Thread (17 messages) 17 messages, 4 authors, 2015-04-03
STALE4101d
Revisions (5)
  1. v1 [diff vs current]
  2. v2 [diff vs current]
  3. v3 [diff vs current]
  4. v4 current
  5. v5 [diff vs current]

[PATCH v4 4/9] x86, pci, acpi: Move arch-agnostic MMCONFIG (aka ECAM) and ACPI code out of arch/x86/ directory

From: Tomasz Nowicki <hidden>
Date: 2015-03-11 14:16:12
Also in: linux-acpi, linux-pci, lkml
Subsystem: acpi, pci subsystem, the rest, x86 architecture (32-bit and 64-bit), xen hypervisor interface · Maintainers: "Rafael J. Wysocki", Bjorn Helgaas, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, Juergen Gross, Stefano Stabellini

ECAM standard and MCFG table are architecture independent and it makes
sense to share common code across all architectures. Both are going to
corresponding files - ecam.c and mcfg.c

While we are here, rename pci_parse_mcfg to acpi_parse_mcfg.
We already have acpi_parse_mcfg prototype which is used nowhere.
At the same time, we need pci_parse_mcfg been global so acpi_parse_mcfg
can be used perfectly here.

Signed-off-by: Tomasz Nowicki <redacted>
---
 arch/x86/Kconfig               |   3 +
 arch/x86/include/asm/pci_x86.h |  33 -----
 arch/x86/pci/acpi.c            |   1 +
 arch/x86/pci/mmconfig-shared.c | 296 +----------------------------------------
 arch/x86/pci/mmconfig_32.c     |   1 +
 arch/x86/pci/mmconfig_64.c     |   1 +
 arch/x86/pci/numachip.c        |   1 +
 drivers/acpi/Makefile          |   1 +
 drivers/acpi/mcfg.c            |  81 +++++++++++
 drivers/pci/Kconfig            |   7 +
 drivers/pci/Makefile           |   5 +
 drivers/pci/ecam.c             | 245 ++++++++++++++++++++++++++++++++++
 drivers/xen/pci.c              |   1 +
 include/linux/ecam.h           |  51 +++++++
 14 files changed, 401 insertions(+), 326 deletions(-)
 create mode 100644 drivers/acpi/mcfg.c
 create mode 100644 drivers/pci/ecam.c
 create mode 100644 include/linux/ecam.h
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index c2fb8a8..aa451bf 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -141,6 +141,7 @@ config X86
 	select ACPI_LEGACY_TABLES_LOOKUP if ACPI
 	select X86_FEATURE_NAMES if PROC_FS
 	select SRCU
+	select HAVE_PCI_ECAM
 
 config INSTRUCTION_DECODER
 	def_bool y
@@ -2276,6 +2277,7 @@ config PCI_DIRECT
 
 config PCI_MMCONFIG
 	def_bool y
+	select PCI_ECAM
 	depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
 
 config PCI_OLPC
@@ -2293,6 +2295,7 @@ config PCI_DOMAINS
 
 config PCI_MMCONFIG
 	bool "Support mmconfig PCI config space access"
+	select PCI_ECAM
 	depends on X86_64 && PCI && ACPI
 
 config PCI_CNB20LE_QUIRK
diff --git a/arch/x86/include/asm/pci_x86.h b/arch/x86/include/asm/pci_x86.h
index c57c225..e8a237f 100644
--- a/arch/x86/include/asm/pci_x86.h
+++ b/arch/x86/include/asm/pci_x86.h
@@ -122,41 +122,8 @@ extern int pci_legacy_init(void);
 extern void pcibios_fixup_irqs(void);
 
