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/device.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 50typedef 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 55static xpram_device_t xpram_devices[XPRAM_MAX_DEVS]; 56static unsigned int xpram_sizes[XPRAM_MAX_DEVS]; 57static struct gendisk *xpram_disks[XPRAM_MAX_DEVS]; 58static struct request_queue *xpram_queues[XPRAM_MAX_DEVS]; 59static unsigned int xpram_pages; 60static int xpram_devs; 61 62/* 63 * Parameter parsing functions. 64 */ 65static int devs = XPRAM_DEVS; 66static char *sizes[XPRAM_MAX_DEVS]; 67 68module_param(devs, int, 0); 69module_param_array(sizes, charp, NULL, 0); 70 71MODULE_PARM_DESC(devs, "number of devices (\"partitions\"), " \ 72 "the default is " __MODULE_STRING(XPRAM_DEVS) "\n"); 73MODULE_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"); 78MODULE_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 */ 90static 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 */ 120static 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 */ 143static 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 */ 159static 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 */ 184static void 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 struct bvec_iter iter; 189 unsigned int index; 190 unsigned long page_addr; 191 unsigned long bytes; 192 193 if ((bio->bi_iter.bi_sector & 7) != 0 || 194 (bio->bi_iter.bi_size & 4095) != 0) 195 /* Request is not page-aligned. */ 196 goto fail; 197 if ((bio->bi_iter.bi_size >> 12) > xdev->size) 198 /* Request size is no page-aligned. */ 199 goto fail; 200 if ((bio->bi_iter.bi_sector >> 3) > 0xffffffffU - xdev->offset) 201 goto fail; 202 index = (bio->bi_iter.bi_sector >> 3) + xdev->offset; 203 bio_for_each_segment(bvec, bio, iter) { 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; 226fail: 227 bio_io_error(bio); 228} 229 230static 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 247static 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 */ 256static 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 char *sizes_end; 262 int mem_auto_no; 263 int i; 264 265 /* Check number of devices. */ 266 if (devs <= 0 || devs > XPRAM_MAX_DEVS) { 267 pr_err("%d is not a valid number of XPRAM 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_end, 0); 281 switch (*sizes_end) { 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 pr_info(" number of devices (partitions): %d \n", xpram_devs); 299 for (i = 0; i < xpram_devs; i++) { 300 if (xpram_sizes[i]) 301 pr_info(" size of partition %d: %u kB\n", 302 i, xpram_sizes[i]); 303 else 304 pr_info(" size of partition %d to be set " 305 "automatically\n",i); 306 } 307 pr_info(" memory needed (for sized partitions): %lu kB\n", 308 mem_needed); 309 pr_info(" partitions to be sized automatically: %d\n", 310 mem_auto_no); 311 312 if (mem_needed > pages * 4) { 313 pr_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 pr_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 334static 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 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, xpram_queues[i]); 349 queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, xpram_queues[i]); 350 blk_queue_make_request(xpram_queues[i], xpram_make_request); 351 blk_queue_logical_block_size(xpram_queues[i], 4096); 352 } 353 354 /* 355 * Register xpram major. 356 */ 357 rc = register_blkdev(XPRAM_MAJOR, XPRAM_NAME); 358 if (rc < 0) 359 goto out; 360 361 /* 362 * Setup device structures. 363 */ 364 offset = 0; 365 for (i = 0; i < xpram_devs; i++) { 366 struct gendisk *disk = xpram_disks[i]; 367 368 xpram_devices[i].size = xpram_sizes[i] / 4; 369 xpram_devices[i].offset = offset; 370 offset += xpram_devices[i].size; 371 disk->major = XPRAM_MAJOR; 372 disk->first_minor = i; 373 disk->fops = &xpram_devops; 374 disk->private_data = &xpram_devices[i]; 375 disk->queue = xpram_queues[i]; 376 sprintf(disk->disk_name, "slram%d", i); 377 set_capacity(disk, xpram_sizes[i] << 1); 378 add_disk(disk); 379 } 380 381 return 0; 382out: 383 while (i--) { 384 blk_cleanup_queue(xpram_queues[i]); 385 put_disk(xpram_disks[i]); 386 } 387 return rc; 388} 389 390/* 391 * Resume failed: Print error message and call panic. 392 */ 393static void xpram_resume_error(const char *message) 394{ 395 pr_err("Resuming the system failed: %s\n", message); 396 panic("xpram resume error\n"); 397} 398 399/* 400 * Check if xpram setup changed between suspend and resume. 401 */ 402static int xpram_restore(struct device *dev) 403{ 404 if (!xpram_pages) 405 return 0; 406 if (xpram_present() != 0) 407 xpram_resume_error("xpram disappeared"); 408 if (xpram_pages != xpram_highest_page_index() + 1) 409 xpram_resume_error("Size of xpram changed"); 410 return 0; 411} 412 413static const struct dev_pm_ops xpram_pm_ops = { 414 .restore = xpram_restore, 415}; 416 417static struct platform_driver xpram_pdrv = { 418 .driver = { 419 .name = XPRAM_NAME, 420 .owner = THIS_MODULE, 421 .pm = &xpram_pm_ops, 422 }, 423}; 424 425static struct platform_device *xpram_pdev; 426 427/* 428 * Finally, the init/exit functions. 429 */ 430static void __exit xpram_exit(void) 431{ 432 int i; 433 for (i = 0; i < xpram_devs; i++) { 434 del_gendisk(xpram_disks[i]); 435 blk_cleanup_queue(xpram_queues[i]); 436 put_disk(xpram_disks[i]); 437 } 438 unregister_blkdev(XPRAM_MAJOR, XPRAM_NAME); 439 platform_device_unregister(xpram_pdev); 440 platform_driver_unregister(&xpram_pdrv); 441} 442 443static int __init xpram_init(void) 444{ 445 int rc; 446 447 /* Find out size of expanded memory. */ 448 if (xpram_present() != 0) { 449 pr_err("No expanded memory available\n"); 450 return -ENODEV; 451 } 452 xpram_pages = xpram_highest_page_index() + 1; 453 pr_info(" %u pages expanded memory found (%lu KB).\n", 454 xpram_pages, (unsigned long) xpram_pages*4); 455 rc = xpram_setup_sizes(xpram_pages); 456 if (rc) 457 return rc; 458 rc = platform_driver_register(&xpram_pdrv); 459 if (rc) 460 return rc; 461 xpram_pdev = platform_device_register_simple(XPRAM_NAME, -1, NULL, 0); 462 if (IS_ERR(xpram_pdev)) { 463 rc = PTR_ERR(xpram_pdev); 464 goto fail_platform_driver_unregister; 465 } 466 rc = xpram_setup_blkdev(); 467 if (rc) 468 goto fail_platform_device_unregister; 469 return 0; 470 471fail_platform_device_unregister: 472 platform_device_unregister(xpram_pdev); 473fail_platform_driver_unregister: 474 platform_driver_unregister(&xpram_pdrv); 475 return rc; 476} 477 478module_init(xpram_init); 479module_exit(xpram_exit); 480