[PATCH v3 2/4] hwmon: (asus-ec-sensors) implement locking via the ACPI global lock
From: Eugene Shalygin
Date: Wed Apr 27 2022 - 10:30:33 EST
For some board models ASUS uses the global ACPI lock to guard access to
the hardware, so do we.
Signed-off-by: Eugene Shalygin <eugene.shalygin@xxxxxxxxx>
---
Documentation/hwmon/asus_ec_sensors.rst | 2 +
drivers/hwmon/asus-ec-sensors.c | 125 +++++++++++++++++++-----
2 files changed, 101 insertions(+), 26 deletions(-)
diff --git a/Documentation/hwmon/asus_ec_sensors.rst b/Documentation/hwmon/asus_ec_sensors.rst
index b3469851ab9a..36ca531d32dd 100644
--- a/Documentation/hwmon/asus_ec_sensors.rst
+++ b/Documentation/hwmon/asus_ec_sensors.rst
@@ -53,3 +53,5 @@ Module Parameters
the path is mostly identical for them). If ASUS changes this path
in a future BIOS update, this parameter can be used to override
the stored in the driver value until it gets updated.
+ A special string ":GLOBAL_LOCK" can be passed to use the ACPI
+ global lock instead of a dedicated mutex.
diff --git a/drivers/hwmon/asus-ec-sensors.c b/drivers/hwmon/asus-ec-sensors.c
index 0c82723f85b5..581df4053060 100644
--- a/drivers/hwmon/asus-ec-sensors.c
+++ b/drivers/hwmon/asus-ec-sensors.c
@@ -56,6 +56,9 @@ static char *mutex_path_override;
#define MAX_IDENTICAL_BOARD_VARIATIONS 2
+/* Moniker for the ACPI global lock (':' is not allowed in ASL identifiers) */
+#define ACPI_GLOBAL_LOCK_PSEUDO_PATH ":GLOBAL_LOCK"
+
typedef union {
u32 value;
struct {
@@ -166,6 +169,14 @@ static const struct ec_sensor_info known_ec_sensors[] = {
struct ec_board_info {
const char *board_names[MAX_IDENTICAL_BOARD_VARIATIONS];
unsigned long sensors;
+ /*
+ * Defines which mutex to use for guarding access to the state and the
+ * hardware. Can be either a full path to an AML mutex or the
+ * pseudo-path ACPI_GLOBAL_LOCK_PSEUDO_PATH to use the global ACPI lock,
+ * or left empty to use a regular mutex object, in which case access to
+ * the hardware is not guarded.
+ */
+ const char *mutex_path;
};
static const struct ec_board_info board_info[] = {
@@ -173,6 +184,7 @@ static const struct ec_board_info board_info[] = {
.board_names = {"PRIME X570-PRO"},
.sensors = SENSOR_SET_TEMP_CHIPSET_CPU_MB | SENSOR_TEMP_VRM |
SENSOR_TEMP_T_SENSOR | SENSOR_FAN_CHIPSET,
+ .mutex_path = ASUS_HW_ACCESS_MUTEX_ASMX,
},
{
.board_names = {"ProArt X570-CREATOR WIFI"},
@@ -185,6 +197,7 @@ static const struct ec_board_info board_info[] = {
.sensors = SENSOR_SET_TEMP_CHIPSET_CPU_MB | SENSOR_TEMP_VRM |
SENSOR_TEMP_T_SENSOR | SENSOR_FAN_CHIPSET |
SENSOR_CURR_CPU | SENSOR_IN_CPU_CORE,
+ .mutex_path = ASUS_HW_ACCESS_MUTEX_ASMX,
},
{
.board_names = {"ROG CROSSHAIR VIII DARK HERO"},
@@ -193,6 +206,7 @@ static const struct ec_board_info board_info[] = {
SENSOR_TEMP_VRM | SENSOR_SET_TEMP_WATER |
SENSOR_FAN_CPU_OPT | SENSOR_FAN_WATER_FLOW |
SENSOR_CURR_CPU | SENSOR_IN_CPU_CORE,
+ .mutex_path = ASUS_HW_ACCESS_MUTEX_ASMX,
},
{
.board_names = {"ROG CROSSHAIR VIII FORMULA"},
@@ -200,6 +214,7 @@ static const struct ec_board_info board_info[] = {
SENSOR_TEMP_T_SENSOR | SENSOR_TEMP_VRM |
SENSOR_FAN_CPU_OPT | SENSOR_FAN_CHIPSET |
SENSOR_CURR_CPU | SENSOR_IN_CPU_CORE,
+ .mutex_path = ASUS_HW_ACCESS_MUTEX_ASMX,
},
{
.board_names = {
@@ -212,6 +227,7 @@ static const struct ec_board_info board_info[] = {
