From 0dc11e3ad353e19b1a119e3146c69c0930ecae5f Mon Sep 17 00:00:00 2001 From: Kent Gibson Date: Mon, 28 Sep 2020 08:27:48 +0800 Subject: gpiolib: cdev: gpio_desc_to_lineinfo() should set info offset Set the value of the line info offset in gpio_desc_to_lineinfo(), rather than relying on it being passed in the info. This makes the function behave as you would expect from the name - it generates the line info corresponding to a given GPIO desc. Signed-off-by: Kent Gibson Reviewed-by: Andy Shevchenko Signed-off-by: Bartosz Golaszewski --- drivers/gpio/gpiolib-cdev.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'drivers/gpio/gpiolib-cdev.c') diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index e6c9b78adfc2..81ce2020f17b 100644 --- a/drivers/gpio/gpiolib-cdev.c +++ b/drivers/gpio/gpiolib-cdev.c @@ -752,6 +752,8 @@ static void gpio_desc_to_lineinfo(struct gpio_desc *desc, bool ok_for_pinctrl; unsigned long flags; + info->line_offset = gpio_chip_hwgpio(desc); + /* * This function takes a mutex so we must check this before taking * the spinlock. @@ -933,7 +935,6 @@ static int lineinfo_changed_notify(struct notifier_block *nb, return NOTIFY_DONE; memset(&chg, 0, sizeof(chg)); - chg.info.line_offset = gpio_chip_hwgpio(desc); chg.event_type = action; chg.timestamp = ktime_get_ns(); gpio_desc_to_lineinfo(desc, &chg.info); -- cgit 1.4.1 From 69e4e1368803266d0e06dba86868f64f7b277cde Mon Sep 17 00:00:00 2001 From: Kent Gibson Date: Mon, 28 Sep 2020 08:27:49 +0800 Subject: gpiolib: cdev: replace strncpy() with strscpy() Replace usage of strncpy() with strscpy() to remove -Wstringop-truncation warnings. The structures being populated are zeroed, to prevent stack leakage as they are returned to userspace, so strscpy() performs the equivalent function without the warnings. Reported-by: kernel test robot Signed-off-by: Kent Gibson Reviewed-by: Andy Shevchenko Signed-off-by: Bartosz Golaszewski --- drivers/gpio/gpiolib-cdev.c | 23 +++++++---------------- 1 file changed, 7 insertions(+), 16 deletions(-) (limited to 'drivers/gpio/gpiolib-cdev.c') diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index 81ce2020f17b..86679397d09c 100644 --- a/drivers/gpio/gpiolib-cdev.c +++ b/drivers/gpio/gpiolib-cdev.c @@ -752,6 +752,7 @@ static void gpio_desc_to_lineinfo(struct gpio_desc *desc, bool ok_for_pinctrl; unsigned long flags; + memset(info, 0, sizeof(*info)); info->line_offset = gpio_chip_hwgpio(desc); /* @@ -766,19 +767,11 @@ static void gpio_desc_to_lineinfo(struct gpio_desc *desc, spin_lock_irqsave(&gpio_lock, flags); - if (desc->name) { - strncpy(info->name, desc->name, sizeof(info->name)); - info->name[sizeof(info->name) - 1] = '\0'; - } else { - info->name[0] = '\0'; - } + if (desc->name) + strscpy(info->name, desc->name, sizeof(info->name)); - if (desc->label) { - strncpy(info->consumer, desc->label, sizeof(info->consumer)); - info->consumer[sizeof(info->consumer) - 1] = '\0'; - } else { - info->consumer[0] = '\0'; - } + if (desc->label) + strscpy(info->consumer, desc->label, sizeof(info->consumer)); /* * Userspace only need to know that the kernel is using this GPIO so @@ -842,12 +835,10 @@ static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg) memset(&chipinfo, 0, sizeof(chipinfo)); - strncpy(chipinfo.name, dev_name(&gdev->dev), + strscpy(chipinfo.name, dev_name(&gdev->dev), sizeof(chipinfo.name)); - chipinfo.name[sizeof(chipinfo.name)-1] = '\0'; - strncpy(chipinfo.label, gdev->label, + strscpy(chipinfo.label, gdev->label, sizeof(chipinfo.label)); - chipinfo.label[sizeof(chipinfo.label)-1] = '\0'; chipinfo.lines = gdev->ngpio; if (copy_to_user(ip, &chipinfo, sizeof(chipinfo))) return -EFAULT; -- cgit 1.4.1 From 3c0d9c635ae2b2c6416928271a452017b60e3f98 Mon Sep 17 00:00:00 2001 From: Kent Gibson Date: Mon, 28 Sep 2020 08:27:54 +0800 Subject: gpiolib: cdev: support GPIO_V2_GET_LINE_IOCTL and GPIO_V2_LINE_GET_VALUES_IOCTL