2 * Xpram.c -- the S/390 expanded memory RAM-disk
4 * significant parts of this code are based on
5 * the sbull device driver presented in
6 * A. Rubini: Linux Device Drivers
8 * Author of XPRAM specific coding: Reinhard Buendgen
10 * Rewrite for 2.5: Martin Schwidefsky <schwidefsky@de.ibm.com>
12 * External interfaces:
13 * Interfaces to linux kernel
14 * xpram_setup: read kernel parameters
15 * Device specific file operations
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[])
24 * Potential future improvements:
25 * generic hard disk support to replace ad-hoc partitioning
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>
41 #define XPRAM_NAME "xpram"
42 #define XPRAM_DEVS 1 /* one partition */
43 #define XPRAM_MAX_DEVS 32 /* maximal number of devices (partitions) */
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)
52 unsigned int size
; /* size of xpram segment in pages */
53 unsigned int offset
; /* start page of xpram segment */
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 unsigned int xpram_pages
;
60 static int xpram_devs
;
63 * Parameter parsing functions.
65 static int __initdata devs
= XPRAM_DEVS
;
66 static char __initdata
*sizes
[XPRAM_MAX_DEVS
];
68 module_param(devs
, int, 0);
69 module_param_array(sizes
, charp
, NULL
, 0);
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");
81 * Copy expanded memory page (4kB) into main memory
83 * page_addr: address of target page
84 * xpage_index: index of expandeded memory page
86 * 0: if operation succeeds
87 * -EIO: if pgin failed
88 * -ENXIO: if xpram has vanished
90 static int xpram_page_in (unsigned long page_addr
, unsigned int xpage_index
)
94 __asm__
__volatile__ (
95 " lhi %0,2\n" /* return unused cc 2 if pgin traps */
96 " .insn rre,0xb22e0000,%1,%2\n" /* pgin %1,%2 */
101 ".section __ex_table,\"a\"\n"
106 ".section __ex_table,\"a\"\n"
112 : "a" (__pa(page_addr
)), "a" (xpage_index
)
117 PRINT_ERR("expanded storage lost!\n");
121 PRINT_ERR("page in failed for page index %u.\n",
129 * Copy a 4kB page of main memory to an expanded memory page
131 * page_addr: address of source page
132 * xpage_index: index of expandeded memory page
134 * 0: if operation succeeds
135 * -EIO: if pgout failed
136 * -ENXIO: if xpram has vanished
138 static long xpram_page_out (unsigned long page_addr
, unsigned int xpage_index
)
142 __asm__
__volatile__ (
143 " lhi %0,2\n" /* return unused cc 2 if pgout traps */
144 " .insn rre,0xb22f0000,%1,%2\n" /* pgout %1,%2 */
149 ".section __ex_table,\"a\"\n"
154 ".section __ex_table,\"a\"\n"
160 : "a" (__pa(page_addr
)), "a" (xpage_index
)
165 PRINT_ERR("expanded storage lost!\n");
169 PRINT_ERR("page out failed for page index %u.\n",
177 * Check if xpram is available.
179 static int __init
xpram_present(void)
181 unsigned long mem_page
;
184 mem_page
= (unsigned long) __get_free_page(GFP_KERNEL
);
187 rc
= xpram_page_in(mem_page
, 0);
189 return rc
? -ENXIO
: 0;
193 * Return index of the last available xpram page.
195 static unsigned long __init
xpram_highest_page_index(void)
197 unsigned int page_index
, add_bit
;
198 unsigned long mem_page
;
200 mem_page
= (unsigned long) __get_free_page(GFP_KERNEL
);
205 add_bit
= 1ULL << (sizeof(unsigned int)*8 - 1);
206 while (add_bit
> 0) {
207 if (xpram_page_in(mem_page
, page_index
| add_bit
) == 0)
208 page_index
|= add_bit
;
212 free_page (mem_page
);
218 * Block device make request function.
220 static int xpram_make_request(request_queue_t
*q
, struct bio
*bio
)
222 xpram_device_t
*xdev
= bio
->bi_bdev
->bd_disk
->private_data
;
223 struct bio_vec
*bvec
;
225 unsigned long page_addr
;
229 if ((bio
->bi_sector
& 7) != 0 || (bio
->bi_size
& 4095) != 0)
230 /* Request is not page-aligned. */
232 if ((bio
->bi_size
>> 12) > xdev
->size
)
233 /* Request size is no page-aligned. */
235 if ((bio
->bi_sector
>> 3) > 0xffffffffU
- xdev
->offset
)
237 index
= (bio
->bi_sector
>> 3) + xdev
->offset
;
238 bio_for_each_segment(bvec
, bio
, i
) {
239 page_addr
= (unsigned long)
240 kmap(bvec
->bv_page
) + bvec
->bv_offset
;
241 bytes
= bvec
->bv_len
;
242 if ((page_addr
& 4095) != 0 || (bytes
& 4095) != 0)
246 if (bio_data_dir(bio
) == READ
) {
247 if (xpram_page_in(page_addr
, index
) != 0)
250 if (xpram_page_out(page_addr
, index
) != 0)
258 set_bit(BIO_UPTODATE
, &bio
->bi_flags
);
259 bytes
= bio
->bi_size
;
261 bio
->bi_end_io(bio
, bytes
, 0);
264 bio_io_error(bio
, bio
->bi_size
);
268 static int xpram_getgeo(struct block_device
*bdev
, struct hd_geometry
*geo
)
273 * get geometry: we have to fake one... trim the size to a
274 * multiple of 64 (32k): tell we have 16 sectors, 4 heads,
275 * whatever cylinders. Tell also that data starts at sector. 4.
