1f6a4d894e73cf6c6604551f10f862510b0444b9
[linux-3.10.git] / drivers / s390 / block / xpram.c
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/sysdev.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  */
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  */
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  */
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  */
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  */
184 static int 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 0;
225 fail:
226         bio_io_error(bio);
227         return 0;
228 }
229
230 static int xpram_getgeo(struct block_device *bdev, struct hd_geometry *geo)
231 {
232         unsigned long size;
233
234         /*
235          * get geometry: we have to fake one...  trim the size to a
236          * multiple of 64 (32k): tell we have 16 sectors, 4 heads,
237          * whatever cylinders. Tell also that data starts at sector. 4.
238          */
239         size = (xpram_pages * 8) & ~0x3f;
240         geo->cylinders = size >> 6;
241         geo->heads = 4;
242         geo->sectors = 16;
243         geo->start = 4;
244         return 0;
245 }
246
247 static const struct block_device_operations xpram_devops =
248 {
249         .owner  = THIS_MODULE,
250         .getgeo = xpram_getgeo,
251 };
252
253 /*
254  * Setup xpram_sizes array.
255  */
256 static int __init xpram_setup_sizes(unsigned long pages)
257 {
258         unsigned long mem_needed;
259         unsigned long mem_auto;
260         unsigned long long size;
261         int mem_auto_no;
262         int i;
263
264         /* Check number of devices. */
265         if (devs <= 0 || devs > XPRAM_MAX_DEVS) {
266                 pr_err("%d is not a valid number of XPRAM devices\n",devs);
267                 return -EINVAL;
268         }
269         xpram_devs = devs;
270
271         /*
272          * Copy sizes array to xpram_sizes and align partition
273          * sizes to page boundary.
274          */
275         mem_needed = 0;
276         mem_auto_no = 0;
277         for (i = 0; i < xpram_devs; i++) {
278                 if (sizes[i]) {
279                         size = simple_strtoull(sizes[i], &sizes[i], 0);
280                         switch (sizes[i][0]) {
281                         case 'g':
282                         case 'G':
283                                 size <<= 20;
284                                 break;
285                         case 'm':
286                         case 'M':
287                                 size <<= 10;
288                         }
289                         xpram_sizes[i] = (size + 3) & -4UL;
290                 }
291                 if (xpram_sizes[i])
292                         mem_needed += xpram_sizes[i];
293                 else
294                         mem_auto_no++;
295         }
296         
297         pr_info("  number of devices (partitions): %d \n", xpram_devs);
298         for (i = 0; i < xpram_devs; i++) {
299                 if (xpram_sizes[i])
300                         pr_info("  size of partition %d: %u kB\n",
301                                 i, xpram_sizes[i]);
302                 else
303                         pr_info("  size of partition %d to be set "
304                                 "automatically\n",i);
305         }
306         pr_info("  memory needed (for sized partitions): %lu kB\n",
307                 mem_needed);
308         pr_info("  partitions to be sized automatically: %d\n",
309                 mem_auto_no);
310
311         if (mem_needed > pages * 4) {
312                 pr_err("Not enough expanded memory available\n");
313                 return -EINVAL;
314         }
315
316         /*
317          * partitioning:
318          * xpram_sizes[i] != 0; partition i has size xpram_sizes[i] kB
319          * else:             ; all partitions with zero xpram_sizes[i]
320          *                     partition equally the remaining space
321          */
322         if (mem_auto_no) {
323                 mem_auto = ((pages - mem_needed / 4) / mem_auto_no) * 4;
324                 pr_info("  automatically determined "
325                         "partition size: %lu kB\n", mem_auto);
326                 for (i = 0; i < xpram_devs; i++)
327                         if (xpram_sizes[i] == 0)
328                                 xpram_sizes[i] = mem_auto;
329         }
330         return 0;
331 }
332
333 static int __init xpram_setup_blkdev(void)
334 {
335         unsigned long offset;
336         int i, rc = -ENOMEM;
337
338         for (i = 0; i < xpram_devs; i++) {
339                 xpram_disks[i] = alloc_disk(1);
340                 if (!xpram_disks[i])
341                         goto out;
342                 xpram_queues[i] = blk_alloc_queue(GFP_KERNEL);
343                 if (!xpram_queues[i]) {
344                         put_disk(xpram_disks[i]);
345                         goto out;
346                 }
347                 blk_queue_make_request(xpram_queues[i], xpram_make_request);
348                 blk_queue_logical_block_size(xpram_queues[i], 4096);
349         }
350
351         /*
352          * Register xpram major.
