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 <linux/devfs_fs_kernel.h>
40 #include <asm/uaccess.h>
42 #define XPRAM_NAME "xpram"
43 #define XPRAM_DEVS 1 /* one partition */
44 #define XPRAM_MAX_DEVS 32 /* maximal number of devices (partitions) */
46 #define PRINT_DEBUG(x...) printk(KERN_DEBUG XPRAM_NAME " debug:" x)
47 #define PRINT_INFO(x...) printk(KERN_INFO XPRAM_NAME " info:" x)
48 #define PRINT_WARN(x...) printk(KERN_WARNING XPRAM_NAME " warning:" x)
49 #define PRINT_ERR(x...) printk(KERN_ERR XPRAM_NAME " error:" x)
52 static struct sysdev_class xpram_sysclass = {
53 set_kset_name("xpram"),
56 static struct sys_device xpram_sys_device = {
58 .cls = &xpram_sysclass,
62 unsigned int size; /* size of xpram segment in pages */
63 unsigned int offset; /* start page of xpram segment */
66 static xpram_device_t xpram_devices[XPRAM_MAX_DEVS];
67 static unsigned int xpram_sizes[XPRAM_MAX_DEVS];
68 static struct gendisk *xpram_disks[XPRAM_MAX_DEVS];
69 static unsigned int xpram_pages;
70 static int xpram_devs;
73 * Parameter parsing functions.
75 static int devs = XPRAM_DEVS;
76 static unsigned int sizes[XPRAM_MAX_DEVS];
77 static unsigned int sizes_count;
79 module_param(devs, int, 0);
80 module_param_array(sizes, int, sizes_count, 0);
82 MODULE_PARM_DESC(devs, "number of devices (\"partitions\"), " \
83 "the default is " __MODULE_STRING(XPRAM_DEVS) "\n");
84 MODULE_PARM_DESC(sizes, "list of device (partition) sizes " \
85 "the defaults are 0s \n" \
86 "All devices with size 0 equally partition the "
87 "remaining space on the expanded strorage not "
88 "claimed by explicit sizes\n");
89 MODULE_LICENSE("GPL");
93 * Parses the kernel parameters given in the kernel parameter line.
94 * The expected format is
95 * <number_of_partitions>[","<partition_size>]*
97 * devices is a positive integer that initializes xpram_devs
98 * each size is a non-negative integer possibly followed by a
99 * magnitude (k,K,m,M,g,G), the list of sizes initialises
103 * str: substring of kernel parameter line that contains xprams
106 * Result 0 on success, -EINVAL else -- only for Version > 2.3
109 * the global variabls devs is set to the value of
110 * <number_of_partitions> and sizes[i] is set to the i-th
111 * partition size (if provided). A parsing error of a value
112 * results in this value being set to -EINVAL.
114 static int __init xpram_setup (char *str)
119 devs = simple_strtoul(str, &cp, 10);
120 if (cp <= str || devs > XPRAM_MAX_DEVS)
122 for (i = 0; (i < devs) && (*cp++ == ','); i++) {
123 sizes[i] = simple_strtoul(cp, &cp, 10);
124 if (*cp == 'g' || *cp == 'G') {
127 } else if (*cp == 'm' || *cp == 'M') {
130 } else if (*cp == 'k' || *cp == 'K')
132 while (isspace(*cp)) cp++;
134 if (*cp == ',' && i >= devs)
135 PRINT_WARN("partition sizes list has too many entries.\n");
137 PRINT_WARN("ignored '%s' at end of parameter string.\n", cp);
141 __setup("xpram_parts=", xpram_setup);
145 * Copy expanded memory page (4kB) into main memory
147 * page_addr: address of target page
148 * xpage_index: index of expandeded memory page
150 * 0: if operation succeeds
151 * -EIO: if pgin failed
152 * -ENXIO: if xpram has vanished
154 static int xpram_page_in (unsigned long page_addr, unsigned int xpage_index)
158 __asm__ __volatile__ (
159 " lhi %0,2\n" /* return unused cc 2 if pgin traps */
160 " .insn rre,0xb22e0000,%1,%2\n" /* pgin %1,%2 */
164 #ifndef CONFIG_ARCH_S390X
165 ".section __ex_table,\"a\"\n"
170 ".section __ex_table,\"a\"\n"
176 : "a" (__pa(page_addr)), "a" (xpage_index)
181 PRINT_ERR("expanded storage lost!\n");
185 PRINT_ERR("page in failed for page index %u.\n",
193 * Copy a 4kB page of main memory to an expanded memory page
195 * page_addr: address of source page
196 * xpage_index: index of expandeded memory page
198 * 0: if operation succeeds
199 * -EIO: if pgout failed
200 * -ENXIO: if xpram has vanished
202 static long xpram_page_out (unsigned long page_addr, unsigned int xpage_index)
206 __asm__ __volatile__ (
207 " lhi %0,2\n" /* return unused cc 2 if pgout traps */
208 " .insn rre,0xb22f0000,%1,%2\n" /* pgout %1,%2 */
212 #ifndef CONFIG_ARCH_S390X
213 ".section __ex_table,\"a\"\n"
218 ".section __ex_table,\"a\"\n"
224 : "a" (__pa(page_addr)), "a" (xpage_index)
229 PRINT_ERR("expanded storage lost!\n");
233 PRINT_ERR("page out failed for page index %u.\n",
241 * Check if xpram is available.