Add support for requesting lines using the GPIO_V2_GET_LINE_IOCTL, and returning their current values using GPIO_V2_LINE_GET_VALUES_IOCTL. The struct linereq implementation is based on the v1 struct linehandle implementation. Signed-off-by: Kent Gibson Signed-off-by: Bartosz Golaszewski --- drivers/gpio/gpiolib-cdev.c | 424 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 424 insertions(+) (limited to 'drivers/gpio/gpiolib-cdev.c') diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index 86679397d09c..a5f2256cdf8c 100644 --- a/drivers/gpio/gpiolib-cdev.c +++ b/drivers/gpio/gpiolib-cdev.c @@ -1,7 +1,9 @@ // SPDX-License-Identifier: GPL-2.0 #include +#include #include +#include #include #include #include @@ -24,6 +26,25 @@ #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 @@ -34,6 +55,7 @@ * 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 @@ -376,6 +398,402 @@ 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. + */ +struct line { + struct gpio_desc *desc; +}; + +/** + * 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 + * @lines: the lines held by this line request, with @num_lines elements. + */ +struct linereq { + struct gpio_device *gdev; + const char *label; + u32 num_lines; + 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_VALID_FLAGS \ + (GPIO_V2_LINE_FLAG_ACTIVE_LOW | \ + GPIO_V2_LINE_DIRECTION_FLAGS | \ + GPIO_V2_LINE_DRIVE_FLAGS | \ + GPIO_V2_LINE_BIAS_FLAGS) + +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; + + /* + * 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; + } + 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_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; + 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 (test_bit(didx, vals)) + lv.bits |= BIT_ULL(i); + didx++; + } + } + + if (copy_to_user(ip, &lv, sizeof(lv))) + return -EFAULT; + + 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; + + if (cmd == GPIO_V2_LINE_GET_VALUES_IOCTL) + return linereq_get_values(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 void linereq_free(struct linereq *lr) +{ + unsigned int i; + + for (i = 0; i < lr->num_lines; i++) { + if (lr->lines[i].desc) + gpiod_free(lr->lines[i].desc); + } + 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, + .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); + + /* Make sure this is terminated */ + ulr.consumer[sizeof(ulr.consumer)-1] = '\0'; + if (strlen(ulr.consumer)) { + /* label is only initialized if consumer is set */ + lr->label = kstrdup(ulr.consumer, GFP_KERNEL); + if (!lr->label) { + ret = -ENOMEM; + goto out_free_linereq; + } + } + + 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; + } + + blocking_notifier_call_chain(&desc->gdev->notifier, + GPIOLINE_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 @@ -745,6 +1163,8 @@ out_free_le: return ret; } +#endif /* CONFIG_GPIO_CDEV_V1 */ + static void gpio_desc_to_lineinfo(struct gpio_desc *desc, struct gpioline_info *info) { @@ -843,6 +1263,7 @@ static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg) if (copy_to_user(ip, &chipinfo, sizeof(chipinfo))) return -EFAULT; return 0; +#ifdef CONFIG_GPIO_CDEV_V1 } else if (cmd == GPIO_GET_LINEINFO_IOCTL) { struct gpioline_info lineinfo; @@ -885,6 +1306,9 @@ static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg) } return 0; +#endif /* CONFIG_GPIO_CDEV_V1 */ + } else if (cmd == GPIO_V2_GET_LINE_IOCTL) { + return linereq_create(gdev, ip); } else if (cmd == GPIO_GET_LINEINFO_UNWATCH_IOCTL) { if (copy_from_user(&offset, ip, sizeof(offset))) return -EFAULT; -- cgit 1.4.1 From aad955842d1cdf56d31e600112137d82fd431140 Mon Sep 17 00:00:00 2001 From: Kent Gibson Date: Mon, 28 Sep 2020 08:27:55 +0800 Subject: gpiolib: cdev: support GPIO_V2_GET_LINEINFO_IOCTL and GPIO_V2_GET_LINEINFO_WATCH_IOCTL Add support for GPIO_V2_GET_LINEINFO_IOCTL and GPIO_V2_GET_LINEINFO_WATCH_IOCTL. The core of this