[PATCH 16/140] ACPI: use PNPID:instance_no as bus_id of ACPI device

Len Brown
2007-02-07T18:53:19Z

From: Zhang Rui <rui.zhang@intel.com>

Previously we used the device name in the DSDT, but would
crash upon encountering a duplicate. Also, exposing the
DSDT device name to the user in a patch isn't a good idea,
because it is arbitrary.

After some discussion, we finally decided to use
"PNPID:instance_no" as the bus_id of ACPI devices.

Two attributes for each device are added at the same time,
the full pathname in ACPI namespace and hardware_id if it has.

NOTE: acpi_bus_id_list is used to keep the information of PNPID
and instance number of the given PNPID. Loop the
acpi_bus_id_list to find the instance_no of the same PNPID
when register a device. If failed, i.e. we don't have a
node with this PNPID, allocate one and link it to this list.

NOTE: Now I don't take the memory free work in charge.
If necessary, I can add a reference count in
struct acpi_device_bus_id, and check the reference and
when unregister a device, i.e. memory is freed when
the reference count of a given PNPID is 0.

Signed-off-by: Li Shaohua <shaohua.li@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
---
drivers/acpi/scan.c | 118 +++++++++++++++++++++++++++++++++++++++++++++++----
1 files changed, 109 insertions(+), 9 deletions(-)

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 9efe3e9..769e54b 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -21,9 +21,15 @@ extern struct acpi_device *acpi_root;
#define ACPI_BUS_DEVICE_NAME "System Bus"

static LIST_HEAD(acpi_device_list);
+static LIST_HEAD(acpi_bus_id_list);
DEFINE_SPINLOCK(acpi_device_lock);
LIST_HEAD(acpi_wakeup_device_list);

+struct acpi_device_bus_id{
+ char bus_id[9];
+ unsigned int instance_no;
+ struct list_head node;
+};
static int acpi_eject_operation(acpi_handle handle, int lockable)
{
struct acpi_object_list arg_list;
@@ -103,18 +109,61 @@ acpi_eject_store(struct device *d, struct device_attribute *attr,

static DEVICE_ATTR(eject, 0200, NULL, acpi_eject_store);

-static void acpi_device_setup_files(struct acpi_device *dev)
+static ssize_t
+acpi_device_hid_show(struct device *dev, struct device_attribute *attr, char *buf) {
+ struct acpi_device *acpi_dev = to_acpi_device(dev);
+
+ return sprintf(buf, "%s\n", acpi_dev->pnp.hardware_id);
+}
+static DEVICE_ATTR(hid, 0444, acpi_device_hid_show, NULL);
+
+static ssize_t
+acpi_device_path_show(struct device *dev, struct device_attribute *attr, char *buf) {
+ struct acpi_device *acpi_dev = to_acpi_device(dev);
+ struct acpi_buffer path = {ACPI_ALLOCATE_BUFFER, NULL};
+ int result;
+
+ result = acpi_get_name(acpi_dev->handle, ACPI_FULL_PATHNAME, &path);
+ if(result)
+ goto end;
+
+ result = sprintf(buf, "%s\n", (char*)path.pointer);
+ kfree(path.pointer);
+ end:
+ return result;
+}
+static DEVICE_ATTR(path, 0444, acpi_device_path_show, NULL);
+
+static int acpi_device_setup_files(struct acpi_device *dev)
{
acpi_status status;
acpi_handle temp;
+ int result = 0;

/*
- * If device has _EJ0, 'eject' file is created that is used to trigger
- * hot-removal function from userland.
+ * Devices gotten from FADT don't have a "path" attribute
*/
+ if(dev->handle) {
+ result = device_create_file(&dev->dev, &dev_attr_path);
+ if(result)
+ goto end;
+ }
+
+ if(dev->flags.hardware_id) {
+ result = device_create_file(&dev->dev, &dev_attr_hid);
+ if(result)
+ goto end;
+ }
+
+ /*
+ * If device has _EJ0, 'eject' file is created that is used to trigger
+ * hot-removal function from userland.
+ */
status = acpi_get_handle(dev->handle, "_EJ0", &temp);
if (ACPI_SUCCESS(status))
- device_create_file(&dev->dev, &dev_attr_eject);
+ result = device_create_file(&dev->dev, &dev_attr_eject);
+ end:
+ return result;
}

