diff --git a/arch/powerpc/platforms/4xx/pci.c b/arch/powerpc/platforms/4xx/pci.c
index c13d64c3b019..4f3c529ef3b9 100644
--- a/arch/powerpc/platforms/4xx/pci.c
+++ b/arch/powerpc/platforms/4xx/pci.c
@@ -20,6 +20,7 @@
 
 #include <linux/kernel.h>
 #include <linux/pci.h>
+#include <linux/pci-ecam.h>
 #include <linux/init.h>
 #include <linux/of.h>
 #include <linux/delay.h>
@@ -1583,9 +1584,10 @@ static int ppc4xx_pciex_validate_bdf(struct ppc4xx_pciex_port *port,
 
 static void __iomem *ppc4xx_pciex_get_config_base(struct ppc4xx_pciex_port *port,
 						  struct pci_bus *bus,
-						  unsigned int devfn)
+						  unsigned int devfn,
+						  int offset)
 {
-	int relbus;
+	unsigned int busnr_ecam = bus->number - (port->hose->first_busno + 1);
 
 	/* Remove the casts when we finally remove the stupid volatile
 	 * in struct pci_controller
@@ -1593,9 +1595,7 @@ static void __iomem *ppc4xx_pciex_get_config_base(struct ppc4xx_pciex_port *port
 	if (bus->number == port->hose->first_busno)
 		return (void __iomem *)port->hose->cfg_addr;
 
-	relbus = bus->number - (port->hose->first_busno + 1);
-	return (void __iomem *)port->hose->cfg_data +
-		((relbus  << 20) | (devfn << 12));
+	return port->hose->cfg_data + PCIE_ECAM_OFFSET(busnr_ecam, devfn, offset);
 }
 
 static int ppc4xx_pciex_read_config(struct pci_bus *bus, unsigned int devfn,
@@ -1612,7 +1612,7 @@ static int ppc4xx_pciex_read_config(struct pci_bus *bus, unsigned int devfn,
 	if (ppc4xx_pciex_validate_bdf(port, bus, devfn) != 0)
 		return PCIBIOS_DEVICE_NOT_FOUND;
 
-	addr = ppc4xx_pciex_get_config_base(port, bus, devfn);
+	addr = ppc4xx_pciex_get_config_base(port, bus, devfn, offset);
 
 	/*
 	 * Reading from configuration space of non-existing device can
@@ -1627,20 +1627,20 @@ static int ppc4xx_pciex_read_config(struct pci_bus *bus, unsigned int devfn,
 
 	switch (len) {
 	case 1:
-		*val = in_8((u8 *)(addr + offset));
+		*val = in_8((u8 *)addr);
 		break;
 	case 2:
-		*val = in_le16((u16 *)(addr + offset));
+		*val = in_le16((u16 *)addr);
 		break;
 	default:
-		*val = in_le32((u32 *)(addr + offset));
+		*val = in_le32((u32 *)addr);
 		break;
 	}
 
 	pr_debug("pcie-config-read: bus=%3d [%3d..%3d] devfn=0x%04x"
 		 " offset=0x%04x len=%d, addr=0x%p val=0x%08x\n",
 		 bus->number, hose->first_busno, hose->last_busno,
-		 devfn, offset, len, addr + offset, *val);
+		 devfn, offset, len, addr, *val);
 
 	/* Check for CRS (440SPe rev B does that for us but heh ..) */
 	if (in_be32(port->utl_base + PEUTL_RCSTA) & 0x00040000) {
@@ -1667,7 +1667,7 @@ static int ppc4xx_pciex_write_config(struct pci_bus *bus, unsigned int devfn,
 	if (ppc4xx_pciex_validate_bdf(port, bus, devfn) != 0)
 		return PCIBIOS_DEVICE_NOT_FOUND;
 
-	addr = ppc4xx_pciex_get_config_base(port, bus, devfn);
+	addr = ppc4xx_pciex_get_config_base(port, bus, devfn, offset);
 
 	/*
 	 * Reading from configuration space of non-existing device can
@@ -1680,17 +1680,17 @@ static int ppc4xx_pciex_write_config(struct pci_bus *bus, unsigned int devfn,
 	pr_debug("pcie-config-write: bus=%3d [%3d..%3d] devfn=0x%04x"
 		 " offset=0x%04x len=%d, addr=0x%p val=0x%08x\n",
 		 bus->number, hose->first_busno, hose->last_busno,
-		 devfn, offset, len, addr + offset, val);
+		 devfn, offset, len, addr, val);
 
 	switch (len) {
 	case 1:
-		out_8((u8 *)(addr + offset), val);
+		out_8((u8 *)addr, val);
 		break;
 	case 2:
-		out_le16((u16 *)(addr + offset), val);
+		out_le16((u16 *)addr, val);
 		break;
 	default:
-		out_le32((u32 *)(addr + offset), val);
+		out_le32((u32 *)addr, val);
 		break;
 	}
 
