ACPI 5.0 introduces _DEP to designate device objects that OSPM should
assign a higher priority in start ordering due to future operation region
accesses.
On Asus T100TA, ACPI battery info are read from a I2C slave device via
I2C operation region. Before I2C operation region handler is installed,
battery _STA always returns 0. There is a _DEP method of designating
start order under battery device node.
This patch is to implement _DEP feature to fix battery issue on the Asus T100TA.
Introducing acpi_bus_dep_device_list and adding dep_present flags in the struct
acpi_device. During ACPI namespace scan, all devices with _DEP support will be put
into the new list and those devices' dep_present flag will be set. Driver's probe()
should return EPROBE_DEFER when find dep_present is set. When I2C operation
region handler is installed, check all devices on the new list. Remove the one from
list if _DEP condition is met and clear its dep_present flag and do acpi_bus_attch()
for the device in order to resolve battery _STA issue on the Asus T100TA.
Signed-off-by: Lan Tianyu <tianyu.lan@xxxxxxxxx>
---
drivers/acpi/battery.c | 4 +++
drivers/acpi/scan.c | 84 +++++++++++++++++++++++++++++++++++++++++++++++++
drivers/i2c/i2c-acpi.c | 1 +
include/acpi/acpi_bus.h | 2 ++
include/linux/acpi.h | 3 ++
5 files changed, 94 insertions(+)
diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
index 1c162e7..c0a68ce 100644
--- a/drivers/acpi/battery.c
+++ b/drivers/acpi/battery.c
@@ -1194,6 +1194,10 @@ static int acpi_battery_add(struct acpi_device *device)
if (!device)
return -EINVAL;
+
+ if (device->dep_present)
+ return -EPROBE_DEFER;
+
battery = kzalloc(sizeof(struct acpi_battery), GFP_KERNEL);
if (!battery)
return -ENOMEM;
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 3bf7764..a26dbb3 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -36,6 +36,7 @@ bool acpi_force_hot_remove;
static const char *dummy_hid = "device";
+static LIST_HEAD(acpi_bus_dep_device_list);
static LIST_HEAD(acpi_bus_id_list);
static DEFINE_MUTEX(acpi_scan_lock);
static LIST_HEAD(acpi_scan_handlers_list);
@@ -43,6 +44,11 @@ DEFINE_MUTEX(acpi_device_lock);
LIST_HEAD(acpi_wakeup_device_list);
static DEFINE_MUTEX(acpi_hp_context_lock);
+struct acpi_dep_data {
+ struct list_head node;
+ struct acpi_device *adev;
+};
+
struct acpi_device_bus_id{
char bus_id[15];
unsigned int instance_no;
@@ -2048,6 +2054,32 @@ static void acpi_scan_init_hotplug(struct acpi_device *adev)
}
}
+static void acpi_device_dep_initialize(struct acpi_device * adev)
+{
+ struct acpi_dep_data *dep;
+ acpi_status status;
+
+ if (!acpi_has_method(adev->handle, "_DEP"))
+ return;
+
+ status = acpi_evaluate_reference(adev->handle, "_DEP", NULL,
+ &adev->dep_devices);
+ if (ACPI_FAILURE(status)) {
+ dev_err(&adev->dev, "Fail to evaluate _DEP.\n");
+ return;
+ }
+
+ dep = kzalloc(sizeof(struct acpi_dep_data), GFP_KERNEL);
+ if (!dep) {
+ dev_err(&adev->dev, "Memory allocation error.\n");
+ return;
+ }
+
+ dep->adev = adev;
+ adev->dep_present = true;
+ list_add_tail(&dep->node , &acpi_bus_dep_device_list);
+}
+
static acpi_status acpi_bus_check_add(acpi_handle handle, u32 lvl_not_used,
void *not_used, void **return_value)
{
@@ -2074,6 +2106,7 @@ static acpi_status acpi_bus_check_add(acpi_handle handle, u32 lvl_not_used,
return AE_CTRL_DEPTH;
acpi_scan_init_hotplug(device);
+ acpi_device_dep_initialize(device);
out:
if (!*return_value)
@@ -2191,6 +2224,57 @@ static void acpi_bus_attach(struct acpi_device *device)
acpi_bus_attach(child);
}
+static int acpi_device_dep_check(struct acpi_device *adev)
+{
+ struct acpi_device *dep_adev;
+ struct acpi_device_physical_node *pn;
+ int i;
+
+ for (i = 0; i < adev->dep_devices.count; i++) {
+ dep_adev = acpi_bus_get_acpi_device(
+ adev->dep_devices.handles[i]);
+
+ if (!dep_adev)
+ return -ENODEV;
+
+ /* Check acpi device driver probing */
+ if (dep_adev->dev.driver)
+ continue;
+
+ if (!dep_adev->physical_node_count)
+ return -ENODEV;
+
+ /* Check physcial device node driver probing */
+ mutex_lock(&dep_adev->physical_node_lock);
+ list_for_each_entry(pn, &dep_adev->physical_node_list, node) {
+ if (pn->dev->driver) {
+ mutex_unlock(&dep_adev->physical_node_lock);
+ continue;
+ }
+ }
+ mutex_unlock(&dep_adev->physical_node_lock);
+ return -EFAULT;
+ }
+
+ return 0;
+}
+
+int acpi_walk_dep_device_list(void)
+{
+ struct acpi_dep_data *dep, *tmp;
+
+ list_for_each_entry_safe(dep, tmp, &acpi_bus_dep_device_list, node) {
+ if (!acpi_device_dep_check(dep->adev)) {
+ dep->adev->dep_present = false;
+ acpi_bus_attach(dep->adev);
+ list_del(&dep->node);
+ kfree(dep);
+ }
+ }
+ return 0;
+}
+EXPORT_SYMBOL_GPL(acpi_walk_dep_device_list);
+
/**
* acpi_bus_scan - Add ACPI device node objects in a given namespace scope.
* @handle: Root of the namespace scope to scan.
diff --git a/drivers/i2c/i2c-acpi.c b/drivers/i2c/i2c-acpi.c
index 0dbc18c..fdc8dc8 100644
--- a/drivers/i2c/i2c-acpi.c
+++ b/drivers/i2c/i2c-acpi.c
@@ -339,6 +339,7 @@ int acpi_i2c_install_space_handler(struct i2c_adapter *adapter)
return -ENOMEM;
}
+ acpi_walk_dep_device_list();
return 0;
}
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index c1c9de1..c1e7055 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -357,7 +357,9 @@ struct acpi_device {
struct acpi_hotplug_context *hp;
struct acpi_driver *driver;
void *driver_data;
+ bool dep_present;
struct device dev;
+ struct acpi_handle_list dep_devices;
unsigned int physical_node_count;
struct list_head physical_node_list;
struct mutex physical_node_lock;
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 807cbc4..c9a504b 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -431,6 +431,7 @@ static inline bool acpi_driver_match_device(struct device *dev,
int acpi_device_uevent_modalias(struct device *, struct kobj_uevent_env *);
int acpi_device_modalias(struct device *, char *, int);
+int acpi_walk_dep_device_list(void);
#define ACPI_PTR(_ptr) (_ptr)
@@ -449,6 +450,8 @@ static inline const char *acpi_dev_name(struct acpi_device *adev)
static inline void acpi_early_init(void) { }
+static inline int acpi_walk_dep_device_list(void) { }
+
static inline int early_acpi_boot_init(void)
{
return 0;
--
1.8.4.rc0.1.g8f6a3e5.dirty
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