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@xxxxxxxxx>
---
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
--
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