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1da177e4 LT |
1 | /* |
2 | * Xpram.c -- the S/390 expanded memory RAM-disk | |
3 | * | |
4 | * significant parts of this code are based on | |
5 | * the sbull device driver presented in | |
6 | * A. Rubini: Linux Device Drivers | |
7 | * | |
8 | * Author of XPRAM specific coding: Reinhard Buendgen | |
9 | * buendgen@de.ibm.com | |
10 | * Rewrite for 2.5: Martin Schwidefsky <schwidefsky@de.ibm.com> | |
11 | * | |
12 | * External interfaces: | |
13 | * Interfaces to linux kernel | |
14 | * xpram_setup: read kernel parameters | |
15 | * Device specific file operations | |
16 | * xpram_iotcl | |
17 | * xpram_open | |
18 | * | |
19 | * "ad-hoc" partitioning: | |
20 | * the expanded memory can be partitioned among several devices | |
21 | * (with different minors). The partitioning set up can be | |
22 | * set by kernel or module parameters (int devs & int sizes[]) | |
23 | * | |
24 | * Potential future improvements: | |
25 | * generic hard disk support to replace ad-hoc partitioning | |
26 | */ | |
27 | ||
28 | #include <linux/module.h> | |
29 | #include <linux/moduleparam.h> | |
30 | #include <linux/ctype.h> /* isdigit, isxdigit */ | |
31 | #include <linux/errno.h> | |
32 | #include <linux/init.h> | |
33 | #include <linux/slab.h> | |
34 | #include <linux/blkdev.h> | |
35 | #include <linux/blkpg.h> | |
36 | #include <linux/hdreg.h> /* HDIO_GETGEO */ | |
37 | #include <linux/sysdev.h> | |
38 | #include <linux/bio.h> | |
39 | #include <linux/devfs_fs_kernel.h> | |
40 | #include <asm/uaccess.h> | |
41 | ||
42 | #define XPRAM_NAME "xpram" | |
43 | #define XPRAM_DEVS 1 /* one partition */ | |
44 | #define XPRAM_MAX_DEVS 32 /* maximal number of devices (partitions) */ | |
45 | ||
46 | #define PRINT_DEBUG(x...) printk(KERN_DEBUG XPRAM_NAME " debug:" x) | |
47 | #define PRINT_INFO(x...) printk(KERN_INFO XPRAM_NAME " info:" x) | |
48 | #define PRINT_WARN(x...) printk(KERN_WARNING XPRAM_NAME " warning:" x) | |
49 | #define PRINT_ERR(x...) printk(KERN_ERR XPRAM_NAME " error:" x) | |
50 | ||
51 | ||
52 | static struct sysdev_class xpram_sysclass = { | |
53 | set_kset_name("xpram"), | |
54 | }; | |
55 | ||
56 | static struct sys_device xpram_sys_device = { | |
57 | .id = 0, | |
58 | .cls = &xpram_sysclass, | |
59 | }; | |
60 | ||
61 | typedef struct { | |
62 | unsigned int size; /* size of xpram segment in pages */ | |
63 | unsigned int offset; /* start page of xpram segment */ | |
64 | } xpram_device_t; | |
65 | ||
66 | static xpram_device_t xpram_devices[XPRAM_MAX_DEVS]; | |
67 | static unsigned int xpram_sizes[XPRAM_MAX_DEVS]; | |
68 | static struct gendisk *xpram_disks[XPRAM_MAX_DEVS]; | |
69 | static unsigned int xpram_pages; | |
70 | static int xpram_devs; | |
71 | ||
72 | /* | |
73 | * Parameter parsing functions. | |
74 | */ | |
75 | static int devs = XPRAM_DEVS; | |
76 | static unsigned int sizes[XPRAM_MAX_DEVS]; | |
77 | ||
78 | module_param(devs, int, 0); | |
