[PATCH v6 6/9] PCI, ACPI: provide MCFG address for PCI host bridges

[PATCH v6 6/9] PCI, ACPI: provide MCFG address for PCI host bridges

[Jiang Liu]

From: Jiang Liu <liuj97@gmail.com>

From: Jiang Liu <jiang.liu@huawei.com>

This patch provide MCFG address for PCI host bridges, which will
be used to support host bridge hotplug. It gets MCFG address
by evaluating _CBA method if available, or by scanning the ACPI
MCFG table.

Signed-off-by: Jiang Liu <liuj97@gmail.com>
---
 drivers/acpi/pci_root.c  |   12 ++++++++++++
 drivers/pci/pci-acpi.c   |   34 ++++++++++++++++++++++++++++++++++
 include/acpi/acnames.h   |    1 +
 include/acpi/acpi_bus.h  |    3 +++
 include/linux/pci-acpi.h |    5 +++++
 5 files changed, 55 insertions(+), 0 deletions(-)

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index 7aff631..fc716cf 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -458,6 +458,7 @@ static int __devinit acpi_pci_root_add(struct acpi_device *device)
 	acpi_handle handle;
 	struct acpi_device *child;
 	u32 flags, base_flags;
+	int end_bus = -1;
 
 	root = kzalloc(sizeof(struct acpi_pci_root), GFP_KERNEL);
 	if (!root)
@@ -505,6 +506,17 @@ static int __devinit acpi_pci_root_add(struct acpi_device *device)
 	strcpy(acpi_device_class(device), ACPI_PCI_ROOT_CLASS);
 	device->driver_data = root;
 
+	root->mcfg_addr = acpi_pci_root_get_mcfg_addr(device->handle,
+		root->segment, (uint8_t)root->secondary.start, &end_bus);
+
+	/*
+	 * End bus number for MCFG may be less than root's subordinary
+	 * bus number with buggy BIOS implementation.
+	 */
+	if (end_bus < 0 || end_bus > root->secondary.end)
+		end_bus = root->secondary.end;
+	root->mcfg_end_bus = (uint8_t)end_bus;
+
 	/*
 	 * All supported architectures that use ACPI have support for
 	 * PCI domains, so we indicate this in _OSC support capabilities.
diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
index 0f150f2..9af71d2 100644
--- a/drivers/pci/pci-acpi.c
+++ b/drivers/pci/pci-acpi.c
@@ -162,6 +162,40 @@ acpi_status pci_acpi_remove_pm_notifier(struct acpi_device *dev)
 	return remove_pm_notifier(dev, pci_acpi_wake_dev);
 }
 
+/* acpi_table_parse() is marked as __init, so cache MCFG info at boot time */
+int pci_acpi_mcfg_entries;
+struct acpi_mcfg_allocation *pci_acpi_mcfg_array;
+
+phys_addr_t acpi_pci_root_get_mcfg_addr(acpi_handle handle, uint16_t seg,
+					uint8_t start, int *endp)
+{
+	int i, end_bus = -1;
+	acpi_status status = AE_NOT_EXIST;
+	unsigned long long mcfg_addr = 0;
+	struct acpi_mcfg_allocation *cfg;
+
+	if (handle)
+		status = acpi_evaluate_integer(handle, METHOD_NAME__CBA,
+					       NULL, &mcfg_addr);
+	if (ACPI_FAILURE(status) && pci_acpi_mcfg_entries &&
+	    pci_acpi_mcfg_array) {
+		mcfg_addr = 0;
+		cfg = pci_acpi_mcfg_array;
+		for (i = 0; i < pci_acpi_mcfg_entries; i++, cfg++)
+			if (seg == cfg->pci_segment &&
+			    start >= cfg->start_bus_number &&
+			    start <= cfg->end_bus_number) {
+				end_bus = cfg->end_bus_number;
+				mcfg_addr = cfg->address;
+				break;
+			}
+	}
+	if (endp)
+		*endp = end_bus;
+
+	return (phys_addr_t)mcfg_addr;
+}
+
 /*
  * _SxD returns the D-state with the highest power
  * (lowest D-state number) supported in the S-state "x".
diff --git a/include/acpi/acnames.h b/include/acpi/acnames.h
index 38f5088..99bda75 100644
--- a/include/acpi/acnames.h
+++ b/include/acpi/acnames.h
@@ -62,6 +62,7 @@
 #define METHOD_NAME__AEI        "_AEI"
 #define METHOD_NAME__PRW        "_PRW"
 #define METHOD_NAME__SRS        "_SRS"
+#define METHOD_NAME__CBA	"_CBA"
 
