diff options
Diffstat (limited to 'drivers/gpio/gpiolib-cdev.c')
| -rw-r--r-- | drivers/gpio/gpiolib-cdev.c | 505 |
1 files changed, 244 insertions, 261 deletions
diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index d09c7d728365..e6a289fa0f8f 100644 --- a/drivers/gpio/gpiolib-cdev.c +++ b/drivers/gpio/gpiolib-cdev.c @@ -16,16 +16,15 @@ #include <linux/hte.h> #include <linux/interrupt.h> #include <linux/irqreturn.h> -#include <linux/kernel.h> #include <linux/kfifo.h> #include <linux/module.h> #include <linux/mutex.h> #include <linux/overflow.h> #include <linux/pinctrl/consumer.h> #include <linux/poll.h> -#include <linux/rbtree.h> #include <linux/seq_file.h> #include <linux/spinlock.h> +#include <linux/string.h> #include <linux/timekeeping.h> #include <linux/uaccess.h> #include <linux/workqueue.h> @@ -89,6 +88,10 @@ struct linehandle_state { GPIOHANDLE_REQUEST_OPEN_DRAIN | \ GPIOHANDLE_REQUEST_OPEN_SOURCE) +#define GPIOHANDLE_REQUEST_DIRECTION_FLAGS \ + (GPIOHANDLE_REQUEST_INPUT | \ + GPIOHANDLE_REQUEST_OUTPUT) + static int linehandle_validate_flags(u32 flags) { /* Return an error if an unknown flag is set */ @@ -139,18 +142,22 @@ static int linehandle_validate_flags(u32 flags) static void linehandle_flags_to_desc_flags(u32 lflags, unsigned long *flagsp) { - assign_bit(FLAG_ACTIVE_LOW, flagsp, + unsigned long flags = READ_ONCE(*flagsp); + + assign_bit(FLAG_ACTIVE_LOW, &flags, lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW); - assign_bit(FLAG_OPEN_DRAIN, flagsp, + assign_bit(FLAG_OPEN_DRAIN, &flags, lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN); - assign_bit(FLAG_OPEN_SOURCE, flagsp, + assign_bit(FLAG_OPEN_SOURCE, &flags, lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE); - assign_bit(FLAG_PULL_UP, flagsp, + assign_bit(FLAG_PULL_UP, &flags, lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP); - assign_bit(FLAG_PULL_DOWN, flagsp, + assign_bit(FLAG_PULL_DOWN, &flags, lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN); - assign_bit(FLAG_BIAS_DISABLE, flagsp, + assign_bit(FLAG_BIAS_DISABLE, &flags, lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE); + + WRITE_ONCE(*flagsp, flags); } static long linehandle_set_config(struct linehandle_state *lh, @@ -169,22 +176,22 @@ static long linehandle_set_config(struct linehandle_state *lh, if (ret) return ret; + /* Lines must be reconfigured explicitly as input or output. */ + if (!(lflags & GPIOHANDLE_REQUEST_DIRECTION_FLAGS)) + return -EINVAL; + for (i = 0; i < lh->num_descs; i++) { desc = lh->descs[i]; - linehandle_flags_to_desc_flags(gcnf.flags, &desc->flags); + linehandle_flags_to_desc_flags(lflags, &desc->flags); - /* - * Lines have to be requested explicitly for input - * or output, else the line will be treated "as is". - */ if (lflags & GPIOHANDLE_REQUEST_OUTPUT) { int val = !!gcnf.default_values[i]; - ret = gpiod_direction_output(desc, val); + ret = gpiod_direction_output_nonotify(desc, val); if (ret) return ret; - } else if (lflags & GPIOHANDLE_REQUEST_INPUT) { - ret = gpiod_direction_input(desc); + } else { + ret = gpiod_direction_input_nonotify(desc); if (ret) return ret; } @@ -355,11 +362,11 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip) if (lflags & GPIOHANDLE_REQUEST_OUTPUT) { int val = !!handlereq.default_values[i]; - ret = gpiod_direction_output(desc, val); + ret = gpiod_direction_output_nonotify(desc, val); if (ret) goto out_free_lh; } else if (lflags & GPIOHANDLE_REQUEST_INPUT) { - ret = gpiod_direction_input(desc); + ret = gpiod_direction_input_nonotify(desc); if (ret) goto out_free_lh; } @@ -413,7 +420,6 @@ out_free_lh: /** * struct line - contains the state of a requested line - * @node: to store the object in supinfo_tree if supplemental * @desc: the GPIO descriptor