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linux/drivers/gpio/gpiolib-cdev.c
Andy Shevchenko e106b1dd38 gpiolib: cdev: use !mem_is_zero() instead of memchr_inv(s, 0, n) 
Use the mem_is_zero() helper where possible.

Signed-off-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20241110201706.16614-1-andy.shevchenko@gmail.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
2024-11-12 09:46:17 +01:00

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// 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/cleanup.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/hte.h>
#include <linux/interrupt.h>
#include <linux/irqreturn.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/seq_file.h>
#include <linux/spinlock.h>
#include <linux/string.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)
#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 */
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)
{
unsigned long flags = READ_ONCE(*flagsp);
assign_bit(FLAG_ACTIVE_LOW, &flags,
lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW);
assign_bit(FLAG_OPEN_DRAIN, &flags,
lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN);
assign_bit(FLAG_OPEN_SOURCE, &flags,
lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE);
assign_bit(FLAG_PULL_UP, &flags,
lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP);
assign_bit(FLAG_PULL_DOWN, &flags,
lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN);
assign_bit(FLAG_BIAS_DISABLE, &flags,
lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE);
WRITE_ONCE(*flagsp, flags);
}
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;
/* 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(lflags, &desc->flags);
if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {
int val = !!gcnf.default_values[i];
ret = gpiod_direction_output_nonotify(desc, val);
if (ret)
return ret;
} else {
ret = gpiod_direction_input_nonotify(desc);
if (ret)
return ret;
}
gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_CONFIG);
}
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);
unsigned int i;
int ret;
guard(srcu)(&lh->gdev->srcu);
if (!rcu_access_pointer(lh->gdev->chip))
return -ENODEV;
switch (cmd) {
case GPIOHANDLE_GET_LINE_VALUES_IOCTL:
/* NOTE: It's okay to read values of output lines */
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;
case 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);
case GPIOHANDLE_SET_CONFIG_IOCTL:
return linehandle_set_config(lh, ip);
default:
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);
gpio_device_put(lh->gdev);
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 = gpio_device_get(gdev);
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 = gpio_device_get_desc(gdev, offset);
if (IS_ERR(desc)) {
ret = PTR_ERR(desc);
goto out_free_lh;
}
ret = gpiod_request_user(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_nonotify(desc, val);
if (ret)
goto out_free_lh;
} else if (lflags & GPIOHANDLE_REQUEST_INPUT) {
ret = gpiod_direction_input_nonotify(desc);
if (ret)
goto out_free_lh;
}
gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED);
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
* @edflags: 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
* @hdesc: the Hardware Timestamp Engine (HTE) descriptor
* @raw_level: the line level at the time of event
* @total_discard_seq: the running counter of the discarded events
* @last_seqno: the last sequence number before debounce period expires
*/
struct line {
struct gpio_desc *desc;
/*
* -- edge detector specific fields --
*/
struct linereq *req;
unsigned int irq;
/*
* The flags for the active edge detector configuration.
*
* edflags is set by linereq_create(), linereq_free(), and
* 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.
*/
u64 edflags;
/*
* 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;
#ifdef CONFIG_HTE
struct hte_ts_desc hdesc;
/*
* HTE provider sets line level at the time of event. The valid
* value is 0 or 1 and negative value for an error.
*/
int raw_level;
/*
* when sw_debounce is set on HTE enabled line, this is running
* counter of the discarded events.
*/
u32 total_discard_seq;
/*
* when sw_debounce is set on HTE enabled line, this variable records
* last sequence number before debounce period expires.
