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authorPatrice Chotard <patrice.chotard@st.com>2013-04-11 11:01:27 +0200
committerLinus Walleij <linus.walleij@linaro.org>2013-04-26 17:01:35 +0200
commit42fed7ba44e4e8c1fb27b28ad14490cb1daff3c7 (patch)
tree3caafd69ed9807e9a15f14d6c482fa1f1a697a8b /drivers/pinctrl/pinconf.c
parentcb6d315dc36ce56bc017051befa9ac9391300eb9 (diff)
downloadlinux-42fed7ba44e4e8c1fb27b28ad14490cb1daff3c7.tar.bz2
pinctrl: move subsystem mutex to pinctrl_dev struct
This mutex avoids deadlock in case of use of multiple pin controllers. Before this modification, by using a global mutex, deadlock appeared when, for example, a call to pinctrl_pins_show() locked the pinctrl_mutex, called the ops->pin_dbg_show of a particular pin controller. If this pin controller needs I2C access to retrieve configuration information and I2C driver is using pinctrl to drive its pins, a call to pinctrl_select_state() try to lock again pinctrl_mutex which leads to a deadlock. Notice that the mutex grab from the two direction functions was moved into pinctrl_gpio_direction(). For several cases, we can't replace pinctrl_mutex by pctldev->mutex, because at this stage, pctldev is not accessible : - pinctrl_get()/pinctrl_put() - pinctrl_register_maps() So add respectively pinctrl_list_mutex and pinctrl_maps_mutex in order to protect pinctrl_list and pinctrl_maps list instead. Reintroduce pinctrldev_list_mutex in find_pinctrl_by_of_node(), pinctrl_find_and_add_gpio_range() pinctrl_request_gpio(), pinctrl_free_gpio(), pinctrl_gpio_direction(), pinctrl_devices_show(), pinctrl_register() and pinctrl_unregister() to protect pinctrldev_list. Changes v2->v3: - Fix a missing EXPORT_SYMBOL_GPL() for pinctrl_select_state(). Changes v1->v2: - pinctrl_select_state_locked() is removed, all lock mechanism is located inside pinctrl_select_state(). When parsing the state->setting list, take the per-pin-controller driver lock. (Patrice). - Introduce pinctrldev_list_mutex to protect pinctrldev_list in all functions which parse or modify pictrldev_list. (Patrice). - move find_pinctrl_by_of_node() from pinctrl/devicetree.c to pinctrl/core.c in order to protect pinctrldev_list. (Patrice). - Sink mutex:es into some functions and remove some _locked variants down to where the lists are actually accessed to make things simpler. (Linus) - Drop *all* mutexes completely from pinctrl_lookup_state() and pinctrl_select_state() - no relevant mutex was taken and it was unclear what this was protecting against. (Linus) Reported by : Seraphin Bonnaffe <seraphin.bonnaffe@stericsson.com> Signed-off-by: Patrice Chotard <patrice.chotard@st.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Diffstat (limited to 'drivers/pinctrl/pinconf.c')
-rw-r--r--drivers/pinctrl/pinconf.c46
1 files changed, 24 insertions, 22 deletions
diff --git a/drivers/pinctrl/pinconf.c b/drivers/pinctrl/pinconf.c
index 32f96808202a..c67c37e23dd7 100644
--- a/drivers/pinctrl/pinconf.c
+++ b/drivers/pinctrl/pinconf.c
@@ -89,14 +89,14 @@ int pin_config_get(const char *dev_name, const char *name,
struct pinctrl_dev *pctldev;
int pin;
- mutex_lock(&pinctrl_mutex);
-
pctldev = get_pinctrl_dev_from_devname(dev_name);
if (!pctldev) {
pin = -EINVAL;
- goto unlock;
+ return pin;
}
+ mutex_lock(&pctldev->mutex);
+
pin = pin_get_from_name(pctldev, name);
if (pin < 0)
goto unlock;
@@ -104,7 +104,7 @@ int pin_config_get(const char *dev_name, const char *name,
pin = pin_config_get_for_pin(pctldev, pin, config);
