hwmon: (fschmd) Add watchdog support
This patch adds support for the watchdog part found in _all_ supported FSC
sensor chips.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
diff --git a/drivers/hwmon/fschmd.c b/drivers/hwmon/fschmd.c
index c188b71..8bb1a44 100644
--- a/drivers/hwmon/fschmd.c
+++ b/drivers/hwmon/fschmd.c
@@ -42,11 +42,20 @@
#include <linux/mutex.h>
#include <linux/sysfs.h>
#include <linux/dmi.h>
+#include <linux/fs.h>
+#include <linux/watchdog.h>
+#include <linux/miscdevice.h>
+#include <linux/uaccess.h>
+#include <linux/kref.h>
/* Addresses to scan */
static const unsigned short normal_i2c[] = { 0x73, I2C_CLIENT_END };
/* Insmod parameters */
+static int nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, int, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
+ __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
I2C_CLIENT_INSMOD_5(fscpos, fscher, fscscy, fschrc, fschmd);
/*
@@ -65,11 +74,18 @@
#define FSCHMD_CONTROL_ALERT_LED 0x01
-/* watchdog (support to be implemented) */
+/* watchdog */
#define FSCHMD_REG_WDOG_PRESET 0x28
#define FSCHMD_REG_WDOG_STATE 0x23
#define FSCHMD_REG_WDOG_CONTROL 0x21
+#define FSCHMD_WDOG_CONTROL_TRIGGER 0x10
+#define FSCHMD_WDOG_CONTROL_STARTED 0x10 /* the same as trigger */
+#define FSCHMD_WDOG_CONTROL_STOP 0x20
+#define FSCHMD_WDOG_CONTROL_RESOLUTION 0x40
+
+#define FSCHMD_WDOG_STATE_CARDRESET 0x02
+
/* voltages, weird order is to keep the same order as the old drivers */
static const u8 FSCHMD_REG_VOLT[3] = { 0x45, 0x42, 0x48 };
@@ -206,14 +222,26 @@
*/
struct fschmd_data {
+ struct i2c_client *client;
struct device *hwmon_dev;
struct mutex update_lock;
+ struct mutex watchdog_lock;
+ struct list_head list; /* member of the watchdog_data_list */
+ struct kref kref;
+ struct miscdevice watchdog_miscdev;
int kind;
+ unsigned long watchdog_is_open;
+ char watchdog_expect_close;
+ char watchdog_name[10]; /* must be unique to avoid sysfs conflict */
char valid; /* zero until following fields are valid */
unsigned long last_updated; /* in jiffies */
/* register values */
+ u8 revision; /* chip revision */
u8 global_control; /* global control register */
+ u8 watchdog_control; /* watchdog control register */
+ u8 watchdog_state; /* watchdog status register */
+ u8 watchdog_preset; /* watchdog counter preset on trigger val */
u8 volt[3]; /* 12, 5, battery voltage */
u8 temp_act[5]; /* temperature */
u8 temp_status[5]; /* status of sensor */
@@ -225,11 +253,28 @@
};
/* Global variables to hold information read from special DMI tables, which are
- available on FSC machines with an fscher or later chip. */
+ available on FSC machines with an fscher or later chip. There is no need to
+ protect these with a lock as they are only modified from our attach function
+ which always gets called with the i2c-core lock held and never accessed
+ before the attach function is done with them. */
static int dmi_mult[3] = { 490, 200, 100 };
static int dmi_offset[3] = { 0, 0, 0 };
static int dmi_vref = -1;
+/* Somewhat ugly :( global data pointer list with all fschmd devices, so that
+ we can find our device data as when using misc_register there is no other
+ method to get to ones device data from the open fop. */
+static LIST_HEAD(watchdog_data_list);
+/* Note this lock not only protect list access, but also data.kref access */
+static DEFINE_MUTEX(watchdog_data_mutex);
+
+/* Release our data struct when we're detached from the i2c client *and* all
+ references to our watchdog device are released */
+static void fschmd_release_resources(struct kref *ref)
+{
