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_auth.h>
15#include <drm/drm_debugfs.h>
16#include <drm/drm_drv.h>
17#include <drm/drm_file.h>
18#include <drm/drm_ioctl.h>
19#include <drm/drm_print.h>
20
21static DEFINE_SPINLOCK(accel_minor_lock);
22static struct idr accel_minors_idr;
23
24static struct dentry *accel_debugfs_root;
25
26static const struct device_type accel_sysfs_device_minor = {
27	.name = "accel_minor"
28};
29
30static char *accel_devnode(const struct device *dev, umode_t *mode)
31{
32	return kasprintf(GFP_KERNEL, "accel/%s", dev_name(dev));
33}
34
35static const struct class accel_class = {
36	.name = "accel",
37	.devnode = accel_devnode,
38};
39
40static int accel_sysfs_init(void)
41{
42	return class_register(&accel_class);
43}
44
45static void accel_sysfs_destroy(void)
46{
47	class_unregister(&accel_class);
48}
49
50static int accel_name_info(struct seq_file *m, void *data)
51{
52	struct drm_info_node *node = (struct drm_info_node *) m->private;
53	struct drm_minor *minor = node->minor;
54	struct drm_device *dev = minor->dev;
55	struct drm_master *master;
56
57	mutex_lock(&dev->master_mutex);
58	master = dev->master;
59	seq_printf(m, "%s", dev->driver->name);
60	if (dev->dev)
61		seq_printf(m, " dev=%s", dev_name(dev->dev));
62	if (master && master->unique)
63		seq_printf(m, " master=%s", master->unique);
64	if (dev->unique)
65		seq_printf(m, " unique=%s", dev->unique);
66	seq_puts(m, "\n");
67	mutex_unlock(&dev->master_mutex);
68
69	return 0;
70}
71
72static const struct drm_info_list accel_debugfs_list[] = {
73	{"name", accel_name_info, 0}
74};
75#define ACCEL_DEBUGFS_ENTRIES ARRAY_SIZE(accel_debugfs_list)
76
77/**
78 * accel_debugfs_init() - Initialize debugfs for device
79 * @dev: Pointer to the device instance.
80 *
81 * This function creates a root directory for the device in debugfs.
82 */
83void accel_debugfs_init(struct drm_device *dev)
84{
85	drm_debugfs_dev_init(dev, accel_debugfs_root);
86}
87
88/**
89 * accel_debugfs_register() - Register debugfs for device
90 * @dev: Pointer to the device instance.
91 *
92 * Creates common files for accelerators.
93 */
94void accel_debugfs_register(struct drm_device *dev)
95{
96	struct drm_minor *minor = dev->accel;
97
98	minor->debugfs_root = dev->debugfs_root;
99
100	drm_debugfs_create_files(accel_debugfs_list, ACCEL_DEBUGFS_ENTRIES,
101				 dev->debugfs_root, minor);
102}
103
104/**
105 * accel_set_device_instance_params() - Set some device parameters for accel device
106 * @kdev: Pointer to the device instance.
107 * @index: The minor's index
108 *
109 * This function creates the dev_t of the device using the accel major and
110 * the device's minor number. In addition, it sets the class and type of the
111 * device instance to the accel sysfs class and device type, respectively.
112 */
113void accel_set_device_instance_params(struct device *kdev, int index)
114{
115	kdev->devt = MKDEV(ACCEL_MAJOR, index);
116	kdev->class = &accel_class;
117	kdev->type = &accel_sysfs_device_minor;
118}
119
120/**
121 * accel_minor_alloc() - Allocates a new accel minor
122 *
123 * This function access the accel minors idr and allocates from it
124 * a new id to represent a new accel minor
125 *
126 * Return: A new id on success or error code in case idr_alloc failed
127 */
128int accel_minor_alloc(void)
129{
130	unsigned long flags;
131	int r;
132
133	spin_lock_irqsave(&accel_minor_lock, flags);
134	r = idr_alloc(&accel_minors_idr, NULL, 0, ACCEL_MAX_MINORS, GFP_NOWAIT);
135	spin_unlock_irqrestore(&accel_minor_lock, flags);
136
137	return r;
138}
139
140/**
141 * accel_minor_remove() - Remove an accel minor
142 * @index: The minor id to remove.
143 *
144 * This function access the accel minors idr and removes from
145 * it the member with the id that is passed to this function.
146 */
147void accel_minor_remove(int index)
148{
149	unsigned long flags;
150
151	spin_lock_irqsave(&accel_minor_lock, flags);
152	idr_remove(&accel_minors_idr, index);
153	spin_unlock_irqrestore(&accel_minor_lock, flags);
154}
155
156/**
157 * accel_minor_replace() - Replace minor pointer in accel minors idr.
158 * @minor: Pointer to the new minor.
159 * @index: The minor id to replace.
