Update Linux to v5.10.109
Sourced from [1]
[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.10.109.tar.xz
Change-Id: I19bca9fc6762d4e63bcf3e4cba88bbe560d9c76c
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
new file mode 100644
index 0000000..2613881
--- /dev/null
+++ b/drivers/gpio/gpiolib-cdev.c
@@ -0,0 +1,2359 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/anon_inodes.h>
+#include <linux/atomic.h>
+#include <linux/bitmap.h>
+#include <linux/build_bug.h>
+#include <linux/cdev.h>
+#include <linux/compat.h>
+#include <linux/compiler.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/file.h>
+#include <linux/gpio.h>
+#include <linux/gpio/driver.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/pinctrl/consumer.h>
+#include <linux/poll.h>
+#include <linux/spinlock.h>
+#include <linux/timekeeping.h>
+#include <linux/uaccess.h>
+#include <linux/workqueue.h>
+#include <uapi/linux/gpio.h>
+
+#include "gpiolib.h"
+#include "gpiolib-cdev.h"
+
+/*
+ * Array sizes must ensure 64-bit alignment and not create holes in the
+ * struct packing.
+ */
+static_assert(IS_ALIGNED(GPIO_V2_LINES_MAX, 2));
+static_assert(IS_ALIGNED(GPIO_MAX_NAME_SIZE, 8));
+
+/*
+ * Check that uAPI structs are 64-bit aligned for 32/64-bit compatibility
+ */
+static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_attribute), 8));
+static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config_attribute), 8));
+static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config), 8));
+static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_request), 8));
+static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info), 8));
+static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info_changed), 8));
+static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_event), 8));
+static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_values), 8));
+
+/* Character device interface to GPIO.
+ *
+ * The GPIO character device, /dev/gpiochipN, provides userspace an
+ * interface to gpiolib GPIOs via ioctl()s.
+ */
+
+/*
+ * GPIO line handle management
+ */
+
+#ifdef CONFIG_GPIO_CDEV_V1
+/**
+ * struct linehandle_state - contains the state of a userspace handle
+ * @gdev: the GPIO device the handle pertains to
+ * @label: consumer label used to tag descriptors
+ * @descs: the GPIO descriptors held by this handle
+ * @num_descs: the number of descriptors held in the descs array
+ */
+struct linehandle_state {
+ struct gpio_device *gdev;
+ const char *label;
+ struct gpio_desc *descs[GPIOHANDLES_MAX];
+ u32 num_descs;
+};
+
+#define GPIOHANDLE_REQUEST_VALID_FLAGS \
+ (GPIOHANDLE_REQUEST_INPUT | \
+ GPIOHANDLE_REQUEST_OUTPUT | \
+ GPIOHANDLE_REQUEST_ACTIVE_LOW | \
+ GPIOHANDLE_REQUEST_BIAS_PULL_UP | \
+ GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | \
+ GPIOHANDLE_REQUEST_BIAS_DISABLE | \
+ GPIOHANDLE_REQUEST_OPEN_DRAIN | \
+ GPIOHANDLE_REQUEST_OPEN_SOURCE)
+
+static int linehandle_validate_flags(u32 flags)
+{
+ /* Return an error if an unknown flag is set */
+ if (flags & ~GPIOHANDLE_REQUEST_VALID_FLAGS)
+ return -EINVAL;
+
+ /*
+ * Do not allow both INPUT & OUTPUT flags to be set as they are
+ * contradictory.
+ */
+ if ((flags & GPIOHANDLE_REQUEST_INPUT) &&
+ (flags & GPIOHANDLE_REQUEST_OUTPUT))
+ return -EINVAL;
+
+ /*
+ * Do not allow OPEN_SOURCE & OPEN_DRAIN flags in a single request. If
+ * the hardware actually supports enabling both at the same time the
+ * electrical result would be disastrous.
+ */
+ if ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) &&
+ (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE))
+ return -EINVAL;
+
+ /* OPEN_DRAIN and OPEN_SOURCE flags only make sense for output mode. */
+ if (!(flags & GPIOHANDLE_REQUEST_OUTPUT) &&
+ ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
+ (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE)))
+ return -EINVAL;
+
+ /* Bias flags only allowed for input or output mode. */
+ if (!((flags & GPIOHANDLE_REQUEST_INPUT) ||
+ (flags & GPIOHANDLE_REQUEST_OUTPUT)) &&
+ ((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) ||
+ (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP) ||
+ (flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN)))
+ return -EINVAL;
+
+ /* Only one bias flag can be set. */
+ if (((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) &&
+ (flags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN |
+ GPIOHANDLE_REQUEST_BIAS_PULL_UP))) ||
+ ((flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) &&
+ (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)))
+ return -EINVAL;
+
+ return 0;
+}
+
+static void linehandle_flags_to_desc_flags(u32 lflags, unsigned long *flagsp)
+{
+ assign_bit(FLAG_ACTIVE_LOW, flagsp,
+ lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW);
+ assign_bit(FLAG_OPEN_DRAIN, flagsp,
+ lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN);
+ assign_bit(FLAG_OPEN_SOURCE, flagsp,
+ lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE);
+ assign_bit(FLAG_PULL_UP, flagsp,
+ lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP);
+ assign_bit(FLAG_PULL_DOWN, flagsp,
+ lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN);
+ assign_bit(FLAG_BIAS_DISABLE, flagsp,
+ lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE);
+}
+
+static long linehandle_set_config(struct linehandle_state *lh,
+ void __user *ip)
+{
+ struct gpiohandle_config gcnf;
+ struct gpio_desc *desc;
+ int i, ret;
+ u32 lflags;
+
+ if (copy_from_user(&gcnf, ip, sizeof(gcnf)))
+ return -EFAULT;
+
+ lflags = gcnf.flags;
+ ret = linehandle_validate_flags(lflags);
+ if (ret)
+ return ret;
+
+ for (i = 0; i < lh->num_descs; i++) {
+ desc = lh->descs[i];
+ linehandle_flags_to_desc_flags(gcnf.flags, &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);
+ if (ret)
+ return ret;
+ } else if (lflags & GPIOHANDLE_REQUEST_INPUT) {
+ ret = gpiod_direction_input(desc);
+ if (ret)
+ return ret;
+ }
+
+ blocking_notifier_call_chain(&desc->gdev->notifier,
+ GPIO_V2_LINE_CHANGED_CONFIG,
+ desc);
+ }
+ return 0;
+}
+
+static long linehandle_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ struct linehandle_state *lh = file->private_data;
+ void __user *ip = (void __user *)arg;
+ struct gpiohandle_data ghd;
+ DECLARE_BITMAP(vals, GPIOHANDLES_MAX);
+ int i;
+
+ if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) {
+ /* NOTE: It's ok to read values of output lines. */
+ int ret = gpiod_get_array_value_complex(false,
+ true,
+ lh->num_descs,
+ lh->descs,
+ NULL,
+ vals);
+ if (ret)
+ return ret;
+
+ memset(&ghd, 0, sizeof(ghd));
+ for (i = 0; i < lh->num_descs; i++)
+ ghd.values[i] = test_bit(i, vals);
+
+ if (copy_to_user(ip, &ghd, sizeof(ghd)))
+ return -EFAULT;
+
+ return 0;
+ } else if (cmd == GPIOHANDLE_SET_LINE_VALUES_IOCTL) {
+ /*
+ * All line descriptors were created at once with the same
+ * flags so just check if the first one is really output.
