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
28struct 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
39static int simdisk_count = CONFIG_BLK_DEV_SIMDISK_COUNT;
40module_param(simdisk_count, int, S_IRUGO);
41MODULE_PARM_DESC(simdisk_count, "Number of simdisk units.");
42
43static int n_files;
44static 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
53static 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
63static const struct kernel_param_ops simdisk_param_ops_filename = {
64 .set = simdisk_param_set_filename,
65};
66module_param_cb(filename, &simdisk_param_ops_filename, &n_files, 0);
67MODULE_PARM_DESC(filename, "Backing storage filename.");
68
69static int simdisk_major = SIMDISK_MAJOR;
70
71static 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(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(lock: &dev->lock);
102}
103
104static 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
124static int simdisk_open(struct gendisk *disk, blk_mode_t mode)
125{
126 struct simdisk *dev = disk->private_data;
127
128 spin_lock(lock: &dev->lock);
129 ++dev->users;
130 spin_unlock(lock: &dev->lock);
131 return 0;
132}
133
134static void simdisk_release(struct gendisk *disk)
135{
136 struct simdisk *dev = disk->private_data;
137 spin_lock(lock: &dev->lock);
138 --dev->users;
139 spin_unlock(lock: &dev->lock);
140}
141
142static 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
149static struct simdisk *sddev;
150static struct proc_dir_entry *simdisk_procdir;
151
152static 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(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);
176out:
177 if (err)
178 kfree(objp: filename);
179 spin_unlock(lock: &dev->lock);
180
181 return err;
182}
183
184static int simdisk_detach(struct simdisk *dev)
185{
186 int err = 0;
187
188 spin_lock(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(objp: dev->filename);
202 dev->filename = NULL;
203 }
204 }
205 spin_unlock(lock: &dev->lock);
206 return err;
207}
208
209static 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(inode: file_inode(f: 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(objp: temp);
226 return len;
227 }
228 return simple_read_from_buffer(buf, size, ppos, "\n", 1);
229}
230
231static ssize_t proc_write_simdisk(struct file *file, const char __user *buf,
232 size_t count, loff_t *ppos)
233{
234 char *tmp;
235 struct simdisk *dev = pde_data(inode: file_inode(f: file));
236 int err;
237
238 if (count == 0 || count > PAGE_SIZE)
239 return -EINVAL;
240
241 tmp = memdup_user_nul(buf, count);
242 if (IS_ERR(tmp))
243 return PTR_ERR(tmp);
244
245 err = simdisk_detach(dev);
246 if (err != 0)
247 goto out_free;
248
249 if (count > 0 && tmp[count - 1] == '\n')
250 tmp[count - 1] = 0;
251
252 if (tmp[0])
253 err = simdisk_attach(dev, filename: tmp);
254
255 if (err == 0)
256 err = count;
257out_free:
258 kfree(objp: tmp);
259 return err;
260}
261
262static const struct proc_ops simdisk_proc_ops = {
263 .proc_read = proc_read_simdisk,
264 .proc_write = proc_write_simdisk,
265 .proc_lseek = default_llseek,
266};
267
268static int __init simdisk_setup(struct simdisk *dev, int which,
269 struct proc_dir_entry *procdir)
270{
271 struct queue_limits lim = {
272 .features = BLK_FEAT_ROTATIONAL,
273 };
274 char tmp[2] = { '0' + which, 0 };
275 int err;
276
277 dev->fd = -1;
278 dev->filename = NULL;
279 spin_lock_init(&dev->lock);
280 dev->users = 0;
281
282 dev->gd = blk_alloc_disk(&lim, NUMA_NO_NODE);
283 if (IS_ERR(dev->gd)) {
284 err = PTR_ERR(dev->gd);
285 goto out;
286 }
287 dev->gd->major = simdisk_major;
288 dev->gd->first_minor = which;
289 dev->gd->minors = SIMDISK_MINORS;
290 dev->gd->fops = &simdisk_ops;
291 dev->gd->private_data = dev;
292 snprintf(dev->gd->disk_name, 32, "simdisk%d", which);
293 set_capacity(dev->gd, 0);
294 err = add_disk(dev->gd);
295 if (err)
296 goto out_cleanup_disk;
297
298 dev->procfile = proc_create_data(tmp, 0644, procdir, &simdisk_proc_ops, dev);
299
300 return 0;
301
302out_cleanup_disk:
303 put_disk(dev->gd);
304out:
305 return err;
306}
307
308static int __init simdisk_init(void)
309{
310 int i;
311
312 if (register_blkdev(simdisk_major, "simdisk") < 0) {
313 pr_err("SIMDISK: register_blkdev: %d\n", simdisk_major);
314 return -EIO;
315 }
316 pr_info("SIMDISK: major: %d\n", simdisk_major);
317
318 if (n_files > simdisk_count)
319 simdisk_count = n_files;
320 if (simdisk_count > MAX_SIMDISK_COUNT)
321 simdisk_count = MAX_SIMDISK_COUNT;
322
323 sddev = kmalloc_array(simdisk_count, sizeof(*sddev), GFP_KERNEL);
324 if (sddev == NULL)
325 goto out_unregister;
326
327 simdisk_procdir = proc_mkdir("simdisk", 0);
328 if (simdisk_procdir == NULL)
329 goto out_free_unregister;
330
331 for (i = 0; i < simdisk_count; ++i) {
332 if (simdisk_setup(sddev + i, i, simdisk_procdir) == 0) {
333 if (filename[i] != NULL && filename[i][0] != 0 &&
334 (n_files == 0 || i < n_files))
335 simdisk_attach(sddev + i, filename[i]);
336 }
337 }
338
339 return 0;
340
341out_free_unregister:
342 kfree(sddev);
343out_unregister:
344 unregister_blkdev(simdisk_major, "simdisk");
345 return -ENOMEM;
346}
347module_init(simdisk_init);
348
349static void simdisk_teardown(struct simdisk *dev, int which,
350 struct proc_dir_entry *procdir)
351{
352 char tmp[2] = { '0' + which, 0 };
353
354 simdisk_detach(dev);
355 if (dev->gd) {
356 del_gendisk(gp: dev->gd);
357 put_disk(disk: dev->gd);
358 }
359 remove_proc_entry(tmp, procdir);
360}
361
362static void __exit simdisk_exit(void)
363{
364 int i;
365
366 for (i = 0; i < simdisk_count; ++i)
367 simdisk_teardown(sddev + i, i, simdisk_procdir);
368 remove_proc_entry("simdisk", 0);
369 kfree(sddev);
370 unregister_blkdev(simdisk_major, "simdisk");
371}
372module_exit(simdisk_exit);
373
374MODULE_ALIAS_BLOCKDEV_MAJOR(SIMDISK_MAJOR);
375
376MODULE_LICENSE("GPL");
377

source code of linux/arch/xtensa/platforms/iss/simdisk.c