Merge branch 'next'
[pandora-kernel.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 #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 <asm/uaccess.h>
40
41 #define XPRAM_NAME      "xpram"
42 #define XPRAM_DEVS      1       /* one partition */
43 #define XPRAM_MAX_DEVS  32      /* maximal number of devices (partitions) */
44
45 #define PRINT_DEBUG(x...)       printk(KERN_DEBUG XPRAM_NAME " debug:" x)
46 #define PRINT_INFO(x...)        printk(KERN_INFO XPRAM_NAME " info:" x)
47 #define PRINT_WARN(x...)        printk(KERN_WARNING XPRAM_NAME " warning:" x)
48 #define PRINT_ERR(x...)         printk(KERN_ERR XPRAM_NAME " error:" x)
49
50
51 typedef struct {
52         unsigned int    size;           /* size of xpram segment in pages */
53         unsigned int    offset;         /* start page of xpram segment */
54 } xpram_device_t;
55
56 static xpram_device_t xpram_devices[XPRAM_MAX_DEVS];
57 static unsigned int xpram_sizes[XPRAM_MAX_DEVS];
58 static struct gendisk *xpram_disks[XPRAM_MAX_DEVS];
59 static struct request_queue *xpram_queues[XPRAM_MAX_DEVS];
60 static unsigned int xpram_pages;
61 static int xpram_devs;
62
63 /*
64  * Parameter parsing functions.
65  */
66 static int __initdata devs = XPRAM_DEVS;
67 static char __initdata *sizes[XPRAM_MAX_DEVS];
68
69 module_param(devs, int, 0);
70 module_param_array(sizes, charp, NULL, 0);
71
72 MODULE_PARM_DESC(devs, "number of devices (\"partitions\"), " \
73                  "the default is " __MODULE_STRING(XPRAM_DEVS) "\n");
74 MODULE_PARM_DESC(sizes, "list of device (partition) sizes " \
75                  "the defaults are 0s \n" \
76                  "All devices with size 0 equally partition the "
77                  "remaining space on the expanded strorage not "
78                  "claimed by explicit sizes\n");
79 MODULE_LICENSE("GPL");
80
81 /*
82  * Copy expanded memory page (4kB) into main memory                  
83  * Arguments                                                         
84  *           page_addr:    address of target page                    
85  *           xpage_index:  index of expandeded memory page           
86  * Return value                                                      
87  *           0:            if operation succeeds
88  *           -EIO:         if pgin failed
89  *           -ENXIO:       if xpram has vanished
90  */
91 static int xpram_page_in (unsigned long page_addr, unsigned int xpage_index)
92 {
93         int cc = 2;     /* return unused cc 2 if pgin traps */
94
95         asm volatile(
96                 "       .insn   rre,0xb22e0000,%1,%2\n"  /* pgin %1,%2 */
97                 "0:     ipm     %0\n"
98                 "       srl     %0,28\n"
99                 "1:\n"
100                 EX_TABLE(0b,1b)
101                 : "+d" (cc) : "a" (__pa(page_addr)), "d" (xpage_index) : "cc");
102         if (cc == 3)
103                 return -ENXIO;
104         if (cc == 2)
105                 return -ENXIO;
106         if (cc == 1)
107                 return -EIO;
108         return 0;
109 }
110
111 /*
112  * Copy a 4kB page of main memory to an expanded memory page          
113  * Arguments                                                          
114  *           page_addr:    address of source page                     
115  *           xpage_index:  index of expandeded memory page            
116  * Return value                                                       
117  *           0:            if operation succeeds
118  *           -EIO:         if pgout failed
119  *           -ENXIO:       if xpram has vanished
120  */
121 static long xpram_page_out (unsigned long page_addr, unsigned int xpage_index)
122 {
123         int cc = 2;     /* return unused cc 2 if pgin traps */
124
125         asm volatile(
126                 "       .insn   rre,0xb22f0000,%1,%2\n"  /* pgout %1,%2 */
127                 "0:     ipm     %0\n"
128                 "       srl     %0,28\n"
129                 "1:\n"
130                 EX_TABLE(0b,1b)
131                 : "+d" (cc) : "a" (__pa(page_addr)), "d" (xpage_index) : "cc");
132         if (cc == 3)
133                 return -ENXIO;
134         if (cc == 2)
135                 return -ENXIO;
136         if (cc == 1)
137                 return -EIO;
138         return 0;
139 }
140
141 /*
142  * Check if xpram is available.
