xref: /linux/arch/xtensa/platforms/iss/simdisk.c (revision f86fd32d) 
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_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 = 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 	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 = memdup_user_nul(buf, count);
231 	struct simdisk *dev = PDE_DATA(file_inode(file));
232 	int err;
233 
234 	if (IS_ERR(tmp))
235 		return PTR_ERR(tmp);
236 
237 	err = simdisk_detach(dev);
238 	if (err != 0)
239 		goto out_free;
240 
241 	if (count > 0 && tmp[count - 1] == '\n')
242 		tmp[count - 1] = 0;
243 
244 	if (tmp[0])
245 		err = simdisk_attach(dev, tmp);
246 
247 	if (err == 0)
248 		err = count;
249 out_free:
250 	kfree(tmp);
251 	return err;
252 }
253 
254 static const struct proc_ops simdisk_proc_ops = {
255 	.proc_read	= proc_read_simdisk,
256 	.proc_write	= proc_write_simdisk,
257 	.proc_lseek	= default_llseek,
258 };
259 
260 static int __init simdisk_setup(struct simdisk *dev, int which,
261 		struct proc_dir_entry *procdir)
262 {
263 	char tmp[2] = { '0' + which, 0 };
264 
265 	dev->fd = -1;
266 	dev->filename = NULL;
267 	spin_lock_init(&dev->lock);
268 	dev->users = 0;
269 
270 	dev->queue = blk_alloc_queue(GFP_KERNEL);
271 	if (dev->queue == NULL) {
272 		pr_err("blk_alloc_queue failed\n");
273 		goto out_alloc_queue;
274 	}
275 
276 	blk_queue_make_request(dev->queue, simdisk_make_request);
277 	dev->queue->queuedata = dev;
278 
279 	dev->gd = alloc_disk(SIMDISK_MINORS);
280 	if (dev->gd == NULL) {
281 		pr_err("alloc_disk failed\n");
282 		goto out_alloc_disk;
283 	}
284 	dev->gd->major = simdisk_major;
285 	dev->gd->first_minor = which;
286 	dev->gd->fops = &simdisk_ops;
287 	dev->gd->queue = dev->queue;
288 	dev->gd->private_data = dev;
289 	snprintf(dev->gd->disk_name, 32, "simdisk%d", which);
290 	set_capacity(dev->gd, 0);
291 	add_disk(dev->gd);
292 
293 	dev->procfile = proc_create_data(tmp, 0644, procdir, &simdisk_proc_ops, dev);
294 	return 0;
295 
296 out_alloc_disk:
297 	blk_cleanup_queue(dev->queue);
298 	dev->queue = NULL;
299 out_alloc_queue:
300 	return -ENOMEM;
301 }
302 
303 static int __init simdisk_init(void)
304 {
305 	int i;
306 
307 	if (register_blkdev(simdisk_major, "simdisk") < 0) {
308 		pr_err("SIMDISK: register_blkdev: %d\n", simdisk_major);
309 		return -EIO;
310 	}
311 	pr_info("SIMDISK: major: %d\n", simdisk_major);
312 
313 	if (n_files > simdisk_count)
314 		simdisk_count = n_files;
315 	if (simdisk_count > MAX_SIMDISK_COUNT)
316 		simdisk_count = MAX_SIMDISK_COUNT;
317 
318 	sddev = kmalloc_array(simdisk_count, sizeof(*sddev), GFP_KERNEL);
319 	if (sddev == NULL)
320 		goto out_unregister;
321 
322 	simdisk_procdir = proc_mkdir("simdisk", 0);
323 	if (simdisk_procdir == NULL)
324 		goto out_free_unregister;
325 
326 	for (i = 0; i < simdisk_count; ++i) {
327 		if (simdisk_setup(sddev + i, i, simdisk_procdir) == 0) {
328 			if (filename[i] != NULL && filename[i][0] != 0 &&
329 					(n_files == 0 || i < n_files))
330 				simdisk_attach(sddev + i, filename[i]);
331 		}
332 	}
333 
334 	return 0;
335 
336 out_free_unregister:
337 	kfree(sddev);
338 out_unregister:
339 	unregister_blkdev(simdisk_major, "simdisk");
340 	return -ENOMEM;
341 }
342 module_init(simdisk_init);
343 
344 static void simdisk_teardown(struct simdisk *dev, int which,
345 		struct proc_dir_entry *procdir)
346 {
347 	char tmp[2] = { '0' + which, 0 };
348 
349 	simdisk_detach(dev);
350 	if (dev->gd)
351 		del_gendisk(dev->gd);
352 	if (dev->queue)
353 		blk_cleanup_queue(dev->queue);
354 	remove_proc_entry(tmp, procdir);
355 }
356 
357 static void __exit simdisk_exit(void)
358 {
359 	int i;
360 
361 	for (i = 0; i < simdisk_count; ++i)
362 		simdisk_teardown(sddev + i, i, simdisk_procdir);
363 	remove_proc_entry("simdisk", 0);
364 	kfree(sddev);
365 	unregister_blkdev(simdisk_major, "simdisk");
366 }
367 module_exit(simdisk_exit);
368 
369 MODULE_ALIAS_BLOCKDEV_MAJOR(SIMDISK_MAJOR);
370 
371 MODULE_LICENSE("GPL");
372