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 #define KMSG_COMPONENT "xpram"
29 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
30
31 #include <linux/module.h>
32 #include <linux/moduleparam.h>
33 #include <linux/ctype.h> /* isdigit, isxdigit */
34 #include <linux/errno.h>
35 #include <linux/init.h>
36 #include <linux/blkdev.h>
37 #include <linux/blkpg.h>
38 #include <linux/hdreg.h> /* HDIO_GETGEO */
39 #include <linux/device.h>
40 #include <linux/bio.h>
41 #include <linux/suspend.h>
42 #include <linux/platform_device.h>
43 #include <linux/gfp.h>
44 #include <asm/uaccess.h>
45
46 #define XPRAM_NAME "xpram"
47 #define XPRAM_DEVS 1 /* one partition */
48 #define XPRAM_MAX_DEVS 32 /* maximal number of devices (partitions) */
49
50 typedef struct {
51 unsigned int size; /* size of xpram segment in pages */
52 unsigned int offset; /* start page of xpram segment */
53 } xpram_device_t;
54
55 static xpram_device_t xpram_devices[XPRAM_MAX_DEVS];
56 static unsigned int xpram_sizes[XPRAM_MAX_DEVS];
57 static struct gendisk *xpram_disks[XPRAM_MAX_DEVS];
58 static struct request_queue *xpram_queues[XPRAM_MAX_DEVS];
59 static unsigned int xpram_pages;
60 static int xpram_devs;
61
62 /*
63 * Parameter parsing functions.
64 */
65 static int devs = XPRAM_DEVS;
66 static char *sizes[XPRAM_MAX_DEVS];
67
68 module_param(devs, int, 0);
69 module_param_array(sizes, charp, NULL, 0);
70
71 MODULE_PARM_DESC(devs, "number of devices (\"partitions\"), " \
72 "the default is " __MODULE_STRING(XPRAM_DEVS) "\n");
73 MODULE_PARM_DESC(sizes, "list of device (partition) sizes " \
74 "the defaults are 0s \n" \
75 "All devices with size 0 equally partition the "
76 "remaining space on the expanded strorage not "
77 "claimed by explicit sizes\n");
78 MODULE_LICENSE("GPL");
79
80 /*
81 * Copy expanded memory page (4kB) into main memory
82 * Arguments
83 * page_addr: address of target page
84 * xpage_index: index of expandeded memory page
85 * Return value
86 * 0: if operation succeeds
87 * -EIO: if pgin failed
88 * -ENXIO: if xpram has vanished
89 */
xpram_page_in(unsigned long page_addr,unsigned int xpage_index)90 static int xpram_page_in (unsigned long page_addr, unsigned int xpage_index)
91 {
92 int cc = 2; /* return unused cc 2 if pgin traps */
93
94 asm volatile(
95 " .insn rre,0xb22e0000,%1,%2\n" /* pgin %1,%2 */
96 "0: ipm %0\n"
97 " srl %0,28\n"
98 "1:\n"
99 EX_TABLE(0b,1b)
100 : "+d" (cc) : "a" (__pa(page_addr)), "d" (xpage_index) : "cc");
101 if (cc == 3)
102 return -ENXIO;
103 if (cc == 2)
104 return -ENXIO;
105 if (cc == 1)
106 return -EIO;
107 return 0;
108 }
109
110 /*
111 * Copy a 4kB page of main memory to an expanded memory page
112 * Arguments
113 * page_addr: address of source page
114 * xpage_index: index of expandeded memory page
115 * Return value
116 * 0: if operation succeeds
117 * -EIO: if pgout failed
118 * -ENXIO: if xpram has vanished
119 */
xpram_page_out(unsigned long page_addr,unsigned int xpage_index)120 static long xpram_page_out (unsigned long page_addr, unsigned int xpage_index)
121 {
122 int cc = 2; /* return unused cc 2 if pgin traps */
123
124 asm volatile(
125 " .insn rre,0xb22f0000,%1,%2\n" /* pgout %1,%2 */
126 "0: ipm %0\n"
127 " srl %0,28\n"
128 "1:\n"
129 EX_TABLE(0b,1b)
130 : "+d" (cc) : "a" (__pa(page_addr)), "d" (xpage_index) : "cc");
131 if (cc == 3)
132 return -ENXIO;
133 if (cc == 2)
134 return -ENXIO;
135 if (cc == 1)
136 return -EIO;
137 return 0;
138 }
139
140 /*
141 * Check if xpram is available.