diff --git a/drivers/pci/controller/dwc/pcie-al.c b/drivers/pci/controller/dwc/pcie-al.c
index f973fbca90cf..979d93b82df2 100644
--- a/drivers/pci/controller/dwc/pcie-al.c
+++ b/drivers/pci/controller/dwc/pcie-al.c
@@ -76,7 +76,7 @@ static int al_pcie_init(struct pci_config_window *cfg)
 }
 
 const struct pci_ecam_ops al_pcie_ops = {
-	.bus_shift    = 20,
+	.bus_shift    = PCIE_ECAM_BUS_SHIFT,
 	.init         =  al_pcie_init,
 	.pci_ops      = {
 		.map_bus    = al_pcie_map_bus,
@@ -138,8 +138,6 @@ struct al_pcie {
 	struct al_pcie_target_bus_cfg target_bus_cfg;
 };
 
-#define PCIE_ECAM_DEVFN(x)		(((x) & 0xff) << 12)
-
 #define to_al_pcie(x)		dev_get_drvdata((x)->dev)
 
 static inline u32 al_pcie_controller_readl(struct al_pcie *pcie, u32 offset)
@@ -226,11 +224,6 @@ static void __iomem *al_pcie_conf_addr_map_bus(struct pci_bus *bus,
 	struct al_pcie_target_bus_cfg *target_bus_cfg = &pcie->target_bus_cfg;
 	unsigned int busnr_ecam = busnr & target_bus_cfg->ecam_mask;
 	unsigned int busnr_reg = busnr & target_bus_cfg->reg_mask;
-	void __iomem *pci_base_addr;
-
-	pci_base_addr = (void __iomem *)((uintptr_t)pp->va_cfg0_base +
-					 (busnr_ecam << 20) +
-					 PCIE_ECAM_DEVFN(devfn));
 
 	if (busnr_reg != target_bus_cfg->reg_val) {
 		dev_dbg(pcie->pci->dev, "Changing target bus busnum val from 0x%x to 0x%x\n",
@@ -241,7 +234,7 @@ static void __iomem *al_pcie_conf_addr_map_bus(struct pci_bus *bus,
 				       target_bus_cfg->reg_mask);
 	}
 
-	return pci_base_addr + where;
+	return pp->va_cfg0_base + PCIE_ECAM_OFFSET(busnr_ecam, devfn, where);
 }
 
 static struct pci_ops al_child_pci_ops = {
@@ -264,7 +257,7 @@ static void al_pcie_config_prepare(struct al_pcie *pcie)
 
 	target_bus_cfg = &pcie->target_bus_cfg;
 
-	ecam_bus_mask = (pcie->ecam_size >> 20) - 1;
+	ecam_bus_mask = (pcie->ecam_size >> PCIE_ECAM_BUS_SHIFT) - 1;
 	if (ecam_bus_mask > 255) {
 		dev_warn(pcie->dev, "ECAM window size is larger than 256MB. Cutting off at 256\n");
 		ecam_bus_mask = 255;
diff --git a/drivers/pci/controller/dwc/pcie-hisi.c b/drivers/pci/controller/dwc/pcie-hisi.c
index 5ca86796d43a..b7afbf1d4bd9 100644
--- a/drivers/pci/controller/dwc/pcie-hisi.c
+++ b/drivers/pci/controller/dwc/pcie-hisi.c
@@ -100,7 +100,7 @@ static int hisi_pcie_init(struct pci_config_window *cfg)
 }
 
 const struct pci_ecam_ops hisi_pcie_ops = {
-	.bus_shift    = 20,
+	.bus_shift    = PCIE_ECAM_BUS_SHIFT,
 	.init         =  hisi_pcie_init,
 	.pci_ops      = {
 		.map_bus    = hisi_pcie_map_bus,
@@ -135,7 +135,7 @@ static int hisi_pcie_platform_init(struct pci_config_window *cfg)
 }
 
 static const struct pci_ecam_ops hisi_pcie_platform_ops = {
-	.bus_shift    = 20,
+	.bus_shift    = PCIE_ECAM_BUS_SHIFT,
 	.init         =  hisi_pcie_platform_init,
 	.pci_ops      = {
 		.map_bus    = hisi_pcie_map_bus,
diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c
index 0be485a25327..1043e54c73bd 100644
--- a/drivers/pci/controller/pci-aardvark.c
+++ b/drivers/pci/controller/pci-aardvark.c
@@ -16,6 +16,7 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/pci.h>
+#include <linux/pci-ecam.h>
 #include <linux/init.h>
 #include <linux/phy/phy.h>
 #include <linux/platform_device.h>
@@ -164,14 +165,6 @@
 #define PCIE_CONFIG_WR_TYPE0			0xa
 #define PCIE_CONFIG_WR_TYPE1			0xb
 
