Merge branch 'remotes/lorenzo/pci/controller-misc'

  - Remove redundant controller tests for "device_type == pci" (Rob
    Herring)

  - Document R-Car E3 (R8A77990) bindings (Tho Vu)

  - Add device tree support for R-Car r8a7744 (Biju Das)

  - Drop unused mvebu PCIe capability code (Thomas Petazzoni)

  - Add shared PCI bridge emulation code (Thomas Petazzoni)

  - Convert mvebu to use shared PCI bridge emulation (Thomas Petazzoni)

  - Add aardvark Root Port emulation (Thomas Petazzoni)

* remotes/lorenzo/pci/controller-misc:
  PCI: aardvark: Implement emulated root PCI bridge config space
  PCI: mvebu: Convert to PCI emulated bridge config space
  PCI: mvebu: Drop unused PCI express capability code
  PCI: Introduce PCI bridge emulated config space common logic
  dt-bindings: PCI: rcar: Add device tree support for r8a7744
  dt-bindings: PCI: rcar: Add device tree support for r8a7744
  DT: pci: rcar-pci: document R8A77990 bindings
  PCI: Remove unnecessary check of device_type == pci

12 files changed, 764 insertions, 325 deletions

diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
index deb68be4fdac..2dcc30429e8b 100644
--- a/drivers/pci/Kconfig
+++ b/drivers/pci/Kconfig
@@ -98,6 +98,9 @@ config PCI_ECAM
 config PCI_LOCKLESS_CONFIG
 	bool
 
+config PCI_BRIDGE_EMUL
+	bool
+
 config PCI_IOV
 	bool "PCI IOV support"
 	depends on PCI
diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile
index 85f4a703b2be..f2bda77a2df1 100644
--- a/drivers/pci/Makefile
+++ b/drivers/pci/Makefile
@@ -19,6 +19,7 @@ obj-$(CONFIG_HOTPLUG_PCI)	+= hotplug/
 obj-$(CONFIG_PCI_MSI)		+= msi.o
 obj-$(CONFIG_PCI_ATS)		+= ats.o
 obj-$(CONFIG_PCI_IOV)		+= iov.o
+obj-$(CONFIG_PCI_BRIDGE_EMUL)	+= pci-bridge-emul.o
 obj-$(CONFIG_ACPI)		+= pci-acpi.o
 obj-$(CONFIG_PCI_LABEL)		+= pci-label.o
 obj-$(CONFIG_X86_INTEL_MID)	+= pci-mid.o
diff --git a/drivers/pci/controller/Kconfig b/drivers/pci/controller/Kconfig
index 028b287466fb..5d76ef51532d 100644
--- a/drivers/pci/controller/Kconfig
+++ b/drivers/pci/controller/Kconfig
@@ -9,12 +9,14 @@ config PCI_MVEBU
 	depends on MVEBU_MBUS
 	depends on ARM
 	depends on OF
+	select PCI_BRIDGE_EMUL
 
 config PCI_AARDVARK
 	bool "Aardvark PCIe controller"
 	depends on (ARCH_MVEBU && ARM64) || COMPILE_TEST
 	depends on OF
 	depends on PCI_MSI_IRQ_DOMAIN
+	select PCI_BRIDGE_EMUL
 	help
 	 Add support for Aardvark 64bit PCIe Host Controller. This
 	 controller is part of the South Bridge of the Marvel Armada
diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c
index 6b4555ff2548..750081c1cb48 100644
--- a/drivers/pci/controller/pci-aardvark.c
+++ b/drivers/pci/controller/pci-aardvark.c
@@ -20,12 +20,16 @@
 #include <linux/of_pci.h>
 
 #include "../pci.h"
+#include "../pci-bridge-emul.h"
 
 /* PCIe core registers */
+#define PCIE_CORE_DEV_ID_REG					0x0
 #define PCIE_CORE_CMD_STATUS_REG				0x4
 #define     PCIE_CORE_CMD_IO_ACCESS_EN				BIT(0)
 #define     PCIE_CORE_CMD_MEM_ACCESS_EN				BIT(1)
 #define     PCIE_CORE_CMD_MEM_IO_REQ_EN				BIT(2)
+#define PCIE_CORE_DEV_REV_REG					0x8
+#define PCIE_CORE_PCIEXP_CAP					0xc0
 #define PCIE_CORE_DEV_CTRL_STATS_REG				0xc8
 #define     PCIE_CORE_DEV_CTRL_STATS_RELAX_ORDER_DISABLE	(0 << 4)
 #define     PCIE_CORE_DEV_CTRL_STATS_MAX_PAYLOAD_SZ_SHIFT	5
@@ -41,7 +45,10 @@
 #define     PCIE_CORE_ERR_CAPCTL_ECRC_CHK_TX_EN			BIT(6)
 #define     PCIE_CORE_ERR_CAPCTL_ECRC_CHCK			BIT(7)
 #define     PCIE_CORE_ERR_CAPCTL_ECRC_CHCK_RCV			BIT(8)
-
+#define     PCIE_CORE_INT_A_ASSERT_ENABLE			1
+#define     PCIE_CORE_INT_B_ASSERT_ENABLE			2
+#define     PCIE_CORE_INT_C_ASSERT_ENABLE			3
+#define     PCIE_CORE_INT_D_ASSERT_ENABLE			4
 /* PIO registers base address and register offsets */
 #define PIO_BASE_ADDR				0x4000
 #define PIO_CTRL				(PIO_BASE_ADDR + 0x0)
@@ -93,7 +100,9 @@
 #define     PCIE_CORE_CTRL2_STRICT_ORDER_ENABLE	BIT(5)
 #define     PCIE_CORE_CTRL2_OB_WIN_ENABLE	BIT(6)
 #define     PCIE_CORE_CTRL2_MSI_ENABLE		BIT(10)
+#define PCIE_MSG_LOG_REG			(CONTROL_BASE_ADDR + 0x30)
 #define PCIE_ISR0_REG				(CONTROL_BASE_ADDR + 0x40)
+#define PCIE_MSG_PM_PME_MASK			BIT(7)
 #define PCIE_ISR0_MASK_REG			(CONTROL_BASE_ADDR + 0x44)
 #define     PCIE_ISR0_MSI_INT_PENDING		BIT(24)
 #define     PCIE_ISR0_INTX_ASSERT(val)		BIT(16 + (val))
@@ -189,6 +198,7 @@ struct advk_pcie {
 	struct mutex msi_used_lock;
 	u16 msi_msg;
 	int root_bus_nr;
+	struct pci_bridge_emul bridge;
 };
 
 static inline void advk_writel(struct advk_pcie *pcie, u32 val, u64 reg)
@@ -390,6 +400,109 @@ static int advk_pcie_wait_pio(struct advk_pcie *pcie)
 	return -ETIMEDOUT;
 }
 
