1 /* 2 * arch/xtensa/platforms/iss/simdisk.c 3 * 4 * This file is subject to the terms and conditions of the GNU General Public 5 * License. See the file "COPYING" in the main directory of this archive 6 * for more details. 7 * 8 * Copyright (C) 2001-2013 Tensilica Inc. 9 * Authors Victor Prupis 10 */ 11 12 #include <linux/module.h> 13 #include <linux/moduleparam.h> 14 #include <linux/kernel.h> 15 #include <linux/init.h> 16 #include <linux/string.h> 17 #include <linux/string_choices.h> 18 #include <linux/blkdev.h> 19 #include <linux/bio.h> 20 #include <linux/proc_fs.h> 21 #include <linux/uaccess.h> 22 #include <platform/simcall.h> 23 24 #define SIMDISK_MAJOR 240 25 #define SIMDISK_MINORS 1 26 #define MAX_SIMDISK_COUNT 10 27 28 struct simdisk { 29 const char *filename; 30 spinlock_t lock; 31 struct gendisk *gd; 32 struct proc_dir_entry *procfile; 33 int users; 34 unsigned long size; 35 int fd; 36 }; 37 38 39 static int simdisk_count = CONFIG_BLK_DEV_SIMDISK_COUNT; 40 module_param(simdisk_count, int, S_IRUGO); 41 MODULE_PARM_DESC(simdisk_count, "Number of simdisk units."); 42 43 static int n_files; 44 static const char *filename[MAX_SIMDISK_COUNT] = { 45 #ifdef CONFIG_SIMDISK0_FILENAME 46 CONFIG_SIMDISK0_FILENAME, 47 #ifdef CONFIG_SIMDISK1_FILENAME 48 CONFIG_SIMDISK1_FILENAME, 49 #endif 50 #endif 51 }; 52 53 static int simdisk_param_set_filename(const char *val, 54 const struct kernel_param *kp) 55 { 56 if (n_files < ARRAY_SIZE(filename)) 57 filename[n_files++] = val; 58 else 59 return -EINVAL; 60 return 0; 61 } 62 63 static const struct kernel_param_ops simdisk_param_ops_filename = { 64 .set = simdisk_param_set_filename, 65 }; 66 module_param_cb(filename, &simdisk_param_ops_filename, &n_files, 0); 67 MODULE_PARM_DESC(filename, "Backing storage filename."); 68 69 static int simdisk_major = SIMDISK_MAJOR; 70 71 static void simdisk_transfer(struct simdisk *dev, unsigned long sector, 72 unsigned long nsect, char *buffer, int write) 73 { 74 unsigned long offset = sector << SECTOR_SHIFT; 75 unsigned long nbytes = nsect << SECTOR_SHIFT; 76 77 if (offset > dev->size || dev->size - offset < nbytes) { 78 pr_notice("Beyond-end %s (%ld %ld)\n", 79 str_write_read(write), offset, nbytes); 80 return; 81 } 82 83 spin_lock(&dev->lock); 84 while (nbytes > 0) { 85 unsigned long io; 86 87 simc_lseek(dev->fd, offset, SEEK_SET); 88 READ_ONCE(*buffer); 89 if (write) 90 io = simc_write(dev->fd, buffer, nbytes); 91 else 92 io = simc_read(dev->fd, buffer, nbytes); 93 if (io == -1) { 94 pr_err("SIMDISK: IO error %d\n", errno); 95 break; 96 } 97 buffer += io; 98 offset += io; 99 nbytes -= io; 100 } 101 spin_unlock(&dev->lock); 102 } 103 104 static void simdisk_submit_bio(struct bio *bio) 105 { 106 struct simdisk *dev = bio->bi_bdev->bd_disk->private_data; 107 struct bio_vec bvec; 108 struct bvec_iter iter; 109 sector_t sector = bio->bi_iter.bi_sector; 110 111 bio_for_each_segment(bvec, bio, iter) { 112 char *buffer = bvec_kmap_local(&bvec); 113 unsigned len = bvec.bv_len >> SECTOR_SHIFT; 114 115 simdisk_transfer(dev, sector, len, buffer, 116 