git.oblomov.eu Git - linux-2.6/blob - drivers/idle/i7300_idle.c

   1 /*
   2  * (C) Copyright 2008 Intel Corporation
   3  * Authors:
   4  * Andy Henroid <andrew.d.henroid@intel.com>
   5  * Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
   6  */
   7
   8 /*
   9  * Save DIMM power on Intel 7300-based platforms when all CPUs/cores
  10  * are idle, using the DIMM thermal throttling capability.
  11  *
  12  * This driver depends on the Intel integrated DMA controller (I/O AT).
  13  * If the driver for I/O AT (drivers/dma/ioatdma*) is also enabled,
  14  * this driver should work cooperatively.
  15  */
  16
  17 /* #define DEBUG */
  18
  19 #include <linux/module.h>
  20 #include <linux/pci.h>
  21 #include <linux/sched.h>
  22 #include <linux/notifier.h>
  23 #include <linux/cpumask.h>
  24 #include <linux/ktime.h>
  25 #include <linux/delay.h>
  26 #include <linux/debugfs.h>
  27 #include <linux/stop_machine.h>
  28
  29 #include <asm/idle.h>
  30
  31 #include "../dma/ioatdma_hw.h"
  32 #include "../dma/ioatdma_registers.h"
  33
  34 #define I7300_IDLE_DRIVER_VERSION       "1.55"
  35 #define I7300_PRINT                     "i7300_idle:"
  36
  37 static int debug;
  38 module_param_named(debug, debug, uint, 0644);
  39 MODULE_PARM_DESC(debug, "Enable debug printks in this driver");
  40
  41 #define dprintk(fmt, arg...) \
  42         do { if (debug) printk(KERN_INFO I7300_PRINT fmt, ##arg); } while (0)
  43
  44 /*
  45  * Value to set THRTLOW to when initiating throttling
  46  *  0 = No throttling
  47  *  1 = Throttle when > 4 activations per eval window (Maximum throttling)
  48  *  2 = Throttle when > 8 activations
  49  *  168 = Throttle when > 168 activations (Minimum throttling)
  50  */
  51 #define MAX_THRTLWLIMIT         168
  52 static uint i7300_idle_thrtlowlm = 1;
  53 module_param_named(thrtlwlimit, i7300_idle_thrtlowlm, uint, 0644);
  54 MODULE_PARM_DESC(thrtlwlimit,
  55                 "Value for THRTLOWLM activation field "
  56                 "(0 = disable throttle, 1 = Max throttle, 168 = Min throttle)");
  57
  58 /*
  59  * simple invocation and duration statistics
  60  */
  61 static unsigned long total_starts;
  62 static unsigned long total_us;
  63
  64 #ifdef DEBUG
  65 static unsigned long past_skip;
  66 #endif
  67
  68 static struct pci_dev *fbd_dev;
  69
  70 static spinlock_t i7300_idle_lock;
  71 static int i7300_idle_active;
  72
  73 static u8 i7300_idle_thrtctl_saved;
  74 static u8 i7300_idle_thrtlow_saved;
  75 static u32 i7300_idle_mc_saved;
  76
  77 static cpumask_t idle_cpumask;
  78 static ktime_t start_ktime;
  79 static unsigned long avg_idle_us;
  80
  81 static struct dentry *debugfs_dir;
  82
  83 /* Begin: I/O AT Helper routines */
  84
  85 #define IOAT_CHANBASE(ioat_ctl, chan) (ioat_ctl + 0x80 + 0x80 * chan)
  86 /* Snoop control (disable snoops when coherency is not important) */
  87 #define IOAT_DESC_SADDR_SNP_CTL (1UL << 1)
  88 #define IOAT_DESC_DADDR_SNP_CTL (1UL << 2)
  89
  90 static struct pci_dev *ioat_dev;
  91 static struct ioat_dma_descriptor *ioat_desc; /* I/O AT desc & data (1 page) */
  92 static unsigned long ioat_desc_phys;
  93 static u8 *ioat_iomap; /* I/O AT memory-mapped control regs (aka CB_BAR) */
  94 static u8 *ioat_chanbase;
