[PATCH v9 07/11] PCI, acpiphp: Move and enhance hotplug support of pci host bridge

From: Yinghai Lu
Date: Fri Jan 18 2013 - 02:53:36 EST


We have partial hot-add support in acpiphp driver, and it is confusing.

Move host bridge hot-add support to pci_root.c, and keep acpiphp simple,
also add hot-remove support in pci_root.c.

How to test it: if sci_emu patch is applied,

Find out root bus number to acpi root name mapping from dmesg or /sys

echo "\_SB.PCIB 3" > /sys/kernel/debug/acpi/sci_notify
to remove root bus

echo "\_SB.PCIB 1" > /sys/kernel/debug/acpi/sci_notify
to add back root bus

-v2: put back pci_root_hp change in one patch
-v3: add pcibios_resource_survey_bus() calling
-v4: remove not needed code with remove_bridge
-v5: put back support for acpiphp support for slots just on root bus.
-v6: change some functions to *_p2p_* to make it more clean.
-v7: split hot_added change out.
-v8: Move to pci_root.c instead of adding another file requested by Bjorn.
-v9: Fold three following patches into this one for easy review:
a: Add missing hot_remove support for root device.
b: Tang Chen noticed that hotplug through container will not update
acpi_root_bridge list. After closely checking, we don't need
that for struct for tracking and could use acpi_pci_root directly.
c: Tang Chen found handle_root_bridge_removal is very similiar to
acpi_bus_hot_remove_device(). Change to handle_root_bridge_removal
to use acpi_bus_hot_remove_device.

Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>
---
drivers/acpi/pci_root.c | 139 ++++++++++++++++++++++++++++++++++++
drivers/pci/hotplug/acpiphp_glue.c | 59 ++++-----------
2 files changed, 154 insertions(+), 44 deletions(-)

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index bf5108a..3ce5d80 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -655,3 +655,142 @@ int __init acpi_pci_root_init(void)

return 0;
}
+
+/* Support root bridge hotplug */
+
+static void handle_root_bridge_insertion(acpi_handle handle)
+{
+ struct acpi_device *device, *pdevice;
+ acpi_handle phandle;
+ int ret_val;
+
+ acpi_get_parent(handle, &phandle);
+ if (acpi_bus_get_device(phandle, &pdevice)) {
+ printk(KERN_DEBUG "no parent device, assuming NULL\n");
+ pdevice = NULL;
+ }
+ if (!acpi_bus_get_device(handle, &device)) {
+ /* check if pci root_bus is removed */
+ struct acpi_pci_root *root = acpi_driver_data(device);
+ if (pci_find_bus(root->segment, root->secondary.start))
+ return;
+
+ printk(KERN_DEBUG "bus exists... trim\n");
+ /* this shouldn't be in here, so remove
+ * the bus then re-add it...
+ */
+ ret_val = acpi_bus_trim(device);
+ printk(KERN_DEBUG "acpi_bus_trim return %x\n", ret_val);
+ }
+ if (acpi_bus_add(handle))
+ printk(KERN_ERR "cannot add bridge to acpi list\n");
+}
+
+static void handle_root_bridge_removal(struct acpi_device *device)
+{
+ struct acpi_eject_event *ej_event;
+
+ ej_event = kmalloc(sizeof(*ej_event), GFP_KERNEL);
+ if (!ej_event)
+ return;
+
+ ej_event->device = device;
+ ej_event->event = ACPI_NOTIFY_EJECT_REQUEST;
+
+ acpi_bus_hot_remove_device(ej_event);
+}
+
+static void _handle_hotplug_event_root(struct work_struct *work)
+{
+ struct acpi_pci_root *root;
+ char objname[64];
+ struct acpi_buffer buffer = { .length = sizeof(objname),
+ .pointer = objname };
+ struct acpi_hp_work *hp_work;
+ acpi_handle handle;
+ u32 type;
+
+ hp_work = container_of(work, struct acpi_hp_work, work);
+ handle = hp_work->handle;
+ type = hp_work->type;
+
+ root = acpi_pci_find_root(handle);
+
+ acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
+
+ switch (type) {
+ case ACPI_NOTIFY_BUS_CHECK:
+ /* bus enumerate */
+ printk(KERN_DEBUG "%s: Bus check notify on %s\n", __func__,
+ objname);
+ if (!root)
+ handle_root_bridge_insertion(handle);
+
+ break;
+
+ case ACPI_NOTIFY_DEVICE_CHECK:
+ /* device check */
+ printk(KERN_DEBUG "%s: Device check notify on %s\n", __func__,
+ objname);
+ if (!root)
+ handle_root_bridge_insertion(handle);
+ break;
+
+ case ACPI_NOTIFY_EJECT_REQUEST:
+ /* request device eject */
+ printk(KERN_DEBUG "%s: Device eject notify on %s\n", __func__,
+ objname);
+ if (root)
+ handle_root_bridge_removal(root->device);
+ break;
+ default:
+ printk(KERN_WARNING "notify_handler: unknown event type 0x%x for %s\n",
+ type, objname);
+ break;
+ }
+
+ kfree(hp_work); /* allocated in handle_hotplug_event_bridge */
+}
+
+static void handle_hotplug_event_root(acpi_handle handle, u32 type,
+ void *context)
+{
+ alloc_acpi_hp_work(handle, type, context,
+ _handle_hotplug_event_root);
+}
+
+static acpi_status __init
+find_root_bridges(acpi_handle handle, u32 lvl, void *context, void **rv)
+{
+ char objname[64];
+ struct acpi_buffer buffer = { .length = sizeof(objname),
+ .pointer = objname };
+ int *count = (int *)context;
+
+ if (!acpi_is_root_bridge(handle))
+ return AE_OK;
+
+ (*count)++;
+
+ acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
+
+ acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
+ handle_hotplug_event_root, NULL);
+ printk(KERN_DEBUG "acpi root: %s notify handler installed\n", objname);
+
+ return AE_OK;
+}
+
+static int __init acpi_pci_root_hp_init(void)
+{
+ int num = 0;
+
+ acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
+ ACPI_UINT32_MAX, find_root_bridges, NULL, &num, NULL);
+
+ printk(KERN_DEBUG "Found %d acpi root devices\n", num);
+
+ return 0;
+}
+
+subsys_initcall(acpi_pci_root_hp_init);
diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c
index 55e03b6..45917a5 100644
--- a/drivers/pci/hotplug/acpiphp_glue.c
+++ b/drivers/pci/hotplug/acpiphp_glue.c
@@ -543,10 +543,13 @@ static void cleanup_bridge(struct acpiphp_bridge *bridge)
acpi_status status;
acpi_handle handle = bridge->handle;