unlock:
- mutex_unlock(&pinctrl_mutex);
+ mutex_unlock(&pctldev->mutex);
return pin;
}
EXPORT_SYMBOL(pin_config_get);
@@ -145,14 +145,14 @@ int pin_config_set(const char *dev_name, const char *name,
struct pinctrl_dev *pctldev;
int pin, ret;
- mutex_lock(&pinctrl_mutex);
-
pctldev = get_pinctrl_dev_from_devname(dev_name);
if (!pctldev) {
ret = -EINVAL;
- goto unlock;
+ return ret;
}
+ mutex_lock(&pctldev->mutex);
+
pin = pin_get_from_name(pctldev, name);
if (pin < 0) {
ret = pin;
@@ -162,7 +162,7 @@ int pin_config_set(const char *dev_name, const char *name,
ret = pin_config_set_for_pin(pctldev, pin, config);
unlock:
- mutex_unlock(&pinctrl_mutex);
+ mutex_unlock(&pctldev->mutex);
return ret;
}
EXPORT_SYMBOL(pin_config_set);
@@ -174,13 +174,14 @@ int pin_config_group_get(const char *dev_name, const char *pin_group,
const struct pinconf_ops *ops;
int selector, ret;
- mutex_lock(&pinctrl_mutex);
-
pctldev = get_pinctrl_dev_from_devname(dev_name);
if (!pctldev) {
ret = -EINVAL;
- goto unlock;
+ return ret;
}
+
+ mutex_lock(&pctldev->mutex);
+
ops = pctldev->desc->confops;
if (!ops || !ops->pin_config_group_get) {
@@ -200,7 +201,7 @@ int pin_config_group_get(const char *dev_name, const char *pin_group,
ret = ops->pin_config_group_get(pctldev, selector, config);
unlock:
- mutex_unlock(&pinctrl_mutex);
+ mutex_unlock(&pctldev->mutex);
return ret;
}
EXPORT_SYMBOL(pin_config_group_get);
@@ -217,13 +218,14 @@ int pin_config_group_set(const char *dev_name, const char *pin_group,
int ret;
int i;
- mutex_lock(&pinctrl_mutex);
-
pctldev = get_pinctrl_dev_from_devname(dev_name);
if (!pctldev) {
ret = -EINVAL;
- goto unlock;
+ return ret;
}
+
+ mutex_lock(&pctldev->mutex);
+
ops = pctldev->desc->confops;
pctlops = pctldev->desc->pctlops;
@@ -279,7 +281,7 @@ int pin_config_group_set(const char *dev_name, const char *pin_group,
ret = 0;
unlock:
- mutex_unlock(&pinctrl_mutex);
+ mutex_unlock(&pctldev->mutex);
return ret;
}
@@ -487,7 +489,7 @@ static int pinconf_pins_show(struct seq_file *s, void *what)
seq_puts(s, "Pin config settings per pin\n");
seq_puts(s, "Format: pin (name): configs\n");
- mutex_lock(&pinctrl_mutex);
+ mutex_lock(&pctldev->mutex);
/* The pin number can be retrived from the pin controller descriptor */
for (i = 0; i < pctldev->desc->npins; i++) {
@@ -507,7 +509,7 @@ static int pinconf_pins_show(struct seq_file *s, void *what)
seq_printf(s, "\n");
}
- mutex_unlock(&pinctrl_mutex);
+ mutex_unlock(&pctldev->mutex);
return 0;
}
@@ -608,7 +610,7 @@ static int pinconf_dbg_config_print(struct seq_file *s, void *d)
bool found = false;
unsigned long config;
- mutex_lock(&pinctrl_mutex);
+ mutex_lock(&pctldev->mutex);
/* Parse the pinctrl map and look for the elected pin/state */
for_each_maps(maps_node, i, map) {
@@ -657,7 +659,7 @@ static int pinconf_dbg_config_print(struct seq_file *s, void *d)
confops->pin_config_config_dbg_show(pctldev, s, config);
exit:
- mutex_unlock(&pinctrl_mutex);
+ mutex_unlock(&pctldev->mutex);
return 0;
}
@@ -747,7 +749,7 @@ static int pinconf_dbg_config_write(struct file *file,
return -EINVAL;
strncpy(config, token, MAX_NAME_LEN);
- mutex_lock(&pinctrl_mutex);
+ mutex_lock(&pinctrl_maps_mutex);
/* Parse the pinctrl map and look for the selected dev/state/pin */
for_each_maps(maps_node, i, map) {
@@ -785,7 +787,7 @@ static int pinconf_dbg_config_write(struct file *file,
}
exit:
- mutex_unlock(&pinctrl_mutex);
+ mutex_unlock(&pinctrl_maps_mutex);
return count;
}