4);
+
 	return readl(pcie->reg_base + reg);
 }
 
@@ -323,47 +354,97 @@ static inline u32 cdns_pcie_readl(struct cdns_pcie *pcie, u32 reg)
 static inline void cdns_pcie_rp_writeb(struct cdns_pcie *pcie,
 				       u32 reg, u8 value)
 {
-	writeb(value, pcie->reg_base + CDNS_PCIE_RP_BASE + reg);
+	void __iomem *addr = pcie->reg_base + CDNS_PCIE_RP_BASE + reg;
+
+	if (pcie->ops && pcie->ops->write) {
+		pcie->ops->write(addr, 0x1, value);
+		return;
+	}
+
+	writeb(value, addr);
 }
 
 static inline void cdns_pcie_rp_writew(struct cdns_pcie *pcie,
 				       u32 reg, u16 value)
 {
-	writew(value, pcie->reg_base + CDNS_PCIE_RP_BASE + reg);
+	void __iomem *addr = pcie->reg_base + CDNS_PCIE_RP_BASE + reg;
+
+	if (pcie->ops && pcie->ops->write) {
+		pcie->ops->write(addr, 0x2, value);
+		return;
+	}
+
+	writew(value, addr);
 }
 
 /* Endpoint Function register access */
 static inline void cdns_pcie_ep_fn_writeb(struct cdns_pcie *pcie, u8 fn,
 					  u32 reg, u8 value)
 {
-	writeb(value, pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg);
+	void __iomem *addr = pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg;
+
+	if (pcie->ops && pcie->ops->write) {
+		pcie->ops->write(addr, 0x1, value);
+		return;
+	}
+
+	writeb(value, addr);
 }
 
 static inline void cdns_pcie_ep_fn_writew(struct cdns_pcie *pcie, u8 fn,
 					  u32 reg, u16 value)
 {
-	writew(value, pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg);
+	void __iomem *addr = pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg;
+
+	if (pcie->ops && pcie->ops->write) {
+		pcie->ops->write(addr, 0x2, value);
+		return;
+	}
+
+	writew(value, addr);
 }
 
 static inline void cdns_pcie_ep_fn_writel(struct cdns_pcie *pcie, u8 fn,
 					  u32 reg, u32 value)
 {
-	writel(value, pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg);
+	void __iomem *addr = pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg;
+
+	if (pcie->ops && pcie->ops->write) {
+		pcie->ops->write(addr, 0x4, value);
+		return;
+	}
+
+	writel(value, addr);
 }
 
 static inline u8 cdns_pcie_ep_fn_readb(struct cdns_pcie *pcie, u8 fn, u32 reg)
 {
-	return readb(pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg);
+	void __iomem *addr = pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg;
+
+	if (pcie->ops && pcie->ops->read)
+		return pcie->ops->read(addr, 0x1);
+
+	return readb(addr);
 }
 
 static inline u16 cdns_pcie_ep_fn_readw(struct cdns_pcie *pcie, u8 fn, u32 reg)
 {
-	return readw(pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg);
+	void __iomem *addr = pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg;
+
+	if (pcie->ops && pcie->ops->read)
+		return pcie->ops->read(addr, 0x2);
+
+	return readw(addr);
 }
 
 static inline u32 cdns_pcie_ep_fn_readl(struct cdns_pcie *pcie, u8 fn, u32 reg)
 {
-	return readl(pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg);
+	void __iomem *addr = pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg;
+
+	if (pcie->ops && pcie->ops->read)
+		return pcie->ops->read(addr, 0x4);
+
+	return readl(addr);
 }
 
 #ifdef CONFIG_PCIE_CADENCE_HOST
-- 
2.17.1