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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
28struct 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
40static int simdisk_count = CONFIG_BLK_DEV_SIMDISK_COUNT;
41module_param(simdisk_count, int, S_IRUGO);
42MODULE_PARM_DESC(simdisk_count, "Number of simdisk units.");
43
44static int n_files;
45static 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
54static 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
64static const struct kernel_param_ops simdisk_param_ops_filename = {
65 .set = simdisk_param_set_filename,
66};
67module_param_cb(filename, &simdisk_param_ops_filename, &n_files, 0);
68MODULE_PARM_DESC(filename, "Backing storage filename.");
69
70static int simdisk_major = SIMDISK_MAJOR;
71
72static 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
104static int simdisk_xfer_bio(struct simdisk *dev, struct bio *bio)
105{
106 struct bio_vec bvec;
107 struct bvec_iter iter;
108 sector_t sector = bio->bi_iter.bi_sector;
109
110 bio_for_each_segment(bvec, bio, iter) {
111 char *buffer = __bio_kmap_atomic(bio, iter);
112 unsigned len = bvec.bv_len >> SECTOR_SHIFT;
113
114 simdisk_transfer(dev, sector, len, buffer,
115 bio_data_dir(bio) == WRITE);
116 sector += len;
117 __bio_kunmap_atomic(buffer);
118 }
119 return 0;
120}
121
122static void simdisk_make_request(struct request_queue *q, struct bio *bio)
123{
124 struct simdisk *dev = q->queuedata;
125 int status = simdisk_xfer_bio(dev, bio);
126 bio_endio(bio, status);
127}
128
129
130static int simdisk_open(struct block_device *bdev, fmode_t mode)
131{
132 struct simdisk *dev = bdev->bd_disk->private_data;
133
134 spin_lock(&dev->lock);
135 if (!dev->users)
136 check_disk_change(bdev);
137 ++dev->users;
138 spin_unlock(&dev->lock);
139 return 0;
140}
141
142static void simdisk_release(struct gendisk *disk, fmode_t mode)
143{
144 struct simdisk *dev = disk->private_data;
145 spin_lock(&dev->lock);
146 --dev->users;
147 spin_unlock(&dev->lock);
148}
149
150static const struct block_device_operations simdisk_ops = {
151 .owner = THIS_MODULE,
152 .open = simdisk_open,
153 .release = simdisk_release,
154};
155
156static struct simdisk *sddev;
157static struct proc_dir_entry *simdisk_procdir;
158
159static int simdisk_attach(struct simdisk *dev, const char *filename)
160{
161 int err = 0;
162
163 filename = kstrdup(filename, GFP_KERNEL);
164 if (filename == NULL)
165 return -ENOMEM;
166
167 spin_lock(&dev->lock);
168
169 if (dev->fd != -1) {
170 err = -EBUSY;
171 goto out;
172 }
173 dev->fd = simc_open(filename, O_RDWR, 0);
174 if (dev->fd == -1) {
175 pr_err("SIMDISK: Can't open %s: %d\n", filename, errno);
176 err = -ENODEV;
177 goto out;
178 }
179 dev->size = simc_lseek(dev->fd, 0, SEEK_END);
180 set_capacity(dev->gd, dev->size >> SECTOR_SHIFT);
181 dev->filename = filename;
182 pr_info("SIMDISK: %s=%s\n", dev->gd->disk_name, dev->filename);
183out:
184 if (err)
185 kfree(filename);
186 spin_unlock(&dev->lock);
187
188 return err;
189}
190
191static int simdisk_detach(struct simdisk *dev)
192{
193 int err = 0;
194
195 spin_lock(&dev->lock);
196
197 if (dev->users != 0) {
198 err = -EBUSY;
199 } else if (dev->fd != -1) {
200 if (simc_close(dev->fd)) {
201 pr_err("SIMDISK: error closing %s: %d\n",
202 dev->filename, errno);
203 err = -EIO;
204 } else {
205 pr_info("SIMDISK: %s detached from %s\n",
206 dev->gd->disk_name, dev->filename);
207 dev->fd = -1;
208 kfree(dev->filename);
209 dev->filename = NULL;
210 }
211 }
212 spin_unlock(&dev->lock);
213 return err;
214}
215
216static ssize_t proc_read_simdisk(struct file *file, char __user *buf,
217 size_t size, loff_t *ppos)
218{
219 struct simdisk *dev = PDE_DATA(file_inode(file));
220 const char *s = dev->filename;
221 if (s) {
222 ssize_t n = simple_read_from_buffer(buf, size, ppos,
223 s, strlen(s));
224 if (n < 0)
225 return n;