 /* pci-mmconfig.c */
-
-/* "PCI MMCONFIG %04x [bus %02x-%02x]" */
-#define PCI_MMCFG_RESOURCE_NAME_LEN (22 + 4 + 2 + 2)
-
-struct pci_mmcfg_region {
-	struct list_head list;
-	struct resource res;
-	u64 address;
-	char __iomem *virt;
-	u16 segment;
-	u8 start_bus;
-	u8 end_bus;
-	char name[PCI_MMCFG_RESOURCE_NAME_LEN];
-};
-
-struct pci_mmcfg_mmio_ops {
-	u32 (*read)(int len, void __iomem *addr);
-	void (*write)(int len, void __iomem *addr, u32 value);
-};
-
-extern int __init pci_mmcfg_arch_init(void);
-extern void __init pci_mmcfg_arch_free(void);
-extern int pci_mmcfg_arch_map(struct pci_mmcfg_region *cfg);
-extern void pci_mmcfg_arch_unmap(struct pci_mmcfg_region *cfg);
 extern int pci_mmconfig_insert(struct device *dev, u16 seg, u8 start, u8 end,
 			       phys_addr_t addr);
-extern int pci_mmconfig_delete(u16 seg, u8 start, u8 end);
-extern struct pci_mmcfg_region *pci_mmconfig_lookup(int segment, int bus);
-extern u32 pci_mmio_read(int len, void __iomem *addr);
-extern void pci_mmio_write(int len, void __iomem *addr, u32 value);
-extern void pci_mmconfig_register_mmio(struct pci_mmcfg_mmio_ops *ops);
-
-extern struct list_head pci_mmcfg_list;
-
-#define PCI_MMCFG_BUS_OFFSET(bus)      ((bus) << 20)
 
 /*
  * AMD Fam10h CPUs are buggy, and cannot access MMIO config space
diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c
index 6ac2738..5dfccef 100644
--- a/arch/x86/pci/acpi.c
+++ b/arch/x86/pci/acpi.c
@@ -4,6 +4,7 @@
 #include <linux/irq.h>
 #include <linux/dmi.h>
 #include <linux/slab.h>
+#include <linux/ecam.h>
 #include <asm/numa.h>
 #include <asm/pci_x86.h>
 
diff --git a/arch/x86/pci/mmconfig-shared.c b/arch/x86/pci/mmconfig-shared.c
index 685cd4c..5064302 100644
--- a/arch/x86/pci/mmconfig-shared.c
+++ b/arch/x86/pci/mmconfig-shared.c
@@ -18,6 +18,7 @@
 #include <linux/slab.h>
 #include <linux/mutex.h>
 #include <linux/rculist.h>
+#include <linux/ecam.h>
 #include <asm/e820.h>
 #include <asm/pci_x86.h>
 #include <asm/acpi.h>
@@ -27,52 +28,6 @@
 /* Indicate if the mmcfg resources have been placed into the resource table. */
 static bool pci_mmcfg_running_state;
 static bool pci_mmcfg_arch_init_failed;
-static DEFINE_MUTEX(pci_mmcfg_lock);
-
-LIST_HEAD(pci_mmcfg_list);
-
-static u32
-pci_mmconfig_generic_read(int len, void __iomem *addr)
-{
-	u32 data = 0;
-
-	switch (len) {
-	case 1:
-		data = readb(addr);
-		break;
-	case 2:
-		data = readw(addr);
-		break;
-	case 4:
-		data = readl(addr);
-		break;
-	}
-
-	return data;
-}
-
-static void
-pci_mmconfig_generic_write(int len, void __iomem *addr, u32 value)
-{
-	switch (len) {
-	case 1:
-		writeb(value, addr);
-		break;
-	case 2:
-		writew(value, addr);
-		break;
-	case 4:
-		writel(value, addr);
-		break;
-	}
-}
-
-static struct pci_mmcfg_mmio_ops pci_mmcfg_mmio_default = {
-	.read = pci_mmconfig_generic_read,
-	.write = pci_mmconfig_generic_write,
-};
-
-static struct pci_mmcfg_mmio_ops *pci_mmcfg_mmio = &pci_mmcfg_mmio_default;
 
 static u32
 pci_mmconfig_amd_read(int len, void __iomem *addr)
@@ -115,128 +70,6 @@ static struct pci_mmcfg_mmio_ops pci_mmcfg_mmio_amd_fam10h = {
 	.write = pci_mmconfig_amd_write,
 };
 