*/
u32 last_seqno;
#endif /* CONFIG_HTE */
};
/**
* 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
* @device_unregistered_nb: notifier block for receiving gdev unregister 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;
struct notifier_block device_unregistered_nb;
u32 event_buffer_size;
DECLARE_KFIFO_PTR(events, struct gpio_v2_line_event);
atomic_t seqno;
struct mutex config_mutex;
struct line lines[] __counted_by(num_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_FLAG_EDGE_BOTH GPIO_V2_LINE_EDGE_FLAGS
#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_FLAG_EVENT_CLOCK_REALTIME | \
GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE | \
GPIO_V2_LINE_BIAS_FLAGS)
/* subset of flags relevant for edge detector configuration */
#define GPIO_V2_LINE_EDGE_DETECTOR_FLAGS \
(GPIO_V2_LINE_FLAG_ACTIVE_LOW | \
GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE | \
GPIO_V2_LINE_EDGE_FLAGS)
static int linereq_unregistered_notify(struct notifier_block *nb,
unsigned long action, void *data)
{
struct linereq *lr = container_of(nb, struct linereq,
device_unregistered_nb);
wake_up_poll(&lr->wait, EPOLLIN | EPOLLERR);
return NOTIFY_OK;
}
static void linereq_put_event(struct linereq *lr,
struct gpio_v2_line_event *le)
{
bool overflow = false;
scoped_guard(spinlock, &lr->wait.lock) {
if (kfifo_is_full(&lr->events)) {
overflow = true;
kfifo_skip(&lr->events);
}
kfifo_in(&lr->events, le, 1);
}
if (!overflow)
wake_up_poll(&lr->wait, EPOLLIN);
else
pr_debug_ratelimited("event FIFO is full - event dropped\n");
}
static u64 line_event_timestamp(struct line *line)
{
if (test_bit(FLAG_EVENT_CLOCK_REALTIME, &line->desc->flags))
return ktime_get_real_ns();
else if (IS_ENABLED(CONFIG_HTE) &&
test_bit(FLAG_EVENT_CLOCK_HTE, &line->desc->flags))
return line->timestamp_ns;
return ktime_get_ns();
}
static u32 line_event_id(int level)
{
return level ? GPIO_V2_LINE_EVENT_RISING_EDGE :
GPIO_V2_LINE_EVENT_FALLING_EDGE;
}
static inline char *make_irq_label(const char *orig)
{
char *new;
if (!orig)
return NULL;
new = kstrdup_and_replace(orig, '/', ':', GFP_KERNEL);
if (!new)
return ERR_PTR(-ENOMEM);
return new;
}
static inline void free_irq_label(const char *label)
{
kfree(label);
}
#ifdef CONFIG_HTE
static enum hte_return process_hw_ts_thread(void *p)
{
struct line *line;
struct linereq *lr;
struct gpio_v2_line_event le;
u64 edflags;
int level;
if (!p)
return HTE_CB_HANDLED;
line = p;
lr = line->req;
memset(&le, 0, sizeof(le));
le.timestamp_ns = line->timestamp_ns;
edflags = READ_ONCE(line->edflags);
switch (edflags & GPIO_V2_LINE_EDGE_FLAGS) {
case GPIO_V2_LINE_FLAG_EDGE_BOTH:
level = (line->raw_level >= 0) ?
line->raw_level :
gpiod_get_raw_value_cansleep(line->desc);
if (edflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW)
level = !level;
le.id = line_event_id(level);
break;
case GPIO_V2_LINE_FLAG_EDGE_RISING:
le.id = GPIO_V2_LINE_EVENT_RISING_EDGE;
break;
case GPIO_V2_LINE_FLAG_EDGE_FALLING:
le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE;
break;
default:
return HTE_CB_HANDLED;
}
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 HTE_CB_HANDLED;
}
static enum hte_return process_hw_ts(struct hte_ts_data *ts, void *p)
{
struct line *line;
struct linereq *lr;
int diff_seqno = 0;
if (!ts || !p)
return HTE_CB_HANDLED;
line = p;
