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From 1fc02559de87cd88339a83ad05baa9c2b5bd1ac0 Mon Sep 17 00:00:00 2001
From: Jayachandran C <jchandra@broadcom.com>
Date: Fri, 10 Jun 2016 21:55:09 +0200
Subject: [PATCH 01/11] PCI/ECAM: Move ecam.h to linux/include/pci-ecam.h

This header will be used from arch/arm64 for ACPI PCI implementation
so it needs to be moved out of drivers/pci.

Update users of the header file to use the new name. No functional
changes.

Signed-off-by: Jayachandran C <jchandra@broadcom.com>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
---
 drivers/pci/ecam.c                  |  3 +-
 drivers/pci/ecam.h                  | 67 -------------------------------------
 drivers/pci/host/pci-host-common.c  |  3 +-
 drivers/pci/host/pci-host-generic.c |  3 +-
 drivers/pci/host/pci-thunder-ecam.c |  3 +-
 drivers/pci/host/pci-thunder-pem.c  |  3 +-
 include/linux/pci-ecam.h            | 67 +++++++++++++++++++++++++++++++++++++
 7 files changed, 72 insertions(+), 77 deletions(-)
 delete mode 100644 drivers/pci/ecam.h
 create mode 100644 include/linux/pci-ecam.h

diff --git a/drivers/pci/ecam.c b/drivers/pci/ecam.c
index f9832ad..820e26b 100644
--- a/drivers/pci/ecam.c
+++ b/drivers/pci/ecam.c
@@ -19,10 +19,9 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/pci.h>
+#include <linux/pci-ecam.h>
 #include <linux/slab.h>
 
-#include "ecam.h"
-
 /*
  * On 64-bit systems, we do a single ioremap for the whole config space
  * since we have enough virtual address range available.  On 32-bit, we
diff --git a/drivers/pci/ecam.h b/drivers/pci/ecam.h
deleted file mode 100644
index 9878beb..0000000
--- a/drivers/pci/ecam.h
+++ /dev/null
@@ -1,67 +0,0 @@
-/*
- * Copyright 2016 Broadcom
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License, version 2, as
- * published by the Free Software Foundation (the "GPL").
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * General Public License version 2 (GPLv2) for more details.
- *
- * You should have received a copy of the GNU General Public License
- * version 2 (GPLv2) along with this source code.
- */
-#ifndef DRIVERS_PCI_ECAM_H
-#define DRIVERS_PCI_ECAM_H
-
-#include <linux/kernel.h>
-#include <linux/platform_device.h>
-
-/*
- * struct to hold pci ops and bus shift of the config window
- * for a PCI controller.
- */
-struct pci_config_window;
-struct pci_ecam_ops {
-	unsigned int			bus_shift;
-	struct pci_ops			pci_ops;
-	int				(*init)(struct device *,
-						struct pci_config_window *);
-};
-
-/*
- * struct to hold the mappings of a config space window. This
- * is expected to be used as sysdata for PCI controllers that
- * use ECAM.
- */
-struct pci_config_window {
-	struct resource			res;
-	struct resource			busr;
-	void				*priv;
-	struct pci_ecam_ops		*ops;
-	union {
-		void __iomem		*win;	/* 64-bit single mapping */
-		void __iomem		**winp; /* 32-bit per-bus mapping */
-	};
-};
-
-/* create and free pci_config_window */
-struct pci_config_window *pci_ecam_create(struct device *dev,
-		struct resource *cfgres, struct resource *busr,
-		struct pci_ecam_ops *ops);
-void pci_ecam_free(struct pci_config_window *cfg);
-
-/* map_bus when ->sysdata is an instance of pci_config_window */
-void __iomem *pci_ecam_map_bus(struct pci_bus *bus, unsigned int devfn,
-			       int where);
-/* default ECAM ops */
-extern struct pci_ecam_ops pci_generic_ecam_ops;
-
-#ifdef CONFIG_PCI_HOST_GENERIC
-/* for DT-based PCI controllers that support ECAM */
-int pci_host_common_probe(struct platform_device *pdev,
-			  struct pci_ecam_ops *ops);
-#endif
-#endif
diff --git a/drivers/pci/host/pci-host-common.c b/drivers/pci/host/pci-host-common.c
index 8cba7ab..c18b9e3 100644
--- a/drivers/pci/host/pci-host-common.c
+++ b/drivers/pci/host/pci-host-common.c
@@ -20,10 +20,9 @@
 #include <linux/module.h>
 #include <linux/of_address.h>
 #include <linux/of_pci.h>
+#include <linux/pci-ecam.h>
 #include <linux/platform_device.h>
 
-#include "../ecam.h"
-
 static int gen_pci_parse_request_of_pci_ranges(struct device *dev,
 		       struct list_head *resources, struct resource **bus_range)
 {
diff --git a/drivers/pci/host/pci-host-generic.c b/drivers/pci/host/pci-host-generic.c
index 6eaceab..f0ca6de 100644
--- a/drivers/pci/host/pci-host-generic.c
+++ b/drivers/pci/host/pci-host-generic.c
@@ -23,10 +23,9 @@
 #include <linux/module.h>
 #include <linux/of_address.h>
 #include <linux/of_pci.h>
+#include <linux/pci-ecam.h>
 #include <linux/platform_device.h>
 
-#include "../ecam.h"
-
 static struct pci_ecam_ops gen_pci_cfg_cam_bus_ops = {
 	.bus_shift	= 16,
 	.pci_ops	= {
diff --git a/drivers/pci/host/pci-thunder-ecam.c b/drivers/pci/host/pci-thunder-ecam.c
index 540d030..a9fc1c9 100644
--- a/drivers/pci/host/pci-thunder-ecam.c
+++ b/drivers/pci/host/pci-thunder-ecam.c
@@ -11,10 +11,9 @@
 #include <linux/ioport.h>
 #include <linux/of_pci.h>
 #include <linux/of.h>
+#include <linux/pci-ecam.h>
 #include <linux/platform_device.h>
 
