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_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 = 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");
368