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 gendisk *gd;
31 struct proc_dir_entry *procfile;
32 int users;
33 unsigned long size;
34 int fd;
35 };
36
37
38 static int simdisk_count = CONFIG_BLK_DEV_SIMDISK_COUNT;
39 module_param(simdisk_count, int, S_IRUGO);
40 MODULE_PARM_DESC(simdisk_count, "Number of simdisk units.");
41
42 static int n_files;
43 static const char *filename[MAX_SIMDISK_COUNT] = {
44 #ifdef CONFIG_SIMDISK0_FILENAME
45 CONFIG_SIMDISK0_FILENAME,
46 #ifdef CONFIG_SIMDISK1_FILENAME
47 CONFIG_SIMDISK1_FILENAME,
48 #endif
49 #endif
50 };
51
simdisk_param_set_filename(const char * val,const struct kernel_param * kp)52 static int simdisk_param_set_filename(const char *val,
53 const struct kernel_param *kp)
54 {
55 if (n_files < ARRAY_SIZE(filename))
56 filename[n_files++] = val;
57 else
58 return -EINVAL;
59 return 0;
60 }
61
62 static const struct kernel_param_ops simdisk_param_ops_filename = {
63 .set = simdisk_param_set_filename,
64 };
65 module_param_cb(filename, &simdisk_param_ops_filename, &n_files, 0);
66 MODULE_PARM_DESC(filename, "Backing storage filename.");
67
68 static int simdisk_major = SIMDISK_MAJOR;
69
simdisk_transfer(struct simdisk * dev,unsigned long sector,unsigned long nsect,char * buffer,int write)70 static void simdisk_transfer(struct simdisk *dev, unsigned long sector,
71 unsigned long nsect, char *buffer, int write)
72 {
73 unsigned long offset = sector << SECTOR_SHIFT;
74 unsigned long nbytes = nsect << SECTOR_SHIFT;
75
76 if (offset > dev->size || dev->size - offset < nbytes) {
77 pr_notice("Beyond-end %s (%ld %ld)\n",
78 write ? "write" : "read", offset, nbytes);
79 return;
80 }
81
82 spin_lock(&dev->lock);
83 while (nbytes > 0) {
84 unsigned long io;
85
86 simc_lseek(dev->fd, offset, SEEK_SET);
87 READ_ONCE(*buffer);
88 if (write)
89 io = simc_write(dev->fd, buffer, nbytes);
90 else
91 io = simc_read(dev->fd, buffer, nbytes);
92 if (io == -1) {
93 pr_err("SIMDISK: IO error %d\n", errno);
94 break;
95 }
96 buffer += io;
97 offset += io;
98 nbytes -= io;
99 }
100 spin_unlock(&dev->lock);
101 }
102
simdisk_submit_bio(struct bio * bio)103 static blk_qc_t simdisk_submit_bio(struct bio *bio)
104 {
105 struct simdisk *dev = bio->bi_bdev->bd_disk->private_data;
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 = kmap_atomic(bvec.bv_page) + bvec.bv_offset;
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 kunmap_atomic(buffer);
118 }
119
120 bio_endio(bio);
121 return BLK_QC_T_NONE;
122 }
123
simdisk_open(struct block_device * bdev,fmode_t mode)124 static int simdisk_open(struct block_device *bdev, fmode_t mode)
125 {
126 struct simdisk *dev = bdev->bd_disk->private_data;
127
128 spin_lock(&dev->lock);
129 ++dev->users;
130 spin_unlock(&dev->lock);
131 return 0;
132 }
133
simdisk_release(struct gendisk * disk,fmode_t mode)134 static void simdisk_release(struct gendisk *disk, fmode_t mode)
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
simdisk_attach(struct simdisk * dev,const char * filename)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
simdisk_detach(struct simdisk * dev)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
proc_read_simdisk(struct file * file,char __user * buf,size_t size,loff_t * ppos)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
proc_write_simdisk(struct file * file,const char __user * buf,size_t count,loff_t * ppos)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
simdisk_setup(struct simdisk * dev,int which,struct proc_dir_entry * procdir)264 static int __init simdisk_setup(struct simdisk *dev, int which,
265 struct proc_dir_entry *procdir)
266 {
267 char tmp[2] = { '0' + which, 0 };
268
269 dev->fd = -1;
270 dev->filename = NULL;
271 spin_lock_init(&dev->lock);
272 dev->users = 0;
273
274 dev->gd = blk_alloc_disk(NUMA_NO_NODE);
275 if (!dev->gd)
276 return -ENOMEM;
277 dev->gd->major = simdisk_major;
278 dev->gd->first_minor = which;
279 dev->gd->minors = SIMDISK_MINORS;
280 dev->gd->fops = &simdisk_ops;
281 dev->gd->private_data = dev;
282 snprintf(dev->gd->disk_name, 32, "simdisk%d", which);
283 set_capacity(dev->gd, 0);
284 add_disk(dev->gd);
285
286 dev->procfile = proc_create_data(tmp, 0644, procdir, &simdisk_proc_ops, dev);
287 return 0;
288 }
289
simdisk_init(void)290 static int __init simdisk_init(void)
291 {
292 int i;
293
294 if (register_blkdev(simdisk_major, "simdisk") < 0) {
295 pr_err("SIMDISK: register_blkdev: %d\n", simdisk_major);
296 return -EIO;
297 }
298 pr_info("SIMDISK: major: %d\n", simdisk_major);
299
300 if (n_files > simdisk_count)
301 simdisk_count = n_files;
302 if (simdisk_count > MAX_SIMDISK_COUNT)
303 simdisk_count = MAX_SIMDISK_COUNT;
304
305 sddev = kmalloc_array(simdisk_count, sizeof(*sddev), GFP_KERNEL);
306 if (sddev == NULL)
307 goto out_unregister;
308
309 simdisk_procdir = proc_mkdir("simdisk", 0);
310 if (simdisk_procdir == NULL)
311 goto out_free_unregister;
312
313 for (i = 0; i < simdisk_count; ++i) {
314 if (simdisk_setup(sddev + i, i, simdisk_procdir) == 0) {
315 if (filename[i] != NULL && filename[i][0] != 0 &&
316 (n_files == 0 || i < n_files))
317 simdisk_attach(sddev + i, filename[i]);
318 }
319 }
320
321 return 0;
322
323 out_free_unregister:
324 kfree(sddev);
325 out_unregister:
326 unregister_blkdev(simdisk_major, "simdisk");
327 return -ENOMEM;
328 }
329 module_init(simdisk_init);
330
simdisk_teardown(struct simdisk * dev,int which,struct proc_dir_entry * procdir)331 static void simdisk_teardown(struct simdisk *dev, int which,
332 struct proc_dir_entry *procdir)
333 {
334 char tmp[2] = { '0' + which, 0 };
335
336 simdisk_detach(dev);
337 if (dev->gd) {
338 del_gendisk(dev->gd);
339 blk_cleanup_disk(dev->gd);
340 }
341 remove_proc_entry(tmp, procdir);
342 }
343
simdisk_exit(void)344 static void __exit simdisk_exit(void)
345 {
346 int i;
347
348 for (i = 0; i < simdisk_count; ++i)
349 simdisk_teardown(sddev + i, i, simdisk_procdir);
350 remove_proc_entry("simdisk", 0);
351 kfree(sddev);
352 unregister_blkdev(simdisk_major, "simdisk");
353 }
354 module_exit(simdisk_exit);
355
356 MODULE_ALIAS_BLOCKDEV_MAJOR(SIMDISK_MAJOR);
357
358 MODULE_LICENSE("GPL");
359