1 // SPDX-License-Identifier: GPL-2.0
4 * Copyright 2022 HabanaLabs, Ltd.
9 #include <linux/debugfs.h>
10 #include <linux/device.h>
11 #include <linux/idr.h>
13 #include <drm/drm_accel.h>
14 #include <drm/drm_debugfs.h>
15 #include <drm/drm_drv.h>
16 #include <drm/drm_file.h>
17 #include <drm/drm_ioctl.h>
18 #include <drm/drm_print.h>
20 static DEFINE_SPINLOCK(accel_minor_lock);
21 static struct idr accel_minors_idr;
23 static struct dentry *accel_debugfs_root;
25 static struct device_type accel_sysfs_device_minor = {
29 static char *accel_devnode(const struct device *dev, umode_t *mode)
31 return kasprintf(GFP_KERNEL, "accel/%s", dev_name(dev));
34 static const struct class accel_class = {
36 .devnode = accel_devnode,
39 static int accel_sysfs_init(void)
41 return class_register(&accel_class);
44 static void accel_sysfs_destroy(void)
46 class_unregister(&accel_class);
49 static int accel_name_info(struct seq_file *m, void *data)
51 struct drm_info_node *node = (struct drm_info_node *) m->private;
52 struct drm_minor *minor = node->minor;
53 struct drm_device *dev = minor->dev;
54 struct drm_master *master;
56 mutex_lock(&dev->master_mutex);
58 seq_printf(m, "%s", dev->driver->name);
60 seq_printf(m, " dev=%s", dev_name(dev->dev));
61 if (master && master->unique)
62 seq_printf(m, " master=%s", master->unique);
64 seq_printf(m, " unique=%s", dev->unique);
66 mutex_unlock(&dev->master_mutex);
71 static const struct drm_info_list accel_debugfs_list[] = {
72 {"name", accel_name_info, 0}
74 #define ACCEL_DEBUGFS_ENTRIES ARRAY_SIZE(accel_debugfs_list)
77 * accel_debugfs_init() - Initialize debugfs for device
78 * @dev: Pointer to the device instance.
80 * This function creates a root directory for the device in debugfs.
82 void accel_debugfs_init(struct drm_device *dev)
84 drm_debugfs_dev_init(dev, accel_debugfs_root);
88 * accel_debugfs_register() - Register debugfs for device
89 * @dev: Pointer to the device instance.
91 * Creates common files for accelerators.
93 void accel_debugfs_register(struct drm_device *dev)
95 struct drm_minor *minor = dev->accel;
97 minor->debugfs_root = dev->debugfs_root;
99 drm_debugfs_create_files(accel_debugfs_list, ACCEL_DEBUGFS_ENTRIES,
100 dev->debugfs_root, minor);
104 * accel_set_device_instance_params() - Set some device parameters for accel device
105 * @kdev: Pointer to the device instance.
106 * @index: The minor's index
108 * This function creates the dev_t of the device using the accel major and
109 * the device's minor number. In addition, it sets the class and type of the
110 * device instance to the accel sysfs class and device type, respectively.
112 void accel_set_device_instance_params(struct device *kdev, int index)
114 kdev->devt = MKDEV(ACCEL_MAJOR, index);
115 kdev->class = &accel_class;
116 kdev->type = &accel_sysfs_device_minor;
120 * accel_minor_alloc() - Allocates a new accel minor
122 * This function access the accel minors idr and allocates from it
123 * a new id to represent a new accel minor
125 * Return: A new id on success or error code in case idr_alloc failed
127 int accel_minor_alloc(void)
132 spin_lock_irqsave(&accel_minor_lock, flags);
133 r = idr_alloc(&accel_minors_idr, NULL, 0, ACCEL_MAX_MINORS, GFP_NOWAIT);
134 spin_unlock_irqrestore(&accel_minor_lock, flags);
140 * accel_minor_remove() - Remove an accel minor
141 * @index: The minor id to remove.
143 * This function access the accel minors idr and removes from
144 * it the member with the id that is passed to this function.
146 void accel_minor_remove(int index)
150 spin_lock_irqsave(&accel_minor_lock, flags);
151 idr_remove(&accel_minors_idr, index);
152 spin_unlock_irqrestore(&accel_minor_lock, flags);
156 * accel_minor_replace() - Replace minor pointer in accel minors idr.
