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 <linux/uaccess.h>
  21 #include <platform/simcall.h>
  22
  23 #define SIMDISK_MAJOR 240
  24 #define SIMDISK_MINORS 1
  25 #define MAX_SIMDISK_COUNT 10
  26
  27 struct simdisk {
  28         const char *filename;
  29         spinlock_t lock;
  30         struct request_queue *queue;
  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                                 write ? "write" : "read", 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 blk_qc_t simdisk_submit_bio(struct bio *bio)
 105 {
 106         struct simdisk *dev = bio->bi_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 = kmap_atomic(bvec.bv_page) + bvec.bv_offset;
 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_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         ++dev->users;
 131         spin_unlock(&dev->lock);
 132         return 0;
 133 }
 134
 135 static void simdisk_release(struct gendisk *disk, fmode_t mode)
 136 {
 137         struct simdisk *dev = disk->private_data;
 138         spin_lock(&dev->lock);
 139         --dev->users;
 140         spin_unlock(&dev->lock);
 141 }
 142
 143 static const struct block_device_operations simdisk_ops = {
 144         .owner          = THIS_MODULE,
 145         .submit_bio     = simdisk_submit_bio,
 146         .open           = simdisk_open,
 147         .release        = simdisk_release,
 148 };
 149
 150 static struct simdisk *sddev;
 151 static struct proc_dir_entry *simdisk_procdir;
 152
 153 static int simdisk_attach(struct simdisk *dev, const char *filename)
 154 {
 155         int err = 0;
 156
 157         filename = kstrdup(filename, GFP_KERNEL);
 158         if (filename == NULL)
 159                 return -ENOMEM;
 160
 161         spin_lock(&dev->lock);
 162
 163         if (dev->fd != -1) {
 164                 err = -EBUSY;
 165                 goto out;
 166         }
 167         dev->fd = simc_open(filename, O_RDWR, 0);
 168         if (dev->fd == -1) {
 169                 pr_err("SIMDISK: Can't open %s: %d\n", filename, errno);
 170                 err = -ENODEV;
 171                 goto out;
 172         }
 173         dev->size = simc_lseek(dev->fd, 0, SEEK_END);
 174         set_capacity(dev->gd, dev->size >> SECTOR_SHIFT);
 175         dev->filename = filename;
 176         pr_info("SIMDISK: %s=%s\n", dev->gd->disk_name, dev->filename);
 177 out:
 178         if (err)
 179                 kfree(filename);
 180         spin_unlock(&dev->lock);
 181
 182         return err;
 183 }
 184
 185 static int simdisk_detach(struct simdisk *dev)
 186 {
 187         int err = 0;
 188
 189         spin_lock(&dev->lock);
 190
 191         if (dev->users != 0) {
 192                 err = -EBUSY;
 193         } else if (dev->fd != -1) {
 194                 if (simc_close(dev->fd)) {
 195                         pr_err("SIMDISK: error closing %s: %d\n",
 196                                         dev->filename, errno);
 197                         err = -EIO;
 198                 } else {
 199                         pr_info("SIMDISK: %s detached from %s\n",
 200                                         dev->gd->disk_name, dev->filename);
 201                         dev->fd = -1;
 202                         kfree(dev->filename);
 203                         dev->filename = NULL;
 204                 }
 205         }
 206         spin_unlock(&dev->lock);
 207         return err;
 208 }
 209
 210 static ssize_t proc_read_simdisk(struct file *file, char __user *buf,
 211                         size_t size, loff_t *ppos)
 212 {
 213         struct simdisk *dev = PDE_DATA(file_inode(file));
 214         const char *s = dev->filename;
 215         if (s) {
 216                 ssize_t n = simple_read_from_buffer(buf, size, ppos,
 217                                                         s, strlen(s));
 218                 if (n < 0)
 219                         return n;
 220                 buf += n;
 221                 size -= n;
 222         }
 223         return simple_read_from_buffer(buf, size, ppos, "\n", 1);
 224 }
 225
 226 static ssize_t proc_write_simdisk(struct file *file, const char __user *buf,
 227                         size_t count, loff_t *ppos)
 228 {
 229         char *tmp = memdup_user_nul(buf, count);
 230         struct simdisk *dev = PDE_DATA(file_inode(file));
 231         int err;
 232
 233         if (IS_ERR(tmp))