line->timestamp_ns = ts->tsc;
line->raw_level = ts->raw_level;
lr = line->req;
if (READ_ONCE(line->sw_debounced)) {
line->total_discard_seq++;
line->last_seqno = ts->seq;
mod_delayed_work(system_wq, &line->work,
usecs_to_jiffies(READ_ONCE(line->desc->debounce_period_us)));
} else {
if (unlikely(ts->seq < line->line_seqno))
return HTE_CB_HANDLED;
diff_seqno = ts->seq - line->line_seqno;
line->line_seqno = ts->seq;
if (lr->num_lines != 1)
line->req_seqno = atomic_add_return(diff_seqno,
&lr->seqno);
return HTE_RUN_SECOND_CB;
}
return HTE_CB_HANDLED;
}
static int hte_edge_setup(struct line *line, u64 eflags)
{
int ret;
unsigned long flags = 0;
struct hte_ts_desc *hdesc = &line->hdesc;
if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING)
flags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
HTE_FALLING_EDGE_TS :
HTE_RISING_EDGE_TS;
if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING)
flags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
HTE_RISING_EDGE_TS :
HTE_FALLING_EDGE_TS;
line->total_discard_seq = 0;
hte_init_line_attr(hdesc, desc_to_gpio(line->desc), flags, NULL,
line->desc);
ret = hte_ts_get(NULL, hdesc, 0);
if (ret)
return ret;
return hte_request_ts_ns(hdesc, process_hw_ts, process_hw_ts_thread,
line);
}
#else
static int hte_edge_setup(struct line *line, u64 eflags)
{
return 0;
}
#endif /* CONFIG_HTE */
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 = line_event_timestamp(line);
if (lr->num_lines != 1)
line->req_seqno = atomic_inc_return(&lr->seqno);
}
line->timestamp_ns = 0;
switch (READ_ONCE(line->edflags) & GPIO_V2_LINE_EDGE_FLAGS) {
case GPIO_V2_LINE_FLAG_EDGE_BOTH:
le.id = line_event_id(gpiod_get_value_cansleep(line->desc));
break;
case GPIO_V2_LINE_FLAG_EDGE_RISING:
le.id = GPIO_V2_LINE_EVENT_RISING_EDGE;
break;
case GPIO_V2_LINE_FLAG_EDGE_FALLING:
le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE;
break;
default:
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 = line_event_timestamp(line);
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;
u64 eflags, edflags = READ_ONCE(line->edflags);
int level = -1;
#ifdef CONFIG_HTE
int diff_seqno;
if (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)
level = line->raw_level;
#endif
if (level < 0)
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 -- */
eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS;
if (!eflags)
return;
/* switch from physical level to logical - if they differ */
if (edflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW)
level = !level;
/* ignore edges that are not being monitored */
if (((eflags == GPIO_V2_LINE_FLAG_EDGE_RISING) && !level) ||
((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 = line_event_timestamp(line);
le.offset = gpio_chip_hwgpio(line->desc);
#ifdef CONFIG_HTE
if (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) {
/* discard events except the last one */
line->total_discard_seq -= 1;
diff_seqno = line->last_seqno - line->total_discard_seq -
line->line_seqno;
line->line_seqno = line->last_seqno - line->total_discard_seq;
le.line_seqno = line->line_seqno;
le.seqno = (lr->num_lines == 1) ?
le.line_seqno : atomic_add_return(diff_seqno, &lr->seqno);
} else
#endif /* CONFIG_HTE */
{
line->line_seqno++;
le.line_seqno = line->line_seqno;
le.seqno = (lr->num_lines == 1) ?