243 static int __init xpram_present(void)
245 unsigned long mem_page;
248 mem_page = (unsigned long) __get_free_page(GFP_KERNEL);
251 rc = xpram_page_in(mem_page, 0);
253 return rc ? -ENXIO : 0;
257 * Return index of the last available xpram page.
259 static unsigned long __init xpram_highest_page_index(void)
261 unsigned int page_index, add_bit;
262 unsigned long mem_page;
264 mem_page = (unsigned long) __get_free_page(GFP_KERNEL);
269 add_bit = 1ULL << (sizeof(unsigned int)*8 - 1);
270 while (add_bit > 0) {
271 if (xpram_page_in(mem_page, page_index | add_bit) == 0)
272 page_index |= add_bit;
276 free_page (mem_page);
282 * Block device make request function.
284 static int xpram_make_request(request_queue_t *q, struct bio *bio)
286 xpram_device_t *xdev = bio->bi_bdev->bd_disk->private_data;
287 struct bio_vec *bvec;
289 unsigned long page_addr;
293 if ((bio->bi_sector & 7) != 0 || (bio->bi_size & 4095) != 0)
294 /* Request is not page-aligned. */
296 if ((bio->bi_size >> 12) > xdev->size)
297 /* Request size is no page-aligned. */
299 if ((bio->bi_sector >> 3) > 0xffffffffU - xdev->offset)
301 index = (bio->bi_sector >> 3) + xdev->offset;
302 bio_for_each_segment(bvec, bio, i) {
303 page_addr = (unsigned long)
304 kmap(bvec->bv_page) + bvec->bv_offset;
305 bytes = bvec->bv_len;
306 if ((page_addr & 4095) != 0 || (bytes & 4095) != 0)
310 if (bio_data_dir(bio) == READ) {
311 if (xpram_page_in(page_addr, index) != 0)
314 if (xpram_page_out(page_addr, index) != 0)
322 set_bit(BIO_UPTODATE, &bio->bi_flags);
323 bytes = bio->bi_size;
325 bio->bi_end_io(bio, bytes, 0);
328 bio_io_error(bio, bio->bi_size);
332 static int xpram_ioctl (struct inode *inode, struct file *filp,
333 unsigned int cmd, unsigned long arg)
335 struct hd_geometry __user *geo;
337 if (cmd != HDIO_GETGEO)
340 * get geometry: we have to fake one... trim the size to a
341 * multiple of 64 (32k): tell we have 16 sectors, 4 heads,
342 * whatever cylinders. Tell also that data starts at sector. 4.
344 geo = (struct hd_geometry __user *) arg;
345 size = (xpram_pages * 8) & ~0x3f;
346 put_user(size >> 6, &geo->cylinders);
347 put_user(4, &geo->heads);
348 put_user(16, &geo->sectors);
349 put_user(4, &geo->start);
353 static struct block_device_operations xpram_devops =
355 .owner = THIS_MODULE,
356 .ioctl = xpram_ioctl,
360 * Setup xpram_sizes array.
362 static int __init xpram_setup_sizes(unsigned long pages)
364 unsigned long mem_needed;
365 unsigned long mem_auto;
369 /* Check number of devices. */
370 if (devs <= 0 || devs > XPRAM_MAX_DEVS) {
371 PRINT_ERR("invalid number %d of devices\n",devs);
377 * Copy sizes array to xpram_sizes and align partition
378 * sizes to page boundary.