79 | module_param_array(sizes, int, NULL, 0); | |
80 | ||
81 | MODULE_PARM_DESC(devs, "number of devices (\"partitions\"), " \ | |
82 | "the default is " __MODULE_STRING(XPRAM_DEVS) "\n"); | |
83 | MODULE_PARM_DESC(sizes, "list of device (partition) sizes " \ | |
84 | "the defaults are 0s \n" \ | |
85 | "All devices with size 0 equally partition the " | |
86 | "remaining space on the expanded strorage not " | |
87 | "claimed by explicit sizes\n"); | |
88 | MODULE_LICENSE("GPL"); | |
89 | ||
90 | #ifndef MODULE | |
91 | /* | |
92 | * Parses the kernel parameters given in the kernel parameter line. | |
93 | * The expected format is | |
94 | * <number_of_partitions>[","<partition_size>]* | |
95 | * where | |
96 | * devices is a positive integer that initializes xpram_devs | |
97 | * each size is a non-negative integer possibly followed by a | |
98 | * magnitude (k,K,m,M,g,G), the list of sizes initialises | |
99 | * xpram_sizes | |
100 | * | |
101 | * Arguments | |
102 | * str: substring of kernel parameter line that contains xprams | |
103 | * kernel parameters. | |
104 | * | |
105 | * Result 0 on success, -EINVAL else -- only for Version > 2.3 | |
106 | * | |
107 | * Side effects | |
108 | * the global variabls devs is set to the value of | |
109 | * <number_of_partitions> and sizes[i] is set to the i-th | |
110 | * partition size (if provided). A parsing error of a value | |
111 | * results in this value being set to -EINVAL. | |
112 | */ | |
113 | static int __init xpram_setup (char *str) | |
114 | { | |
115 | char *cp; | |
116 | int i; | |
117 | ||
118 | devs = simple_strtoul(str, &cp, 10); | |
119 | if (cp <= str || devs > XPRAM_MAX_DEVS) | |
120 | return 0; | |
121 | for (i = 0; (i < devs) && (*cp++ == ','); i++) { | |
122 | sizes[i] = simple_strtoul(cp, &cp, 10); | |
123 | if (*cp == 'g' || *cp == 'G') { | |
124 | sizes[i] <<= 20; | |
125 | cp++; | |
126 | } else if (*cp == 'm' || *cp == 'M') { | |
127 | sizes[i] <<= 10; | |
128 | cp++; | |
129 | } else if (*cp == 'k' || *cp == 'K') | |
130 | cp++; | |
131 | while (isspace(*cp)) cp++; | |
132 | } | |
133 | if (*cp == ',' && i >= devs) | |
134 | PRINT_WARN("partition sizes list has too many entries.\n"); | |
135 | else if (*cp != 0) | |
136 | PRINT_WARN("ignored '%s' at end of parameter string.\n", cp); | |
137 | return 1; | |
138 | } | |
139 | ||
140 | __setup("xpram_parts=", xpram_setup); | |
141 | #endif | |
142 | ||
143 | /* | |
144 | * Copy expanded memory page (4kB) into main memory | |
145 | * Arguments | |
146 | * page_addr: address of target page | |
147 | * xpage_index: index of expandeded memory page | |
148 | * Return value | |
149 | * 0: if operation succeeds | |
150 | * -EIO: if pgin failed | |
151 | * -ENXIO: if xpram has vanished | |
152 | */ | |
153 | static int xpram_page_in (unsigned long page_addr, unsigned int xpage_index) | |
154 | { | |
155 | int cc; | |
156 | ||
157 | __asm__ __volatile__ ( | |
158 | " lhi %0,2\n" /* return unused cc 2 if pgin traps */ | |