le.line_seqno : atomic_inc_return(&lr->seqno);
}
le.id = line_event_id(level);
linereq_put_event(lr, &le);
}
static int debounce_setup(struct line *line, unsigned int debounce_period_us)
{
unsigned long irqflags;
int ret, level, irq;
char *label;
/*
* 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;
if (debounce_period_us) {
/* setup software debounce */
level = gpiod_get_raw_value_cansleep(line->desc);
if (level < 0)
return level;
if (!(IS_ENABLED(CONFIG_HTE) &&
test_bit(FLAG_EVENT_CLOCK_HTE, &line->desc->flags))) {
irq = gpiod_to_irq(line->desc);
if (irq < 0)
return -ENXIO;
label = make_irq_label(line->req->label);
if (IS_ERR(label))
return -ENOMEM;
irqflags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING;
ret = request_irq(irq, debounce_irq_handler, irqflags,
label, line);
if (ret) {
free_irq_label(label);
return ret;
}
line->irq = irq;
} else {
ret = hte_edge_setup(line, GPIO_V2_LINE_FLAG_EDGE_BOTH);
if (ret)
return ret;
}
WRITE_ONCE(line->level, level);
WRITE_ONCE(line->sw_debounced, 1);
}
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_label(free_irq(line->irq, line));
line->irq = 0;
}
#ifdef CONFIG_HTE
if (READ_ONCE(line->edflags) & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)
hte_ts_put(&line->hdesc);
#endif
cancel_delayed_work_sync(&line->work);
WRITE_ONCE(line->sw_debounced, 0);
WRITE_ONCE(line->edflags, 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)
{
u32 debounce_period_us;
unsigned long irqflags = 0;
u64 eflags;
int irq, ret;
char *label;
eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS;
if (eflags) {
ret = edge_detector_fifo_init(line->req);
if (ret)
return ret;
}
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;
if (IS_ENABLED(CONFIG_HTE) &&
(edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE))
return hte_edge_setup(line, edflags);
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;
label = make_irq_label(line->req->label);
if (IS_ERR(label))
return PTR_ERR(label);
/* Request a thread to read the events */
ret = request_threaded_irq(irq, edge_irq_handler, edge_irq_thread,
irqflags, label, line);
if (ret) {
free_irq_label(label);
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 edflags)
{
u64 active_edflags = READ_ONCE(line->edflags);
unsigned int debounce_period_us =
gpio_v2_line_config_debounce_period(lc, line_idx);
if ((active_edflags == edflags) &&
(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)) {
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;
}
/* reconfiguring edge detection or sw debounce being disabled */
if ((line->irq && !READ_ONCE(line->sw_debounced)) ||
(active_edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) ||
(!debounce_period_us && READ_ONCE(line->sw_debounced)))
edge_detector_stop(line);
return edge_detector_setup(line, lc, line_idx, edflags);
}
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;
if (!IS_ENABLED(CONFIG_HTE) &&
(flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE))
return -EOPNOTSUPP;
/*
* 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;
/* Only allow one event clock source */
if (IS_ENABLED(CONFIG_HTE) &&
(flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME) &&
(flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE))
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 (!mem_is_zero(lc->padding, 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 lflags,
unsigned long *flagsp)
{
unsigned long flags = READ_ONCE(*flagsp);
assign_bit(FLAG_ACTIVE_LOW, &flags,
lflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW);
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, &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, &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, &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, &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)
{
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;
/*
* gpiod_get_array_value_complex() requires compacted desc and val
* arrays, rather than the sparse ones in lv.
* Calculation of num_get and construction of the desc array is
* optimized to avoid allocation for the desc array for the common
* num_get == 1 case.
*/
/* scan requested lines to calculate the subset to get */
for (num_get = 0, i = 0; i < lr->num_lines; i++) {
if (lv.mask & BIT_ULL(i)) {
num_get++;
/* capture desc for the num_get == 1 case */
descs = &lr->lines[i].desc;
}
}
if (num_get == 0)
return -EINVAL;
if (num_get != 1) {
/* build compacted desc array */
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++) {
/* unpack compacted vals for the response */
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(struct linereq *lr, void __user *ip)
{
DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX);
struct gpio_v2_line_values lv;
struct gpio_desc **descs;
unsigned int i, didx, num_set;
int ret;
if (copy_from_user(&lv, ip, sizeof(lv)))
return -EFAULT;
guard(mutex)(&lr->config_mutex);
/*
* gpiod_set_array_value_complex() requires compacted desc and val
* arrays, rather than the sparse ones in lv.
* Calculation of num_set and construction of the descs and vals arrays
* is optimized to minimize scanning the lv->mask, and to avoid
* allocation for the desc array for the common num_set == 1 case.
