diff options
| -rw-r--r-- | drivers/gpio/gpio-aggregator.c | 138 |
1 files changed, 126 insertions, 12 deletions
diff --git a/drivers/gpio/gpio-aggregator.c b/drivers/gpio/gpio-aggregator.c index e8c21ea9a5ea..74e0f9faeaba 100644 --- a/drivers/gpio/gpio-aggregator.c +++ b/drivers/gpio/gpio-aggregator.c @@ -33,6 +33,7 @@ #include "dev-sync-probe.h" #define AGGREGATOR_MAX_GPIOS 512 +#define AGGREGATOR_LEGACY_PREFIX "_sysfs" /* * GPIO Aggregator sysfs interface @@ -131,6 +132,14 @@ static bool gpio_aggregator_is_active(struct gpio_aggregator *aggr) return aggr->probe_data.pdev && platform_get_drvdata(aggr->probe_data.pdev); } +/* Only aggregators created via legacy sysfs can be "activating". */ +static bool gpio_aggregator_is_activating(struct gpio_aggregator *aggr) +{ + lockdep_assert_held(&aggr->lock); + + return aggr->probe_data.pdev && !platform_get_drvdata(aggr->probe_data.pdev); +} + static size_t gpio_aggregator_count_lines(struct gpio_aggregator *aggr) { lockdep_assert_held(&aggr->lock); @@ -189,6 +198,30 @@ static void gpio_aggregator_line_del(struct gpio_aggregator *aggr, list_del(&line->entry); } +static void gpio_aggregator_free_lines(struct gpio_aggregator *aggr) +{ + struct gpio_aggregator_line *line, *tmp; + + list_for_each_entry_safe(line, tmp, &aggr->list_head, entry) { + configfs_unregister_group(&line->group); + /* + * Normally, we acquire aggr->lock within the configfs + * callback. However, in the legacy sysfs interface case, + * calling configfs_(un)register_group while holding + * aggr->lock could cause a deadlock. Fortunately, this is + * unnecessary because the new_device/delete_device path + * and the module unload path are mutually exclusive, + * thanks to an explicit try_module_get. That's why this + * minimal scoped_guard suffices. + */ + scoped_guard(mutex, &aggr->lock) + gpio_aggregator_line_del(aggr, line); + kfree(line->key); + kfree(line->name); + kfree(line); + } +} + /* * GPIO Forwarder @@ -701,7 +734,8 @@ gpio_aggregator_line_key_store(struct config_item *item, const char *page, guard(mutex)(&aggr->lock); - if (gpio_aggregator_is_active(aggr)) + if (gpio_aggregator_is_activating(aggr) || + gpio_aggregator_is_active(aggr)) return -EBUSY; kfree(line->key); @@ -738,7 +772,8 @@ gpio_aggregator_line_name_store(struct config_item *item, const char *page, guard(mutex)(&aggr->lock); - if (gpio_aggregator_is_active(aggr)) + if (gpio_aggregator_is_activating(aggr) || + gpio_aggregator_is_active(aggr)) return -EBUSY; kfree(line->name); @@ -784,7 +819,8 @@ gpio_aggregator_line_offset_store(struct config_item *item, const char *page, guard(mutex)(&aggr->lock); - if (gpio_aggregator_is_active(aggr)) + if (gpio_aggregator_is_activating(aggr) || + gpio_aggregator_is_active(aggr)) return -EBUSY; line->offset = offset; @@ -842,11 +878,12 @@ gpio_aggregator_device_live_store(struct config_item *item, const char *page, if (!try_module_get(THIS_MODULE)) return -ENOENT; - if (live) + if (live && !aggr->init_via_sysfs) gpio_aggregator_lockup_configfs(aggr, true); scoped_guard(mutex, &aggr->lock) { - if (live == gpio_aggregator_is_active(aggr)) + if (gpio_aggregator_is_activating(aggr) || + (live == gpio_aggregator_is_active(aggr))) ret = -EPERM; else if (live) ret = gpio_aggregator_activate(aggr); @@ -858,7 +895,7 @@ gpio_aggregator_device_live_store(struct config_item *item, const char *page, * Undepend is required only if device disablement (live == 0) * succeeds or if device enablement (live == 1) fails. */ - if (live == !!ret) + if (live == !!ret && !aggr->init_via_sysfs) gpio_aggregator_lockup_configfs(aggr, false); module_put(THIS_MODULE); @@ -902,7 +939,7 @@ static void gpio_aggregator_device_release(struct config_item *item) struct gpio_aggregator *aggr = to_gpio_aggregator(item); /* - * If the aggregator is active, this code wouldn't be reached, + * At this point, aggr is neither active nor activating, * so calling gpio_aggregator_deactivate() is always unnecessary. */ gpio_aggregator_free(aggr); @@ -924,6 +961,15 @@ gpio_aggregator_device_make_group(struct config_group *group, const char *name) if (ret != 1 || nchar != strlen(name)) return ERR_PTR(-EINVAL); + if (aggr->init_via_sysfs) + /* + * Aggregators created via legacy sysfs interface are exposed as + * default groups, which means rmdir(2) is prohibited