159 | " .insn rre,0xb22e0000,%1,%2\n" /* pgin %1,%2 */ | |
160 | "0: ipm %0\n" | |
161 | " srl %0,28\n" | |
162 | "1:\n" | |
163 | #ifndef CONFIG_ARCH_S390X | |
164 | ".section __ex_table,\"a\"\n" | |
165 | " .align 4\n" | |
166 | " .long 0b,1b\n" | |
167 | ".previous" | |
168 | #else | |
169 | ".section __ex_table,\"a\"\n" | |
170 | " .align 8\n" | |
171 | " .quad 0b,1b\n" | |
172 | ".previous" | |
173 | #endif | |
174 | : "=&d" (cc) | |
175 | : "a" (__pa(page_addr)), "a" (xpage_index) | |
176 | : "cc" ); | |
177 | if (cc == 3) | |
178 | return -ENXIO; | |
179 | if (cc == 2) { | |
180 | PRINT_ERR("expanded storage lost!\n"); | |
181 | return -ENXIO; | |
182 | } | |
183 | if (cc == 1) { | |
184 | PRINT_ERR("page in failed for page index %u.\n", | |
185 | xpage_index); | |
186 | return -EIO; | |
187 | } | |
188 | return 0; | |
189 | } | |
190 | ||
191 | /* | |
192 | * Copy a 4kB page of main memory to an expanded memory page | |
193 | * Arguments | |
194 | * page_addr: address of source page | |
195 | * xpage_index: index of expandeded memory page | |
196 | * Return value | |
197 | * 0: if operation succeeds | |
198 | * -EIO: if pgout failed | |
199 | * -ENXIO: if xpram has vanished | |
200 | */ | |
201 | static long xpram_page_out (unsigned long page_addr, unsigned int xpage_index) | |
202 | { | |
203 | int cc; | |
204 | ||
205 | __asm__ __volatile__ ( | |
206 | " lhi %0,2\n" /* return unused cc 2 if pgout traps */ | |
207 | " .insn rre,0xb22f0000,%1,%2\n" /* pgout %1,%2 */ | |
208 | "0: ipm %0\n" | |
209 | " srl %0,28\n" | |
210 | "1:\n" | |
211 | #ifndef CONFIG_ARCH_S390X | |
212 | ".section __ex_table,\"a\"\n" | |
213 | " .align 4\n" | |
214 | " .long 0b,1b\n" | |
215 | ".previous" | |
216 | #else | |
217 | ".section __ex_table,\"a\"\n" | |
218 | " .align 8\n" | |
219 | " .quad 0b,1b\n" | |
220 | ".previous" | |
221 | #endif | |
222 | : "=&d" (cc) | |
223 | : "a" (__pa(page_addr)), "a" (xpage_index) | |
224 | : "cc" ); | |
225 | if (cc == 3) | |
226 | return -ENXIO; | |
227 | if (cc == 2) { | |
228 | PRINT_ERR("expanded storage lost!\n"); | |
229 | return -ENXIO; | |
230 | } | |
231 | if (cc == 1) { | |
232 | PRINT_ERR("page out failed for page index %u.\n", | |
233 | xpage_index); | |
234 | return -EIO; | |
235 | } | |
236 | return 0; | |
237 | } | |
238 | ||
239 | /* | |
240 | * Check if xpram is available. | |
241 | */ | |
242 | static int __init xpram_present(void) | |
243 | { | |
244 | unsigned long mem_page; | |
245 | int rc; | |
246 | ||
247 | mem_page = (unsigned long) __get_free_page(GFP_KERNEL); | |
248 | if (!mem_page) | |
249 | return -ENOMEM; | |
250 | rc = xpram_page_in(mem_page, 0); | |
251 | free_page(mem_page); | |
252 | return rc ? -ENXIO : 0; | |
253 | } | |
254 | ||
255 | /* | |
256 | * Return index of the last available xpram page. | |
257 | */ | |
258 | static unsigned long __init xpram_highest_page_index(void) | |
259 | { | |
260 | unsigned int page_index, add_bit; | |