-#define PCIE_CONF_BUS(bus)			(((bus) & 0xff) << 20)
-#define PCIE_CONF_DEV(dev)			(((dev) & 0x1f) << 15)
-#define PCIE_CONF_FUNC(fun)			(((fun) & 0x7)	<< 12)
-#define PCIE_CONF_REG(reg)			((reg) & 0xffc)
-#define PCIE_CONF_ADDR(bus, devfn, where)	\
-	(PCIE_CONF_BUS(bus) | PCIE_CONF_DEV(PCI_SLOT(devfn))	| \
-	 PCIE_CONF_FUNC(PCI_FUNC(devfn)) | PCIE_CONF_REG(where))
-
 #define PIO_RETRY_CNT			500
 #define PIO_RETRY_DELAY			2 /* 2 us*/
 
@@ -687,7 +680,7 @@ static int advk_pcie_rd_conf(struct pci_bus *bus, u32 devfn,
 	advk_writel(pcie, reg, PIO_CTRL);
 
 	/* Program the address registers */
-	reg = PCIE_CONF_ADDR(bus->number, devfn, where);
+	reg = ALIGN_DOWN(PCIE_ECAM_OFFSET(bus->number, devfn, where), 4);
 	advk_writel(pcie, reg, PIO_ADDR_LS);
 	advk_writel(pcie, 0, PIO_ADDR_MS);
 
@@ -748,7 +741,7 @@ static int advk_pcie_wr_conf(struct pci_bus *bus, u32 devfn,
 	advk_writel(pcie, reg, PIO_CTRL);
 
 	/* Program the address registers */
-	reg = PCIE_CONF_ADDR(bus->number, devfn, where);
+	reg = ALIGN_DOWN(PCIE_ECAM_OFFSET(bus->number, devfn, where), 4);
 	advk_writel(pcie, reg, PIO_ADDR_LS);
 	advk_writel(pcie, 0, PIO_ADDR_MS);
 
diff --git a/drivers/pci/controller/pci-host-generic.c b/drivers/pci/controller/pci-host-generic.c
index b51977abfdf1..c1c69b11615f 100644
--- a/drivers/pci/controller/pci-host-generic.c
+++ b/drivers/pci/controller/pci-host-generic.c
@@ -49,7 +49,7 @@ static void __iomem *pci_dw_ecam_map_bus(struct pci_bus *bus,
 }
 
 static const struct pci_ecam_ops pci_dw_ecam_bus_ops = {
-	.bus_shift	= 20,
+	.bus_shift	= PCIE_ECAM_BUS_SHIFT,
 	.pci_ops	= {
 		.map_bus	= pci_dw_ecam_map_bus,
 		.read		= pci_generic_config_read,
diff --git a/drivers/pci/controller/pci-thunder-ecam.c b/drivers/pci/controller/pci-thunder-ecam.c
index 7e8835fee5f7..22ed7e995b39 100644
--- a/drivers/pci/controller/pci-thunder-ecam.c
+++ b/drivers/pci/controller/pci-thunder-ecam.c
@@ -346,7 +346,7 @@ static int thunder_ecam_config_write(struct pci_bus *bus, unsigned int devfn,
 }
 
 const struct pci_ecam_ops pci_thunder_ecam_ops = {
-	.bus_shift	= 20,
+	.bus_shift	= PCIE_ECAM_BUS_SHIFT,
 	.pci_ops	= {
 		.map_bus        = pci_ecam_map_bus,
 		.read           = thunder_ecam_config_read,
diff --git a/drivers/pci/controller/pci-thunder-pem.c b/drivers/pci/controller/pci-thunder-pem.c
index 3f847969143e..1a3f70ac61fc 100644
--- a/drivers/pci/controller/pci-thunder-pem.c
+++ b/drivers/pci/controller/pci-thunder-pem.c
@@ -19,6 +19,15 @@
 #define PEM_CFG_WR 0x28
 #define PEM_CFG_RD 0x30
 
+/*
+ * Enhanced Configuration Access Mechanism (ECAM)
+ *
+ * N.B. This is a non-standard platform-specific ECAM bus shift value.  For
+ * standard values defined in the PCI Express Base Specification see
+ * include/linux/pci-ecam.h.
+ */
+#define THUNDER_PCIE_ECAM_BUS_SHIFT	24
+
 struct thunder_pem_pci {
 	u32		ea_entry[3];
 	void __iomem	*pem_reg_base;
@@ -404,7 +413,7 @@ static int thunder_pem_acpi_init(struct pci_config_window *cfg)
 }
 
