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 20 static DEFINE_SPINLOCK(accel_minor_lock); 21 static struct idr accel_minors_idr; 22 23 static struct dentry *accel_debugfs_root; 24 25 static struct device_type accel_sysfs_device_minor = { 26 .name = "accel_minor" 27 }; 28 29 static char *accel_devnode(const struct device *dev, umode_t *mode) 30 { 31 return kasprintf(GFP_KERNEL, "accel/%s", dev_name(dev)); 32 } 33 34 static const struct class accel_class = { 35 .name = "accel", 36 .devnode = accel_devnode, 37 }; 38 39 static int accel_sysfs_init(void) 40 { 41 return class_register(&accel_class); 42 } 43 44 static void accel_sysfs_destroy(void) 45 { 46 class_unregister(&accel_class); 47 } 48 49 static 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, "%s", dev->driver->name); 59 if (dev->dev) 60 seq_printf(m, " dev=%s", dev_name(dev->dev)); 61 if (master && master->unique) 62 seq_printf(m, " master=%s", master->unique); 63 if (dev->unique) 64 seq_printf(m, " unique=%s", dev->unique); 65 seq_puts(m, "\n"); 66 mutex_unlock(&dev->master_mutex); 67 68 return 0; 69 } 70 71 static 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 */ 82 void accel_debugfs_init(struct drm_device *dev) 83 { 84 drm_debugfs_dev_init(dev, 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 */ 93 void 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(accel_debugfs_list, ACCEL_DEBUGFS_ENTRIES, 100 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 */ 112 void 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 */ 127 int 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, 0, ACCEL_MAX_MINORS, GFP_NOWAIT); 134 spin_unlock_irqrestore(&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 */ 146 void 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, index); 152 spin_unlock_irqrestore(&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 */ 166 void 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, index); 172 spin_unlock_irqrestore(&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 */ 186 static 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, minor_id); 193 if (minor) 194 drm_dev_get(minor->dev); 195 spin_unlock_irqrestore(&accel_minor_lock, flags); 196 197 if (!minor) { 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); 202 } 203 204 return minor; 205 } 206 207 static void accel_minor_release(struct drm_minor *minor) 208 { 209 drm_dev_put(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 */ 223 int 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(iminor(inode)); 230 if (IS_ERR(minor)) 231 return PTR_ERR(minor); 232 233 dev = minor->dev; 234 235 atomic_fetch_inc(&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; 245 246 err_undo: 247 atomic_dec(&dev->open_count); 248 accel_minor_release(minor); 249 return retcode; 250 } 251 EXPORT_SYMBOL_GPL(accel_open); 252 253 static 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(iminor(inode)); 260 if (IS_ERR(minor)) 261 return PTR_ERR(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; 274 275 out: 276 accel_minor_release(minor); 277 278 return err; 279 } 280 281 static const struct file_operations accel_stub_fops = { 282 .owner = THIS_MODULE, 283 .open = accel_stub_open, 284 .llseek = noop_llseek, 285 }; 286 287 void accel_core_exit(void) 288 { 289 unregister_chrdev(ACCEL_MAJOR, "accel"); 290 debugfs_remove(accel_debugfs_root); 291 accel_sysfs_destroy(); 292 idr_destroy(&accel_minors_idr); 293 } 294 295 int __init accel_core_init(void) 296 { 297 int ret; 298 299 idr_init(&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("accel", NULL); 308 309 ret = register_chrdev(ACCEL_MAJOR, "accel", &accel_stub_fops); 310 if (ret < 0) 311 DRM_ERROR("Cannot register ACCEL major: %d\n", ret); 312 313 error: 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