+ */
+ if (!test_bit(FLAG_IS_OUT, &lh->descs[0]->flags))
+ return -EPERM;
+
+ if (copy_from_user(&ghd, ip, sizeof(ghd)))
+ return -EFAULT;
+
+ /* Clamp all values to [0,1] */
+ for (i = 0; i < lh->num_descs; i++)
+ __assign_bit(i, vals, ghd.values[i]);
+
+ /* Reuse the array setting function */
+ return gpiod_set_array_value_complex(false,
+ true,
+ lh->num_descs,
+ lh->descs,
+ NULL,
+ vals);
+ } else if (cmd == GPIOHANDLE_SET_CONFIG_IOCTL) {
+ return linehandle_set_config(lh, ip);
+ }
+ return -EINVAL;
+}
+
+#ifdef CONFIG_COMPAT
+static long linehandle_ioctl_compat(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ return linehandle_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
+}
+#endif
+
+static void linehandle_free(struct linehandle_state *lh)
+{
+ int i;
+
+ for (i = 0; i < lh->num_descs; i++)
+ if (lh->descs[i])
+ gpiod_free(lh->descs[i]);
+ kfree(lh->label);
+ put_device(&lh->gdev->dev);
+ kfree(lh);
+}
+
+static int linehandle_release(struct inode *inode, struct file *file)
+{
+ linehandle_free(file->private_data);
+ return 0;
+}
+
+static const struct file_operations linehandle_fileops = {
+ .release = linehandle_release,
+ .owner = THIS_MODULE,
+ .llseek = noop_llseek,
+ .unlocked_ioctl = linehandle_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = linehandle_ioctl_compat,
+#endif
+};
+
+static int linehandle_create(struct gpio_device *gdev, void __user *ip)
+{
+ struct gpiohandle_request handlereq;
+ struct linehandle_state *lh;
+ struct file *file;
+ int fd, i, ret;
+ u32 lflags;
+
+ if (copy_from_user(&handlereq, ip, sizeof(handlereq)))
+ return -EFAULT;
+ if ((handlereq.lines == 0) || (handlereq.lines > GPIOHANDLES_MAX))
+ return -EINVAL;
+
+ lflags = handlereq.flags;
+
+ ret = linehandle_validate_flags(lflags);
+ if (ret)
+ return ret;
+
+ lh = kzalloc(sizeof(*lh), GFP_KERNEL);
+ if (!lh)
+ return -ENOMEM;
+ lh->gdev = gdev;
+ get_device(&gdev->dev);
+
+ if (handlereq.consumer_label[0] != '\0') {
+ /* label is only initialized if consumer_label is set */
+ lh->label = kstrndup(handlereq.consumer_label,
+ sizeof(handlereq.consumer_label) - 1,
+ GFP_KERNEL);
+ if (!lh->label) {
+ ret = -ENOMEM;
+ goto out_free_lh;
+ }
+ }
+
+ lh->num_descs = handlereq.lines;
+
+ /* Request each GPIO */
+ for (i = 0; i < handlereq.lines; i++) {
+ u32 offset = handlereq.lineoffsets[i];
+ struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset);
+
+ if (IS_ERR(desc)) {
+ ret = PTR_ERR(desc);
+ goto out_free_lh;
+ }
+
+ ret = gpiod_request(desc, lh->label);
+ if (ret)
+ goto out_free_lh;
+ lh->descs[i] = desc;
+ linehandle_flags_to_desc_flags(handlereq.flags, &desc->flags);
+
+ ret = gpiod_set_transitory(desc, false);
+ if (ret < 0)
+ goto out_free_lh;
+
+ /*
+ * 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 = !!handlereq.default_values[i];
+
+ ret = gpiod_direction_output(desc, val);
+ if (ret)
+ goto out_free_lh;
+ } else if (lflags & GPIOHANDLE_REQUEST_INPUT) {
+ ret = gpiod_direction_input(desc);
+ if (ret)
+ goto out_free_lh;
+ }
+
+ blocking_notifier_call_chain(&desc->gdev->notifier,
+ GPIO_V2_LINE_CHANGED_REQUESTED, desc);
+
+ dev_dbg(&gdev->dev, "registered chardev handle for line %d\n",
+ offset);
+ }
+
+ fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
+ if (fd < 0) {
+ ret = fd;
+ goto out_free_lh;
+ }
+
+ file = anon_inode_getfile("gpio-linehandle",
+ &linehandle_fileops,
+ lh,
+ O_RDONLY | O_CLOEXEC);
+ if (IS_ERR(file)) {
+ ret = PTR_ERR(file);
+ goto out_put_unused_fd;
+ }
+
+ handlereq.fd = fd;
+ if (copy_to_user(ip, &handlereq, sizeof(handlereq))) {
+ /*
+ * fput() will trigger the release() callback, so do not go onto
+ * the regular error cleanup path here.
+ */
+ fput(file);
+ put_unused_fd(fd);
+ return -EFAULT;
+ }
+
+ fd_install(fd, file);
+
+ dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n",
+ lh->num_descs);
+
+ return 0;
+
+out_put_unused_fd:
+ put_unused_fd(fd);
+out_free_lh:
+ linehandle_free(lh);
+ return ret;
+}
+#endif /* CONFIG_GPIO_CDEV_V1 */
+
+/**
+ * struct line - contains the state of a requested line
+ * @desc: the GPIO descriptor for this line.
+ * @req: the corresponding line request
+ * @irq: the interrupt triggered in response to events on this GPIO
+ * @eflags: the edge flags, GPIO_V2_LINE_FLAG_EDGE_RISING and/or
+ * GPIO_V2_LINE_FLAG_EDGE_FALLING, indicating the edge detection applied
+ * @timestamp_ns: cache for the timestamp storing it between hardirq and
+ * IRQ thread, used to bring the timestamp close to the actual event
+ * @req_seqno: the seqno for the current edge event in the sequence of
+ * events for the corresponding line request. This is drawn from the @req.
+ * @line_seqno: the seqno for the current edge event in the sequence of
+ * events for this line.
+ * @work: the worker that implements software debouncing
+ * @sw_debounced: flag indicating if the software debouncer is active
+ * @level: the current debounced physical level of the line
+ */
+struct line {
+ struct gpio_desc *desc;
+ /*
+ * -- edge detector specific fields --
+ */
+ struct linereq *req;
+ unsigned int irq;
+ u64 eflags;
+ /*
+ * timestamp_ns and req_seqno are accessed only by
+ * edge_irq_handler() and edge_irq_thread(), which are themselves
+ * mutually exclusive, so no additional protection is necessary.
+ */
+ u64 timestamp_ns;
+ u32 req_seqno;
+ /*
+ * line_seqno is accessed by either edge_irq_thread() or
+ * debounce_work_func(), which are themselves mutually exclusive,
+ * so no additional protection is necessary.
+ */
+ u32 line_seqno;
+ /*
+ * -- debouncer specific fields --
+ */
+ struct delayed_work work;
+ /*
+ * 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.
+ */
+ unsigned int sw_debounced;
+ /*
+ * level is accessed by debounce_work_func(), which is the only
+ * setter, and linereq_get_values() which can live with a slightly
+ * stale value.
+ */
+ unsigned int level;
+};
+
+/**
+ * struct linereq - contains the state of a userspace line request
+ * @gdev: the GPIO device the line request pertains to
+ * @label: consumer label used to tag GPIO descriptors
+ * @num_lines: the number of lines in the lines array
+ * @wait: wait queue that handles blocking reads of events
+ * @event_buffer_size: the number of elements allocated in @events
+ * @events: KFIFO for the GPIO events
+ * @seqno: the sequence number for edge events generated on all lines in
+ * 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.
+ * @lines: the lines held by this line request, with @num_lines elements.
+ */
+struct linereq {
+ struct gpio_device *gdev;
+ const char *label;
+ u32 num_lines;
+ wait_queue_head_t wait;
+ u32 event_buffer_size;
+ DECLARE_KFIFO_PTR(events, struct gpio_v2_line_event);
+ atomic_t seqno;
+ struct mutex config_mutex;
+ struct line lines[];
+};
+
+#define GPIO_V2_LINE_BIAS_FLAGS \
+ (GPIO_V2_LINE_FLAG_BIAS_PULL_UP | \
+ GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | \
+ GPIO_V2_LINE_FLAG_BIAS_DISABLED)
+
+#define GPIO_V2_LINE_DIRECTION_FLAGS \
+ (GPIO_V2_LINE_FLAG_INPUT | \
+ GPIO_V2_LINE_FLAG_OUTPUT)
+
+#define GPIO_V2_LINE_DRIVE_FLAGS \
+ (GPIO_V2_LINE_FLAG_OPEN_DRAIN | \
+ GPIO_V2_LINE_FLAG_OPEN_SOURCE)
+
+#define GPIO_V2_LINE_EDGE_FLAGS \
+ (GPIO_V2_LINE_FLAG_EDGE_RISING | \
+ GPIO_V2_LINE_FLAG_EDGE_FALLING)
+
+#define GPIO_V2_LINE_VALID_FLAGS \
+ (GPIO_V2_LINE_FLAG_ACTIVE_LOW | \
+ GPIO_V2_LINE_DIRECTION_FLAGS | \
+ GPIO_V2_LINE_DRIVE_FLAGS | \
+ GPIO_V2_LINE_EDGE_FLAGS | \
+ GPIO_V2_LINE_BIAS_FLAGS)
+
+static void linereq_put_event(struct linereq *lr,
+ struct gpio_v2_line_event *le)
+{
+ bool overflow = false;
+
+ spin_lock(&lr->wait.lock);
+ if (kfifo_is_full(&lr->events)) {
+ overflow = true;
+ kfifo_skip(&lr->events);
+ }
+ kfifo_in(&lr->events, le, 1);
+ spin_unlock(&lr->wait.lock);
+ if (!overflow)
+ wake_up_poll(&lr->wait, EPOLLIN);
+ else
+ pr_debug_ratelimited("event FIFO is full - event dropped\n");
+}
+
+static irqreturn_t edge_irq_thread(int irq, void *p)
+{
+ struct line *line = p;
+ struct linereq *lr = line->req;
+ struct gpio_v2_line_event le;
+
+ /* Do not leak kernel stack to userspace */
+ memset(&le, 0, sizeof(le));
+
+ if (line->timestamp_ns) {
+ le.timestamp_ns = line->timestamp_ns;
+ } else {
+ /*
+ * We may be running from a nested threaded interrupt in
+ * which case we didn't get the timestamp from
+ * edge_irq_handler().