+ struct fschmd_data *data = container_of(ref, struct fschmd_data, kref);
+ kfree(data);
+}
/*
* Sysfs attr show / store functions
@@ -548,7 +593,265 @@
/*
- * Real code
+ * Watchdog routines
+ */
+
+static int watchdog_set_timeout(struct fschmd_data *data, int timeout)
+{
+ int ret, resolution;
+ int kind = data->kind + 1; /* 0-x array index -> 1-x module param */
+
+ /* 2 second or 60 second resolution? */
+ if (timeout <= 510 || kind == fscpos || kind == fscscy)
+ resolution = 2;
+ else
+ resolution = 60;
+
+ if (timeout < resolution || timeout > (resolution * 255))
+ return -EINVAL;
+
+ mutex_lock(&data->watchdog_lock);
+ if (!data->client) {
+ ret = -ENODEV;
+ goto leave;
+ }
+
+ if (resolution == 2)
+ data->watchdog_control &= ~FSCHMD_WDOG_CONTROL_RESOLUTION;
+ else
+ data->watchdog_control |= FSCHMD_WDOG_CONTROL_RESOLUTION;
+
+ data->watchdog_preset = DIV_ROUND_UP(timeout, resolution);
+
+ /* Write new timeout value */
+ i2c_smbus_write_byte_data(data->client, FSCHMD_REG_WDOG_PRESET,
+ data->watchdog_preset);
+ /* Write new control register, do not trigger! */
+ i2c_smbus_write_byte_data(data->client, FSCHMD_REG_WDOG_CONTROL,
+ data->watchdog_control & ~FSCHMD_WDOG_CONTROL_TRIGGER);
+
+ ret = data->watchdog_preset * resolution;
+
+leave:
+ mutex_unlock(&data->watchdog_lock);
+ return ret;
+}
+
+static int watchdog_get_timeout(struct fschmd_data *data)
+{
+ int timeout;
+
+ mutex_lock(&data->watchdog_lock);
+ if (data->watchdog_control & FSCHMD_WDOG_CONTROL_RESOLUTION)
+ timeout = data->watchdog_preset * 60;
+ else
+ timeout = data->watchdog_preset * 2;
+ mutex_unlock(&data->watchdog_lock);
+
+ return timeout;
+}
+
+static int watchdog_trigger(struct fschmd_data *data)
+{
+ int ret = 0;
+
+ mutex_lock(&data->watchdog_lock);
+ if (!data->client) {
+ ret = -ENODEV;
+ goto leave;
+ }
+
+ data->watchdog_control |= FSCHMD_WDOG_CONTROL_TRIGGER;
+ i2c_smbus_write_byte_data(data->client, FSCHMD_REG_WDOG_CONTROL,
+ data->watchdog_control);
+leave:
+ mutex_unlock(&data->watchdog_lock);
+ return ret;
+}
+
+static int watchdog_stop(struct fschmd_data *data)
+{
+ int ret = 0;
+
+ mutex_lock(&data->watchdog_lock);
+ if (!data->client) {
+ ret = -ENODEV;
+ goto leave;
+ }
+
+ data->watchdog_control &= ~FSCHMD_WDOG_CONTROL_STARTED;
+ /* Don't store the stop flag in our watchdog control register copy, as
+ its a write only bit (read always returns 0) */
+ i2c_smbus_write_byte_data(data->client, FSCHMD_REG_WDOG_CONTROL,
+ data->watchdog_control | FSCHMD_WDOG_CONTROL_STOP);
+leave:
+ mutex_unlock(&data->watchdog_lock);
+ return ret;
+}
+
+static int watchdog_open(struct inode *inode, struct file *filp)
+{
+ struct fschmd_data *pos, *data = NULL;
+
+ /* We get called from drivers/char/misc.c with misc_mtx hold, and we
+ call misc_register() from fschmd_probe() with watchdog_data_mutex
+ hold, as misc_register() takes the misc_mtx lock, this is a possible
+ deadlock, so we use mutex_trylock here. */
+ if (!mutex_trylock(&watchdog_data_mutex))
+ return -ERESTARTSYS;
+ list_for_each_entry(pos, &watchdog_data_list, list) {
+ if (pos->watchdog_miscdev.minor == iminor(inode)) {
+ data = pos;
+ break;
+ }
+ }
+ /* Note we can never not have found data, so we don't check for this */
+ kref_get(&data->kref);
+ mutex_unlock(&watchdog_data_mutex);
+
+ if (test_and_set_bit(0, &data->watchdog_is_open))
+ return -EBUSY;
+
+ /* Start the watchdog */
+ watchdog_trigger(data);
+ filp->private_data = data;
+
+ return nonseekable_open(inode, filp);
+}
+
+static int watchdog_release(struct inode *inode, struct file *filp)
+{
