Merge branch 'pci/ioremap' into next

* pci/ioremap:
  PCI: versatile: Update PCI config space remap function
  PCI: keystone-dw: Update PCI config space remap function
  PCI: layerscape: Update PCI config space remap function
  PCI: hisi: Update PCI config space remap function
  PCI: tegra: Update PCI config space remap function
  PCI: xgene: Update PCI config space remap function
  PCI: armada8k: Update PCI config space remap function
  PCI: designware: Update PCI config space remap function
  PCI: iproc-platform: Update PCI config space remap function
  PCI: qcom: Update PCI config space remap function
  PCI: rockchip: Update PCI config space remap function
  PCI: spear13xx: Update PCI config space remap function
  PCI: xilinx-nwl: Update PCI config space remap function
  PCI: xilinx: Update PCI config space remap function
  PCI: ECAM: Map config region with pci_remap_cfgspace()
  PCI: Implement devm_pci_remap_cfgspace()
  devres: fix devm_ioremap_*() offset parameter kerneldoc description
  ARM: Implement pci_remap_cfgspace() interface
  ARM64: Implement pci_remap_cfgspace() interface
  linux/io.h: Add pci_remap_cfgspace() interface
  PCI: Remove __weak tag from pci_remap_iospace()

24 files changed, 185 insertions, 31 deletions

diff --git a/Documentation/driver-model/devres.txt b/Documentation/driver-model/devres.txt
index bf34d5b3a733..e72587fe477d 100644
--- a/Documentation/driver-model/devres.txt
+++ b/Documentation/driver-model/devres.txt
@@ -342,8 +342,10 @@ PER-CPU MEM
   devm_free_percpu()
 
 PCI
-  pcim_enable_device()	: after success, all PCI ops become managed
-  pcim_pin_device()	: keep PCI device enabled after release
+  devm_pci_remap_cfgspace()	: ioremap PCI configuration space
+  devm_pci_remap_cfg_resource()	: ioremap PCI configuration space resource
+  pcim_enable_device()		: after success, all PCI ops become managed
+  pcim_pin_device()		: keep PCI device enabled after release
 
 PHY
   devm_usb_get_phy()
diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h
index 42871fb8340e..2cfbc531f63b 100644
--- a/arch/arm/include/asm/io.h
+++ b/arch/arm/include/asm/io.h
@@ -187,6 +187,16 @@ static inline void pci_ioremap_set_mem_type(int mem_type) {}
 extern int pci_ioremap_io(unsigned int offset, phys_addr_t phys_addr);
 
 /*
+ * PCI configuration space mapping function.
+ *
+ * The PCI specification does not allow configuration write
+ * transactions to be posted. Add an arch specific
+ * pci_remap_cfgspace() definition that is implemented
+ * through strongly ordered memory mappings.
+ */
+#define pci_remap_cfgspace pci_remap_cfgspace
+void __iomem *pci_remap_cfgspace(resource_size_t res_cookie, size_t size);
+/*
  * Now, pick up the machine-defined IO definitions
  */
 #ifdef CONFIG_NEED_MACH_IO_H
diff --git a/arch/arm/mm/ioremap.c b/arch/arm/mm/ioremap.c
index ff0eed23ddf1..fc91205ff46c 100644
--- a/arch/arm/mm/ioremap.c
+++ b/arch/arm/mm/ioremap.c
@@ -481,6 +481,13 @@ int pci_ioremap_io(unsigned int offset, phys_addr_t phys_addr)
 				  __pgprot(get_mem_type(pci_ioremap_mem_type)->prot_pte));
 }
 EXPORT_SYMBOL_GPL(pci_ioremap_io);
+
+void __iomem *pci_remap_cfgspace(resource_size_t res_cookie, size_t size)
+{
+	return arch_ioremap_caller(res_cookie, size, MT_UNCACHED,
+				   __builtin_return_address(0));
+}
+EXPORT_SYMBOL_GPL(pci_remap_cfgspace);
 #endif
 