for them. + * For simplicity, and to avoid confusion, we also prohibit + * mkdir(2). + */ + return ERR_PTR(-EPERM); + guard(mutex)(&aggr->lock); if (gpio_aggregator_is_active(aggr)) @@ -961,6 +1007,14 @@ gpio_aggregator_make_group(struct config_group *group, const char *name) struct gpio_aggregator *aggr; int ret; + /* + * "_sysfs" prefix is reserved for auto-generated config group + * for devices create via legacy sysfs interface. + */ + if (strncmp(name, AGGREGATOR_LEGACY_PREFIX, + sizeof(AGGREGATOR_LEGACY_PREFIX)) == 0) + return ERR_PTR(-EINVAL); + /* arg space is unneeded */ ret = gpio_aggregator_alloc(&aggr, 0); if (ret) @@ -996,6 +1050,8 @@ static struct configfs_subsystem gpio_aggregator_subsys = { static int gpio_aggregator_parse(struct gpio_aggregator *aggr) { char *args = skip_spaces(aggr->args); + struct gpio_aggregator_line *line; + char name[CONFIGFS_ITEM_NAME_LEN]; char *key, *offsets, *p; unsigned int i, n = 0; int error = 0; @@ -1012,9 +1068,24 @@ static int gpio_aggregator_parse(struct gpio_aggregator *aggr) p = get_options(offsets, 0, &error); if (error == 0 || *p) { /* Named GPIO line */ + scnprintf(name, sizeof(name), "line%u", n); + line = gpio_aggregator_line_alloc(aggr, n, key, -1); + if (!line) { + error = -ENOMEM; + goto err; + } + config_group_init_type_name(&line->group, name, + &gpio_aggregator_line_type); + error = configfs_register_group(&aggr->group, + &line->group); + if (error) + goto err; + scoped_guard(mutex, &aggr->lock) + gpio_aggregator_line_add(aggr, line); + error = gpio_aggregator_add_gpio(aggr, key, U16_MAX, &n); if (error) - return error; + goto err; key = offsets; continue; @@ -1028,9 +1099,24 @@ static int gpio_aggregator_parse(struct gpio_aggregator *aggr) } for_each_set_bit(i, bitmap, AGGREGATOR_MAX_GPIOS) { + scnprintf(name, sizeof(name), "line%u", n); + line = gpio_aggregator_line_alloc(aggr, n, key, i); + if (!line) { + error = -ENOMEM; + goto err; + } + config_group_init_type_name(&line->group, name, + &gpio_aggregator_line_type); + error = configfs_register_group(&aggr->group, + &line->group); + if (error) + goto err; + scoped_guard(mutex, &aggr->lock) + gpio_aggregator_line_add(aggr, line); + error = gpio_aggregator_add_gpio(aggr, key, i, &n); if (error) - return error; + goto err; } args = next_arg(args, &key, &p); @@ -1038,15 +1124,20 @@ static int gpio_aggregator_parse(struct gpio_aggregator *aggr) if (!n) { pr_err("No GPIOs specified\n"); - return -EINVAL; + goto err; } return 0; + +err: + gpio_aggregator_free_lines(aggr); + return error; } static ssize_t gpio_aggregator_new_device_store(struct device_driver *driver, const char *buf, size_t count) { + char name[CONFIGFS_ITEM_NAME_LEN]; struct gpio_aggregator *aggr; struct platform_device *pdev; int res; @@ -1075,10 +1166,25 @@ static ssize_t gpio_aggregator_new_device_store(struct device_driver *driver, goto free_table; } - res = gpio_aggregator_parse(aggr); + scnprintf(name, sizeof(name), "%s.%d", AGGREGATOR_LEGACY_PREFIX, aggr->id); + config_group_init_type_name(&aggr->group, name, &gpio_aggregator_device_type); + + /* + * Since the device created by sysfs might be toggled via configfs + * 'live' attribute later, this initialization is needed. + */ + dev_sync_probe_init(&aggr->probe_data); + + /* Expose to configfs */ + res = configfs_register_group(&gpio_aggregator_subsys.su_group, + &aggr->group); if (res) goto free_dev_id; + res = gpio_aggregator_parse(aggr); + if (res) + goto unregister_group; + gpiod_add_lookup_table(aggr->lookups); pdev = platform_device_register_simple(DRV_NAME, aggr->id, NULL, 0); @@ -1093,6 +1199,8 @@ static ssize_t gpio_aggregator_new_device_store(struct device_driver *driver, remove_table: gpiod_remove_lookup_table(aggr->lookups); +unregister_group: + configfs_unregister_group(&aggr->group); free_dev_id: kfree(aggr->lookups->dev_id); free_table: @@ -1109,7 +1217,13 @@ static struct driver_attribute driver_attr_gpio_aggregator_new_device = static void gpio_aggregator_destroy(struct gpio_aggregator *aggr) { - gpio_aggregator_deactivate(aggr); + scoped_guard(mutex, &aggr->lock) { + if (gpio_aggregator_is_activating(aggr) || + gpio_aggregator_is_active(aggr)) + gpio_aggregator_deactivate(aggr); + } + gpio_aggregator_free_lines(aggr); + configfs_unregister_group(&aggr->group); kfree(aggr); } |