 234                 return PTR_ERR(tmp);
 235
 236         err = simdisk_detach(dev);
 237         if (err != 0)
 238                 goto out_free;
 239
 240         if (count > 0 && tmp[count - 1] == '\n')
 241                 tmp[count - 1] = 0;
 242
 243         if (tmp[0])
 244                 err = simdisk_attach(dev, tmp);
 245
 246         if (err == 0)
 247                 err = count;
 248 out_free:
 249         kfree(tmp);
 250         return err;
 251 }
 252
 253 static const struct proc_ops simdisk_proc_ops = {
 254         .proc_read      = proc_read_simdisk,
 255         .proc_write     = proc_write_simdisk,
 256         .proc_lseek     = default_llseek,
 257 };
 258
 259 static int __init simdisk_setup(struct simdisk *dev, int which,
 260                 struct proc_dir_entry *procdir)
 261 {
 262         char tmp[2] = { '0' + which, 0 };
 263
 264         dev->fd = -1;
 265         dev->filename = NULL;
 266         spin_lock_init(&dev->lock);
 267         dev->users = 0;
 268
 269         dev->queue = blk_alloc_queue(NUMA_NO_NODE);
 270         if (dev->queue == NULL) {
 271                 pr_err("blk_alloc_queue failed\n");
 272                 goto out_alloc_queue;
 273         }
 274
 275         dev->gd = alloc_disk(SIMDISK_MINORS);
 276         if (dev->gd == NULL) {
 277                 pr_err("alloc_disk failed\n");
 278                 goto out_alloc_disk;
 279         }
 280         dev->gd->major = simdisk_major;
 281         dev->gd->first_minor = which;
 282         dev->gd->fops = &simdisk_ops;
 283         dev->gd->queue = dev->queue;
 284         dev->gd->private_data = dev;
 285         snprintf(dev->gd->disk_name, 32, "simdisk%d", which);
 286         set_capacity(dev->gd, 0);
 287         add_disk(dev->gd);
 288
 289         dev->procfile = proc_create_data(tmp, 0644, procdir, &simdisk_proc_ops, dev);
 290         return 0;
 291
 292 out_alloc_disk:
 293         blk_cleanup_queue(dev->queue);
 294         dev->queue = NULL;
 295 out_alloc_queue:
 296         return -ENOMEM;
 297 }
 298
 299 static int __init simdisk_init(void)
 300 {
 301         int i;
 302
 303         if (register_blkdev(simdisk_major, "simdisk") < 0) {
 304                 pr_err("SIMDISK: register_blkdev: %d\n", simdisk_major);
 305                 return -EIO;
 306         }
 307         pr_info("SIMDISK: major: %d\n", simdisk_major);
 308
 309         if (n_files > simdisk_count)
 310                 simdisk_count = n_files;
 311         if (simdisk_count > MAX_SIMDISK_COUNT)
 312                 simdisk_count = MAX_SIMDISK_COUNT;
 313
 314         sddev = kmalloc_array(simdisk_count, sizeof(*sddev), GFP_KERNEL);
 315         if (sddev == NULL)
 316                 goto out_unregister;
 317
 318         simdisk_procdir = proc_mkdir("simdisk", 0);
 319         if (simdisk_procdir == NULL)
 320                 goto out_free_unregister;
 321
 322         for (i = 0; i < simdisk_count; ++i) {
 323                 if (simdisk_setup(sddev + i, i, simdisk_procdir) == 0) {
 324                         if (filename[i] != NULL && filename[i][0] != 0 &&
 325                                         (n_files == 0 || i < n_files))
 326                                 simdisk_attach(sddev + i, filename[i]);
 327                 }
 328         }
 329
 330         return 0;
 331
 332 out_free_unregister:
 333         kfree(sddev);
 334 out_unregister:
 335         unregister_blkdev(simdisk_major, "simdisk");
 336         return -ENOMEM;
 337 }
 338 module_init(simdisk_init);
 339
 340 static void simdisk_teardown(struct simdisk *dev, int which,
 341                 struct proc_dir_entry *procdir)
 342 {
 343         char tmp[2] = { '0' + which, 0 };
 344
 345         simdisk_detach(dev);
 346         if (dev->gd)
 347                 del_gendisk(dev->gd);
 348         if (dev->queue)
 349                 blk_cleanup_queue(dev->queue);
 350         remove_proc_entry(tmp, procdir);
 351 }
 352
 353 static void __exit simdisk_exit(void)
 354 {
 355         int i;
 356
 357         for (i = 0; i < simdisk_count; ++i)
 358                 simdisk_teardown(sddev + i, i, simdisk_procdir);
 359         remove_proc_entry("simdisk", 0);
 360         kfree(sddev);
 361         unregister_blkdev(simdisk_major, "simdisk");
 362 }
 363 module_exit(simdisk_exit);
 364
 365 MODULE_ALIAS_BLOCKDEV_MAJOR(SIMDISK_MAJOR);
 366
 367 MODULE_LICENSE("GPL");