 /*
diff --git a/arch/arm/mm/nommu.c b/arch/arm/mm/nommu.c
index 3b5c7aaf9c76..2a3f6002efbc 100644
--- a/arch/arm/mm/nommu.c
+++ b/arch/arm/mm/nommu.c
@@ -433,6 +433,18 @@ void __iomem *ioremap_wc(resource_size_t res_cookie, size_t size)
 }
 EXPORT_SYMBOL(ioremap_wc);
 
+#ifdef CONFIG_PCI
+
+#include <asm/mach/map.h>
+
+void __iomem *pci_remap_cfgspace(resource_size_t res_cookie, size_t size)
+{
+	return arch_ioremap_caller(res_cookie, size, MT_UNCACHED,
+				   __builtin_return_address(0));
+}
+EXPORT_SYMBOL_GPL(pci_remap_cfgspace);
+#endif
+
 void *arch_memremap_wb(phys_addr_t phys_addr, size_t size)
 {
 	return (void *)phys_addr;
diff --git a/arch/arm64/include/asm/io.h b/arch/arm64/include/asm/io.h
index 0c00c87bb9dd..35b2e50f17fb 100644
--- a/arch/arm64/include/asm/io.h
+++ b/arch/arm64/include/asm/io.h
@@ -173,6 +173,16 @@ extern void __iomem *ioremap_cache(phys_addr_t phys_addr, size_t size);
 #define iounmap				__iounmap
 
 /*
+ * PCI configuration space mapping function.
+ *
+ * The PCI specification disallows posted write configuration transactions.
+ * Add an arch specific pci_remap_cfgspace() definition that is implemented
+ * through nGnRnE device memory attribute as recommended by the ARM v8
+ * Architecture reference manual Issue A.k B2.8.2 "Device memory".
+ */
+#define pci_remap_cfgspace(addr, size) __ioremap((addr), (size), __pgprot(PROT_DEVICE_nGnRnE))
+
+/*
  * io{read,write}{16,32,64}be() macros
  */
 #define ioread16be(p)		({ __u16 __v = be16_to_cpu((__force __be16)__raw_readw(p)); __iormb(); __v; })
diff --git a/drivers/pci/dwc/pci-keystone-dw.c b/drivers/pci/dwc/pci-keystone-dw.c
index 6b396f6b4615..8bc626e640c8 100644
--- a/drivers/pci/dwc/pci-keystone-dw.c
+++ b/drivers/pci/dwc/pci-keystone-dw.c
@@ -543,7 +543,7 @@ int __init ks_dw_pcie_host_init(struct keystone_pcie *ks_pcie,
 
 	/* Index 0 is the config reg. space address */
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	pci->dbi_base = devm_ioremap_resource(dev, res);
+	pci->dbi_base = devm_pci_remap_cfg_resource(dev, res);
 	if (IS_ERR(pci->dbi_base))
 		return PTR_ERR(pci->dbi_base);
 
diff --git a/drivers/pci/dwc/pci-layerscape.c b/drivers/pci/dwc/pci-layerscape.c
index c32e392a0ae6..8f0ee0d8129c 100644
--- a/drivers/pci/dwc/pci-layerscape.c
+++ b/drivers/pci/dwc/pci-layerscape.c
@@ -283,7 +283,7 @@ static int __init ls_pcie_probe(struct platform_device *pdev)
 	pcie->pci = pci;
 
 	dbi_base = platform_get_resource_byname(pdev, IORESOURCE_MEM, "regs");
-	pci->dbi_base = devm_ioremap_resource(dev, dbi_base);
+	pci->dbi_base = devm_pci_remap_cfg_resource(dev, dbi_base);
 	if (IS_ERR(pci->dbi_base))
 		return PTR_ERR(pci->dbi_base);
 
diff --git a/drivers/pci/dwc/pcie-armada8k.c b/drivers/pci/dwc/pcie-armada8k.c
index f110e3b24a26..3ff31301323b 100644
--- a/drivers/pci/dwc/pcie-armada8k.c
+++ b/drivers/pci/dwc/pcie-armada8k.c
@@ -230,7 +230,7 @@ static int armada8k_pcie_probe(struct platform_device *pdev)
 