+ */
+ le.timestamp_ns = ktime_get_ns();
+ if (lr->num_lines != 1)
+ line->req_seqno = atomic_inc_return(&lr->seqno);
+ }
+ line->timestamp_ns = 0;
+
+ if (line->eflags == (GPIO_V2_LINE_FLAG_EDGE_RISING |
+ GPIO_V2_LINE_FLAG_EDGE_FALLING)) {
+ int level = gpiod_get_value_cansleep(line->desc);
+
+ if (level)
+ /* Emit low-to-high event */
+ le.id = GPIO_V2_LINE_EVENT_RISING_EDGE;
+ else
+ /* Emit high-to-low event */
+ le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE;
+ } else if (line->eflags == GPIO_V2_LINE_FLAG_EDGE_RISING) {
+ /* Emit low-to-high event */
+ le.id = GPIO_V2_LINE_EVENT_RISING_EDGE;
+ } else if (line->eflags == GPIO_V2_LINE_FLAG_EDGE_FALLING) {
+ /* Emit high-to-low event */
+ le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE;
+ } else {
+ return IRQ_NONE;
+ }
+ line->line_seqno++;
+ le.line_seqno = line->line_seqno;
+ le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno;
+ le.offset = gpio_chip_hwgpio(line->desc);
+
+ linereq_put_event(lr, &le);
+
+ return IRQ_HANDLED;
+}
+
+static irqreturn_t edge_irq_handler(int irq, void *p)
+{
+ struct line *line = p;
+ struct linereq *lr = line->req;
+
+ /*
+ * Just store the timestamp in hardirq context so we get it as
+ * close in time as possible to the actual event.
+ */
+ line->timestamp_ns = ktime_get_ns();
+
+ if (lr->num_lines != 1)
+ line->req_seqno = atomic_inc_return(&lr->seqno);
+
+ return IRQ_WAKE_THREAD;
+}
+
+/*
+ * returns the current debounced logical value.
+ */
+static bool debounced_value(struct line *line)
+{
+ bool value;
+
+ /*
+ * minor race - debouncer may be stopped here, so edge_detector_stop()
+ * must leave the value unchanged so the following will read the level
+ * from when the debouncer was last running.
+ */
+ value = READ_ONCE(line->level);
+
+ if (test_bit(FLAG_ACTIVE_LOW, &line->desc->flags))
+ value = !value;
+
+ return value;
+}
+
+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->desc->debounce_period_us)));
+
+ return IRQ_HANDLED;
+}
+
+static void debounce_work_func(struct work_struct *work)
+{
+ struct gpio_v2_line_event le;
+ struct line *line = container_of(work, struct line, work.work);
+ struct linereq *lr;
+ int level;
+
+ level = gpiod_get_raw_value_cansleep(line->desc);
+ if (level < 0) {
+ pr_debug_ratelimited("debouncer failed to read line value\n");
+ return;
+ }
+
+ if (READ_ONCE(line->level) == level)
+ return;
+
+ WRITE_ONCE(line->level, level);
+
+ /* -- edge detection -- */
+ if (!line->eflags)
+ return;
+
+ /* switch from physical level to logical - if they differ */
+ if (test_bit(FLAG_ACTIVE_LOW, &line->desc->flags))
+ level = !level;
+
+ /* ignore edges that are not being monitored */
+ if (((line->eflags == GPIO_V2_LINE_FLAG_EDGE_RISING) && !level) ||
+ ((line->eflags == GPIO_V2_LINE_FLAG_EDGE_FALLING) && level))
+ return;
+
+ /* Do not leak kernel stack to userspace */
+ memset(&le, 0, sizeof(le));
+
+ lr = line->req;
+ le.timestamp_ns = ktime_get_ns();
+ le.offset = gpio_chip_hwgpio(line->desc);
+ line->line_seqno++;
+ le.line_seqno = line->line_seqno;
+ le.seqno = (lr->num_lines == 1) ?
+ le.line_seqno : atomic_inc_return(&lr->seqno);
+
+ if (level)
+ /* Emit low-to-high event */
+ le.id = GPIO_V2_LINE_EVENT_RISING_EDGE;
+ else
+ /* Emit high-to-low event */
+ le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE;
+
+ linereq_put_event(lr, &le);
+}
+
+static int debounce_setup(struct line *line,
+ unsigned int debounce_period_us)
+{
+ unsigned long irqflags;
+ int ret, level, irq;
+
+ /* try hardware */
+ ret = gpiod_set_debounce(line->desc, debounce_period_us);
+ if (!ret) {
+ WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
+ return ret;
+ }
+ if (ret != -ENOTSUPP)
+ return ret;
+
+ if (debounce_period_us) {
+ /* setup software debounce */
+ level = gpiod_get_raw_value_cansleep(line->desc);
+ if (level < 0)
+ return level;
+
+ irq = gpiod_to_irq(line->desc);
+ if (irq < 0)
+ return -ENXIO;
+
+ WRITE_ONCE(line->level, level);
+ irqflags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING;
+ ret = request_irq(irq, debounce_irq_handler, irqflags,
+ line->req->label, line);
+ if (ret)
+ return ret;
+
+ WRITE_ONCE(line->sw_debounced, 1);
+ line->irq = irq;
+ }
+ return 0;
+}
+
+static bool gpio_v2_line_config_debounced(struct gpio_v2_line_config *lc,
+ unsigned int line_idx)
+{
+ unsigned int i;
+ u64 mask = BIT_ULL(line_idx);
+
+ for (i = 0; i < lc->num_attrs; i++) {
+ if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) &&
+ (lc->attrs[i].mask & mask))
+ return true;
+ }
+ return false;
+}
+
+static u32 gpio_v2_line_config_debounce_period(struct gpio_v2_line_config *lc,
+ unsigned int line_idx)
+{
+ unsigned int i;
+ u64 mask = BIT_ULL(line_idx);
+
+ for (i = 0; i < lc->num_attrs; i++) {
+ if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) &&
+ (lc->attrs[i].mask & mask))
+ return lc->attrs[i].attr.debounce_period_us;
+ }
+ return 0;
+}
+
+static void edge_detector_stop(struct line *line)
+{
+ if (line->irq) {
+ free_irq(line->irq, line);
+ line->irq = 0;
+ }
+
+ cancel_delayed_work_sync(&line->work);
+ WRITE_ONCE(line->sw_debounced, 0);
+ line->eflags = 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_setup(struct line *line,
+ struct gpio_v2_line_config *lc,
+ unsigned int line_idx,
+ u64 eflags)
+{
+ u32 debounce_period_us;
+ unsigned long irqflags = 0;
+ int irq, ret;
+
+ if (eflags && !kfifo_initialized(&line->req->events)) {
+ ret = kfifo_alloc(&line->req->events,
+ line->req->event_buffer_size, GFP_KERNEL);
+ if (ret)
+ return ret;
+ }
+ line->eflags = eflags;
+ if (gpio_v2_line_config_debounced(lc, line_idx)) {
+ debounce_period_us = gpio_v2_line_config_debounce_period(lc, line_idx);
+ ret = debounce_setup(line, debounce_period_us);
+ if (ret)
+ return ret;
+ WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
+ }
+
+ /* detection disabled or sw debouncer will provide edge detection */
+ if (!eflags || READ_ONCE(line->sw_debounced))
+ return 0;
+
+ irq = gpiod_to_irq(line->desc);
+ if (irq < 0)
+ return -ENXIO;
+
+ if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING)
+ irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
+ IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
+ if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING)
+ irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
+ IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
+ irqflags |= IRQF_ONESHOT;
+
+ /* Request a thread to read the events */
+ ret = request_threaded_irq(irq, edge_irq_handler, edge_irq_thread,
+ irqflags, line->req->label, line);
+ if (ret)
+ return ret;
+
+ line->irq = irq;
+ return 0;
+}
+
+static int edge_detector_update(struct line *line,
+ struct gpio_v2_line_config *lc,
+ unsigned int line_idx,
+ u64 eflags, bool polarity_change)
+{
+ unsigned int debounce_period_us =
+ gpio_v2_line_config_debounce_period(lc, line_idx);
+
+ if ((line->eflags == eflags) && !polarity_change &&
+ (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->eflags = eflags;
+ WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
+ return 0;
+ }
+
+ /* reconfiguring edge detection or sw debounce being disabled */
+ if ((line->irq && !READ_ONCE(line->sw_debounced)) ||
+ (!debounce_period_us && READ_ONCE(line->sw_debounced)))
+ edge_detector_stop(line);
+
+ return edge_detector_setup(line, lc, line_idx, eflags);
+}
+
+static u64 gpio_v2_line_config_flags(struct gpio_v2_line_config *lc,
+ unsigned int line_idx)
+{
+ unsigned int i;
+ u64 mask = BIT_ULL(line_idx);
+
+ for (i = 0; i < lc->num_attrs; i++) {
+ if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_FLAGS) &&
+ (lc->attrs[i].mask & mask))
+ return lc->attrs[i].attr.flags;
+ }
+ return lc->flags;
+}
+
+static int gpio_v2_line_config_output_value(struct gpio_v2_line_config *lc,
+ unsigned int line_idx)
+{
+ unsigned int i;
+ u64 mask = BIT_ULL(line_idx);
+
+ for (i = 0; i < lc->num_attrs; i++) {
+ if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_OUTPUT_VALUES) &&
+ (lc->attrs[i].mask & mask))
+ return !!(lc->attrs[i].attr.values & mask);
+ }
+ return 0;
+}
+
+static int gpio_v2_line_flags_validate(u64 flags)
+{
+ /* Return an error if an unknown flag is set */
+ if (flags & ~GPIO_V2_LINE_VALID_FLAGS)
+ return -EINVAL;
+
+ /*
+ * Do not allow both INPUT and OUTPUT flags to be set as they are
+ * contradictory.