+
+static pci_bridge_emul_read_status_t
+advk_pci_bridge_emul_pcie_conf_read(struct pci_bridge_emul *bridge,
+				    int reg, u32 *value)
+{
+	struct advk_pcie *pcie = bridge->data;
+
+
+	switch (reg) {
+	case PCI_EXP_SLTCTL:
+		*value = PCI_EXP_SLTSTA_PDS << 16;
+		return PCI_BRIDGE_EMUL_HANDLED;
+
+	case PCI_EXP_RTCTL: {
+		u32 val = advk_readl(pcie, PCIE_ISR0_MASK_REG);
+		*value = (val & PCIE_MSG_PM_PME_MASK) ? PCI_EXP_RTCTL_PMEIE : 0;
+		return PCI_BRIDGE_EMUL_HANDLED;
+	}
+
+	case PCI_EXP_RTSTA: {
+		u32 isr0 = advk_readl(pcie, PCIE_ISR0_REG);
+		u32 msglog = advk_readl(pcie, PCIE_MSG_LOG_REG);
+		*value = (isr0 & PCIE_MSG_PM_PME_MASK) << 16 | (msglog >> 16);
+		return PCI_BRIDGE_EMUL_HANDLED;
+	}
+
+	case PCI_CAP_LIST_ID:
+	case PCI_EXP_DEVCAP:
+	case PCI_EXP_DEVCTL:
+	case PCI_EXP_LNKCAP:
+	case PCI_EXP_LNKCTL:
+		*value = advk_readl(pcie, PCIE_CORE_PCIEXP_CAP + reg);
+		return PCI_BRIDGE_EMUL_HANDLED;
+	default:
+		return PCI_BRIDGE_EMUL_NOT_HANDLED;
+	}
+
+}
+
+static void
+advk_pci_bridge_emul_pcie_conf_write(struct pci_bridge_emul *bridge,
+				     int reg, u32 old, u32 new, u32 mask)
+{
+	struct advk_pcie *pcie = bridge->data;
+
+	switch (reg) {
+	case PCI_EXP_DEVCTL:
+	case PCI_EXP_LNKCTL:
+		advk_writel(pcie, new, PCIE_CORE_PCIEXP_CAP + reg);
+		break;
+
+	case PCI_EXP_RTCTL:
+		new = (new & PCI_EXP_RTCTL_PMEIE) << 3;
+		advk_writel(pcie, new, PCIE_ISR0_MASK_REG);
+		break;
+
+	case PCI_EXP_RTSTA:
+		new = (new & PCI_EXP_RTSTA_PME) >> 9;
+		advk_writel(pcie, new, PCIE_ISR0_REG);
+		break;
+
+	default:
+		break;
+	}
+}
+
+struct pci_bridge_emul_ops advk_pci_bridge_emul_ops = {
+	.read_pcie = advk_pci_bridge_emul_pcie_conf_read,
+	.write_pcie = advk_pci_bridge_emul_pcie_conf_write,
+};
+
+/*
+ * Initialize the configuration space of the PCI-to-PCI bridge
+ * associated with the given PCIe interface.
+ */
+static void advk_sw_pci_bridge_init(struct advk_pcie *pcie)
+{
+	struct pci_bridge_emul *bridge = &pcie->bridge;
+
+	bridge->conf.vendor = advk_readl(pcie, PCIE_CORE_DEV_ID_REG) & 0xffff;
+	bridge->conf.device = advk_readl(pcie, PCIE_CORE_DEV_ID_REG) >> 16;
+	bridge->conf.class_revision =
+		advk_readl(pcie, PCIE_CORE_DEV_REV_REG) & 0xff;
+
+	/* Support 32 bits I/O addressing */
+	bridge->conf.iobase = PCI_IO_RANGE_TYPE_32;
+	bridge->conf.iolimit = PCI_IO_RANGE_TYPE_32;
+
+	/* Support 64 bits memory pref */
+	bridge->conf.pref_mem_base = PCI_PREF_RANGE_TYPE_64;
+	bridge->conf.pref_mem_limit = PCI_PREF_RANGE_TYPE_64;
+
+	/* Support interrupt A for MSI feature */
+	bridge->conf.intpin = PCIE_CORE_INT_A_ASSERT_ENABLE;
+
+	bridge->has_pcie = true;
+	bridge->data = pcie;
+	bridge->ops = &advk_pci_bridge_emul_ops;
+
+	pci_bridge_emul_init(bridge);
+
+}
+
 static bool advk_pcie_valid_device(struct advk_pcie *pcie, struct pci_bus *bus,
 				  int devfn)
 {
@@ -411,6 +524,10 @@ static int advk_pcie_rd_conf(struct pci_bus *bus, u32 devfn,
 		return PCIBIOS_DEVICE_NOT_FOUND;
 	}
 
+	if (bus->number == pcie->root_bus_nr)
+		return pci_bridge_emul_conf_read(&pcie->bridge, where,
+						 size, val);
+
 	/* Start PIO */
 	advk_writel(pcie, 0, PIO_START);
 	advk_writel(pcie, 1, PIO_ISR);
@@ -418,7 +535,7 @@ static int advk_pcie_rd_conf(struct pci_bus *bus, u32 devfn,
 	/* Program the control register */
 	reg = advk_readl(pcie, PIO_CTRL);
 	reg &= ~PIO_CTRL_TYPE_MASK;
-	if (bus->number ==  pcie->root_bus_nr)
+	if (bus->primary ==  pcie->root_bus_nr)
 		reg |= PCIE_CONFIG_RD_TYPE0;
 	else
 		reg |= PCIE_CONFIG_RD_TYPE1;
@@ -463,6 +580,10 @@ static int advk_pcie_wr_conf(struct pci_bus *bus, u32 devfn,
 	if (!advk_pcie_valid_device(pcie, bus, devfn))
 		return PCIBIOS_DEVICE_NOT_FOUND;
 
+	if (bus->number == pcie->root_bus_nr)
+		return pci_bridge_emul_conf_write(&pcie->bridge, where,
+						  size, val);
+
 	if (where % size)
 		return PCIBIOS_SET_FAILED;
 
@@ -473,7 +594,7 @@ static int advk_pcie_wr_conf(struct pci_bus *bus, u32 devfn,
 	/* Program the control register */
 	reg = advk_readl(pcie, PIO_CTRL);
 	reg &= ~PIO_CTRL_TYPE_MASK;
-	if (bus->number == pcie->root_bus_nr)
+	if (bus->primary == pcie->root_bus_nr)
 		reg |= PCIE_CONFIG_WR_TYPE0;
 	else
 		reg |= PCIE_CONFIG_WR_TYPE1;
@@ -875,6 +996,8 @@ static int advk_pcie_probe(struct platform_device *pdev)
 
 	advk_pcie_setup_hw(pcie);
 
+	advk_sw_pci_bridge_init(pcie);
+
 	ret = advk_pcie_init_irq_domain(pcie);
 	if (ret) {
 		dev_err(dev, "Failed to initialize irq\n");
diff --git a/drivers/pci/controller/pci-host-common.c b/drivers/pci/controller/pci-host-common.c
index d8f10451f273..c742881b5061 100644
--- a/drivers/pci/controller/pci-host-common.c
+++ b/drivers/pci/controller/pci-host-common.c
@@ -58,9 +58,7 @@ err_out:
 int pci_host_common_probe(struct platform_device *pdev,
 			  struct pci_ecam_ops *ops)
 {
-	const char *type;
 	struct device *dev = &pdev->dev;
-	struct device_node *np = dev->of_node;
 	struct pci_host_bridge *bridge;
 	struct pci_config_window *cfg;
 	struct list_head resources;
@@ -70,12 +68,6 @@ int pci_host_common_probe(struct platform_device *pdev,
 	if (!bridge)
 		return -ENOMEM;
 
-	type = of_get_property(np, "device_type", NULL);
-	if (!type || strcmp(type, "pci")) {
-		dev_err(dev, "invalid \"device_type\" %s\n", type);
-		return -EINVAL;
-	}
-
 	of_pci_check_probe_only();
 
 	/* Parse and map our Configuration Space windows */
diff --git a/drivers/pci/controller/pci-mvebu.c b/drivers/pci/controller/pci-mvebu.c
index 50eb0729385b..4711ca8fa5d4 100644
--- a/drivers/pci/controller/pci-mvebu.c
+++ b/drivers/pci/controller/pci-mvebu.c
@@ -22,6 +22,7 @@
 #include <linux/of_platform.h>
 
 #include "../pci.h"
+#include "../pci-bridge-emul.h"
 
 /*
  * PCIe unit register offsets.
@@ -63,61 +64,6 @@
 #define PCIE_DEBUG_CTRL         0x1a60
 #define  PCIE_DEBUG_SOFT_RESET		BIT(20)
 