 	/* Get the dw-pcie unit configuration/control registers base. */
 	base = platform_get_resource_byname(pdev, IORESOURCE_MEM, "ctrl");
-	pci->dbi_base = devm_ioremap_resource(dev, base);
+	pci->dbi_base = devm_pci_remap_cfg_resource(dev, base);
 	if (IS_ERR(pci->dbi_base)) {
 		dev_err(dev, "couldn't remap regs base %p\n", base);
 		ret = PTR_ERR(pci->dbi_base);
diff --git a/drivers/pci/dwc/pcie-designware-host.c b/drivers/pci/dwc/pcie-designware-host.c
index aece2962defc..28ed32ba4f1b 100644
--- a/drivers/pci/dwc/pcie-designware-host.c
+++ b/drivers/pci/dwc/pcie-designware-host.c
@@ -339,8 +339,9 @@ int dw_pcie_host_init(struct pcie_port *pp)
 	}
 
 	if (!pci->dbi_base) {
-		pci->dbi_base = devm_ioremap(dev, pp->cfg->start,
-					resource_size(pp->cfg));
+		pci->dbi_base = devm_pci_remap_cfgspace(dev,
+						pp->cfg->start,
+						resource_size(pp->cfg));
 		if (!pci->dbi_base) {
 			dev_err(dev, "error with ioremap\n");
 			ret = -ENOMEM;
@@ -351,8 +352,8 @@ int dw_pcie_host_init(struct pcie_port *pp)
 	pp->mem_base = pp->mem->start;
 
 	if (!pp->va_cfg0_base) {
-		pp->va_cfg0_base = devm_ioremap(dev, pp->cfg0_base,
-						pp->cfg0_size);
+		pp->va_cfg0_base = devm_pci_remap_cfgspace(dev,
+					pp->cfg0_base, pp->cfg0_size);
 		if (!pp->va_cfg0_base) {
 			dev_err(dev, "error with ioremap in function\n");
 			ret = -ENOMEM;
@@ -361,7 +362,8 @@ int dw_pcie_host_init(struct pcie_port *pp)
 	}
 
 	if (!pp->va_cfg1_base) {
-		pp->va_cfg1_base = devm_ioremap(dev, pp->cfg1_base,
+		pp->va_cfg1_base = devm_pci_remap_cfgspace(dev,
+						pp->cfg1_base,
 						pp->cfg1_size);
 		if (!pp->va_cfg1_base) {
 			dev_err(dev, "error with ioremap\n");
diff --git a/drivers/pci/dwc/pcie-hisi.c b/drivers/pci/dwc/pcie-hisi.c
index fd66a3199db7..1606de5bf757 100644
--- a/drivers/pci/dwc/pcie-hisi.c
+++ b/drivers/pci/dwc/pcie-hisi.c
@@ -99,7 +99,7 @@ static int hisi_pcie_init(struct pci_config_window *cfg)
 		return -ENOMEM;
 	}
 
-	reg_base = devm_ioremap(dev, res->start, resource_size(res));
+	reg_base = devm_pci_remap_cfgspace(dev, res->start, resource_size(res));
 	if (!reg_base)
 		return -ENOMEM;
 
@@ -296,10 +296,9 @@ static int hisi_pcie_probe(struct platform_device *pdev)
 	}
 
 	reg = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rc_dbi");
-	pci->dbi_base = devm_ioremap_resource(dev, reg);
+	pci->dbi_base = devm_pci_remap_cfg_resource(dev, reg);
 	if (IS_ERR(pci->dbi_base))
 		return PTR_ERR(pci->dbi_base);
-
 	platform_set_drvdata(pdev, hisi_pcie);
 
 	ret = hisi_add_pcie_port(hisi_pcie, pdev);
@@ -360,7 +359,7 @@ static int hisi_pcie_platform_init(struct pci_config_window *cfg)
 		return -EINVAL;
 	}
 