bio_data_dir(bio) == WRITE); 117 sector += len; 118 kunmap_local(buffer); 119 } 120 121 bio_endio(bio); 122 } 123 124 static int simdisk_open(struct gendisk *disk, blk_mode_t mode) 125 { 126 struct simdisk *dev = disk->private_data; 127 128 spin_lock(&dev->lock); 129 ++dev->users; 130 spin_unlock(&dev->lock); 131 return 0; 132 } 133 134 static void simdisk_release(struct gendisk *disk) 135 { 136 struct simdisk *dev = disk->private_data; 137 spin_lock(&dev->lock); 138 --dev->users; 139 spin_unlock(&dev->lock); 140 } 141 142 static const struct block_device_operations simdisk_ops = { 143 .owner = THIS_MODULE, 144 .submit_bio = simdisk_submit_bio, 145 .open = simdisk_open, 146 .release = simdisk_release, 147 }; 148 149 static struct simdisk *sddev; 150 static struct proc_dir_entry *simdisk_procdir; 151 152 static int simdisk_attach(struct simdisk *dev, const char *filename) 153 { 154 int err = 0; 155 156 filename = kstrdup(filename, GFP_KERNEL); 157 if (filename == NULL) 158 return -ENOMEM; 159 160 spin_lock(&dev->lock); 161 162 if (dev->fd != -1) { 163 err = -EBUSY; 164 goto out; 165 } 166 dev->fd = simc_open(filename, O_RDWR, 0); 167 if (dev->fd == -1) { 168 pr_err("SIMDISK: Can't open %s: %d\n", filename, errno); 169 err = -ENODEV; 170 goto out; 171 } 172 dev->size = simc_lseek(dev->fd, 0, SEEK_END); 173 set_capacity(dev->gd, dev->size >> SECTOR_SHIFT); 174 dev->filename = filename; 175 pr_info("SIMDISK: %s=%s\n", dev->gd->disk_name, dev->filename); 176 out: 177 if (err) 178 kfree(filename); 179 spin_unlock(&dev->lock); 180 181 return err; 182 } 183 184 static int simdisk_detach(struct simdisk *dev) 185 { 186 int err = 0; 187 188 spin_lock(&dev->lock); 189 190 if (dev->users != 0) { 191 err = -EBUSY; 192 } else if (dev->fd != -1) { 193 if (simc_close(dev->fd)) { 194 pr_err("SIMDISK: error closing %s: %d\n", 195 dev->filename, errno); 196 err = -EIO; 197 } else { 198 pr_info("SIMDISK: %s detached from %s\n", 199 dev->gd->disk_name, dev->filename); 200 dev->fd = -1; 201 kfree(dev->filename); 202 dev->filename = NULL; 203 } 204 } 205 spin_unlock(&dev->lock); 206 return err; 207 } 208 209 static ssize_t proc_read_simdisk(struct file *file, char __user *buf, 210 size_t size, loff_t *ppos) 211 { 212 struct simdisk *dev = pde_data(file_inode(file)); 213 const char *s = dev->filename; 214 if (s) { 215 ssize_t len = strlen(s); 216 char *temp = kmalloc(len + 2, GFP_KERNEL); 217 218 if (!temp) 219 return -ENOMEM; 220 221 len = scnprintf(temp, len + 2, "%s\n", s); 222 len = simple_read_from_buffer(buf, size, ppos, 223 temp, len); 224 225 kfree(temp); 226 return len; 227 } 228 return simple_read_from_buffer(buf, size, ppos, "\n", 1); 229 } 230 231 static ssize_t proc_write_simdisk(struct file *file, const char __user *buf, 232 size_t count, loff_t *ppos) 233 { 234 char *tmp = memdup_user_nul(buf, count); 235 struct simdisk *dev = pde_data(file_inode(file)); 236 int err; 237 238 if (IS_ERR(tmp)) 239 return PTR_ERR(tmp); 240 241 err = simdisk_detach(dev); 242 if (err != 0) 243 goto out_free; 244 245 if (count > 0 && tmp[count - 1] == '\n') 246 tmp[count - 