change is the event kfifo switching to contain struct gpioline_info_changed_v2, instead of v1 as v2 is richer. The two uAPI versions are mostly independent - other than where they both provide line info changes via reads on the chip fd. As the info change structs differ between v1 and v2, the infowatch implementation tracks which version of the infowatch ioctl, either GPIO_GET_LINEINFO_WATCH_IOCTL or GPIO_V2_GET_LINEINFO_WATCH_IOCTL, initiates the initial watch and returns the corresponding info change struct to the read. The version supported on that fd locks to that version on the first watch request, so subsequent watches from that process must use the same uAPI version. Signed-off-by: Kent Gibson Signed-off-by: Bartosz Golaszewski --- drivers/gpio/gpiolib-cdev.c | 196 +++++++++++++++++++++++++++++++++++++------- 1 file changed, 168 insertions(+), 28 deletions(-) (limited to 'drivers/gpio/gpiolib-cdev.c') diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index a5f2256cdf8c..786e667cdc85 100644 --- a/drivers/gpio/gpiolib-cdev.c +++ b/drivers/gpio/gpiolib-cdev.c @@ -181,7 +181,8 @@ static long linehandle_set_config(struct linehandle_state *lh, } blocking_notifier_call_chain(&desc->gdev->notifier, - GPIOLINE_CHANGED_CONFIG, desc); + GPIO_V2_LINE_CHANGED_CONFIG, + desc); } return 0; } @@ -353,7 +354,7 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip) } blocking_notifier_call_chain(&desc->gdev->notifier, - GPIOLINE_CHANGED_REQUESTED, desc); + GPIO_V2_LINE_CHANGED_REQUESTED, desc); dev_dbg(&gdev->dev, "registered chardev handle for line %d\n", offset); @@ -749,7 +750,7 @@ static int linereq_create(struct gpio_device *gdev, void __user *ip) } blocking_notifier_call_chain(&desc->gdev->notifier, - GPIOLINE_CHANGED_REQUESTED, desc); + GPIO_V2_LINE_CHANGED_REQUESTED, desc); dev_dbg(&gdev->dev, "registered chardev handle for line %d\n", offset); @@ -1096,7 +1097,7 @@ static int lineevent_create(struct gpio_device *gdev, void __user *ip) goto out_free_le; blocking_notifier_call_chain(&desc->gdev->notifier, - GPIOLINE_CHANGED_REQUESTED, desc); + GPIO_V2_LINE_CHANGED_REQUESTED, desc); irq = gpiod_to_irq(desc); if (irq <= 0) { @@ -1163,17 +1164,58 @@ out_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) +{ + 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 gpioline_info *info) + struct gpio_v2_line_info *info) { struct gpio_chip *gc = desc->gdev->chip; bool ok_for_pinctrl; unsigned long flags; memset(info, 0, sizeof(*info)); - info->line_offset = gpio_chip_hwgpio(desc); + info->offset = gpio_chip_hwgpio(desc); /* * This function takes a mutex so we must check this before taking @@ -1183,7 +1225,7 @@ static void gpio_desc_to_lineinfo(struct gpio_desc *desc, * lock common to both frameworks? */ ok_for_pinctrl = - pinctrl_gpio_can_use_line(gc->base + info->line_offset); + pinctrl_gpio_can_use_line(gc->base + info->offset); spin_lock_irqsave(&gpio_lock, flags); @@ -1204,23 +1246,27 @@ static void gpio_desc_to_lineinfo(struct gpio_desc *desc, test_bit(FLAG_EXPORT, &desc->flags) || test_bit(FLAG_SYSFS, &desc->flags) || !ok_for_pinctrl) - info->flags |= GPIOLINE_FLAG_KERNEL; + info->flags |= GPIO_V2_LINE_FLAG_USED; + if (test_bit(FLAG_IS_OUT, &desc->flags)) - info->flags |= GPIOLINE_FLAG_IS_OUT; + 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 |= GPIOLINE_FLAG_ACTIVE_LOW; + info->flags |= GPIO_V2_LINE_FLAG_ACTIVE_LOW; + if (test_bit(FLAG_OPEN_DRAIN, &desc->flags)) - info->flags |= (GPIOLINE_FLAG_OPEN_DRAIN | - GPIOLINE_FLAG_IS_OUT); + info->flags |= GPIO_V2_LINE_FLAG_OPEN_DRAIN; if (test_bit(FLAG_OPEN_SOURCE, &desc->flags)) - info->flags |= (GPIOLINE_FLAG_OPEN_SOURCE | - GPIOLINE_FLAG_IS_OUT); + info->flags |= GPIO_V2_LINE_FLAG_OPEN_SOURCE; + if (test_bit(FLAG_BIAS_DISABLE, &desc->flags)) - info->flags |= GPIOLINE_FLAG_BIAS_DISABLE; + info->flags |= GPIO_V2_LINE_FLAG_BIAS_DISABLED; if (test_bit(FLAG_PULL_DOWN, &desc->flags)) - info->flags |= GPIOLINE_FLAG_BIAS_PULL_DOWN; + info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN; if (test_bit(FLAG_PULL_UP, &desc->flags)) - info->flags |= GPIOLINE_FLAG_BIAS_PULL_UP; + info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_UP; spin_unlock_irqrestore(&gpio_lock, flags); } @@ -1228,11 +1274,65 @@ static void gpio_desc_to_lineinfo(struct gpio_desc *desc, struct gpio_chardev_data { struct gpio_device *gdev; wait_queue_head_t wait; - DECLARE_KFIFO(events, struct gpioline_info_changed, 32); + 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 }; +#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; +} +#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; +} + /* * gpio_ioctl() - ioctl handler for the GPIO chardev */ @@ -1242,7 +1342,6 @@ static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg) struct gpio_device *gdev = cdev->gdev; struct gpio_chip *gc = gdev->chip; void __user *ip = (void __user *)arg; - struct gpio_desc *desc; __u32 offset; /* We fail any subsequent ioctl():s when the chip is gone */ @@ -1265,7 +1364,9 @@ static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg) return 0; #ifdef CONFIG_GPIO_CDEV_V1 } else if (cmd == GPIO_GET_LINEINFO_IOCTL) { + 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; @@ -1275,7 +1376,8 @@ static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg) if (IS_ERR(desc)) return PTR_ERR(desc); - gpio_desc_to_lineinfo(desc, &lineinfo); + gpio_desc_to_lineinfo(desc, &lineinfo_v2); + gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo); if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) return -EFAULT; @@ -1285,7 +1387,9 @@ static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg) } else if (cmd == GPIO_GET_LINEEVENT_IOCTL) { return lineevent_create(gdev, ip); } else if (cmd == GPIO_GET_LINEINFO_WATCH_IOCTL) { + 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; @@ -1295,10 +1399,14 @@ static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg) if (IS_ERR(desc)) return PTR_ERR(desc); + 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); + gpio_desc_to_lineinfo(desc, &lineinfo_v2); + gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo); if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) { clear_bit(lineinfo.line_offset, cdev->watched_lines); @@ -1307,6 +1415,10 @@ static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg) return 0; #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) { @@ -1342,7 +1454,7 @@ 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 gpioline_info_changed chg; + struct gpio_v2_line_info_changed chg; struct gpio_desc *desc = data; int ret; @@ -1351,7 +1463,7 @@ static int lineinfo_changed_notify(struct notifier_block *nb, memset(&chg, 0, sizeof(chg)); chg.event_type = action; - chg.timestamp = ktime_get_ns(); + chg.timestamp_ns = ktime_get_ns(); gpio_desc_to_lineinfo(desc, &chg.info); ret = kfifo_in_spinlocked(&cdev->events, &chg, 1, &cdev->wait.lock); @@ -1382,12 +1494,16 @@ 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 gpioline_info_changed event; + struct gpio_v2_line_info_changed event; ssize_t bytes_read = 0; int ret; + size_t event_size; - if (count < sizeof(event)) +#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); @@ -1409,7 +1525,17 @@ static ssize_t lineinfo_watch_read(struct file *file, char __user *buf, 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) { @@ -1418,9 +1544,23 @@ static ssize_t lineinfo_watch_read(struct file *file, char __user *buf, /* We should never get here. See lineevent_read(). */ } - if (copy_to_user(buf + bytes_read, &event, sizeof(event))) +#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; - bytes_read += sizeof(event); +#endif + bytes_read += event_size; } while (count >= bytes_read + sizeof(event)); return bytes_read; -- cgit 1.4.1 From 73e0341992b68bb3e748134ea8c7473f9d4e279f Mon Sep 