353          */
354         rc = register_blkdev(XPRAM_MAJOR, XPRAM_NAME);
355         if (rc < 0)
356                 goto out;
357
358         /*
359          * Setup device structures.
360          */
361         offset = 0;
362         for (i = 0; i < xpram_devs; i++) {
363                 struct gendisk *disk = xpram_disks[i];
364
365                 xpram_devices[i].size = xpram_sizes[i] / 4;
366                 xpram_devices[i].offset = offset;
367                 offset += xpram_devices[i].size;
368                 disk->major = XPRAM_MAJOR;
369                 disk->first_minor = i;
370                 disk->fops = &xpram_devops;
371                 disk->private_data = &xpram_devices[i];
372                 disk->queue = xpram_queues[i];
373                 sprintf(disk->disk_name, "slram%d", i);
374                 set_capacity(disk, xpram_sizes[i] << 1);
375                 add_disk(disk);
376         }
377
378         return 0;
379 out:
380         while (i--) {
381                 blk_cleanup_queue(xpram_queues[i]);
382                 put_disk(xpram_disks[i]);
383         }
384         return rc;
385 }
386
387 /*
388  * Resume failed: Print error message and call panic.
389  */
390 static void xpram_resume_error(const char *message)
391 {
392         pr_err("Resuming the system failed: %s\n", message);
393         panic("xpram resume error\n");
394 }
395
396 /*
397  * Check if xpram setup changed between suspend and resume.
398  */
399 static int xpram_restore(struct device *dev)
400 {
401         if (!xpram_pages)
402                 return 0;
403         if (xpram_present() != 0)
404                 xpram_resume_error("xpram disappeared");
405         if (xpram_pages != xpram_highest_page_index() + 1)
406                 xpram_resume_error("Size of xpram changed");
407         return 0;
408 }
409
410 static const struct dev_pm_ops xpram_pm_ops = {
411         .restore        = xpram_restore,
412 };
413
414 static struct platform_driver xpram_pdrv = {
415         .driver = {
416                 .name   = XPRAM_NAME,
417                 .owner  = THIS_MODULE,
418                 .pm     = &xpram_pm_ops,
419         },
420 };
421
422 static struct platform_device *xpram_pdev;
423
424 /*
425  * Finally, the init/exit functions.
426  */
427 static void __exit xpram_exit(void)
428 {
429         int i;
430         for (i = 0; i < xpram_devs; i++) {
431                 del_gendisk(xpram_disks[i]);
432                 blk_cleanup_queue(xpram_queues[i]);
433                 put_disk(xpram_disks[i]);
434         }
435         unregister_blkdev(XPRAM_MAJOR, XPRAM_NAME);
436         platform_device_unregister(xpram_pdev);
437         platform_driver_unregister(&xpram_pdrv);
438 }
439
440 static int __init xpram_init(void)
441 {
442         int rc;
443
444         /* Find out size of expanded memory. */
445         if (xpram_present() != 0) {
446                 pr_err("No expanded memory available\n");
447                 return -ENODEV;
448         }
449         xpram_pages = xpram_highest_page_index() + 1;
450         pr_info("  %u pages expanded memory found (%lu KB).\n",
451                 xpram_pages, (unsigned long) xpram_pages*4);
452         rc = xpram_setup_sizes(xpram_pages);
453         if (rc)
454                 return rc;
455         rc = platform_driver_register(&xpram_pdrv);
456         if (rc)
457                 return rc;
458         xpram_pdev = platform_device_register_simple(XPRAM_NAME, -1, NULL, 0);
459         if (IS_ERR(xpram_pdev)) {
460                 rc = PTR_ERR(xpram_pdev);
461                 goto fail_platform_driver_unregister;
462         }
463         rc = xpram_setup_blkdev();
464         if (rc)
465                 goto fail_platform_device_unregister;
466         return 0;
467
468 fail_platform_device_unregister:
469         platform_device_unregister(xpram_pdev);
470 fail_platform_driver_unregister:
471         platform_driver_unregister(&xpram_pdrv);
472         return rc;
473 }
474
475 module_init(xpram_init);
476 module_exit(xpram_exit);