-enum {
-	PCISWCAP = PCI_BRIDGE_CONTROL + 2,
-	PCISWCAP_EXP_LIST_ID	= PCISWCAP + PCI_CAP_LIST_ID,
-	PCISWCAP_EXP_DEVCAP	= PCISWCAP + PCI_EXP_DEVCAP,
-	PCISWCAP_EXP_DEVCTL	= PCISWCAP + PCI_EXP_DEVCTL,
-	PCISWCAP_EXP_LNKCAP	= PCISWCAP + PCI_EXP_LNKCAP,
-	PCISWCAP_EXP_LNKCTL	= PCISWCAP + PCI_EXP_LNKCTL,
-	PCISWCAP_EXP_SLTCAP	= PCISWCAP + PCI_EXP_SLTCAP,
-	PCISWCAP_EXP_SLTCTL	= PCISWCAP + PCI_EXP_SLTCTL,
-	PCISWCAP_EXP_RTCTL	= PCISWCAP + PCI_EXP_RTCTL,
-	PCISWCAP_EXP_RTSTA	= PCISWCAP + PCI_EXP_RTSTA,
-	PCISWCAP_EXP_DEVCAP2	= PCISWCAP + PCI_EXP_DEVCAP2,
-	PCISWCAP_EXP_DEVCTL2	= PCISWCAP + PCI_EXP_DEVCTL2,
-	PCISWCAP_EXP_LNKCAP2	= PCISWCAP + PCI_EXP_LNKCAP2,
-	PCISWCAP_EXP_LNKCTL2	= PCISWCAP + PCI_EXP_LNKCTL2,
-	PCISWCAP_EXP_SLTCAP2	= PCISWCAP + PCI_EXP_SLTCAP2,
-	PCISWCAP_EXP_SLTCTL2	= PCISWCAP + PCI_EXP_SLTCTL2,
-};
-
-/* PCI configuration space of a PCI-to-PCI bridge */
-struct mvebu_sw_pci_bridge {
-	u16 vendor;
-	u16 device;
-	u16 command;
-	u16 status;
-	u16 class;
-	u8 interface;
-	u8 revision;
-	u8 bist;
-	u8 header_type;
-	u8 latency_timer;
-	u8 cache_line_size;
-	u32 bar[2];
-	u8 primary_bus;
-	u8 secondary_bus;
-	u8 subordinate_bus;
-	u8 secondary_latency_timer;
-	u8 iobase;
-	u8 iolimit;
-	u16 secondary_status;
-	u16 membase;
-	u16 memlimit;
-	u16 iobaseupper;
-	u16 iolimitupper;
-	u32 romaddr;
-	u8 intline;
-	u8 intpin;
-	u16 bridgectrl;
-
-	/* PCI express capability */
-	u32 pcie_sltcap;
-	u16 pcie_devctl;
-	u16 pcie_rtctl;
-};
-
 struct mvebu_pcie_port;
 
 /* Structure representing all PCIe interfaces */
@@ -153,7 +99,7 @@ struct mvebu_pcie_port {
 	struct clk *clk;
 	struct gpio_desc *reset_gpio;
 	char *reset_name;
-	struct mvebu_sw_pci_bridge bridge;
+	struct pci_bridge_emul bridge;
 	struct device_node *dn;
 	struct mvebu_pcie *pcie;
 	struct mvebu_pcie_window memwin;
@@ -415,11 +361,12 @@ static void mvebu_pcie_set_window(struct mvebu_pcie_port *port,
 static void mvebu_pcie_handle_iobase_change(struct mvebu_pcie_port *port)
 {
 	struct mvebu_pcie_window desired = {};
+	struct pci_bridge_emul_conf *conf = &port->bridge.conf;
 
 	/* Are the new iobase/iolimit values invalid? */
-	if (port->bridge.iolimit < port->bridge.iobase ||
-	    port->bridge.iolimitupper < port->bridge.iobaseupper ||
-	    !(port->bridge.command & PCI_COMMAND_IO)) {
+	if (conf->iolimit < conf->iobase ||
+	    conf->iolimitupper < conf->iobaseupper ||
+	    !(conf->command & PCI_COMMAND_IO)) {
 		mvebu_pcie_set_window(port, port->io_target, port->io_attr,
 				      &desired, &port->iowin);
 		return;
@@ -438,11 +385,11 @@ static void mvebu_pcie_handle_iobase_change(struct mvebu_pcie_port *port)
 	 * specifications. iobase is the bus address, port->iowin_base
 	 * is the CPU address.
 	 */
-	desired.remap = ((port->bridge.iobase & 0xF0) << 8) |
-			(port->bridge.iobaseupper << 16);
+	desired.remap = ((conf->iobase & 0xF0) << 8) |
+			(conf->iobaseupper << 16);
 	desired.base = port->pcie->io.start + desired.remap;
-	desired.size = ((0xFFF | ((port->bridge.iolimit & 0xF0) << 8) |
-			 (port->bridge.iolimitupper << 16)) -
+	desired.size = ((0xFFF | ((conf->iolimit & 0xF0) << 8) |
+			 (conf->iolimitupper << 16)) -
 			desired.remap) +
 		       1;
 
@@ -453,10 +400,11 @@ static void mvebu_pcie_handle_iobase_change(struct mvebu_pcie_port *port)
 static void mvebu_pcie_handle_membase_change(struct mvebu_pcie_port *port)
 {
 	struct mvebu_pcie_window desired = {.remap = MVEBU_MBUS_NO_REMAP};
+	struct pci_bridge_emul_conf *conf = &port->bridge.conf;
 
 	/* Are the new membase/memlimit values invalid? */
-	if (port->bridge.memlimit < port->bridge.membase ||
-	    !(port->bridge.command & PCI_COMMAND_MEMORY)) {
+	if (conf->memlimit < conf->membase ||
+	    !(conf->command & PCI_COMMAND_MEMORY)) {
 		mvebu_pcie_set_window(port, port->mem_target, port->mem_attr,
 				      &desired, &port->memwin);
 		return;
@@ -468,130 +416,32 @@ static void mvebu_pcie_handle_membase_change(struct mvebu_pcie_port *port)
 	 * window to setup, according to the PCI-to-PCI bridge
 	 * specifications.
 	 */
-	desired.base = ((port->bridge.membase & 0xFFF0) << 16);
-	desired.size = (((port->bridge.memlimit & 0xFFF0) << 16) | 0xFFFFF) -
+	desired.base = ((conf->membase & 0xFFF0) << 16);
+	desired.size = (((conf->memlimit & 0xFFF0) << 16) | 0xFFFFF) -
 		       desired.base + 1;
 
 	mvebu_pcie_set_window(port, port->mem_target, port->mem_attr, &desired,
 			      &port->memwin);
 }
 
-/*
- * Initialize the configuration space of the PCI-to-PCI bridge
- * associated with the given PCIe interface.
- */
-static void mvebu_sw_pci_bridge_init(struct mvebu_pcie_port *port)
-{
-	struct mvebu_sw_pci_bridge *bridge = &port->bridge;
-
-	memset(bridge, 0, sizeof(struct mvebu_sw_pci_bridge));
-
-	bridge->class = PCI_CLASS_BRIDGE_PCI;
-	bridge->vendor = PCI_VENDOR_ID_MARVELL;
-	bridge->device = mvebu_readl(port, PCIE_DEV_ID_OFF) >> 16;
-	bridge->revision = mvebu_readl(port, PCIE_DEV_REV_OFF) & 0xff;
-	bridge->header_type = PCI_HEADER_TYPE_BRIDGE;
-	bridge->cache_line_size = 0x10;
-
-	/* We support 32 bits I/O addressing */
-	bridge->iobase = PCI_IO_RANGE_TYPE_32;
-	bridge->iolimit = PCI_IO_RANGE_TYPE_32;
-
-	/* Add capabilities */
-	bridge->status = PCI_STATUS_CAP_LIST;
-}
-
-/*
- * Read the configuration space of the PCI-to-PCI bridge associated to
- * the given PCIe interface.
- */
-static int mvebu_sw_pci_bridge_read(struct mvebu_pcie_port *port,
-				  unsigned int where, int size, u32 *value)
+static pci_bridge_emul_read_status_t
+mvebu_pci_bridge_emul_pcie_conf_read(struct pci_bridge_emul *bridge,
+				     int reg, u32 *value)
 {
-	struct mvebu_sw_pci_bridge *bridge = &port->bridge;
-
-	switch (where & ~3) {
-	case PCI_VENDOR_ID:
-		*value = bridge->device << 16 | bridge->vendor;
-		break;
-
-	case PCI_COMMAND:
-		*value = bridge->command | bridge->status << 16;
-		break;
-
-	case PCI_CLASS_REVISION:
-		*value = bridge->class << 16 | bridge->interface << 8 |
-			 bridge->revision;
-		break;
-
-	case PCI_CACHE_LINE_SIZE:
-		*value = bridge->bist << 24 | bridge->header_type << 16 |
-			 bridge->latency_timer << 8 | bridge->cache_line_size;
-		break;
-
-	case PCI_BASE_ADDRESS_0 ... PCI_BASE_ADDRESS_1:
-		*value = bridge->bar[((where & ~3) - PCI_BASE_ADDRESS_0) / 4];
-		break;
-
-	case PCI_PRIMARY_BUS:
-		*value = (bridge->secondary_latency_timer << 24 |
-			  bridge->subordinate_bus         << 16 |
-			  bridge->secondary_bus           <<  8 |
-			  bridge->primary_bus);
-		break;
-
-	case PCI_IO_BASE:
-		if (!mvebu_has_ioport(port))
-			*value = bridge->secondary_status << 16;
-		else
-			*value = (bridge->secondary_status << 16 |
-				  bridge->iolimit          <<  8 |
-				  bridge->iobase);
-		break;
-
-	case PCI_MEMORY_BASE:
-		*value = (bridge->memlimit << 16 | bridge->membase);
-		break;
-
-	case PCI_PREF_MEMORY_BASE:
-		*value = 0;
-		break;
-
-	case PCI_IO_BASE_UPPER16:
-		*value = (bridge->iolimitupper << 16 | bridge->iobaseupper);
-		break;
-
-	case PCI_CAPABILITY_LIST:
-		*value = PCISWCAP;
-		break;
-
-	case PCI_ROM_ADDRESS1:
-		*value = 0;
-		break;
+	struct mvebu_pcie_port *port = bridge->data;
 