-#include "../ecam.h"
-
 static void set_val(u32 v, int where, int size, u32 *val)
 {
 	int shift = (where & 3) * 8;
diff --git a/drivers/pci/host/pci-thunder-pem.c b/drivers/pci/host/pci-thunder-pem.c
index 9b8ab94..5020d3d 100644
--- a/drivers/pci/host/pci-thunder-pem.c
+++ b/drivers/pci/host/pci-thunder-pem.c
@@ -18,10 +18,9 @@
 #include <linux/module.h>
 #include <linux/of_address.h>
 #include <linux/of_pci.h>
+#include <linux/pci-ecam.h>
 #include <linux/platform_device.h>
 
-#include "../ecam.h"
-
 #define PEM_CFG_WR 0x28
 #define PEM_CFG_RD 0x30
 
diff --git a/include/linux/pci-ecam.h b/include/linux/pci-ecam.h
new file mode 100644
index 0000000..9878beb
--- /dev/null
+++ b/include/linux/pci-ecam.h
@@ -0,0 +1,67 @@
+/*
+ * Copyright 2016 Broadcom
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2, as
+ * published by the Free Software Foundation (the "GPL").
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License version 2 (GPLv2) for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * version 2 (GPLv2) along with this source code.
+ */
+#ifndef DRIVERS_PCI_ECAM_H
+#define DRIVERS_PCI_ECAM_H
+
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+
+/*
+ * struct to hold pci ops and bus shift of the config window
+ * for a PCI controller.
+ */
+struct pci_config_window;
+struct pci_ecam_ops {
+	unsigned int			bus_shift;
+	struct pci_ops			pci_ops;
+	int				(*init)(struct device *,
+						struct pci_config_window *);
+};
+
+/*
+ * struct to hold the mappings of a config space window. This
+ * is expected to be used as sysdata for PCI controllers that
+ * use ECAM.
+ */
+struct pci_config_window {
+	struct resource			res;
+	struct resource			busr;
+	void				*priv;
+	struct pci_ecam_ops		*ops;
+	union {
+		void __iomem		*win;	/* 64-bit single mapping */
+		void __iomem		**winp; /* 32-bit per-bus mapping */
+	};
+};
+
+/* create and free pci_config_window */
+struct pci_config_window *pci_ecam_create(struct device *dev,
+		struct resource *cfgres, struct resource *busr,
+		struct pci_ecam_ops *ops);
+void pci_ecam_free(struct pci_config_window *cfg);
+
+/* map_bus when ->sysdata is an instance of pci_config_window */
+void __iomem *pci_ecam_map_bus(struct pci_bus *bus, unsigned int devfn,
+			       int where);
+/* default ECAM ops */
+extern struct pci_ecam_ops pci_generic_ecam_ops;
+
+#ifdef CONFIG_PCI_HOST_GENERIC
+/* for DT-based PCI controllers that support ECAM */
+int pci_host_common_probe(struct platform_device *pdev,
+			  struct pci_ecam_ops *ops);
+#endif
+#endif
-- 
2.7.4

From 5eb9996fc097629854f359f9ad3d959fdacb7f8f Mon Sep 17 00:00:00 2001
From: Jayachandran C <jchandra@broadcom.com>
Date: Fri, 10 Jun 2016 21:55:10 +0200
Subject: [PATCH 02/11] PCI/ECAM: Add parent device field to pci_config_window

Add a parent device field to struct pci_config_window. The parent
is not saved now, but will be useful to save it in some cases.
Specifically in case of ACPI for ARM64, it can be used to setup
ACPI companion and domain.

Since the parent dev is in struct pci_config_window now, we need
not pass it to the init function as a separate argument.

Signed-off-by: Jayachandran C <jchandra@broadcom.com>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
---
 drivers/pci/ecam.c                 | 3 ++-
 drivers/pci/host/pci-thunder-pem.c | 3 ++-
 include/linux/pci-ecam.h           | 4 ++--
 3 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/ecam.c b/drivers/pci/ecam.c
index 820e26b..66e0d71 100644
--- a/drivers/pci/ecam.c
+++ b/drivers/pci/ecam.c
@@ -51,6 +51,7 @@ struct pci_config_window *pci_ecam_create(struct device *dev,
 	if (!cfg)
 		return ERR_PTR(-ENOMEM);
 
+	cfg->parent = dev;
 	cfg->ops = ops;
 	cfg->busr.start = busr->start;
 	cfg->busr.end = busr->end;
@@ -94,7 +95,7 @@ struct pci_config_window *pci_ecam_create(struct device *dev,
 	}
 
 	if (ops->init) {
-		err = ops->init(dev, cfg);
+		err = ops->init(cfg);
 		if (err)
 			goto err_exit;
 	}
diff --git a/drivers/pci/host/pci-thunder-pem.c b/drivers/pci/host/pci-thunder-pem.c
index 5020d3d..91f6fc6 100644
--- a/drivers/pci/host/pci-thunder-pem.c
+++ b/drivers/pci/host/pci-thunder-pem.c
@@ -284,8 +284,9 @@ static int thunder_pem_config_write(struct pci_bus *bus, unsigned int devfn,
 	return pci_generic_config_write(bus, devfn, where, size, val);
 }
 