+ */
+ if ((flags & GPIO_V2_LINE_FLAG_INPUT) &&
+ (flags & GPIO_V2_LINE_FLAG_OUTPUT))
+ return -EINVAL;
+
+ /* Edge detection requires explicit input. */
+ if ((flags & GPIO_V2_LINE_EDGE_FLAGS) &&
+ !(flags & GPIO_V2_LINE_FLAG_INPUT))
+ return -EINVAL;
+
+ /*
+ * Do not allow OPEN_SOURCE and OPEN_DRAIN flags in a single
+ * request. If the hardware actually supports enabling both at the
+ * same time the electrical result would be disastrous.
+ */
+ if ((flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN) &&
+ (flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE))
+ return -EINVAL;
+
+ /* Drive requires explicit output direction. */
+ if ((flags & GPIO_V2_LINE_DRIVE_FLAGS) &&
+ !(flags & GPIO_V2_LINE_FLAG_OUTPUT))
+ return -EINVAL;
+
+ /* Bias requires explicit direction. */
+ if ((flags & GPIO_V2_LINE_BIAS_FLAGS) &&
+ !(flags & GPIO_V2_LINE_DIRECTION_FLAGS))
+ return -EINVAL;
+
+ /* Only one bias flag can be set. */
+ if (((flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED) &&
+ (flags & (GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN |
+ GPIO_V2_LINE_FLAG_BIAS_PULL_UP))) ||
+ ((flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) &&
+ (flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP)))
+ return -EINVAL;
+
+ return 0;
+}
+
+static int gpio_v2_line_config_validate(struct gpio_v2_line_config *lc,
+ unsigned int num_lines)
+{
+ unsigned int i;
+ u64 flags;
+ int ret;
+
+ if (lc->num_attrs > GPIO_V2_LINE_NUM_ATTRS_MAX)
+ return -EINVAL;
+
+ if (memchr_inv(lc->padding, 0, sizeof(lc->padding)))
+ return -EINVAL;
+
+ for (i = 0; i < num_lines; i++) {
+ flags = gpio_v2_line_config_flags(lc, i);
+ ret = gpio_v2_line_flags_validate(flags);
+ if (ret)
+ return ret;
+
+ /* debounce requires explicit input */
+ if (gpio_v2_line_config_debounced(lc, i) &&
+ !(flags & GPIO_V2_LINE_FLAG_INPUT))
+ return -EINVAL;
+ }
+ return 0;
+}
+
+static void gpio_v2_line_config_flags_to_desc_flags(u64 flags,
+ unsigned long *flagsp)
+{
+ assign_bit(FLAG_ACTIVE_LOW, flagsp,
+ flags & 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);
+
+ 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_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_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);
+}
+
+static long linereq_get_values(struct linereq *lr, void __user *ip)
+{
+ struct gpio_v2_line_values lv;
+ DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX);
+ struct gpio_desc **descs;
+ unsigned int i, didx, num_get;
+ bool val;
+ int ret;
+
+ /* NOTE: It's ok to read values of output lines. */
+ if (copy_from_user(&lv, ip, sizeof(lv)))
+ return -EFAULT;
+
+ for (num_get = 0, i = 0; i < lr->num_lines; i++) {
+ if (lv.mask & BIT_ULL(i)) {
+ num_get++;
+ descs = &lr->lines[i].desc;
+ }
+ }
+
+ if (num_get == 0)
+ return -EINVAL;
+
+ if (num_get != 1) {
+ descs = kmalloc_array(num_get, sizeof(*descs), GFP_KERNEL);
+ if (!descs)
+ return -ENOMEM;
+ for (didx = 0, i = 0; i < lr->num_lines; i++) {
+ if (lv.mask & BIT_ULL(i)) {
+ descs[didx] = lr->lines[i].desc;
+ didx++;
+ }
+ }
+ }
+ ret = gpiod_get_array_value_complex(false, true, num_get,
+ descs, NULL, vals);
+
+ if (num_get != 1)
+ kfree(descs);
+ if (ret)
+ return ret;
+
+ lv.bits = 0;
+ for (didx = 0, i = 0; i < lr->num_lines; i++) {
+ if (lv.mask & BIT_ULL(i)) {
+ if (lr->lines[i].sw_debounced)
+ val = debounced_value(&lr->lines[i]);
+ else
+ val = test_bit(didx, vals);
+ if (val)
+ lv.bits |= BIT_ULL(i);
+ didx++;
+ }
+ }
+
+ if (copy_to_user(ip, &lv, sizeof(lv)))
+ return -EFAULT;
+
+ return 0;
+}
+
+static long linereq_set_values_unlocked(struct linereq *lr,
+ struct gpio_v2_line_values *lv)
+{
+ DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX);
+ struct gpio_desc **descs;
+ unsigned int i, didx, num_set;
+ int ret;
+
+ bitmap_zero(vals, GPIO_V2_LINES_MAX);
+ for (num_set = 0, i = 0; i < lr->num_lines; i++) {
+ if (lv->mask & BIT_ULL(i)) {
+ if (!test_bit(FLAG_IS_OUT, &lr->lines[i].desc->flags))
+ return -EPERM;
+ if (lv->bits & BIT_ULL(i))
+ __set_bit(num_set, vals);
+ num_set++;
+ descs = &lr->lines[i].desc;
+ }
+ }
+ if (num_set == 0)
+ return -EINVAL;
+
+ if (num_set != 1) {
+ /* build compacted desc array and values */
+ descs = kmalloc_array(num_set, sizeof(*descs), GFP_KERNEL);
+ if (!descs)
+ return -ENOMEM;
+ for (didx = 0, i = 0; i < lr->num_lines; i++) {
+ if (lv->mask & BIT_ULL(i)) {
+ descs[didx] = lr->lines[i].desc;
+ didx++;
+ }
+ }
+ }
+ ret = gpiod_set_array_value_complex(false, true, num_set,
+ descs, NULL, vals);
+
+ if (num_set != 1)
+ kfree(descs);
+ return ret;
+}
+
+static long linereq_set_values(struct linereq *lr, void __user *ip)
+{
+ struct gpio_v2_line_values lv;
+ int ret;
+
+ if (copy_from_user(&lv, ip, sizeof(lv)))
+ return -EFAULT;
+
+ mutex_lock(&lr->config_mutex);
+
+ ret = linereq_set_values_unlocked(lr, &lv);
+
+ mutex_unlock(&lr->config_mutex);
+
+ return ret;
+}
+
+static long linereq_set_config_unlocked(struct linereq *lr,
+ struct gpio_v2_line_config *lc)
+{
+ struct gpio_desc *desc;
+ unsigned int i;
+ u64 flags;
+ bool polarity_change;
+ int ret;
+
+ for (i = 0; i < lr->num_lines; i++) {
+ desc = lr->lines[i].desc;
+ flags = gpio_v2_line_config_flags(lc, i);
+ polarity_change =
+ (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) !=
+ ((flags & GPIO_V2_LINE_FLAG_ACTIVE_LOW) != 0));
+
+ gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags);
+ /*
+ * Lines have to be requested explicitly for input
+ * or output, else the line will be treated "as is".
