arch/xtensa/platforms/iss/simdisk.c

   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/blkdev.h>
  18 #include <linux/bio.h>
  19 #include <linux/proc_fs.h>
  20 #include <asm/uaccess.h>
  21 #include <platform/simcall.h>
  22
  23 #define SIMDISK_MAJOR 240
  24 #define SECTOR_SHIFT 9
  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 request_queue *queue;
  32         struct gendisk *gd;
  33         struct proc_dir_entry *procfile;
  34         int users;
  35         unsigned long size;
  36         int fd;
  37 };
  38
  39
  40 static int simdisk_count = CONFIG_BLK_DEV_SIMDISK_COUNT;
  41 module_param(simdisk_count, int, S_IRUGO);
  42 MODULE_PARM_DESC(simdisk_count, "Number of simdisk units.");
  43
  44 static int n_files;
  45 static const char *filename[MAX_SIMDISK_COUNT] = {
  46 #ifdef CONFIG_SIMDISK0_FILENAME
  47         CONFIG_SIMDISK0_FILENAME,
  48 #ifdef CONFIG_SIMDISK1_FILENAME
  49         CONFIG_SIMDISK1_FILENAME,
  50 #endif
  51 #endif
  52 };
  53
  54 static int simdisk_param_set_filename(const char *val,
  55                 const struct kernel_param *kp)
  56 {
  57         if (n_files < ARRAY_SIZE(filename))
  58                 filename[n_files++] = val;
  59         else
  60                 return -EINVAL;
  61         return 0;
  62 }
  63
  64 static const struct kernel_param_ops simdisk_param_ops_filename = {
  65         .set = simdisk_param_set_filename,
  66 };
  67 module_param_cb(filename, &simdisk_param_ops_filename, &n_files, 0);
  68 MODULE_PARM_DESC(filename, "Backing storage filename.");
  69
  70 static int simdisk_major = SIMDISK_MAJOR;
  71
  72 static void simdisk_transfer(struct simdisk *dev, unsigned long sector,
  73                 unsigned long nsect, char *buffer, int write)
  74 {
  75         unsigned long offset = sector << SECTOR_SHIFT;
  76         unsigned long nbytes = nsect << SECTOR_SHIFT;
  77
  78         if (offset > dev->size || dev->size - offset < nbytes) {
  79                 pr_notice("Beyond-end %s (%ld %ld)\n",
  80                                 write ? "write" : "read", offset, nbytes);
  81                 return;
  82         }
  83
  84         spin_lock(&dev->lock);
  85         while (nbytes > 0) {
  86                 unsigned long io;
  87
  88                 simc_lseek(dev->fd, offset, SEEK_SET);
  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 blk_qc_t simdisk_make_request(struct request_queue *q, struct bio *bio)
 105 {
 106         struct simdisk *dev = q->queuedata;
 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 = __bio_kmap_atomic(bio, iter);
 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                 __bio_kunmap_atomic(buffer);
 119         }
 120
 121         bio_endio(bio);
 122         return BLK_QC_T_NONE;
 123 }
 124
 125 static int simdisk_open(struct block_device *bdev, fmode_t mode)
 126 {
 127         struct simdisk *dev = bdev->bd_disk->private_data;
 128
 129         spin_lock(&dev->lock);
 130         if (!dev->users)
 131                 check_disk_change(bdev);
 132         ++dev->users;
 133         spin_unlock(&dev->lock);
 134         return 0;
 135 }
 136
 137 static void simdisk_release(struct gendisk *disk, fmode_t mode)
 138 {
 139         struct simdisk *dev = disk->private_data;
 140         spin_lock(&dev->lock);
 141         --dev->users;
 142         spin_unlock(&dev->lock);
 143 }
 144
 145 static const struct block_device_operations simdisk_ops = {
 146         .owner          = THIS_MODULE,
 147         .open           = simdisk_open,
 148         .release        = simdisk_release,
 149 };
 150
 151 static struct simdisk *sddev;
 152 static struct proc_dir_entry *simdisk_procdir;
 153