-static int thunder_pem_init(struct device *dev, struct pci_config_window *cfg)
+static int thunder_pem_init(struct pci_config_window *cfg)
 {
+	struct device *dev = cfg->parent;
 	resource_size_t bar4_start;
 	struct resource *res_pem;
 	struct thunder_pem_pci *pem_pci;
diff --git a/include/linux/pci-ecam.h b/include/linux/pci-ecam.h
index 9878beb..7adad20 100644
--- a/include/linux/pci-ecam.h
+++ b/include/linux/pci-ecam.h
@@ -27,8 +27,7 @@ struct pci_config_window;
 struct pci_ecam_ops {
 	unsigned int			bus_shift;
 	struct pci_ops			pci_ops;
-	int				(*init)(struct device *,
-						struct pci_config_window *);
+	int				(*init)(struct pci_config_window *);
 };
 
 /*
@@ -45,6 +44,7 @@ struct pci_config_window {
 		void __iomem		*win;	/* 64-bit single mapping */
 		void __iomem		**winp; /* 32-bit per-bus mapping */
 	};
+	struct device			*parent;/* ECAM res was from this dev */
 };
 
 /* create and free pci_config_window */
-- 
2.7.4

From 6ed6c1365df5c9201e9b275e8ed4eaa64ef2ec0d Mon Sep 17 00:00:00 2001
From: Sinan Kaya <okaya@codeaurora.org>
Date: Fri, 10 Jun 2016 21:55:11 +0200
Subject: [PATCH 03/11] PCI: Add new function to unmap IO resources

We need to release I/O resources so that the same I/O resources
can be allocated again in pci_remap_iospace(), like in PCI hotplug removal
scenario. Therefore implement new pci_unmap_iospace() call which
unmaps I/O space as the symmetry to pci_remap_iospace().

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
---
 drivers/pci/pci.c   | 18 ++++++++++++++++++
 include/linux/pci.h |  1 +
 2 files changed, 19 insertions(+)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index c8b4dbd..eb431b5 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -25,6 +25,7 @@
 #include <linux/device.h>
 #include <linux/pm_runtime.h>
 #include <linux/pci_hotplug.h>
+#include <linux/vmalloc.h>
 #include <asm/setup.h>
 #include <linux/aer.h>
 #include "pci.h"
@@ -3165,6 +3166,23 @@ int __weak pci_remap_iospace(const struct resource *res, phys_addr_t phys_addr)
 #endif
 }
 
+/**
+ *	pci_unmap_iospace - Unmap the memory mapped I/O space
+ *	@res: resource to be unmapped
+ *
+ *	Unmap the CPU virtual address @res from virtual address space.
+ *	Only architectures that have memory mapped IO functions defined
+ *	(and the PCI_IOBASE value defined) should call this function.
+ */
+void pci_unmap_iospace(struct resource *res)
+{
+#if defined(PCI_IOBASE) && defined(CONFIG_MMU)
+	unsigned long vaddr = (unsigned long)PCI_IOBASE + res->start;
+
+	unmap_kernel_range(vaddr, resource_size(res));
+#endif
+}
+
 static void __pci_set_master(struct pci_dev *dev, bool enable)
 {
 	u16 old_cmd, cmd;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index b67e4df..12349de 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1167,6 +1167,7 @@ int pci_register_io_range(phys_addr_t addr, resource_size_t size);
 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);
 
 static inline pci_bus_addr_t pci_bus_address(struct pci_dev *pdev, int bar)
 {
-- 
2.7.4

From 62f4d54fc2d2882b9ebaa920189574f422e12207 Mon Sep 17 00:00:00 2001
From: Jayachandran C <jchandra@broadcom.com>
Date: Fri, 10 Jun 2016 21:55:12 +0200
Subject: [PATCH 04/11] ACPI/PCI: Support IO resources when parsing PCI host
 bridge resources

Platforms that have memory mapped IO port (such as ARM64) need special
handling for PCI I/O resources. For host bridge's resource probing case
these resources need to be fixed up with
pci_register_io_range()/pci_remap_iospace() etc.

The same I/O resources need to be released after hotplug
removal so that it can be re-added back by the pci_remap_iospace()
function during insertion. As a consequence unmap I/O resources
with pci_unmap_iospace() when we release host bridge resources.

Signed-off-by: Jayachandran C <jchandra@broadcom.com>
Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
[ Tomasz: merged in Sinan's patch to unmap IO resources properly, updated changelog]
Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
---
 drivers/acpi/pci_root.c | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index ae3fe4e..9a26dd1 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -720,6 +720,40 @@ next:
 	}
 }
 
+#ifdef PCI_IOBASE
+static void acpi_pci_root_remap_iospace(struct resource_entry *entry)
+{
+	struct resource *res = entry->res;
+	resource_size_t cpu_addr = res->start;
+	resource_size_t pci_addr = cpu_addr - entry->offset;
+	resource_size_t length = resource_size(res);
+	unsigned long port;
+
+	if (pci_register_io_range(cpu_addr, length))
+		goto err;
+
+	port = pci_address_to_pio(cpu_addr);
+	if (port == (unsigned long)-1)
+		goto err;
+
+	res->start = port;
+	res->end = port + length - 1;
+	entry->offset = port - pci_addr;
+
+	if (pci_remap_iospace(res, cpu_addr) < 0)
+		goto err;
+
+	pr_info("Remapped I/O %pa to %pR\n", &cpu_addr, res);
+	return;
+err:
+	res->flags |= IORESOURCE_DISABLED;
+}
+#else
+static inline void acpi_pci_root_remap_iospace(struct resource_entry *entry)
+{
+}
+#endif
+
 int acpi_pci_probe_root_resources(struct acpi_pci_root_info *info)
 {
 	int ret;
@@ -740,6 +774,9 @@ int acpi_pci_probe_root_resources(struct acpi_pci_root_info *info)
 			"no IO and memory resources present in _CRS\n");
 	else {
 		resource_list_for_each_entry_safe(entry, tmp, list) {
+			if (entry->res->flags & IORESOURCE_IO)
+				acpi_pci_root_remap_iospace(entry);
+
 			if (entry->res->flags & IORESOURCE_DISABLED)
 				resource_list_destroy_entry(entry);
 			else
@@ -811,6 +848,8 @@ static void acpi_pci_root_release_info(struct pci_host_bridge *bridge)
 
 	resource_list_for_each_entry(entry, &bridge->windows) {
 		res = entry->res;
+		if (res->flags & IORESOURCE_IO)
+			pci_unmap_iospace(res);
 		if (res->parent &&
 		    (res->flags & (IORESOURCE_MEM | IORESOURCE_IO)))
 			release_resource(res);
-- 
2.7.4