-	case PCI_INTERRUPT_LINE:
-		/* LINE PIN MIN_GNT MAX_LAT */
-		*value = 0;
-		break;
-
-	case PCISWCAP_EXP_LIST_ID:
-		/* Set PCIe v2, root port, slot support */
-		*value = (PCI_EXP_TYPE_ROOT_PORT << 4 | 2 |
-			  PCI_EXP_FLAGS_SLOT) << 16 | PCI_CAP_ID_EXP;
-		break;
-
-	case PCISWCAP_EXP_DEVCAP:
+	switch (reg) {
+	case PCI_EXP_DEVCAP:
 		*value = mvebu_readl(port, PCIE_CAP_PCIEXP + PCI_EXP_DEVCAP);
 		break;
 
-	case PCISWCAP_EXP_DEVCTL:
+	case PCI_EXP_DEVCTL:
 		*value = mvebu_readl(port, PCIE_CAP_PCIEXP + PCI_EXP_DEVCTL) &
 				 ~(PCI_EXP_DEVCTL_URRE | PCI_EXP_DEVCTL_FERE |
 				   PCI_EXP_DEVCTL_NFERE | PCI_EXP_DEVCTL_CERE);
-		*value |= bridge->pcie_devctl;
 		break;
 
-	case PCISWCAP_EXP_LNKCAP:
+	case PCI_EXP_LNKCAP:
 		/*
 		 * PCIe requires the clock power management capability to be
 		 * hard-wired to zero for downstream ports
@@ -600,176 +450,140 @@ static int mvebu_sw_pci_bridge_read(struct mvebu_pcie_port *port,
 			 ~PCI_EXP_LNKCAP_CLKPM;
 		break;
 
-	case PCISWCAP_EXP_LNKCTL:
+	case PCI_EXP_LNKCTL:
 		*value = mvebu_readl(port, PCIE_CAP_PCIEXP + PCI_EXP_LNKCTL);
 		break;
 
-	case PCISWCAP_EXP_SLTCAP:
-		*value = bridge->pcie_sltcap;
-		break;
-
-	case PCISWCAP_EXP_SLTCTL:
+	case PCI_EXP_SLTCTL:
 		*value = PCI_EXP_SLTSTA_PDS << 16;
 		break;
 
-	case PCISWCAP_EXP_RTCTL:
-		*value = bridge->pcie_rtctl;
-		break;
-
-	case PCISWCAP_EXP_RTSTA:
+	case PCI_EXP_RTSTA:
 		*value = mvebu_readl(port, PCIE_RC_RTSTA);
 		break;
 
-	/* PCIe requires the v2 fields to be hard-wired to zero */
-	case PCISWCAP_EXP_DEVCAP2:
-	case PCISWCAP_EXP_DEVCTL2:
-	case PCISWCAP_EXP_LNKCAP2:
-	case PCISWCAP_EXP_LNKCTL2:
-	case PCISWCAP_EXP_SLTCAP2:
-	case PCISWCAP_EXP_SLTCTL2:
 	default:
-		/*
-		 * PCI defines configuration read accesses to reserved or
-		 * unimplemented registers to read as zero and complete
-		 * normally.
-		 */
-		*value = 0;
-		return PCIBIOS_SUCCESSFUL;
+		return PCI_BRIDGE_EMUL_NOT_HANDLED;
 	}
 
-	if (size == 2)
-		*value = (*value >> (8 * (where & 3))) & 0xffff;
-	else if (size == 1)
-		*value = (*value >> (8 * (where & 3))) & 0xff;
-
-	return PCIBIOS_SUCCESSFUL;
+	return PCI_BRIDGE_EMUL_HANDLED;
 }
 
-/* Write to the PCI-to-PCI bridge configuration space */
-static int mvebu_sw_pci_bridge_write(struct mvebu_pcie_port *port,
-				     unsigned int where, int size, u32 value)
+static void
+mvebu_pci_bridge_emul_base_conf_write(struct pci_bridge_emul *bridge,
+				      int reg, u32 old, u32 new, u32 mask)
 {
-	struct mvebu_sw_pci_bridge *bridge = &port->bridge;
-	u32 mask, reg;
-	int err;
-
-	if (size == 4)
-		mask = 0x0;
-	else if (size == 2)
-		mask = ~(0xffff << ((where & 3) * 8));
-	else if (size == 1)
-		mask = ~(0xff << ((where & 3) * 8));
-	else
-		return PCIBIOS_BAD_REGISTER_NUMBER;
-
-	err = mvebu_sw_pci_bridge_read(port, where & ~3, 4, &reg);
-	if (err)
-		return err;
+	struct mvebu_pcie_port *port = bridge->data;
+	struct pci_bridge_emul_conf *conf = &bridge->conf;
 
-	value = (reg & mask) | value << ((where & 3) * 8);
-
-	switch (where & ~3) {
+	switch (reg) {
 	case PCI_COMMAND:
 	{
-		u32 old = bridge->command;
-
 		if (!mvebu_has_ioport(port))
-			value &= ~PCI_COMMAND_IO;
+			conf->command &= ~PCI_COMMAND_IO;
 
-		bridge->command = value & 0xffff;
-		if ((old ^ bridge->command) & PCI_COMMAND_IO)
+		if ((old ^ new) & PCI_COMMAND_IO)
 			mvebu_pcie_handle_iobase_change(port);
-		if ((old ^ bridge->command) & PCI_COMMAND_MEMORY)
+		if ((old ^ new) & PCI_COMMAND_MEMORY)
 			mvebu_pcie_handle_membase_change(port);
-		break;
-	}
 
-	case PCI_BASE_ADDRESS_0 ... PCI_BASE_ADDRESS_1:
-		bridge->bar[((where & ~3) - PCI_BASE_ADDRESS_0) / 4] = value;
 		break;
+	}
 
 	case PCI_IO_BASE:
 		/*
-		 * We also keep bit 1 set, it is a read-only bit that
+		 * We keep bit 1 set, it is a read-only bit that
 		 * indicates we support 32 bits addressing for the
 		 * I/O
 		 */
-		bridge->iobase = (value & 0xff) | PCI_IO_RANGE_TYPE_32;
-		bridge->iolimit = ((value >> 8) & 0xff) | PCI_IO_RANGE_TYPE_32;
+		conf->iobase |= PCI_IO_RANGE_TYPE_32;
+		conf->iolimit |= PCI_IO_RANGE_TYPE_32;
 		mvebu_pcie_handle_iobase_change(port);
 		break;
 
 	case PCI_MEMORY_BASE:
-		bridge->membase = value & 0xffff;
-		bridge->memlimit = value >> 16;
 		mvebu_pcie_handle_membase_change(port);
 		break;
 
 	case PCI_IO_BASE_UPPER16:
-		bridge->iobaseupper = value & 0xffff;
-		bridge->iolimitupper = value >> 16;
 		mvebu_pcie_handle_iobase_change(port);
 		break;
 
 	case PCI_PRIMARY_BUS:
-		bridge->primary_bus             = value & 0xff;
-		bridge->secondary_bus           = (value >> 8) & 0xff;
-		bridge->subordinate_bus         = (value >> 16) & 0xff;
-		bridge->secondary_latency_timer = (value >> 24) & 0xff;
-		mvebu_pcie_set_local_bus_nr(port, bridge->secondary_bus);
+		mvebu_pcie_set_local_bus_nr(port, conf->secondary_bus);
+		break;
+
+	default:
 		break;
+	}
+}
+
+static void
+mvebu_pci_bridge_emul_pcie_conf_write(struct pci_bridge_emul *bridge,
+				      int reg, u32 old, u32 new, u32 mask)
+{
+	struct mvebu_pcie_port *port = bridge->data;
 
