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Subject[PATCH 2/2] PCI, ACPI, x86: update MMCFG information when hot-plugging PCI host bridges
Date
This patch enhances pci_root driver to update MMCFG information when
hot-plugging PCI root bridges on x86 platforms.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
---
arch/x86/pci/acpi.c | 58 ++++++++++++++++++++++++++++++++++++++++++++++
drivers/acpi/pci_root.c | 20 ++++++++++++++++
include/acpi/acnames.h | 1 +
include/linux/pci-acpi.h | 3 ++
4 files changed, 82 insertions(+), 0 deletions(-)
diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c
index da0149d..9184970 100644
--- a/arch/x86/pci/acpi.c
+++ b/arch/x86/pci/acpi.c
@@ -488,6 +488,64 @@ struct pci_bus * __devinit pci_acpi_scan_root(struct acpi_pci_root *root)
return bus;
}

+int arch_acpi_pci_root_add(struct acpi_pci_root *root)
+{
+ int result = 0;
+ acpi_status status;
+ unsigned long long base_addr;
+ struct pci_mmcfg_region *cfg;
+
+ /*
+ * Try to insert MMCFG information for host bridges with _CBA method
+ */
+ status = acpi_evaluate_integer(root->device->handle, METHOD_NAME__CBA,
+ NULL, &base_addr);
+ if (ACPI_SUCCESS(status)) {
+ result = pci_mmconfig_insert(root->segment,
+ root->secondary.start,
+ root->secondary.end,
+ base_addr);
+ /*
+ * MMCFG information for hot-pluggable host bridges may have
+ * already been added by __pci_mmcfg_init();
+ */
+ if (result == -EEXIST)
+ result = 0;
+ } else if (status == AE_NOT_FOUND) {
+ /*
+ * Check whether MMCFG information has been added for
+ * host bridges without _CBA method.
+ */
+ rcu_read_lock();
+ cfg = pci_mmconfig_lookup(root->segment, root->secondary.start);
+ if (!cfg || cfg->end_bus < root->secondary.end)
+ result = -ENODEV;
+ rcu_read_unlock();
+ } else
+ result = -ENODEV;
+
+ return result;
+}
+
+int arch_acpi_pci_root_remove(struct acpi_pci_root *root)
+{
+ acpi_status status;
+ unsigned long long base_addr;
+
+ /* Remove MMCFG information for host bridges with _CBA method */
+ status = acpi_evaluate_integer(root->device->handle, METHOD_NAME__CBA,
+ NULL, &base_addr);
+ if (ACPI_SUCCESS(status))
+ return pci_mmconfig_delete(root->segment,
+ root->secondary.start,
+ root->secondary.end,
+ base_addr);
+ else if (status != AE_NOT_FOUND)
+ return -ENODEV;
+
+ return 0;
+}
+
int __init pci_acpi_init(void)
{
struct pci_dev *dev = NULL;
diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index 4a7d575..a62bfa8 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)
+{
+ return 0;
+}
+
+int __weak arch_acpi_pci_root_remove(struct acpi_pci_root *root)
+{
+ return 0;
+}
+
static int __devinit acpi_pci_root_add(struct acpi_device *device)
{
unsigned long long segment, bus;
@@ -504,6 +514,14 @@ static int __devinit acpi_pci_root_add(struct acpi_device *device)
strcpy(acpi_device_class(device), ACPI_PCI_ROOT_CLASS);
device->driver_data = root;

+ if (arch_acpi_pci_root_add(root)) {
+ printk(KERN_ERR PREFIX
+ "can't add MMCFG information for Bus %04x:%02x\n",
+ root->segment, (unsigned int)root->secondary.start);
+ 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 +647,7 @@ 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;
@@ -679,6 +698,7 @@ 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/linux/pci-acpi.h b/include/linux/pci-acpi.h
index ac93634..816b971 100644
--- a/include/linux/pci-acpi.h
+++ b/include/linux/pci-acpi.h
@@ -38,6 +38,9 @@ static inline acpi_handle acpi_pci_get_bridge_handle(struct pci_bus *pbus)

void acpi_pci_root_rescan(void);

+extern int arch_acpi_pci_root_add(struct acpi_pci_root *root);
+extern int arch_acpi_pci_root_remove(struct acpi_pci_root *root);
+
#else

static inline void acpi_pci_root_rescan(void) { }
--
1.7.5.4


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