From dd4f7822d702cca83baa1de7a5f69344ffb82af9 Mon Sep 17 00:00:00 2001
From: Tomasz Nowicki <tn@semihalf.com>
Date: Fri, 10 Jun 2016 21:55:13 +0200
Subject: [PATCH 05/11] ACPI/PCI: Add generic MCFG table handling

According to PCI firmware specifications, on systems booting with ACPI,
PCI configuration for a host bridge must be set-up through the MCFG table
regions for non-hotpluggable bridges and _CBA method for hotpluggable ones.

Current MCFG table handling code, as implemented for x86, cannot be
easily generalized owing to x86 specific quirks handling and related
code, which makes it hard to reuse on other architectures.

In order to implement MCFG PCI configuration handling for new platforms
booting with ACPI (eg ARM64) this patch re-implements MCFG handling from
scratch in a streamlined fashion and provides (through a generic
interface available to all arches):

- Simplified MCFG table parsing (executed through the pci_mmcfg_late_init()
  hook as in current x86)
- MCFG regions look-up interface through domain:bus_start:bus_end tuple

The new MCFG regions handling interface is added to generic ACPI code
so that existing architectures (eg x86) can be moved over to it and
architectures relying on MCFG for ACPI PCI config space can rely on it
without having to resort to arch specific implementations.

Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
Signed-off-by: Jayachandran C <jchandra@broadcom.com>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
---
 drivers/acpi/Kconfig     |  3 ++
 drivers/acpi/Makefile    |  1 +
 drivers/acpi/pci_mcfg.c  | 92 ++++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/pci-acpi.h |  2 ++
 include/linux/pci.h      |  2 +-
 5 files changed, 99 insertions(+), 1 deletion(-)
 create mode 100644 drivers/acpi/pci_mcfg.c

diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index b7e2e77..f98c328 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -217,6 +217,9 @@ config ACPI_PROCESSOR_IDLE
 	bool
 	select CPU_IDLE
 
+config ACPI_MCFG
+	bool
+
 config ACPI_CPPC_LIB
 	bool
 	depends on ACPI_PROCESSOR
diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 251ce85..632e81f 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -40,6 +40,7 @@ acpi-$(CONFIG_ARCH_MIGHT_HAVE_ACPI_PDC) += processor_pdc.o
 acpi-y				+= ec.o
 acpi-$(CONFIG_ACPI_DOCK)	+= dock.o
 acpi-y				+= pci_root.o pci_link.o pci_irq.o
+obj-$(CONFIG_ACPI_MCFG)		+= pci_mcfg.o
 acpi-y				+= acpi_lpss.o acpi_apd.o
 acpi-y				+= acpi_platform.o
 acpi-y				+= acpi_pnp.o
diff --git a/drivers/acpi/pci_mcfg.c b/drivers/acpi/pci_mcfg.c
new file mode 100644
index 0000000..d3c3e85
--- /dev/null
+++ b/drivers/acpi/pci_mcfg.c
@@ -0,0 +1,92 @@
+/*
+ * Copyright (C) 2016 Broadcom
+ *	Author: Jayachandran C <jchandra@broadcom.com>
+ * Copyright (C) 2016 Semihalf
+ * 	Author: Tomasz Nowicki <tn@semihalf.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2, as
+ * published by the Free Software Foundation (the "GPL").
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License version 2 (GPLv2) for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * version 2 (GPLv2) along with this source code.
+ */
+
+#define pr_fmt(fmt) "ACPI: " fmt
+
+#include <linux/kernel.h>
+#include <linux/pci.h>
+#include <linux/pci-acpi.h>
+
+/* Structure to hold entries from the MCFG table */
+struct mcfg_entry {
+	struct list_head	list;
+	phys_addr_t		addr;
+	u16			segment;
+	u8			bus_start;
+	u8			bus_end;
+};
+
+/* List to save mcfg entries */
+static LIST_HEAD(pci_mcfg_list);
+
+phys_addr_t pci_mcfg_lookup(u16 seg, struct resource *bus_res)
+{
+	struct mcfg_entry *e;
+
+	/*
+	 * We expect exact match, unless MCFG entry end bus covers more than
+	 * specified by caller.
+	 */
+	list_for_each_entry(e, &pci_mcfg_list, list) {
+		if (e->segment == seg && e->bus_start == bus_res->start &&
+		    e->bus_end >= bus_res->end)
+			return e->addr;
+	}
+
+	return 0;
+}
+
+static __init int pci_mcfg_parse(struct acpi_table_header *header)
+{
+	struct acpi_table_mcfg *mcfg;
+	struct acpi_mcfg_allocation *mptr;
+	struct mcfg_entry *e, *arr;
+	int i, n;
+
+	if (header->length < sizeof(struct acpi_table_mcfg))
+		return -EINVAL;
+
+	n = (header->length - sizeof(struct acpi_table_mcfg)) /
+					sizeof(struct acpi_mcfg_allocation);
+	mcfg = (struct acpi_table_mcfg *)header;
+	mptr = (struct acpi_mcfg_allocation *) &mcfg[1];
+
+	arr = kcalloc(n, sizeof(*arr), GFP_KERNEL);
+	if (!arr)
+		return -ENOMEM;
+
+	for (i = 0, e = arr; i < n; i++, mptr++, e++) {
+		e->segment = mptr->pci_segment;
+		e->addr =  mptr->address;
+		e->bus_start = mptr->start_bus_number;
+		e->bus_end = mptr->end_bus_number;
+		list_add(&e->list, &pci_mcfg_list);
+	}
+
+	pr_info("MCFG table detected, %d entries\n", n);
+	return 0;
+}
+
+/* Interface called by ACPI - parse and save MCFG table */
+void __init pci_mmcfg_late_init(void)
+{
+	int err = acpi_table_parse(ACPI_SIG_MCFG, pci_mcfg_parse);
+	if (err)
+		pr_err("Failed to parse MCFG (%d)\n", err);
+}
diff --git a/include/linux/pci-acpi.h b/include/linux/pci-acpi.h
index 89ab057..7d63a66 100644
--- a/include/linux/pci-acpi.h
+++ b/include/linux/pci-acpi.h
@@ -24,6 +24,8 @@ static inline acpi_status pci_acpi_remove_pm_notifier(struct acpi_device *dev)
 }
 extern phys_addr_t acpi_pci_root_get_mcfg_addr(acpi_handle handle);
 