-	case PCISWCAP_EXP_DEVCTL:
+	switch (reg) {
+	case PCI_EXP_DEVCTL:
 		/*
 		 * Armada370 data says these bits must always
 		 * be zero when in root complex mode.
 		 */
-		value &= ~(PCI_EXP_DEVCTL_URRE | PCI_EXP_DEVCTL_FERE |
-			   PCI_EXP_DEVCTL_NFERE | PCI_EXP_DEVCTL_CERE);
-
-		/*
-		 * If the mask is 0xffff0000, then we only want to write
-		 * the device control register, rather than clearing the
-		 * RW1C bits in the device status register.  Mask out the
-		 * status register bits.
-		 */
-		if (mask == 0xffff0000)
-			value &= 0xffff;
+		new &= ~(PCI_EXP_DEVCTL_URRE | PCI_EXP_DEVCTL_FERE |
+			 PCI_EXP_DEVCTL_NFERE | PCI_EXP_DEVCTL_CERE);
 
-		mvebu_writel(port, value, PCIE_CAP_PCIEXP + PCI_EXP_DEVCTL);
+		mvebu_writel(port, new, PCIE_CAP_PCIEXP + PCI_EXP_DEVCTL);
 		break;
 
-	case PCISWCAP_EXP_LNKCTL:
+	case PCI_EXP_LNKCTL:
 		/*
 		 * If we don't support CLKREQ, we must ensure that the
 		 * CLKREQ enable bit always reads zero.  Since we haven't
 		 * had this capability, and it's dependent on board wiring,
 		 * disable it for the time being.
 		 */
-		value &= ~PCI_EXP_LNKCTL_CLKREQ_EN;
+		new &= ~PCI_EXP_LNKCTL_CLKREQ_EN;
 
-		/*
-		 * If the mask is 0xffff0000, then we only want to write
-		 * the link control register, rather than clearing the
-		 * RW1C bits in the link status register.  Mask out the
-		 * RW1C status register bits.
-		 */
-		if (mask == 0xffff0000)
-			value &= ~((PCI_EXP_LNKSTA_LABS |
-				    PCI_EXP_LNKSTA_LBMS) << 16);
-
-		mvebu_writel(port, value, PCIE_CAP_PCIEXP + PCI_EXP_LNKCTL);
+		mvebu_writel(port, new, PCIE_CAP_PCIEXP + PCI_EXP_LNKCTL);
 		break;
 
-	case PCISWCAP_EXP_RTSTA:
-		mvebu_writel(port, value, PCIE_RC_RTSTA);
+	case PCI_EXP_RTSTA:
+		mvebu_writel(port, new, PCIE_RC_RTSTA);
 		break;
+	}
+}
 
-	default:
-		break;
+struct pci_bridge_emul_ops mvebu_pci_bridge_emul_ops = {
+	.write_base = mvebu_pci_bridge_emul_base_conf_write,
+	.read_pcie = mvebu_pci_bridge_emul_pcie_conf_read,
+	.write_pcie = mvebu_pci_bridge_emul_pcie_conf_write,
+};
+
+/*
+ * Initialize the configuration space of the PCI-to-PCI bridge
+ * associated with the given PCIe interface.
+ */
+static void mvebu_pci_bridge_emul_init(struct mvebu_pcie_port *port)
+{
+	struct pci_bridge_emul *bridge = &port->bridge;
+
+	bridge->conf.vendor = PCI_VENDOR_ID_MARVELL;
+	bridge->conf.device = mvebu_readl(port, PCIE_DEV_ID_OFF) >> 16;
+	bridge->conf.class_revision =
+		mvebu_readl(port, PCIE_DEV_REV_OFF) & 0xff;
+
+	if (mvebu_has_ioport(port)) {
+		/* We support 32 bits I/O addressing */
+		bridge->conf.iobase = PCI_IO_RANGE_TYPE_32;
+		bridge->conf.iolimit = PCI_IO_RANGE_TYPE_32;
 	}
 
-	return PCIBIOS_SUCCESSFUL;
+	bridge->has_pcie = true;
+	bridge->data = port;
+	bridge->ops = &mvebu_pci_bridge_emul_ops;
+
+	pci_bridge_emul_init(bridge);
 }
 
 static inline struct mvebu_pcie *sys_to_pcie(struct pci_sys_data *sys)
@@ -789,8 +603,8 @@ static struct mvebu_pcie_port *mvebu_pcie_find_port(struct mvebu_pcie *pcie,
 		if (bus->number == 0 && port->devfn == devfn)
 			return port;
 		if (bus->number != 0 &&
-		    bus->number >= port->bridge.secondary_bus &&
-		    bus->number <= port->bridge.subordinate_bus)
+		    bus->number >= port->bridge.conf.secondary_bus &&
+		    bus->number <= port->bridge.conf.subordinate_bus)
 			return port;
 	}
 
@@ -811,7 +625,8 @@ static int mvebu_pcie_wr_conf(struct pci_bus *bus, u32 devfn,
 
 	/* Access the emulated PCI-to-PCI bridge */
 	if (bus->number == 0)
-		return mvebu_sw_pci_bridge_write(port, where, size, val);
+		return pci_bridge_emul_conf_write(&port->bridge, where,
+						  size, val);
 
 	if (!mvebu_pcie_link_up(port))
 		return PCIBIOS_DEVICE_NOT_FOUND;
@@ -839,7 +654,8 @@ static int mvebu_pcie_rd_conf(struct pci_bus *bus, u32 devfn, int where,
 
 	/* Access the emulated PCI-to-PCI bridge */
 	if (bus->number == 0)
-		return mvebu_sw_pci_bridge_read(port, where, size, val);
+		return pci_bridge_emul_conf_read(&port->bridge, where,
+						 size, val);
 
 	if (!mvebu_pcie_link_up(port)) {
 		*val = 0xffffffff;
@@ -1253,7 +1069,7 @@ static int mvebu_pcie_probe(struct platform_device *pdev)
 
 		mvebu_pcie_setup_hw(port);
 		mvebu_pcie_set_local_dev_nr(port, 1);
-		mvebu_sw_pci_bridge_init(port);
+		mvebu_pci_bridge_emul_init(port);
 	}
 
 	pcie->nports = i;
diff --git a/drivers/pci/controller/pcie-cadence-host.c b/drivers/pci/controller/pcie-cadence-host.c
index ec394f6a19c8..97e251090b4f 100644
--- a/drivers/pci/controller/pcie-cadence-host.c
+++ b/drivers/pci/controller/pcie-cadence-host.c
@@ -235,7 +235,6 @@ static int cdns_pcie_host_init(struct device *dev,
 
 static int cdns_pcie_host_probe(struct platform_device *pdev)
 {
-	const char *type;
 	struct device *dev = &pdev->dev;
 	struct device_node *np = dev->of_node;
 	struct pci_host_bridge *bridge;
@@ -268,12 +267,6 @@ static int cdns_pcie_host_probe(struct platform_device *pdev)
 	rc->device_id = 0xffff;
 	of_property_read_u16(np, "device-id", &rc->device_id);
 