-void
-pci_mmconfig_register_mmio(struct pci_mmcfg_mmio_ops *ops)
-{
-	pci_mmcfg_mmio = ops;
-}
-
-u32
-pci_mmio_read(int len, void __iomem *addr)
-{
-	if (!pci_mmcfg_mmio) {
-		pr_err("PCI config space has no accessors !");
-		return 0;
-	}
-
-	return pci_mmcfg_mmio->read(len, addr);
-}
-
-void
-pci_mmio_write(int len, void __iomem *addr, u32 value)
-{
-	if (!pci_mmcfg_mmio) {
-		pr_err("PCI config space has no accessors !");
-		return;
-	}
-
-	pci_mmcfg_mmio->write(len, addr, value);
-}
-
-static void __init pci_mmconfig_remove(struct pci_mmcfg_region *cfg)
-{
-	if (cfg->res.parent)
-		release_resource(&cfg->res);
-	list_del(&cfg->list);
-	kfree(cfg);
-}
-
-static void __init free_all_mmcfg(void)
-{
-	struct pci_mmcfg_region *cfg, *tmp;
-
-	pci_mmcfg_arch_free();
-	list_for_each_entry_safe(cfg, tmp, &pci_mmcfg_list, list)
-		pci_mmconfig_remove(cfg);
-}
-
-static void list_add_sorted(struct pci_mmcfg_region *new)
-{
-	struct pci_mmcfg_region *cfg;
-
-	/* keep list sorted by segment and starting bus number */
-	list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list) {
-		if (cfg->segment > new->segment ||
-		    (cfg->segment == new->segment &&
-		     cfg->start_bus >= new->start_bus)) {
-			list_add_tail_rcu(&new->list, &cfg->list);
-			return;
-		}
-	}
-	list_add_tail_rcu(&new->list, &pci_mmcfg_list);
-}
-
-static struct pci_mmcfg_region *pci_mmconfig_alloc(int segment, int start,
-						   int end, u64 addr)
-{
-	struct pci_mmcfg_region *new;
-	struct resource *res;
-
-	if (addr == 0)
-		return NULL;
-
-	new = kzalloc(sizeof(*new), GFP_KERNEL);
-	if (!new)
-		return NULL;
-
-	new->address = addr;
-	new->segment = segment;
-	new->start_bus = start;
-	new->end_bus = end;
-
-	res = &new->res;
-	res->start = addr + PCI_MMCFG_BUS_OFFSET(start);
-	res->end = addr + PCI_MMCFG_BUS_OFFSET(end + 1) - 1;
-	res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
-	snprintf(new->name, PCI_MMCFG_RESOURCE_NAME_LEN,
-		 "PCI MMCONFIG %04x [bus %02x-%02x]", segment, start, end);
-	res->name = new->name;
-
-	return new;
-}
-
-static struct pci_mmcfg_region *__init pci_mmconfig_add(int segment, int start,
-							int end, u64 addr)
-{
-	struct pci_mmcfg_region *new;
-
-	new = pci_mmconfig_alloc(segment, start, end, addr);
-	if (new) {
-		mutex_lock(&pci_mmcfg_lock);
-		list_add_sorted(new);
-		mutex_unlock(&pci_mmcfg_lock);
-
-		pr_info(PREFIX
-		       "MMCONFIG for domain %04x [bus %02x-%02x] at %pR "
-		       "(base %#lx)\n",
-		       segment, start, end, &new->res, (unsigned long)addr);
-	}
-
-	return new;
-}
-
-struct pci_mmcfg_region *pci_mmconfig_lookup(int segment, int bus)
-{
-	struct pci_mmcfg_region *cfg;
-
-	list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list)
-		if (cfg->segment == segment &&
-		    cfg->start_bus <= bus && bus <= cfg->end_bus)
-			return cfg;
-
-	return NULL;
-}
-
 static const char *__init pci_mmcfg_e7520(void)
 {
 	u32 win;
@@ -657,73 +490,6 @@ static void __init pci_mmcfg_reject_broken(int early)
 	}
 }
 
