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Diffstat (limited to 'drivers/w1/w1.c')
-rw-r--r--drivers/w1/w1.c269
1 files changed, 202 insertions, 67 deletions
diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c
index 66efa96c4603..b96f61b15dc6 100644
--- a/drivers/w1/w1.c
+++ b/drivers/w1/w1.c
@@ -46,18 +46,29 @@ MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>");
MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol.");
static int w1_timeout = 10;
-int w1_max_slave_count = 10;
+int w1_max_slave_count = 64;
int w1_max_slave_ttl = 10;
module_param_named(timeout, w1_timeout, int, 0);
+MODULE_PARM_DESC(timeout, "time in seconds between automatic slave searches");
+/* A search stops when w1_max_slave_count devices have been found in that
+ * search. The next search will start over and detect the same set of devices
+ * on a static 1-wire bus. Memory is not allocated based on this number, just
+ * on the number of devices known to the kernel. Having a high number does not
+ * consume additional resources. As a special case, if there is only one
+ * device on the network and w1_max_slave_count is set to 1, the device id can
+ * be read directly skipping the normal slower search process.
+ */
module_param_named(max_slave_count, w1_max_slave_count, int, 0);
+MODULE_PARM_DESC(max_slave_count,
+ "maximum number of slaves detected in a search");
module_param_named(slave_ttl, w1_max_slave_ttl, int, 0);
+MODULE_PARM_DESC(slave_ttl,
+ "Number of searches not seeing a slave before it will be removed");
DEFINE_MUTEX(w1_mlock);
LIST_HEAD(w1_masters);
-static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn);
-
static int w1_master_match(struct device *dev, struct device_driver *drv)
{
return 1;
@@ -81,19 +92,10 @@ static void w1_slave_release(struct device *dev)
{
struct w1_slave *sl = dev_to_w1_slave(dev);
- dev_dbg(dev, "%s: Releasing %s.\n", __func__, sl->name);
-
- while (atomic_read(&sl->refcnt)) {
- dev_dbg(dev, "Waiting for %s to become free: refcnt=%d.\n",
- sl->name, atomic_read(&sl->refcnt));
- if (msleep_interruptible(1000))
- flush_signals(current);
- }
+ dev_dbg(dev, "%s: Releasing %s [%p]\n", __func__, sl->name, sl);
w1_family_put(sl->family);
sl->master->slave_count--;
-
- complete(&sl->released);
}
static ssize_t name_show(struct device *dev, struct device_attribute *attr, char *buf)
@@ -243,7 +245,9 @@ static ssize_t w1_master_attribute_store_search(struct device * dev,
mutex_lock(&md->mutex);
md->search_count = tmp;
mutex_unlock(&md->mutex);
- wake_up_process(md->thread);
+ /* Only wake if it is going to be searching. */
+ if (tmp)
+ wake_up_process(md->thread);
return count;
}
@@ -277,7 +281,6 @@ static ssize_t w1_master_attribute_store_pullup(struct device *dev,
mutex_lock(&md->mutex);
md->enable_pullup = tmp;
mutex_unlock(&md->mutex);
- wake_up_process(md->thread);
return count;
}
@@ -314,6 +317,24 @@ static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct devic
return count;
}
+static ssize_t w1_master_attribute_store_max_slave_count(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ int tmp;
+ struct w1_master *md = dev_to_w1_master(dev);
+
+ if (kstrtoint(buf, 0, &tmp) == -EINVAL || tmp < 1)
+ return -EINVAL;
+
+ mutex_lock(&md->mutex);
+ md->max_slave_count = tmp;
+ /* allow each time the max_slave_count is updated */
+ clear_bit(W1_WARN_MAX_COUNT, &md->flags);
+ mutex_unlock(&md->mutex);
+
+ return count;
+}
+
static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
{
struct w1_master *md = dev_to_w1_master(dev);
@@ -352,23 +373,20 @@ static ssize_t w1_master_attribute_show_slaves(struct device *dev,
{
struct w1_master *md = dev_to_w1_master(dev);
int c = PAGE_SIZE;
+ struct list_head *ent, *n;
+ struct w1_slave *sl = NULL;
- mutex_lock(&md->mutex);
-
- if (md->slave_count == 0)
- c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
- else {
- struct list_head *ent, *n;
- struct w1_slave *sl;
+ mutex_lock(&md->list_mutex);
- list_for_each_safe(ent, n, &md->slist) {
- sl = list_entry(ent, struct w1_slave, w1_slave_entry);
+ list_for_each_safe(ent, n, &md->slist) {
+ sl = list_entry(ent, struct w1_slave, w1_slave_entry);
- c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
- }
+ c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
}
+ if (!sl)
+ c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
- mutex_unlock(&md->mutex);
+ mutex_unlock(&md->list_mutex);
return PAGE_SIZE - c;
}
@@ -422,19 +440,22 @@ static int w1_atoreg_num(struct device *dev, const char *buf, size_t count,
}
/* Searches the slaves in the w1_master and returns a pointer or NULL.