 154 static int simdisk_attach(struct simdisk *dev, const char *filename)
 155 {
 156         int err = 0;
 157
 158         filename = kstrdup(filename, GFP_KERNEL);
 159         if (filename == NULL)
 160                 return -ENOMEM;
 161
 162         spin_lock(&dev->lock);
 163
 164         if (dev->fd != -1) {
 165                 err = -EBUSY;
 166                 goto out;
 167         }
 168         dev->fd = simc_open(filename, O_RDWR, 0);
 169         if (dev->fd == -1) {
 170                 pr_err("SIMDISK: Can't open %s: %d\n", filename, errno);
 171                 err = -ENODEV;
 172                 goto out;
 173         }
 174         dev->size = simc_lseek(dev->fd, 0, SEEK_END);
 175         set_capacity(dev->gd, dev->size >> SECTOR_SHIFT);
 176         dev->filename = filename;
 177         pr_info("SIMDISK: %s=%s\n", dev->gd->disk_name, dev->filename);
 178 out:
 179         if (err)
 180                 kfree(filename);
 181         spin_unlock(&dev->lock);
 182
 183         return err;
 184 }
 185
 186 static int simdisk_detach(struct simdisk *dev)
 187 {
 188         int err = 0;
 189
 190         spin_lock(&dev->lock);
 191
 192         if (dev->users != 0) {
 193                 err = -EBUSY;
 194         } else if (dev->fd != -1) {
 195                 if (simc_close(dev->fd)) {
 196                         pr_err("SIMDISK: error closing %s: %d\n",
 197                                         dev->filename, errno);
 198                         err = -EIO;
 199                 } else {
 200                         pr_info("SIMDISK: %s detached from %s\n",
 201                                         dev->gd->disk_name, dev->filename);
 202                         dev->fd = -1;
 203                         kfree(dev->filename);
 204                         dev->filename = NULL;
 205                 }
 206         }
 207         spin_unlock(&dev->lock);
 208         return err;
 209 }
 210
 211 static ssize_t proc_read_simdisk(struct file *file, char __user *buf,
 212                         size_t size, loff_t *ppos)
 213 {
 214         struct simdisk *dev = PDE_DATA(file_inode(file));
 215         const char *s = dev->filename;
 216         if (s) {
 217                 ssize_t n = simple_read_from_buffer(buf, size, ppos,
 218                                                         s, strlen(s));
 219                 if (n < 0)
 220                         return n;
 221                 buf += n;
 222                 size -= n;
 223         }
 224         return simple_read_from_buffer(buf, size, ppos, "\n", 1);
 225 }
 226
 227 static ssize_t proc_write_simdisk(struct file *file, const char __user *buf,
 228                         size_t count, loff_t *ppos)
 229 {
 230         char *tmp = kmalloc(count + 1, GFP_KERNEL);
 231         struct simdisk *dev = PDE_DATA(file_inode(file));
 232         int err;
 233
 234         if (tmp == NULL)
 235                 return -ENOMEM;
 236         if (copy_from_user(tmp, buf, count)) {
 237                 err = -EFAULT;
 238                 goto out_free;
 239         }
 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         else
 248                 tmp[count] = 0;
 249
 250         if (tmp[0])
 251                 err = simdisk_attach(dev, tmp);
 252
 253         if (err == 0)
 254                 err = count;
 255 out_free:
 256         kfree(tmp);
 257         return err;
 258 }
 259
 260 static const struct file_operations fops = {
 261         .read = proc_read_simdisk,
 262         .write = proc_write_simdisk,
 263         .llseek = default_llseek,
 264 };
 265
 266 static int __init simdisk_setup(struct simdisk *dev, int which,
 267                 struct proc_dir_entry *procdir)
 268 {