 const struct pci_ecam_ops thunder_pem_ecam_ops = {
-	.bus_shift	= 24,
+	.bus_shift	= THUNDER_PCIE_ECAM_BUS_SHIFT,
 	.init		= thunder_pem_acpi_init,
 	.pci_ops	= {
 		.map_bus	= pci_ecam_map_bus,
@@ -441,7 +450,7 @@ static int thunder_pem_platform_init(struct pci_config_window *cfg)
 }
 
 static const struct pci_ecam_ops pci_thunder_pem_ops = {
-	.bus_shift	= 24,
+	.bus_shift	= THUNDER_PCIE_ECAM_BUS_SHIFT,
 	.init		= thunder_pem_platform_init,
 	.pci_ops	= {
 		.map_bus	= pci_ecam_map_bus,
diff --git a/drivers/pci/controller/pci-xgene.c b/drivers/pci/controller/pci-xgene.c
index 8e0db84f089d..85e7c98265e8 100644
--- a/drivers/pci/controller/pci-xgene.c
+++ b/drivers/pci/controller/pci-xgene.c
@@ -257,7 +257,6 @@ static int xgene_v1_pcie_ecam_init(struct pci_config_window *cfg)
 }
 
 const struct pci_ecam_ops xgene_v1_pcie_ecam_ops = {
-	.bus_shift	= 16,
 	.init		= xgene_v1_pcie_ecam_init,
 	.pci_ops	= {
 		.map_bus	= xgene_pcie_map_bus,
@@ -272,7 +271,6 @@ static int xgene_v2_pcie_ecam_init(struct pci_config_window *cfg)
 }
 
 const struct pci_ecam_ops xgene_v2_pcie_ecam_ops = {
-	.bus_shift	= 16,
 	.init		= xgene_v2_pcie_ecam_init,
 	.pci_ops	= {
 		.map_bus	= xgene_pcie_map_bus,
diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
index bea86899bd5d..7fc80fd6f13f 100644
--- a/drivers/pci/controller/pcie-brcmstb.c
+++ b/drivers/pci/controller/pcie-brcmstb.c
@@ -22,6 +22,7 @@
 #include <linux/of_pci.h>
 #include <linux/of_platform.h>
 #include <linux/pci.h>
+#include <linux/pci-ecam.h>
 #include <linux/printk.h>
 #include <linux/reset.h>
 #include <linux/sizes.h>
@@ -127,11 +128,7 @@
 #define  MSI_INT_MASK_CLR		0x14
 
 #define PCIE_EXT_CFG_DATA				0x8000
-
 #define PCIE_EXT_CFG_INDEX				0x9000
-#define  PCIE_EXT_BUSNUM_SHIFT				20
-#define  PCIE_EXT_SLOT_SHIFT				15
-#define  PCIE_EXT_FUNC_SHIFT				12
 
 #define  PCIE_RGR1_SW_INIT_1_PERST_MASK			0x1
 #define  PCIE_RGR1_SW_INIT_1_PERST_SHIFT		0x0
@@ -695,15 +692,6 @@ static bool brcm_pcie_link_up(struct brcm_pcie *pcie)
 	return dla && plu;
 }
 
-/* Configuration space read/write support */
-static inline int brcm_pcie_cfg_index(int busnr, int devfn, int reg)
-{
-	return ((PCI_SLOT(devfn) & 0x1f) << PCIE_EXT_SLOT_SHIFT)
-		| ((PCI_FUNC(devfn) & 0x07) << PCIE_EXT_FUNC_SHIFT)
-		| (busnr << PCIE_EXT_BUSNUM_SHIFT)
-		| (reg & ~3);
-}
-
 static void __iomem *brcm_pcie_map_conf(struct pci_bus *bus, unsigned int devfn,
 					int where)
 {
@@ -716,7 +704,7 @@ static void __iomem *brcm_pcie_map_conf(struct pci_bus *bus, unsigned int devfn,
 		return PCI_SLOT(devfn) ? NULL : base + where;
 
 	/* For devices, write to the config space index register */
-	idx = brcm_pcie_cfg_index(bus->number, devfn, 0);
+	idx = PCIE_ECAM_OFFSET(bus->number, devfn, 0);
 	writel(idx, pcie->base + PCIE_EXT_CFG_INDEX);
 	return base + PCIE_EXT_CFG_DATA + where;
 }
diff --git a/drivers/pci/controller/pcie-iproc.c b/drivers/pci/controller/pcie-iproc.c
index 905e93808243..503662380ff8 100644
--- a/drivers/pci/controller/pcie-iproc.c
+++ b/drivers/pci/controller/pcie-iproc.c
@@ -6,6 +6,7 @@
 
 #include <linux/kernel.h>
 #include <linux/pci.h>
+#include <linux/pci-ecam.h>
 #include <linux/msi.h>
 #include <linux/clk.h>
 #include <linux/module.h>
@@ -39,16 +40,8 @@
 