142 */
xpram_present(void)143 static int xpram_present(void)
144 {
145 unsigned long mem_page;
146 int rc;
147
148 mem_page = (unsigned long) __get_free_page(GFP_KERNEL);
149 if (!mem_page)
150 return -ENOMEM;
151 rc = xpram_page_in(mem_page, 0);
152 free_page(mem_page);
153 return rc ? -ENXIO : 0;
154 }
155
156 /*
157 * Return index of the last available xpram page.
158 */
xpram_highest_page_index(void)159 static unsigned long xpram_highest_page_index(void)
160 {
161 unsigned int page_index, add_bit;
162 unsigned long mem_page;
163
164 mem_page = (unsigned long) __get_free_page(GFP_KERNEL);
165 if (!mem_page)
166 return 0;
167
168 page_index = 0;
169 add_bit = 1ULL << (sizeof(unsigned int)*8 - 1);
170 while (add_bit > 0) {
171 if (xpram_page_in(mem_page, page_index | add_bit) == 0)
172 page_index |= add_bit;
173 add_bit >>= 1;
174 }
175
176 free_page (mem_page);
177
178 return page_index;
179 }
180
181 /*
182 * Block device make request function.
183 */
xpram_make_request(struct request_queue * q,struct bio * bio)184 static void xpram_make_request(struct request_queue *q, struct bio *bio)
185 {
186 xpram_device_t *xdev = bio->bi_bdev->bd_disk->private_data;
187 struct bio_vec *bvec;
188 unsigned int index;
189 unsigned long page_addr;
190 unsigned long bytes;
191 int i;
192
193 if ((bio->bi_sector & 7) != 0 || (bio->bi_size & 4095) != 0)
194 /* Request is not page-aligned. */
195 goto fail;
196 if ((bio->bi_size >> 12) > xdev->size)
197 /* Request size is no page-aligned. */
198 goto fail;
199 if ((bio->bi_sector >> 3) > 0xffffffffU - xdev->offset)
200 goto fail;
201 index = (bio->bi_sector >> 3) + xdev->offset;
202 bio_for_each_segment(bvec, bio, i) {
203 page_addr = (unsigned long)
204 kmap(bvec->bv_page) + bvec->bv_offset;
205 bytes = bvec->bv_len;
206 if ((page_addr & 4095) != 0 || (bytes & 4095) != 0)
207 /* More paranoia. */
208 goto fail;
209 while (bytes > 0) {
210 if (bio_data_dir(bio) == READ) {
211 if (xpram_page_in(page_addr, index) != 0)
212 goto fail;
213 } else {
214 if (xpram_page_out(page_addr, index) != 0)
215 goto fail;
216 }
217 page_addr += 4096;
218 bytes -= 4096;
219 index++;
220 }
221 }
222 set_bit(BIO_UPTODATE, &bio->bi_flags);
223 bio_endio(bio, 0);
224 return;
225 fail:
226 bio_io_error(bio);
227 }
228
xpram_getgeo(struct block_device * bdev,struct hd_geometry * geo)229 static int xpram_getgeo(struct block_device *bdev, struct hd_geometry *geo)
230 {
231 unsigned long size;
232
233 /*
234 * get geometry: we have to fake one... trim the size to a
235 * multiple of 64 (32k): tell we have 16 sectors, 4 heads,
236 * whatever cylinders. Tell also that data starts at sector. 4.
