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)
51 static struct sysdev_class xpram_sysclass = {
52 set_kset_name("xpram"),
55 static struct sys_device xpram_sys_device = {
57 .cls = &xpram_sysclass,
61 unsigned int size; /* size of xpram segment in pages */
62 unsigned int offset; /* start page of xpram segment */
65 static xpram_device_t xpram_devices[XPRAM_MAX_DEVS];
66 static unsigned int xpram_sizes[XPRAM_MAX_DEVS];
67 static struct gendisk *xpram_disks[XPRAM_MAX_DEVS];
68 static unsigned int xpram_pages;
69 static int xpram_devs;
72 * Parameter parsing functions.
74 static int __initdata devs = XPRAM_DEVS;
75 static char __initdata *sizes[XPRAM_MAX_DEVS];
77 module_param(devs, int, 0);
78 module_param_array(sizes, charp, NULL, 0);
80 MODULE_PARM_DESC(devs, "number of devices (\"partitions\"), " \
81 "the default is " __MODULE_STRING(XPRAM_DEVS) "\n");
82 MODULE_PARM_DESC(sizes, "list of device (partition) sizes " \
83 "the defaults are 0s \n" \
84 "All devices with size 0 equally partition the "
85 "remaining space on the expanded strorage not "
86 "claimed by explicit sizes\n");
87 MODULE_LICENSE("GPL");
90 * Copy expanded memory page (4kB) into main memory
92 * page_addr: address of target page
93 * xpage_index: index of expandeded memory page
95 * 0: if operation succeeds
96 * -EIO: if pgin failed
97 * -ENXIO: if xpram has vanished
99 static int xpram_page_in (unsigned long page_addr, unsigned int xpage_index)
103 __asm__ __volatile__ (
104 " lhi %0,2\n" /* return unused cc 2 if pgin traps */
105 " .insn rre,0xb22e0000,%1,%2\n" /* pgin %1,%2 */
110 ".section __ex_table,\"a\"\n"
115 ".section __ex_table,\"a\"\n"
121 : "a" (__pa(page_addr)), "a" (xpage_index)
126 PRINT_ERR("expanded storage lost!\n");
130 PRINT_ERR("page in failed for page index %u.\n",
138 * Copy a 4kB page of main memory to an expanded memory page
140 * page_addr: address of source page
141 * xpage_index: index of expandeded memory page
143 * 0: if operation succeeds
144 * -EIO: if pgout failed
145 * -ENXIO: if xpram has vanished
147 static long xpram_page_out (unsigned long page_addr, unsigned int xpage_index)
151 __asm__ __volatile__ (
152 " lhi %0,2\n" /* return unused cc 2 if pgout traps */
153 " .insn rre,0xb22f0000,%1,%2\n" /* pgout %1,%2 */
158 ".section __ex_table,\"a\"\n"
163 ".section __ex_table,\"a\"\n"
169 : "a" (__pa(page_addr)), "a" (xpage_index)
174 PRINT_ERR("expanded storage lost!\n");
178 PRINT_ERR("page out failed for page index %u.\n",
186 * Check if xpram is available.
188 static int __init xpram_present(void)
190 unsigned long mem_page;
193 mem_page = (unsigned long) __get_free_page(GFP_KERNEL);
196 rc = xpram_page_in(mem_page, 0);
198 return rc ? -ENXIO : 0;
202 * Return index of the last available xpram page.
204 static unsigned long __init xpram_highest_page_index(void)
206 unsigned int page_index, add_bit;
207 unsigned long mem_page;
209 mem_page = (unsigned long) __get_free_page(GFP_KERNEL);
214 add_bit = 1ULL << (sizeof(unsigned int)*8 - 1);
215 while (add_bit > 0) {
216 if (xpram_page_in(mem_page, page_index | add_bit) == 0)
217 page_index |= add_bit;
221 free_page (mem_page);
227 * Block device make request function.
229 static int xpram_make_request(request_queue_t *q, struct bio *bio)
231 xpram_device_t *xdev = bio->bi_bdev->bd_disk->private_data;
232 struct bio_vec *bvec;
234 unsigned long page_addr;
238 if ((bio->bi_sector & 7) != 0 || (bio->bi_size & 4095) != 0)
239 /* Request is not page-aligned. */
241 if ((bio->bi_size >> 12) > xdev->size)
242 /* Request size is no page-aligned. */
244 if ((bio->bi_sector >> 3) > 0xffffffffU - xdev->offset)
246 index = (bio->bi_sector >> 3) + xdev->offset;
247 bio_for_each_segment(bvec, bio, i) {
248 page_addr = (unsigned long)
249 kmap(bvec->bv_page) + bvec->bv_offset;
250 bytes = bvec->bv_len;
251 if ((page_addr & 4095) != 0 || (bytes & 4095) != 0)
255 if (bio_data_dir(bio) == READ) {
256 if (xpram_page_in(page_addr, index) != 0)
259 if (xpram_page_out(page_addr, index) != 0)
267 set_bit(BIO_UPTODATE, &bio->bi_flags);
268 bytes = bio->bi_size;
270 bio->bi_end_io(bio, bytes, 0);
273 bio_io_error(bio, bio->bi_size);
277 static int xpram_getgeo(struct block_device *bdev, struct hd_geometry *geo)
282 * get geometry: we have to fake one... trim the size to a
283 * multiple of 64 (32k): tell we have 16 sectors, 4 heads,
284 * whatever cylinders. Tell also that data starts at sector. 4.