+ */
+ if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
+ int val = gpio_v2_line_config_output_value(lc, i);
+
+ edge_detector_stop(&lr->lines[i]);
+ ret = gpiod_direction_output(desc, val);
+ if (ret)
+ return ret;
+ } else if (flags & GPIO_V2_LINE_FLAG_INPUT) {
+ ret = gpiod_direction_input(desc);
+ if (ret)
+ return ret;
+
+ ret = edge_detector_update(&lr->lines[i], lc, i,
+ flags & GPIO_V2_LINE_EDGE_FLAGS,
+ polarity_change);
+ if (ret)
+ return ret;
+ }
+
+ blocking_notifier_call_chain(&desc->gdev->notifier,
+ GPIO_V2_LINE_CHANGED_CONFIG,
+ desc);
+ }
+ return 0;
+}
+
+static long linereq_set_config(struct linereq *lr, void __user *ip)
+{
+ struct gpio_v2_line_config lc;
+ int ret;
+
+ if (copy_from_user(&lc, ip, sizeof(lc)))
+ return -EFAULT;
+
+ ret = gpio_v2_line_config_validate(&lc, lr->num_lines);
+ if (ret)
+ return ret;
+
+ mutex_lock(&lr->config_mutex);
+
+ ret = linereq_set_config_unlocked(lr, &lc);
+
+ mutex_unlock(&lr->config_mutex);
+
+ return ret;
+}
+
+static long linereq_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ struct linereq *lr = file->private_data;
+ void __user *ip = (void __user *)arg;
+
+ if (cmd == GPIO_V2_LINE_GET_VALUES_IOCTL)
+ return linereq_get_values(lr, ip);
+ else if (cmd == GPIO_V2_LINE_SET_VALUES_IOCTL)
+ return linereq_set_values(lr, ip);
+ else if (cmd == GPIO_V2_LINE_SET_CONFIG_IOCTL)
+ return linereq_set_config(lr, ip);
+
+ return -EINVAL;
+}
+
+#ifdef CONFIG_COMPAT
+static long linereq_ioctl_compat(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ return linereq_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
+}
+#endif
+
+static __poll_t linereq_poll(struct file *file,
+ struct poll_table_struct *wait)
+{
+ struct linereq *lr = file->private_data;
+ __poll_t events = 0;
+
+ poll_wait(file, &lr->wait, wait);
+
+ if (!kfifo_is_empty_spinlocked_noirqsave(&lr->events,
+ &lr->wait.lock))
+ events = EPOLLIN | EPOLLRDNORM;
+
+ return events;
+}
+
+static ssize_t linereq_read(struct file *file,
+ char __user *buf,
+ size_t count,
+ loff_t *f_ps)
+{
+ struct linereq *lr = file->private_data;
+ struct gpio_v2_line_event le;
+ ssize_t bytes_read = 0;
+ int ret;
+
+ if (count < sizeof(le))
+ return -EINVAL;
+
+ do {
+ spin_lock(&lr->wait.lock);
+ if (kfifo_is_empty(&lr->events)) {
+ if (bytes_read) {
+ spin_unlock(&lr->wait.lock);
+ return bytes_read;
+ }
+
+ if (file->f_flags & O_NONBLOCK) {
+ spin_unlock(&lr->wait.lock);
+ return -EAGAIN;
+ }
+
+ ret = wait_event_interruptible_locked(lr->wait,
+ !kfifo_is_empty(&lr->events));
+ if (ret) {
+ spin_unlock(&lr->wait.lock);
+ return ret;
+ }
+ }
+
+ ret = kfifo_out(&lr->events, &le, 1);
+ spin_unlock(&lr->wait.lock);
+ 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 (copy_to_user(buf + bytes_read, &le, sizeof(le)))
+ return -EFAULT;
+ bytes_read += sizeof(le);
+ } while (count >= bytes_read + sizeof(le));
+
+ return bytes_read;
+}
+
+static void linereq_free(struct linereq *lr)
+{
+ unsigned int i;
+
+ for (i = 0; i < lr->num_lines; i++) {
+ edge_detector_stop(&lr->lines[i]);
+ if (lr->lines[i].desc)
+ gpiod_free(lr->lines[i].desc);
+ }
+ kfifo_free(&lr->events);
+ kfree(lr->label);
+ put_device(&lr->gdev->dev);
+ kfree(lr);
+}
+
+static int linereq_release(struct inode *inode, struct file *file)
+{
+ struct linereq *lr = file->private_data;
+
+ linereq_free(lr);
+ return 0;
+}
+
+static const struct file_operations line_fileops = {
+ .release = linereq_release,
+ .read = linereq_read,
+ .poll = linereq_poll,
+ .owner = THIS_MODULE,
+ .llseek = noop_llseek,
+ .unlocked_ioctl = linereq_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = linereq_ioctl_compat,
+#endif
+};
+
+static int linereq_create(struct gpio_device *gdev, void __user *ip)
+{
+ struct gpio_v2_line_request ulr;
+ struct gpio_v2_line_config *lc;
+ struct linereq *lr;
+ struct file *file;
+ u64 flags;
+ unsigned int i;
+ int fd, ret;
+
+ if (copy_from_user(&ulr, ip, sizeof(ulr)))
+ return -EFAULT;
+
+ if ((ulr.num_lines == 0) || (ulr.num_lines > GPIO_V2_LINES_MAX))
+ return -EINVAL;
+
+ if (memchr_inv(ulr.padding, 0, sizeof(ulr.padding)))
+ return -EINVAL;
+
+ lc = &ulr.config;
+ ret = gpio_v2_line_config_validate(lc, ulr.num_lines);
+ if (ret)
+ return ret;
+
+ lr = kzalloc(struct_size(lr, lines, ulr.num_lines), GFP_KERNEL);
+ if (!lr)
+ return -ENOMEM;
+
+ lr->gdev = gdev;
+ get_device(&gdev->dev);
+
+ for (i = 0; i < ulr.num_lines; i++) {
+ lr->lines[i].req = lr;
+ WRITE_ONCE(lr->lines[i].sw_debounced, 0);
+ INIT_DELAYED_WORK(&lr->lines[i].work, debounce_work_func);
+ }
+
+ if (ulr.consumer[0] != '\0') {
+ /* label is only initialized if consumer is set */
+ lr->label = kstrndup(ulr.consumer, sizeof(ulr.consumer) - 1,
+ GFP_KERNEL);
+ if (!lr->label) {
+ ret = -ENOMEM;
+ goto out_free_linereq;
+ }
+ }
+
+ mutex_init(&lr->config_mutex);
+ init_waitqueue_head(&lr->wait);
+ lr->event_buffer_size = ulr.event_buffer_size;
+ if (lr->event_buffer_size == 0)
+ lr->event_buffer_size = ulr.num_lines * 16;
+ else if (lr->event_buffer_size > GPIO_V2_LINES_MAX * 16)
+ lr->event_buffer_size = GPIO_V2_LINES_MAX * 16;
+
+ atomic_set(&lr->seqno, 0);
+ lr->num_lines = ulr.num_lines;
+
+ /* Request each GPIO */
+ for (i = 0; i < ulr.num_lines; i++) {
+ u32 offset = ulr.offsets[i];
+ struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset);
+
+ if (IS_ERR(desc)) {
+ ret = PTR_ERR(desc);
+ goto out_free_linereq;
+ }
+
+ ret = gpiod_request(desc, lr->label);
+ if (ret)
+ goto out_free_linereq;
+
+ lr->lines[i].desc = desc;
+ flags = gpio_v2_line_config_flags(lc, i);
+ gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags);
+
+ ret = gpiod_set_transitory(desc, false);
+ if (ret < 0)
+ goto out_free_linereq;
+
+ /*
+ * Lines have to be requested explicitly for input
+ * or output, else the line will be treated "as is".
+ */
+ if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
+ int val = gpio_v2_line_config_output_value(lc, i);
+
+ ret = gpiod_direction_output(desc, val);
+ if (ret)
+ goto out_free_linereq;
+ } else if (flags & GPIO_V2_LINE_FLAG_INPUT) {
+ ret = gpiod_direction_input(desc);
+ if (ret)
+ goto out_free_linereq;
+
+ ret = edge_detector_setup(&lr->lines[i], lc, i,
+ flags & GPIO_V2_LINE_EDGE_FLAGS);
+ if (ret)
+ goto out_free_linereq;
+ }
+
+ blocking_notifier_call_chain(&desc->gdev->notifier,
+ GPIO_V2_LINE_CHANGED_REQUESTED, desc);
+
+ dev_dbg(&gdev->dev, "registered chardev handle for line %d\n",
+ offset);
+ }
+
+ fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
+ if (fd < 0) {
+ ret = fd;
+ goto out_free_linereq;
+ }
+
+ file = anon_inode_getfile("gpio-line", &line_fileops, lr,
+ O_RDONLY | O_CLOEXEC);
+ if (IS_ERR(file)) {
+ ret = PTR_ERR(file);
+ goto out_put_unused_fd;
+ }
+
+ ulr.fd = fd;
+ if (copy_to_user(ip, &ulr, sizeof(ulr))) {
+ /*
+ * fput() will trigger the release() callback, so do not go onto
+ * the regular error cleanup path here.
+ */
+ fput(file);
+ put_unused_fd(fd);
+ return -EFAULT;
+ }
+
+ fd_install(fd, file);
+
+ dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n",
+ lr->num_lines);
+
+ return 0;
+
+out_put_unused_fd:
+ put_unused_fd(fd);
+out_free_linereq:
+ linereq_free(lr);
+ return ret;
+}
+
+#ifdef CONFIG_GPIO_CDEV_V1
+
+/*
+ * GPIO line event management
+ */
+
+/**
+ * struct lineevent_state - contains the state of a userspace event
+ * @gdev: the GPIO device the event pertains to
+ * @label: consumer label used to tag descriptors
+ * @desc: the GPIO descriptor held by this event
+ * @eflags: the event flags this line was requested with
+ * @irq: the interrupt that trigger in response to events on this GPIO
+ * @wait: wait queue that handles blocking reads of events
+ * @events: KFIFO for the GPIO events
+ * @timestamp: cache for the timestamp storing it between hardirq
+ * and IRQ thread, used to bring the timestamp close to the actual
+ * event
+ */
+struct lineevent_state {
+ struct gpio_device *gdev;
+ const char *label;
+ struct gpio_desc *desc;
+ u32 eflags;
+ int irq;
+ wait_queue_head_t wait;
+ DECLARE_KFIFO(events, struct gpioevent_data, 16);
+ u64 timestamp;
+};
+
+#define GPIOEVENT_REQUEST_VALID_FLAGS \
+ (GPIOEVENT_REQUEST_RISING_EDGE | \
+ GPIOEVENT_REQUEST_FALLING_EDGE)
+
+static __poll_t lineevent_poll(struct file *file,
+ struct poll_table_struct *wait)
+{
+ struct lineevent_state *le = file->private_data;
+ __poll_t events = 0;
+
+ poll_wait(file, &le->wait, wait);
+
+ if (!kfifo_is_empty_spinlocked_noirqsave(&le->events, &le->wait.lock))
+ events = EPOLLIN | EPOLLRDNORM;
+
+ return events;
+}
+
+static ssize_t lineevent_get_size(void)
+{
+#if defined(CONFIG_X86_64) && !defined(CONFIG_UML)
+ /* i386 has no padding after 'id' */
+ if (in_ia32_syscall()) {
+ struct compat_gpioeevent_data {
+ compat_u64 timestamp;
+ u32 id;
+ };
+
+ return sizeof(struct compat_gpioeevent_data);
+ }
+#endif
+ return sizeof(struct gpioevent_data);
+}
+
+static ssize_t lineevent_read(struct file *file,
+ char __user *buf,
+ size_t count,
+ loff_t *f_ps)
+{
+ struct lineevent_state *le = file->private_data;
+ struct gpioevent_data ge;
+ ssize_t bytes_read = 0;
+ ssize_t ge_size;
+ int ret;
+
+ /*
+ * When compatible system call is being used the struct gpioevent_data,
+ * in case of at least ia32, has different size due to the alignment
+ * differences. Because we have first member 64 bits followed by one of
+ * 32 bits there is no gap between them. The only difference is the
+ * padding at the end of the data structure. Hence, we calculate the
+ * actual sizeof() and pass this as an argument to copy_to_user() to
+ * drop unneeded bytes from the output.
