Certain platforms like TI's J721E using Cadence PCIe IP can perform only
32-bit accesses for reading or writing to Cadence registers. Convert all
read and write accesses to 32-bit in Cadence PCIe driver in preparation
for adding PCIe support in TI's J721E SoC.

Signed-off-by: Kishon Vijay Abraham I <kis...@ti.com>
---
 drivers/pci/controller/cadence/pcie-cadence.h | 71 ++++++++++++++-----
 1 file changed, 53 insertions(+), 18 deletions(-)

diff --git a/drivers/pci/controller/cadence/pcie-cadence.h 
b/drivers/pci/controller/cadence/pcie-cadence.h
index bc49c22e48a9..737e9561092b 100644
--- a/drivers/pci/controller/cadence/pcie-cadence.h
+++ b/drivers/pci/controller/cadence/pcie-cadence.h
@@ -319,50 +319,88 @@ struct cdns_pcie_ep {
 
 
 /* Register access */
-static inline void cdns_pcie_writeb(struct cdns_pcie *pcie, u32 reg, u8 value)
+static inline void cdns_pcie_writel(struct cdns_pcie *pcie, u32 reg, u32 value)
 {
-       writeb(value, pcie->reg_base + reg);
+       writel(value, pcie->reg_base + reg);
 }
 
-static inline void cdns_pcie_writew(struct cdns_pcie *pcie, u32 reg, u16 value)
+static inline u32 cdns_pcie_readl(struct cdns_pcie *pcie, u32 reg)
 {
-       writew(value, pcie->reg_base + reg);
+       return readl(pcie->reg_base + reg);
 }
 
-static inline void cdns_pcie_writel(struct cdns_pcie *pcie, u32 reg, u32 value)
+static inline u32 cdns_pcie_read_sz(void __iomem *addr, int size)
 {
-       writel(value, pcie->reg_base + reg);
+       void __iomem *aligned_addr = PTR_ALIGN_DOWN(addr, 0x4);
+       unsigned int offset = (unsigned long)addr & 0x3;
+       u32 val = readl(aligned_addr);
+
+       if (!IS_ALIGNED((uintptr_t)addr, size)) {
+               WARN(1, "Address %p and size %d are not aligned\n", addr, size);
+               return 0;
+       }
+
+       if (size > 2)
+               return val;
+
+       return (val >> (8 * offset)) & ((1 << (size * 8)) - 1);
 }
 
-static inline u32 cdns_pcie_readl(struct cdns_pcie *pcie, u32 reg)
+static inline void cdns_pcie_write_sz(void __iomem *addr, int size, u32 value)
 {
-       return readl(pcie->reg_base + reg);
+       void __iomem *aligned_addr = PTR_ALIGN_DOWN(addr, 0x4);
+       unsigned int offset = (unsigned long)addr & 0x3;
+       u32 mask;
+       u32 val;
+
+       if (!IS_ALIGNED((uintptr_t)addr, size)) {
+               WARN(1, "Address %p and size %d are not aligned\n", addr, size);
+               return;
+       }
+
+       if (size > 2) {
+               writel(value, addr);
+               return;
+       }
+
+       mask = ~(((1 << (size * 8)) - 1) << (offset * 8));
+       val = readl(aligned_addr) & mask;
+       val |= value << (offset * 8);
+       writel(val, aligned_addr);
 }
 
 /* Root Port register access */
 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;
+
+       cdns_pcie_write_sz(addr, 0x1, value);
 }
 
 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;
+
+       cdns_pcie_write_sz(addr, 0x2, value);
 }
 
 /* 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;
+
+       cdns_pcie_write_sz(addr, 0x1, value);
 }
 
 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;
+
+       cdns_pcie_write_sz(addr, 0x2, value);
 }
 
 static inline void cdns_pcie_ep_fn_writel(struct cdns_pcie *pcie, u8 fn,
@@ -371,14 +409,11 @@ static inline void cdns_pcie_ep_fn_writel(struct 
cdns_pcie *pcie, u8 fn,
        writel(value, pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg);
 }
 
-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);
-}
-
 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;
+
+       return cdns_pcie_read_sz(addr, 0x2);
 }
 
 static inline u32 cdns_pcie_ep_fn_readl(struct cdns_pcie *pcie, u8 fn, u32 reg)
-- 
2.17.1

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