143  */
144 static int __init xpram_present(void)
145 {
146         unsigned long mem_page;
147         int rc;
148
149         mem_page = (unsigned long) __get_free_page(GFP_KERNEL);
150         if (!mem_page)
151                 return -ENOMEM;
152         rc = xpram_page_in(mem_page, 0);
153         free_page(mem_page);
154         return rc ? -ENXIO : 0;
155 }
156
157 /*
158  * Return index of the last available xpram page.
159  */
160 static unsigned long __init xpram_highest_page_index(void)
161 {
162         unsigned int page_index, add_bit;
163         unsigned long mem_page;
164
165         mem_page = (unsigned long) __get_free_page(GFP_KERNEL);
166         if (!mem_page)
167                 return 0;
168
169         page_index = 0;
170         add_bit = 1ULL << (sizeof(unsigned int)*8 - 1);
171         while (add_bit > 0) {
172                 if (xpram_page_in(mem_page, page_index | add_bit) == 0)
173                         page_index |= add_bit;
174                 add_bit >>= 1;
175         }
176
177         free_page (mem_page);
178
179         return page_index;
180 }
181
182 /*
183  * Block device make request function.
184  */
185 static int xpram_make_request(struct request_queue *q, struct bio *bio)
186 {
187         xpram_device_t *xdev = bio->bi_bdev->bd_disk->private_data;
188         struct bio_vec *bvec;
189         unsigned int index;
190         unsigned long page_addr;
191         unsigned long bytes;
192         int i;
193
194         if ((bio->bi_sector & 7) != 0 || (bio->bi_size & 4095) != 0)
195                 /* Request is not page-aligned. */
196                 goto fail;
197         if ((bio->bi_size >> 12) > xdev->size)
198                 /* Request size is no page-aligned. */
199                 goto fail;
200         if ((bio->bi_sector >> 3) > 0xffffffffU - xdev->offset)
201                 goto fail;
202         index = (bio->bi_sector >> 3) + xdev->offset;
203         bio_for_each_segment(bvec, bio, i) {
204                 page_addr = (unsigned long)
205                         kmap(bvec->bv_page) + bvec->bv_offset;
206                 bytes = bvec->bv_len;
207                 if ((page_addr & 4095) != 0 || (bytes & 4095) != 0)
208                         /* More paranoia. */
209                         goto fail;
210                 while (bytes > 0) {
211                         if (bio_data_dir(bio) == READ) {
212                                 if (xpram_page_in(page_addr, index) != 0)
213                                         goto fail;
214                         } else {
215                                 if (xpram_page_out(page_addr, index) != 0)
216                                         goto fail;
217                         }
218                         page_addr += 4096;
219                         bytes -= 4096;
220                         index++;
221                 }
222         }
223         set_bit(BIO_UPTODATE, &bio->bi_flags);
224         bio_endio(bio, 0);
225         return 0;
226 fail:
227         bio_io_error(bio);
228         return 0;
229 }
230
231 static int xpram_getgeo(struct block_device *bdev, struct hd_geometry *geo)
232 {
233         unsigned long size;
234
235         /*
236          * get geometry: we have to fake one...  trim the size to a
237          * multiple of 64 (32k): tell we have 16 sectors, 4 heads,
238          * whatever cylinders. Tell also that data starts at sector. 4.
239          */
240         size = (xpram_pages * 8) & ~0x3f;
241         geo->cylinders = size >> 6;
242         geo->heads = 4;
243         geo->sectors = 16;
244         geo->start = 4;
245         return 0;
246 }
247
248 static struct block_device_operations xpram_devops =
249 {
250         .owner  = THIS_MODULE,
251         .getgeo = xpram_getgeo,
252 };
253
254 /*
255  * Setup xpram_sizes array.
256  */
257 static int __init xpram_setup_sizes(unsigned long pages)
258 {
259         unsigned long mem_needed;
260         unsigned long mem_auto;
261         unsigned long long size;
262         int mem_auto_no;
263         int i;
264
265         /* Check number of devices. */
266         if (devs <= 0 || devs > XPRAM_MAX_DEVS) {
267                 PRINT_ERR("invalid number %d of devices\n",devs);
268                 return -EINVAL;
269         }
270         xpram_devs = devs;
271
272         /*
273          * Copy sizes array to xpram_sizes and align partition
274          * sizes to page boundary.