 /* Method names - these methods must appear at the namespace root */
 
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index f1c8ca6..8bc5229 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -370,6 +370,9 @@ struct acpi_pci_root {
 
 	u32 osc_support_set;	/* _OSC state of support bits */
 	u32 osc_control_set;	/* _OSC state of control bits */
+	uint8_t mcfg_end_bus;	/* End bus for MCFG may differ from
+				 * root's subordinary bus. */
+	phys_addr_t mcfg_addr;
 };
 
 /* helper */
diff --git a/include/linux/pci-acpi.h b/include/linux/pci-acpi.h
index 4462350..0369149 100644
--- a/include/linux/pci-acpi.h
+++ b/include/linux/pci-acpi.h
@@ -11,12 +11,17 @@
 #include <linux/acpi.h>
 
 #ifdef CONFIG_ACPI
+extern int pci_acpi_mcfg_entries;
+extern struct acpi_mcfg_allocation *pci_acpi_mcfg_array;
+
 extern acpi_status pci_acpi_add_bus_pm_notifier(struct acpi_device *dev,
 						 struct pci_bus *pci_bus);
 extern acpi_status pci_acpi_remove_bus_pm_notifier(struct acpi_device *dev);
 extern acpi_status pci_acpi_add_pm_notifier(struct acpi_device *dev,
 					     struct pci_dev *pci_dev);
 extern acpi_status pci_acpi_remove_pm_notifier(struct acpi_device *dev);
+extern phys_addr_t acpi_pci_root_get_mcfg_addr(acpi_handle handle,
+			uint16_t seg, uint8_t start, int *endp);
 
 static inline acpi_handle acpi_find_root_bridge_handle(struct pci_dev *pdev)
 {
-- 
1.7.1

[PATCH v6 7/9] PCI, x86: update MMCFG information when hot-plugging PCI host bridges

[Jiang Liu]

From: Jiang Liu <liuj97@gmail.com>

From: Jiang Liu <jiang.liu@huawei.com>

This patch enhances x86 arch specific code to update MMCFG information
when PCI host bridge hotplug event happens.

Signed-off-by: Jiang Liu <liuj97@gmail.com>
---
 arch/x86/include/asm/pci_x86.h |    1 +
 arch/x86/pci/acpi.c            |   71 ++++++++++++++++++++++++++++++++++++++++
 arch/x86/pci/mmconfig-shared.c |    7 +---
 arch/x86/pci/mmconfig_32.c     |    2 +-
 arch/x86/pci/mmconfig_64.c     |    2 +-
 5 files changed, 75 insertions(+), 8 deletions(-)

diff --git a/arch/x86/include/asm/pci_x86.h b/arch/x86/include/asm/pci_x86.h
index 1a3c12f..a50e783 100644
--- a/arch/x86/include/asm/pci_x86.h
+++ b/arch/x86/include/asm/pci_x86.h
@@ -100,6 +100,7 @@ struct pci_raw_ops {
 extern const struct pci_raw_ops *raw_pci_ops;
 extern const struct pci_raw_ops *raw_pci_ext_ops;
 
+extern const struct pci_raw_ops pci_mmcfg;
 extern const struct pci_raw_ops pci_direct_conf1;
 extern bool port_cf9_safe;
 
diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c
index 2bb885a..ce29bdf 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/pci-acpi.h>
 #include <asm/numa.h>
 #include <asm/pci_x86.h>
 
@@ -13,6 +14,12 @@ struct pci_root_info {
 	unsigned int res_num;
 	struct resource *res;
 	struct pci_sysdata sd;
+#ifdef	CONFIG_PCI_MMCONFIG
+	bool mcfg_added;
+	uint16_t segment;
+	uint8_t start_bus;
+	uint8_t end_bus;
+#endif
 };
 
 static bool pci_use_crs = true;
@@ -119,6 +126,63 @@ void __init pci_acpi_crs_quirks(void)
 	       pci_use_crs ? "nocrs" : "use_crs");
 }
 