237 */
238 size = (xpram_pages * 8) & ~0x3f;
239 geo->cylinders = size >> 6;
240 geo->heads = 4;
241 geo->sectors = 16;
242 geo->start = 4;
243 return 0;
244 }
245
246 static const struct block_device_operations xpram_devops =
247 {
248 .owner = THIS_MODULE,
249 .getgeo = xpram_getgeo,
250 };
251
252 /*
253 * Setup xpram_sizes array.
254 */
xpram_setup_sizes(unsigned long pages)255 static int __init xpram_setup_sizes(unsigned long pages)
256 {
257 unsigned long mem_needed;
258 unsigned long mem_auto;
259 unsigned long long size;
260 int mem_auto_no;
261 int i;
262
263 /* Check number of devices. */
264 if (devs <= 0 || devs > XPRAM_MAX_DEVS) {
265 pr_err("%d is not a valid number of XPRAM devices\n",devs);
266 return -EINVAL;
267 }
268 xpram_devs = devs;
269
270 /*
271 * Copy sizes array to xpram_sizes and align partition
272 * sizes to page boundary.
273 */
274 mem_needed = 0;
275 mem_auto_no = 0;
276 for (i = 0; i < xpram_devs; i++) {
277 if (sizes[i]) {
278 size = simple_strtoull(sizes[i], &sizes[i], 0);
279 switch (sizes[i][0]) {
280 case 'g':
281 case 'G':
282 size <<= 20;
283 break;
284 case 'm':
285 case 'M':
286 size <<= 10;
287 }
288 xpram_sizes[i] = (size + 3) & -4UL;
289 }
290 if (xpram_sizes[i])
291 mem_needed += xpram_sizes[i];
292 else
293 mem_auto_no++;
294 }
295
296 pr_info(" number of devices (partitions): %d \n", xpram_devs);
297 for (i = 0; i < xpram_devs; i++) {
298 if (xpram_sizes[i])
299 pr_info(" size of partition %d: %u kB\n",
300 i, xpram_sizes[i]);
301 else
302 pr_info(" size of partition %d to be set "
303 "automatically\n",i);
304 }
305 pr_info(" memory needed (for sized partitions): %lu kB\n",
306 mem_needed);
307 pr_info(" partitions to be sized automatically: %d\n",
308 mem_auto_no);
309
310 if (mem_needed > pages * 4) {
311 pr_err("Not enough expanded memory available\n");
312 return -EINVAL;
313 }
314
315 /*
316 * partitioning:
317 * xpram_sizes[i] != 0; partition i has size xpram_sizes[i] kB
318 * else: ; all partitions with zero xpram_sizes[i]
319 * partition equally the remaining space
320 */
321 if (mem_auto_no) {
322 mem_auto = ((pages - mem_needed / 4) / mem_auto_no) * 4;
323 pr_info(" automatically determined "
324 "partition size: %lu kB\n", mem_auto);
325 for (i = 0; i < xpram_devs; i++)
326 if (xpram_sizes[i] == 0)
327 xpram_sizes[i] = mem_auto;
328 }
329 return 0;
330 }
331
xpram_setup_blkdev(void)332 static int __init xpram_setup_blkdev(void)
333 {
334 unsigned long offset;
335 int i, rc = -ENOMEM;
336
337 for (i = 0; i < xpram_devs; i++) {
338 xpram_disks[i] = alloc_disk(1);
339 if (!xpram_disks[i])
340 goto out;
341 xpram_queues[i] = blk_alloc_queue(GFP_KERNEL);
342 if (!xpram_queues[i]) {
343 put_disk(xpram_disks[i]);
344 goto out;
345 }
346 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, xpram_queues[i]);
347 queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, xpram_queues[i]);
348 blk_queue_make_request(xpram_queues[i], xpram_make_request);
349 blk_queue_logical_block_size(xpram_queues[i], 4096);
350 }
351
352 /*
353 * Register xpram major.
354 */
355 rc = register_blkdev(XPRAM_MAJOR, XPRAM_NAME);
356 if (rc < 0)
357 goto out;
358
359 /*
360 * Setup device structures.
