// SPDX-License-Identifier: GPL-2.0
#include <linux/anon_inodes.h>
+#include <linux/atomic.h>
#include <linux/bitmap.h>
+#include <linux/build_bug.h>
#include <linux/cdev.h>
#include <linux/compat.h>
#include <linux/device.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
* 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
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
return ret;
}
+#endif /* CONFIG_GPIO_CDEV_V1 */
+
static void gpio_desc_to_lineinfo(struct gpio_desc *desc,
struct gpioline_info *info)
{
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;
}
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;
projects / platform / kernel / linux-starfive.git / commitdiff