-	type = of_get_property(np, "device_type", NULL);
-	if (!type || strcmp(type, "pci")) {
-		dev_err(dev, "invalid \"device_type\" %s\n", type);
-		return -EINVAL;
-	}
-
 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "reg");
 	pcie->reg_base = devm_ioremap_resource(dev, res);
 	if (IS_ERR(pcie->reg_base)) {
diff --git a/drivers/pci/controller/pcie-mobiveil.c b/drivers/pci/controller/pcie-mobiveil.c
index a939e8d31735..77052a0712d0 100644
--- a/drivers/pci/controller/pcie-mobiveil.c
+++ b/drivers/pci/controller/pcie-mobiveil.c
@@ -301,13 +301,6 @@ static int mobiveil_pcie_parse_dt(struct mobiveil_pcie *pcie)
 	struct platform_device *pdev = pcie->pdev;
 	struct device_node *node = dev->of_node;
 	struct resource *res;
-	const char *type;
-
-	type = of_get_property(node, "device_type", NULL);
-	if (!type || strcmp(type, "pci")) {
-		dev_err(dev, "invalid \"device_type\" %s\n", type);
-		return -EINVAL;
-	}
 
 	/* map config resource */
 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
diff --git a/drivers/pci/controller/pcie-xilinx-nwl.c b/drivers/pci/controller/pcie-xilinx-nwl.c
index fb32840ce8e6..81538d77f790 100644
--- a/drivers/pci/controller/pcie-xilinx-nwl.c
+++ b/drivers/pci/controller/pcie-xilinx-nwl.c
@@ -777,16 +777,7 @@ static int nwl_pcie_parse_dt(struct nwl_pcie *pcie,
 			     struct platform_device *pdev)
 {
 	struct device *dev = pcie->dev;
-	struct device_node *node = dev->of_node;
 	struct resource *res;
-	const char *type;
-
-	/* Check for device type */
-	type = of_get_property(node, "device_type", NULL);
-	if (!type || strcmp(type, "pci")) {
-		dev_err(dev, "invalid \"device_type\" %s\n", type);
-		return -EINVAL;
-	}
 
 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "breg");
 	pcie->breg_base = devm_ioremap_resource(dev, res);
diff --git a/drivers/pci/controller/pcie-xilinx.c b/drivers/pci/controller/pcie-xilinx.c
index 7b1389d8e2a5..9bd1a35cd5d8 100644
--- a/drivers/pci/controller/pcie-xilinx.c
+++ b/drivers/pci/controller/pcie-xilinx.c
@@ -574,15 +574,8 @@ static int xilinx_pcie_parse_dt(struct xilinx_pcie_port *port)
 	struct device *dev = port->dev;
 	struct device_node *node = dev->of_node;
 	struct resource regs;
-	const char *type;
 	int err;
 