261 | unsigned long mem_page; | |
262 | ||
263 | mem_page = (unsigned long) __get_free_page(GFP_KERNEL); | |
264 | if (!mem_page) | |
265 | return 0; | |
266 | ||
267 | page_index = 0; | |
268 | add_bit = 1ULL << (sizeof(unsigned int)*8 - 1); | |
269 | while (add_bit > 0) { | |
270 | if (xpram_page_in(mem_page, page_index | add_bit) == 0) | |
271 | page_index |= add_bit; | |
272 | add_bit >>= 1; | |
273 | } | |
274 | ||
275 | free_page (mem_page); | |
276 | ||
277 | return page_index; | |
278 | } | |
279 | ||
280 | /* | |
281 | * Block device make request function. | |
282 | */ | |
283 | static int xpram_make_request(request_queue_t *q, struct bio *bio) | |
284 | { | |
285 | xpram_device_t *xdev = bio->bi_bdev->bd_disk->private_data; | |
286 | struct bio_vec *bvec; | |
287 | unsigned int index; | |
288 | unsigned long page_addr; | |
289 | unsigned long bytes; | |
290 | int i; | |
291 | ||
292 | if ((bio->bi_sector & 7) != 0 || (bio->bi_size & 4095) != 0) | |
293 | /* Request is not page-aligned. */ | |
294 | goto fail; | |
295 | if ((bio->bi_size >> 12) > xdev->size) | |
296 | /* Request size is no page-aligned. */ | |
297 | goto fail; | |
298 | if ((bio->bi_sector >> 3) > 0xffffffffU - xdev->offset) | |
299 | goto fail; | |
300 | index = (bio->bi_sector >> 3) + xdev->offset; | |
301 | bio_for_each_segment(bvec, bio, i) { | |
302 | page_addr = (unsigned long) | |
303 | kmap(bvec->bv_page) + bvec->bv_offset; | |
304 | bytes = bvec->bv_len; | |
305 | if ((page_addr & 4095) != 0 || (bytes & 4095) != 0) | |
306 | /* More paranoia. */ | |
307 | goto fail; | |
308 | while (bytes > 0) { | |
309 | if (bio_data_dir(bio) == READ) { | |
310 | if (xpram_page_in(page_addr, index) != 0) | |
311 | goto fail; | |
312 | } else { | |
313 | if (xpram_page_out(page_addr, index) != 0) | |
314 | goto fail; | |
315 | } | |
316 | page_addr += 4096; | |
317 | bytes -= 4096; | |
318 | index++; | |
319 | } | |
320 | } | |
321 | set_bit(BIO_UPTODATE, &bio->bi_flags); | |
322 | bytes = bio->bi_size; | |
323 | bio->bi_size = 0; | |
324 | bio->bi_end_io(bio, bytes, 0); | |
325 | return 0; | |
326 | fail: | |
327 | bio_io_error(bio, bio->bi_size); | |
328 | return 0; | |
329 | } | |
330 | ||
331 | static int xpram_ioctl (struct inode *inode, struct file *filp, | |
332 | unsigned int cmd, unsigned long arg) | |
333 | { | |
334 | struct hd_geometry __user *geo; | |
335 | unsigned long size; | |
336 | if (cmd != HDIO_GETGEO) | |
337 | return -EINVAL; | |
338 | /* | |
339 | * get geometry: we have to fake one... trim the size to a | |
340 | * multiple of 64 (32k): tell we have 16 sectors, 4 heads, | |
341 | * whatever cylinders. Tell also that data starts at sector. 4. | |
342 | */ | |
343 | geo = (struct hd_geometry __user *) arg; | |
344 | size = (xpram_pages * 8) & ~0x3f; | |
345 | put_user(size >> 6, &geo->cylinders); | |
346 | put_user(4, &geo->heads); | |
347 | put_user(16, &geo->sectors); | |
348 | put_user(4, &geo->start); | |