static void acpi_device_remove_files(struct acpi_device *dev)
@@ -129,6 +178,11 @@ static void acpi_device_remove_files(struct acpi_device *dev)
status = acpi_get_handle(dev->handle, "_EJ0", &temp);
if (ACPI_SUCCESS(status))
device_remove_file(&dev->dev, &dev_attr_eject);
+
+ if(dev->flags.hardware_id)
+ device_remove_file(&dev->dev, &dev_attr_hid);
+ if(dev->handle)
+ device_remove_file(&dev->dev, &dev_attr_path);
}
/* --------------------------------------------------------------------------
ACPI Bus operations
@@ -260,9 +314,12 @@ static struct bus_type acpi_bus_type = {
.uevent = acpi_device_uevent,
};

-static void acpi_device_register(struct acpi_device *device,
+static int acpi_device_register(struct acpi_device *device,
struct acpi_device *parent)
{
+ int result;
+ struct acpi_device_bus_id *acpi_device_bus_id, *new_bus_id;
+ int found = 0;
/*
* Linkage
* -------
@@ -273,7 +330,33 @@ static void acpi_device_register(struct acpi_device *device,
INIT_LIST_HEAD(&device->g_list);
INIT_LIST_HEAD(&device->wakeup_list);

+ new_bus_id = kzalloc(sizeof(struct acpi_device_bus_id), GFP_KERNEL);
+ if (!new_bus_id) {
+ printk(KERN_ERR PREFIX "Memory allocation error\n");
+ return -ENOMEM;
+ }
+
spin_lock(&acpi_device_lock);
+ /*
+ * Find suitable bus_id and instance number in acpi_bus_id_list
+ * If failed, create one and link it into acpi_bus_id_list
+ */
+ list_for_each_entry(acpi_device_bus_id, &acpi_bus_id_list, node) {
+ if(!strcmp(acpi_device_bus_id->bus_id, device->flags.hardware_id? device->pnp.hardware_id : "PNPIDNON")) {
+ acpi_device_bus_id->instance_no ++;
+ found = 1;
+ kfree(new_bus_id);
+ break;
+ }
+ }
+ if(!found) {
+ acpi_device_bus_id = new_bus_id;
+ strcpy(acpi_device_bus_id->bus_id, device->flags.hardware_id ? device->pnp.hardware_id : "PNPIDNON");
+ acpi_device_bus_id->instance_no = 0;
+ list_add_tail(&acpi_device_bus_id->node, &acpi_bus_id_list);
+ }
+ sprintf(device->dev.bus_id, "%s:%02x", acpi_device_bus_id->bus_id, acpi_device_bus_id->instance_no);
+
if (device->parent) {
list_add_tail(&device->node, &device->parent->children);
list_add_tail(&device->g_list, &device->parent->g_list);
@@ -287,12 +370,29 @@ static void acpi_device_register(struct acpi_device *device,
device->dev.parent = &parent->dev;
device->dev.bus = &acpi_bus_type;
device_initialize(&device->dev);
- sprintf(device->dev.bus_id, "%s", device->pnp.bus_id);
device->dev.release = &acpi_device_release;
- device_add(&device->dev);
+ result = device_add(&device->dev);
+ if(result) {
+ printk("Error adding device %s", device->dev.bus_id);
+ goto end;
+ }
+
+ result = acpi_device_setup_files(device);
+ if(result)
+ ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Error creating sysfs interface for device %s\n", device->dev.bus_id));

- acpi_device_setup_files(device);
device->removal_type = ACPI_BUS_REMOVAL_NORMAL;
+ return 0;
+ end:
+ spin_lock(&acpi_device_lock);
+ if (device->parent) {
+ list_del(&device->node);
+ list_del(&device->g_list);
+ } else
+ list_del(&device->g_list);
+ list_del(&device->wakeup_list);
+ spin_unlock(&acpi_device_lock);
+ return result;
}

static void acpi_device_unregister(struct acpi_device *device, int type)
@@ -1035,7 +1135,7 @@ acpi_add_single_object(struct acpi_device **child,

acpi_device_get_debug_info(device, handle, type);

- acpi_device_register(device, parent);
+ result = acpi_device_register(device, parent);

end:
if (!result)
--
1.5.0.rc3.39.gec804