for this line. * @req: the corresponding line request * @irq: the interrupt triggered in response to events on this GPIO @@ -426,7 +432,6 @@ out_free_lh: * @line_seqno: the seqno for the current edge event in the sequence of * events for this line. * @work: the worker that implements software debouncing - * @debounce_period_us: the debounce period in microseconds * @sw_debounced: flag indicating if the software debouncer is active * @level: the current debounced physical level of the line * @hdesc: the Hardware Timestamp Engine (HTE) descriptor @@ -435,7 +440,6 @@ out_free_lh: * @last_seqno: the last sequence number before debounce period expires */ struct line { - struct rb_node node; struct gpio_desc *desc; /* * -- edge detector specific fields -- @@ -446,7 +450,7 @@ struct line { * The flags for the active edge detector configuration. * * edflags is set by linereq_create(), linereq_free(), and - * linereq_set_config_unlocked(), which are themselves mutually + * linereq_set_config(), which are themselves mutually * exclusive, and is accessed by edge_irq_thread(), * process_hw_ts_thread() and debounce_work_func(), * which can all live with a slightly stale value. @@ -470,15 +474,6 @@ struct line { */ struct delayed_work work; /* - * debounce_period_us is accessed by debounce_irq_handler() and - * process_hw_ts() which are disabled when modified by - * debounce_setup(), edge_detector_setup() or edge_detector_stop() - * or can live with a stale version when updated by - * edge_detector_update(). - * The modifying functions are themselves mutually exclusive. - */ - unsigned int debounce_period_us; - /* * sw_debounce is accessed by linereq_set_config(), which is the * only setter, and linereq_get_values(), which can live with a * slightly stale value. @@ -510,17 +505,6 @@ struct line { #endif /* CONFIG_HTE */ }; -/* - * a rbtree of the struct lines containing supplemental info. - * Used to populate gpio_v2_line_info with cdev specific fields not contained - * in the struct gpio_desc. - * A line is determined to contain supplemental information by - * line_has_supinfo(). - */ -static struct rb_root supinfo_tree = RB_ROOT; -/* covers supinfo_tree */ -static DEFINE_SPINLOCK(supinfo_lock); - /** * struct linereq - contains the state of a userspace line request * @gdev: the GPIO device the line request pertains to @@ -534,8 +518,7 @@ static DEFINE_SPINLOCK(supinfo_lock); * this line request. Note that this is not used when @num_lines is 1, as * the line_seqno is then the same and is cheaper to calculate. * @config_mutex: mutex for serializing ioctl() calls to ensure consistency - * of configuration, particularly multi-step accesses to desc flags and - * changes to supinfo status. + * of configuration, particularly multi-step accesses to desc flags. * @lines: the lines held by this line request, with @num_lines elements. */ struct linereq { @@ -551,103 +534,6 @@ struct linereq { struct line lines[] __counted_by(num_lines); }; -static void supinfo_insert(struct line *line) -{ - struct rb_node **new = &(supinfo_tree.rb_node), *parent = NULL; - struct line *entry; - - guard(spinlock)(&supinfo_lock); - - while (*new) { - entry = container_of(*new, struct line, node); - - parent = *new; - if (line->desc < entry->desc) { - new = &((*new)->rb_left); - } else if (line->desc > entry->desc) { - new = &((*new)->rb_right); - } else { - /* this should never happen */ - WARN(1, "duplicate line inserted"); - return; - } - } - - rb_link_node(&line->node, parent, new); - rb_insert_color(&line->node, &supinfo_tree); -} - -static void supinfo_erase(struct line *line) -{ - guard(spinlock)(&supinfo_lock); - - rb_erase(&line->node, &supinfo_tree); -} - -static struct line *supinfo_find(struct gpio_desc *desc) -{ - struct rb_node *node = supinfo_tree.rb_node; - struct line *line; - - while (node) { - line = container_of(node, struct line, node); - if (desc < line->desc) - node = node->rb_left; - else if (desc > line->desc) - node = node->rb_right; - else - return line; - } - return NULL; -} - -static void supinfo_to_lineinfo(struct gpio_desc *desc, - struct gpio_v2_line_info *info) -{ - struct gpio_v2_line_attribute *attr; - struct line *line; - - guard(spinlock)(&supinfo_lock); - - line = supinfo_find(desc); - if (!line) - return; - - attr = &info->attrs[info->num_attrs]; - attr->id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE; - attr->debounce_period_us = READ_ONCE(line->debounce_period_us); - info->num_attrs++; -} - -static inline bool line_has_supinfo(struct line *line) -{ - return READ_ONCE(line->debounce_period_us); -} - -/* - * Checks line_has_supinfo() before and after the change to avoid unnecessary - * supinfo_tree access. - * Called indirectly by linereq_create() or linereq_set_config() so line - * is already protected from concurrent changes. - */ -static void line_set_debounce_period(struct line *line, - unsigned int debounce_period_us) -{ - bool was_suppl = line_has_supinfo(line); - - WRITE_ONCE(line->debounce_period_us, debounce_period_us); - - /* if supinfo status is unchanged then we're done */ - if (line_has_supinfo(line) == was_suppl) - return; - - /* supinfo status has changed, so update the tree */ - if (was_suppl) - supinfo_erase(line); - else - supinfo_insert(line); -} - #define GPIO_V2_LINE_BIAS_FLAGS \ (GPIO_V2_LINE_FLAG_BIAS_PULL_UP | \ GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | \ @@ -815,7 +701,7 @@ static enum hte_return process_hw_ts(struct hte_ts_data *ts, void *p) line->total_discard_seq++; line->last_seqno = ts->seq; mod_delayed_work(system_wq, &line->work, - usecs_to_jiffies(READ_ONCE(line->debounce_period_us))); + usecs_to_jiffies(READ_ONCE(line->desc->debounce_period_us))); } else { if (unlikely(ts->seq < line->line_seqno)) return HTE_CB_HANDLED; @@ -956,7 +842,7 @@ static irqreturn_t debounce_irq_handler(int irq, void *p) struct line *line = p; mod_delayed_work(system_wq, &line->work, - usecs_to_jiffies(READ_ONCE(line->debounce_period_us))); + usecs_to_jiffies(READ_ONCE(line->desc->debounce_period_us))); return IRQ_HANDLED; } @@ -1036,12 +922,13 @@ static int debounce_setup(struct line *line, unsigned int debounce_period_us) int ret, level, irq; char *label; - /* try hardware */ - ret = gpiod_set_debounce(line->desc, debounce_period_us); - if (!ret) { - line_set_debounce_period(line, debounce_period_us); - return ret; - } + /* + * Try hardware. Skip gpiod_set_config() to avoid emitting two + * CHANGED_CONFIG line state events. + */ + ret = gpio_do_set_config(line->desc, + pinconf_to_config_packed(PIN_CONFIG_INPUT_DEBOUNCE, + debounce_period_us)); if (ret != -ENOTSUPP) return ret; @@ -1124,10 +1011,19 @@ static void edge_detector_stop(struct line *line) cancel_delayed_work_sync(&line->work); WRITE_ONCE(line->sw_debounced, 0); WRITE_ONCE(line->edflags, 0); - line_set_debounce_period(line, 0); + if (line->desc) + WRITE_ONCE(line->desc->debounce_period_us, 0); /* do not change line->level - see comment in debounced_value() */ } +static int edge_detector_fifo_init(struct linereq *req) +{ + if (kfifo_initialized(&req->events)) + return 0; + + return kfifo_alloc(&req->events, req->event_buffer_size, GFP_KERNEL); +} + static int edge_detector_setup(struct line *line, struct gpio_v2_line_config *lc, unsigned int line_idx, u64 edflags) @@ -1139,9 +1035,8 @@ static int edge_detector_setup(struct line *line, char *label; eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS; - if (eflags && !kfifo_initialized(&line->req->events)) { - ret = kfifo_alloc(&line->req->events, - line->req->event_buffer_size, GFP_KERNEL); + if (eflags) { + ret = edge_detector_fifo_init(line->req); if (ret) return ret; } @@ -1150,7 +1045,7 @@ static int edge_detector_setup(struct line *line, ret = debounce_setup(line, debounce_period_us); if (ret) return ret; - line_set_debounce_period(line, debounce_period_us); + WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us); } /* detection disabled or sw debouncer will provide edge detection */ @@ -1198,12 +1093,19 @@ static int edge_detector_update(struct line *line, gpio_v2_line_config_debounce_period(lc, line_idx); if ((active_edflags == edflags) && - (READ_ONCE(line->debounce_period_us) == debounce_period_us)) + (READ_ONCE(line->desc->debounce_period_us) == debounce_period_us)) return 0; /* sw debounced and still will be...*/ if (debounce_period_us && READ_ONCE(line->sw_debounced)) { - line_set_debounce_period(line, debounce_period_us); + WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us); + /* + * ensure event fifo is initialised if edge detection + * is now enabled. + */ + if (edflags & GPIO_V2_LINE_EDGE_FLAGS) + return edge_detector_fifo_init(line->req); + return 0; } @@ -1313,7 +1215,7 @@ static int gpio_v2_line_config_validate(struct gpio_v2_line_config *lc, if (lc->num_attrs > GPIO_V2_LINE_NUM_ATTRS_MAX) return -EINVAL; - if (memchr_inv(lc->padding, 0, sizeof(lc->padding))) + if (!mem_is_zero(lc->padding, sizeof(lc->padding))) return -EINVAL; for (i = 0; i < num_lines; i++) { @@ -1330,38 +1232,42 @@ static int gpio_v2_line_config_validate(struct gpio_v2_line_config *lc, return 0; } -static void gpio_v2_line_config_flags_to_desc_flags(u64 flags, +static void gpio_v2_line_config_flags_to_desc_flags(u64 lflags, unsigned long *flagsp) { - assign_bit(FLAG_ACTIVE_LOW, flagsp, - flags & GPIO_V2_LINE_FLAG_ACTIVE_LOW); + unsigned long flags = READ_ONCE(*flagsp); + + assign_bit(FLAG_ACTIVE_LOW, &flags, + lflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW); - if (flags & GPIO_V2_LINE_FLAG_OUTPUT) - set_bit(FLAG_IS_OUT, flagsp); - else if (flags & GPIO_V2_LINE_FLAG_INPUT) - clear_bit(FLAG_IS_OUT, flagsp); + if (lflags & GPIO_V2_LINE_FLAG_OUTPUT) + set_bit(FLAG_IS_OUT, &flags); + else if (lflags & GPIO_V2_LINE_FLAG_INPUT) + clear_bit(FLAG_IS_OUT, &flags); - assign_bit(FLAG_EDGE_RISING, flagsp, - flags & GPIO_V2_LINE_FLAG_EDGE_RISING); - assign_bit(FLAG_EDGE_FALLING, flagsp, - flags & GPIO_V2_LINE_FLAG_EDGE_FALLING); + assign_bit(FLAG_EDGE_RISING, &flags, + lflags & GPIO_V2_LINE_FLAG_EDGE_RISING); + assign_bit(FLAG_EDGE_FALLING, &flags, + lflags & GPIO_V2_LINE_FLAG_EDGE_FALLING); - assign_bit(FLAG_OPEN_DRAIN, flagsp, - flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN); - assign_bit(FLAG_OPEN_SOURCE, flagsp, - flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE); + assign_bit(FLAG_OPEN_DRAIN, &flags, + lflags & GPIO_V2_LINE_FLAG_OPEN_DRAIN); + assign_bit(FLAG_OPEN_SOURCE, &flags, + lflags & GPIO_V2_LINE_FLAG_OPEN_SOURCE); - assign_bit(FLAG_PULL_UP, flagsp, - flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP); - assign_bit(FLAG_PULL_DOWN, flagsp, - flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN); - assign_bit(FLAG_BIAS_DISABLE, flagsp, - flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED); + assign_bit(FLAG_PULL_UP, &flags, + lflags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP); + assign_bit(FLAG_PULL_DOWN, &flags, + lflags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN); + assign_bit(FLAG_BIAS_DISABLE, &flags, + lflags & GPIO_V2_LINE_FLAG_BIAS_DISABLED); - assign_bit(FLAG_EVENT_CLOCK_REALTIME, flagsp, - flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME); - assign_bit(FLAG_EVENT_CLOCK_HTE, flagsp, - flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE); + assign_bit(FLAG_EVENT_CLOCK_REALTIME, &flags, + lflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME); + assign_bit(FLAG_EVENT_CLOCK_HTE, &flags, + lflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE); + + WRITE_ONCE(*flagsp, flags); } static long linereq_get_values(struct linereq *lr, void __user *ip) @@ -1460,9 +1366,6 @@ static long linereq_set_values(struct linereq *lr, void __user *ip) /* scan requested lines to determine the subset to be set */ for (num_set = 0, i = 0; i < lr->num_lines; i++) { if (lv.mask & BIT_ULL(i)) { - /* setting inputs is not allowed */ - if (!test_bit(FLAG_IS_OUT, &lr->lines[i].desc->flags)) - return -EPERM; /* add to compacted values */ if (lv.bits & BIT_ULL(i)) __set_bit(num_set, vals); @@ -1516,21 +1419,23 @@ static long linereq_set_config(struct linereq *lr, void __user *ip) line = &lr->lines[i]; desc = lr->lines[i].desc; flags = gpio_v2_line_config_flags(&lc, i); - gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags); - edflags = flags & GPIO_V2_LINE_EDGE_DETECTOR_FLAGS; /* - * Lines have to be requested explicitly for input - * or output, else the line will be treated "as is". + * Lines not explicitly reconfigured as input or output + * are left unchanged. */ + if (!(flags & GPIO_V2_LINE_DIRECTION_FLAGS)) + continue; + gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags); + edflags = flags & GPIO_V2_LINE_EDGE_DETECTOR_FLAGS; if (flags & GPIO_V2_LINE_FLAG_OUTPUT) { int val = gpio_v2_line_config_output_value(&lc, i); edge_detector_stop(line); - ret = gpiod_direction_output(desc, val); + ret = gpiod_direction_output_nonotify(desc, val); if (ret) return ret; - } else if (flags & GPIO_V2_LINE_FLAG_INPUT) { - ret = gpiod_direction_input(desc); + } else { + ret = gpiod_direction_input_nonotify(desc); if (ret) return ret; @@ -1628,16 +1533,15 @@ static ssize_t linereq_read(struct file *file, char __user *buf, return ret; } - ret = kfifo_out(&lr->events, &le, 1); - } - if (ret != 1) { - /* - * This should never happen - we were holding the - * lock from the moment we learned the fifo is no - * longer empty until now. - */ - ret = -EIO; - break; + if (kfifo_out(&lr->events, &le, 1) != 1) { + /* + * This should never happen - we hold the + * lock from the moment we learned the fifo + * is no longer empty until now. + */ + WARN(1, "failed to read from non-empty kfifo"); + return -EIO; + } } if (copy_to_user(buf + bytes_read, &le, sizeof(le))) @@ -1650,7 +1554,6 @@ static ssize_t linereq_read(struct file *file, char __user *buf, static void linereq_free(struct linereq *lr) { - struct line *line; unsigned int i; if (lr->device_unregistered_nb.notifier_call) @@ -1658,14 +1561,10 @@ static void linereq_free(struct linereq *lr) &lr->device_unregistered_nb); for (i = 0; i < lr->num_lines; i++) { - line = &lr->lines[i]; - if (!line->desc) - continue; - - edge_detector_stop(line); - if (line_has_supinfo(line)) - supinfo_erase(line); - gpiod_free(line->desc); + if (lr->lines[i].desc) { + edge_detector_stop(&lr->lines[i]); + gpiod_free(lr->lines[i].desc); + } } kfifo_free(&lr->events); kfree(lr->label); @@ -1727,7 +1626,7 @@ static int linereq_create(struct gpio_device *gdev, void __user *ip) if ((ulr.num_lines == 0) || (ulr.num_lines > GPIO_V2_LINES_MAX)) return -EINVAL; - if (memchr_inv(ulr.padding, 0, sizeof(ulr.padding))) + if (!mem_is_zero(ulr.padding, sizeof(ulr.padding))) return -EINVAL; lc = &ulr.config; @@ -1760,6 +1659,7 @@ static int linereq_create(struct gpio_device *gdev, void __user *ip) mutex_init(&lr->config_mutex); init_waitqueue_head(&lr->wait); + INIT_KFIFO(lr->events); lr->event_buffer_size = ulr.event_buffer_size; if (lr->event_buffer_size == 0) lr->event_buffer_size = ulr.num_lines * 16; @@ -1798,11 +1698,11 @@ static int linereq_create(struct gpio_device *gdev, void __user *ip) if (flags & GPIO_V2_LINE_FLAG_OUTPUT) { int val = gpio_v2_line_config_output_value(lc, i); - ret = gpiod_direction_output(desc, val); + ret = gpiod_direction_output_nonotify(desc, val); if (ret) goto out_free_linereq; } else if (flags & GPIO_V2_LINE_FLAG_INPUT) { - ret = gpiod_direction_input(desc); + ret = gpiod_direction_input_nonotify(desc); if (ret) goto out_free_linereq; @@ -1980,16 +1880,15 @@ static ssize_t lineevent_read(struct file *file, char __user *buf, return ret; } - ret = kfifo_out(&le->events, &ge, 1); - } - if (ret != 1) { - /* - * This should never happen - we were holding the lock - * from the moment we learned the fifo is no longer - * empty until now. - */ - ret = -EIO; - break; + if (kfifo_out(&le->events, &ge, 1) != 1) { + /* + * This should never happen - we hold the + * lock from the moment we learned the fifo + * is no longer empty until now. + */ + WARN(1, "failed to read from non-empty kfifo"); + return -EIO; + } } if (copy_to_user(buf + bytes_read, &ge, ge_size)) @@ -2334,8 +2233,9 @@ static void gpio_v2_line_info_changed_to_v1( #endif /* CONFIG_GPIO_CDEV_V1 */ static void gpio_desc_to_lineinfo(struct gpio_desc *desc, - struct gpio_v2_line_info *info) + struct gpio_v2_line_info *info, bool atomic) { + u32 debounce_period_us; unsigned long dflags; const char *label; @@ -2351,7 +2251,7 @@ static void gpio_desc_to_lineinfo(struct gpio_desc *desc, dflags = READ_ONCE(desc->flags); - scoped_guard(srcu, &desc->srcu) { + scoped_guard(srcu, &desc->gdev->desc_srcu) { label = gpiod_get_label(desc); if (label && test_bit(FLAG_REQUESTED, &dflags)) strscpy(info->consumer, label, @@ -2372,12 +2272,14 @@ static void gpio_desc_to_lineinfo(struct gpio_desc *desc, */ if (test_bit(FLAG_REQUESTED, &dflags) || test_bit(FLAG_IS_HOGGED, &dflags) || - test_bit(FLAG_USED_AS_IRQ, &dflags) || test_bit(FLAG_EXPORT, &dflags) || test_bit(FLAG_SYSFS, &dflags) || - !gpiochip_line_is_valid(guard.gc, info->offset) || - !pinctrl_gpio_can_use_line(guard.gc, info->offset)) + !gpiochip_line_is_valid(guard.gc, info->offset)) { info->flags |= GPIO_V2_LINE_FLAG_USED; + } else if (!atomic) { + if (!pinctrl_gpio_can_use_line(guard.gc, info->offset)) + info->flags |= GPIO_V2_LINE_FLAG_USED; + } if (test_bit(FLAG_IS_OUT, &dflags)) info->flags |= GPIO_V2_LINE_FLAG_OUTPUT; @@ -2408,6 +2310,14 @@ static void gpio_desc_to_lineinfo(struct gpio_desc *desc, info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME; else if (test_bit(FLAG_EVENT_CLOCK_HTE, &dflags)) info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE; + + debounce_period_us = READ_ONCE(desc->debounce_period_us); + if (debounce_period_us) { + info->attrs[info->num_attrs].id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE; + info->attrs[info->num_attrs].debounce_period_us = + debounce_period_us; + info->num_attrs++; + } } struct gpio_chardev_data { @@ -2420,6 +2330,7 @@ struct gpio_chardev_data { #ifdef CONFIG_GPIO_CDEV_V1 atomic_t watch_abi_version; #endif + struct file *fp; }; static int chipinfo_get(struct gpio_chardev_data *cdev, void __user *ip) @@ -2475,7 +2386,7 @@ static int lineinfo_get_v1(struct gpio_chardev_data *cdev, void __user *ip, return -EBUSY; } - gpio_desc_to_lineinfo(desc, &lineinfo_v2); + gpio_desc_to_lineinfo(desc, &lineinfo_v2, false); gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo); if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) { @@ -2497,7 +2408,7 @@ static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip, if (copy_from_user(&lineinfo, ip, sizeof(lineinfo))) return -EFAULT; - if (memchr_inv(lineinfo.padding, 0, sizeof(lineinfo.padding))) + if (!mem_is_zero(lineinfo.padding, sizeof(lineinfo.padding))) return -EINVAL; desc = gpio_device_get_desc(cdev->gdev, lineinfo.offset); @@ -2512,8 +2423,7 @@ static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip, if (test_and_set_bit(lineinfo.offset, cdev->watched_lines)) return -EBUSY; } - gpio_desc_to_lineinfo(desc, &lineinfo); - supinfo_to_lineinfo(desc, &lineinfo); + gpio_desc_to_lineinfo(desc, &lineinfo, false); if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) { if (watch) @@ -2590,29 +2500,86 @@ static long gpio_ioctl_compat(struct file *file, unsigned int cmd, } #endif +struct lineinfo_changed_ctx { + struct work_struct work; + struct gpio_v2_line_info_changed chg; + struct gpio_device *gdev; + struct gpio_chardev_data *cdev; +}; + +static void lineinfo_changed_func(struct work_struct *work) +{ + struct lineinfo_changed_ctx *ctx = + container_of(work, struct lineinfo_changed_ctx, work); + struct gpio_chip *gc; + int ret; + + if (!(ctx->chg.info.flags & GPIO_V2_LINE_FLAG_USED)) { + /* + * If nobody set the USED flag earlier, let's see with pinctrl + * now. We're doing this late because it's a sleeping function. + * Pin functions are in general much more static and while it's + * not 100% bullet-proof, it's good enough for most cases. + */ + scoped_guard(srcu, &ctx->gdev->srcu) { + gc = srcu_dereference(ctx->gdev->chip, &ctx->gdev->srcu); + if (gc && + !pinctrl_gpio_can_use_line(gc, ctx->chg.info.offset)) + ctx->chg.info.flags |= GPIO_V2_LINE_FLAG_USED; + } + } + + ret = kfifo_in_spinlocked(&ctx->cdev->events, &ctx->chg, 1, + &ctx->cdev->wait.lock); + if (ret) + wake_up_poll(&ctx->cdev->wait, EPOLLIN); + else + pr_debug_ratelimited("lineinfo event FIFO is full - event dropped\n"); + + gpio_device_put(ctx->gdev); + fput(ctx->cdev->fp); + kfree(ctx); +} + static int lineinfo_changed_notify(struct notifier_block *nb, unsigned long action, void *data) { struct gpio_chardev_data *cdev = container_of(nb, struct gpio_chardev_data, lineinfo_changed_nb); - struct gpio_v2_line_info_changed chg; + struct lineinfo_changed_ctx *ctx; struct gpio_desc *desc = data; - int ret; if (!test_bit(gpio_chip_hwgpio(desc), cdev->watched_lines)) return NOTIFY_DONE; - memset(&chg, 0, sizeof(chg)); - chg.event_type = action; - chg.timestamp_ns = ktime_get_ns(); - gpio_desc_to_lineinfo(desc, &chg.info); - supinfo_to_lineinfo(desc, &chg.info); + /* + * If this is called from atomic context (for instance: with a spinlock + * taken by the atomic notifier chain), any sleeping calls must be done + * outside of this function in process context of the dedicated + * workqueue. + * + * Let's gather as much info as possible from the descriptor and + * postpone just the call to pinctrl_gpio_can_use_line() until the work + * is executed. + */ + + ctx = kzalloc(sizeof(*ctx), GFP_ATOMIC); + if (!ctx) { + pr_err("Failed to allocate memory for line info notification\n"); + return NOTIFY_DONE; + } + + ctx->chg.event_type = action; + ctx->chg.timestamp_ns = ktime_get_ns(); + gpio_desc_to_lineinfo(desc, &ctx->chg.info, true); + /* Keep the GPIO device alive until we emit the event. */ + ctx->gdev = gpio_device_get(desc->gdev); + ctx->cdev = cdev; + /* Keep the file descriptor alive too. */ + get_file(ctx->cdev->fp); - ret = kfifo_in_spinlocked(&cdev->events, &chg, 1, &cdev->wait.lock); - if (ret) - wake_up_poll(&cdev->wait, EPOLLIN); - else - pr_debug_ratelimited("lineinfo event FIFO is full - event dropped\n"); + INIT_WORK(&ctx->work, lineinfo_changed_func); + queue_work(ctx->gdev->line_state_wq, &ctx->work); return NOTIFY_OK; } @@ -2692,12 +2659,15 @@ static ssize_t lineinfo_watch_read(struct file *file, char __user *buf, if (count < event_size) return -EINVAL; #endif - ret = kfifo_out(&cdev->events, &event, 1); - } - if (ret != 1) { - ret = -EIO; - break; - /* We should never get here. See lineevent_read(). */ + if (kfifo_out(&cdev->events, &event, 1) != 1) { + /* + * This should never happen - we hold the + * lock from the moment we learned the fifo + * is no longer empty until now. + */ + WARN(1, "failed to read from non-empty kfifo"); + return -EIO; + } } #ifdef CONFIG_GPIO_CDEV_V1 @@ -2726,7 +2696,9 @@ static ssize_t lineinfo_watch_read(struct file *file, char __user *buf, * gpio_chrdev_open() - open the chardev for ioctl operations * @inode: inode for this chardev * @file: file struct for storing private data - * Returns 0 on success + * + * Returns: + * 0 on success, or negative errno on failure. */ static int gpio_chrdev_open(struct inode *inode, struct file *file) { @@ -2754,8 +2726,9 @@ static int gpio_chrdev_open(struct inode *inode, struct file *file) cdev->gdev = gpio_device_get(gdev); cdev->lineinfo_changed_nb.notifier_call = lineinfo_changed_notify; - ret = blocking_notifier_chain_register(&gdev->line_state_notifier, - &cdev->lineinfo_changed_nb); + scoped_guard(write_lock_irqsave, &gdev->line_state_lock) + ret = raw_notifier_chain_register(&gdev->line_state_notifier, + &cdev->lineinfo_changed_nb); if (ret) goto out_free_bitmap; @@ -2767,6 +2740,7 @@ static int gpio_chrdev_open(struct inode *inode, struct file *file) goto out_unregister_line_notifier; file->private_data = cdev; + cdev->fp = file; ret = nonseekable_open(inode, file); if (ret) @@ -2778,8 +2752,9 @@ out_unregister_device_notifier: blocking_notifier_chain_unregister(&gdev->device_notifier, &cdev->device_unregistered_nb); out_unregister_line_notifier: - blocking_notifier_chain_unregister(&gdev->line_state_notifier, - &cdev->lineinfo_changed_nb); + scoped_guard(write_lock_irqsave, &gdev->line_state_lock) + raw_notifier_chain_unregister(&gdev->line_state_notifier, + &cdev->lineinfo_changed_nb); out_free_bitmap: gpio_device_put(gdev); bitmap_free(cdev->watched_lines); @@ -2792,18 +2767,21 @@ out_free_cdev: * gpio_chrdev_release() - close chardev after ioctl operations * @inode: inode for this chardev * @file: file struct for storing private data - * Returns 0 on success + * + * Returns: + * 0 on success, or negative errno on failure. */ static int gpio_chrdev_release(struct inode *inode, struct file *file) { struct gpio_chardev_data *cdev = file->private_data; struct gpio_device *gdev = cdev->gdev; - bitmap_free(cdev->watched_lines); blocking_notifier_chain_unregister(&gdev->device_notifier, &cdev->device_unregistered_nb); - blocking_notifier_chain_unregister(&gdev->line_state_notifier, - &cdev->lineinfo_changed_nb); + scoped_guard(write_lock_irqsave, &gdev->line_state_lock) + raw_notifier_chain_unregister(&gdev->line_state_notifier, + &cdev->lineinfo_changed_nb); + bitmap_free(cdev->watched_lines); gpio_device_put(gdev); kfree(cdev); @@ -2816,7 +2794,6 @@ static const struct file_operations gpio_fileops = { .poll = lineinfo_watch_poll, .read = lineinfo_watch_read, .owner = THIS_MODULE, - .llseek = no_llseek, .unlocked_ioctl = gpio_ioctl, #ifdef CONFIG_COMPAT .compat_ioctl = gpio_ioctl_compat, @@ -2832,6 +2809,11 @@ int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt) gdev->chrdev.owner = THIS_MODULE; gdev->dev.devt = MKDEV(MAJOR(devt), gdev->id); + gdev->line_state_wq = alloc_ordered_workqueue("%s", WQ_HIGHPRI, + dev_name(&gdev->dev)); + if (!gdev->line_state_wq) + return -ENOMEM; + ret = cdev_device_add(&gdev->chrdev, &gdev->dev); if (ret) return ret; @@ -2848,6 +2830,7 @@ int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt) void gpiolib_cdev_unregister(struct gpio_device *gdev) { + destroy_workqueue(gdev->line_state_wq); cdev_device_del(&gdev->chrdev, &gdev->dev); blocking_notifier_call_chain(&gdev->device_notifier, 0, NULL); } |