+ */
+ ge_size = lineevent_get_size();
+ if (count < ge_size)
+ return -EINVAL;
+
+ do {
+ spin_lock(&le->wait.lock);
+ if (kfifo_is_empty(&le->events)) {
+ if (bytes_read) {
+ spin_unlock(&le->wait.lock);
+ return bytes_read;
+ }
+
+ if (file->f_flags & O_NONBLOCK) {
+ spin_unlock(&le->wait.lock);
+ return -EAGAIN;
+ }
+
+ ret = wait_event_interruptible_locked(le->wait,
+ !kfifo_is_empty(&le->events));
+ if (ret) {
+ spin_unlock(&le->wait.lock);
+ return ret;
+ }
+ }
+
+ ret = kfifo_out(&le->events, &ge, 1);
+ spin_unlock(&le->wait.lock);
+ 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 (copy_to_user(buf + bytes_read, &ge, ge_size))
+ return -EFAULT;
+ bytes_read += ge_size;
+ } while (count >= bytes_read + ge_size);
+
+ return bytes_read;
+}
+
+static void lineevent_free(struct lineevent_state *le)
+{
+ if (le->irq)
+ free_irq(le->irq, le);
+ if (le->desc)
+ gpiod_free(le->desc);
+ kfree(le->label);
+ put_device(&le->gdev->dev);
+ kfree(le);
+}
+
+static int lineevent_release(struct inode *inode, struct file *file)
+{
+ lineevent_free(file->private_data);
+ return 0;
+}
+
+static long lineevent_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ struct lineevent_state *le = file->private_data;
+ void __user *ip = (void __user *)arg;
+ struct gpiohandle_data ghd;
+
+ /*
+ * We can get the value for an event line but not set it,
+ * because it is input by definition.
+ */
+ if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) {
+ int val;
+
+ memset(&ghd, 0, sizeof(ghd));
+
+ val = gpiod_get_value_cansleep(le->desc);
+ if (val < 0)
+ return val;
+ ghd.values[0] = val;
+
+ if (copy_to_user(ip, &ghd, sizeof(ghd)))
+ return -EFAULT;
+
+ return 0;
+ }
+ return -EINVAL;
+}
+
+#ifdef CONFIG_COMPAT
+static long lineevent_ioctl_compat(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ return lineevent_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
+}
+#endif
+
+static const struct file_operations lineevent_fileops = {
+ .release = lineevent_release,
+ .read = lineevent_read,
+ .poll = lineevent_poll,
+ .owner = THIS_MODULE,
+ .llseek = noop_llseek,
+ .unlocked_ioctl = lineevent_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = lineevent_ioctl_compat,
+#endif
+};
+
+static irqreturn_t lineevent_irq_thread(int irq, void *p)
+{
+ struct lineevent_state *le = p;
+ struct gpioevent_data ge;
+ int ret;
+
+ /* Do not leak kernel stack to userspace */
+ memset(&ge, 0, sizeof(ge));
+
+ /*
+ * We may be running from a nested threaded interrupt in which case
+ * we didn't get the timestamp from lineevent_irq_handler().
+ */
+ if (!le->timestamp)
+ ge.timestamp = ktime_get_ns();
+ else
+ ge.timestamp = le->timestamp;
+
+ if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE
+ && le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
+ int level = gpiod_get_value_cansleep(le->desc);
+
+ if (level)
+ /* Emit low-to-high event */
+ ge.id = GPIOEVENT_EVENT_RISING_EDGE;
+ else
+ /* Emit high-to-low event */
+ ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
+ } else if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE) {
+ /* Emit low-to-high event */
+ ge.id = GPIOEVENT_EVENT_RISING_EDGE;
+ } else if (le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
+ /* Emit high-to-low event */
+ ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
+ } else {
+ return IRQ_NONE;
+ }
+
+ ret = kfifo_in_spinlocked_noirqsave(&le->events, &ge,
+ 1, &le->wait.lock);
+ if (ret)
+ wake_up_poll(&le->wait, EPOLLIN);
+ else
+ pr_debug_ratelimited("event FIFO is full - event dropped\n");
+
+ return IRQ_HANDLED;
+}
+
+static irqreturn_t lineevent_irq_handler(int irq, void *p)
+{
+ struct lineevent_state *le = p;
+
+ /*
+ * Just store the timestamp in hardirq context so we get it as
+ * close in time as possible to the actual event.
+ */
+ le->timestamp = ktime_get_ns();
+
+ return IRQ_WAKE_THREAD;
+}
+
+static int lineevent_create(struct gpio_device *gdev, void __user *ip)
+{
+ struct gpioevent_request eventreq;
+ struct lineevent_state *le;
+ struct gpio_desc *desc;
+ struct file *file;
+ u32 offset;
+ u32 lflags;
+ u32 eflags;
+ int fd;
+ int ret;
+ int irq, irqflags = 0;
+
+ if (copy_from_user(&eventreq, ip, sizeof(eventreq)))
+ return -EFAULT;
+
+ offset = eventreq.lineoffset;
+ lflags = eventreq.handleflags;
+ eflags = eventreq.eventflags;
+
+ desc = gpiochip_get_desc(gdev->chip, offset);
+ if (IS_ERR(desc))
+ return PTR_ERR(desc);
+
+ /* Return an error if a unknown flag is set */
+ if ((lflags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) ||
+ (eflags & ~GPIOEVENT_REQUEST_VALID_FLAGS))
+ return -EINVAL;
+
+ /* This is just wrong: we don't look for events on output lines */
+ if ((lflags & GPIOHANDLE_REQUEST_OUTPUT) ||
+ (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
+ (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE))
+ return -EINVAL;
+
+ /* Only one bias flag can be set. */
+ if (((lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE) &&
+ (lflags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN |
+ GPIOHANDLE_REQUEST_BIAS_PULL_UP))) ||
+ ((lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) &&
+ (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)))
+ return -EINVAL;
+
+ le = kzalloc(sizeof(*le), GFP_KERNEL);
+ if (!le)
+ return -ENOMEM;
+ le->gdev = gdev;
+ get_device(&gdev->dev);
+
+ if (eventreq.consumer_label[0] != '\0') {
+ /* label is only initialized if consumer_label is set */
+ le->label = kstrndup(eventreq.consumer_label,
+ sizeof(eventreq.consumer_label) - 1,
+ GFP_KERNEL);
+ if (!le->label) {
+ ret = -ENOMEM;
+ goto out_free_le;
+ }
+ }
+
+ ret = gpiod_request(desc, le->label);
+ if (ret)
+ goto out_free_le;
+ le->desc = desc;
+ le->eflags = eflags;
+
+ linehandle_flags_to_desc_flags(lflags, &desc->flags);
+
+ ret = gpiod_direction_input(desc);
+ if (ret)
+ goto out_free_le;
+
+ blocking_notifier_call_chain(&desc->gdev->notifier,
+ GPIO_V2_LINE_CHANGED_REQUESTED, desc);
+
+ irq = gpiod_to_irq(desc);
+ if (irq <= 0) {
+ ret = -ENODEV;
+ goto out_free_le;
+ }
+ le->irq = irq;
+
+ if (eflags & GPIOEVENT_REQUEST_RISING_EDGE)
+ irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
+ IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
+ if (eflags & GPIOEVENT_REQUEST_FALLING_EDGE)
+ irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
+ IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
+ irqflags |= IRQF_ONESHOT;
+
+ INIT_KFIFO(le->events);
+ init_waitqueue_head(&le->wait);
+
+ /* Request a thread to read the events */
+ ret = request_threaded_irq(le->irq,
+ lineevent_irq_handler,
+ lineevent_irq_thread,
+ irqflags,
+ le->label,
+ le);
+ if (ret)
+ goto out_free_le;
+
+ fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
+ if (fd < 0) {
+ ret = fd;
+ goto out_free_le;
+ }
+
+ file = anon_inode_getfile("gpio-event",
+ &lineevent_fileops,
+ le,
+ O_RDONLY | O_CLOEXEC);
+ if (IS_ERR(file)) {
+ ret = PTR_ERR(file);
+ goto out_put_unused_fd;
+ }
+
+ eventreq.fd = fd;
+ if (copy_to_user(ip, &eventreq, sizeof(eventreq))) {
+ /*
+ * fput() will trigger the release() callback, so do not go onto
+ * the regular error cleanup path here.