+ struct fschmd_data *data = filp->private_data;
+
+ if (data->watchdog_expect_close) {
+ watchdog_stop(data);
+ data->watchdog_expect_close = 0;
+ } else {
+ watchdog_trigger(data);
+ dev_crit(&data->client->dev,
+ "unexpected close, not stopping watchdog!\n");
+ }
+
+ clear_bit(0, &data->watchdog_is_open);
+
+ mutex_lock(&watchdog_data_mutex);
+ kref_put(&data->kref, fschmd_release_resources);
+ mutex_unlock(&watchdog_data_mutex);
+
+ return 0;
+}
+
+static ssize_t watchdog_write(struct file *filp, const char __user *buf,
+ size_t count, loff_t *offset)
+{
+ size_t ret;
+ struct fschmd_data *data = filp->private_data;
+
+ if (count) {
+ if (!nowayout) {
+ size_t i;
+
+ /* Clear it in case it was set with a previous write */
+ data->watchdog_expect_close = 0;
+
+ for (i = 0; i != count; i++) {
+ char c;
+ if (get_user(c, buf + i))
+ return -EFAULT;
+ if (c == 'V')
+ data->watchdog_expect_close = 1;
+ }
+ }
+ ret = watchdog_trigger(data);
+ if (ret < 0)
+ return ret;
+ }
+ return count;
+}
+
+static int watchdog_ioctl(struct inode *inode, struct file *filp,
+ unsigned int cmd, unsigned long arg)
+{
+ static struct watchdog_info ident = {
+ .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
+ WDIOF_CARDRESET,
+ .identity = "FSC watchdog"
+ };
+ int i, ret = 0;
+ struct fschmd_data *data = filp->private_data;
+
+ switch (cmd) {
+ case WDIOC_GETSUPPORT:
+ ident.firmware_version = data->revision;
+ if (!nowayout)
+ ident.options |= WDIOF_MAGICCLOSE;
+ if (copy_to_user((void __user *)arg, &ident, sizeof(ident)))
+ ret = -EFAULT;
+ break;
+
+ case WDIOC_GETSTATUS:
+ ret = put_user(0, (int __user *)arg);
+ break;
+
+ case WDIOC_GETBOOTSTATUS:
+ if (data->watchdog_state & FSCHMD_WDOG_STATE_CARDRESET)
+ ret = put_user(WDIOF_CARDRESET, (int __user *)arg);
+ else
+ ret = put_user(0, (int __user *)arg);
+ break;
+
+ case WDIOC_KEEPALIVE:
+ ret = watchdog_trigger(data);
+ break;
+
+ case WDIOC_GETTIMEOUT:
+ i = watchdog_get_timeout(data);
+ ret = put_user(i, (int __user *)arg);
+ break;
+
+ case WDIOC_SETTIMEOUT:
+ if (get_user(i, (int __user *)arg)) {
+ ret = -EFAULT;
+ break;
+ }
+ ret = watchdog_set_timeout(data, i);
+ if (ret > 0)
+ ret = put_user(ret, (int __user *)arg);
+ break;
+
+ case WDIOC_SETOPTIONS:
+ if (get_user(i, (int __user *)arg)) {
+ ret = -EFAULT;
+ break;
+ }
+
+ if (i & WDIOS_DISABLECARD)
+ ret = watchdog_stop(data);
+ else if (i & WDIOS_ENABLECARD)
+ ret = watchdog_trigger(data);
+ else
+ ret = -EINVAL;
+
+ break;
+ default:
+ ret = -ENOTTY;
+ }
+
+ return ret;
+}
+
+static struct file_operations watchdog_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .open = watchdog_open,
+ .release = watchdog_release,
+ .write = watchdog_write,
+ .ioctl = watchdog_ioctl,
+};
+
+
+/*
+ * Detect, register, unregister and update device functions
*/
/* DMI decode routine to read voltage scaling factors from special DMI tables,
@@ -658,9 +961,9 @@
const struct i2c_device_id *id)
{
struct fschmd_data *data;
- u8 revision;
const char * const names[5] = { "Poseidon", "Hermes", "Scylla",
"Heracles", "Heimdall" };
+ const int watchdog_minors[] = { WATCHDOG_MINOR, 212, 213, 214, 215 };
int i, err;
enum chips kind = id->driver_data;
@@ -670,6 +973,13 @@
i2c_set_clientdata(client, data);
mutex_init(&data->update_lock);
+ mutex_init(&data->watchdog_lock);
+ INIT_LIST_HEAD(&data->list);
+ kref_init(&data->kref);
+ /* Store client pointer in our data struct for watchdog usage
+ (where the client is found through a data ptr instead of the
+ otherway around) */
+ data->client = client;
if (kind == fscpos) {
/* The Poseidon has hardwired temp limits, fill these