 #define CFG_IND_ADDR_MASK		0x00001ffc
 
-#define CFG_ADDR_BUS_NUM_SHIFT		20
-#define CFG_ADDR_BUS_NUM_MASK		0x0ff00000
-#define CFG_ADDR_DEV_NUM_SHIFT		15
-#define CFG_ADDR_DEV_NUM_MASK		0x000f8000
-#define CFG_ADDR_FUNC_NUM_SHIFT		12
-#define CFG_ADDR_FUNC_NUM_MASK		0x00007000
-#define CFG_ADDR_REG_NUM_SHIFT		2
 #define CFG_ADDR_REG_NUM_MASK		0x00000ffc
-#define CFG_ADDR_CFG_TYPE_SHIFT		0
-#define CFG_ADDR_CFG_TYPE_MASK		0x00000003
+#define CFG_ADDR_CFG_TYPE_1		1
 
 #define SYS_RC_INTX_MASK		0xf
 
@@ -459,19 +452,15 @@ static inline void iproc_pcie_apb_err_disable(struct pci_bus *bus,
 
 static void __iomem *iproc_pcie_map_ep_cfg_reg(struct iproc_pcie *pcie,
 					       unsigned int busno,
-					       unsigned int slot,
-					       unsigned int fn,
+					       unsigned int devfn,
 					       int where)
 {
 	u16 offset;
 	u32 val;
 
 	/* EP device access */
-	val = (busno << CFG_ADDR_BUS_NUM_SHIFT) |
-		(slot << CFG_ADDR_DEV_NUM_SHIFT) |
-		(fn << CFG_ADDR_FUNC_NUM_SHIFT) |
-		(where & CFG_ADDR_REG_NUM_MASK) |
-		(1 & CFG_ADDR_CFG_TYPE_MASK);
+	val = ALIGN_DOWN(PCIE_ECAM_OFFSET(busno, devfn, where), 4) |
+		CFG_ADDR_CFG_TYPE_1;
 
 	iproc_pcie_write_reg(pcie, IPROC_PCIE_CFG_ADDR, val);
 	offset = iproc_pcie_reg_offset(pcie, IPROC_PCIE_CFG_DATA);
@@ -574,8 +563,6 @@ static int iproc_pcie_config_read(struct pci_bus *bus, unsigned int devfn,
 				  int where, int size, u32 *val)
 {
 	struct iproc_pcie *pcie = iproc_data(bus);
-	unsigned int slot = PCI_SLOT(devfn);
-	unsigned int fn = PCI_FUNC(devfn);
 	unsigned int busno = bus->number;
 	void __iomem *cfg_data_p;
 	unsigned int data;
@@ -590,7 +577,7 @@ static int iproc_pcie_config_read(struct pci_bus *bus, unsigned int devfn,
 		return ret;
 	}
 
-	cfg_data_p = iproc_pcie_map_ep_cfg_reg(pcie, busno, slot, fn, where);
+	cfg_data_p = iproc_pcie_map_ep_cfg_reg(pcie, busno, devfn, where);
 
 	if (!cfg_data_p)
 		return PCIBIOS_DEVICE_NOT_FOUND;
@@ -631,13 +618,11 @@ static void __iomem *iproc_pcie_map_cfg_bus(struct iproc_pcie *pcie,
 					    int busno, unsigned int devfn,
 					    int where)
 {
-	unsigned slot = PCI_SLOT(devfn);
-	unsigned fn = PCI_FUNC(devfn);
 	u16 offset;
 
 	/* root complex access */
 	if (busno == 0) {
-		if (slot > 0 || fn > 0)
+		if (PCIE_ECAM_DEVFN(devfn) > 0)
 			return NULL;
 
 		iproc_pcie_write_reg(pcie, IPROC_PCIE_CFG_IND_ADDR,
@@ -649,7 +634,7 @@ static void __iomem *iproc_pcie_map_cfg_bus(struct iproc_pcie *pcie,
 			return (pcie->base + offset);
 	}
 
-	return iproc_pcie_map_ep_cfg_reg(pcie, busno, slot, fn, where);
+	return iproc_pcie_map_ep_cfg_reg(pcie, busno, devfn, where);
 }
 
 static void __iomem *iproc_pcie_bus_map_cfg_bus(struct pci_bus *bus,
diff --git a/drivers/pci/controller/pcie-rockchip-host.c b/drivers/pci/controller/pcie-rockchip-host.c
index 9705059523a6..f1d08a1b1591 100644
--- a/drivers/pci/controller/pcie-rockchip-host.c
+++ b/drivers/pci/controller/pcie-rockchip-host.c
@@ -157,12 +157,11 @@ static int rockchip_pcie_rd_other_conf(struct rockchip_pcie *rockchip,
 				       struct pci_bus *bus, u32 devfn,
 				       int where, int size, u32 *val)
 {
-	u32 busdev;
+	void __iomem *addr;
 
