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;
 24static struct class *accel_class;
 25
 26static 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 int accel_sysfs_init(void)
 36{
 37	accel_class = class_create(THIS_MODULE, "accel");
 38	if (IS_ERR(accel_class))
 39		return PTR_ERR(accel_class);
 40
 41	accel_class->devnode = accel_devnode;
 42
 43	return 0;
 44}
 45
 46static void accel_sysfs_destroy(void)
 47{
 48	if (IS_ERR_OR_NULL(accel_class))
 49		return;
 50	class_destroy(accel_class);
 51	accel_class = NULL;
 52}
 53
 54static int accel_name_info(struct seq_file *m, void *data)
 55{
 56	struct drm_info_node *node = (struct drm_info_node *) m->private;
 57	struct drm_minor *minor = node->minor;
 58	struct drm_device *dev = minor->dev;
 59	struct drm_master *master;
 60
 61	mutex_lock(&dev->master_mutex);
 62	master = dev->master;
 63	seq_printf(m, "%s", dev->driver->name);
 64	if (dev->dev)
 65		seq_printf(m, " dev=%s", dev_name(dev->dev));
 66	if (master && master->unique)
 67		seq_printf(m, " master=%s", master->unique);
 68	if (dev->unique)
 69		seq_printf(m, " unique=%s", dev->unique);
 70	seq_puts(m, "\n");
 71	mutex_unlock(&dev->master_mutex);
 72
 73	return 0;
 74}
 75
 76static const struct drm_info_list accel_debugfs_list[] = {
 77	{"name", accel_name_info, 0}
 78};
 79#define ACCEL_DEBUGFS_ENTRIES ARRAY_SIZE(accel_debugfs_list)
 80
 81/**
 82 * accel_debugfs_init() - Initialize debugfs for accel minor
 83 * @minor: Pointer to the drm_minor instance.
 84 * @minor_id: The minor's id
 85 *
 86 * This function initializes the drm minor's debugfs members and creates
 87 * a root directory for the minor in debugfs. It also creates common files
 88 * for accelerators and calls the driver's debugfs init callback.
 89 */
 90void accel_debugfs_init(struct drm_minor *minor, int minor_id)
 91{
 92	struct drm_device *dev = minor->dev;
 93	char name[64];
 94
 95	INIT_LIST_HEAD(&minor->debugfs_list);
 96	mutex_init(&minor->debugfs_lock);
 97	sprintf(name, "%d", minor_id);
 98	minor->debugfs_root = debugfs_create_dir(name, accel_debugfs_root);
 99
100	drm_debugfs_create_files(accel_debugfs_list, ACCEL_DEBUGFS_ENTRIES,
101				 minor->debugfs_root, minor);
102
103	if (dev->driver->debugfs_init)
104		dev->driver->debugfs_init(minor);
105}
106
107/**
108 * accel_set_device_instance_params() - Set some device parameters for accel device
109 * @kdev: Pointer to the device instance.
110 * @index: The minor's index
111 *
112 * This function creates the dev_t of the device using the accel major and
113 * the device's minor number. In addition, it sets the class and type of the
114 * device instance to the accel sysfs class and device type, respectively.
115 */
116void accel_set_device_instance_params(struct device *kdev, int index)
117{
118	kdev->devt = MKDEV(ACCEL_MAJOR, index);
119	kdev->class = accel_class;
120	kdev->type = &accel_sysfs_device_minor;
121}
122
123/**
124 * accel_minor_alloc() - Allocates a new accel minor
125 *
126 * This function access the accel minors idr and allocates from it
127 * a new id to represent a new accel minor
128 *
129 * Return: A new id on success or error code in case idr_alloc failed
130 */
131int accel_minor_alloc(void)
132{
133	unsigned long flags;
134	int r;
135
136	spin_lock_irqsave(&accel_minor_lock, flags);
137	r = idr_alloc(&accel_minors_idr, NULL, 0, ACCEL_MAX_MINORS, GFP_NOWAIT);
138	spin_unlock_irqrestore(&accel_minor_lock, flags);
139
140	return r;
141}
142
143/**
144 * accel_minor_remove() - Remove an accel minor
145 * @index: The minor id to remove.
146 *
147 * This function access the accel minors idr and removes from
148 * it the member with the id that is passed to this function.
149 */
150void accel_minor_remove(int index)
151{
152	unsigned long flags;
153
154	spin_lock_irqsave(&accel_minor_lock, flags);
155	idr_remove(&accel_minors_idr, index);
156	spin_unlock_irqrestore(&accel_minor_lock, flags);
157}
158
159/**
160 * accel_minor_replace() - Replace minor pointer in accel minors idr.
161 * @minor: Pointer to the new minor.
162 * @index: The minor id to replace.
163 *
164 * This function access the accel minors idr structure and replaces the pointer
165 * that is associated with an existing id. Because the minor pointer can be
166 * NULL, we need to explicitly pass the index.