-	type = of_get_property(node, "device_type", NULL);
-	if (!type || strcmp(type, "pci")) {
-		dev_err(dev, "invalid \"device_type\" %s\n", type);
-		return -EINVAL;
-	}
-
 	err = of_address_to_resource(node, 0, &regs);
 	if (err) {
 		dev_err(dev, "missing \"reg\" property\n");
diff --git a/drivers/pci/pci-bridge-emul.c b/drivers/pci/pci-bridge-emul.c
new file mode 100644
index 000000000000..129738362d90
--- /dev/null
+++ b/drivers/pci/pci-bridge-emul.c
@@ -0,0 +1,408 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2018 Marvell
+ *
+ * Author: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
+ *
+ * This file helps PCI controller drivers implement a fake root port
+ * PCI bridge when the HW doesn't provide such a root port PCI
+ * bridge.
+ *
+ * It emulates a PCI bridge by providing a fake PCI configuration
+ * space (and optionally a PCIe capability configuration space) in
+ * memory. By default the read/write operations simply read and update
+ * this fake configuration space in memory. However, PCI controller
+ * drivers can provide through the 'struct pci_sw_bridge_ops'
+ * structure a set of operations to override or complement this
+ * default behavior.
+ */
+
+#include <linux/pci.h>
+#include "pci-bridge-emul.h"
+
+#define PCI_BRIDGE_CONF_END	PCI_STD_HEADER_SIZEOF
+#define PCI_CAP_PCIE_START	PCI_BRIDGE_CONF_END
+#define PCI_CAP_PCIE_END	(PCI_CAP_PCIE_START + PCI_EXP_SLTSTA2 + 2)
+
+/*
+ * Initialize a pci_bridge_emul structure to represent a fake PCI
+ * bridge configuration space. The caller needs to have initialized
+ * the PCI configuration space with whatever values make sense
+ * (typically at least vendor, device, revision), the ->ops pointer,
+ * and optionally ->data and ->has_pcie.
+ */
+void pci_bridge_emul_init(struct pci_bridge_emul *bridge)
+{
+	bridge->conf.class_revision |= PCI_CLASS_BRIDGE_PCI << 16;
+	bridge->conf.header_type = PCI_HEADER_TYPE_BRIDGE;
+	bridge->conf.cache_line_size = 0x10;
+	bridge->conf.status = PCI_STATUS_CAP_LIST;
+
+	if (bridge->has_pcie) {
+		bridge->conf.capabilities_pointer = PCI_CAP_PCIE_START;
+		bridge->pcie_conf.cap_id = PCI_CAP_ID_EXP;
+		/* Set PCIe v2, root port, slot support */
+		bridge->pcie_conf.cap = PCI_EXP_TYPE_ROOT_PORT << 4 | 2 |
+			PCI_EXP_FLAGS_SLOT;
+	}
+}
+
+struct pci_bridge_reg_behavior {
+	/* Read-only bits */
+	u32 ro;
+
+	/* Read-write bits */
+	u32 rw;
+
+	/* Write-1-to-clear bits */
+	u32 w1c;
+
+	/* Reserved bits (hardwired to 0) */
+	u32 rsvd;
+};
+
+const static struct pci_bridge_reg_behavior pci_regs_behavior[] = {
+	[PCI_VENDOR_ID / 4] = { .ro = ~0 },
+	[PCI_COMMAND / 4] = {
+		.rw = (PCI_COMMAND_IO | PCI_COMMAND_MEMORY |
+		       PCI_COMMAND_MASTER | PCI_COMMAND_PARITY |
+		       PCI_COMMAND_SERR),
+		.ro = ((PCI_COMMAND_SPECIAL | PCI_COMMAND_INVALIDATE |
+			PCI_COMMAND_VGA_PALETTE | PCI_COMMAND_WAIT |
+			PCI_COMMAND_FAST_BACK) |
+		       (PCI_STATUS_CAP_LIST | PCI_STATUS_66MHZ |
+			PCI_STATUS_FAST_BACK | PCI_STATUS_DEVSEL_MASK) << 16),
+		.rsvd = GENMASK(15, 10) | ((BIT(6) | GENMASK(3, 0)) << 16),
+		.w1c = (PCI_STATUS_PARITY |
+			PCI_STATUS_SIG_TARGET_ABORT |
+			PCI_STATUS_REC_TARGET_ABORT |
+			PCI_STATUS_REC_MASTER_ABORT |
+			PCI_STATUS_SIG_SYSTEM_ERROR |
+			PCI_STATUS_DETECTED_PARITY) << 16,
+	},
+	[PCI_CLASS_REVISION / 4] = { .ro = ~0 },
+
+	/*
+	 * Cache Line Size register: implement as read-only, we do not
+	 * pretend implementing "Memory Write and Invalidate"
+	 * transactions"
+	 *
+	 * Latency Timer Register: implemented as read-only, as "A
+	 * bridge that is not capable of a burst transfer of more than
+	 * two data phases on its primary interface is permitted to
+	 * hardwire the Latency Timer to a value of 16 or less"
+	 *
+	 * Header Type: always read-only
+	 *
+	 * BIST register: implemented as read-only, as "A bridge that
+	 * does not support BIST must implement this register as a
+	 * read-only register that returns 0 when read"
+	 */
+	[PCI_CACHE_LINE_SIZE / 4] = { .ro = ~0 },
+
+	/*
+	 * Base Address registers not used must be implemented as
+	 * read-only registers that return 0 when read.
+	 */
+	[PCI_BASE_ADDRESS_0 / 4] = { .ro = ~0 },
+	[PCI_BASE_ADDRESS_1 / 4] = { .ro = ~0 },
+
+	[PCI_PRIMARY_BUS / 4] = {
+		/* Primary, secondary and subordinate bus are RW */
+		.rw = GENMASK(24, 0),
+		/* Secondary latency is read-only */
+		.ro = GENMASK(31, 24),
+	},
+
+	[PCI_IO_BASE / 4] = {
+		/* The high four bits of I/O base/limit are RW */
+		.rw = (GENMASK(15, 12) | GENMASK(7, 4)),
+
+		/* The low four bits of I/O base/limit are RO */
+		.ro = (((PCI_STATUS_66MHZ | PCI_STATUS_FAST_BACK |
+			 PCI_STATUS_DEVSEL_MASK) << 16) |
+		       GENMASK(11, 8) | GENMASK(3, 0)),
+
+		.w1c = (PCI_STATUS_PARITY |
+			PCI_STATUS_SIG_TARGET_ABORT |
+			PCI_STATUS_REC_TARGET_ABORT |
+			PCI_STATUS_REC_MASTER_ABORT |
+			PCI_STATUS_SIG_SYSTEM_ERROR |
+			PCI_STATUS_DETECTED_PARITY) << 16,
+
+		.rsvd = ((BIT(6) | GENMASK(4, 0)) << 16),
+	},
+
+	[PCI_MEMORY_BASE / 4] = {
+		/* The high 12-bits of mem base/limit are RW */
+		.rw = GENMASK(31, 20) | GENMASK(15, 4),
+
+		/* The low four bits of mem base/limit are RO */
+		.ro = GENMASK(19, 16) | GENMASK(3, 0),
+	},
+
+	[PCI_PREF_MEMORY_BASE / 4] = {
+		/* The high 12-bits of pref mem base/limit are RW */
+		.rw = GENMASK(31, 20) | GENMASK(15, 4),
+
+		/* The low four bits of pref mem base/limit are RO */
+		.ro = GENMASK(19, 16) | GENMASK(3, 0),
+	},
+
+	[PCI_PREF_BASE_UPPER32 / 4] = {
+		.rw = ~0,
+	},
+
+	[PCI_PREF_LIMIT_UPPER32 / 4] = {
+		.rw = ~0,
+	},
+
+	[PCI_IO_BASE_UPPER16 / 4] = {
+		.rw = ~0,
+	},
+
+	[PCI_CAPABILITY_LIST / 4] = {
+		.ro = GENMASK(7, 0),
+		.rsvd = GENMASK(31, 8),
+	},
+
+	[PCI_ROM_ADDRESS1 / 4] = {
+		.rw = GENMASK(31, 11) | BIT(0),
+		.rsvd = GENMASK(10, 1),
+	},
+
+	/*
+	 * Interrupt line (bits 7:0) are RW, interrupt pin (bits 15:8)
+	 * are RO, and bridge control (31:16) are a mix of RW, RO,
+	 * reserved and W1C bits
+	 */
+	[PCI_INTERRUPT_LINE / 4] = {
+		/* Interrupt line is RW */
+		.rw = (GENMASK(7, 0) |
+		       ((PCI_BRIDGE_CTL_PARITY |
+			 PCI_BRIDGE_CTL_SERR |
+			 PCI_BRIDGE_CTL_ISA |
+			 PCI_BRIDGE_CTL_VGA |
+			 PCI_BRIDGE_CTL_MASTER_ABORT |
+			 PCI_BRIDGE_CTL_BUS_RESET |
+			 BIT(8) | BIT(9) | BIT(11)) << 16)),
+
+		/* Interrupt pin is RO */
+		.ro = (GENMASK(15, 8) | ((PCI_BRIDGE_CTL_FAST_BACK) << 16)),
+
+		.w1c = BIT(10) << 16,
+
+		.rsvd = (GENMASK(15, 12) | BIT(4)) << 16,
+	},
+};
+
+const static struct pci_bridge_reg_behavior pcie_cap_regs_behavior[] = {
+	[PCI_CAP_LIST_ID / 4] = {
+		/*
+		 * Capability ID, Next Capability Pointer and
+		 * Capabilities register are all read-only.
+		 */
+		.ro = ~0,
+	},
+
+	[PCI_EXP_DEVCAP / 4] = {
+		.ro = ~0,
+	},
+
+	[PCI_EXP_DEVCTL / 4] = {
+		/* Device control register is RW */
+		.rw = GENMASK(15, 0),
+
+		/*
+		 * Device status register has 4 bits W1C, then 2 bits
+		 * RO, the rest is reserved
+		 */
+		.w1c = GENMASK(19, 16),
+		.ro = GENMASK(20, 19),
+		.rsvd = GENMASK(31, 21),
+	},
+
+	[PCI_EXP_LNKCAP / 4] = {
+		/* All bits are RO, except bit 23 which is reserved */
+		.ro = lower_32_bits(~BIT(23)),
+		.rsvd = BIT(23),
+	},
+
+	[PCI_EXP_LNKCTL / 4] = {
+		/*
+		 * Link control has bits [1:0] and [11:3] RW, the
+		 * other bits are reserved.
+		 * Link status has bits [13:0] RO, and bits [14:15]
+		 * W1C.
+		 */
+		.rw = GENMASK(11, 3) | GENMASK(1, 0),
+		.ro = GENMASK(13, 0) << 16,
+		.w1c = GENMASK(15, 14) << 16,
+		.rsvd = GENMASK(15, 12) | BIT(2),
+	},
+
+	[PCI_EXP_SLTCAP / 4] = {
+		.ro = ~0,
+	},
+
+	[PCI_EXP_SLTCTL / 4] = {
+		/*
+		 * Slot control has bits [12:0] RW, the rest is
+		 * reserved.
+		 *
