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![Doug Anderson](/assets/img/avatar_default.png)
Way back, when the world was a simpler place and there was no war, no evil, and no kernel bugs, there was just a single pinctrl lock. That was how the world was when (57291ce
pinctrl: core device tree mapping table parsing support) was written. In that case, there were instances where the pinctrl mutex was already held when pinctrl_register_map() was called, hence a "locked" parameter was passed to the function to indicate that the mutex was already locked (so we shouldn't lock it again). A few years ago in (42fed7b
pinctrl: move subsystem mutex to pinctrl_dev struct), we switched to a separate pinctrl_maps_mutex. ...but (oops) we forgot to re-think about the whole "locked" parameter for pinctrl_register_map(). Basically the "locked" parameter appears to still refer to whether the bigger pinctrl_dev mutex is locked, but we're using it to skip locks of our (now separate) pinctrl_maps_mutex. That's kind of a bad thing(TM). Probably nobody noticed because most of the calls to pinctrl_register_map happen at boot time and we've got synchronous device probing. ...and even cases where we're asynchronous don't end up actually hitting the race too often. ...but after banging my head against the wall for a bug that reproduced 1 out of 1000 reboots and lots of looking through kgdb, I finally noticed this. Anyway, we can now safely remove the "locked" parameter and go back to a war-free, evil-free, and kernel-bug-free world. Fixes:42fed7ba44
("pinctrl: move subsystem mutex to pinctrl_dev struct") Signed-off-by: Doug Anderson <dianders@chromium.org> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
199 lines
6.4 KiB
C
199 lines
6.4 KiB
C
/*
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* Core private header for the pin control subsystem
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*
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* Copyright (C) 2011 ST-Ericsson SA
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* Written on behalf of Linaro for ST-Ericsson
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*
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* Author: Linus Walleij <linus.walleij@linaro.org>
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*
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* License terms: GNU General Public License (GPL) version 2
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*/
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#include <linux/kref.h>
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#include <linux/mutex.h>
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#include <linux/radix-tree.h>
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#include <linux/pinctrl/pinconf.h>
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#include <linux/pinctrl/machine.h>
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struct pinctrl_gpio_range;
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/**
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* struct pinctrl_dev - pin control class device
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* @node: node to include this pin controller in the global pin controller list
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* @desc: the pin controller descriptor supplied when initializing this pin
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* controller
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* @pin_desc_tree: each pin descriptor for this pin controller is stored in
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* this radix tree
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* @gpio_ranges: a list of GPIO ranges that is handled by this pin controller,
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* ranges are added to this list at runtime
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* @dev: the device entry for this pin controller
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* @owner: module providing the pin controller, used for refcounting
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* @driver_data: driver data for drivers registering to the pin controller
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* subsystem
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* @p: result of pinctrl_get() for this device
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* @hog_default: default state for pins hogged by this device
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* @hog_sleep: sleep state for pins hogged by this device
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* @mutex: mutex taken on each pin controller specific action
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* @device_root: debugfs root for this device
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*/
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struct pinctrl_dev {
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struct list_head node;
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struct pinctrl_desc *desc;
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struct radix_tree_root pin_desc_tree;
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struct list_head gpio_ranges;
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struct device *dev;
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struct module *owner;
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void *driver_data;
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struct pinctrl *p;
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struct pinctrl_state *hog_default;
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struct pinctrl_state *hog_sleep;
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struct mutex mutex;
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#ifdef CONFIG_DEBUG_FS
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struct dentry *device_root;
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#endif
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};
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/**
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* struct pinctrl - per-device pin control state holder
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* @node: global list node
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* @dev: the device using this pin control handle
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* @states: a list of states for this device
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* @state: the current state
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* @dt_maps: the mapping table chunks dynamically parsed from device tree for
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* this device, if any
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* @users: reference count
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*/
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struct pinctrl {
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struct list_head node;
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struct device *dev;
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struct list_head states;
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struct pinctrl_state *state;
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struct list_head dt_maps;
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struct kref users;
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};
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/**
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* struct pinctrl_state - a pinctrl state for a device
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* @node: list node for struct pinctrl's @states field
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* @name: the name of this state
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* @settings: a list of settings for this state
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*/
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struct pinctrl_state {
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struct list_head node;
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const char *name;
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struct list_head settings;
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};
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/**
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* struct pinctrl_setting_mux - setting data for MAP_TYPE_MUX_GROUP
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* @group: the group selector to program
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* @func: the function selector to program
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*/
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struct pinctrl_setting_mux {
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unsigned group;
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unsigned func;
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};
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/**
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* struct pinctrl_setting_configs - setting data for MAP_TYPE_CONFIGS_*
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* @group_or_pin: the group selector or pin ID to program
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* @configs: a pointer to an array of config parameters/values to program into
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* hardware. Each individual pin controller defines the format and meaning
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* of config parameters.