1] = 0; 247 248 if (tmp[0]) 249 err = simdisk_attach(dev, tmp); 250 251 if (err == 0) 252 err = count; 253 out_free: 254 kfree(tmp); 255 return err; 256 } 257 258 static const struct proc_ops simdisk_proc_ops = { 259 .proc_read = proc_read_simdisk, 260 .proc_write = proc_write_simdisk, 261 .proc_lseek = default_llseek, 262 }; 263 264 static int __init simdisk_setup(struct simdisk *dev, int which, 265 struct proc_dir_entry *procdir) 266 { 267 struct queue_limits lim = { 268 .features = BLK_FEAT_ROTATIONAL, 269 }; 270 char tmp[2] = { '0' + which, 0 }; 271 int err; 272 273 dev->fd = -1; 274 dev->filename = NULL; 275 spin_lock_init(&dev->lock); 276 dev->users = 0; 277 278 dev->gd = blk_alloc_disk(&lim, NUMA_NO_NODE); 279 if (IS_ERR(dev->gd)) { 280 err = PTR_ERR(dev->gd); 281 goto out; 282 } 283 dev->gd->major = simdisk_major; 284 dev->gd->first_minor = which; 285 dev->gd->minors = SIMDISK_MINORS; 286 dev->gd->fops = &simdisk_ops; 287 dev->gd->private_data = dev; 288 snprintf(dev->gd->disk_name, 32, "simdisk%d", which); 289 set_capacity(dev->gd, 0); 290 err = add_disk(dev->gd); 291 if (err) 292 goto out_cleanup_disk; 293 294 dev->procfile = proc_create_data(tmp, 0644, procdir, &simdisk_proc_ops, dev); 295 296 return 0; 297 298 out_cleanup_disk: 299 put_disk(dev->gd); 300 out: 301 return err; 302 } 303 304 static int __init simdisk_init(void) 305 { 306 int i; 307 308 if (register_blkdev(simdisk_major, "simdisk") < 0) { 309 pr_err("SIMDISK: register_blkdev: %d\n", simdisk_major); 310 return -EIO; 311 } 312 pr_info("SIMDISK: major: %d\n", simdisk_major); 313 314 if (n_files > simdisk_count) 315 simdisk_count = n_files; 316 if (simdisk_count > MAX_SIMDISK_COUNT) 317 simdisk_count = MAX_SIMDISK_COUNT; 318 319 sddev = kmalloc_array(simdisk_count, sizeof(*sddev), GFP_KERNEL); 320 if (sddev == NULL) 321 goto out_unregister; 322 323 simdisk_procdir = proc_mkdir("simdisk", 0); 324 if (simdisk_procdir == NULL) 325 goto out_free_unregister; 326 327 for (i = 0; i < simdisk_count; ++i) { 328 if (simdisk_setup(sddev + i, i, simdisk_procdir) == 0) { 329 if (filename[i] != NULL && filename[i][0] != 0 && 330 (n_files == 0 || i < n_files)) 331 simdisk_attach(sddev + i, filename[i]); 332 } 333 } 334 335 return 0; 336 337 out_free_unregister: 338 kfree(sddev); 339 out_unregister: 340 unregister_blkdev(simdisk_major, "simdisk"); 341 return -ENOMEM; 342 } 343 module_init(simdisk_init); 344 345 static void simdisk_teardown(struct simdisk *dev, int which, 346 struct proc_dir_entry *procdir) 347 { 348 char tmp[2] = { '0' + which, 0 }; 349 350 simdisk_detach(dev); 351 if (dev->gd) { 352 del_gendisk(dev->gd); 353 put_disk(dev->gd); 354 } 355 remove_proc_entry(tmp, procdir); 356 } 357 358 static void __exit simdisk_exit(void) 359 { 360 int i; 361 362 for (i = 0; i < simdisk_count; ++i) 363 simdisk_teardown(sddev + i, i, simdisk_procdir); 364 remove_proc_entry("simdisk", 0); 365 kfree(sddev); 366 unregister_blkdev(simdisk_major, "simdisk"); 367 } 368 module_exit(simdisk_exit); 369 370 MODULE_ALIAS_BLOCKDEV_MAJOR(SIMDISK_MAJOR); 371 372 MODULE_LICENSE("GPL"); 373