[PATCH v5 6/6] PCI, ACPI, x86: update MMCFG information when hot-plugging PCI host bridges

[Jiang Liu <liuj97@gmail.com>]

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

This patch enhances pci_root driver to update MMCFG information when
hot-plugging PCI root bridges on x86 platforms.

Signed-off-by: Jiang Liu <liuj97@gmail.com>
---
 arch/x86/include/asm/pci_x86.h |    1 +
 arch/x86/pci/acpi.c            |   57 ++++++++++++++++++++++++++++++++++++++++
 arch/x86/pci/mmconfig_32.c     |    2 +-
 arch/x86/pci/mmconfig_64.c     |    2 +-
 drivers/acpi/pci_root.c        |   22 ++++++++++++++++
 include/acpi/acnames.h         |    1 +
 include/acpi/acpi_bus.h        |    1 +
 include/linux/pci-acpi.h       |    4 +++
 8 files changed, 88 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/pci_x86.h b/arch/x86/include/asm/pci_x86.h
index 3252c97..5e1d9a6 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 da0149d..80cc3fa 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>
 
@@ -488,6 +489,62 @@ struct pci_bus * __devinit pci_acpi_scan_root(struct acpi_pci_root *root)
 	return bus;
 }
 
+int __devinit arch_acpi_pci_root_add(struct acpi_pci_root *root,
+				     unsigned long long base_addr)
+{
+	int result;
+
+	/* 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 (root->segment == 0)
+			return 0;
+
+		printk(KERN_ERR "MMCFG is disabled, "
+			"can't access CFG space for Bus %04x:%02x\n",
+			root->segment, (unsigned int)root->secondary.start);
+		return -ENODEV;
+	}
+
+	result = pci_mmconfig_insert(root->segment, root->secondary.start,
+				     root->secondary.end, base_addr);
+	if (result == -EEXIST) {
+		/* return success if MMCFG item already exists */
+		result = 0;
+	} else if (result == 0) {
+		/* enable MMCFG if it hasn't been enabled yet */
+		if (raw_pci_ext_ops == NULL)
+			raw_pci_ext_ops = &pci_mmcfg;
+		root->mmconf_added = true;
+	} else if (root->segment == 0 && raw_pci_ext_ops == NULL &&
+		   raw_pci_ops != NULL) {
+		/*
+		 * system doesn't support extended configuration space,
+		 * still could use raw_pci_ops with it
+		 */
+		result = 0;
+	} else {
+		printk(KERN_ERR
+			"can't add MMCFG information for Bus %04x:%02x\n",
+			root->segment, (unsigned int)root->secondary.start);
+	}
+
+	return result;
+}
+
+void arch_acpi_pci_root_remove(struct acpi_pci_root *root)
+{
+	if (root->mmconf_added) {
+		pci_mmconfig_delete(root->segment,
+				    root->secondary.start,
+				    root->secondary.end);
+		root->mmconf_added = false;
+	}
+}
+
 int __init pci_acpi_init(void)
 {
 	struct pci_dev *dev = 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,
 };
diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index b313125..8d3f821 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -448,6 +448,16 @@ out:
 }
 EXPORT_SYMBOL(acpi_pci_osc_control_set);
 
+int __weak arch_acpi_pci_root_add(struct acpi_pci_root *root,
+				  unsigned long long base_addr)
+{
+	return 0;
+}
+
+void __weak arch_acpi_pci_root_remove(struct acpi_pci_root *root)
+{
+}
+
 static int __devinit acpi_pci_root_add(struct acpi_device *device)
 {
 	unsigned long long segment, bus;
@@ -457,6 +467,7 @@ static int __devinit acpi_pci_root_add(struct acpi_device *device)
 	acpi_handle handle;
 	struct acpi_device *child;
 	u32 flags, base_flags;
+	unsigned long long base_addr;
 
 	root = kzalloc(sizeof(struct acpi_pci_root), GFP_KERNEL);
 	if (!root)
@@ -504,6 +515,15 @@ static int __devinit acpi_pci_root_add(struct acpi_device *device)
 	strcpy(acpi_device_class(device), ACPI_PCI_ROOT_CLASS);
 	device->driver_data = root;
 
+	status = acpi_evaluate_integer(root->device->handle, METHOD_NAME__CBA,
+				       NULL, &base_addr);
+	if (ACPI_FAILURE(status))
+		base_addr = 0;
+	if (arch_acpi_pci_root_add(root, base_addr)) {
+		result = -ENODEV;
+		goto out_free;
+	}
+
 	/*
 	 * All supported architectures that use ACPI have support for
 	 * PCI domains, so we indicate this in _OSC support capabilities.
@@ -629,6 +649,7 @@ out_del_root:
 	list_del_rcu(&root->node);
 	mutex_unlock(&acpi_pci_root_lock);
 	synchronize_rcu();
+	arch_acpi_pci_root_remove(root);
 out_free:
 	kfree(root);
 	return result;
@@ -686,6 +707,7 @@ out:
 	list_del_rcu(&root->node);
 	mutex_unlock(&acpi_pci_root_lock);
 	synchronize_rcu();
+	arch_acpi_pci_root_remove(root);
 	kfree(root);
 
 	return 0;
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 333d38c..4171277 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -371,6 +371,7 @@ struct acpi_pci_root {
 	u32 osc_support_set;	/* _OSC state of support bits */
 	u32 osc_control_set;	/* _OSC state of control bits */
 	bool hot_added;
+	bool mmconf_added;
 };
 
 /* helper */
diff --git a/include/linux/pci-acpi.h b/include/linux/pci-acpi.h
index 4462350..d017dc0 100644
--- a/include/linux/pci-acpi.h
+++ b/include/linux/pci-acpi.h
@@ -18,6 +18,10 @@ 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);
 
+int arch_acpi_pci_root_add(struct acpi_pci_root *root,
+			   unsigned long long base_addr);
+void arch_acpi_pci_root_remove(struct acpi_pci_root *root);
+
 static inline acpi_handle acpi_find_root_bridge_handle(struct pci_dev *pdev)
 {
 	struct pci_bus *pbus = pdev->bus;
-- 
1.7.9.5