17 00:00:00 2001 From: Kent Gibson Date: Mon, 28 Sep 2020 08:27:56 +0800 Subject: gpiolib: cdev: support edge detection for uAPI v2 Add support for edge detection to lines requested using GPIO_V2_GET_LINE_IOCTL. The edge_detector implementation is based on the v1 lineevent implementation. Unlike the v1 implementation, an overflow of the event buffer results in discarding older events, rather than the most recent, so the final event in a burst will correspond to the current state of the line. Signed-off-by: Kent Gibson Signed-off-by: Bartosz Golaszewski --- drivers/gpio/gpiolib-cdev.c | 277 ++++++++++++++++++++++++++++++++++++++++++++ drivers/gpio/gpiolib.c | 2 + drivers/gpio/gpiolib.h | 2 + 3 files changed, 281 insertions(+) (limited to 'drivers/gpio/gpiolib-cdev.c') diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index 786e667cdc85..868fcf89478c 100644 --- a/drivers/gpio/gpiolib-cdev.c +++ b/drivers/gpio/gpiolib-cdev.c @@ -404,9 +404,33 @@ out_free_lh: /** * 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. */ 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; + u32 line_seqno; }; /** @@ -414,12 +438,22 @@ struct line { * @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. * @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 line lines[]; }; @@ -436,12 +470,151 @@ struct linereq { (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; +} + +static void edge_detector_stop(struct line *line) +{ + if (line->irq) { + free_irq(line->irq, line); + line->irq = 0; + } +} + +static int edge_detector_setup(struct line *line, + u64 eflags) +{ + 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 (!eflags) + 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 u64 gpio_v2_line_config_flags(struct gpio_v2_line_config *lc, unsigned int line_idx) { @@ -484,6 +657,11 @@ static int gpio_v2_line_flags_validate(u64 flags) (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 @@ -547,6 +725,11 @@ static void gpio_v2_line_config_flags_to_desc_flags(u64 flags, 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, @@ -636,14 +819,85 @@ static long linereq_ioctl_compat(struct file *file, unsigned int cmd, } #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); @@ -659,6 +913,8 @@ static int linereq_release(struct inode *inode, struct file *file) 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, @@ -698,6 +954,9 @@ static int linereq_create(struct gpio_device *gdev, void __user *ip) lr->gdev = gdev; get_device(&gdev->dev); + for (i = 0; i < ulr.num_lines; i++) + lr->lines[i].req = lr; + /* Make sure this is terminated */ ulr.consumer[sizeof(ulr.consumer)-1] = '\0'; if (strlen(ulr.consumer)) { @@ -709,6 +968,14 @@ static int linereq_create(struct gpio_device *gdev, void __user *ip) } } + 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 */ @@ -747,6 +1014,11 @@ static int linereq_create(struct gpio_device *gdev, void __user *ip) ret = gpiod_direction_input(desc); if (ret) goto out_free_linereq; + + ret = edge_detector_setup(&lr->lines[i], + flags & GPIO_V2_LINE_EDGE_FLAGS); + if (ret) + goto out_free_linereq; } blocking_notifier_call_chain(&desc->gdev->notifier, @@ -1268,6 +1540,11 @@ static void gpio_desc_to_lineinfo(struct gpio_desc *desc, 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; + spin_unlock_irqrestore(&gpio_lock, flags); } diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index dfcff5d24b18..aa20481e9452 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -2092,6 +2092,8 @@ static bool gpiod_free_commit(struct gpio_desc *desc) clear_bit(FLAG_PULL_UP, &desc->flags); clear_bit(FLAG_PULL_DOWN, &desc->flags); clear_bit(FLAG_BIAS_DISABLE, &desc->flags); + clear_bit(FLAG_EDGE_RISING, &desc->flags); + clear_bit(FLAG_EDGE_FALLING, &desc->flags); clear_bit(FLAG_IS_HOGGED, &desc->flags); #ifdef CONFIG_OF_DYNAMIC desc->hog = NULL; diff --git a/drivers/gpio/gpiolib.h b/drivers/gpio/gpiolib.h