  95
  96 /* Start I/O AT memory copy */
  97 static int i7300_idle_ioat_start(void)
  98 {
  99         u32 err;
 100         /* Clear error (due to circular descriptor pointer) */
 101         err = readl(ioat_chanbase + IOAT_CHANERR_OFFSET);
 102         if (err)
 103                 writel(err, ioat_chanbase + IOAT_CHANERR_OFFSET);
 104
 105         writeb(IOAT_CHANCMD_START, ioat_chanbase + IOAT1_CHANCMD_OFFSET);
 106         return 0;
 107 }
 108
 109 /* Stop I/O AT memory copy */
 110 static void i7300_idle_ioat_stop(void)
 111 {
 112         int i;
 113         u8 sts;
 114
 115         for (i = 0; i < 5; i++) {
 116                 writeb(IOAT_CHANCMD_RESET,
 117                         ioat_chanbase + IOAT1_CHANCMD_OFFSET);
 118
 119                 udelay(10);
 120
 121                 sts = readq(ioat_chanbase + IOAT1_CHANSTS_OFFSET) &
 122                         IOAT_CHANSTS_DMA_TRANSFER_STATUS;
 123
 124                 if (sts != IOAT_CHANSTS_DMA_TRANSFER_STATUS_ACTIVE)
 125                         break;
 126
 127         }
 128
 129         if (i == 5)
 130                 dprintk("failed to suspend+reset I/O AT after 5 retries\n");
 131
 132 }
 133
 134 /* Test I/O AT by copying 1024 byte from 2k to 1k */
 135 static int __init i7300_idle_ioat_selftest(u8 *ctl,
 136                 struct ioat_dma_descriptor *desc, unsigned long desc_phys)
 137 {
 138         u64 chan_sts;
 139
 140         memset(desc, 0, 2048);
 141         memset((u8 *) desc + 2048, 0xab, 1024);
 142
 143         desc[0].size = 1024;
 144         desc[0].ctl = 0;
 145         desc[0].src_addr = desc_phys + 2048;
 146         desc[0].dst_addr = desc_phys + 1024;
 147         desc[0].next = 0;
 148
 149         writeb(IOAT_CHANCMD_RESET, ioat_chanbase + IOAT1_CHANCMD_OFFSET);
 150         writeb(IOAT_CHANCMD_START, ioat_chanbase + IOAT1_CHANCMD_OFFSET);
 151
 152         udelay(1000);
 153
 154         chan_sts = readq(ioat_chanbase + IOAT1_CHANSTS_OFFSET) &
 155                         IOAT_CHANSTS_DMA_TRANSFER_STATUS;
 156
 157         if (chan_sts != IOAT_CHANSTS_DMA_TRANSFER_STATUS_DONE) {
 158                 /* Not complete, reset the channel */
 159                 writeb(IOAT_CHANCMD_RESET,
 160                        ioat_chanbase + IOAT1_CHANCMD_OFFSET);
 161                 return -1;
 162         }
 163
 164         if (*(u32 *) ((u8 *) desc + 3068) != 0xabababab ||
 165             *(u32 *) ((u8 *) desc + 2044) != 0xabababab) {
 166                 dprintk("Data values src 0x%x, dest 0x%x, memset 0x%x\n",
 167                         *(u32 *) ((u8 *) desc + 2048),
 168                         *(u32 *) ((u8 *) desc + 1024),
 169                         *(u32 *) ((u8 *) desc + 3072));
 170                 return -1;
 171         }
 172         return 0;
 173 }
 174
 175 static struct device dummy_dma_dev = {
 176         .bus_id = "fallback device",
 177         .coherent_dma_mask = DMA_64BIT_MASK,
 178         .dma_mask = &dummy_dma_dev.coherent_dma_mask,
 179 };
 180
 181 /* Setup and initialize I/O AT */
 182 /* This driver needs I/O AT as the throttling takes effect only when there is
 183  * some memory activity. We use I/O AT to set up a dummy copy, while all CPUs
 184  * go idle and memory is throttled.