286 size = (xpram_pages * 8) & ~0x3f;
287 geo->cylinders = size >> 6;
294 static struct block_device_operations xpram_devops =
296 .owner = THIS_MODULE,
297 .getgeo = xpram_getgeo,
301 * Setup xpram_sizes array.
303 static int __init xpram_setup_sizes(unsigned long pages)
305 unsigned long mem_needed;
306 unsigned long mem_auto;
310 /* Check number of devices. */
311 if (devs <= 0 || devs > XPRAM_MAX_DEVS) {
312 PRINT_ERR("invalid number %d of devices\n",devs);
318 * Copy sizes array to xpram_sizes and align partition
319 * sizes to page boundary.
323 for (i = 0; i < xpram_devs; i++) {
326 (memparse(sizes[i], &sizes[i]) + 3) & -4UL;
328 mem_needed += xpram_sizes[i];
333 PRINT_INFO(" number of devices (partitions): %d \n", xpram_devs);
334 for (i = 0; i < xpram_devs; i++) {
336 PRINT_INFO(" size of partition %d: %u kB\n",
339 PRINT_INFO(" size of partition %d to be set "
340 "automatically\n",i);
342 PRINT_DEBUG(" memory needed (for sized partitions): %lu kB\n",
344 PRINT_DEBUG(" partitions to be sized automatically: %d\n",
347 if (mem_needed > pages * 4) {
348 PRINT_ERR("Not enough expanded memory available\n");
354 * xpram_sizes[i] != 0; partition i has size xpram_sizes[i] kB
355 * else: ; all partitions with zero xpram_sizes[i]
356 * partition equally the remaining space
359 mem_auto = ((pages - mem_needed / 4) / mem_auto_no) * 4;
360 PRINT_INFO(" automatically determined "
361 "partition size: %lu kB\n", mem_auto);
362 for (i = 0; i < xpram_devs; i++)
363 if (xpram_sizes[i] == 0)
364 xpram_sizes[i] = mem_auto;
369 static struct request_queue *xpram_queue;
371 static int __init xpram_setup_blkdev(void)
373 unsigned long offset;
376 for (i = 0; i < xpram_devs; i++) {
377 struct gendisk *disk = alloc_disk(1);
380 xpram_disks[i] = disk;
384 * Register xpram major.
386 rc = register_blkdev(XPRAM_MAJOR, XPRAM_NAME);
391 * Assign the other needed values: make request function, sizes and
392 * hardsect size. All the minor devices feature the same value.
394 xpram_queue = blk_alloc_queue(GFP_KERNEL);
399 blk_queue_make_request(xpram_queue, xpram_make_request);
400 blk_queue_hardsect_size(xpram_queue, 4096);
403 * Setup device structures.
406 for (i = 0; i < xpram_devs; i++) {
407 struct gendisk *disk = xpram_disks[i];
409 xpram_devices[i].size = xpram_sizes[i] / 4;
410 xpram_devices[i].offset = offset;
411 offset += xpram_devices[i].size;
412 disk->major = XPRAM_MAJOR;
413 disk->first_minor = i;
414 disk->fops = &xpram_devops;
415 disk->private_data = &xpram_devices[i];
416 disk->queue = xpram_queue;
417 sprintf(disk->disk_name, "slram%d", i);
418 set_capacity(disk, xpram_sizes[i] << 1);
424 unregister_blkdev(XPRAM_MAJOR, XPRAM_NAME);
427 put_disk(xpram_disks[i]);
432 * Finally, the init/exit functions.
434 static void __exit xpram_exit(void)
437 for (i = 0; i < xpram_devs; i++) {
438 del_gendisk(xpram_disks[i]);
439 put_disk(xpram_disks[i]);
441 unregister_blkdev(XPRAM_MAJOR, XPRAM_NAME);
442 blk_cleanup_queue(xpram_queue);
443 sysdev_unregister(&xpram_sys_device);
444 sysdev_class_unregister(&xpram_sysclass);
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 rc = sysdev_class_register(&xpram_sysclass);
466 rc = sysdev_register(&xpram_sys_device);
468 sysdev_class_unregister(&xpram_sysclass);
471 rc = xpram_setup_blkdev();
473 sysdev_unregister(&xpram_sys_device);
477 module_init(xpram_init);
478 module_exit(xpram_exit);