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Date: Sun, 27 Mar 2022 14:14:02 +0200
From: Eugene Shalygin <eugene.shalygin@...il.com>
To: eugene.shalygin@...il.com
Cc: darcagn@...tonmail.com, Jean Delvare <jdelvare@...e.com>,
Guenter Roeck <linux@...ck-us.net>,
linux-hwmon@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 2/4] hwmon: (asus-ec-sensors) implement locking via the ACPI global lock
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@...il.com>
---
drivers/hwmon/asus-ec-sensors.c | 143 +++++++++++++++++++++++++-------
1 file changed, 115 insertions(+), 28 deletions(-)
diff --git a/drivers/hwmon/asus-ec-sensors.c b/drivers/hwmon/asus-ec-sensors.c
index 7e28fc62f717..34841eeb800f 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[] __initconst = {
@@ -173,12 +184,14 @@ static const struct ec_board_info board_info[] __initconst = {
.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 = {"Pro WS X570-ACE"},
.sensors = SENSOR_SET_TEMP_CHIPSET_CPU_MB | SENSOR_TEMP_VRM |
SENSOR_FAN_CHIPSET | SENSOR_CURR_CPU |
SENSOR_IN_CPU_CORE,
+ .mutex_path = ASUS_HW_ACCESS_MUTEX_ASMX,
},
{
.board_names = {"ROG CROSSHAIR VIII DARK HERO"},
@@ -187,6 +200,7 @@ static const struct ec_board_info board_info[] __initconst = {
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"},
@@ -194,6 +208,7 @@ static const struct ec_board_info board_info[] __initconst = {
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 = {
@@ -206,6 +221,7 @@ static const struct ec_board_info board_info[] __initconst = {
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"},
@@ -213,12 +229,14 @@ static const struct ec_board_info board_info[] __initconst = {
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"},
@@ -226,6 +244,7 @@ static const struct ec_board_info board_info[] __initconst = {
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"},
@@ -233,17 +252,20 @@ static const struct ec_board_info board_info[] __initconst = {
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,
},
{}
};
@@ -253,6 +275,57 @@ struct ec_sensor {
s32 cached_value;
};
+struct lock_data {
+ union {
+ acpi_handle aml;
+ u32 global_lock_handle;
+ struct mutex regular;
+ } mutex;
+ int (*lock)(struct lock_data *data);
+ int (*unlock)(struct lock_data *data);
+};
+
+/*
+ * The next function pairs implement options for locking access to the
+ * state and the EC
+ */
+static int 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_acquire_mutex(data->mutex.aml, NULL,
+ ACPI_LOCK_DELAY_MS);
+}
+
+static int unlock_acpi_mutex(struct lock_data *data)
+{
+ return acpi_release_mutex(data->mutex.aml, NULL);
+}
+
+static int lock_via_global_acpi_lock(struct lock_data *data)
+{
+ return acpi_acquire_global_lock(ACPI_LOCK_DELAY_MS,
+ &data->mutex.global_lock_handle);
+}
+
+static int unlock_global_acpi_lock(struct lock_data *data)
+{
+ return acpi_release_global_lock(data->mutex.global_lock_handle);
+}
+
+static int lock_via_mutex(struct lock_data *data)
+{
+ return mutex_trylock(&data->mutex.regular) ? 0 : -EBUSY;
+}
+
+static int unlock_mutex(struct lock_data *data)
+{
+ mutex_unlock(&data->mutex.regular);
+ return 0;
+}
+
struct ec_sensors_data {
struct ec_board_info board_info;
struct ec_sensor *sensors;
@@ -263,7 +336,9 @@ 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;
/*
* number of EC registers to read
* (sensor might span more than 1 register)
@@ -370,23 +445,36 @@ 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;
-
- 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;
+ mutex_path_override : state->board_info.mutex_path;
+
+ if (!mutex_path || !strlen(mutex_path)) {
+ mutex_init(&state->lock_data.mutex.regular);
+ state->lock_data.lock = lock_via_mutex;
+ state->lock_data.unlock = unlock_mutex;
+ } else if (!strcmp(mutex_path, ACPI_GLOBAL_LOCK_PSEUDO_PATH)) {
+ 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 res;
+ return 0;
}
static int asus_ec_bank_switch(u8 bank, u8 *old)
@@ -417,7 +505,8 @@ static int asus_ec_block_read(const struct device *dev,
if (prev_bank) {
/* oops... somebody else is working with the EC too */
dev_warn(dev,
- "Concurrent access to the ACPI EC detected.\nRace condition possible.");
+ "Concurrent access to the ACPI EC detected.\n"
+ "Race condition possible.");
}
/* read registers minimizing bank switches. */
@@ -489,15 +578,9 @@ 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);
@@ -505,10 +588,10 @@ 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;
}
@@ -648,6 +731,7 @@ 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)
@@ -663,6 +747,11 @@ static int __init asus_ec_probe(struct platform_device *pdev)
ec_data->sensors = devm_kcalloc(dev, sensor_count(&ec_data->board_info),
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);
@@ -674,8 +763,6 @@ 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 < sensor_count(&ec_data->board_info); ++i) {
si = get_sensor_info(ec_data, i);
if (!nr_count[si->type])
--
2.35.1
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