-static int __init acpi_mcfg_check_entry(struct acpi_table_mcfg *mcfg,
-					struct acpi_mcfg_allocation *cfg)
-{
-	int year;
-
-	if (cfg->address < 0xFFFFFFFF)
-		return 0;
-
-	if (!strncmp(mcfg->header.oem_id, "SGI", 3))
-		return 0;
-
-	if (mcfg->header.revision >= 1) {
-		if (dmi_get_date(DMI_BIOS_DATE, &year, NULL, NULL) &&
-		    year >= 2010)
-			return 0;
-	}
-
-	pr_err(PREFIX "MCFG region for %04x [bus %02x-%02x] at %#llx "
-	       "is above 4GB, ignored\n", cfg->pci_segment,
-	       cfg->start_bus_number, cfg->end_bus_number, cfg->address);
-	return -EINVAL;
-}
-
-static int __init pci_parse_mcfg(struct acpi_table_header *header)
-{
-	struct acpi_table_mcfg *mcfg;
-	struct acpi_mcfg_allocation *cfg_table, *cfg;
-	unsigned long i;
-	int entries;
-
-	if (!header)
-		return -EINVAL;
-
-	mcfg = (struct acpi_table_mcfg *)header;
-
-	/* how many config structures do we have */
-	free_all_mmcfg();
-	entries = 0;
-	i = header->length - sizeof(struct acpi_table_mcfg);
-	while (i >= sizeof(struct acpi_mcfg_allocation)) {
-		entries++;
-		i -= sizeof(struct acpi_mcfg_allocation);
-	}
-	if (entries == 0) {
-		pr_err(PREFIX "MMCONFIG has no entries\n");
-		return -ENODEV;
-	}
-
-	cfg_table = (struct acpi_mcfg_allocation *) &mcfg[1];
-	for (i = 0; i < entries; i++) {
-		cfg = &cfg_table[i];
-		if (acpi_mcfg_check_entry(mcfg, cfg)) {
-			free_all_mmcfg();
-			return -ENODEV;
-		}
-
-		if (pci_mmconfig_add(cfg->pci_segment, cfg->start_bus_number,
-				   cfg->end_bus_number, cfg->address) == NULL) {
-			pr_warn(PREFIX "no memory for MCFG entries\n");
-			free_all_mmcfg();
-			return -ENOMEM;
-		}
-	}
-
-	return 0;
-}
-
 #ifdef CONFIG_ACPI_APEI
 extern int (*arch_apei_filter_addr)(int (*func)(__u64 start, __u64 size,
 				     void *data), void *data);
@@ -782,7 +548,7 @@ void __init pci_mmcfg_early_init(void)
 		if (pci_mmcfg_check_hostbridge())
 			known_bridge = 1;
 		else
-			acpi_sfi_table_parse(ACPI_SIG_MCFG, pci_parse_mcfg);
+			acpi_sfi_table_parse(ACPI_SIG_MCFG, acpi_parse_mcfg);
 		__pci_mmcfg_init(1);
 
 		set_apei_filter();
@@ -800,7 +566,7 @@ void __init pci_mmcfg_late_init(void)
 
 	/* MMCONFIG hasn't been enabled yet, try again */
 	if (pci_probe & PCI_PROBE_MASK & ~PCI_PROBE_MMCONF) {
-		acpi_sfi_table_parse(ACPI_SIG_MCFG, pci_parse_mcfg);
+		acpi_sfi_table_parse(ACPI_SIG_MCFG, acpi_parse_mcfg);
 		__pci_mmcfg_init(0);
 	}
 }
@@ -834,39 +600,6 @@ static int __init pci_mmcfg_late_insert_resources(void)
  */
 late_initcall(pci_mmcfg_late_insert_resources);
 
-static int pci_mmconfig_inject(struct pci_mmcfg_region *cfg)
-{
-	struct pci_mmcfg_region *cfg_conflict;
-	int err = 0;
-
-	mutex_lock(&pci_mmcfg_lock);
-	cfg_conflict = pci_mmconfig_lookup(cfg->segment, cfg->start_bus);
-	if (cfg_conflict) {
-		if (cfg_conflict->end_bus < cfg->end_bus)
-			pr_info(FW_INFO "MMCONFIG for "
-				"domain %04x [bus %02x-%02x] "
-				"only partially covers this bridge\n",
-				cfg_conflict->segment, cfg_conflict->start_bus,
-				cfg_conflict->end_bus);
-		err = -EEXIST;
-		goto out;
-	}
-
-	if (pci_mmcfg_arch_map(cfg)) {
-		pr_warn("fail to map MMCONFIG %pR.\n", &cfg->res);
-		err = -ENOMEM;
-		goto out;
-	} else {
-		list_add_sorted(cfg);
-		pr_info("MMCONFIG at %pR (base %#lx)\n",
-			&cfg->res, (unsigned long)cfg->address);
-
-	}
-out:
-	mutex_unlock(&pci_mmcfg_lock);
-	return err;
-}
-
 /* Add MMCFG information for host bridges */
 int pci_mmconfig_insert(struct device *dev, u16 seg, u8 start, u8 end,
 			phys_addr_t addr)
@@ -915,26 +648,3 @@ error:
 	kfree(cfg);
 	return rc;
 }
-
-/* Delete MMCFG information for host bridges */
-int pci_mmconfig_delete(u16 seg, u8 start, u8 end)
-{
-	struct pci_mmcfg_region *cfg;
-
-	mutex_lock(&pci_mmcfg_lock);
-	list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list)
-		if (cfg->segment == seg && cfg->start_bus == start &&
-		    cfg->end_bus == end) {
-			list_del_rcu(&cfg->list);
-			synchronize_rcu();
-			pci_mmcfg_arch_unmap(cfg);
-			if (cfg->res.parent)
-				release_resource(&cfg->res);
-			mutex_unlock(&pci_mmcfg_lock);
-			kfree(cfg);
-			return 0;
-		}
-	mutex_unlock(&pci_mmcfg_lock);
-
-	return -ENOENT;
-}
diff --git a/arch/x86/pci/mmconfig_32.c b/arch/x86/pci/mmconfig_32.c
index 4b3d025..5cf6291 100644
--- a/arch/x86/pci/mmconfig_32.c
+++ b/arch/x86/pci/mmconfig_32.c
@@ -12,6 +12,7 @@
 #include <linux/pci.h>
 #include <linux/init.h>
 #include <linux/rcupdate.h>
+#include <linux/ecam.h>
 #include <asm/e820.h>
 #include <asm/pci_x86.h>
 