361 */
362 offset = 0;
363 for (i = 0; i < xpram_devs; i++) {
364 struct gendisk *disk = xpram_disks[i];
365
366 xpram_devices[i].size = xpram_sizes[i] / 4;
367 xpram_devices[i].offset = offset;
368 offset += xpram_devices[i].size;
369 disk->major = XPRAM_MAJOR;
370 disk->first_minor = i;
371 disk->fops = &xpram_devops;
372 disk->private_data = &xpram_devices[i];
373 disk->queue = xpram_queues[i];
374 sprintf(disk->disk_name, "slram%d", i);
375 set_capacity(disk, xpram_sizes[i] << 1);
376 add_disk(disk);
377 }
378
379 return 0;
380 out:
381 while (i--) {
382 blk_cleanup_queue(xpram_queues[i]);
383 put_disk(xpram_disks[i]);
384 }
385 return rc;
386 }
387
388 /*
389 * Resume failed: Print error message and call panic.
390 */
xpram_resume_error(const char * message)391 static void xpram_resume_error(const char *message)
392 {
393 pr_err("Resuming the system failed: %s\n", message);
394 panic("xpram resume error\n");
395 }
396
397 /*
398 * Check if xpram setup changed between suspend and resume.
399 */
xpram_restore(struct device * dev)400 static int xpram_restore(struct device *dev)
401 {
402 if (!xpram_pages)
403 return 0;
404 if (xpram_present() != 0)
405 xpram_resume_error("xpram disappeared");
406 if (xpram_pages != xpram_highest_page_index() + 1)
407 xpram_resume_error("Size of xpram changed");
408 return 0;
409 }
410
411 static const struct dev_pm_ops xpram_pm_ops = {
412 .restore = xpram_restore,
413 };
414
415 static struct platform_driver xpram_pdrv = {
416 .driver = {
417 .name = XPRAM_NAME,
418 .owner = THIS_MODULE,
419 .pm = &xpram_pm_ops,
420 },
421 };
422
423 static struct platform_device *xpram_pdev;
424
425 /*
426 * Finally, the init/exit functions.
427 */
xpram_exit(void)428 static void __exit xpram_exit(void)
429 {
430 int i;
431 for (i = 0; i < xpram_devs; i++) {
432 del_gendisk(xpram_disks[i]);
433 blk_cleanup_queue(xpram_queues[i]);
434 put_disk(xpram_disks[i]);
435 }
436 unregister_blkdev(XPRAM_MAJOR, XPRAM_NAME);
437 platform_device_unregister(xpram_pdev);
438 platform_driver_unregister(&xpram_pdrv);
439 }
440
xpram_init(void)441 static int __init xpram_init(void)
442 {
443 int rc;
444
445 /* Find out size of expanded memory. */
446 if (xpram_present() != 0) {
447 pr_err("No expanded memory available\n");
448 return -ENODEV;
449 }
450 xpram_pages = xpram_highest_page_index() + 1;
451 pr_info(" %u pages expanded memory found (%lu KB).\n",
452 xpram_pages, (unsigned long) xpram_pages*4);
453 rc = xpram_setup_sizes(xpram_pages);
454 if (rc)
455 return rc;
456 rc = platform_driver_register(&xpram_pdrv);
457 if (rc)
458 return rc;
459 xpram_pdev = platform_device_register_simple(XPRAM_NAME, -1, NULL, 0);
460 if (IS_ERR(xpram_pdev)) {
461 rc = PTR_ERR(xpram_pdev);
462 goto fail_platform_driver_unregister;
463 }
464 rc = xpram_setup_blkdev();
465 if (rc)
466 goto fail_platform_device_unregister;
467 return 0;
468
469 fail_platform_device_unregister:
470 platform_device_unregister(xpram_pdev);
471 fail_platform_driver_unregister:
472 platform_driver_unregister(&xpram_pdrv);
473 return rc;
474 }
475
476 module_init(xpram_init);
477 module_exit(xpram_exit);
478