- * Note: must hold the mutex
+ * Note: must not hold list_mutex
*/
-static struct w1_slave *w1_slave_search_device(struct w1_master *dev,
+struct w1_slave *w1_slave_search_device(struct w1_master *dev,
struct w1_reg_num *rn)
{
struct w1_slave *sl;
+ mutex_lock(&dev->list_mutex);
list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
if (sl->reg_num.family == rn->family &&
sl->reg_num.id == rn->id &&
sl->reg_num.crc == rn->crc) {
+ mutex_unlock(&dev->list_mutex);
return sl;
}
}
+ mutex_unlock(&dev->list_mutex);
return NULL;
}
@@ -491,7 +512,10 @@ static ssize_t w1_master_attribute_store_remove(struct device *dev,
mutex_lock(&md->mutex);
sl = w1_slave_search_device(md, &rn);
if (sl) {
- w1_slave_detach(sl);
+ result = w1_slave_detach(sl);
+ /* refcnt 0 means it was detached in the call */
+ if (result == 0)
+ result = count;
} else {
dev_info(dev, "Device %02x-%012llx doesn't exists\n", rn.family,
(unsigned long long)rn.id);
@@ -516,7 +540,7 @@ static ssize_t w1_master_attribute_store_remove(struct device *dev,
static W1_MASTER_ATTR_RO(name, S_IRUGO);
static W1_MASTER_ATTR_RO(slaves, S_IRUGO);
static W1_MASTER_ATTR_RO(slave_count, S_IRUGO);
-static W1_MASTER_ATTR_RO(max_slave_count, S_IRUGO);
+static W1_MASTER_ATTR_RW(max_slave_count, S_IRUGO | S_IWUSR | S_IWGRP);
static W1_MASTER_ATTR_RO(attempts, S_IRUGO);
static W1_MASTER_ATTR_RO(timeout, S_IRUGO);
static W1_MASTER_ATTR_RO(pointer, S_IRUGO);
@@ -686,12 +710,14 @@ static int __w1_attach_slave_device(struct w1_slave *sl)
dev_set_uevent_suppress(&sl->dev, false);
kobject_uevent(&sl->dev.kobj, KOBJ_ADD);
+ mutex_lock(&sl->master->list_mutex);
list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
+ mutex_unlock(&sl->master->list_mutex);
return 0;
}
-static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
+int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
{
struct w1_slave *sl;
struct w1_family *f;
@@ -713,8 +739,8 @@ static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
memset(&msg, 0, sizeof(msg));
memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
- atomic_set(&sl->refcnt, 0);
- init_completion(&sl->released);
+ atomic_set(&sl->refcnt, 1);
+ atomic_inc(&sl->master->refcnt);
/* slave modules need to be loaded in a context with unlocked mutex */
mutex_unlock(&dev->mutex);
@@ -754,23 +780,48 @@ static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
return 0;
}
-void w1_slave_detach(struct w1_slave *sl)
+int w1_unref_slave(struct w1_slave *sl)
{
- struct w1_netlink_msg msg;
-
- dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__, sl->name, sl);
-
- list_del(&sl->w1_slave_entry);
-
- memset(&msg, 0, sizeof(msg));
- memcpy(msg.id.id, &sl->reg_num, sizeof(msg.id));
- msg.type = W1_SLAVE_REMOVE;
- w1_netlink_send(sl->master, &msg);
-
- device_unregister(&sl->dev);
+ struct w1_master *dev = sl->master;
+ int refcnt;
+ mutex_lock(&dev->list_mutex);
+ refcnt = atomic_sub_return(1, &sl->refcnt);
+ if (refcnt == 0) {
+ struct w1_netlink_msg msg;
+
+ dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__,
+ sl->name, sl);
+
+ list_del(&sl->w1_slave_entry);
+
+ memset(&msg, 0, sizeof(msg));
+ memcpy(msg.id.id, &sl->reg_num, sizeof(msg.id));
+ msg.type = W1_SLAVE_REMOVE;
+ w1_netlink_send(sl->master, &msg);
+
+ device_unregister(&sl->dev);
+ #ifdef DEBUG
+ memset(sl, 0, sizeof(*sl));
+ #endif
+ kfree(sl);
+ }
+ atomic_dec(&dev->refcnt);
+ mutex_unlock(&dev->list_mutex);
+ return refcnt;
+}
- wait_for_completion(&sl->released);
- kfree(sl);
+int w1_slave_detach(struct w1_slave *sl)
+{
+ /* Only detach a slave once as it decreases the refcnt each time. */
+ int destroy_now;
+ mutex_lock(&sl->master->list_mutex);
+ destroy_now = !test_bit(W1_SLAVE_DETACH, &sl->flags);
+ set_bit(W1_SLAVE_DETACH, &sl->flags);
+ mutex_unlock(&sl->master->list_mutex);
+
+ if (destroy_now)
+ destroy_now = !w1_unref_slave(sl);
+ return destroy_now ? 0 : -EBUSY;
}
struct w1_master *w1_search_master_id(u32 id)
@@ -799,7 +850,7 @@ struct w1_slave *w1_search_slave(struct w1_reg_num *id)