diff --git a/arch/x86/pci/mmconfig_64.c b/arch/x86/pci/mmconfig_64.c
index 032593d..b62ff18 100644
--- a/arch/x86/pci/mmconfig_64.c
+++ b/arch/x86/pci/mmconfig_64.c
@@ -10,6 +10,7 @@
 #include <linux/acpi.h>
 #include <linux/bitmap.h>
 #include <linux/rcupdate.h>
+#include <linux/ecam.h>
 #include <asm/e820.h>
 #include <asm/pci_x86.h>
 
diff --git a/arch/x86/pci/numachip.c b/arch/x86/pci/numachip.c
index 5047e9b..01868b6 100644
--- a/arch/x86/pci/numachip.c
+++ b/arch/x86/pci/numachip.c
@@ -13,6 +13,7 @@
  *
  */
 
+#include <linux/ecam.h>
 #include <linux/pci.h>
 #include <asm/pci_x86.h>
 
diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 623b117..39498a1 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -67,6 +67,7 @@ obj-$(CONFIG_ACPI_BUTTON)	+= button.o
 obj-$(CONFIG_ACPI_FAN)		+= fan.o
 obj-$(CONFIG_ACPI_VIDEO)	+= video.o
 obj-$(CONFIG_ACPI_PCI_SLOT)	+= pci_slot.o
+obj-$(CONFIG_PCI_MMCONFIG)	+= mcfg.o
 obj-$(CONFIG_ACPI_PROCESSOR)	+= processor.o
 obj-y				+= container.o
 obj-$(CONFIG_ACPI_THERMAL)	+= thermal.o
diff --git a/drivers/acpi/mcfg.c b/drivers/acpi/mcfg.c
new file mode 100644
index 0000000..a2e2326
--- /dev/null
+++ b/drivers/acpi/mcfg.c
@@ -0,0 +1,81 @@
+/*
+ * MCFG ACPI table parser.
+ *
+ * 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.
+ *
+ */
+
+#include <linux/acpi.h>
+#include <linux/dmi.h>
+#include <linux/ecam.h>
+
+#define	PREFIX	"MCFG: "
+
+static int __init acpi_mcfg_check_entry(struct acpi_table_mcfg *mcfg,
+					struct acpi_mcfg_allocation *cfg)
+{
+	int year;
+
+	if (cfg->address < 0xFFFFFFFF)
+		return 0;
+
+	if (!strncmp(mcfg->header.oem_id, "SGI", 3))
+		return 0;
+
+	if (mcfg->header.revision >= 1) {
+		if (dmi_get_date(DMI_BIOS_DATE, &year, NULL, NULL) &&
+		    year >= 2010)
+			return 0;
+	}
+
+	pr_err(PREFIX "MCFG region for %04x [bus %02x-%02x] at %#llx "
+	       "is above 4GB, ignored\n", cfg->pci_segment,
+	       cfg->start_bus_number, cfg->end_bus_number, cfg->address);
+	return -EINVAL;
+}
+
+int __init acpi_parse_mcfg(struct acpi_table_header *header)
+{
+	struct acpi_table_mcfg *mcfg;
+	struct acpi_mcfg_allocation *cfg_table, *cfg;
+	unsigned long i;
+	int entries;
+
+	if (!header)
+		return -EINVAL;
+
+	mcfg = (struct acpi_table_mcfg *)header;
+
+	/* how many config structures do we have */
+	free_all_mmcfg();
+	entries = 0;
+	i = header->length - sizeof(struct acpi_table_mcfg);
+	while (i >= sizeof(struct acpi_mcfg_allocation)) {
+		entries++;
+		i -= sizeof(struct acpi_mcfg_allocation);
+	}
+	if (entries == 0) {
+		pr_err(PREFIX "MCFG table has no entries\n");
+		return -ENODEV;
+	}
+
+	cfg_table = (struct acpi_mcfg_allocation *) &mcfg[1];
+	for (i = 0; i < entries; i++) {
+		cfg = &cfg_table[i];
+		if (acpi_mcfg_check_entry(mcfg, cfg)) {
+			free_all_mmcfg();
+			return -ENODEV;
+		}
+
+		if (pci_mmconfig_add(cfg->pci_segment, cfg->start_bus_number,
+				   cfg->end_bus_number, cfg->address) == NULL) {
+			pr_warn(PREFIX "no memory for MCFG entries\n");
+			free_all_mmcfg();
+			return -ENOMEM;
+		}
+	}
+
+	return 0;
+}
diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
index 7a8f1c5..90a5fb9 100644
--- a/drivers/pci/Kconfig
+++ b/drivers/pci/Kconfig
@@ -22,6 +22,13 @@ config PCI_MSI_IRQ_DOMAIN
 	depends on PCI_MSI
 	select GENERIC_MSI_IRQ_DOMAIN
 
