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 21 static DEFINE_SPINLOCK(accel_minor_lock); 22 static struct idr accel_minors_idr; 23 24 static struct dentry *accel_debugfs_root; 25 26 static const struct device_type accel_sysfs_device_minor = { 27 .name = "accel_minor" 28 }; 29 30 static char *accel_devnode(const struct device *dev, umode_t *mode) 31 { 32 return kasprintf(GFP_KERNEL, "accel/%s", dev_name(dev)); 33 } 34 35 static const struct class accel_class = { 36 .name = "accel", 37 .devnode = accel_devnode, 38 }; 39 40 static int accel_sysfs_init(void) 41 { 42 return class_register(&accel_class); 43 } 44 45 static void accel_sysfs_destroy(void) 46 { 47 class_unregister(&accel_class); 48 } 49 50 static 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 72 static 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 */ 83 void 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 */ 94 void 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 */ 113 void 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 */ 128 int 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 */ 147 void 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 */ 167 void 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 */ 187 static 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 } 207 208 static 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 */ 224 int 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; 246 247 err_undo: 248 atomic_dec(&dev->open_count); 249 accel_minor_release(minor); 250 return retcode; 251 } 252 EXPORT_SYMBOL_GPL(accel_open); 253 254 static 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; 275 276 out: 277 accel_minor_release(minor); 278 279 return err; 280 } 281 282 static const struct file_operations accel_stub_fops = { 283 .owner = THIS_MODULE, 284 .open = accel_stub_open, 285 .llseek = noop_llseek, 286 }; 287 288 void 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 } 295 296 int __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); 313 314 error: 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