160 *
161 * This function access the accel minors idr structure and replaces the pointer
162 * that is associated with an existing id. Because the minor pointer can be
163 * NULL, we need to explicitly pass the index.
164 *
165 * Return: 0 for success, negative value for error
166 */
167void accel_minor_replace(struct drm_minor *minor, int index)
168{
169	unsigned long flags;
170
171	spin_lock_irqsave(&accel_minor_lock, flags);
172	idr_replace(&accel_minors_idr, minor, index);
173	spin_unlock_irqrestore(&accel_minor_lock, flags);
174}
175
176/*
177 * Looks up the given minor-ID and returns the respective DRM-minor object. The
178 * refence-count of the underlying device is increased so you must release this
179 * object with accel_minor_release().
180 *
181 * The object can be only a drm_minor that represents an accel device.
182 *
183 * As long as you hold this minor, it is guaranteed that the object and the
184 * minor->dev pointer will stay valid! However, the device may get unplugged and
185 * unregistered while you hold the minor.
186 */
187static struct drm_minor *accel_minor_acquire(unsigned int minor_id)
188{
189	struct drm_minor *minor;
190	unsigned long flags;
191
192	spin_lock_irqsave(&accel_minor_lock, flags);
193	minor = idr_find(&accel_minors_idr, minor_id);
194	if (minor)
195		drm_dev_get(minor->dev);
196	spin_unlock_irqrestore(&accel_minor_lock, flags);
197
198	if (!minor) {
199		return ERR_PTR(-ENODEV);
200	} else if (drm_dev_is_unplugged(minor->dev)) {
201		drm_dev_put(minor->dev);
202		return ERR_PTR(-ENODEV);
203	}
204
205	return minor;
206}
207
208static void accel_minor_release(struct drm_minor *minor)
209{
210	drm_dev_put(minor->dev);
211}
212
213/**
214 * accel_open - open method for ACCEL file
215 * @inode: device inode
216 * @filp: file pointer.
217 *
218 * This function must be used by drivers as their &file_operations.open method.
219 * It looks up the correct ACCEL device and instantiates all the per-file
220 * resources for it. It also calls the &drm_driver.open driver callback.
221 *
222 * Return: 0 on success or negative errno value on failure.
223 */
224int accel_open(struct inode *inode, struct file *filp)
225{
226	struct drm_device *dev;
227	struct drm_minor *minor;
228	int retcode;
229
230	minor = accel_minor_acquire(iminor(inode));
231	if (IS_ERR(minor))
232		return PTR_ERR(minor);
233
234	dev = minor->dev;
235
236	atomic_fetch_inc(&dev->open_count);
237
238	/* share address_space across all char-devs of a single device */
239	filp->f_mapping = dev->anon_inode->i_mapping;
240
241	retcode = drm_open_helper(filp, minor);
242	if (retcode)
243		goto err_undo;
244
245	return 0;
246
247err_undo:
248	atomic_dec(&dev->open_count);
249	accel_minor_release(minor);
250	return retcode;
251}
252EXPORT_SYMBOL_GPL(accel_open);
253
254static int accel_stub_open(struct inode *inode, struct file *filp)
255{
256	const struct file_operations *new_fops;
257	struct drm_minor *minor;
258	int err;
259
260	minor = accel_minor_acquire(iminor(inode));
261	if (IS_ERR(minor))
262		return PTR_ERR(minor);
263
264	new_fops = fops_get(minor->dev->driver->fops);
265	if (!new_fops) {
266		err = -ENODEV;
267		goto out;
268	}
269
270	replace_fops(filp, new_fops);
271	if (filp->f_op->open)
272		err = filp->f_op->open(inode, filp);
273	else
274		err = 0;
275
276out:
277	accel_minor_release(minor);
278
279	return err;
280}
281
282static const struct file_operations accel_stub_fops = {
283	.owner = THIS_MODULE,
284	.open = accel_stub_open,
285	.llseek = noop_llseek,
286};
287
288void accel_core_exit(void)
289{
290	unregister_chrdev(ACCEL_MAJOR, "accel");
291	debugfs_remove(accel_debugfs_root);
292	accel_sysfs_destroy();
293	idr_destroy(&accel_minors_idr);
294}
295
296int __init accel_core_init(void)
297{
298	int ret;
299
300	idr_init(&accel_minors_idr);
301
302	ret = accel_sysfs_init();
303	if (ret < 0) {
304		DRM_ERROR("Cannot create ACCEL class: %d\n", ret);
305		goto error;
306	}
307
308	accel_debugfs_root = debugfs_create_dir("accel", NULL);
309
310	ret = register_chrdev(ACCEL_MAJOR, "accel", &accel_stub_fops);
311	if (ret < 0)
312		DRM_ERROR("Cannot register ACCEL major: %d\n", ret);
313
314error:
315	/*
316	 * Any cleanup due to errors will be done in drm_core_exit() that
317	 * will call accel_core_exit()
318	 */
319	return ret;
320}
321