+config PCI_ECAM
+	bool "Enhanced Configuration Access Mechanism (ECAM)"
+	depends on PCI && HAVE_PCI_ECAM
+
+config HAVE_PCI_ECAM
+	bool
+
 config PCI_DEBUG
 	bool "PCI Debugging"
 	depends on PCI && DEBUG_KERNEL
diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile
index 73e4af4..ce7b630 100644
--- a/drivers/pci/Makefile
+++ b/drivers/pci/Makefile
@@ -41,6 +41,11 @@ obj-$(CONFIG_SPARC_LEON) += setup-irq.o
 obj-$(CONFIG_M68K) += setup-irq.o
 
 #
+# Enhanced Configuration Access Mechanism (ECAM)
+#
+obj-$(CONFIG_PCI_ECAM)	+= ecam.o
+
+#
 # ACPI Related PCI FW Functions
 # ACPI _DSM provided firmware instance and string name
 #
diff --git a/drivers/pci/ecam.c b/drivers/pci/ecam.c
new file mode 100644
index 0000000..c588234
--- /dev/null
+++ b/drivers/pci/ecam.c
@@ -0,0 +1,245 @@
+/*
+ * Arch agnostic direct PCI config space access via
+ * ECAM (Enhanced Configuration Access Mechanism)
+ *
+ * Per-architecture code takes care of the mappings, region validation and
+ * accesses themselves.
+ *
+ * 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.
+ *
+ */
+
+#include <linux/mutex.h>
+#include <linux/rculist.h>
+#include <linux/ecam.h>
+
+#include <asm/io.h>
+
+#define PREFIX "PCI: "
+
+static DEFINE_MUTEX(pci_mmcfg_lock);
+
+LIST_HEAD(pci_mmcfg_list);
+
+static u32
+pci_mmconfig_generic_read(int len, void __iomem *addr)
+{
+	u32 data = 0;
+
+	switch (len) {
+	case 1:
+		data = readb(addr);
+		break;
+	case 2:
+		data = readw(addr);
+		break;
+	case 4:
+		data = readl(addr);
+		break;
+	}
+
+	return data;
+}
+
+static void
+pci_mmconfig_generic_write(int len, void __iomem *addr, u32 value)
+{
+	switch (len) {
+	case 1:
+		writeb(value, addr);
+		break;
+	case 2:
+		writew(value, addr);
+		break;
+	case 4:
+		writel(value, addr);
+		break;
+	}
+}
+
+static struct pci_mmcfg_mmio_ops pci_mmcfg_mmio_default = {
+	.read = pci_mmconfig_generic_read,
+	.write = pci_mmconfig_generic_write,
+};
+
+static struct pci_mmcfg_mmio_ops *pci_mmcfg_mmio = &pci_mmcfg_mmio_default;
+
+void
+pci_mmconfig_register_mmio(struct pci_mmcfg_mmio_ops *ops)
+{
+	pci_mmcfg_mmio = ops;
+}
+
+u32
+pci_mmio_read(int len, void __iomem *addr)
+{
+	if (!pci_mmcfg_mmio) {
+		pr_err("PCI config space has no accessors !");
+		return 0;
+	}
+
+	return pci_mmcfg_mmio->read(len, addr);
+}
+
+void
+pci_mmio_write(int len, void __iomem *addr, u32 value)
+{
+	if (!pci_mmcfg_mmio) {
+		pr_err("PCI config space has no accessors !");
+		return;
+	}
+
+	pci_mmcfg_mmio->write(len, addr, value);
+}
+
+static void __init pci_mmconfig_remove(struct pci_mmcfg_region *cfg)
+{
+	if (cfg->res.parent)
+		release_resource(&cfg->res);
+	list_del(&cfg->list);
+	kfree(cfg);
+}
+
+void __init free_all_mmcfg(void)
+{
+	struct pci_mmcfg_region *cfg, *tmp;
+
+	pci_mmcfg_arch_free();
+	list_for_each_entry_safe(cfg, tmp, &pci_mmcfg_list, list)
+		pci_mmconfig_remove(cfg);
+}
+
+void list_add_sorted(struct pci_mmcfg_region *new)
+{
+	struct pci_mmcfg_region *cfg;
+
+	/* keep list sorted by segment and starting bus number */
+	list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list) {
+		if (cfg->segment > new->segment ||
+		    (cfg->segment == new->segment &&
+		     cfg->start_bus >= new->start_bus)) {