@@ -690,6 +1000,17 @@
}
}
+ /* Read in some never changing registers */
+ data->revision = i2c_smbus_read_byte_data(client, FSCHMD_REG_REVISION);
+ data->global_control = i2c_smbus_read_byte_data(client,
+ FSCHMD_REG_CONTROL);
+ data->watchdog_control = i2c_smbus_read_byte_data(client,
+ FSCHMD_REG_WDOG_CONTROL);
+ data->watchdog_state = i2c_smbus_read_byte_data(client,
+ FSCHMD_REG_WDOG_STATE);
+ data->watchdog_preset = i2c_smbus_read_byte_data(client,
+ FSCHMD_REG_WDOG_PRESET);
+
/* i2c kind goes from 1-5, we want from 0-4 to address arrays */
data->kind = kind - 1;
@@ -732,9 +1053,43 @@
goto exit_detach;
}
- revision = i2c_smbus_read_byte_data(client, FSCHMD_REG_REVISION);
+ /* We take the data_mutex lock early so that watchdog_open() cannot
+ run when misc_register() has completed, but we've not yet added
+ our data to the watchdog_data_list (and set the default timeout) */
+ mutex_lock(&watchdog_data_mutex);
+ for (i = 0; i < ARRAY_SIZE(watchdog_minors); i++) {
+ /* Register our watchdog part */
+ snprintf(data->watchdog_name, sizeof(data->watchdog_name),
+ "watchdog%c", (i == 0) ? '\0' : ('0' + i));
+ data->watchdog_miscdev.name = data->watchdog_name;
+ data->watchdog_miscdev.fops = &watchdog_fops;
+ data->watchdog_miscdev.minor = watchdog_minors[i];
+ err = misc_register(&data->watchdog_miscdev);
+ if (err == -EBUSY)
+ continue;
+ if (err) {
+ data->watchdog_miscdev.minor = 0;
+ dev_err(&client->dev,
+ "Registering watchdog chardev: %d\n", err);
+ break;
+ }
+
+ list_add(&data->list, &watchdog_data_list);
+ watchdog_set_timeout(data, 60);
+ dev_info(&client->dev,
+ "Registered watchdog chardev major 10, minor: %d\n",
+ watchdog_minors[i]);
+ break;
+ }
+ if (i == ARRAY_SIZE(watchdog_minors)) {
+ data->watchdog_miscdev.minor = 0;
+ dev_warn(&client->dev, "Couldn't register watchdog chardev "
+ "(due to no free minor)\n");
+ }
+ mutex_unlock(&watchdog_data_mutex);
+
dev_info(&client->dev, "Detected FSC %s chip, revision: %d\n",
- names[data->kind], (int) revision);
+ names[data->kind], (int) data->revision);
return 0;
@@ -748,6 +1103,24 @@
struct fschmd_data *data = i2c_get_clientdata(client);
int i;
+ /* Unregister the watchdog (if registered) */
+ if (data->watchdog_miscdev.minor) {
+ misc_deregister(&data->watchdog_miscdev);
+ if (data->watchdog_is_open) {
+ dev_warn(&client->dev,
+ "i2c client detached with watchdog open! "
+ "Stopping watchdog.\n");
+ watchdog_stop(data);
+ }
+ mutex_lock(&watchdog_data_mutex);
+ list_del(&data->list);
+ mutex_unlock(&watchdog_data_mutex);
+ /* Tell the watchdog code the client is gone */
+ mutex_lock(&data->watchdog_lock);
+ data->client = NULL;
+ mutex_unlock(&data->watchdog_lock);
+ }
+
/* Check if registered in case we're called from fschmd_detect
to cleanup after an error */
if (data->hwmon_dev)
@@ -762,7 +1135,10 @@
device_remove_file(&client->dev,
&fschmd_fan_attr[i].dev_attr);
- kfree(data);
+ mutex_lock(&watchdog_data_mutex);
+ kref_put(&data->kref, fschmd_release_resources);
+ mutex_unlock(&watchdog_data_mutex);
+
return 0;
}
@@ -824,17 +1200,6 @@
data->volt[i] = i2c_smbus_read_byte_data(client,
FSCHMD_REG_VOLT[i]);
- data->global_control = i2c_smbus_read_byte_data(client,
- FSCHMD_REG_CONTROL);
-
- /* To be implemented in the future
- data->watchdog[0] = i2c_smbus_read_byte_data(client,
- FSCHMD_REG_WDOG_PRESET);
- data->watchdog[1] = i2c_smbus_read_byte_data(client,
- FSCHMD_REG_WDOG_STATE);
- data->watchdog[2] = i2c_smbus_read_byte_data(client,
- FSCHMD_REG_WDOG_CONTROL); */
-
data->last_updated = jiffies;
data->valid = 1;
}