-	busdev = PCIE_ECAM_ADDR(bus->number, PCI_SLOT(devfn),
-				PCI_FUNC(devfn), where);
+	addr = rockchip->reg_base + PCIE_ECAM_OFFSET(bus->number, devfn, where);
 
-	if (!IS_ALIGNED(busdev, size)) {
+	if (!IS_ALIGNED((uintptr_t)addr, size)) {
 		*val = 0;
 		return PCIBIOS_BAD_REGISTER_NUMBER;
 	}
@@ -175,11 +174,11 @@ static int rockchip_pcie_rd_other_conf(struct rockchip_pcie *rockchip,
 						AXI_WRAPPER_TYPE1_CFG);
 
 	if (size == 4) {
-		*val = readl(rockchip->reg_base + busdev);
+		*val = readl(addr);
 	} else if (size == 2) {
-		*val = readw(rockchip->reg_base + busdev);
+		*val = readw(addr);
 	} else if (size == 1) {
-		*val = readb(rockchip->reg_base + busdev);
+		*val = readb(addr);
 	} else {
 		*val = 0;
 		return PCIBIOS_BAD_REGISTER_NUMBER;
@@ -191,11 +190,11 @@ static int rockchip_pcie_wr_other_conf(struct rockchip_pcie *rockchip,
 				       struct pci_bus *bus, u32 devfn,
 				       int where, int size, u32 val)
 {
-	u32 busdev;
+	void __iomem *addr;
 
-	busdev = PCIE_ECAM_ADDR(bus->number, PCI_SLOT(devfn),
-				PCI_FUNC(devfn), where);
-	if (!IS_ALIGNED(busdev, size))
+	addr = rockchip->reg_base + PCIE_ECAM_OFFSET(bus->number, devfn, where);
+
+	if (!IS_ALIGNED((uintptr_t)addr, size))
 		return PCIBIOS_BAD_REGISTER_NUMBER;
 
 	if (pci_is_root_bus(bus->parent))
@@ -206,11 +205,11 @@ static int rockchip_pcie_wr_other_conf(struct rockchip_pcie *rockchip,
 						AXI_WRAPPER_TYPE1_CFG);
 
 	if (size == 4)
-		writel(val, rockchip->reg_base + busdev);
+		writel(val, addr);
 	else if (size == 2)
-		writew(val, rockchip->reg_base + busdev);
+		writew(val, addr);
 	else if (size == 1)
-		writeb(val, rockchip->reg_base + busdev);
+		writeb(val, addr);
 	else
 		return PCIBIOS_BAD_REGISTER_NUMBER;
 
diff --git a/drivers/pci/controller/pcie-rockchip.h b/drivers/pci/controller/pcie-rockchip.h
index c7d0178fc8c2..1650a5087450 100644
--- a/drivers/pci/controller/pcie-rockchip.h
+++ b/drivers/pci/controller/pcie-rockchip.h
@@ -13,6 +13,7 @@
 
 #include <linux/kernel.h>
 #include <linux/pci.h>
+#include <linux/pci-ecam.h>
 
 /*
  * The upper 16 bits of PCIE_CLIENT_CONFIG are a write mask for the lower 16
@@ -178,13 +179,6 @@
 #define MIN_AXI_ADDR_BITS_PASSED		8
 #define PCIE_RC_SEND_PME_OFF			0x11960
 #define ROCKCHIP_VENDOR_ID			0x1d87
-#define PCIE_ECAM_BUS(x)			(((x) & 0xff) << 20)
-#define PCIE_ECAM_DEV(x)			(((x) & 0x1f) << 15)
-#define PCIE_ECAM_FUNC(x)			(((x) & 0x7) << 12)
-#define PCIE_ECAM_REG(x)			(((x) & 0xfff) << 0)
-#define PCIE_ECAM_ADDR(bus, dev, func, reg) \
-	  (PCIE_ECAM_BUS(bus) | PCIE_ECAM_DEV(dev) | \
-	   PCIE_ECAM_FUNC(func) | PCIE_ECAM_REG(reg))
 #define PCIE_LINK_IS_L2(x) \
 	(((x) & PCIE_CLIENT_DEBUG_LTSSM_MASK) == PCIE_CLIENT_DEBUG_LTSSM_L2)
 #define PCIE_LINK_UP(x) \
diff --git a/drivers/pci/controller/pcie-tango.c b/drivers/pci/controller/pcie-tango.c
index d093a8ce4bb1..8f0d695afbde 100644
--- a/drivers/pci/controller/pcie-tango.c
+++ b/drivers/pci/controller/pcie-tango.c
@@ -208,7 +208,7 @@ static int smp8759_config_write(struct pci_bus *bus, unsigned int devfn,
 }
 