+			list_add_tail_rcu(&new->list, &cfg->list);
+			return;
+		}
+	}
+	list_add_tail_rcu(&new->list, &pci_mmcfg_list);
+}
+
+struct pci_mmcfg_region *pci_mmconfig_alloc(int segment, int start,
+					    int end, u64 addr)
+{
+	struct pci_mmcfg_region *new;
+	struct resource *res;
+
+	if (addr == 0)
+		return NULL;
+
+	new = kzalloc(sizeof(*new), GFP_KERNEL);
+	if (!new)
+		return NULL;
+
+	new->address = addr;
+	new->segment = segment;
+	new->start_bus = start;
+	new->end_bus = end;
+
+	res = &new->res;
+	res->start = addr + PCI_MMCFG_BUS_OFFSET(start);
+	res->end = addr + PCI_MMCFG_BUS_OFFSET(end + 1) - 1;
+	res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
+	snprintf(new->name, PCI_MMCFG_RESOURCE_NAME_LEN,
+		 "PCI MMCONFIG %04x [bus %02x-%02x]", segment, start, end);
+	res->name = new->name;
+
+	return new;
+}
+
+struct pci_mmcfg_region *pci_mmconfig_add(int segment, int start,
+					  int end, u64 addr)
+{
+	struct pci_mmcfg_region *new;
+
+	new = pci_mmconfig_alloc(segment, start, end, addr);
+	if (new) {
+		mutex_lock(&pci_mmcfg_lock);
+		list_add_sorted(new);
+		mutex_unlock(&pci_mmcfg_lock);
+
+		pr_info(PREFIX
+		       "MMCONFIG for domain %04x [bus %02x-%02x] at %pR "
+		       "(base %#lx)\n",
+		       segment, start, end, &new->res, (unsigned long)addr);
+	}
+
+	return new;
+}
+
+struct pci_mmcfg_region *pci_mmconfig_lookup(int segment, int bus)
+{
+	struct pci_mmcfg_region *cfg;
+
+	list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list)
+		if (cfg->segment == segment &&
+		    cfg->start_bus <= bus && bus <= cfg->end_bus)
+			return cfg;
+
+	return NULL;
+}
+
+/* Delete MMCFG information for host bridges */
+int pci_mmconfig_delete(u16 seg, u8 start, u8 end)
+{
+	struct pci_mmcfg_region *cfg;
+
+	mutex_lock(&pci_mmcfg_lock);
+	list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list)
+		if (cfg->segment == seg && cfg->start_bus == start &&
+		    cfg->end_bus == end) {
+			list_del_rcu(&cfg->list);
+			synchronize_rcu();
+			pci_mmcfg_arch_unmap(cfg);
+			if (cfg->res.parent)
+				release_resource(&cfg->res);
+			mutex_unlock(&pci_mmcfg_lock);
+			kfree(cfg);
+			return 0;
+		}
+	mutex_unlock(&pci_mmcfg_lock);
+
+	return -ENOENT;
+}
+
+int pci_mmconfig_inject(struct pci_mmcfg_region *cfg)
+{
+	struct pci_mmcfg_region *cfg_conflict;
+	int err = 0;
+
+	mutex_lock(&pci_mmcfg_lock);
+	cfg_conflict = pci_mmconfig_lookup(cfg->segment, cfg->start_bus);
+	if (cfg_conflict) {
+		if (cfg_conflict->end_bus < cfg->end_bus)
+			pr_info(FW_INFO "MMCONFIG for "
+				"domain %04x [bus %02x-%02x] "
+				"only partially covers this bridge\n",
+				cfg_conflict->segment, cfg_conflict->start_bus,
+				cfg_conflict->end_bus);
+		err = -EEXIST;
+		goto out;
+	}
+
+	if (pci_mmcfg_arch_map(cfg)) {
+		pr_warn("fail to map MMCONFIG %pR.\n", &cfg->res);
+		err = -ENOMEM;
+		goto out;
+	} else {
+		list_add_sorted(cfg);
+		pr_info("MMCONFIG at %pR (base %#lx)\n",
+			&cfg->res, (unsigned long)cfg->address);
+
+	}
+out:
+	mutex_unlock(&pci_mmcfg_lock);
+	return err;
+}
diff --git a/drivers/xen/pci.c b/drivers/xen/pci.c
index 95ee430..7a34a72 100644
--- a/drivers/xen/pci.c
+++ b/drivers/xen/pci.c
@@ -19,6 +19,7 @@
 