*/
bitmap_zero(vals, GPIO_V2_LINES_MAX);
/* 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);
num_set++;
/* capture desc for the num_set == 1 case */
descs = &lr->lines[i].desc;
}
}
if (num_set == 0)
return -EINVAL;
if (num_set != 1) {
/* build compacted desc array */
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_config(struct linereq *lr, void __user *ip)
{
struct gpio_v2_line_config lc;
struct gpio_desc *desc;
struct line *line;
unsigned int i;
u64 flags, edflags;
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;
guard(mutex)(&lr->config_mutex);
for (i = 0; i < lr->num_lines; i++) {
line = &lr->lines[i];
desc = lr->lines[i].desc;
flags = gpio_v2_line_config_flags(&lc, i);
/*
* 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_nonotify(desc, val);
if (ret)
return ret;
} else {
ret = gpiod_direction_input_nonotify(desc);
if (ret)
return ret;
ret = edge_detector_update(line, &lc, i, edflags);
if (ret)
return ret;
}
WRITE_ONCE(line->edflags, edflags);
gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_CONFIG);
}
return 0;
}
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;
guard(srcu)(&lr->gdev->srcu);
if (!rcu_access_pointer(lr->gdev->chip))
return -ENODEV;
switch (cmd) {
case GPIO_V2_LINE_GET_VALUES_IOCTL:
return linereq_get_values(lr, ip);
case GPIO_V2_LINE_SET_VALUES_IOCTL:
return linereq_set_values(lr, ip);
case GPIO_V2_LINE_SET_CONFIG_IOCTL:
return linereq_set_config(lr, ip);
default:
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;
guard(srcu)(&lr->gdev->srcu);
if (!rcu_access_pointer(lr->gdev->chip))
return EPOLLHUP | EPOLLERR;
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;
guard(srcu)(&lr->gdev->srcu);
if (!rcu_access_pointer(lr->gdev->chip))
return -ENODEV;
if (count < sizeof(le))
return -EINVAL;
do {
scoped_guard(spinlock, &lr->wait.lock) {
if (kfifo_is_empty(&lr->events)) {
if (bytes_read)
return bytes_read;
if (file->f_flags & O_NONBLOCK)
return -EAGAIN;
ret = wait_event_interruptible_locked(lr->wait,
!kfifo_is_empty(&lr->events));
if (ret)
return ret;
}
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)))
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;
if (lr->device_unregistered_nb.notifier_call)
blocking_notifier_chain_unregister(&lr->gdev->device_notifier,
&lr->device_unregistered_nb);
for (i = 0; i < lr->num_lines; i++) {
if (lr->lines[i].desc) {
edge_detector_stop(&lr->lines[i]);
gpiod_free(lr->lines[i].desc);
}
}
kfifo_free(&lr->events);
kfree(lr->label);
gpio_device_put(lr->gdev);
kvfree(lr);
}
static int linereq_release(struct inode *inode, struct file *file)
{
struct linereq *lr = file->private_data;
linereq_free(lr);
return 0;
}
#ifdef CONFIG_PROC_FS
static void linereq_show_fdinfo(struct seq_file *out, struct file *file)
{
struct linereq *lr = file->private_data;
struct device *dev = &lr->gdev->dev;
u16 i;
seq_printf(out, "gpio-chip:\t%s\n", dev_name(dev));
for (i = 0; i < lr->num_lines; i++)
seq_printf(out, "gpio-line:\t%d\n",
gpio_chip_hwgpio(lr->lines[i].desc));
}
#endif
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
#ifdef CONFIG_PROC_FS
.show_fdinfo = linereq_show_fdinfo,
#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, edflags;
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 (!mem_is_zero(ulr.padding, sizeof(ulr.padding)))
return -EINVAL;
lc = &ulr.config;
ret = gpio_v2_line_config_validate(lc, ulr.num_lines);
if (ret)
return ret;
lr = kvzalloc(struct_size(lr, lines, ulr.num_lines), GFP_KERNEL);
if (!lr)
return -ENOMEM;
lr->num_lines = ulr.num_lines;
lr->gdev = gpio_device_get(gdev);
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);
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;
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);
/* Request each GPIO */
for (i = 0; i < ulr.num_lines; i++) {
u32 offset = ulr.offsets[i];
struct gpio_desc *desc = gpio_device_get_desc(gdev, offset);
if (IS_ERR(desc)) {
ret = PTR_ERR(desc);
goto out_free_linereq;
}
ret = gpiod_request_user(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;
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".