+static int __devinit setup_mcfg_map(struct pci_root_info *info,
+				    uint16_t seg, uint8_t start, uint8_t end,
+				    phys_addr_t addr)
+{
+#ifdef	CONFIG_PCI_MMCONFIG
+	int result;
+
+	info->start_bus = start;
+	info->end_bus = end;
+	info->mcfg_added = false;
+
+	/* return success if MMCFG is not in use */
+	if (raw_pci_ext_ops && raw_pci_ext_ops != &pci_mmcfg)
+		return 0;
+
+	if (!(pci_probe & PCI_PROBE_MMCONF)) {
+		/* still could use raw_pci_ops for devices on segment 0 */
+		if (seg)
+			printk(KERN_WARNING
+				"MMCONFIG is disabled, can't access PCI device "
+				"configuration space on  %04x:%02x-%02x\n",
+				seg, start, end);
+		return 0;
+	}
+
+	result = pci_mmconfig_insert(seg, start, end, addr);
+	if (result == 0) {
+		/* enable MMCFG if it hasn't been enabled yet */
+		if (raw_pci_ext_ops == NULL)
+			raw_pci_ext_ops = &pci_mmcfg;
+		info->mcfg_added = true;
+	} else if (result != -EEXIST && addr) {
+		/*
+		 * Failure in adding MMCFG information is not fatal,
+		 * just can't access [extended] configuration space of
+		 * devices under this host bridge.
+		 */
+		printk(KERN_WARNING
+			"Fail to add MMCONFIG information for %04x:%02x-%02x\n",
+			seg, start, end);
+	}
+#endif
+
+	return 0;
+}
+
+static void teardown_mcfg_map(struct pci_root_info *info)
+{
+#ifdef	CONFIG_PCI_MMCONFIG
+	if (info->mcfg_added) {
+		pci_mmconfig_delete(info->segment, info->start_bus,
+				    info->end_bus);
+		info->mcfg_added = false;
+	}
+#endif
+}
+
 static acpi_status
 resource_to_addr(struct acpi_resource *resource,
 			struct acpi_resource_address64 *addr)
@@ -331,6 +395,8 @@ static void __release_pci_root_info(struct pci_root_info *info)
 
 	free_pci_root_info_res(info);
 
+	teardown_mcfg_map(info);
+
 	kfree(info);
 }
 static void release_pci_root_info(struct pci_host_bridge *bridge)
@@ -423,6 +489,11 @@ struct pci_bus * __devinit pci_acpi_scan_root(struct acpi_pci_root *root)
 		memcpy(bus->sysdata, sd, sizeof(*sd));
 		kfree(info);
 	} else {
+		if (root->mcfg_addr)
+			setup_mcfg_map(info, root->segment,
+				       (uint8_t)root->secondary.start,
+				       root->mcfg_end_bus, root->mcfg_addr);
+
 		probe_pci_root_info(info, device, busnum, domain);
 
 		/* insert busn res at first */
diff --git a/arch/x86/pci/mmconfig-shared.c b/arch/x86/pci/mmconfig-shared.c
index 8d0c287..4d0600b 100644
--- a/arch/x86/pci/mmconfig-shared.c
+++ b/arch/x86/pci/mmconfig-shared.c
@@ -707,7 +707,7 @@ int __devinit pci_mmconfig_insert(uint16_t seg, uint8_t start, uint8_t end,
 	struct resource *tmp;
 	struct pci_mmcfg_region *cfg;
 
-	if (start > end)
+	if (start > end || !addr)
 		return -EINVAL;
 
 	if (pci_mmcfg_arch_init_failed)
@@ -726,11 +726,6 @@ int __devinit pci_mmconfig_insert(uint16_t seg, uint8_t start, uint8_t end,
 		return -EEXIST;
 	}
 
-	if (!addr) {
-		mutex_unlock(&pci_mmcfg_lock);
-		return -EINVAL;
-	}
-
 	rc = -EBUSY;
 	cfg = pci_mmconfig_alloc(seg, start, end, addr);
 	if (cfg == NULL) {
diff --git a/arch/x86/pci/mmconfig_32.c b/arch/x86/pci/mmconfig_32.c
index a22785d..db63ac2 100644
--- a/arch/x86/pci/mmconfig_32.c
+++ b/arch/x86/pci/mmconfig_32.c
@@ -126,7 +126,7 @@ static int pci_mmcfg_write(unsigned int seg, unsigned int bus,
 	return 0;
 }
 
-static const struct pci_raw_ops pci_mmcfg = {
+const struct pci_raw_ops pci_mmcfg = {
 	.read =		pci_mmcfg_read,
 	.write =	pci_mmcfg_write,
 };
diff --git a/arch/x86/pci/mmconfig_64.c b/arch/x86/pci/mmconfig_64.c
index 4e05779..34c08dd 100644
--- a/arch/x86/pci/mmconfig_64.c
+++ b/arch/x86/pci/mmconfig_64.c
@@ -90,7 +90,7 @@ static int pci_mmcfg_write(unsigned int seg, unsigned int bus,
 	return 0;
 }
 
-static const struct pci_raw_ops pci_mmcfg = {
+const struct pci_raw_ops pci_mmcfg = {
 	.read =		pci_mmcfg_read,
 	.write =	pci_mmcfg_write,
 };
-- 
1.7.1