mutex_lock(&w1_mlock);
list_for_each_entry(dev, &w1_masters, w1_master_entry) {
- mutex_lock(&dev->mutex);
+ mutex_lock(&dev->list_mutex);
list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
if (sl->reg_num.family == id->family &&
sl->reg_num.id == id->id &&
@@ -810,7 +861,7 @@ struct w1_slave *w1_search_slave(struct w1_reg_num *id)
break;
}
}
- mutex_unlock(&dev->mutex);
+ mutex_unlock(&dev->list_mutex);
if (found)
break;
@@ -830,6 +881,7 @@ void w1_reconnect_slaves(struct w1_family *f, int attach)
dev_dbg(&dev->dev, "Reconnecting slaves in device %s "
"for family %02x.\n", dev->name, f->fid);
mutex_lock(&dev->mutex);
+ mutex_lock(&dev->list_mutex);
list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
/* If it is a new family, slaves with the default
* family driver and are that family will be
@@ -841,14 +893,19 @@ void w1_reconnect_slaves(struct w1_family *f, int attach)
(!attach && sl->family->fid == f->fid)) {
struct w1_reg_num rn;
+ mutex_unlock(&dev->list_mutex);
memcpy(&rn, &sl->reg_num, sizeof(rn));
- w1_slave_detach(sl);
-
- w1_attach_slave_device(dev, &rn);
+ /* If it was already in use let the automatic
+ * scan pick it up again later.
+ */
+ if (!w1_slave_detach(sl))
+ w1_attach_slave_device(dev, &rn);
+ mutex_lock(&dev->list_mutex);
}
}
dev_dbg(&dev->dev, "Reconnecting slaves in device %s "
"has been finished.\n", dev->name);
+ mutex_unlock(&dev->list_mutex);
mutex_unlock(&dev->mutex);
}
mutex_unlock(&w1_mlock);
@@ -876,7 +933,12 @@ void w1_slave_found(struct w1_master *dev, u64 rn)
}
/**
- * Performs a ROM Search & registers any devices found.
+ * w1_search() - Performs a ROM Search & registers any devices found.
+ * @dev: The master device to search
+ * @search_type: W1_SEARCH to search all devices, or W1_ALARM_SEARCH
+ * to return only devices in the alarmed state
+ * @cb: Function to call when a device is found
+ *
* The 1-wire search is a simple binary tree search.
* For each bit of the address, we read two bits and write one bit.
* The bit written will put to sleep all devies that don't match that bit.
@@ -886,8 +948,6 @@ void w1_slave_found(struct w1_master *dev, u64 rn)
*
* See "Application note 187 1-wire search algorithm" at www.maxim-ic.com
*
- * @dev The master device to search
- * @cb Function to call when a device is found
*/
void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb)
{
@@ -898,7 +958,8 @@ void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb
u8 triplet_ret = 0;
search_bit = 0;
- rn = last_rn = 0;
+ rn = dev->search_id;
+ last_rn = 0;
last_device = 0;
last_zero = -1;
@@ -945,7 +1006,7 @@ void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb
else
search_bit = ((last_rn >> i) & 0x1);
- /** Read two bits and write one bit */
+ /* Read two bits and write one bit */
triplet_ret = w1_triplet(dev, search_bit);
/* quit if no device responded */
@@ -960,8 +1021,7 @@ void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb
tmp64 = (triplet_ret >> 2);
rn |= (tmp64 << i);
- /* ensure we're called from kthread and not by netlink callback */
- if (!dev->priv && kthread_should_stop()) {
+ if (test_bit(W1_ABORT_SEARCH, &dev->flags)) {
mutex_unlock(&dev->bus_mutex);
dev_dbg(&dev->dev, "Abort w1_search\n");
return;
@@ -970,11 +1030,30 @@ void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb
mutex_unlock(&dev->bus_mutex);
if ( (triplet_ret & 0x03) != 0x03 ) {
- if ( (desc_bit == last_zero) || (last_zero < 0))
+ if ((desc_bit == last_zero) || (last_zero < 0)) {
last_device = 1;
+ dev->search_id = 0;
+ } else {
+ dev->search_id = rn;
+ }
desc_bit = last_zero;
cb(dev, rn);
}
+
+ if (!last_device && slave_count == dev->max_slave_count &&
+ !test_bit(W1_WARN_MAX_COUNT, &dev->flags)) {
+ /* Only max_slave_count will be scanned in a search,
+ * but it will start where it left off next search
+ * until all ids are identified and then it will start
+ * over. A continued search will report the previous
+ * last id as the first id (provided it is still on the
+ * bus).