- status = acpi_remove_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
+ if (bridge->type != BRIDGE_TYPE_HOST) {
+ status = acpi_remove_notify_handler(handle,
+ ACPI_SYSTEM_NOTIFY,
handle_hotplug_event_bridge);
- if (ACPI_FAILURE(status))
- err("failed to remove notify handler\n");
+ if (ACPI_FAILURE(status))
+ err("failed to remove notify handler\n");
+ }

if ((bridge->type != BRIDGE_TYPE_HOST) &&
((bridge->flags & BRIDGE_HAS_EJ0) && bridge->func)) {
@@ -630,9 +633,6 @@ static void remove_bridge(struct acpi_pci_root *root)
bridge = acpiphp_handle_to_bridge(handle);
if (bridge)
cleanup_bridge(bridge);
- else
- acpi_remove_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
- handle_hotplug_event_bridge);
}

static int power_on_slot(struct acpiphp_slot *slot)
@@ -1123,18 +1123,12 @@ static void acpiphp_sanitize_bus(struct pci_bus *bus)
}

/* Program resources in newly inserted bridge */
-static int acpiphp_configure_bridge (acpi_handle handle)
+static int acpiphp_configure_p2p_bridge(acpi_handle handle)
{
- struct pci_bus *bus;
+ struct pci_dev *pdev = acpi_get_pci_dev(handle);
+ struct pci_bus *bus = pdev->subordinate;

- if (acpi_is_root_bridge(handle)) {
- struct acpi_pci_root *root = acpi_pci_find_root(handle);
- bus = root->bus;
- } else {
- struct pci_dev *pdev = acpi_get_pci_dev(handle);
- bus = pdev->subordinate;
- pci_dev_put(pdev);
- }
+ pci_dev_put(pdev);

pci_bus_size_bridges(bus);
pci_bus_assign_resources(bus);
@@ -1144,7 +1138,7 @@ static int acpiphp_configure_bridge (acpi_handle handle)
return 0;
}

-static void handle_bridge_insertion(acpi_handle handle, u32 type)
+static void handle_p2p_bridge_insertion(acpi_handle handle, u32 type)
{
struct acpi_device *device;

@@ -1162,8 +1156,8 @@ static void handle_bridge_insertion(acpi_handle handle, u32 type)
err("ACPI device object missing\n");
return;
}
- if (!acpiphp_configure_bridge(handle))
- add_bridge(handle);
+ if (!acpiphp_configure_p2p_bridge(handle))
+ add_p2p_bridge(handle);
else
err("cannot configure and start bridge\n");

@@ -1221,7 +1215,7 @@ static void _handle_hotplug_event_bridge(struct work_struct *work)

if (acpi_bus_get_device(handle, &device)) {
/* This bridge must have just been physically inserted */
- handle_bridge_insertion(handle, type);
+ handle_p2p_bridge_insertion(handle, type);
goto out;
}

@@ -1396,21 +1390,6 @@ static void handle_hotplug_event_func(acpi_handle handle, u32 type,
alloc_acpi_hp_work(handle, type, context, _handle_hotplug_event_func);
}

-static acpi_status
-find_root_bridges(acpi_handle handle, u32 lvl, void *context, void **rv)
-{
- int *count = (int *)context;
-
- if (!acpi_is_root_bridge(handle))
- return AE_OK;
-
- (*count)++;
- acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
- handle_hotplug_event_bridge, NULL);
-
- return AE_OK ;
-}
-
static struct acpi_pci_driver acpi_pci_hp_driver = {
.add = add_bridge,
.remove = remove_bridge,
@@ -1421,15 +1400,7 @@ static struct acpi_pci_driver acpi_pci_hp_driver = {
*/
int __init acpiphp_glue_init(void)
{
- int num = 0;
-
- acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
- ACPI_UINT32_MAX, find_root_bridges, NULL, &num, NULL);
-
- if (num <= 0)
- return -1;
- else
- acpi_pci_register_driver(&acpi_pci_hp_driver);
+ acpi_pci_register_driver(&acpi_pci_hp_driver);

return 0;
}
--
1.7.10.4

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