1// SPDX-License-Identifier: GPL-2.0
2
3/*
4 * Copyright 2022 HabanaLabs, Ltd.
5 * All Rights Reserved.
6 *
7 */
8
9#include <linux/debugfs.h>
10#include <linux/device.h>
11#include <linux/idr.h>
12
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>
19
20static DEFINE_SPINLOCK(accel_minor_lock);
21static struct idr accel_minors_idr;
22
23static struct dentry *accel_debugfs_root;
24
25static struct device_type accel_sysfs_device_minor = {
26 .name = "accel_minor"
27};
28
29static char *accel_devnode(const struct device *dev, umode_t *mode)
30{
31 return kasprintf(GFP_KERNEL, fmt: "accel/%s", dev_name(dev));
32}
33
34static const struct class accel_class = {
35 .name = "accel",
36 .devnode = accel_devnode,
37};
38
39static int accel_sysfs_init(void)
40{
41 return class_register(class: &accel_class);
42}
43
44static void accel_sysfs_destroy(void)
45{
46 class_unregister(class: &accel_class);
47}
48
49static int accel_name_info(struct seq_file *m, void *data)
50{
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;
55
56 mutex_lock(&dev->master_mutex);
57 master = dev->master;
58 seq_printf(m, fmt: "%s", dev->driver->name);
59 if (dev->dev)
60 seq_printf(m, fmt: " dev=%s", dev_name(dev: dev->dev));
61 if (master && master->unique)
62 seq_printf(m, fmt: " master=%s", master->unique);
63 if (dev->unique)
64 seq_printf(m, fmt: " unique=%s", dev->unique);
65 seq_puts(m, s: "\n");
66 mutex_unlock(lock: &dev->master_mutex);
67
68 return 0;
69}
70
71static const struct drm_info_list accel_debugfs_list[] = {
72 {"name", accel_name_info, 0}
73};
74#define ACCEL_DEBUGFS_ENTRIES ARRAY_SIZE(accel_debugfs_list)
75
76/**
77 * accel_debugfs_init() - Initialize debugfs for device
78 * @dev: Pointer to the device instance.
79 *
80 * This function creates a root directory for the device in debugfs.
81 */
82void accel_debugfs_init(struct drm_device *dev)
83{
84 drm_debugfs_dev_init(dev, root: accel_debugfs_root);
85}
86
87/**
88 * accel_debugfs_register() - Register debugfs for device
89 * @dev: Pointer to the device instance.
90 *
91 * Creates common files for accelerators.
92 */
93void accel_debugfs_register(struct drm_device *dev)
94{
95 struct drm_minor *minor = dev->accel;
96
97 minor->debugfs_root = dev->debugfs_root;
98
99 drm_debugfs_create_files(files: accel_debugfs_list, ACCEL_DEBUGFS_ENTRIES,
100 root: dev->debugfs_root, minor);
101}
102
103/**
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
107 *
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.
111 */
112void accel_set_device_instance_params(struct device *kdev, int index)
113{
114 kdev->devt = MKDEV(ACCEL_MAJOR, index);
115 kdev->class = &accel_class;
116 kdev->type = &accel_sysfs_device_minor;
117}
118
119/**
120 * accel_minor_alloc() - Allocates a new accel minor
121 *
122 * This function access the accel minors idr and allocates from it
123 * a new id to represent a new accel minor
124 *
125 * Return: A new id on success or error code in case idr_alloc failed
126 */
127int accel_minor_alloc(void)
128{
129 unsigned long flags;
130 int r;
131
132 spin_lock_irqsave(&accel_minor_lock, flags);
133 r = idr_alloc(&accel_minors_idr, NULL, start: 0, ACCEL_MAX_MINORS, GFP_NOWAIT);
134 spin_unlock_irqrestore(lock: &accel_minor_lock, flags);
135
136 return r;
137}
138
139/**
140 * accel_minor_remove() - Remove an accel minor
141 * @index: The minor id to remove.
142 *
143 * This function access the accel minors idr and removes from
144 * it the member with the id that is passed to this function.
145 */
146void accel_minor_remove(int index)
147{
148 unsigned long flags;
149
150 spin_lock_irqsave(&accel_minor_lock, flags);
151 idr_remove(&accel_minors_idr, id: index);
152 spin_unlock_irqrestore(lock: &accel_minor_lock, flags);
153}
154
155/**
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.
159 *
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.