+ */
+ fput(file);
+ put_unused_fd(fd);
+ return -EFAULT;
+ }
+
+ fd_install(fd, file);
+
+ return 0;
+
+out_put_unused_fd:
+ put_unused_fd(fd);
+out_free_le:
+ lineevent_free(le);
+ return ret;
+}
+
+static void gpio_v2_line_info_to_v1(struct gpio_v2_line_info *info_v2,
+ struct gpioline_info *info_v1)
+{
+ u64 flagsv2 = info_v2->flags;
+
+ memcpy(info_v1->name, info_v2->name, sizeof(info_v1->name));
+ memcpy(info_v1->consumer, info_v2->consumer, sizeof(info_v1->consumer));
+ info_v1->line_offset = info_v2->offset;
+ info_v1->flags = 0;
+
+ if (flagsv2 & GPIO_V2_LINE_FLAG_USED)
+ info_v1->flags |= GPIOLINE_FLAG_KERNEL;
+
+ if (flagsv2 & GPIO_V2_LINE_FLAG_OUTPUT)
+ info_v1->flags |= GPIOLINE_FLAG_IS_OUT;
+
+ if (flagsv2 & GPIO_V2_LINE_FLAG_ACTIVE_LOW)
+ info_v1->flags |= GPIOLINE_FLAG_ACTIVE_LOW;
+
+ if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_DRAIN)
+ info_v1->flags |= GPIOLINE_FLAG_OPEN_DRAIN;
+ if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_SOURCE)
+ info_v1->flags |= GPIOLINE_FLAG_OPEN_SOURCE;
+
+ if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_UP)
+ info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_UP;
+ if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN)
+ info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_DOWN;
+ if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_DISABLED)
+ info_v1->flags |= GPIOLINE_FLAG_BIAS_DISABLE;
+}
+
+static void gpio_v2_line_info_changed_to_v1(
+ struct gpio_v2_line_info_changed *lic_v2,
+ struct gpioline_info_changed *lic_v1)
+{
+ memset(lic_v1, 0, sizeof(*lic_v1));
+ gpio_v2_line_info_to_v1(&lic_v2->info, &lic_v1->info);
+ lic_v1->timestamp = lic_v2->timestamp_ns;
+ lic_v1->event_type = lic_v2->event_type;
+}
+
+#endif /* CONFIG_GPIO_CDEV_V1 */
+
+static void gpio_desc_to_lineinfo(struct gpio_desc *desc,
+ struct gpio_v2_line_info *info)
+{
+ struct gpio_chip *gc = desc->gdev->chip;
+ bool ok_for_pinctrl;
+ unsigned long flags;
+ u32 debounce_period_us;
+ unsigned int num_attrs = 0;
+
+ memset(info, 0, sizeof(*info));
+ info->offset = gpio_chip_hwgpio(desc);
+
+ /*
+ * This function takes a mutex so we must check this before taking
+ * the spinlock.
+ *
+ * FIXME: find a non-racy way to retrieve this information. Maybe a
+ * lock common to both frameworks?
+ */
+ ok_for_pinctrl =
+ pinctrl_gpio_can_use_line(gc->base + info->offset);
+
+ spin_lock_irqsave(&gpio_lock, flags);
+
+ if (desc->name)
+ strscpy(info->name, desc->name, sizeof(info->name));
+
+ if (desc->label)
+ strscpy(info->consumer, desc->label, sizeof(info->consumer));
+
+ /*
+ * Userspace only need to know that the kernel is using this GPIO so
+ * it can't use it.
+ */
+ info->flags = 0;
+ if (test_bit(FLAG_REQUESTED, &desc->flags) ||
+ test_bit(FLAG_IS_HOGGED, &desc->flags) ||
+ test_bit(FLAG_USED_AS_IRQ, &desc->flags) ||
+ test_bit(FLAG_EXPORT, &desc->flags) ||
+ test_bit(FLAG_SYSFS, &desc->flags) ||
+ !ok_for_pinctrl)
+ info->flags |= GPIO_V2_LINE_FLAG_USED;
+
+ if (test_bit(FLAG_IS_OUT, &desc->flags))
+ info->flags |= GPIO_V2_LINE_FLAG_OUTPUT;
+ else
+ info->flags |= GPIO_V2_LINE_FLAG_INPUT;
+
+ if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
+ info->flags |= GPIO_V2_LINE_FLAG_ACTIVE_LOW;
+
+ if (test_bit(FLAG_OPEN_DRAIN, &desc->flags))
+ info->flags |= GPIO_V2_LINE_FLAG_OPEN_DRAIN;
+ if (test_bit(FLAG_OPEN_SOURCE, &desc->flags))
+ info->flags |= GPIO_V2_LINE_FLAG_OPEN_SOURCE;
+
+ if (test_bit(FLAG_BIAS_DISABLE, &desc->flags))
+ info->flags |= GPIO_V2_LINE_FLAG_BIAS_DISABLED;
+ if (test_bit(FLAG_PULL_DOWN, &desc->flags))
+ info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN;
+ if (test_bit(FLAG_PULL_UP, &desc->flags))
+ info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_UP;
+
+ if (test_bit(FLAG_EDGE_RISING, &desc->flags))
+ info->flags |= GPIO_V2_LINE_FLAG_EDGE_RISING;
+ if (test_bit(FLAG_EDGE_FALLING, &desc->flags))
+ info->flags |= GPIO_V2_LINE_FLAG_EDGE_FALLING;
+
+ debounce_period_us = READ_ONCE(desc->debounce_period_us);
+ if (debounce_period_us) {
+ info->attrs[num_attrs].id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE;
+ info->attrs[num_attrs].debounce_period_us = debounce_period_us;
+ num_attrs++;
+ }
+ info->num_attrs = num_attrs;
+
+ spin_unlock_irqrestore(&gpio_lock, flags);
+}
+
+struct gpio_chardev_data {
+ struct gpio_device *gdev;
+ wait_queue_head_t wait;
+ DECLARE_KFIFO(events, struct gpio_v2_line_info_changed, 32);
+ struct notifier_block lineinfo_changed_nb;
+ unsigned long *watched_lines;
+#ifdef CONFIG_GPIO_CDEV_V1
+ atomic_t watch_abi_version;
+#endif
+};
+
+static int chipinfo_get(struct gpio_chardev_data *cdev, void __user *ip)
+{
+ struct gpio_device *gdev = cdev->gdev;
+ struct gpiochip_info chipinfo;
+
+ memset(&chipinfo, 0, sizeof(chipinfo));
+
+ strscpy(chipinfo.name, dev_name(&gdev->dev), sizeof(chipinfo.name));
+ strscpy(chipinfo.label, gdev->label, sizeof(chipinfo.label));
+ chipinfo.lines = gdev->ngpio;
+ if (copy_to_user(ip, &chipinfo, sizeof(chipinfo)))
+ return -EFAULT;
+ return 0;
+}
+
+#ifdef CONFIG_GPIO_CDEV_V1
+/*
+ * returns 0 if the versions match, else the previously selected ABI version
+ */
+static int lineinfo_ensure_abi_version(struct gpio_chardev_data *cdata,
+ unsigned int version)
+{
+ int abiv = atomic_cmpxchg(&cdata->watch_abi_version, 0, version);
+
+ if (abiv == version)
+ return 0;
+
+ return abiv;
+}
+
+static int lineinfo_get_v1(struct gpio_chardev_data *cdev, void __user *ip,
+ bool watch)
+{
+ struct gpio_desc *desc;
+ struct gpioline_info lineinfo;
+ struct gpio_v2_line_info lineinfo_v2;
+
+ if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
+ return -EFAULT;
+
+ /* this doubles as a range check on line_offset */
+ desc = gpiochip_get_desc(cdev->gdev->chip, lineinfo.line_offset);
+ if (IS_ERR(desc))
+ return PTR_ERR(desc);
+
+ if (watch) {
+ if (lineinfo_ensure_abi_version(cdev, 1))
+ return -EPERM;
+
+ if (test_and_set_bit(lineinfo.line_offset, cdev->watched_lines))
+ return -EBUSY;
+ }
+
+ gpio_desc_to_lineinfo(desc, &lineinfo_v2);
+ gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo);
+
+ if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
+ if (watch)
+ clear_bit(lineinfo.line_offset, cdev->watched_lines);
+ return -EFAULT;
+ }
+
+ return 0;
+}
+#endif
+
+static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip,
+ bool watch)
+{
+ struct gpio_desc *desc;
+ struct gpio_v2_line_info lineinfo;
+
+ if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
+ return -EFAULT;
+
+ if (memchr_inv(lineinfo.padding, 0, sizeof(lineinfo.padding)))
+ return -EINVAL;
+
+ desc = gpiochip_get_desc(cdev->gdev->chip, lineinfo.offset);
+ if (IS_ERR(desc))
+ return PTR_ERR(desc);
+
+ if (watch) {
+#ifdef CONFIG_GPIO_CDEV_V1
+ if (lineinfo_ensure_abi_version(cdev, 2))
+ return -EPERM;
+#endif
+ if (test_and_set_bit(lineinfo.offset, cdev->watched_lines))
+ return -EBUSY;
+ }
+ gpio_desc_to_lineinfo(desc, &lineinfo);
+