382 for (i = 0; i < xpram_devs; i++) {
383 xpram_sizes[i] = (sizes[i] + 3) & -4UL;
385 mem_needed += xpram_sizes[i];
390 PRINT_INFO(" number of devices (partitions): %d \n", xpram_devs);
391 for (i = 0; i < xpram_devs; i++) {
393 PRINT_INFO(" size of partition %d: %u kB\n",
396 PRINT_INFO(" size of partition %d to be set "
397 "automatically\n",i);
399 PRINT_DEBUG(" memory needed (for sized partitions): %lu kB\n",
401 PRINT_DEBUG(" partitions to be sized automatically: %d\n",
404 if (mem_needed > pages * 4) {
405 PRINT_ERR("Not enough expanded memory available\n");
411 * xpram_sizes[i] != 0; partition i has size xpram_sizes[i] kB
412 * else: ; all partitions with zero xpram_sizes[i]
413 * partition equally the remaining space
416 mem_auto = ((pages - mem_needed / 4) / mem_auto_no) * 4;
417 PRINT_INFO(" automatically determined "
418 "partition size: %lu kB\n", mem_auto);
419 for (i = 0; i < xpram_devs; i++)
420 if (xpram_sizes[i] == 0)
421 xpram_sizes[i] = mem_auto;
426 static struct request_queue *xpram_queue;
428 static int __init xpram_setup_blkdev(void)
430 unsigned long offset;
433 for (i = 0; i < xpram_devs; i++) {
434 struct gendisk *disk = alloc_disk(1);
437 xpram_disks[i] = disk;
441 * Register xpram major.
443 rc = register_blkdev(XPRAM_MAJOR, XPRAM_NAME);
447 devfs_mk_dir("slram");
450 * Assign the other needed values: make request function, sizes and
451 * hardsect size. All the minor devices feature the same value.
453 xpram_queue = blk_alloc_queue(GFP_KERNEL);
458 blk_queue_make_request(xpram_queue, xpram_make_request);
459 blk_queue_hardsect_size(xpram_queue, 4096);
462 * Setup device structures.
465 for (i = 0; i < xpram_devs; i++) {
466 struct gendisk *disk = xpram_disks[i];
468 xpram_devices[i].size = xpram_sizes[i] / 4;
469 xpram_devices[i].offset = offset;
470 offset += xpram_devices[i].size;
471 disk->major = XPRAM_MAJOR;
472 disk->first_minor = i;
473 disk->fops = &xpram_devops;
474 disk->private_data = &xpram_devices[i];
475 disk->queue = xpram_queue;
476 sprintf(disk->disk_name, "slram%d", i);
477 sprintf(disk->devfs_name, "slram/%d", i);
478 set_capacity(disk, xpram_sizes[i] << 1);
484 devfs_remove("slram");
485 unregister_blkdev(XPRAM_MAJOR, XPRAM_NAME);
488 put_disk(xpram_disks[i]);
493 * Finally, the init/exit functions.
495 static void __exit xpram_exit(void)
498 for (i = 0; i < xpram_devs; i++) {
499 del_gendisk(xpram_disks[i]);
500 put_disk(xpram_disks[i]);
502 unregister_blkdev(XPRAM_MAJOR, XPRAM_NAME);
503 devfs_remove("slram");
504 blk_cleanup_queue(xpram_queue);
505 sysdev_unregister(&xpram_sys_device);
506 sysdev_class_unregister(&xpram_sysclass);
509 static int __init xpram_init(void)
513 /* Find out size of expanded memory. */
514 if (xpram_present() != 0) {
515 PRINT_WARN("No expanded memory available\n");
518 xpram_pages = xpram_highest_page_index();
519 PRINT_INFO(" %u pages expanded memory found (%lu KB).\n",
520 xpram_pages, (unsigned long) xpram_pages*4);
521 rc = xpram_setup_sizes(xpram_pages);
524 rc = sysdev_class_register(&xpram_sysclass);
528 rc = sysdev_register(&xpram_sys_device);
530 sysdev_class_unregister(&xpram_sysclass);
533 rc = xpram_setup_blkdev();
535 sysdev_unregister(&xpram_sys_device);
539 module_init(xpram_init);
540 module_exit(xpram_exit);