Merge branch 'pci/resource'
- Evaluate ACPI "PCI Boot Configuration"_DSM (Benjamin Herrenschmidt)
- Don't auto-realloc if we're preserving firmware config (Benjamin
Herrenschmidt)
- Allow arm64 to reallocate resources if necessary (Benjamin
Herrenschmidt)
- Preserve firmware config on arm64 when desired (Benjamin Herrenschmidt)
- Simplify resource distribution to hotplug bridges (Nicholas Johnson)
* pci/resource:
PCI: Skip resource distribution when no hotplug bridges
PCI: Simplify pci_bus_distribute_available_resources()
arm64: PCI: Preserve firmware configuration when desired
arm64: PCI: Allow resource reallocation if necessary
PCI: Don't auto-realloc if we're preserving firmware config
PCI/ACPI: Evaluate PCI Boot Configuration _DSM
diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c
index bb85e2f..16fcb8d 100644
--- a/arch/arm64/kernel/pci.c
+++ b/arch/arm64/kernel/pci.c
@@ -168,6 +168,7 @@ struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root)
struct acpi_pci_generic_root_info *ri;
struct pci_bus *bus, *child;
struct acpi_pci_root_ops *root_ops;
+ struct pci_host_bridge *host;
ri = kzalloc(sizeof(*ri), GFP_KERNEL);
if (!ri)
@@ -193,8 +194,16 @@ struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root)
if (!bus)
return NULL;
- pci_bus_size_bridges(bus);
- pci_bus_assign_resources(bus);
+ /* If we must preserve the resource configuration, claim now */
+ host = pci_find_host_bridge(bus);
+ if (host->preserve_config)
+ pci_bus_claim_resources(bus);
+
+ /*
+ * Assign whatever was left unassigned. If we didn't claim above,
+ * this will reassign everything.
+ */
+ pci_assign_unassigned_root_bus_resources(bus);
list_for_each_entry(child, &bus->children, node)
pcie_bus_configure_settings(child);
diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index c36781a..0d57f81 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -894,6 +894,7 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
int node = acpi_get_node(device->handle);
struct pci_bus *bus;
struct pci_host_bridge *host_bridge;
+ union acpi_object *obj;
info->root = root;
info->bridge = device;
@@ -930,6 +931,17 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
if (!(root->osc_control_set & OSC_PCI_EXPRESS_LTR_CONTROL))
host_bridge->native_ltr = 0;
+ /*
+ * Evaluate the "PCI Boot Configuration" _DSM Function. If it
+ * exists and returns 0, we must preserve any PCI resource
+ * assignments made by firmware for this host bridge.
+ */
+ obj = acpi_evaluate_dsm(ACPI_HANDLE(bus->bridge), &pci_acpi_dsm_guid, 1,
+ IGNORE_PCI_BOOT_CONFIG_DSM, NULL);
+ if (obj && obj->type == ACPI_TYPE_INTEGER && obj->integer.value == 0)
+ host_bridge->preserve_config = 1;
+ ACPI_FREE(obj);
+
pci_scan_child_bus(bus);
pci_set_host_bridge_release(host_bridge, acpi_pci_root_release_info,
info);
diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index 0cdd5ff..79b1fa6 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -1684,10 +1684,15 @@ static enum enable_type pci_realloc_detect(struct pci_bus *bus,
enum enable_type enable_local)
{
bool unassigned = false;
+ struct pci_host_bridge *host;
if (enable_local != undefined)
return enable_local;
+ host = pci_find_host_bridge(bus);
+ if (host->preserve_config)
+ return auto_disabled;
+
pci_walk_bus(bus, iov_resources_unassigned, &unassigned);
if (unassigned)
return auto_enabled;
@@ -1861,16 +1866,6 @@ static void pci_bus_distribute_available_resources(struct pci_bus *bus,
available_mmio_pref);
/*
- * Calculate the total amount of extra resource space we can
- * pass to bridges below this one. This is basically the
- * extra space reduced by the minimal required space for the
- * non-hotplug bridges.
