| /* |
| * Copyright © 2015 Intel Corporation |
| * |
| * Permission is hereby granted, free of charge, to any person obtaining a |
| * copy of this software and associated documentation files (the "Software"), |
| * to deal in the Software without restriction, including without limitation |
| * the rights to use, copy, modify, merge, publish, distribute, sublicense, |
| * and/or sell copies of the Software, and to permit persons to whom the |
| * Software is furnished to do so, subject to the following conditions: |
| * |
| * The above copyright notice and this permission notice (including the next |
| * paragraph) shall be included in all copies or substantial portions of the |
| * Software. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
| * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING |
| * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS |
| * IN THE SOFTWARE. |
| * |
| * Authors: |
| * Rafael Antognolli <rafael.antognolli@intel.com> |
| * |
| */ |
| |
| #include <linux/device.h> |
| #include <linux/fs.h> |
| #include <linux/init.h> |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/sched/signal.h> |
| #include <linux/slab.h> |
| #include <linux/uaccess.h> |
| #include <linux/uio.h> |
| |
| #include <drm/drm_crtc.h> |
| #include <drm/drm_dp_helper.h> |
| #include <drm/drm_dp_mst_helper.h> |
| #include <drm/drm_print.h> |
| |
| #include "drm_crtc_helper_internal.h" |
| |
| struct drm_dp_aux_dev { |
| unsigned index; |
| struct drm_dp_aux *aux; |
| struct device *dev; |
| struct kref refcount; |
| atomic_t usecount; |
| }; |
| |
| #define DRM_AUX_MINORS 256 |
| #define AUX_MAX_OFFSET (1 << 20) |
| static DEFINE_IDR(aux_idr); |
| static DEFINE_MUTEX(aux_idr_mutex); |
| static struct class *drm_dp_aux_dev_class; |
| static int drm_dev_major = -1; |
| |
| static struct drm_dp_aux_dev *drm_dp_aux_dev_get_by_minor(unsigned index) |
| { |
| struct drm_dp_aux_dev *aux_dev = NULL; |
| |
| mutex_lock(&aux_idr_mutex); |
| aux_dev = idr_find(&aux_idr, index); |
| if (aux_dev && !kref_get_unless_zero(&aux_dev->refcount)) |
| aux_dev = NULL; |
| mutex_unlock(&aux_idr_mutex); |
| |
| return aux_dev; |
| } |
| |
| static struct drm_dp_aux_dev *alloc_drm_dp_aux_dev(struct drm_dp_aux *aux) |
| { |
| struct drm_dp_aux_dev *aux_dev; |
| int index; |
| |
| aux_dev = kzalloc(sizeof(*aux_dev), GFP_KERNEL); |
| if (!aux_dev) |
| return ERR_PTR(-ENOMEM); |
| aux_dev->aux = aux; |
| atomic_set(&aux_dev->usecount, 1); |
| kref_init(&aux_dev->refcount); |
| |
| mutex_lock(&aux_idr_mutex); |
| index = idr_alloc(&aux_idr, aux_dev, 0, DRM_AUX_MINORS, GFP_KERNEL); |
| mutex_unlock(&aux_idr_mutex); |
| if (index < 0) { |
| kfree(aux_dev); |
| return ERR_PTR(index); |
| } |
| aux_dev->index = index; |
| |
| return aux_dev; |
| } |
| |
| static void release_drm_dp_aux_dev(struct kref *ref) |
| { |
| struct drm_dp_aux_dev *aux_dev = |
| container_of(ref, struct drm_dp_aux_dev, refcount); |
| |
| kfree(aux_dev); |
| } |
| |
| static ssize_t name_show(struct device *dev, |
| struct device_attribute *attr, char *buf) |
| { |
| ssize_t res; |