 static const struct pci_ecam_ops smp8759_ecam_ops = {
-	.bus_shift	= 20,
+	.bus_shift	= PCIE_ECAM_BUS_SHIFT,
 	.pci_ops	= {
 		.map_bus	= pci_ecam_map_bus,
 		.read		= smp8759_config_read,
diff --git a/drivers/pci/controller/pcie-xilinx-nwl.c b/drivers/pci/controller/pcie-xilinx-nwl.c
index f3cf7d61924f..7f29c2fdcd51 100644
--- a/drivers/pci/controller/pcie-xilinx-nwl.c
+++ b/drivers/pci/controller/pcie-xilinx-nwl.c
@@ -18,6 +18,7 @@
 #include <linux/of_platform.h>
 #include <linux/of_irq.h>
 #include <linux/pci.h>
+#include <linux/pci-ecam.h>
 #include <linux/platform_device.h>
 #include <linux/irqchip/chained_irq.h>
 
@@ -124,8 +125,6 @@
 #define E_ECAM_CR_ENABLE		BIT(0)
 #define E_ECAM_SIZE_LOC			GENMASK(20, 16)
 #define E_ECAM_SIZE_SHIFT		16
-#define ECAM_BUS_LOC_SHIFT		20
-#define ECAM_DEV_LOC_SHIFT		12
 #define NWL_ECAM_VALUE_DEFAULT		12
 
 #define CFG_DMA_REG_BAR			GENMASK(2, 0)
@@ -240,15 +239,11 @@ static void __iomem *nwl_pcie_map_bus(struct pci_bus *bus, unsigned int devfn,
 				      int where)
 {
 	struct nwl_pcie *pcie = bus->sysdata;
-	int relbus;
 
 	if (!nwl_pcie_valid_device(bus, devfn))
 		return NULL;
 
-	relbus = (bus->number << ECAM_BUS_LOC_SHIFT) |
-			(devfn << ECAM_DEV_LOC_SHIFT);
-
-	return pcie->ecam_base + relbus + where;
+	return pcie->ecam_base + PCIE_ECAM_OFFSET(bus->number, devfn, where);
 }
 
 /* PCIe operations */
diff --git a/drivers/pci/controller/pcie-xilinx.c b/drivers/pci/controller/pcie-xilinx.c
index 8523be61bba5..fa5baeb82653 100644
--- a/drivers/pci/controller/pcie-xilinx.c
+++ b/drivers/pci/controller/pcie-xilinx.c
@@ -21,6 +21,7 @@
 #include <linux/of_platform.h>
 #include <linux/of_irq.h>
 #include <linux/pci.h>
+#include <linux/pci-ecam.h>
 #include <linux/platform_device.h>
 
 #include "../pci.h"
@@ -86,10 +87,6 @@
 /* Phy Status/Control Register definitions */
 #define XILINX_PCIE_REG_PSCR_LNKUP	BIT(11)
 
-/* ECAM definitions */
-#define ECAM_BUS_NUM_SHIFT		20
-#define ECAM_DEV_NUM_SHIFT		12
-
 /* Number of MSI IRQs */
 #define XILINX_NUM_MSI_IRQS		128
 
@@ -183,15 +180,11 @@ static void __iomem *xilinx_pcie_map_bus(struct pci_bus *bus,
 					 unsigned int devfn, int where)
 {
 	struct xilinx_pcie_port *port = bus->sysdata;
-	int relbus;
 
 	if (!xilinx_pcie_valid_device(bus, devfn))
 		return NULL;
 
-	relbus = (bus->number << ECAM_BUS_NUM_SHIFT) |
-		 (devfn << ECAM_DEV_NUM_SHIFT);
-
-	return port->reg_base + relbus + where;
+	return port->reg_base + PCIE_ECAM_OFFSET(bus->number, devfn, where);
 }
 
 /* PCIe operations */
diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c
index f375c21ceeb1..59fa9a94860f 100644
--- a/drivers/pci/controller/vmd.c
+++ b/drivers/pci/controller/vmd.c
@@ -11,6 +11,7 @@
 #include <linux/module.h>
 #include <linux/msi.h>
 #include <linux/pci.h>
+#include <linux/pci-ecam.h>
 #include <linux/srcu.h>
 #include <linux/rculist.h>
 #include <linux/rcupdate.h>
@@ -94,7 +95,7 @@ struct vmd_dev {
 	struct pci_dev		*dev;
 
 	spinlock_t		cfg_lock;
-	char __iomem		*cfgbar;
+	void __iomem		*cfgbar;
 
 	int msix_count;
 	struct vmd_irq_list	*irqs;
@@ -325,18 +326,16 @@ static void vmd_remove_irq_domain(struct vmd_dev *vmd)
 	}
 }
 