-	reg_base = devm_ioremap(dev, res->start, resource_size(res));
+	reg_base = devm_pci_remap_cfgspace(dev, res->start, resource_size(res));
 	if (!reg_base)
 		return -ENOMEM;
 
diff --git a/drivers/pci/dwc/pcie-qcom.c b/drivers/pci/dwc/pcie-qcom.c
index 67eb7f5926dd..5bf23d432fdb 100644
--- a/drivers/pci/dwc/pcie-qcom.c
+++ b/drivers/pci/dwc/pcie-qcom.c
@@ -700,7 +700,7 @@ static int qcom_pcie_probe(struct platform_device *pdev)
 		return PTR_ERR(pcie->parf);
 
 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi");
-	pci->dbi_base = devm_ioremap_resource(dev, res);
+	pci->dbi_base = devm_pci_remap_cfg_resource(dev, res);
 	if (IS_ERR(pci->dbi_base))
 		return PTR_ERR(pci->dbi_base);
 
diff --git a/drivers/pci/dwc/pcie-spear13xx.c b/drivers/pci/dwc/pcie-spear13xx.c
index eaa4ea8e2ea4..3ae59de5c043 100644
--- a/drivers/pci/dwc/pcie-spear13xx.c
+++ b/drivers/pci/dwc/pcie-spear13xx.c
@@ -273,7 +273,7 @@ static int spear13xx_pcie_probe(struct platform_device *pdev)
 	}
 
 	dbi_base = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi");
-	pci->dbi_base = devm_ioremap_resource(dev, dbi_base);
+	pci->dbi_base = devm_pci_remap_cfg_resource(dev, dbi_base);
 	if (IS_ERR(pci->dbi_base)) {
 		dev_err(dev, "couldn't remap dbi base %p\n", dbi_base);
 		ret = PTR_ERR(pci->dbi_base);
diff --git a/drivers/pci/ecam.c b/drivers/pci/ecam.c
index 2fee61bb6559..c228a2eb7faa 100644
--- a/drivers/pci/ecam.c
+++ b/drivers/pci/ecam.c
@@ -84,12 +84,14 @@ struct pci_config_window *pci_ecam_create(struct device *dev,
 		if (!cfg->winp)
 			goto err_exit_malloc;
 		for (i = 0; i < bus_range; i++) {
-			cfg->winp[i] = ioremap(cfgres->start + i * bsz, bsz);
+			cfg->winp[i] =
+				pci_remap_cfgspace(cfgres->start + i * bsz,
+						   bsz);
 			if (!cfg->winp[i])
 				goto err_exit_iomap;
 		}
 	} else {
-		cfg->win = ioremap(cfgres->start, bus_range * bsz);
+		cfg->win = pci_remap_cfgspace(cfgres->start, bus_range * bsz);
 		if (!cfg->win)
 			goto err_exit_iomap;
 	}
diff --git a/drivers/pci/host/pci-tegra.c b/drivers/pci/host/pci-tegra.c
index ed8a93f2bfb5..2618f875a600 100644
--- a/drivers/pci/host/pci-tegra.c
+++ b/drivers/pci/host/pci-tegra.c
@@ -380,7 +380,7 @@ static struct tegra_pcie_bus *tegra_pcie_bus_alloc(struct tegra_pcie *pcie,
 						   unsigned int busnr)
 {
 	struct device *dev = pcie->dev;
-	pgprot_t prot = pgprot_device(PAGE_KERNEL);
+	pgprot_t prot = pgprot_noncached(PAGE_KERNEL);
 	phys_addr_t cs = pcie->cs->start;
 	struct tegra_pcie_bus *bus;
 	unsigned int i;
@@ -1962,7 +1962,7 @@ static int tegra_pcie_parse_dt(struct tegra_pcie *pcie)
 		rp->pcie = pcie;
 		rp->np = port;
 