SENSOR_FAN_CPU_OPT | SENSOR_FAN_CHIPSET |
SENSOR_FAN_WATER_FLOW | SENSOR_CURR_CPU |
SENSOR_IN_CPU_CORE,
+ .mutex_path = ASUS_HW_ACCESS_MUTEX_ASMX,
},
{
.board_names = {"ROG CROSSHAIR VIII IMPACT"},
@@ -219,12 +235,14 @@ static const struct ec_board_info board_info[] = {
SENSOR_TEMP_T_SENSOR | SENSOR_TEMP_VRM |
SENSOR_FAN_CHIPSET | SENSOR_CURR_CPU |
SENSOR_IN_CPU_CORE,
+ .mutex_path = ASUS_HW_ACCESS_MUTEX_ASMX,
},
{
.board_names = {"ROG STRIX B550-E GAMING"},
.sensors = SENSOR_SET_TEMP_CHIPSET_CPU_MB |
SENSOR_TEMP_T_SENSOR | SENSOR_TEMP_VRM |
SENSOR_FAN_CPU_OPT,
+ .mutex_path = ASUS_HW_ACCESS_MUTEX_ASMX,
},
{
.board_names = {"ROG STRIX B550-I GAMING"},
@@ -232,6 +250,7 @@ static const struct ec_board_info board_info[] = {
SENSOR_TEMP_T_SENSOR | SENSOR_TEMP_VRM |
SENSOR_FAN_VRM_HS | SENSOR_CURR_CPU |
SENSOR_IN_CPU_CORE,
+ .mutex_path = ASUS_HW_ACCESS_MUTEX_ASMX,
},
{
.board_names = {"ROG STRIX X570-E GAMING"},
@@ -239,17 +258,20 @@ static const struct ec_board_info board_info[] = {
SENSOR_TEMP_T_SENSOR | SENSOR_TEMP_VRM |
SENSOR_FAN_CHIPSET | SENSOR_CURR_CPU |
SENSOR_IN_CPU_CORE,
+ .mutex_path = ASUS_HW_ACCESS_MUTEX_ASMX,
},
{
.board_names = {"ROG STRIX X570-F GAMING"},
.sensors = SENSOR_SET_TEMP_CHIPSET_CPU_MB |
SENSOR_TEMP_T_SENSOR | SENSOR_FAN_CHIPSET,
+ .mutex_path = ASUS_HW_ACCESS_MUTEX_ASMX,
},
{
.board_names = {"ROG STRIX X570-I GAMING"},
.sensors = SENSOR_TEMP_T_SENSOR | SENSOR_FAN_VRM_HS |
SENSOR_FAN_CHIPSET | SENSOR_CURR_CPU |
SENSOR_IN_CPU_CORE,
+ .mutex_path = ASUS_HW_ACCESS_MUTEX_ASMX,
},
{}
};
@@ -259,6 +281,46 @@ struct ec_sensor {
s32 cached_value;
};
+struct lock_data {
+ union {
+ acpi_handle aml;
+ /* global lock handle */
+ u32 glk;
+ } mutex;
+ bool (*lock)(struct lock_data *data);
+ bool (*unlock)(struct lock_data *data);
+};
+
+/*
+ * The next function pairs implement options for locking access to the
+ * state and the EC
+ */
+static bool lock_via_acpi_mutex(struct lock_data *data)
+{
+ /*
+ * ASUS DSDT does not specify that access to the EC has to be guarded,
+ * but firmware does access it via ACPI
+ */
+ return ACPI_SUCCESS(acpi_acquire_mutex(data->mutex.aml,
+ NULL, ACPI_LOCK_DELAY_MS));
+}
+
+static bool unlock_acpi_mutex(struct lock_data *data)
+{
+ return ACPI_SUCCESS(acpi_release_mutex(data->mutex.aml, NULL));
+}
+
+static bool lock_via_global_acpi_lock(struct lock_data *data)
+{
+ return ACPI_SUCCESS(acpi_acquire_global_lock(ACPI_LOCK_DELAY_MS,
+ &data->mutex.glk));
+}
+
+static bool unlock_global_acpi_lock(struct lock_data *data)
+{
+ return ACPI_SUCCESS(acpi_release_global_lock(data->mutex.glk));
+}
+
struct ec_sensors_data {
const struct ec_board_info *board_info;
struct ec_sensor *sensors;
@@ -269,7 +331,7 @@ struct ec_sensors_data {
u8 banks[ASUS_EC_MAX_BANK + 1];
/* in jiffies */
unsigned long last_updated;
- acpi_handle aml_mutex;
+ struct lock_data lock_data;
/* number of board EC sensors */
u8 nr_sensors;
/*
@@ -373,23 +435,36 @@ static void __init fill_ec_registers(struct ec_sensors_data *ec)
}
}
-static acpi_handle __init asus_hw_access_mutex(struct device *dev)
+static int __init setup_lock_data(struct device *dev)
{
const char *mutex_path;
- acpi_handle res;
int status;
+ struct ec_sensors_data *state = dev_get_drvdata(dev);
mutex_path = mutex_path_override ?