- */
- remaining_io = available_io;
- remaining_mmio = available_mmio;
- remaining_mmio_pref = available_mmio_pref;
-
- /*
* Calculate how many hotplug bridges and normal bridges there
* are on this bus. We will distribute the additional available
* resources between hotplug bridges.
@@ -1882,6 +1877,34 @@ static void pci_bus_distribute_available_resources(struct pci_bus *bus,
normal_bridges++;
}
+ /*
+ * There is only one bridge on the bus so it gets all available
+ * resources which it can then distribute to the possible hotplug
+ * bridges below.
+ */
+ if (hotplug_bridges + normal_bridges == 1) {
+ dev = list_first_entry(&bus->devices, struct pci_dev, bus_list);
+ if (dev->subordinate) {
+ pci_bus_distribute_available_resources(dev->subordinate,
+ add_list, available_io, available_mmio,
+ available_mmio_pref);
+ }
+ return;
+ }
+
+ if (hotplug_bridges == 0)
+ return;
+
+ /*
+ * Calculate the total amount of extra resource space we can
+ * pass to bridges below this one. This is basically the
+ * extra space reduced by the minimal required space for the
+ * non-hotplug bridges.
+ */
+ remaining_io = available_io;
+ remaining_mmio = available_mmio;
+ remaining_mmio_pref = available_mmio_pref;
+
for_each_pci_bridge(dev, bus) {
const struct resource *res;
@@ -1906,21 +1929,6 @@ static void pci_bus_distribute_available_resources(struct pci_bus *bus,
}
/*
- * There is only one bridge on the bus so it gets all available
- * resources which it can then distribute to the possible hotplug
- * bridges below.
- */
- if (hotplug_bridges + normal_bridges == 1) {
- dev = list_first_entry(&bus->devices, struct pci_dev, bus_list);
- if (dev->subordinate) {
- pci_bus_distribute_available_resources(dev->subordinate,
- add_list, available_io, available_mmio,
- available_mmio_pref);
- }
- return;
- }
-
- /*
* Go over devices on this bus and distribute the remaining
* resource space between hotplug bridges.
*/
@@ -1936,8 +1944,6 @@ static void pci_bus_distribute_available_resources(struct pci_bus *bus,
* Distribute available extra resources equally between
* hotplug-capable downstream ports taking alignment into
* account.
- *
- * Here hotplug_bridges is always != 0.
*/
align = pci_resource_alignment(bridge, io_res);
io = div64_ul(available_io, hotplug_bridges);
diff --git a/include/linux/pci-acpi.h b/include/linux/pci-acpi.h
index 8082b61..62b7fdc 100644
--- a/include/linux/pci-acpi.h
+++ b/include/linux/pci-acpi.h
@@ -107,9 +107,10 @@ static inline void acpiphp_check_host_bridge(struct acpi_device *adev) { }
#endif
extern const guid_t pci_acpi_dsm_guid;
-#define DEVICE_LABEL_DSM 0x07
-#define RESET_DELAY_DSM 0x08
-#define FUNCTION_DELAY_DSM 0x09
+#define IGNORE_PCI_BOOT_CONFIG_DSM 0x05
+#define DEVICE_LABEL_DSM 0x07
+#define RESET_DELAY_DSM 0x08
+#define FUNCTION_DELAY_DSM 0x09
#else /* CONFIG_ACPI */
static inline void acpi_pci_add_bus(struct pci_bus *bus) { }
diff --git a/include/linux/pci.h b/include/linux/pci.h
index ea91e79..bf6ea6f 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -508,6 +508,8 @@ struct pci_host_bridge {
unsigned int native_shpc_hotplug:1; /* OS may use SHPC hotplug */
unsigned int native_pme:1; /* OS may use PCIe PME */
unsigned int native_ltr:1; /* OS may use PCIe LTR */
+ unsigned int preserve_config:1; /* Preserve FW resource setup */
+
/* Resource alignment requirements */
resource_size_t (*align_resource)(struct pci_dev *dev,
const struct resource *res,