+ */
+ dev_info(&dev->dev, "%s: max_slave_count %d reached, "
+ "will continue next search.\n", __func__,
+ dev->max_slave_count);
+ set_bit(W1_WARN_MAX_COUNT, &dev->flags);
+ }
}
}
@@ -983,17 +1062,24 @@ void w1_search_process_cb(struct w1_master *dev, u8 search_type,
{
struct w1_slave *sl, *sln;
+ mutex_lock(&dev->list_mutex);
list_for_each_entry(sl, &dev->slist, w1_slave_entry)
clear_bit(W1_SLAVE_ACTIVE, &sl->flags);
+ mutex_unlock(&dev->list_mutex);
w1_search_devices(dev, search_type, cb);
+ mutex_lock(&dev->list_mutex);
list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
- if (!test_bit(W1_SLAVE_ACTIVE, &sl->flags) && !--sl->ttl)
+ if (!test_bit(W1_SLAVE_ACTIVE, &sl->flags) && !--sl->ttl) {
+ mutex_unlock(&dev->list_mutex);
w1_slave_detach(sl);
+ mutex_lock(&dev->list_mutex);
+ }
else if (test_bit(W1_SLAVE_ACTIVE, &sl->flags))
sl->ttl = dev->slave_ttl;
}
+ mutex_unlock(&dev->list_mutex);
if (dev->search_count > 0)
dev->search_count--;
@@ -1004,6 +1090,32 @@ static void w1_search_process(struct w1_master *dev, u8 search_type)
w1_search_process_cb(dev, search_type, w1_slave_found);
}
+/**
+ * w1_process_callbacks() - execute each dev->async_list callback entry
+ * @dev: w1_master device
+ *
+ * Return: 1 if there were commands to executed 0 otherwise
+ */
+int w1_process_callbacks(struct w1_master *dev)
+{
+ int ret = 0;
+ struct w1_async_cmd *async_cmd, *async_n;
+
+ /* The list can be added to in another thread, loop until it is empty */
+ while (!list_empty(&dev->async_list)) {
+ list_for_each_entry_safe(async_cmd, async_n, &dev->async_list,
+ async_entry) {
+ /* drop the lock, if it is a search it can take a long
+ * time */
+ mutex_unlock(&dev->list_mutex);
+ async_cmd->cb(dev, async_cmd);
+ ret = 1;
+ mutex_lock(&dev->list_mutex);
+ }
+ }
+ return ret;
+}
+
int w1_process(void *data)
{
struct w1_master *dev = (struct w1_master *) data;
@@ -1011,23 +1123,46 @@ int w1_process(void *data)
* time can be calculated in jiffies once.
*/
const unsigned long jtime = msecs_to_jiffies(w1_timeout * 1000);
+ /* remainder if it woke up early */
+ unsigned long jremain = 0;
- while (!kthread_should_stop()) {
- if (dev->search_count) {
+ for (;;) {
+
+ if (!jremain && dev->search_count) {
mutex_lock(&dev->mutex);
w1_search_process(dev, W1_SEARCH);
mutex_unlock(&dev->mutex);
}
+ mutex_lock(&dev->list_mutex);
+ /* Note, w1_process_callback drops the lock while processing,
+ * but locks it again before returning.
+ */
+ if (!w1_process_callbacks(dev) && jremain) {
+ /* a wake up is either to stop the thread, process
+ * callbacks, or search, it isn't process callbacks, so
+ * schedule a search.
+ */
+ jremain = 1;
+ }
+
try_to_freeze();
__set_current_state(TASK_INTERRUPTIBLE);
+ /* hold list_mutex until after interruptible to prevent loosing
+ * the wakeup signal when async_cmd is added.
+ */
+ mutex_unlock(&dev->list_mutex);
+
if (kthread_should_stop())
break;
/* Only sleep when the search is active. */
- if (dev->search_count)
- schedule_timeout(jtime);
+ if (dev->search_count) {
+ if (!jremain)
+ jremain = jtime;
+ jremain = schedule_timeout(jremain);
+ }
else
schedule();
}
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.