277 size
= (xpram_pages
* 8) & ~0x3f;
278 geo
->cylinders
= size
>> 6;
285 static struct block_device_operations xpram_devops
=
287 .owner
= THIS_MODULE
,
288 .getgeo
= xpram_getgeo
,
292 * Setup xpram_sizes array.
294 static int __init
xpram_setup_sizes(unsigned long pages
)
296 unsigned long mem_needed
;
297 unsigned long mem_auto
;
298 unsigned long long size
;
302 /* Check number of devices. */
303 if (devs
<= 0 || devs
> XPRAM_MAX_DEVS
) {
304 PRINT_ERR("invalid number %d of devices\n",devs
);
310 * Copy sizes array to xpram_sizes and align partition
311 * sizes to page boundary.
315 for (i
= 0; i
< xpram_devs
; i
++) {
317 size
= simple_strtoull(sizes
[i
], &sizes
[i
], 0);
318 switch (sizes
[i
][0]) {
327 xpram_sizes
[i
] = (size
+ 3) & -4UL;
330 mem_needed
+= xpram_sizes
[i
];
335 PRINT_INFO(" number of devices (partitions): %d \n", xpram_devs
);
336 for (i
= 0; i
< xpram_devs
; i
++) {
338 PRINT_INFO(" size of partition %d: %u kB\n",
341 PRINT_INFO(" size of partition %d to be set "
342 "automatically\n",i
);
344 PRINT_DEBUG(" memory needed (for sized partitions): %lu kB\n",
346 PRINT_DEBUG(" partitions to be sized automatically: %d\n",
349 if (mem_needed
> pages
* 4) {
350 PRINT_ERR("Not enough expanded memory available\n");
356 * xpram_sizes[i] != 0; partition i has size xpram_sizes[i] kB
357 * else: ; all partitions with zero xpram_sizes[i]
358 * partition equally the remaining space
361 mem_auto
= ((pages
- mem_needed
/ 4) / mem_auto_no
) * 4;
362 PRINT_INFO(" automatically determined "
363 "partition size: %lu kB\n", mem_auto
);
364 for (i
= 0; i
< xpram_devs
; i
++)
365 if (xpram_sizes
[i
] == 0)
366 xpram_sizes
[i
] = mem_auto
;
371 static struct request_queue
*xpram_queue
;
373 static int __init
xpram_setup_blkdev(void)
375 unsigned long offset
;
378 for (i
= 0; i
< xpram_devs
; i
++) {
379 struct gendisk
*disk
= alloc_disk(1);
382 xpram_disks
[i
] = disk
;
386 * Register xpram major.
388 rc
= register_blkdev(XPRAM_MAJOR
, XPRAM_NAME
);
393 * Assign the other needed values: make request function, sizes and
394 * hardsect size. All the minor devices feature the same value.
396 xpram_queue
= blk_alloc_queue(GFP_KERNEL
);
401 blk_queue_make_request(xpram_queue
, xpram_make_request
);
402 blk_queue_hardsect_size(xpram_queue
, 4096);
405 * Setup device structures.
408 for (i
= 0; i
< xpram_devs
; i
++) {
409 struct gendisk
*disk
= xpram_disks
[i
];
411 xpram_devices
[i
].size
= xpram_sizes
[i
] / 4;
412 xpram_devices
[i
].offset
= offset
;
413 offset
+= xpram_devices
[i
].size
;
414 disk
->major
= XPRAM_MAJOR
;
415 disk
->first_minor
= i
;
416 disk
->fops
= &xpram_devops
;
417 disk
->private_data
= &xpram_devices
[i
];
418 disk
->queue
= xpram_queue
;
419 sprintf(disk
->disk_name
, "slram%d", i
);
420 set_capacity(disk
, xpram_sizes
[i
] << 1);
426 unregister_blkdev(XPRAM_MAJOR
, XPRAM_NAME
);
429 put_disk(xpram_disks
[i
]);
434 * Finally, the init/exit functions.
436 static void __exit
xpram_exit(void)
439 for (i
= 0; i
< xpram_devs
; i
++) {
440 del_gendisk(xpram_disks
[i
]);
441 put_disk(xpram_disks
[i
]);
443 unregister_blkdev(XPRAM_MAJOR
, XPRAM_NAME
);
444 blk_cleanup_queue(xpram_queue
);
447 static int __init
xpram_init(void)
451 /* Find out size of expanded memory. */
452 if (xpram_present() != 0) {
453 PRINT_WARN("No expanded memory available\n");
456 xpram_pages
= xpram_highest_page_index();
457 PRINT_INFO(" %u pages expanded memory found (%lu KB).\n",
458 xpram_pages
, (unsigned long) xpram_pages
*4);
459 rc
= xpram_setup_sizes(xpram_pages
);
462 return xpram_setup_blkdev();
465 module_init(xpram_init
);
466 module_exit(xpram_exit
);