index 6709f79c02dd..39b356160937 100644 --- a/drivers/gpio/gpiolib.h +++ b/drivers/gpio/gpiolib.h @@ -114,6 +114,8 @@ struct gpio_desc { #define FLAG_PULL_UP 13 /* GPIO has pull up enabled */ #define FLAG_PULL_DOWN 14 /* GPIO has pull down enabled */ #define FLAG_BIAS_DISABLE 15 /* GPIO has pull disabled */ +#define FLAG_EDGE_RISING 16 /* GPIO CDEV detects rising edge events */ +#define FLAG_EDGE_FALLING 17 /* GPIO CDEV detects falling edge events */ /* Connection label */ const char *label; -- cgit 1.4.1 From a54756cb24eafac70ce92bfbd9bb4a4195689fb4 Mon Sep 17 00:00:00 2001 From: Kent Gibson Date: Mon, 28 Sep 2020 08:27:57 +0800 Subject: gpiolib: cdev: support GPIO_V2_LINE_SET_CONFIG_IOCTL Add support for GPIO_V2_LINE_SET_CONFIG_IOCTL, the uAPI v2 line set config ioctl. Signed-off-by: Kent Gibson Signed-off-by: Bartosz Golaszewski --- drivers/gpio/gpiolib-cdev.c | 88 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 88 insertions(+) (limited to 'drivers/gpio/gpiolib-cdev.c') diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index 868fcf89478c..608cdbd1d579 100644 --- a/drivers/gpio/gpiolib-cdev.c +++ b/drivers/gpio/gpiolib-cdev.c @@ -16,6 +16,7 @@ #include #include #include +#include #include #include #include @@ -444,6 +445,8 @@ struct line { * @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 { @@ -454,6 +457,7 @@ struct linereq { u32 event_buffer_size; DECLARE_KFIFO_PTR(events, struct gpio_v2_line_event); atomic_t seqno; + struct mutex config_mutex; struct line lines[]; }; @@ -574,6 +578,8 @@ static void edge_detector_stop(struct line *line) free_irq(line->irq, line); line->irq = 0; } + + line->eflags = 0; } static int edge_detector_setup(struct line *line, @@ -615,6 +621,17 @@ static int edge_detector_setup(struct line *line, return 0; } +static int edge_detector_update(struct line *line, u64 eflags, + bool polarity_change) +{ + if ((line->eflags == eflags) && !polarity_change) + return 0; + + edge_detector_stop(line); + + return edge_detector_setup(line, eflags); +} + static u64 gpio_v2_line_config_flags(struct gpio_v2_line_config *lc, unsigned int line_idx) { @@ -799,6 +816,74 @@ static long linereq_get_values(struct linereq *lr, void __user *ip) return 0; } +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], + 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) { @@ -807,6 +892,8 @@ static long linereq_ioctl(struct file *file, unsigned int cmd, if (cmd == GPIO_V2_LINE_GET_VALUES_IOCTL) return linereq_get_values(lr, ip); + else if (cmd == GPIO_V2_LINE_SET_CONFIG_IOCTL) + return linereq_set_config(lr, ip); return -EINVAL; } @@ -968,6 +1055,7 @@ static int linereq_create(struct gpio_device *gdev, void __user *ip) } } + mutex_init(&lr->config_mutex); init_waitqueue_head(&lr->wait); lr->event_buffer_size = ulr.event_buffer_size; if (lr->event_buffer_size == 0) -- cgit 1.4.1 From 7b8e00d981680ddbbdd9874a7b46e0da58a2da4b Mon Sep 17 00:00:00 2001 From: Kent Gibson Date: Mon, 28 Sep 2020 08:27:58 +0800 Subject: gpiolib: cdev: support GPIO_V2_LINE_SET_VALUES_IOCTL Add support for the GPIO_V2_LINE_SET_VALUES_IOCTL. Signed-off-by: Kent Gibson Signed-off-by: Bartosz Golaszewski --- drivers/gpio/gpiolib-cdev.c | 61 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 61 insertions(+) (limited to 'drivers/gpio/gpiolib-cdev.c') diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index 608cdbd1d579..25536aae3e18 100644 --- a/drivers/gpio/gpiolib-cdev.c +++ b/drivers/gpio/gpiolib-cdev.c @@ -816,6 +816,65 @@ static long linereq_get_values(struct linereq *lr, void __user *ip) 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) { @@ -892,6 +951,8 @@ static long linereq_ioctl(struct file *file, unsigned int cmd, 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); -- cgit 1.4.1 From 65cff70464068a823b3f4a28074000febdce0630 Mon Sep 17 00:00:00 2001 From: Kent Gibson Date: Mon, 28 Sep 2020 08:27:59 +0800 Subject: gpiolib: cdev: support setting debounce Add support for setting debounce on a line via the GPIO uAPI. Where debounce is not supported by hardware, a software debounce is provided. The implementation of the software debouncer waits for the line to be stable for the debounce period before determining if a level change, and a corresponding edge event, has occurred. This provides maximum protection against glitches, but also introduces a debounce_period latency to edge events. The software debouncer is integrated with the edge detection as it utilises the line interrupt, and integration is simpler than getting the two to interwork. Where software debounce AND edge detection is required, the debouncer provides both. Signed-off-by: Kent Gibson Signed-off-by: Bartosz Golaszewski --- drivers/gpio/gpiolib-cdev.c | 247 ++++++++++++++++++++++++++++++++++++++++++-- drivers/gpio/gpiolib.c | 3 + drivers/gpio/gpiolib.h | 4 + 3 files changed, 244 insertions(+), 10 deletions(-) (limited to 'drivers/gpio/gpiolib-cdev.c') diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index 25536aae3e18..73386fcc252d 100644 --- a/drivers/gpio/gpiolib-cdev.c +++ b/drivers/gpio/gpiolib-cdev.c @@ -6,6 +6,7 @@ #include #include #include +#include #include #include #include @@ -22,6 +23,7 @@ #include #include #include +#include #include #include "gpiolib.h" @@ -415,6 +417,9 @@ out_free_lh: * 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; @@ -431,7 +436,28 @@ struct line { */ 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; }; /** @@ -572,6 +598,154 @@ static irqreturn_t edge_irq_handler(int irq, void *p) 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) { @@ -579,12 +753,18 @@ static void edge_detector_stop(struct line *line) line->irq = 0; } + cancel_delayed_work_sync(&line->work); + WRITE_ONCE(line->sw_debounced, 0); line->eflags = 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; @@ -595,8 +775,16 @@ static int edge_detector_setup(struct line *line, 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); + } - if (!eflags) + /* detection disabled or sw debouncer will provide edge detection */ + if (!eflags || READ_ONCE(line->sw_debounced)) return 0; irq = gpiod_to_irq(line->desc); @@ -621,15 +809,31 @@ static int edge_detector_setup(struct line *line, return 0; } -static int edge_detector_update(struct line *line, u64 eflags, - bool polarity_change) +static int edge_detector_update(struct line *line, + struct gpio_v2_line_config *lc, + unsigned int line_idx, + u64 eflags, bool polarity_change) { - if ((line->eflags == eflags) && !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; - edge_detector_stop(line); + /* 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, eflags); + return edge_detector_setup(line, lc, line_idx, eflags); } static u64 gpio_v2_line_config_flags(struct gpio_v2_line_config *lc, @@ -727,6 +931,11 @@ static int gpio_v2_line_config_validate(struct gpio_v2_line_config *lc, 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; } @@ -766,6 +975,7 @@ static long linereq_get_values(struct linereq *lr, void __user *ip) 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. */ @@ -804,7 +1014,11 @@ static long linereq_get_values(struct linereq *lr, void __user *ip) lv.bits = 0; for (didx = 0, i = 0; i < lr->num_lines; i++) { if (lv.mask & BIT_ULL(i)) { - if (test_bit(didx, vals)) + 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++; } @@ -908,7 +1122,7 @@ static long linereq_set_config_unlocked(struct linereq *lr, if (ret) return ret; - ret = edge_detector_update(&lr->lines[i], + ret = edge_detector_update(&lr->lines[i], lc, i, flags & GPIO_V2_LINE_EDGE_FLAGS, polarity_change); if (ret) @@ -1102,8 +1316,11 @@ static int linereq_create(struct gpio_device *gdev, void __user *ip) lr->gdev = gdev; get_device(&gdev->dev); - for (i = 0; i < ulr.num_lines; i++) + 