275          */
276         mem_needed = 0;
277         mem_auto_no = 0;
278         for (i = 0; i < xpram_devs; i++) {
279                 if (sizes[i]) {
280                         size = simple_strtoull(sizes[i], &sizes[i], 0);
281                         switch (sizes[i][0]) {
282                         case 'g':
283                         case 'G':
284                                 size <<= 20;
285                                 break;
286                         case 'm':
287                         case 'M':
288                                 size <<= 10;
289                         }
290                         xpram_sizes[i] = (size + 3) & -4UL;
291                 }
292                 if (xpram_sizes[i])
293                         mem_needed += xpram_sizes[i];
294                 else
295                         mem_auto_no++;
296         }
297         
298         PRINT_INFO("  number of devices (partitions): %d \n", xpram_devs);
299         for (i = 0; i < xpram_devs; i++) {
300                 if (xpram_sizes[i])
301                         PRINT_INFO("  size of partition %d: %u kB\n",
302                                    i, xpram_sizes[i]);
303                 else
304                         PRINT_INFO("  size of partition %d to be set "
305                                    "automatically\n",i);
306         }
307         PRINT_DEBUG("  memory needed (for sized partitions): %lu kB\n",
308                     mem_needed);
309         PRINT_DEBUG("  partitions to be sized automatically: %d\n",
310                     mem_auto_no);
311
312         if (mem_needed > pages * 4) {
313                 PRINT_ERR("Not enough expanded memory available\n");
314                 return -EINVAL;
315         }
316
317         /*
318          * partitioning:
319          * xpram_sizes[i] != 0; partition i has size xpram_sizes[i] kB
320          * else:             ; all partitions with zero xpram_sizes[i]
321          *                     partition equally the remaining space
322          */
323         if (mem_auto_no) {
324                 mem_auto = ((pages - mem_needed / 4) / mem_auto_no) * 4;
325                 PRINT_INFO("  automatically determined "
326                            "partition size: %lu kB\n", mem_auto);
327                 for (i = 0; i < xpram_devs; i++)
328                         if (xpram_sizes[i] == 0)
329                                 xpram_sizes[i] = mem_auto;
330         }
331         return 0;
332 }
333
334 static int __init xpram_setup_blkdev(void)
335 {
336         unsigned long offset;
337         int i, rc = -ENOMEM;
338
339         for (i = 0; i < xpram_devs; i++) {
340                 xpram_disks[i] = alloc_disk(1);
341                 if (!xpram_disks[i])
342                         goto out;
343                 xpram_queues[i] = blk_alloc_queue(GFP_KERNEL);
344                 if (!xpram_queues[i]) {
345                         put_disk(xpram_disks[i]);
346                         goto out;
347                 }
348                 blk_queue_make_request(xpram_queues[i], xpram_make_request);
349                 blk_queue_hardsect_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  * Finally, the init/exit functions.
390  */
391 static void __exit xpram_exit(void)
392 {
393         int i;
394         for (i = 0; i < xpram_devs; i++) {
395                 del_gendisk(xpram_disks[i]);
396                 blk_cleanup_queue(xpram_queues[i]);
397                 put_disk(xpram_disks[i]);
398         }
399         unregister_blkdev(XPRAM_MAJOR, XPRAM_NAME);
400 }
401
402 static int __init xpram_init(void)
403 {
404         int rc;
405
406         /* Find out size of expanded memory. */
407         if (xpram_present() != 0) {
408                 PRINT_WARN("No expanded memory available\n");
409                 return -ENODEV;
410         }
411         xpram_pages = xpram_highest_page_index() + 1;
412         PRINT_INFO("  %u pages expanded memory found (%lu KB).\n",
413                    xpram_pages, (unsigned long) xpram_pages*4);
414         rc = xpram_setup_sizes(xpram_pages);
415         if (rc)
416                 return rc;
417         return xpram_setup_blkdev();
418 }
419
420 module_init(xpram_init);
421 module_exit(xpram_exit);