*/
if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
int val = gpio_v2_line_config_output_value(lc, i);
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_nonotify(desc);
if (ret)
goto out_free_linereq;
ret = edge_detector_setup(&lr->lines[i], lc, i,
edflags);
if (ret)
goto out_free_linereq;
}
lr->lines[i].edflags = edflags;
gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED);
dev_dbg(&gdev->dev, "registered chardev handle for line %d\n",
offset);
}
lr->device_unregistered_nb.notifier_call = linereq_unregistered_notify;
ret = blocking_notifier_chain_register(&gdev->device_notifier,
&lr->device_unregistered_nb);
if (ret)
goto out_free_linereq;
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
* @device_unregistered_nb: notifier block for receiving gdev unregister 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;
struct notifier_block device_unregistered_nb;
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;
guard(srcu)(&le->gdev->srcu);
if (!rcu_access_pointer(le->gdev->chip))
return EPOLLHUP | EPOLLERR;
poll_wait(file, &le->wait, wait);
if (!kfifo_is_empty_spinlocked_noirqsave(&le->events, &le->wait.lock))
events = EPOLLIN | EPOLLRDNORM;
return events;
}
static int lineevent_unregistered_notify(struct notifier_block *nb,
unsigned long action, void *data)
{
struct lineevent_state *le = container_of(nb, struct lineevent_state,
device_unregistered_nb);
wake_up_poll(&le->wait, EPOLLIN | EPOLLERR);
return NOTIFY_OK;
}
struct compat_gpioeevent_data {
compat_u64 timestamp;
u32 id;
};
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;
guard(srcu)(&le->gdev->srcu);
if (!rcu_access_pointer(le->gdev->chip))
return -ENODEV;
/*
* 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.
*/
if (compat_need_64bit_alignment_fixup())
ge_size = sizeof(struct compat_gpioeevent_data);
else
ge_size = sizeof(struct gpioevent_data);
if (count < ge_size)
return -EINVAL;
do {
scoped_guard(spinlock, &le->wait.lock) {
if (kfifo_is_empty(&le->events)) {
if (bytes_read)
return bytes_read;
if (file->f_flags & O_NONBLOCK)
return -EAGAIN;
ret = wait_event_interruptible_locked(le->wait,
!kfifo_is_empty(&le->events));
if (ret)
return ret;
}
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))
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->device_unregistered_nb.notifier_call)
blocking_notifier_chain_unregister(&le->gdev->device_notifier,
&le->device_unregistered_nb);
if (le->irq)
free_irq_label(free_irq(le->irq, le));
if (le->desc)
gpiod_free(le->desc);
kfree(le->label);
gpio_device_put(le->gdev);
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;
guard(srcu)(&le->gdev->srcu);
if (!rcu_access_pointer(le->gdev->chip))
return -ENODEV;
/*
* 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;
char *label;
if (copy_from_user(&eventreq, ip, sizeof(eventreq)))
return -EFAULT;
offset = eventreq.lineoffset;
lflags = eventreq.handleflags;
eflags = eventreq.eventflags;
desc = gpio_device_get_desc(gdev, 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 = gpio_device_get(gdev);
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_user(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;
gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED);
irq = gpiod_to_irq(desc);
if (irq <= 0) {
ret = -ENODEV;
goto out_free_le;
}
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);
le->device_unregistered_nb.notifier_call = lineevent_unregistered_notify;
ret = blocking_notifier_chain_register(&gdev->device_notifier,
&le->device_unregistered_nb);
if (ret)
goto out_free_le;
label = make_irq_label(le->label);
if (IS_ERR(label)) {
ret = PTR_ERR(label);
goto out_free_le;
}
/* Request a thread to read the events */
ret = request_threaded_irq(irq,
lineevent_irq_handler,
lineevent_irq_thread,
irqflags,
label,
le);
if (ret) {
free_irq_label(label);
goto out_free_le;
}
le->irq = irq;
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, bool atomic)
{
u32 debounce_period_us;
unsigned long dflags;
const char *label;
CLASS(gpio_chip_guard, guard)(desc);
if (!guard.gc)
return;
memset(info, 0, sizeof(*info));
info->offset = gpio_chip_hwgpio(desc);
if (desc->name)
strscpy(info->name, desc->name, sizeof(info->name));
dflags = READ_ONCE(desc->flags);
scoped_guard(srcu, &desc->gdev->desc_srcu) {
label = gpiod_get_label(desc);
if (label && test_bit(FLAG_REQUESTED, &dflags))
strscpy(info->consumer, label,
sizeof(info->consumer));
}
/*
* Userspace only need know that the kernel is using this GPIO so it
* can't use it.