-		rp->base = devm_ioremap_resource(dev, &rp->regs);
+		rp->base = devm_pci_remap_cfg_resource(dev, &rp->regs);
 		if (IS_ERR(rp->base))
 			return PTR_ERR(rp->base);
 
diff --git a/drivers/pci/host/pci-versatile.c b/drivers/pci/host/pci-versatile.c
index 5ebee7d37ff5..85e773661bc8 100644
--- a/drivers/pci/host/pci-versatile.c
+++ b/drivers/pci/host/pci-versatile.c
@@ -138,7 +138,8 @@ static int versatile_pci_probe(struct platform_device *pdev)
 		return PTR_ERR(versatile_cfg_base[0]);
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 2);
-	versatile_cfg_base[1] = devm_ioremap_resource(&pdev->dev, res);
+	versatile_cfg_base[1] = devm_pci_remap_cfg_resource(&pdev->dev,
+							    res);
 	if (IS_ERR(versatile_cfg_base[1]))
 		return PTR_ERR(versatile_cfg_base[1]);
 
diff --git a/drivers/pci/host/pci-xgene.c b/drivers/pci/host/pci-xgene.c
index 1a6108788f6f..de198980432e 100644
--- a/drivers/pci/host/pci-xgene.c
+++ b/drivers/pci/host/pci-xgene.c
@@ -248,7 +248,7 @@ static int xgene_pcie_ecam_init(struct pci_config_window *cfg, u32 ipversion)
 		dev_err(dev, "can't get CSR resource\n");
 		return ret;
 	}
-	port->csr_base = devm_ioremap_resource(dev, &csr);
+	port->csr_base = devm_pci_remap_cfg_resource(dev, &csr);
 	if (IS_ERR(port->csr_base))
 		return PTR_ERR(port->csr_base);
 
@@ -359,7 +359,7 @@ static int xgene_pcie_map_reg(struct xgene_pcie_port *port,
 	struct resource *res;
 
 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "csr");
-	port->csr_base = devm_ioremap_resource(dev, res);
+	port->csr_base = devm_pci_remap_cfg_resource(dev, res);
 	if (IS_ERR(port->csr_base))
 		return PTR_ERR(port->csr_base);
 
diff --git a/drivers/pci/host/pcie-iproc-platform.c b/drivers/pci/host/pcie-iproc-platform.c
index 8c6a327ca6cd..90d2bdd94e41 100644
--- a/drivers/pci/host/pcie-iproc-platform.c
+++ b/drivers/pci/host/pcie-iproc-platform.c
@@ -67,7 +67,8 @@ static int iproc_pcie_pltfm_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	pcie->base = devm_ioremap(dev, reg.start, resource_size(&reg));
+	pcie->base = devm_pci_remap_cfgspace(dev, reg.start,
+					     resource_size(&reg));
 	if (!pcie->base) {
 		dev_err(dev, "unable to map controller registers\n");
 		return -ENOMEM;
diff --git a/drivers/pci/host/pcie-rockchip.c b/drivers/pci/host/pcie-rockchip.c
index abc7fd76b181..0e020b6e0943 100644
--- a/drivers/pci/host/pcie-rockchip.c
+++ b/drivers/pci/host/pcie-rockchip.c
@@ -832,7 +832,7 @@ static int rockchip_pcie_parse_dt(struct rockchip_pcie *rockchip)
 	regs = platform_get_resource_byname(pdev,
 					    IORESOURCE_MEM,
 					    "axi-base");
-	rockchip->reg_base = devm_ioremap_resource(dev, regs);
+	rockchip->reg_base = devm_pci_remap_cfg_resource(dev, regs);
 	if (IS_ERR(rockchip->reg_base))
 		return PTR_ERR(rockchip->reg_base);
 
diff --git a/drivers/pci/host/pcie-xilinx-nwl.c b/drivers/pci/host/pcie-xilinx-nwl.c
index 4c3e0ab35496..4b16b26ae909 100644
--- a/drivers/pci/host/pcie-xilinx-nwl.c
+++ b/drivers/pci/host/pcie-xilinx-nwl.c
@@ -761,7 +761,7 @@ static int nwl_pcie_parse_dt(struct nwl_pcie *pcie,
 	pcie->phys_pcie_reg_base = res->start;
 