+		 * Slot status has a mix of W1C and RO bits, as well
+		 * as reserved bits.
+		 */
+		.rw = GENMASK(12, 0),
+		.w1c = (PCI_EXP_SLTSTA_ABP | PCI_EXP_SLTSTA_PFD |
+			PCI_EXP_SLTSTA_MRLSC | PCI_EXP_SLTSTA_PDC |
+			PCI_EXP_SLTSTA_CC | PCI_EXP_SLTSTA_DLLSC) << 16,
+		.ro = (PCI_EXP_SLTSTA_MRLSS | PCI_EXP_SLTSTA_PDS |
+		       PCI_EXP_SLTSTA_EIS) << 16,
+		.rsvd = GENMASK(15, 12) | (GENMASK(15, 9) << 16),
+	},
+
+	[PCI_EXP_RTCTL / 4] = {
+		/*
+		 * Root control has bits [4:0] RW, the rest is
+		 * reserved.
+		 *
+		 * Root status has bit 0 RO, the rest is reserved.
+		 */
+		.rw = (PCI_EXP_RTCTL_SECEE | PCI_EXP_RTCTL_SENFEE |
+		       PCI_EXP_RTCTL_SEFEE | PCI_EXP_RTCTL_PMEIE |
+		       PCI_EXP_RTCTL_CRSSVE),
+		.ro = PCI_EXP_RTCAP_CRSVIS << 16,
+		.rsvd = GENMASK(15, 5) | (GENMASK(15, 1) << 16),
+	},
+
+	[PCI_EXP_RTSTA / 4] = {
+		.ro = GENMASK(15, 0) | PCI_EXP_RTSTA_PENDING,
+		.w1c = PCI_EXP_RTSTA_PME,
+		.rsvd = GENMASK(31, 18),
+	},
+};
+
+/*
+ * Should be called by the PCI controller driver when reading the PCI
+ * configuration space of the fake bridge. It will call back the
+ * ->ops->read_base or ->ops->read_pcie operations.
+ */
+int pci_bridge_emul_conf_read(struct pci_bridge_emul *bridge, int where,
+			      int size, u32 *value)
+{
+	int ret;
+	int reg = where & ~3;
+	pci_bridge_emul_read_status_t (*read_op)(struct pci_bridge_emul *bridge,
+						 int reg, u32 *value);
+	u32 *cfgspace;
+	const struct pci_bridge_reg_behavior *behavior;
+
+	if (bridge->has_pcie && reg >= PCI_CAP_PCIE_END) {
+		*value = 0;
+		return PCIBIOS_SUCCESSFUL;
+	}
+
+	if (!bridge->has_pcie && reg >= PCI_BRIDGE_CONF_END) {
+		*value = 0;
+		return PCIBIOS_SUCCESSFUL;
+	}
+
+	if (bridge->has_pcie && reg >= PCI_CAP_PCIE_START) {
+		reg -= PCI_CAP_PCIE_START;
+		read_op = bridge->ops->read_pcie;
+		cfgspace = (u32 *) &bridge->pcie_conf;
+		behavior = pcie_cap_regs_behavior;
+	} else {
+		read_op = bridge->ops->read_base;
+		cfgspace = (u32 *) &bridge->conf;
+		behavior = pci_regs_behavior;
+	}
+
+	if (read_op)
+		ret = read_op(bridge, reg, value);
+	else
+		ret = PCI_BRIDGE_EMUL_NOT_HANDLED;
+
+	if (ret == PCI_BRIDGE_EMUL_NOT_HANDLED)
+		*value = cfgspace[reg / 4];
+
+	/*
+	 * Make sure we never return any reserved bit with a value
+	 * different from 0.
+	 */
+	*value &= ~behavior[reg / 4].rsvd;
+
+	if (size == 1)
+		*value = (*value >> (8 * (where & 3))) & 0xff;
+	else if (size == 2)
+		*value = (*value >> (8 * (where & 3))) & 0xffff;
+	else if (size != 4)
+		return PCIBIOS_BAD_REGISTER_NUMBER;
+
+	return PCIBIOS_SUCCESSFUL;
+}
+
+/*
+ * Should be called by the PCI controller driver when writing the PCI
+ * configuration space of the fake bridge. It will call back the
+ * ->ops->write_base or ->ops->write_pcie operations.
+ */
+int pci_bridge_emul_conf_write(struct pci_bridge_emul *bridge, int where,
+			       int size, u32 value)
+{
+	int reg = where & ~3;
+	int mask, ret, old, new, shift;
+	void (*write_op)(struct pci_bridge_emul *bridge, int reg,
+			 u32 old, u32 new, u32 mask);
+	u32 *cfgspace;
+	const struct pci_bridge_reg_behavior *behavior;
+
+	if (bridge->has_pcie && reg >= PCI_CAP_PCIE_END)
+		return PCIBIOS_SUCCESSFUL;
+
+	if (!bridge->has_pcie && reg >= PCI_BRIDGE_CONF_END)
+		return PCIBIOS_SUCCESSFUL;
+
+	shift = (where & 0x3) * 8;
+
+	if (size == 4)
+		mask = 0xffffffff;
+	else if (size == 2)
+		mask = 0xffff << shift;
+	else if (size == 1)
+		mask = 0xff << shift;
+	else
+		return PCIBIOS_BAD_REGISTER_NUMBER;
+
+	ret = pci_bridge_emul_conf_read(bridge, reg, 4, &old);
+	if (ret != PCIBIOS_SUCCESSFUL)
+		return ret;
+
+	if (bridge->has_pcie && reg >= PCI_CAP_PCIE_START) {
+		reg -= PCI_CAP_PCIE_START;
+		write_op = bridge->ops->write_pcie;
+		cfgspace = (u32 *) &bridge->pcie_conf;
+		behavior = pcie_cap_regs_behavior;
+	} else {
+		write_op = bridge->ops->write_base;
+		cfgspace = (u32 *) &bridge->conf;
+		behavior = pci_regs_behavior;
+	}
+
+	/* Keep all bits, except the RW bits */
+	new = old & (~mask | ~behavior[reg / 4].rw);
+
+	/* Update the value of the RW bits */
+	new |= (value << shift) & (behavior[reg / 4].rw & mask);
+
+	/* Clear the W1C bits */
+	new &= ~((value << shift) & (behavior[reg / 4].w1c & mask));
+
+	cfgspace[reg / 4] = new;
+
+	if (write_op)
+		write_op(bridge, reg, old, new, mask);
+
+	return PCIBIOS_SUCCESSFUL;
+}
diff --git a/drivers/pci/pci-bridge-emul.h b/drivers/pci/pci-bridge-emul.h
new file mode 100644
index 000000000000..9d510ccf738b
--- /dev/null
+++ b/drivers/pci/pci-bridge-emul.h
@@ -0,0 +1,124 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __PCI_BRIDGE_EMUL_H__
+#define __PCI_BRIDGE_EMUL_H__
+
+#include <linux/kernel.h>
+
+/* PCI configuration space of a PCI-to-PCI bridge. */
+struct pci_bridge_emul_conf {
+	u16 vendor;
+	u16 device;
+	u16 command;
+	u16 status;
+	u32 class_revision;
+	u8 cache_line_size;
+	u8 latency_timer;
+	u8 header_type;
+	u8 bist;
+	u32 bar[2];
+	u8 primary_bus;
+	u8 secondary_bus;
+	u8 subordinate_bus;
+	u8 secondary_latency_timer;
+	u8 iobase;
+	u8 iolimit;
+	u16 secondary_status;
+	u16 membase;
+	u16 memlimit;
+	u16 pref_mem_base;
+	u16 pref_mem_limit;
+	u32 prefbaseupper;
+	u32 preflimitupper;
+	u16 iobaseupper;
+	u16 iolimitupper;
+	u8 capabilities_pointer;
+	u8 reserve[3];
+	u32 romaddr;
+	u8 intline;
+	u8 intpin;
+	u16 bridgectrl;
+};
+
+/* PCI configuration space of the PCIe capabilities */
+struct pci_bridge_emul_pcie_conf {
+	u8 cap_id;
+	u8 next;
+	u16 cap;
+	u32 devcap;
+	u16 devctl;
+	u16 devsta;
+	u32 lnkcap;
+	u16 lnkctl;
+	u16 lnksta;
+	u32 slotcap;
+	u16 slotctl;
+	u16 slotsta;
+	u16 rootctl;
+	u16 rsvd;
+	u32 rootsta;
+	u32 devcap2;
+	u16 devctl2;
+	u16 devsta2;
+	u32 lnkcap2;
+	u16 lnkctl2;
+	u16 lnksta2;
+	u32 slotcap2;
+	u16 slotctl2;
+	u16 slotsta2;
+};
+
+struct pci_bridge_emul;
+
+typedef enum { PCI_BRIDGE_EMUL_HANDLED,
+	       PCI_BRIDGE_EMUL_NOT_HANDLED } pci_bridge_emul_read_status_t;
+
+struct pci_bridge_emul_ops {
+	/*
+	 * Called when reading from the regular PCI bridge
+	 * configuration space. Return PCI_BRIDGE_EMUL_HANDLED when the
+	 * operation has handled the read operation and filled in the
+	 * *value, or PCI_BRIDGE_EMUL_NOT_HANDLED when the read should
+	 * be emulated by the common code by reading from the
+	 * in-memory copy of the configuration space.
+	 */
+	pci_bridge_emul_read_status_t (*read_base)(struct pci_bridge_emul *bridge,
+						   int reg, u32 *value);
+
+	/*
+	 * Same as ->read_base(), except it is for reading from the
+	 * PCIe capability configuration space.
+	 */
+	pci_bridge_emul_read_status_t (*read_pcie)(struct pci_bridge_emul *bridge,
+						   int reg, u32 *value);
+	/*
+	 * Called when writing to the regular PCI bridge configuration
+	 * space. old is the current value, new is the new value being
+	 * written, and mask indicates which parts of the value are
+	 * being changed.
+	 */
+	void (*write_base)(struct pci_bridge_emul *bridge, int reg,
+			   u32 old, u32 new, u32 mask);
+
+	/*
+	 * Same as ->write_base(), except it is for writing from the
+	 * PCIe capability configuration space.
+	 */
+	void (*write_pcie)(struct pci_bridge_emul *bridge, int reg,
+			   u32 old, u32 new, u32 mask);
+};
+
+struct pci_bridge_emul {
+	struct pci_bridge_emul_conf conf;
+	struct pci_bridge_emul_pcie_conf pcie_conf;
+	struct pci_bridge_emul_ops *ops;
+	void *data;
+	bool has_pcie;
+};
+
+void pci_bridge_emul_init(struct pci_bridge_emul *bridge);
+int pci_bridge_emul_conf_read(struct pci_bridge_emul *bridge, int where,
+			      int size, u32 *value);
+int pci_bridge_emul_conf_write(struct pci_bridge_emul *bridge, int where,
+			       int size, u32 value);
+
+#endif /* __PCI_BRIDGE_EMUL_H__ */