 #include <linux/pci.h>
 #include <linux/acpi.h>
+#include <linux/ecam.h>
 #include <xen/xen.h>
 #include <xen/interface/physdev.h>
 #include <xen/interface/xen.h>
diff --git a/include/linux/ecam.h b/include/linux/ecam.h
new file mode 100644
index 0000000..2387df5
--- /dev/null
+++ b/include/linux/ecam.h
@@ -0,0 +1,51 @@
+#ifndef __ECAM_H
+#define __ECAM_H
+#ifdef __KERNEL__
+
+#include <linux/types.h>
+#include <linux/acpi.h>
+
+/* "PCI MMCONFIG %04x [bus %02x-%02x]" */
+#define PCI_MMCFG_RESOURCE_NAME_LEN (22 + 4 + 2 + 2)
+
+struct pci_mmcfg_region {
+	struct list_head list;
+	struct resource res;
+	u64 address;
+	char __iomem *virt;
+	u16 segment;
+	u8 start_bus;
+	u8 end_bus;
+	char name[PCI_MMCFG_RESOURCE_NAME_LEN];
+};
+
+struct pci_mmcfg_mmio_ops {
+	u32 (*read)(int len, void __iomem *addr);
+	void (*write)(int len, void __iomem *addr, u32 value);
+};
+
+struct pci_mmcfg_region *pci_mmconfig_lookup(int segment, int bus);
+struct pci_mmcfg_region *pci_mmconfig_alloc(int segment, int start,
+						   int end, u64 addr);
+int pci_mmconfig_inject(struct pci_mmcfg_region *cfg);
+struct pci_mmcfg_region *pci_mmconfig_add(int segment, int start,
+						 int end, u64 addr);
+void list_add_sorted(struct pci_mmcfg_region *new);
+void free_all_mmcfg(void);
+int pci_mmconfig_delete(u16 seg, u8 start, u8 end);
+
+/* Arch specific calls */
+int pci_mmcfg_arch_init(void);
+void pci_mmcfg_arch_free(void);
+int pci_mmcfg_arch_map(struct pci_mmcfg_region *cfg);
+void pci_mmcfg_arch_unmap(struct pci_mmcfg_region *cfg);
+extern u32 pci_mmio_read(int len, void __iomem *addr);
+extern void pci_mmio_write(int len, void __iomem *addr, u32 value);
+extern void pci_mmconfig_register_mmio(struct pci_mmcfg_mmio_ops *ops);
+
+extern struct list_head pci_mmcfg_list;
+
+#define PCI_MMCFG_BUS_OFFSET(bus)      ((bus) << 20)
+
+#endif  /* __KERNEL__ */
+#endif  /* __ECAM_H */
-- 
1.9.1
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