* The calculation of the used flag is slightly racy, as it may read
* desc, gc and pinctrl state without a lock covering all three at
* once. Worst case if the line is in transition and the calculation
* is inconsistent then it looks to the user like they performed the
* read on the other side of the transition - but that can always
* happen.
* The definitive test that a line is available to userspace is to
* request it.
*/
if (test_bit(FLAG_REQUESTED, &dflags) ||
test_bit(FLAG_IS_HOGGED, &dflags) ||
test_bit(FLAG_EXPORT, &dflags) ||
test_bit(FLAG_SYSFS, &dflags) ||
!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;
else
info->flags |= GPIO_V2_LINE_FLAG_INPUT;
if (test_bit(FLAG_ACTIVE_LOW, &dflags))
info->flags |= GPIO_V2_LINE_FLAG_ACTIVE_LOW;
if (test_bit(FLAG_OPEN_DRAIN, &dflags))
info->flags |= GPIO_V2_LINE_FLAG_OPEN_DRAIN;
if (test_bit(FLAG_OPEN_SOURCE, &dflags))
info->flags |= GPIO_V2_LINE_FLAG_OPEN_SOURCE;
if (test_bit(FLAG_BIAS_DISABLE, &dflags))
info->flags |= GPIO_V2_LINE_FLAG_BIAS_DISABLED;
if (test_bit(FLAG_PULL_DOWN, &dflags))
info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN;
if (test_bit(FLAG_PULL_UP, &dflags))
info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_UP;
if (test_bit(FLAG_EDGE_RISING, &dflags))
info->flags |= GPIO_V2_LINE_FLAG_EDGE_RISING;
if (test_bit(FLAG_EDGE_FALLING, &dflags))
info->flags |= GPIO_V2_LINE_FLAG_EDGE_FALLING;
if (test_bit(FLAG_EVENT_CLOCK_REALTIME, &dflags))
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 {
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;
struct notifier_block device_unregistered_nb;
unsigned long *watched_lines;
#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)
{
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 = gpio_device_get_desc(cdev->gdev, 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, false);
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 (!mem_is_zero(lineinfo.padding, sizeof(lineinfo.padding)))
return -EINVAL;
desc = gpio_device_get_desc(cdev->gdev, 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, false);
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;
guard(srcu)(&gdev->srcu);
/* We fail any subsequent ioctl():s when the chip is gone */
if (!rcu_access_pointer(gdev->chip))
return -ENODEV;
/* Fill in the struct and pass to userspace */
switch (cmd) {
case GPIO_GET_CHIPINFO_IOCTL:
return chipinfo_get(cdev, ip);
#ifdef CONFIG_GPIO_CDEV_V1
case GPIO_GET_LINEHANDLE_IOCTL:
return linehandle_create(gdev, ip);
case GPIO_GET_LINEEVENT_IOCTL:
return lineevent_create(gdev, ip);
case GPIO_GET_LINEINFO_IOCTL:
return lineinfo_get_v1(cdev, ip, false);
case GPIO_GET_LINEINFO_WATCH_IOCTL:
return lineinfo_get_v1(cdev, ip, true);
#endif /* CONFIG_GPIO_CDEV_V1 */
case GPIO_V2_GET_LINEINFO_IOCTL:
return lineinfo_get(cdev, ip, false);
case GPIO_V2_GET_LINEINFO_WATCH_IOCTL:
return lineinfo_get(cdev, ip, true);
case GPIO_V2_GET_LINE_IOCTL:
return linereq_create(gdev, ip);
case GPIO_GET_LINEINFO_UNWATCH_IOCTL:
return lineinfo_unwatch(cdev, ip);
default:
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
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 lineinfo_changed_ctx *ctx;
struct gpio_desc *desc = data;
if (!test_bit(gpio_chip_hwgpio(desc), cdev->watched_lines))
return NOTIFY_DONE;
/*
* 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);
INIT_WORK(&ctx->work, lineinfo_changed_func);
queue_work(ctx->gdev->line_state_wq, &ctx->work);
return NOTIFY_OK;
}