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* @num_configs: the number of entries in array @configs
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*/
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struct pinctrl_setting_configs {
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unsigned group_or_pin;
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unsigned long *configs;
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unsigned num_configs;
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};
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/**
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* struct pinctrl_setting - an individual mux or config setting
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* @node: list node for struct pinctrl_settings's @settings field
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* @type: the type of setting
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* @pctldev: pin control device handling to be programmed. Not used for
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* PIN_MAP_TYPE_DUMMY_STATE.
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* @dev_name: the name of the device using this state
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* @data: Data specific to the setting type
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*/
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struct pinctrl_setting {
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struct list_head node;
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enum pinctrl_map_type type;
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struct pinctrl_dev *pctldev;
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const char *dev_name;
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union {
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struct pinctrl_setting_mux mux;
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struct pinctrl_setting_configs configs;
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} data;
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};
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/**
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* struct pin_desc - pin descriptor for each physical pin in the arch
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* @pctldev: corresponding pin control device
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* @name: a name for the pin, e.g. the name of the pin/pad/finger on a
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* datasheet or such
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* @dynamic_name: if the name of this pin was dynamically allocated
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* @mux_usecount: If zero, the pin is not claimed, and @owner should be NULL.
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* If non-zero, this pin is claimed by @owner. This field is an integer
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* rather than a boolean, since pinctrl_get() might process multiple
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* mapping table entries that refer to, and hence claim, the same group
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* or pin, and each of these will increment the @usecount.
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* @mux_owner: The name of device that called pinctrl_get().
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* @mux_setting: The most recent selected mux setting for this pin, if any.
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* @gpio_owner: If pinctrl_request_gpio() was called for this pin, this is
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* the name of the GPIO that "owns" this pin.
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*/
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struct pin_desc {
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struct pinctrl_dev *pctldev;
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const char *name;
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bool dynamic_name;
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/* These fields only added when supporting pinmux drivers */
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#ifdef CONFIG_PINMUX
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unsigned mux_usecount;
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const char *mux_owner;
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const struct pinctrl_setting_mux *mux_setting;
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const char *gpio_owner;
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#endif
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};
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/**
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* struct pinctrl_maps - a list item containing part of the mapping table
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* @node: mapping table list node
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* @maps: array of mapping table entries
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* @num_maps: the number of entries in @maps
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*/
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struct pinctrl_maps {
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struct list_head node;
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struct pinctrl_map const *maps;
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unsigned num_maps;
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};
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struct pinctrl_dev *get_pinctrl_dev_from_devname(const char *dev_name);
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struct pinctrl_dev *get_pinctrl_dev_from_of_node(struct device_node *np);
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int pin_get_from_name(struct pinctrl_dev *pctldev, const char *name);
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const char *pin_get_name(struct pinctrl_dev *pctldev, const unsigned pin);
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int pinctrl_get_group_selector(struct pinctrl_dev *pctldev,
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const char *pin_group);
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static inline struct pin_desc *pin_desc_get(struct pinctrl_dev *pctldev,
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unsigned int pin)
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{
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return radix_tree_lookup(&pctldev->pin_desc_tree, pin);
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}
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int pinctrl_register_map(struct pinctrl_map const *maps, unsigned num_maps,
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bool dup);
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void pinctrl_unregister_map(struct pinctrl_map const *map);
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extern int pinctrl_force_sleep(struct pinctrl_dev *pctldev);
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extern int pinctrl_force_default(struct pinctrl_dev *pctldev);
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extern struct mutex pinctrl_maps_mutex;
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extern struct list_head pinctrl_maps;
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#define for_each_maps(_maps_node_, _i_, _map_) \
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list_for_each_entry(_maps_node_, &pinctrl_maps, node) \
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for (_i_ = 0, _map_ = &_maps_node_->maps[_i_]; \
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_i_ < _maps_node_->num_maps; \
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_i_++, _map_ = &_maps_node_->maps[_i_])
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