349 | return 0; | |
350 | } | |
351 | ||
352 | static struct block_device_operations xpram_devops = | |
353 | { | |
354 | .owner = THIS_MODULE, | |
355 | .ioctl = xpram_ioctl, | |
356 | }; | |
357 | ||
358 | /* | |
359 | * Setup xpram_sizes array. | |
360 | */ | |
361 | static int __init xpram_setup_sizes(unsigned long pages) | |
362 | { | |
363 | unsigned long mem_needed; | |
364 | unsigned long mem_auto; | |
365 | int mem_auto_no; | |
366 | int i; | |
367 | ||
368 | /* Check number of devices. */ | |
369 | if (devs <= 0 || devs > XPRAM_MAX_DEVS) { | |
370 | PRINT_ERR("invalid number %d of devices\n",devs); | |
371 | return -EINVAL; | |
372 | } | |
373 | xpram_devs = devs; | |
374 | ||
375 | /* | |
376 | * Copy sizes array to xpram_sizes and align partition | |
377 | * sizes to page boundary. | |
378 | */ | |
379 | mem_needed = 0; | |
380 | mem_auto_no = 0; | |
381 | for (i = 0; i < xpram_devs; i++) { | |
382 | xpram_sizes[i] = (sizes[i] + 3) & -4UL; | |
383 | if (xpram_sizes[i]) | |
384 | mem_needed += xpram_sizes[i]; | |
385 | else | |
386 | mem_auto_no++; | |
387 | } | |
388 | ||
389 | PRINT_INFO(" number of devices (partitions): %d \n", xpram_devs); | |
390 | for (i = 0; i < xpram_devs; i++) { | |
391 | if (xpram_sizes[i]) | |
392 | PRINT_INFO(" size of partition %d: %u kB\n", | |
393 | i, xpram_sizes[i]); | |
394 | else | |
395 | PRINT_INFO(" size of partition %d to be set " | |
396 | "automatically\n",i); | |
397 | } | |
398 | PRINT_DEBUG(" memory needed (for sized partitions): %lu kB\n", | |
399 | mem_needed); | |
400 | PRINT_DEBUG(" partitions to be sized automatically: %d\n", | |
401 | mem_auto_no); | |
402 | ||
403 | if (mem_needed > pages * 4) { | |
404 | PRINT_ERR("Not enough expanded memory available\n"); | |
405 | return -EINVAL; | |
406 | } | |
407 | ||
408 | /* | |
409 | * partitioning: | |
410 | * xpram_sizes[i] != 0; partition i has size xpram_sizes[i] kB | |
411 | * else: ; all partitions with zero xpram_sizes[i] | |
412 | * partition equally the remaining space | |
413 | */ | |
414 | if (mem_auto_no) { | |
415 | mem_auto = ((pages - mem_needed / 4) / mem_auto_no) * 4; | |
416 | PRINT_INFO(" automatically determined " | |
417 | "partition size: %lu kB\n", mem_auto); | |
418 | for (i = 0; i < xpram_devs; i++) | |
419 | if (xpram_sizes[i] == 0) | |
420 | xpram_sizes[i] = mem_auto; | |
421 | } | |
422 | return 0; | |
423 | } | |
424 | ||
425 | static struct request_queue *xpram_queue; | |
426 | ||
427 | static int __init xpram_setup_blkdev(void) | |
428 | { | |
429 | unsigned long offset; | |
430 | int i, rc = -ENOMEM; | |
431 | ||
432 | for (i = 0; i < xpram_devs; i++) { | |
433 | struct gendisk *disk = alloc_disk(1); | |
434 | if (!disk) | |
435 | goto out; | |
436 | xpram_disks[i] = disk; | |
437 | } | |
438 | ||
439 | /* | |
440 | * Register xpram major. | |
441 | */ | |
442 | rc = register_blkdev(XPRAM_MAJOR, XPRAM_NAME); | |
443 | if (rc < 0) | |
444 | goto out; | |
445 | ||
446 | devfs_mk_dir("slram"); | |