| struct drm_dp_aux_dev *aux_dev = |
| drm_dp_aux_dev_get_by_minor(MINOR(dev->devt)); |
| |
| if (!aux_dev) |
| return -ENODEV; |
| |
| res = sprintf(buf, "%s\n", aux_dev->aux->name); |
| kref_put(&aux_dev->refcount, release_drm_dp_aux_dev); |
| |
| return res; |
| } |
| static DEVICE_ATTR_RO(name); |
| |
| static struct attribute *drm_dp_aux_attrs[] = { |
| &dev_attr_name.attr, |
| NULL, |
| }; |
| ATTRIBUTE_GROUPS(drm_dp_aux); |
| |
| static int auxdev_open(struct inode *inode, struct file *file) |
| { |
| unsigned int minor = iminor(inode); |
| struct drm_dp_aux_dev *aux_dev; |
| |
| aux_dev = drm_dp_aux_dev_get_by_minor(minor); |
| if (!aux_dev) |
| return -ENODEV; |
| |
| file->private_data = aux_dev; |
| return 0; |
| } |
| |
| static loff_t auxdev_llseek(struct file *file, loff_t offset, int whence) |
| { |
| return fixed_size_llseek(file, offset, whence, AUX_MAX_OFFSET); |
| } |
| |
| static ssize_t auxdev_read_iter(struct kiocb *iocb, struct iov_iter *to) |
| { |
| struct drm_dp_aux_dev *aux_dev = iocb->ki_filp->private_data; |
| loff_t pos = iocb->ki_pos; |
| ssize_t res = 0; |
| |
| if (!atomic_inc_not_zero(&aux_dev->usecount)) |
| return -ENODEV; |
| |
| iov_iter_truncate(to, AUX_MAX_OFFSET - pos); |
| |
| while (iov_iter_count(to)) { |
| uint8_t buf[DP_AUX_MAX_PAYLOAD_BYTES]; |
| ssize_t todo = min(iov_iter_count(to), sizeof(buf)); |
| |
| if (signal_pending(current)) { |
| res = -ERESTARTSYS; |
| break; |
| } |
| |
| if (aux_dev->aux->is_remote) |
| res = drm_dp_mst_dpcd_read(aux_dev->aux, pos, buf, |
| todo); |
| else |
| res = drm_dp_dpcd_read(aux_dev->aux, pos, buf, todo); |
| |
| if (res <= 0) |
| break; |
| |
| if (copy_to_iter(buf, res, to) != res) { |
| res = -EFAULT; |
| break; |
| } |
| |
| pos += res; |
| } |
| |
| if (pos != iocb->ki_pos) |
| res = pos - iocb->ki_pos; |
| iocb->ki_pos = pos; |
| |
| if (atomic_dec_and_test(&aux_dev->usecount)) |
| wake_up_var(&aux_dev->usecount); |
| |
| return res; |
| } |
| |
| static ssize_t auxdev_write_iter(struct kiocb *iocb, struct iov_iter *from) |
| { |
| struct drm_dp_aux_dev *aux_dev = iocb->ki_filp->private_data; |
| loff_t pos = iocb->ki_pos; |
| ssize_t res = 0; |
| |
| if (!atomic_inc_not_zero(&aux_dev->usecount)) |
| return -ENODEV; |
| |
| iov_iter_truncate(from, AUX_MAX_OFFSET - pos); |
| |
| while (iov_iter_count(from)) { |
| uint8_t buf[DP_AUX_MAX_PAYLOAD_BYTES]; |
| ssize_t todo = min(iov_iter_count(from), sizeof(buf)); |
| |
| if (signal_pending(current)) { |
| res = -ERESTARTSYS; |
| break; |
| } |
| |
| if (!copy_from_iter_full(buf, todo, from)) { |
| res = -EFAULT; |
| break; |
| } |
| |
| if (aux_dev->aux->is_remote) |
| res = drm_dp_mst_dpcd_write(aux_dev->aux, pos, buf, |
| todo); |
| else |
| res = drm_dp_dpcd_write(aux_dev->aux, pos, buf, todo); |
| |
| if (res <= 0) |
| break; |
| |
| pos += res; |
| } |
| |
| if (pos != iocb->ki_pos) |
| res = pos - iocb->ki_pos; |
| iocb->ki_pos = pos; |
| |
| if (atomic_dec_and_test(&aux_dev->usecount)) |
| wake_up_var(&aux_dev->usecount); |
| |
| return res; |
| } |
| |
| static int auxdev_release(struct inode *inode, struct file *file) |