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); + } /* Make sure this is terminated */ ulr.consumer[sizeof(ulr.consumer)-1] = '\0'; @@ -1164,7 +1381,7 @@ static int linereq_create(struct gpio_device *gdev, void __user *ip) if (ret) goto out_free_linereq; - ret = edge_detector_setup(&lr->lines[i], + ret = edge_detector_setup(&lr->lines[i], lc, i, flags & GPIO_V2_LINE_EDGE_FLAGS); if (ret) goto out_free_linereq; @@ -1634,6 +1851,8 @@ static void gpio_desc_to_lineinfo(struct gpio_desc *desc, 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); @@ -1694,6 +1913,14 @@ static void gpio_desc_to_lineinfo(struct gpio_desc *desc, 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); } diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index aa20481e9452..3cdf9effc13a 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -2097,6 +2097,9 @@ static bool gpiod_free_commit(struct gpio_desc *desc) clear_bit(FLAG_IS_HOGGED, &desc->flags); #ifdef CONFIG_OF_DYNAMIC desc->hog = NULL; +#endif +#ifdef CONFIG_GPIO_CDEV + WRITE_ONCE(desc->debounce_period_us, 0); #endif ret = true; } diff --git a/drivers/gpio/gpiolib.h b/drivers/gpio/gpiolib.h index 39b356160937..b674b5bb980e 100644 --- a/drivers/gpio/gpiolib.h +++ b/drivers/gpio/gpiolib.h @@ -124,6 +124,10 @@ struct gpio_desc { #ifdef CONFIG_OF_DYNAMIC struct device_node *hog; #endif +#ifdef CONFIG_GPIO_CDEV + /* debounce period in microseconds */ + unsigned int debounce_period_us; +#endif }; int gpiod_request(struct gpio_desc *desc, const char *label); -- cgit 1.4.1 From f188ac1251b909c2d804a6fee54e4e360754c92f Mon Sep 17 00:00:00 2001 From: Kent Gibson Date: Mon, 5 Oct 2020 15:02:46 +0800 Subject: gpiolib: cdev: switch from kstrdup() to kstrndup() Use kstrndup() to copy line labels from the userspace provided char array, rather than ensuring the char array contains a null terminator and using kstrdup(). Note that the length provided to kstrndup() still assumes that the char array does contain a null terminator, so the maximum string length is one less than the array. This is consistent with the previous behaviour. Suggested-by: Andy Shevchenko Signed-off-by: Kent Gibson Link: https://lore.kernel.org/r/20201005070246.20927-1-warthog618@gmail.com Signed-off-by: Linus Walleij --- drivers/gpio/gpiolib-cdev.c | 27 +++++++++++++-------------- 1 file changed, 13 insertions(+), 14 deletions(-) (limited to 'drivers/gpio/gpiolib-cdev.c') diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index 73386fcc252d..94733aab3224 100644 --- a/drivers/gpio/gpiolib-cdev.c +++ b/drivers/gpio/gpiolib-cdev.c @@ -307,11 +307,11 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip) lh->gdev = gdev; get_device(&gdev->dev); - /* Make sure this is terminated */ - handlereq.consumer_label[sizeof(handlereq.consumer_label)-1] = '\0'; - if (strlen(handlereq.consumer_label)) { - lh->label = kstrdup(handlereq.consumer_label, - GFP_KERNEL); + 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; @@ -1322,11 +1322,10 @@ static int linereq_create(struct gpio_device *gdev, void __user *ip) INIT_DELAYED_WORK(&lr->lines[i].work, debounce_work_func); } - /* Make sure this is terminated */ - ulr.consumer[sizeof(ulr.consumer)-1] = '\0'; - if (strlen(ulr.consumer)) { + if (ulr.consumer[0] != '\0') { /* label is only initialized if consumer is set */ - lr->label = kstrdup(ulr.consumer, GFP_KERNEL); + lr->label = kstrndup(ulr.consumer, sizeof(ulr.consumer) - 1, + GFP_KERNEL); if (!lr->label) { ret = -ENOMEM; goto out_free_linereq; @@ -1711,11 +1710,11 @@ static int lineevent_create(struct gpio_device *gdev, void __user *ip) le->gdev = gdev; get_device(&gdev->dev); - /* Make sure this is terminated */ - eventreq.consumer_label[sizeof(eventreq.consumer_label)-1] = '\0'; - if (strlen(eventreq.consumer_label)) { - le->label = kstrdup(eventreq.consumer_label, - GFP_KERNEL); + 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; -- cgit 1.4.1