 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "cfg");
-	pcie->ecam_base = devm_ioremap_resource(dev, res);
+	pcie->ecam_base = devm_pci_remap_cfg_resource(dev, res);
 	if (IS_ERR(pcie->ecam_base))
 		return PTR_ERR(pcie->ecam_base);
 	pcie->phys_ecam_base = res->start;
diff --git a/drivers/pci/host/pcie-xilinx.c b/drivers/pci/host/pcie-xilinx.c
index 7f030f5d750b..2fe2df51f9f8 100644
--- a/drivers/pci/host/pcie-xilinx.c
+++ b/drivers/pci/host/pcie-xilinx.c
@@ -606,7 +606,7 @@ static int xilinx_pcie_parse_dt(struct xilinx_pcie_port *port)
 		return err;
 	}
 
-	port->reg_base = devm_ioremap_resource(dev, &regs);
+	port->reg_base = devm_pci_remap_cfg_resource(dev, &regs);
 	if (IS_ERR(port->reg_base))
 		return PTR_ERR(port->reg_base);
 
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index f85774b3da1e..d8b5c37cecd3 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -3363,7 +3363,7 @@ unsigned long __weak pci_address_to_pio(phys_addr_t address)
  *	Only architectures that have memory mapped IO functions defined
  *	(and the PCI_IOBASE value defined) should call this function.
  */
-int __weak pci_remap_iospace(const struct resource *res, phys_addr_t phys_addr)
+int pci_remap_iospace(const struct resource *res, phys_addr_t phys_addr)
 {
 #if defined(PCI_IOBASE) && defined(CONFIG_MMU)
 	unsigned long vaddr = (unsigned long)PCI_IOBASE + res->start;
@@ -3403,6 +3403,88 @@ void pci_unmap_iospace(struct resource *res)
 }
 EXPORT_SYMBOL(pci_unmap_iospace);
 
+/**
+ * devm_pci_remap_cfgspace - Managed pci_remap_cfgspace()
+ * @dev: Generic device to remap IO address for
+ * @offset: Resource address to map
+ * @size: Size of map
+ *
+ * Managed pci_remap_cfgspace().  Map is automatically unmapped on driver
+ * detach.
+ */
+void __iomem *devm_pci_remap_cfgspace(struct device *dev,
+				      resource_size_t offset,
+				      resource_size_t size)
+{
+	void __iomem **ptr, *addr;
+
+	ptr = devres_alloc(devm_ioremap_release, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return NULL;
+
+	addr = pci_remap_cfgspace(offset, size);
+	if (addr) {
+		*ptr = addr;
+		devres_add(dev, ptr);
+	} else
+		devres_free(ptr);
+
+	return addr;
+}
+EXPORT_SYMBOL(devm_pci_remap_cfgspace);
+
+/**
+ * devm_pci_remap_cfg_resource - check, request region and ioremap cfg resource
+ * @dev: generic device to handle the resource for
+ * @res: configuration space resource to be handled
+ *
+ * Checks that a resource is a valid memory region, requests the memory
+ * region and ioremaps with pci_remap_cfgspace() API that ensures the
+ * proper PCI configuration space memory attributes are guaranteed.
+ *
+ * All operations are managed and will be undone on driver detach.
+ *
+ * Returns a pointer to the remapped memory or an ERR_PTR() encoded error code
+ * on failure. Usage example:
+ *
+ *	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ *	base = devm_pci_remap_cfg_resource(&pdev->dev, res);
+ *	if (IS_ERR(base))
+ *		return PTR_ERR(base);
+ */
+void __iomem *devm_pci_remap_cfg_resource(struct device *dev,
+					  struct resource *res)
+{
+	resource_size_t size;
+	const char *name;
+	void __iomem *dest_ptr;
+
+	BUG_ON(!dev);
+
+	if (!res || resource_type(res) != IORESOURCE_MEM) {
+		dev_err(dev, "invalid resource\n");
+		return IOMEM_ERR_PTR(-EINVAL);
+	}
+
+	size = resource_size(res);
+	name = res->name ?: dev_name(dev);
+
+	if (!devm_request_mem_region(dev, res->start, size, name)) {
+		dev_err(dev, "can't request region for resource %pR\n", res);
+		return IOMEM_ERR_PTR(-EBUSY);
+	}
+
+	dest_ptr = devm_pci_remap_cfgspace(dev, res->start, size);
+	if (!dest_ptr) {
+		dev_err(dev, "ioremap failed for resource %pR\n", res);
+		devm_release_mem_region(dev, res->start, size);
+		dest_ptr = IOMEM_ERR_PTR(-ENOMEM);
+	}
+
+	return dest_ptr;
+}
+EXPORT_SYMBOL(devm_pci_remap_cfg_resource);
+
 static void __pci_set_master(struct pci_dev *dev, bool enable)
 {
 	u16 old_cmd, cmd;
diff --git a/include/linux/io.h b/include/linux/io.h
index 82ef36eac8a1..2195d9ea4aaa 100644
--- a/include/linux/io.h
+++ b/include/linux/io.h
@@ -90,6 +90,27 @@ void devm_memunmap(struct device *dev, void *addr);
 