 269         char tmp[2] = { '0' + which, 0 };
 270
 271         dev->fd = -1;
 272         dev->filename = NULL;
 273         spin_lock_init(&dev->lock);
 274         dev->users = 0;
 275
 276         dev->queue = blk_alloc_queue(GFP_KERNEL);
 277         if (dev->queue == NULL) {
 278                 pr_err("blk_alloc_queue failed\n");
 279                 goto out_alloc_queue;
 280         }
 281
 282         blk_queue_make_request(dev->queue, simdisk_make_request);
 283         dev->queue->queuedata = dev;
 284
 285         dev->gd = alloc_disk(SIMDISK_MINORS);
 286         if (dev->gd == NULL) {
 287                 pr_err("alloc_disk failed\n");
 288                 goto out_alloc_disk;
 289         }
 290         dev->gd->major = simdisk_major;
 291         dev->gd->first_minor = which;
 292         dev->gd->fops = &simdisk_ops;
 293         dev->gd->queue = dev->queue;
 294         dev->gd->private_data = dev;
 295         snprintf(dev->gd->disk_name, 32, "simdisk%d", which);
 296         set_capacity(dev->gd, 0);
 297         add_disk(dev->gd);
 298
 299         dev->procfile = proc_create_data(tmp, 0644, procdir, &fops, dev);
 300         return 0;
 301
 302 out_alloc_disk:
 303         blk_cleanup_queue(dev->queue);
 304         dev->queue = NULL;
 305 out_alloc_queue:
 306         simc_close(dev->fd);
 307         return -EIO;
 308 }
 309
 310 static int __init simdisk_init(void)
 311 {
 312         int i;
 313
 314         if (register_blkdev(simdisk_major, "simdisk") < 0) {
 315                 pr_err("SIMDISK: register_blkdev: %d\n", simdisk_major);
 316                 return -EIO;
 317         }
 318         pr_info("SIMDISK: major: %d\n", simdisk_major);
 319
 320         if (n_files > simdisk_count)
 321                 simdisk_count = n_files;
 322         if (simdisk_count > MAX_SIMDISK_COUNT)
 323                 simdisk_count = MAX_SIMDISK_COUNT;
 324
 325         sddev = kmalloc(simdisk_count * sizeof(struct simdisk),
 326                         GFP_KERNEL);
 327         if (sddev == NULL)
 328                 goto out_unregister;
 329
 330         simdisk_procdir = proc_mkdir("simdisk", 0);
 331         if (simdisk_procdir == NULL)
 332                 goto out_free_unregister;
 333
 334         for (i = 0; i < simdisk_count; ++i) {
 335                 if (simdisk_setup(sddev + i, i, simdisk_procdir) == 0) {
 336                         if (filename[i] != NULL && filename[i][0] != 0 &&
 337                                         (n_files == 0 || i < n_files))
 338                                 simdisk_attach(sddev + i, filename[i]);
 339                 }
 340         }
 341
 342         return 0;
 343
 344 out_free_unregister:
 345         kfree(sddev);
 346 out_unregister:
 347         unregister_blkdev(simdisk_major, "simdisk");
 348         return -ENOMEM;
 349 }
 350 module_init(simdisk_init);
 351
 352 static void simdisk_teardown(struct simdisk *dev, int which,
 353                 struct proc_dir_entry *procdir)
 354 {
 355         char tmp[2] = { '0' + which, 0 };
 356
 357         simdisk_detach(dev);
 358         if (dev->gd)
 359                 del_gendisk(dev->gd);
 360         if (dev->queue)
 361                 blk_cleanup_queue(dev->queue);
 362         remove_proc_entry(tmp, procdir);
 363 }
 364
 365 static void __exit simdisk_exit(void)
 366 {
 367         int i;
 368
 369         for (i = 0; i < simdisk_count; ++i)
 370                 simdisk_teardown(sddev + i, i, simdisk_procdir);
 371         remove_proc_entry("simdisk", 0);
 372         kfree(sddev);
 373         unregister_blkdev(simdisk_major, "simdisk");
 374 }
 375 module_exit(simdisk_exit);
 376
 377 MODULE_ALIAS_BLOCKDEV_MAJOR(SIMDISK_MAJOR);
 378
 379 MODULE_LICENSE("GPL");