447 | ||
448 | /* | |
449 | * Assign the other needed values: make request function, sizes and | |
450 | * hardsect size. All the minor devices feature the same value. | |
451 | */ | |
452 | xpram_queue = blk_alloc_queue(GFP_KERNEL); | |
453 | if (!xpram_queue) { | |
454 | rc = -ENOMEM; | |
455 | goto out_unreg; | |
456 | } | |
457 | blk_queue_make_request(xpram_queue, xpram_make_request); | |
458 | blk_queue_hardsect_size(xpram_queue, 4096); | |
459 | ||
460 | /* | |
461 | * Setup device structures. | |
462 | */ | |
463 | offset = 0; | |
464 | for (i = 0; i < xpram_devs; i++) { | |
465 | struct gendisk *disk = xpram_disks[i]; | |
466 | ||
467 | xpram_devices[i].size = xpram_sizes[i] / 4; | |
468 | xpram_devices[i].offset = offset; | |
469 | offset += xpram_devices[i].size; | |
470 | disk->major = XPRAM_MAJOR; | |
471 | disk->first_minor = i; | |
472 | disk->fops = &xpram_devops; | |
473 | disk->private_data = &xpram_devices[i]; | |
474 | disk->queue = xpram_queue; | |
475 | sprintf(disk->disk_name, "slram%d", i); | |
476 | sprintf(disk->devfs_name, "slram/%d", i); | |
477 | set_capacity(disk, xpram_sizes[i] << 1); | |
478 | add_disk(disk); | |
479 | } | |
480 | ||
481 | return 0; | |
482 | out_unreg: | |
483 | devfs_remove("slram"); | |
484 | unregister_blkdev(XPRAM_MAJOR, XPRAM_NAME); | |
485 | out: | |
486 | while (i--) | |
487 | put_disk(xpram_disks[i]); | |
488 | return rc; | |
489 | } | |
490 | ||
491 | /* | |
492 | * Finally, the init/exit functions. | |
493 | */ | |
494 | static void __exit xpram_exit(void) | |
495 | { | |
496 | int i; | |
497 | for (i = 0; i < xpram_devs; i++) { | |
498 | del_gendisk(xpram_disks[i]); | |
499 | put_disk(xpram_disks[i]); | |
500 | } | |
501 | unregister_blkdev(XPRAM_MAJOR, XPRAM_NAME); | |
502 | devfs_remove("slram"); | |
503 | blk_cleanup_queue(xpram_queue); | |
504 | sysdev_unregister(&xpram_sys_device); | |
505 | sysdev_class_unregister(&xpram_sysclass); | |
506 | } | |
507 | ||
508 | static int __init xpram_init(void) | |
509 | { | |
510 | int rc; | |
511 | ||
512 | /* Find out size of expanded memory. */ | |
513 | if (xpram_present() != 0) { | |
514 | PRINT_WARN("No expanded memory available\n"); | |
515 | return -ENODEV; | |
516 | } | |
517 | xpram_pages = xpram_highest_page_index(); | |
518 | PRINT_INFO(" %u pages expanded memory found (%lu KB).\n", | |
519 | xpram_pages, (unsigned long) xpram_pages*4); | |
520 | rc = xpram_setup_sizes(xpram_pages); | |
521 | if (rc) | |
522 | return rc; | |
523 | rc = sysdev_class_register(&xpram_sysclass); | |
524 | if (rc) | |
525 | return rc; | |
526 | ||
527 | rc = sysdev_register(&xpram_sys_device); | |
528 | if (rc) { | |
529 | sysdev_class_unregister(&xpram_sysclass); | |
530 | return rc; | |
531 | } | |
532 | rc = xpram_setup_blkdev(); | |
533 | if (rc) | |
534 | sysdev_unregister(&xpram_sys_device); | |
535 | return rc; | |
536 | } | |
537 | ||
538 | module_init(xpram_init); | |
539 | module_exit(xpram_exit); |