157 * @minor: Pointer to the new minor.
158 * @index: The minor id to replace.
160 * This function access the accel minors idr structure and replaces the pointer
161 * that is associated with an existing id. Because the minor pointer can be
162 * NULL, we need to explicitly pass the index.
164 * Return: 0 for success, negative value for error
166 void accel_minor_replace(struct drm_minor *minor, int index)
170 spin_lock_irqsave(&accel_minor_lock, flags);
171 idr_replace(&accel_minors_idr, minor, index);
172 spin_unlock_irqrestore(&accel_minor_lock, flags);
176 * Looks up the given minor-ID and returns the respective DRM-minor object. The
177 * refence-count of the underlying device is increased so you must release this
178 * object with accel_minor_release().
180 * The object can be only a drm_minor that represents an accel device.
182 * As long as you hold this minor, it is guaranteed that the object and the
183 * minor->dev pointer will stay valid! However, the device may get unplugged and
184 * unregistered while you hold the minor.
186 static struct drm_minor *accel_minor_acquire(unsigned int minor_id)
188 struct drm_minor *minor;
191 spin_lock_irqsave(&accel_minor_lock, flags);
192 minor = idr_find(&accel_minors_idr, minor_id);
194 drm_dev_get(minor->dev);
195 spin_unlock_irqrestore(&accel_minor_lock, flags);
198 return ERR_PTR(-ENODEV);
199 } else if (drm_dev_is_unplugged(minor->dev)) {
200 drm_dev_put(minor->dev);
201 return ERR_PTR(-ENODEV);
207 static void accel_minor_release(struct drm_minor *minor)
209 drm_dev_put(minor->dev);
213 * accel_open - open method for ACCEL file
214 * @inode: device inode
215 * @filp: file pointer.
217 * This function must be used by drivers as their &file_operations.open method.
218 * It looks up the correct ACCEL device and instantiates all the per-file
219 * resources for it. It also calls the &drm_driver.open driver callback.
221 * Return: 0 on success or negative errno value on failure.
223 int accel_open(struct inode *inode, struct file *filp)
225 struct drm_device *dev;
226 struct drm_minor *minor;
229 minor = accel_minor_acquire(iminor(inode));
231 return PTR_ERR(minor);
235 atomic_fetch_inc(&dev->open_count);
237 /* share address_space across all char-devs of a single device */
238 filp->f_mapping = dev->anon_inode->i_mapping;
240 retcode = drm_open_helper(filp, minor);
247 atomic_dec(&dev->open_count);
248 accel_minor_release(minor);
251 EXPORT_SYMBOL_GPL(accel_open);
253 static int accel_stub_open(struct inode *inode, struct file *filp)
255 const struct file_operations *new_fops;
256 struct drm_minor *minor;
259 minor = accel_minor_acquire(iminor(inode));
261 return PTR_ERR(minor);
263 new_fops = fops_get(minor->dev->driver->fops);
269 replace_fops(filp, new_fops);
270 if (filp->f_op->open)
271 err = filp->f_op->open(inode, filp);
276 accel_minor_release(minor);
281 static const struct file_operations accel_stub_fops = {
282 .owner = THIS_MODULE,
283 .open = accel_stub_open,
284 .llseek = noop_llseek,
287 void accel_core_exit(void)
289 unregister_chrdev(ACCEL_MAJOR, "accel");
290 debugfs_remove(accel_debugfs_root);
291 accel_sysfs_destroy();
292 idr_destroy(&accel_minors_idr);
295 int __init accel_core_init(void)
299 idr_init(&accel_minors_idr);
301 ret = accel_sysfs_init();
303 DRM_ERROR("Cannot create ACCEL class: %d\n", ret);
307 accel_debugfs_root = debugfs_create_dir("accel", NULL);
309 ret = register_chrdev(ACCEL_MAJOR, "accel", &accel_stub_fops);
311 DRM_ERROR("Cannot register ACCEL major: %d\n", ret);
315 * Any cleanup due to errors will be done in drm_core_exit() that
316 * will call accel_core_exit()