-static char __iomem *vmd_cfg_addr(struct vmd_dev *vmd, struct pci_bus *bus,
+static void __iomem *vmd_cfg_addr(struct vmd_dev *vmd, struct pci_bus *bus,
 				  unsigned int devfn, int reg, int len)
 {
-	char __iomem *addr = vmd->cfgbar +
-			     ((bus->number - vmd->busn_start) << 20) +
-			     (devfn << 12) + reg;
+	unsigned int busnr_ecam = bus->number - vmd->busn_start;
+	u32 offset = PCIE_ECAM_OFFSET(busnr_ecam, devfn, reg);
 
-	if ((addr - vmd->cfgbar) + len >=
-	    resource_size(&vmd->dev->resource[VMD_CFGBAR]))
+	if (offset + len >= resource_size(&vmd->dev->resource[VMD_CFGBAR]))
 		return NULL;
 
-	return addr;
+	return vmd->cfgbar + offset;
 }
 
 /*
@@ -347,7 +346,7 @@ static int vmd_pci_read(struct pci_bus *bus, unsigned int devfn, int reg,
 			int len, u32 *value)
 {
 	struct vmd_dev *vmd = vmd_from_bus(bus);
-	char __iomem *addr = vmd_cfg_addr(vmd, bus, devfn, reg, len);
+	void __iomem *addr = vmd_cfg_addr(vmd, bus, devfn, reg, len);
 	unsigned long flags;
 	int ret = 0;
 
@@ -382,7 +381,7 @@ static int vmd_pci_write(struct pci_bus *bus, unsigned int devfn, int reg,
 			 int len, u32 value)
 {
 	struct vmd_dev *vmd = vmd_from_bus(bus);
-	char __iomem *addr = vmd_cfg_addr(vmd, bus, devfn, reg, len);
+	void __iomem *addr = vmd_cfg_addr(vmd, bus, devfn, reg, len);
 	unsigned long flags;
 	int ret = 0;
 
diff --git a/drivers/pci/ecam.c b/drivers/pci/ecam.c
index b54d32a31669..1e0229765349 100644
--- a/drivers/pci/ecam.c
+++ b/drivers/pci/ecam.c
@@ -149,7 +149,7 @@ EXPORT_SYMBOL_GPL(pci_ecam_map_bus);
 
 /* ECAM ops */
 const struct pci_ecam_ops pci_generic_ecam_ops = {
-	.bus_shift	= 20,
+	.bus_shift	= PCIE_ECAM_BUS_SHIFT,
 	.pci_ops	= {
 		.map_bus	= pci_ecam_map_bus,
 		.read		= pci_generic_config_read,
@@ -161,7 +161,7 @@ EXPORT_SYMBOL_GPL(pci_generic_ecam_ops);
 #if defined(CONFIG_ACPI) && defined(CONFIG_PCI_QUIRKS)
 /* ECAM ops for 32-bit access only (non-compliant) */
 const struct pci_ecam_ops pci_32b_ops = {
-	.bus_shift	= 20,
+	.bus_shift	= PCIE_ECAM_BUS_SHIFT,
 	.pci_ops	= {
 		.map_bus	= pci_ecam_map_bus,
 		.read		= pci_generic_config_read32,
diff --git a/include/linux/pci-ecam.h b/include/linux/pci-ecam.h
index 033ce74f02e8..9767922461ca 100644
--- a/include/linux/pci-ecam.h
+++ b/include/linux/pci-ecam.h
@@ -9,6 +9,29 @@
 #include <linux/kernel.h>
 #include <linux/platform_device.h>
 
+/*
+ * Memory address shift values for the byte-level address that
+ * can be used when accessing the PCI Express Configuration Space.
+ */
+
+/*
+ * Enhanced Configuration Access Mechanism (ECAM)
+ *
+ * See PCI Express Base Specification, Revision 5.0, Version 1.0,
+ * Section 7.2.2, Table 7-1, p. 677.
+ */
+#define PCIE_ECAM_BUS_SHIFT	20 /* Bus Number */
+#define PCIE_ECAM_DEVFN_SHIFT	12 /* Device and Function Number */
+
+#define PCIE_ECAM_BUS(x)	(((x) & 0xff) << PCIE_ECAM_BUS_SHIFT)
+#define PCIE_ECAM_DEVFN(x)	(((x) & 0xff) << PCIE_ECAM_DEVFN_SHIFT)
+#define PCIE_ECAM_REG(x)	((x) & 0xfff)
+
+#define PCIE_ECAM_OFFSET(bus, devfn, where) \
+	(PCIE_ECAM_BUS(bus) | \
+	 PCIE_ECAM_DEVFN(devfn) | \
+	 PCIE_ECAM_REG(where))
+
 /*
  * struct to hold pci ops and bus shift of the config window
  * for a PCI controller.
