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    Subject[PATCH v2 23/37] PCI, ACPI: Add pci_root_hp hot add hotplug notification
    Date
    It is from acpiphp_glue.c

    How to use it?
    Find out root bus number to acpi root name mapping from dmesg or /sys

    echo "\_SB.PCIB 0" > /proc/acpi/sci/notify
    to add it back

    Signed-off-by: Yinghai Lu <yinghai@kernel.org>
    Cc: Len Brown <lenb@kernel.org>
    Cc: linux-acpi@vger.kernel.org
    ---
    drivers/acpi/Makefile | 1 +
    drivers/acpi/pci_root_hp.c | 237 ++++++++++++++++++++++++++++++++++++++++++++
    2 files changed, 238 insertions(+), 0 deletions(-)
    create mode 100644 drivers/acpi/pci_root_hp.c

    diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
    index 1567028..bc6e53f 100644
    --- a/drivers/acpi/Makefile
    +++ b/drivers/acpi/Makefile
    @@ -36,6 +36,7 @@ acpi-y += processor_core.o
    acpi-y += ec.o
    acpi-$(CONFIG_ACPI_DOCK) += dock.o
    acpi-y += pci_root.o pci_link.o pci_irq.o pci_bind.o
    +acpi-$(CONFIG_HOTPLUG) += pci_root_hp.o
    acpi-y += power.o
    acpi-y += event.o
    acpi-y += sysfs.o
    diff --git a/drivers/acpi/pci_root_hp.c b/drivers/acpi/pci_root_hp.c
    new file mode 100644
    index 0000000..dc11e81
    --- /dev/null
    +++ b/drivers/acpi/pci_root_hp.c
    @@ -0,0 +1,237 @@
    +/*
    + * Separated from drivers/pci/hotplug/acpiphp_glue.c
    + * only support root bridge
    + */
    +
    +#include <linux/init.h>
    +#include <linux/module.h>
    +
    +#include <linux/kernel.h>
    +#include <linux/pci.h>
    +#include <linux/mutex.h>
    +#include <linux/slab.h>
    +#include <linux/acpi.h>
    +
    +static LIST_HEAD(acpi_root_bridge_list);
    +struct acpi_root_bridge {
    + struct list_head list;
    + acpi_handle handle;
    + u32 flags;
    +};
    +
    +/* bridge flags */
    +#define ROOT_BRIDGE_HAS_EJ0 (0x00000002)
    +#define ROOT_BRIDGE_HAS_PS3 (0x00000080)
    +
    +#define ACPI_STA_FUNCTIONING (0x00000008)
    +
    +static struct acpi_root_bridge *acpi_root_handle_to_bridge(acpi_handle handle)
    +{
    + struct acpi_root_bridge *bridge;
    +
    + list_for_each_entry(bridge, &acpi_root_bridge_list, list)
    + if (bridge->handle == handle)
    + return bridge;
    +
    + return NULL;
    +}
    +
    +/* allocate and initialize host bridge data structure */
    +static void add_acpi_root_bridge(acpi_handle handle)
    +{
    + struct acpi_root_bridge *bridge;
    + acpi_handle dummy_handle;
    + acpi_status status;
    +
    + /* if the bridge doesn't have _STA, we assume it is always there */
    + status = acpi_get_handle(handle, "_STA", &dummy_handle);
    + if (ACPI_SUCCESS(status)) {
    + unsigned long long tmp;
    +
    + status = acpi_evaluate_integer(handle, "_STA", NULL, &tmp);
    + if (ACPI_FAILURE(status)) {
    + printk(KERN_DEBUG "%s: _STA evaluation failure\n",
    + __func__);
    + return;
    + }
    + if ((tmp & ACPI_STA_FUNCTIONING) == 0)
    + /* don't register this object */
    + return;
    + }
    +
    + bridge = kzalloc(sizeof(struct acpi_root_bridge), GFP_KERNEL);
    + if (!bridge)
    + return;
    +
    + bridge->handle = handle;
    +
    + if (ACPI_SUCCESS(acpi_get_handle(handle, "_EJ0", &dummy_handle)))
    + bridge->flags |= ROOT_BRIDGE_HAS_EJ0;
    + if (ACPI_SUCCESS(acpi_get_handle(handle, "_PS3", &dummy_handle)))
    + bridge->flags |= ROOT_BRIDGE_HAS_PS3;
    +
    + list_add(&bridge->list, &acpi_root_bridge_list);
    +}
    +
    +struct acpi_root_hp_work {
    + struct work_struct work;
    + acpi_handle handle;
    + u32 type;
    + void *context;
    +};
    +
    +static void alloc_acpi_root_hp_work(acpi_handle handle, u32 type,
    + void *context,
    + void (*func)(struct work_struct *work))
    +{
    + struct acpi_root_hp_work *hp_work;
    + int ret;
    +
    + hp_work = kmalloc(sizeof(*hp_work), GFP_KERNEL);
    + if (!hp_work)
    + return;
    +
    + hp_work->handle = handle;
    + hp_work->type = type;
    + hp_work->context = context;
    +
    + INIT_WORK(&hp_work->work, func);
    + ret = queue_work(kacpi_hotplug_wq, &hp_work->work);
    + if (!ret)
    + kfree(hp_work);
    +}
    +
    +/* Program resources in newly inserted bridge */
    +static void acpi_root_configure_bridge(acpi_handle handle)
    +{
    + struct acpi_pci_root *root = acpi_pci_find_root(handle);
    +
    + pci_assign_unassigned_bus_resources(root->bus);
    +}
    +
    +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, 1);
    + printk(KERN_DEBUG "acpi_bus_trim return %x\n", ret_val);
    + }
    + if (acpi_bus_add(&device, pdevice, handle, ACPI_BUS_TYPE_DEVICE)) {
    + printk(KERN_ERR "cannot add bridge to acpi list\n");
    + return;
    + }
    + acpi_root_configure_bridge(handle);
    + if (acpi_bus_start(device))
    + printk(KERN_ERR "cannot start bridge\n");
    +}
    +
    +static void _handle_hotplug_event_root(struct work_struct *work)
    +{
    + struct acpi_root_bridge *bridge;
    + char objname[64];
    + struct acpi_buffer buffer = { .length = sizeof(objname),
    + .pointer = objname };
    + struct acpi_root_hp_work *hp_work;
    + acpi_handle handle;
    + u32 type;
    +
    + hp_work = container_of(work, struct acpi_root_hp_work, work);
    + handle = hp_work->handle;
    + type = hp_work->type;
    +
    + bridge = acpi_root_handle_to_bridge(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 (!bridge) {
    + handle_root_bridge_insertion(handle);
    + add_acpi_root_bridge(handle);
    + }
    +
    + break;
    +
    + case ACPI_NOTIFY_DEVICE_CHECK:
    + /* device check */
    + printk(KERN_DEBUG "%s: Device check notify on %s\n", __func__,
    + objname);
    + if (!bridge) {
    + handle_root_bridge_insertion(handle);
    + add_acpi_root_bridge(handle);
    + }
    + 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_root_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);
    +
    + add_acpi_root_bridge(handle);
    +
    + 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);
    --
    1.7.7


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