163 *
164 * Return: 0 for success, negative value for error
165 */
166void accel_minor_replace(struct drm_minor *minor, int index)
167{
168 unsigned long flags;
169
170 spin_lock_irqsave(&accel_minor_lock, flags);
171 idr_replace(&accel_minors_idr, minor, id: index);
172 spin_unlock_irqrestore(lock: &accel_minor_lock, flags);
173}
174
175/*
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().
179 *
180 * The object can be only a drm_minor that represents an accel device.
181 *
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.
185 */
186static struct drm_minor *accel_minor_acquire(unsigned int minor_id)
187{
188 struct drm_minor *minor;
189 unsigned long flags;
190
191 spin_lock_irqsave(&accel_minor_lock, flags);
192 minor = idr_find(&accel_minors_idr, id: minor_id);
193 if (minor)
194 drm_dev_get(dev: minor->dev);
195 spin_unlock_irqrestore(lock: &accel_minor_lock, flags);
196
197 if (!minor) {
198 return ERR_PTR(error: -ENODEV);
199 } else if (drm_dev_is_unplugged(dev: minor->dev)) {
200 drm_dev_put(dev: minor->dev);
201 return ERR_PTR(error: -ENODEV);
202 }
203
204 return minor;
205}
206
207static void accel_minor_release(struct drm_minor *minor)
208{
209 drm_dev_put(dev: minor->dev);
210}
211
212/**
213 * accel_open - open method for ACCEL file
214 * @inode: device inode
215 * @filp: file pointer.
216 *
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.
220 *
221 * Return: 0 on success or negative errno value on failure.
222 */
223int accel_open(struct inode *inode, struct file *filp)
224{
225 struct drm_device *dev;
226 struct drm_minor *minor;
227 int retcode;
228
229 minor = accel_minor_acquire(minor_id: iminor(inode));
230 if (IS_ERR(ptr: minor))
231 return PTR_ERR(ptr: minor);
232
233 dev = minor->dev;
234
235 atomic_fetch_inc(v: &dev->open_count);
236
237 /* share address_space across all char-devs of a single device */
238 filp->f_mapping = dev->anon_inode->i_mapping;
239
240 retcode = drm_open_helper(filp, minor);
241 if (retcode)
242 goto err_undo;
243
244 return 0;
245
246err_undo:
247 atomic_dec(v: &dev->open_count);
248 accel_minor_release(minor);
249 return retcode;
250}
251EXPORT_SYMBOL_GPL(accel_open);
252
253static int accel_stub_open(struct inode *inode, struct file *filp)
254{
255 const struct file_operations *new_fops;
256 struct drm_minor *minor;
257 int err;
258
259 minor = accel_minor_acquire(minor_id: iminor(inode));
260 if (IS_ERR(ptr: minor))
261 return PTR_ERR(ptr: minor);
262
263 new_fops = fops_get(minor->dev->driver->fops);
264 if (!new_fops) {
265 err = -ENODEV;
266 goto out;
267 }
268
269 replace_fops(filp, new_fops);
270 if (filp->f_op->open)
271 err = filp->f_op->open(inode, filp);
272 else
273 err = 0;
274
275out:
276 accel_minor_release(minor);
277
278 return err;
279}
280
281static const struct file_operations accel_stub_fops = {
282 .owner = THIS_MODULE,
283 .open = accel_stub_open,
284 .llseek = noop_llseek,
285};
286
287void accel_core_exit(void)
288{
289 unregister_chrdev(ACCEL_MAJOR, name: "accel");
290 debugfs_remove(dentry: accel_debugfs_root);
291 accel_sysfs_destroy();
292 idr_destroy(&accel_minors_idr);
293}
294
295int __init accel_core_init(void)
296{
297 int ret;
298
299 idr_init(idr: &accel_minors_idr);
300
301 ret = accel_sysfs_init();
302 if (ret < 0) {
303 DRM_ERROR("Cannot create ACCEL class: %d\n", ret);
304 goto error;
305 }
306
307 accel_debugfs_root = debugfs_create_dir(name: "accel", NULL);
308
309 ret = register_chrdev(ACCEL_MAJOR, name: "accel", fops: &accel_stub_fops);
310 if (ret < 0)
311 DRM_ERROR("Cannot register ACCEL major: %d\n", ret);
312
313error:
314 /*
315 * Any cleanup due to errors will be done in drm_core_exit() that
316 * will call accel_core_exit()
317 */
318 return ret;
319}
320

source code of linux/drivers/accel/drm_accel.c