+extern phys_addr_t pci_mcfg_lookup(u16 domain, struct resource *bus_res);
+
 static inline acpi_handle acpi_find_root_bridge_handle(struct pci_dev *pdev)
 {
 	struct pci_bus *pbus = pdev->bus;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 12349de..ce03d65 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1723,7 +1723,7 @@ void pcibios_free_irq(struct pci_dev *dev);
 extern struct dev_pm_ops pcibios_pm_ops;
 #endif
 
-#ifdef CONFIG_PCI_MMCONFIG
+#if defined(CONFIG_PCI_MMCONFIG) || defined(CONFIG_ACPI_MCFG)
 void __init pci_mmcfg_early_init(void);
 void __init pci_mmcfg_late_init(void);
 #else
-- 
2.7.4

From fc1907f9c79f9a0a0c2f4d579896e678915fec48 Mon Sep 17 00:00:00 2001
From: Tomasz Nowicki <tn@semihalf.com>
Date: Fri, 10 Jun 2016 21:55:14 +0200
Subject: [PATCH 06/11] PCI: Refactor generic bus domain assignment

Change the way PCI bus domain number is assigned and improve function
name to reflect what function does. No functional changes.

Instead of assigning bus domain number inside of pci_bus_assign_domain_nr()
simply return domain number and let pci_create_root_bus() do assignment.
This way pci_create_root_bus() setups bus structure data in the consistent
way. Since pci_bus_assign_domain_nr() now does not assign but retrieves
domain number instead, rename it to pci_bus_find_domain_nr().

Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
---
 drivers/pci/pci.c   | 4 ++--
 drivers/pci/probe.c | 4 +++-
 include/linux/pci.h | 7 +------
 3 files changed, 6 insertions(+), 9 deletions(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index eb431b5..b9a7833 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -4941,7 +4941,7 @@ int pci_get_new_domain_nr(void)
 }
 
 #ifdef CONFIG_PCI_DOMAINS_GENERIC
-void pci_bus_assign_domain_nr(struct pci_bus *bus, struct device *parent)
+int pci_bus_find_domain_nr(struct pci_bus *bus, struct device *parent)
 {
 	static int use_dt_domains = -1;
 	int domain = -1;
@@ -4985,7 +4985,7 @@ void pci_bus_assign_domain_nr(struct pci_bus *bus, struct device *parent)
 		domain = -1;
 	}
 
-	bus->domain_nr = domain;
+	return domain;
 }
 #endif
 #endif
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 8e3ef72..380d46d 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2127,7 +2127,9 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus,
 	b->sysdata = sysdata;
 	b->ops = ops;
 	b->number = b->busn_res.start = bus;
-	pci_bus_assign_domain_nr(b, parent);
+#ifdef CONFIG_PCI_DOMAINS_GENERIC
+	b->domain_nr = pci_bus_find_domain_nr(b, parent);
+#endif
 	b2 = pci_find_bus(pci_domain_nr(b), bus);
 	if (b2) {
 		/* If we already got to this bus through a different bridge, ignore it */
diff --git a/include/linux/pci.h b/include/linux/pci.h
index ce03d65..48839e8 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1390,12 +1390,7 @@ static inline int pci_domain_nr(struct pci_bus *bus)
 {
 	return bus->domain_nr;
 }
-void pci_bus_assign_domain_nr(struct pci_bus *bus, struct device *parent);
-#else
-static inline void pci_bus_assign_domain_nr(struct pci_bus *bus,
-					struct device *parent)
-{
-}
+int pci_bus_find_domain_nr(struct pci_bus *bus, struct device *parent);
 #endif
 
 /* some architectures require additional setup to direct VGA traffic */
-- 
2.7.4

From d6d45ae1d58658111d5e838c41b9ed4729bbb81e Mon Sep 17 00:00:00 2001
From: Tomasz Nowicki <tn@semihalf.com>
Date: Fri, 10 Jun 2016 21:55:15 +0200
Subject: [PATCH 07/11] PCI: Factor DT specific pci_bus_find_domain_nr() code
 out

pci_bus_find_domain_nr() retrieves the host bridge domain number in a DT
specific way. Factor our pci_bus_find_domain_nr() in a separate DT
function (ie of_pci_bus_find_domain_nr()) so that DT code is self
contained, paving the way for retrieving domain number in
pci_bus_find_domain_nr() with additional firmware methods (ie ACPI).

Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
---
 drivers/pci/pci.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index b9a7833..97f7cd4 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -4941,7 +4941,7 @@ int pci_get_new_domain_nr(void)
 }
 
 #ifdef CONFIG_PCI_DOMAINS_GENERIC
-int pci_bus_find_domain_nr(struct pci_bus *bus, struct device *parent)
+static int of_pci_bus_find_domain_nr(struct device *parent)
 {
 	static int use_dt_domains = -1;
 	int domain = -1;
@@ -4987,6 +4987,11 @@ int pci_bus_find_domain_nr(struct pci_bus *bus, struct device *parent)
 
 	return domain;
 }
+
+int pci_bus_find_domain_nr(struct pci_bus *bus, struct device *parent)
+{
+	return of_pci_bus_find_domain_nr(parent);
+}
 #endif
 #endif
 
-- 
2.7.4

From 92d59511fd365d3c0c31d074b5e96cf48c58f68b Mon Sep 17 00:00:00 2001
From: Peter Robinson <pbrobinson@gmail.com>
Date: Thu, 30 Jun 2016 16:56:24 +0100
Subject: [PATCH 08/11] ARM64/PCI: Add ACPI hook to assign domain number

PCI core code provides a config option (CONFIG_PCI_DOMAINS_GENERIC)
that allows assigning the PCI bus domain number generically by
relying on device tree bindings, and falling back to a simple counter
when the respective DT properties (ie "linux,pci-domain") are not
specified in the host bridge device tree node.

In a similar way, when a system is booted through ACPI, architectures
that are selecting CONFIG_PCI_DOMAINS_GENERIC (ie ARM64) require kernel
hooks to retrieve the domain number so that the PCI bus domain number
set-up can be handled seamlessly with DT and ACPI in generic core code
when CONFIG_PCI_DOMAINS_GENERIC is selected.

Since currently it is not possible to retrieve a pointer to the PCI
host bridge ACPI device backing the host bridge from core PCI code
(which would allow retrieving the domain number in an arch agnostic
way through the ACPI _SEG method), an arch specific ACPI hook has to
be declared and implemented by all arches that rely on
CONFIG_PCI_DOMAINS_GENERIC to retrieve the domain number and set it
up in core PCI code.

For the aforementioned reasons, introduce acpi_pci_bus_find_domain_nr()
hook to retrieve the domain number on a per-arch basis when the system
boots through ACPI. ARM64 dummy implementation of the same is provided
in first place in preparation for ARM64 ACPI based PCI host controller
driver.

acpi_pci_bus_find_domain_nr() is called from generic
pci_bus_find_domain_nr() as an ACPI option to DT domain assignment.

Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
---
 arch/arm64/kernel/pci.c | 7 +++++++
 drivers/pci/pci.c       | 4 +++-
 include/linux/pci.h     | 7 +++++++
 3 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c
index 3c4e308..d5d3d26 100644
--- a/arch/arm64/kernel/pci.c
+++ b/arch/arm64/kernel/pci.c
@@ -17,6 +17,7 @@
 #include <linux/mm.h>
 #include <linux/of_pci.h>
 #include <linux/of_platform.h>
+#include <linux/pci.h>
 #include <linux/slab.h>
 
 /*
@@ -85,6 +86,12 @@ EXPORT_SYMBOL(pcibus_to_node);
 #endif
 
 #ifdef CONFIG_ACPI
+
+int acpi_pci_bus_find_domain_nr(struct pci_bus *bus)
+{
+	return 0;
+}
+
 /* Root bridge scanning */
 struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root)
 {
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 97f7cd4..4834cee 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -7,6 +7,7 @@
  *	Copyright 1997 -- 2000 Martin Mares <mj@ucw.cz>
  */
 
+#include <linux/acpi.h>
 #include <linux/kernel.h>
 #include <linux/delay.h>
 #include <linux/init.h>
@@ -4990,7 +4991,8 @@ static int of_pci_bus_find_domain_nr(struct device *parent)
 
 int pci_bus_find_domain_nr(struct pci_bus *bus, struct device *parent)
 {
-	return of_pci_bus_find_domain_nr(parent);
+	return acpi_disabled ? of_pci_bus_find_domain_nr(parent) :
+			       acpi_pci_bus_find_domain_nr(bus);
 }
 #endif
 #endif
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 48839e8..49ba8af 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1390,6 +1390,13 @@ static inline int pci_domain_nr(struct pci_bus *bus)
 {
 	return bus->domain_nr;
 }
+/* Arch specific ACPI hook to set-up domain number */
+#ifdef CONFIG_ACPI
+int acpi_pci_bus_find_domain_nr(struct pci_bus *bus);
+#else
+static inline int acpi_pci_bus_find_domain_nr(struct pci_bus *bus)
+{ return 0; }
+#endif
 int pci_bus_find_domain_nr(struct pci_bus *bus, struct device *parent);
 #endif
 
-- 
2.7.4

From bb06753d2e163d8100a017f06a6d9dd195d68a76 Mon Sep 17 00:00:00 2001
From: Tomasz Nowicki <tn@semihalf.com>
Date: Fri, 10 Jun 2016 21:55:17 +0200
Subject: [PATCH 09/11] ARM64/PCI: ACPI support for legacy IRQs parsing and
 consolidation with DT code

To enable PCI legacy IRQs on platforms booting with ACPI, arch code
should include ACPI specific callbacks that parse and set-up the
device IRQ number, equivalent to the DT boot path. Owing to the current
ACPI core scan handlers implementation, ACPI PCI legacy IRQs bindings
cannot be parsed at device add time, since that would trigger ACPI scan
handlers ordering issues depending on how the ACPI tables are defined.