 void *__devm_memremap_pages(struct device *dev, struct resource *res);
 
+#ifdef CONFIG_PCI
+/*
+ * The PCI specifications (Rev 3.0, 3.2.5 "Transaction Ordering and
+ * Posting") mandate non-posted configuration transactions. There is
+ * no ioremap API in the kernel that can guarantee non-posted write
+ * semantics across arches so provide a default implementation for
+ * mapping PCI config space that defaults to ioremap_nocache(); arches
+ * should override it if they have memory mapping implementations that
+ * guarantee non-posted writes semantics to make the memory mapping
+ * compliant with the PCI specification.
+ */
+#ifndef pci_remap_cfgspace
+#define pci_remap_cfgspace pci_remap_cfgspace
+static inline void __iomem *pci_remap_cfgspace(phys_addr_t offset,
+					       size_t size)
+{
+	return ioremap_nocache(offset, size);
+}
+#endif
+#endif
+
 /*
  * Some systems do not have legacy ISA devices.
  * /dev/port is not a valid interface on these systems.
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 7e83db5440ec..9a19a8fd4de3 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1183,6 +1183,11 @@ unsigned long pci_address_to_pio(phys_addr_t addr);
 phys_addr_t pci_pio_to_address(unsigned long pio);
 int pci_remap_iospace(const struct resource *res, phys_addr_t phys_addr);
 void pci_unmap_iospace(struct resource *res);
+void __iomem *devm_pci_remap_cfgspace(struct device *dev,
+				      resource_size_t offset,
+				      resource_size_t size);
+void __iomem *devm_pci_remap_cfg_resource(struct device *dev,
+					  struct resource *res);
 
 static inline pci_bus_addr_t pci_bus_address(struct pci_dev *pdev, int bar)
 {
diff --git a/lib/devres.c b/lib/devres.c
index cb1464c411a2..78eca713b1d9 100644
--- a/lib/devres.c
+++ b/lib/devres.c
@@ -17,7 +17,7 @@ static int devm_ioremap_match(struct device *dev, void *res, void *match_data)
 /**
  * devm_ioremap - Managed ioremap()
  * @dev: Generic device to remap IO address for
- * @offset: BUS offset to map
+ * @offset: Resource address to map
  * @size: Size of map
  *
  * Managed ioremap().  Map is automatically unmapped on driver detach.
@@ -45,7 +45,7 @@ EXPORT_SYMBOL(devm_ioremap);
 /**
  * devm_ioremap_nocache - Managed ioremap_nocache()
  * @dev: Generic device to remap IO address for
- * @offset: BUS offset to map
+ * @offset: Resource address to map
  * @size: Size of map
  *
  * Managed ioremap_nocache().  Map is automatically unmapped on driver
@@ -74,7 +74,7 @@ EXPORT_SYMBOL(devm_ioremap_nocache);
 /**
  * devm_ioremap_wc - Managed ioremap_wc()
  * @dev: Generic device to remap IO address for
- * @offset: BUS offset to map
+ * @offset: Resource address to map
  * @size: Size of map
  *
  * Managed ioremap_wc().  Map is automatically unmapped on driver detach.