- mutex_path_override : ASUS_HW_ACCESS_MUTEX_ASMX;
+ mutex_path_override : state->board_info->mutex_path;
- status = acpi_get_handle(NULL, (acpi_string)mutex_path, &res);
- if (ACPI_FAILURE(status)) {
- dev_err(dev,
- "Could not get hardware access guard mutex '%s': error %d",
- mutex_path, status);
- return NULL;
+ if (!mutex_path || !strlen(mutex_path)) {
+ dev_err(dev, "Hardware access guard mutex name is empty");
+ return -EINVAL;
}
- return res;
+ if (!strcmp(mutex_path, ACPI_GLOBAL_LOCK_PSEUDO_PATH)) {
+ state->lock_data.mutex.glk = 0;
+ state->lock_data.lock = lock_via_global_acpi_lock;
+ state->lock_data.unlock = unlock_global_acpi_lock;
+ } else {
+ status = acpi_get_handle(NULL, (acpi_string)mutex_path,
+ &state->lock_data.mutex.aml);
+ if (ACPI_FAILURE(status)) {
+ dev_err(dev,
+ "Failed to get hardware access guard AML mutex '%s': error %d",
+ mutex_path, status);
+ return -ENOENT;
+ }
+ state->lock_data.lock = lock_via_acpi_mutex;
+ state->lock_data.unlock = unlock_acpi_mutex;
+ }
+ return 0;
}
static int asus_ec_bank_switch(u8 bank, u8 *old)
@@ -492,15 +567,9 @@ static int update_ec_sensors(const struct device *dev,
{
int status;
- /*
- * ASUS DSDT does not specify that access to the EC has to be guarded,
- * but firmware does access it via ACPI
- */
- if (ACPI_FAILURE(acpi_acquire_mutex(ec->aml_mutex, NULL,
- ACPI_LOCK_DELAY_MS))) {
- dev_err(dev, "Failed to acquire AML mutex");
- status = -EBUSY;
- goto cleanup;
+ if (!ec->lock_data.lock(&ec->lock_data)) {
+ dev_warn(dev, "Failed to acquire mutex");
+ return -EBUSY;
}
status = asus_ec_block_read(dev, ec);
@@ -508,10 +577,10 @@ static int update_ec_sensors(const struct device *dev,
if (!status) {
update_sensor_values(ec, ec->read_buffer);
}
- if (ACPI_FAILURE(acpi_release_mutex(ec->aml_mutex, NULL))) {
- dev_err(dev, "Failed to release AML mutex");
- }
-cleanup:
+
+ if (!ec->lock_data.unlock(&ec->lock_data))
+ dev_err(dev, "Failed to release mutex");
+
return status;
}
@@ -651,6 +720,7 @@ static int __init asus_ec_probe(struct platform_device *pdev)
enum hwmon_sensor_types type;
struct device *hwdev;
unsigned int i;
+ int status;
pboard_info = get_board_info();
if (!pboard_info)
@@ -667,6 +737,11 @@ static int __init asus_ec_probe(struct platform_device *pdev)
ec_data->sensors = devm_kcalloc(dev, ec_data->nr_sensors,
sizeof(struct ec_sensor), GFP_KERNEL);
+ status = setup_lock_data(dev);
+ if (status) {
+ dev_err(dev, "Failed to setup state/EC locking: %d", status);
+ return status;
+ }
setup_sensor_data(ec_data);
ec_data->registers = devm_kcalloc(dev, ec_data->nr_registers,
sizeof(u16), GFP_KERNEL);
@@ -678,8 +753,6 @@ static int __init asus_ec_probe(struct platform_device *pdev)
fill_ec_registers(ec_data);
- ec_data->aml_mutex = asus_hw_access_mutex(dev);
-
for (i = 0; i < ec_data->nr_sensors; ++i) {
si = get_sensor_info(ec_data, i);
if (!nr_count[si->type])
--
2.35.1