static int gpio_device_unregistered_notify(struct notifier_block *nb,
unsigned long action, void *data)
{
struct gpio_chardev_data *cdev = container_of(nb,
struct gpio_chardev_data,
device_unregistered_nb);
wake_up_poll(&cdev->wait, EPOLLIN | EPOLLERR);
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;
guard(srcu)(&cdev->gdev->srcu);
if (!rcu_access_pointer(cdev->gdev->chip))
return EPOLLHUP | EPOLLERR;
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;
guard(srcu)(&cdev->gdev->srcu);
if (!rcu_access_pointer(cdev->gdev->chip))
return -ENODEV;
#ifndef CONFIG_GPIO_CDEV_V1
event_size = sizeof(struct gpio_v2_line_info_changed);
if (count < event_size)
return -EINVAL;
#endif
do {
scoped_guard(spinlock, &cdev->wait.lock) {
if (kfifo_is_empty(&cdev->events)) {
if (bytes_read)
return bytes_read;
if (file->f_flags & O_NONBLOCK)
return -EAGAIN;
ret = wait_event_interruptible_locked(cdev->wait,
!kfifo_is_empty(&cdev->events));
if (ret)
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)
return -EINVAL;
#endif
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
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, or negative errno on failure.
*/
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;
guard(srcu)(&gdev->srcu);
/* Fail on open if the backing gpiochip is gone */
if (!rcu_access_pointer(gdev->chip))
return -ENODEV;
cdev = kzalloc(sizeof(*cdev), GFP_KERNEL);
if (!cdev)
return -ENODEV;
cdev->watched_lines = bitmap_zalloc(gdev->ngpio, GFP_KERNEL);
if (!cdev->watched_lines)
goto out_free_cdev;
init_waitqueue_head(&cdev->wait);
INIT_KFIFO(cdev->events);
cdev->gdev = gpio_device_get(gdev);
cdev->lineinfo_changed_nb.notifier_call = lineinfo_changed_notify;
ret = atomic_notifier_chain_register(&gdev->line_state_notifier,
&cdev->lineinfo_changed_nb);
if (ret)
goto out_free_bitmap;
cdev->device_unregistered_nb.notifier_call =
gpio_device_unregistered_notify;
ret = blocking_notifier_chain_register(&gdev->device_notifier,
&cdev->device_unregistered_nb);
if (ret)
goto out_unregister_line_notifier;
file->private_data = cdev;
cdev->fp = file;
ret = nonseekable_open(inode, file);
if (ret)
goto out_unregister_device_notifier;
return ret;
out_unregister_device_notifier:
blocking_notifier_chain_unregister(&gdev->device_notifier,
&cdev->device_unregistered_nb);
out_unregister_line_notifier:
atomic_notifier_chain_unregister(&gdev->line_state_notifier,
&cdev->lineinfo_changed_nb);
out_free_bitmap:
gpio_device_put(gdev);
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, 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;
blocking_notifier_chain_unregister(&gdev->device_notifier,
&cdev->device_unregistered_nb);
atomic_notifier_chain_unregister(&gdev->line_state_notifier,
&cdev->lineinfo_changed_nb);
bitmap_free(cdev->watched_lines);
gpio_device_put(gdev);
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,
.unlocked_ioctl = gpio_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = gpio_ioctl_compat,
#endif
};
int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt)
{
struct gpio_chip *gc;
int ret;
cdev_init(&gdev->chrdev, &gpio_fileops);
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;
guard(srcu)(&gdev->srcu);
gc = srcu_dereference(gdev->chip, &gdev->srcu);
if (!gc)
return -ENODEV;
chip_dbg(gc, "added GPIO chardev (%d:%d)\n", MAJOR(devt), gdev->id);
return 0;
}
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);
}
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