167 *
168 * Return: 0 for success, negative value for error
169 */
170void accel_minor_replace(struct drm_minor *minor, int index)
171{
172	unsigned long flags;
173
174	spin_lock_irqsave(&accel_minor_lock, flags);
175	idr_replace(&accel_minors_idr, minor, index);
176	spin_unlock_irqrestore(&accel_minor_lock, flags);
177}
178
179/*
180 * Looks up the given minor-ID and returns the respective DRM-minor object. The
181 * refence-count of the underlying device is increased so you must release this
182 * object with accel_minor_release().
183 *
184 * The object can be only a drm_minor that represents an accel device.
185 *
186 * As long as you hold this minor, it is guaranteed that the object and the
187 * minor->dev pointer will stay valid! However, the device may get unplugged and
188 * unregistered while you hold the minor.
189 */
190static struct drm_minor *accel_minor_acquire(unsigned int minor_id)
191{
192	struct drm_minor *minor;
193	unsigned long flags;
194
195	spin_lock_irqsave(&accel_minor_lock, flags);
196	minor = idr_find(&accel_minors_idr, minor_id);
197	if (minor)
198		drm_dev_get(minor->dev);
199	spin_unlock_irqrestore(&accel_minor_lock, flags);
200
201	if (!minor) {
202		return ERR_PTR(-ENODEV);
203	} else if (drm_dev_is_unplugged(minor->dev)) {
204		drm_dev_put(minor->dev);
205		return ERR_PTR(-ENODEV);
206	}
207
208	return minor;
209}
210
211static void accel_minor_release(struct drm_minor *minor)
212{
213	drm_dev_put(minor->dev);
214}
215
216/**
217 * accel_open - open method for ACCEL file
218 * @inode: device inode
219 * @filp: file pointer.
220 *
221 * This function must be used by drivers as their &file_operations.open method.
222 * It looks up the correct ACCEL device and instantiates all the per-file
223 * resources for it. It also calls the &drm_driver.open driver callback.
224 *
225 * Return: 0 on success or negative errno value on failure.
226 */
227int accel_open(struct inode *inode, struct file *filp)
228{
229	struct drm_device *dev;
230	struct drm_minor *minor;
231	int retcode;
232
233	minor = accel_minor_acquire(iminor(inode));
234	if (IS_ERR(minor))
235		return PTR_ERR(minor);
236
237	dev = minor->dev;
238
239	atomic_fetch_inc(&dev->open_count);
240
241	/* share address_space across all char-devs of a single device */
242	filp->f_mapping = dev->anon_inode->i_mapping;
243
244	retcode = drm_open_helper(filp, minor);
245	if (retcode)
246		goto err_undo;
247
248	return 0;
249
250err_undo:
251	atomic_dec(&dev->open_count);
252	accel_minor_release(minor);
253	return retcode;
254}
255EXPORT_SYMBOL_GPL(accel_open);
256
257static int accel_stub_open(struct inode *inode, struct file *filp)
258{
259	const struct file_operations *new_fops;
260	struct drm_minor *minor;
261	int err;
262
263	minor = accel_minor_acquire(iminor(inode));
264	if (IS_ERR(minor))
265		return PTR_ERR(minor);
266
267	new_fops = fops_get(minor->dev->driver->fops);
268	if (!new_fops) {
269		err = -ENODEV;
270		goto out;
271	}
272
273	replace_fops(filp, new_fops);
274	if (filp->f_op->open)
275		err = filp->f_op->open(inode, filp);
276	else
277		err = 0;
278
279out:
280	accel_minor_release(minor);
281
282	return err;
283}
284
285static const struct file_operations accel_stub_fops = {
286	.owner = THIS_MODULE,
287	.open = accel_stub_open,
288	.llseek = noop_llseek,
289};
290
291void accel_core_exit(void)
292{
293	unregister_chrdev(ACCEL_MAJOR, "accel");
294	debugfs_remove(accel_debugfs_root);
295	accel_sysfs_destroy();
296	idr_destroy(&accel_minors_idr);
297}
298
299int __init accel_core_init(void)
300{
301	int ret;
302
303	idr_init(&accel_minors_idr);
304
305	ret = accel_sysfs_init();
306	if (ret < 0) {
307		DRM_ERROR("Cannot create ACCEL class: %d\n", ret);
308		goto error;
309	}
310
311	accel_debugfs_root = debugfs_create_dir("accel", NULL);
312
313	ret = register_chrdev(ACCEL_MAJOR, "accel", &accel_stub_fops);
314	if (ret < 0)
315		DRM_ERROR("Cannot register ACCEL major: %d\n", ret);
316
317error:
318	/*
319	 * Any cleanup due to errors will be done in drm_core_exit() that
320	 * will call accel_core_exit()
321	 */
322	return ret;
323}