+ if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
+ if (watch)
+ clear_bit(lineinfo.offset, cdev->watched_lines);
+ return -EFAULT;
+ }
+
+ return 0;
+}
+
+static int lineinfo_unwatch(struct gpio_chardev_data *cdev, void __user *ip)
+{
+ __u32 offset;
+
+ if (copy_from_user(&offset, ip, sizeof(offset)))
+ return -EFAULT;
+
+ if (offset >= cdev->gdev->ngpio)
+ return -EINVAL;
+
+ if (!test_and_clear_bit(offset, cdev->watched_lines))
+ return -EBUSY;
+
+ return 0;
+}
+
+/*
+ * gpio_ioctl() - ioctl handler for the GPIO chardev
+ */
+static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ struct gpio_chardev_data *cdev = file->private_data;
+ struct gpio_device *gdev = cdev->gdev;
+ void __user *ip = (void __user *)arg;
+
+ /* We fail any subsequent ioctl():s when the chip is gone */
+ if (!gdev->chip)
+ return -ENODEV;
+
+ /* Fill in the struct and pass to userspace */
+ if (cmd == GPIO_GET_CHIPINFO_IOCTL) {
+ return chipinfo_get(cdev, ip);
+#ifdef CONFIG_GPIO_CDEV_V1
+ } else if (cmd == GPIO_GET_LINEHANDLE_IOCTL) {
+ return linehandle_create(gdev, ip);
+ } else if (cmd == GPIO_GET_LINEEVENT_IOCTL) {
+ return lineevent_create(gdev, ip);
+ } else if (cmd == GPIO_GET_LINEINFO_IOCTL ||
+ cmd == GPIO_GET_LINEINFO_WATCH_IOCTL) {
+ return lineinfo_get_v1(cdev, ip,
+ cmd == GPIO_GET_LINEINFO_WATCH_IOCTL);
+#endif /* CONFIG_GPIO_CDEV_V1 */
+ } else if (cmd == GPIO_V2_GET_LINEINFO_IOCTL ||
+ cmd == GPIO_V2_GET_LINEINFO_WATCH_IOCTL) {
+ return lineinfo_get(cdev, ip,
+ cmd == GPIO_V2_GET_LINEINFO_WATCH_IOCTL);
+ } else if (cmd == GPIO_V2_GET_LINE_IOCTL) {
+ return linereq_create(gdev, ip);
+ } else if (cmd == GPIO_GET_LINEINFO_UNWATCH_IOCTL) {
+ return lineinfo_unwatch(cdev, ip);
+ }
+ return -EINVAL;
+}
+
+#ifdef CONFIG_COMPAT
+static long gpio_ioctl_compat(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ return gpio_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
+}
+#endif
+
+static struct gpio_chardev_data *
+to_gpio_chardev_data(struct notifier_block *nb)
+{
+ return container_of(nb, struct gpio_chardev_data, lineinfo_changed_nb);
+}
+
+static int lineinfo_changed_notify(struct notifier_block *nb,
+ unsigned long action, void *data)
+{
+ struct gpio_chardev_data *cdev = to_gpio_chardev_data(nb);
+ struct gpio_v2_line_info_changed chg;
+ 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);
+
+ 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");
+
+ return NOTIFY_OK;
+}
+
+static __poll_t lineinfo_watch_poll(struct file *file,
+ struct poll_table_struct *pollt)
+{
+ struct gpio_chardev_data *cdev = file->private_data;
+ __poll_t events = 0;
+
+ poll_wait(file, &cdev->wait, pollt);
+
+ if (!kfifo_is_empty_spinlocked_noirqsave(&cdev->events,
+ &cdev->wait.lock))
+ events = EPOLLIN | EPOLLRDNORM;
+
+ return events;
+}
+
+static ssize_t lineinfo_watch_read(struct file *file, char __user *buf,
+ size_t count, loff_t *off)
+{
+ struct gpio_chardev_data *cdev = file->private_data;
+ struct gpio_v2_line_info_changed event;
+ ssize_t bytes_read = 0;
+ int ret;
+ size_t event_size;
+
+#ifndef CONFIG_GPIO_CDEV_V1
+ event_size = sizeof(struct gpio_v2_line_info_changed);
+ if (count < event_size)
+ return -EINVAL;
+#endif
+
+ do {
+ spin_lock(&cdev->wait.lock);
+ if (kfifo_is_empty(&cdev->events)) {
+ if (bytes_read) {
+ spin_unlock(&cdev->wait.lock);
+ return bytes_read;
+ }
+
+ if (file->f_flags & O_NONBLOCK) {
+ spin_unlock(&cdev->wait.lock);
+ return -EAGAIN;
+ }
+
+ ret = wait_event_interruptible_locked(cdev->wait,
+ !kfifo_is_empty(&cdev->events));
+ if (ret) {
+ spin_unlock(&cdev->wait.lock);
+ return ret;
+ }
+ }
+#ifdef CONFIG_GPIO_CDEV_V1
+ /* must be after kfifo check so watch_abi_version is set */
+ if (atomic_read(&cdev->watch_abi_version) == 2)
+ event_size = sizeof(struct gpio_v2_line_info_changed);
+ else
+ event_size = sizeof(struct gpioline_info_changed);
+ if (count < event_size) {
+ spin_unlock(&cdev->wait.lock);
+ return -EINVAL;
+ }
+#endif
+ ret = kfifo_out(&cdev->events, &event, 1);
+ spin_unlock(&cdev->wait.lock);
+ if (ret != 1) {
+ ret = -EIO;
+ break;
+ /* We should never get here. See lineevent_read(). */
+ }
+
+#ifdef CONFIG_GPIO_CDEV_V1
+ if (event_size == sizeof(struct gpio_v2_line_info_changed)) {
+ if (copy_to_user(buf + bytes_read, &event, event_size))
+ return -EFAULT;
+ } else {
+ struct gpioline_info_changed event_v1;
+
+ gpio_v2_line_info_changed_to_v1(&event, &event_v1);
+ if (copy_to_user(buf + bytes_read, &event_v1,
+ event_size))
+ return -EFAULT;
+ }
+#else
+ if (copy_to_user(buf + bytes_read, &event, event_size))
+ return -EFAULT;
+#endif
+ bytes_read += event_size;
+ } while (count >= bytes_read + sizeof(event));
+
+ return bytes_read;
+}
+
+/**
+ * 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
+ */
+static int gpio_chrdev_open(struct inode *inode, struct file *file)
+{
+ struct gpio_device *gdev = container_of(inode->i_cdev,
+ struct gpio_device, chrdev);
+ struct gpio_chardev_data *cdev;
+ int ret = -ENOMEM;
+
+ /* Fail on open if the backing gpiochip is gone */
+ if (!gdev->chip)
+ return -ENODEV;
+
+ cdev = kzalloc(sizeof(*cdev), GFP_KERNEL);
+ if (!cdev)
+ return -ENOMEM;
+
+ cdev->watched_lines = bitmap_zalloc(gdev->chip->ngpio, GFP_KERNEL);
+ if (!cdev->watched_lines)
+ goto out_free_cdev;
+
+ init_waitqueue_head(&cdev->wait);
+ INIT_KFIFO(cdev->events);
+ cdev->gdev = gdev;
+
+ cdev->lineinfo_changed_nb.notifier_call = lineinfo_changed_notify;
+ ret = blocking_notifier_chain_register(&gdev->notifier,
+ &cdev->lineinfo_changed_nb);
+ if (ret)
+ goto out_free_bitmap;
+
+ get_device(&gdev->dev);
+ file->private_data = cdev;
+
+ ret = nonseekable_open(inode, file);
+ if (ret)
+ goto out_unregister_notifier;
+
+ return ret;
+
+out_unregister_notifier:
+ blocking_notifier_chain_unregister(&gdev->notifier,
+ &cdev->lineinfo_changed_nb);
+out_free_bitmap:
+ bitmap_free(cdev->watched_lines);
+out_free_cdev:
+ kfree(cdev);
+ return ret;
+}
+
+/**
+ * gpio_chrdev_release() - close chardev after ioctl operations
+ * @inode: inode for this chardev
+ * @file: file struct for storing private data
+ * Returns 0 on success
+ */
+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->notifier,
+ &cdev->lineinfo_changed_nb);
+ put_device(&gdev->dev);
+ kfree(cdev);
+
+ return 0;
+}
+
+static const struct file_operations gpio_fileops = {
+ .release = gpio_chrdev_release,
+ .open = gpio_chrdev_open,
+ .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,
+#endif
+};
+
+int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt)
+{
+ int ret;
+
+ cdev_init(&gdev->chrdev, &gpio_fileops);
+ gdev->chrdev.owner = THIS_MODULE;
+ gdev->dev.devt = MKDEV(MAJOR(devt), gdev->id);
+
+ ret = cdev_device_add(&gdev->chrdev, &gdev->dev);
+ if (ret)
+ return ret;
+
+ chip_dbg(gdev->chip, "added GPIO chardev (%d:%d)\n",
+ MAJOR(devt), gdev->id);
+
+ return 0;
+}
+
+void gpiolib_cdev_unregister(struct gpio_device *gdev)
+{
+ cdev_device_del(&gdev->chrdev, &gdev->dev);
+}