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 static struct class *accel_class; 25 26 static 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 int accel_sysfs_init(void) 36 { 37 accel_class = class_create("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 46 static 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 54 static 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 76 static 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 */ 90 void 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 */ 116 void 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 */ 131 int 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 */ 150 void 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 */ 170 void 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 */ 190 static 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 } 210 211 static 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 */ 227 int 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; 249 250 err_undo: 251 atomic_dec(&dev->open_count); 252 accel_minor_release(minor); 253 return retcode; 254 } 255 EXPORT_SYMBOL_GPL(accel_open); 256 257 static 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; 278 279 out: 280 accel_minor_release(minor); 281 282 return err; 283 } 284 285 static const struct file_operations accel_stub_fops = { 286 .owner = THIS_MODULE, 287 .open = accel_stub_open, 288 .llseek = noop_llseek, 289 }; 290 291 void 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 } 298 299 int __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); 316 317 error: 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 } 324