To solve this problem and consolidate FW PCI legacy IRQs parsing in
one single pcibios callback (pending final removal), this patch moves
DT PCI IRQ parsing to the pcibios_alloc_irq() callback (called by
PCI core code at device probe time) and adds ACPI PCI legacy IRQs
parsing to the same callback too, so that FW PCI legacy IRQs parsing
is confined in one single arch callback that can be easily removed
when code parsing PCI legacy IRQs is consolidated and moved to core
PCI code.

Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
Suggested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
---
 arch/arm64/kernel/pci.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c
index d5d3d26..b3b8a2c 100644
--- a/arch/arm64/kernel/pci.c
+++ b/arch/arm64/kernel/pci.c
@@ -51,11 +51,16 @@ int pcibios_enable_device(struct pci_dev *dev, int mask)
 }
 
 /*
- * Try to assign the IRQ number from DT when adding a new device
+ * Try to assign the IRQ number when probing a new device
  */
-int pcibios_add_device(struct pci_dev *dev)
+int pcibios_alloc_irq(struct pci_dev *dev)
 {
-	dev->irq = of_irq_parse_and_map_pci(dev, 0, 0);
+	if (acpi_disabled)
+		dev->irq = of_irq_parse_and_map_pci(dev, 0, 0);
+#ifdef CONFIG_ACPI
+	else
+		return acpi_pci_irq_enable(dev);
+#endif
 
 	return 0;
 }
-- 
2.7.4

From b6e298840f532192a589f8ade128dec3fef3a4c6 Mon Sep 17 00:00:00 2001
From: Tomasz Nowicki <tn@semihalf.com>
Date: Fri, 10 Jun 2016 21:55:18 +0200
Subject: [PATCH 10/11] ARM64/PCI: Implement ACPI low-level calls to access
 PCI_Config region from AML

ACPI spec6.1 - chapter: 5.5.2.4 defines OperationRegion (Declare Operation
Region). Following the spec: " [...] An Operation Region is a specific
region of operation within an address space that is declared as a subset
of the entire address space using a starting address (offset) and a length.
Control methods must have exclusive access to any address accessed via
fields declared in Operation Regions. [...]".

OperationRegion allows to declare various of operation region address space
identifiers including PCI_Config. PCI_Config is meant to access PCI
configuration space from the ASL. So every time ASL opcode operates
on PCI_Config space region, ASL interpreter dispatches accesses to OS
low-level calls - raw_pci_write() and raw_pci_read() for Linux - so-called
ACPI RAW accessors.

In order to support PCI_Config operation region, implement mentioned
raw_pci_write() and raw_pci_read() calls so they find associated bus
and call read/write ops.

Waiting for clarification in the ACPI specifications in relation
to PCI_Config space handling before PCI bus enumeration is completed,
current code does not support PCI_Config region accesses before PCI bus
enumeration whilst providing full AML PCI_Config access availability
when the PCI bus enumeration is completed by the kernel so that
RAW accessors can look-up PCI operations through the struct pci_bus
associated with a PCI bus.

Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
Signed-off-by: Jayachandran C <jchandra@broadcom.com>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
---
 arch/arm64/kernel/pci.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c
index b3b8a2c..328f857 100644
--- a/arch/arm64/kernel/pci.c
+++ b/arch/arm64/kernel/pci.c
@@ -71,13 +71,21 @@ int pcibios_alloc_irq(struct pci_dev *dev)
 int raw_pci_read(unsigned int domain, unsigned int bus,
 		  unsigned int devfn, int reg, int len, u32 *val)
 {
-	return -ENXIO;
+	struct pci_bus *b = pci_find_bus(domain, bus);
+
+	if (!b)
+		return PCIBIOS_DEVICE_NOT_FOUND;
+	return b->ops->read(b, devfn, reg, len, val);
 }
 
 int raw_pci_write(unsigned int domain, unsigned int bus,
 		unsigned int devfn, int reg, int len, u32 val)
 {
-	return -ENXIO;
+	struct pci_bus *b = pci_find_bus(domain, bus);
+
+	if (!b)
+		return PCIBIOS_DEVICE_NOT_FOUND;
+	return b->ops->write(b, devfn, reg, len, val);
 }
 
 #ifdef CONFIG_NUMA
-- 
2.7.4

From 3b8cff3fa89ba3ef6f1cf09a0667aa470b7fad0b Mon Sep 17 00:00:00 2001
From: Tomasz Nowicki <tn@semihalf.com>
Date: Fri, 10 Jun 2016 21:55:19 +0200
Subject: [PATCH 11/11] ARM64/PCI: Support for ACPI based PCI host controller

Implement pci_acpi_scan_root and other arch-specific call so that ARM64
can start using ACPI to setup and enumerate PCI buses.

Prior to buses enumeration the pci_acpi_scan_root() implementation looks
for configuration space start address (obtained through ACPI _CBA method or
MCFG interface). If succeed, it uses ECAM library to create new mapping.
Then it attaches generic ECAM ops (pci_generic_ecam_ops) which are used
for accessing configuration space later on.

On ARM64, we need to use generic domains (CONFIG_PCI_DOMAINS_GENERIC).
In order to achieve that for ACPI case implement
acpi_pci_bus_find_domain_nr() body so that it retrieves pci_config_window
structure from bus sysdata and eventually gets domain number from
acpi_pci_root structure.

ACPI requires to run acpi_pci_{add|remove}_bus while new PCI bus is created.
This allows to do some ACPI-specific additional configuration, like
PCI hotplug slot enumeration. In order to fulfill these requirements,
we implement arch-specific pcibios_{add|remove}_bus calls
and call acpi_pci_{add|remove}_bus from there.

Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
Signed-off-by: Jayachandran C <jchandra@broadcom.com>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
---
 arch/arm64/Kconfig      |   2 +
 arch/arm64/kernel/pci.c | 116 ++++++++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 115 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 5a0a691..4806cde 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -3,6 +3,7 @@ config ARM64
 	select ACPI_CCA_REQUIRED if ACPI
 	select ACPI_GENERIC_GSI if ACPI
 	select ACPI_REDUCED_HARDWARE_ONLY if ACPI
+	select ACPI_MCFG if ACPI
 	select ARCH_HAS_DEVMEM_IS_ALLOWED
 	select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
 	select ARCH_HAS_ELF_RANDOMIZE
@@ -96,6 +97,7 @@ config ARM64
 	select OF_EARLY_FLATTREE
 	select OF_NUMA if NUMA && OF
 	select OF_RESERVED_MEM
+	select PCI_ECAM if ACPI
 	select PERF_USE_VMALLOC
 	select POWER_RESET
 	select POWER_SUPPLY
diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c
index 328f857..94cd43c 100644
--- a/arch/arm64/kernel/pci.c
+++ b/arch/arm64/kernel/pci.c
@@ -18,6 +18,8 @@
 #include <linux/of_pci.h>
 #include <linux/of_platform.h>
 #include <linux/pci.h>
+#include <linux/pci-acpi.h>
+#include <linux/pci-ecam.h>
 #include <linux/slab.h>
 
 /*
@@ -100,15 +102,123 @@ EXPORT_SYMBOL(pcibus_to_node);
 
 #ifdef CONFIG_ACPI
 
+struct acpi_pci_generic_root_info {
+	struct acpi_pci_root_info	common;
+	struct pci_config_window	*cfg;	/* config space mapping */
+};
+
 int acpi_pci_bus_find_domain_nr(struct pci_bus *bus)
 {
+	struct pci_config_window *cfg = bus->sysdata;
+	struct acpi_device *adev = to_acpi_device(cfg->parent);
+	struct acpi_pci_root *root = acpi_driver_data(adev);
+
+	return root->segment;
+}
+
+int pcibios_root_bridge_prepare(struct pci_host_bridge *bridge)
+{
+	if (!acpi_disabled) {
+		struct pci_config_window *cfg = bridge->bus->sysdata;
+		struct acpi_device *adev = to_acpi_device(cfg->parent);
+		ACPI_COMPANION_SET(&bridge->dev, adev);
+	}
+
 	return 0;
 }
 
-/* Root bridge scanning */
+/*
+ * Lookup the bus range for the domain in MCFG, and set up config space
+ * mapping.
+ */
+static struct pci_config_window *
+pci_acpi_setup_ecam_mapping(struct acpi_pci_root *root)
+{
+	struct resource *bus_res = &root->secondary;
+	u16 seg = root->segment;
+	struct pci_config_window *cfg;
+	struct resource cfgres;
+	unsigned int bsz;
+
+	/* Use address from _CBA if present, otherwise lookup MCFG */
+	if (!root->mcfg_addr)
+		root->mcfg_addr = pci_mcfg_lookup(seg, bus_res);
+
+	if (!root->mcfg_addr) {
+		dev_err(&root->device->dev, "%04x:%pR ECAM region not found\n",
+			seg, bus_res);
+		return NULL;
+	}
+
+	bsz = 1 << pci_generic_ecam_ops.bus_shift;
+	cfgres.start = root->mcfg_addr + bus_res->start * bsz;
+	cfgres.end = cfgres.start + resource_size(bus_res) * bsz - 1;
+	cfgres.flags = IORESOURCE_MEM;
+	cfg = pci_ecam_create(&root->device->dev, &cfgres, bus_res,
+			      &pci_generic_ecam_ops);
+	if (IS_ERR(cfg)) {
+		dev_err(&root->device->dev, "%04x:%pR error %ld mapping ECAM\n",
+			seg, bus_res, PTR_ERR(cfg));
+		return NULL;
+	}
+
+	return cfg;
+}
+
+/* release_info: free resources allocated by init_info */
+static void pci_acpi_generic_release_info(struct acpi_pci_root_info *ci)
+{
+	struct acpi_pci_generic_root_info *ri;
+
+	ri = container_of(ci, struct acpi_pci_generic_root_info, common);
+	pci_ecam_free(ri->cfg);
+	kfree(ri);
+}
+
+static struct acpi_pci_root_ops acpi_pci_root_ops = {
+	.release_info = pci_acpi_generic_release_info,
+};
+
+/* Interface called from ACPI code to setup PCI host controller */
 struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root)
 {
-	/* TODO: Should be revisited when implementing PCI on ACPI */
-	return NULL;
+	int node = acpi_get_node(root->device->handle);
+	struct acpi_pci_generic_root_info *ri;
+	struct pci_bus *bus, *child;
+
+	ri = kzalloc_node(sizeof(*ri), GFP_KERNEL, node);
+	if (!ri)
+		return NULL;
+
+	ri->cfg = pci_acpi_setup_ecam_mapping(root);
+	if (!ri->cfg) {
+		kfree(ri);
+		return NULL;
+	}
+
+	acpi_pci_root_ops.pci_ops = &ri->cfg->ops->pci_ops;
+	bus = acpi_pci_root_create(root, &acpi_pci_root_ops, &ri->common,
+				   ri->cfg);
+	if (!bus)
+		return NULL;
+
+	pci_bus_size_bridges(bus);
+	pci_bus_assign_resources(bus);
+
+	list_for_each_entry(child, &bus->children, node)
+		pcie_bus_configure_settings(child);
+
+	return bus;
+}
+
+void pcibios_add_bus(struct pci_bus *bus)
+{
+	acpi_pci_add_bus(bus);
 }
+
+void pcibios_remove_bus(struct pci_bus *bus)
+{
+	acpi_pci_remove_bus(bus);
+}
+
 #endif
-- 
2.7.4