226 buf += n;
227 size -= n;
228 }
229 return simple_read_from_buffer(buf, size, ppos, "\n", 1);
230}
231
232static ssize_t proc_write_simdisk(struct file *file, const char __user *buf,
233 size_t count, loff_t *ppos)
234{
235 char *tmp = kmalloc(count + 1, GFP_KERNEL);
236 struct simdisk *dev = PDE_DATA(file_inode(file));
237 int err;
238
239 if (tmp == NULL)
240 return -ENOMEM;
241 if (copy_from_user(tmp, buf, count)) {
242 err = -EFAULT;
243 goto out_free;
244 }
245
246 err = simdisk_detach(dev);
247 if (err != 0)
248 goto out_free;
249
250 if (count > 0 && tmp[count - 1] == '\n')
251 tmp[count - 1] = 0;
252 else
253 tmp[count] = 0;
254
255 if (tmp[0])
256 err = simdisk_attach(dev, tmp);
257
258 if (err == 0)
259 err = count;
260out_free:
261 kfree(tmp);
262 return err;
263}
264
265static const struct file_operations fops = {
266 .read = proc_read_simdisk,
267 .write = proc_write_simdisk,
268 .llseek = default_llseek,
269};
270
271static int __init simdisk_setup(struct simdisk *dev, int which,
272 struct proc_dir_entry *procdir)
273{
274 char tmp[2] = { '0' + which, 0 };
275
276 dev->fd = -1;
277 dev->filename = NULL;
278 spin_lock_init(&dev->lock);
279 dev->users = 0;
280
281 dev->queue = blk_alloc_queue(GFP_KERNEL);
282 if (dev->queue == NULL) {
283 pr_err("blk_alloc_queue failed\n");
284 goto out_alloc_queue;
285 }
286
287 blk_queue_make_request(dev->queue, simdisk_make_request);
288 dev->queue->queuedata = dev;
289
290 dev->gd = alloc_disk(SIMDISK_MINORS);
291 if (dev->gd == NULL) {
292 pr_err("alloc_disk failed\n");
293 goto out_alloc_disk;
294 }
295 dev->gd->major = simdisk_major;
296 dev->gd->first_minor = which;
297 dev->gd->fops = &simdisk_ops;
298 dev->gd->queue = dev->queue;
299 dev->gd->private_data = dev;
300 snprintf(dev->gd->disk_name, 32, "simdisk%d", which);
301 set_capacity(dev->gd, 0);
302 add_disk(dev->gd);
303
304 dev->procfile = proc_create_data(tmp, 0644, procdir, &fops, dev);
305 return 0;
306
307out_alloc_disk:
308 blk_cleanup_queue(dev->queue);
309 dev->queue = NULL;
310out_alloc_queue:
311 simc_close(dev->fd);
312 return -EIO;
313}
314
315static int __init simdisk_init(void)
316{
317 int i;
318
319 if (register_blkdev(simdisk_major, "simdisk") < 0) {
320 pr_err("SIMDISK: register_blkdev: %d\n", simdisk_major);
321 return -EIO;
322 }
323 pr_info("SIMDISK: major: %d\n", simdisk_major);
324
325 if (n_files > simdisk_count)
326 simdisk_count = n_files;
327 if (simdisk_count > MAX_SIMDISK_COUNT)
328 simdisk_count = MAX_SIMDISK_COUNT;
329
330 sddev = kmalloc(simdisk_count * sizeof(struct simdisk),
331 GFP_KERNEL);
332 if (sddev == NULL)
333 goto out_unregister;
334
335 simdisk_procdir = proc_mkdir("simdisk", 0);
336 if (simdisk_procdir == NULL)
337 goto out_free_unregister;
338
339 for (i = 0; i < simdisk_count; ++i) {
340 if (simdisk_setup(sddev + i, i, simdisk_procdir) == 0) {
341 if (filename[i] != NULL && filename[i][0] != 0 &&
342 (n_files == 0 || i < n_files))
343 simdisk_attach(sddev + i, filename[i]);
344 }
345 }
346
347 return 0;
348
349out_free_unregister:
350 kfree(sddev);
351out_unregister:
352 unregister_blkdev(simdisk_major, "simdisk");
353 return -ENOMEM;
354}
355module_init(simdisk_init);
356
357static void simdisk_teardown(struct simdisk *dev, int which,
358 struct proc_dir_entry *procdir)
359{
360 char tmp[2] = { '0' + which, 0 };
361
362 simdisk_detach(dev);
363 if (dev->gd)
364 del_gendisk(dev->gd);
365 if (dev->queue)
366 blk_cleanup_queue(dev->queue);
367 remove_proc_entry(tmp, procdir);
368}
369
370static void __exit simdisk_exit(void)
371{
372 int i;
373
374 for (i = 0; i < simdisk_count; ++i)
375 simdisk_teardown(sddev + i, i, simdisk_procdir);
376 remove_proc_entry("simdisk", 0);
377 kfree(sddev);
378 unregister_blkdev(simdisk_major, "simdisk");
379}
380module_exit(simdisk_exit);
381
382MODULE_ALIAS_BLOCKDEV_MAJOR(SIMDISK_MAJOR);
383
384MODULE_LICENSE("GPL");
385