| { |
| struct drm_dp_aux_dev *aux_dev = file->private_data; |
| |
| kref_put(&aux_dev->refcount, release_drm_dp_aux_dev); |
| return 0; |
| } |
| |
| static const struct file_operations auxdev_fops = { |
| .owner = THIS_MODULE, |
| .llseek = auxdev_llseek, |
| .read_iter = auxdev_read_iter, |
| .write_iter = auxdev_write_iter, |
| .open = auxdev_open, |
| .release = auxdev_release, |
| }; |
| |
| #define to_auxdev(d) container_of(d, struct drm_dp_aux_dev, aux) |
| |
| static struct drm_dp_aux_dev *drm_dp_aux_dev_get_by_aux(struct drm_dp_aux *aux) |
| { |
| struct drm_dp_aux_dev *iter, *aux_dev = NULL; |
| int id; |
| |
| /* don't increase kref count here because this function should only be |
| * used by drm_dp_aux_unregister_devnode. Thus, it will always have at |
| * least one reference - the one that drm_dp_aux_register_devnode |
| * created |
| */ |
| mutex_lock(&aux_idr_mutex); |
| idr_for_each_entry(&aux_idr, iter, id) { |
| if (iter->aux == aux) { |
| aux_dev = iter; |
| break; |
| } |
| } |
| mutex_unlock(&aux_idr_mutex); |
| return aux_dev; |
| } |
| |
| void drm_dp_aux_unregister_devnode(struct drm_dp_aux *aux) |
| { |
| struct drm_dp_aux_dev *aux_dev; |
| unsigned int minor; |
| |
| aux_dev = drm_dp_aux_dev_get_by_aux(aux); |
| if (!aux_dev) /* attach must have failed */ |
| return; |
| |
| mutex_lock(&aux_idr_mutex); |
| idr_remove(&aux_idr, aux_dev->index); |
| mutex_unlock(&aux_idr_mutex); |
| |
| atomic_dec(&aux_dev->usecount); |
| wait_var_event(&aux_dev->usecount, !atomic_read(&aux_dev->usecount)); |
| |
| minor = aux_dev->index; |
| if (aux_dev->dev) |
| device_destroy(drm_dp_aux_dev_class, |
| MKDEV(drm_dev_major, minor)); |
| |
| DRM_DEBUG("drm_dp_aux_dev: aux [%s] unregistering\n", aux->name); |
| kref_put(&aux_dev->refcount, release_drm_dp_aux_dev); |
| } |
| |
| int drm_dp_aux_register_devnode(struct drm_dp_aux *aux) |
| { |
| struct drm_dp_aux_dev *aux_dev; |
| int res; |
| |
| aux_dev = alloc_drm_dp_aux_dev(aux); |
| if (IS_ERR(aux_dev)) |
| return PTR_ERR(aux_dev); |
| |
| aux_dev->dev = device_create(drm_dp_aux_dev_class, aux->dev, |
| MKDEV(drm_dev_major, aux_dev->index), NULL, |
| "drm_dp_aux%d", aux_dev->index); |
| if (IS_ERR(aux_dev->dev)) { |
| res = PTR_ERR(aux_dev->dev); |
| aux_dev->dev = NULL; |
| goto error; |
| } |
| |
| DRM_DEBUG("drm_dp_aux_dev: aux [%s] registered as minor %d\n", |
| aux->name, aux_dev->index); |
| return 0; |
| error: |
| drm_dp_aux_unregister_devnode(aux); |
| return res; |
| } |
| |
| int drm_dp_aux_dev_init(void) |
| { |
| int res; |
| |
| drm_dp_aux_dev_class = class_create(THIS_MODULE, "drm_dp_aux_dev"); |
| if (IS_ERR(drm_dp_aux_dev_class)) { |
| return PTR_ERR(drm_dp_aux_dev_class); |
| } |
| drm_dp_aux_dev_class->dev_groups = drm_dp_aux_groups; |
| |
| res = register_chrdev(0, "aux", &auxdev_fops); |
| if (res < 0) |
| goto out; |
| drm_dev_major = res; |
| |
| return 0; |
| out: |
| class_destroy(drm_dp_aux_dev_class); |
| return res; |
| } |
| |
| void drm_dp_aux_dev_exit(void) |
| { |
| unregister_chrdev(drm_dev_major, "aux"); |
| class_destroy(drm_dp_aux_dev_class); |
| } |