 185  */
 186 static int __init i7300_idle_ioat_init(void)
 187 {
 188         u8 ver, chan_count, ioat_chan;
 189         u16 chan_ctl;
 190
 191         ioat_iomap = (u8 *) ioremap_nocache(pci_resource_start(ioat_dev, 0),
 192                                             pci_resource_len(ioat_dev, 0));
 193
 194         if (!ioat_iomap) {
 195                 printk(KERN_ERR I7300_PRINT "failed to map I/O AT registers\n");
 196                 goto err_ret;
 197         }
 198
 199         ver = readb(ioat_iomap + IOAT_VER_OFFSET);
 200         if (ver != IOAT_VER_1_2) {
 201                 printk(KERN_ERR I7300_PRINT "unknown I/O AT version (%u.%u)\n",
 202                         ver >> 4, ver & 0xf);
 203                 goto err_unmap;
 204         }
 205
 206         chan_count = readb(ioat_iomap + IOAT_CHANCNT_OFFSET);
 207         if (!chan_count) {
 208                 printk(KERN_ERR I7300_PRINT "unexpected # of I/O AT channels "
 209                         "(%u)\n",
 210                         chan_count);
 211                 goto err_unmap;
 212         }
 213
 214         ioat_chan = chan_count - 1;
 215         ioat_chanbase = IOAT_CHANBASE(ioat_iomap, ioat_chan);
 216
 217         chan_ctl = readw(ioat_chanbase + IOAT_CHANCTRL_OFFSET);
 218         if (chan_ctl & IOAT_CHANCTRL_CHANNEL_IN_USE) {
 219                 printk(KERN_ERR I7300_PRINT "channel %d in use\n", ioat_chan);
 220                 goto err_unmap;
 221         }
 222
 223         writew(IOAT_CHANCTRL_CHANNEL_IN_USE,
 224                 ioat_chanbase + IOAT_CHANCTRL_OFFSET);
 225
 226         ioat_desc = (struct ioat_dma_descriptor *)dma_alloc_coherent(
 227                         &dummy_dma_dev, 4096,
 228                         (dma_addr_t *)&ioat_desc_phys, GFP_KERNEL);
 229         if (!ioat_desc) {
 230                 printk(KERN_ERR I7300_PRINT "failed to allocate I/O AT desc\n");
 231                 goto err_mark_unused;
 232         }
 233
 234         writel(ioat_desc_phys & 0xffffffffUL,
 235                ioat_chanbase + IOAT1_CHAINADDR_OFFSET_LOW);
 236         writel(ioat_desc_phys >> 32,
 237                ioat_chanbase + IOAT1_CHAINADDR_OFFSET_HIGH);
 238
 239         if (i7300_idle_ioat_selftest(ioat_iomap, ioat_desc, ioat_desc_phys)) {
 240                 printk(KERN_ERR I7300_PRINT "I/O AT self-test failed\n");
 241                 goto err_free;
 242         }
 243
 244         /* Setup circular I/O AT descriptor chain */
 245         ioat_desc[0].ctl = IOAT_DESC_SADDR_SNP_CTL | IOAT_DESC_DADDR_SNP_CTL;
 246         ioat_desc[0].src_addr = ioat_desc_phys + 2048;
 247         ioat_desc[0].dst_addr = ioat_desc_phys + 3072;
 248         ioat_desc[0].size = 128;
 249         ioat_desc[0].next = ioat_desc_phys + sizeof(struct ioat_dma_descriptor);
 250
 251         ioat_desc[1].ctl = ioat_desc[0].ctl;
 252         ioat_desc[1].src_addr = ioat_desc[0].src_addr;
 253         ioat_desc[1].dst_addr = ioat_desc[0].dst_addr;
 254         ioat_desc[1].size = ioat_desc[0].size;
 255         ioat_desc[1].next = ioat_desc_phys;
 256
 257         return 0;
 258
 259 err_free:
 260         dma_free_coherent(&dummy_dma_dev, 4096, (void *)ioat_desc, 0);
 261 err_mark_unused:
 262         writew(0, ioat_chanbase + IOAT_CHANCTRL_OFFSET);
 263 err_unmap:
 264         iounmap(ioat_iomap);
 265 err_ret:
 266         return -ENODEV;
 267 }
 268
 269 /* Cleanup I/O AT */
 270 static void __exit i7300_idle_ioat_exit(void)
 271 {
 272         int i;
 273         u64 chan_sts;
 274
 275         i7300_idle_ioat_stop();
 276
 277         /* Wait for a while for the channel to halt before releasing */
 278         for (i = 0; i < 10; i++) {
 279                 writeb(IOAT_CHANCMD_RESET,
 280                        ioat_chanbase + IOAT1_CHANCMD_OFFSET);
 281
 282                 chan_sts = readq(ioat_chanbase + IOAT1_CHANSTS_OFFSET) &
 283                         IOAT_CHANSTS_DMA_TRANSFER_STATUS;
 284
 285                 if (chan_sts != IOAT_CHANSTS_DMA_TRANSFER_STATUS_ACTIVE) {
 286                         writew(0, ioat_chanbase + IOAT_CHANCTRL_OFFSET);
 287                         break;
 288                 }
 289                 udelay(1000);
 290         }
 291
 292         chan_sts = readq(ioat_chanbase + IOAT1_CHANSTS_OFFSET) &
 293                         IOAT_CHANSTS_DMA_TRANSFER_STATUS;
 294
 295         /*
 296          * We tried to reset multiple times. If IO A/T channel is still active
 297          * flag an error and return without cleanup. Memory leak is better
 298          * than random corruption in that extreme error situation.
 299          */
 300         if (chan_sts == IOAT_CHANSTS_DMA_TRANSFER_STATUS_ACTIVE) {
 301                 printk(KERN_ERR I7300_PRINT "Unable to stop IO A/T channels."
 302                         " Not freeing resources\n");
 303                 return;
 304         }
 305
 306         dma_free_coherent(&dummy_dma_dev, 4096, (void *)ioat_desc, 0);
 307         iounmap(ioat_iomap);
 308 }
 309
 310 /* End: I/O AT Helper routines */
 311
 312 #define DIMM_THRTLOW 0x64
 313 #define DIMM_THRTCTL 0x67
 314 #define DIMM_THRTCTL_THRMHUNT (1UL << 0)
 315 #define DIMM_MC 0x40
 316 #define DIMM_GTW_MODE (1UL << 17)
 317 #define DIMM_GBLACT 0x60
 318
 319 /*
 320  * Keep track of an exponential-decaying average of recent idle durations.
 321  * The latest duration gets DURATION_WEIGHT_PCT percentage weight
 322  * in this average, with the old average getting the remaining weight.
 323  *
 324  * High weights emphasize recent history, low weights include long history.
 325  */
 326 #define DURATION_WEIGHT_PCT 55
 327
 328 /*
 329  * When the decaying average of recent durations or the predicted duration
 330  * of the next timer interrupt is shorter than duration_threshold, the
 331  * driver will decline to throttle.
 332  */
 333 #define DURATION_THRESHOLD_US 100
 334
 335
 336 /* Store DIMM thermal throttle configuration */
 337 static int i7300_idle_thrt_save(void)
 338 {
 339         u32 new_mc_val;
 340         u8 gblactlm;
 341
 342         pci_read_config_byte(fbd_dev, DIMM_THRTCTL, &i7300_idle_thrtctl_saved);
 343         pci_read_config_byte(fbd_dev, DIMM_THRTLOW, &i7300_idle_thrtlow_saved);
 344         pci_read_config_dword(fbd_dev, DIMM_MC, &i7300_idle_mc_saved);
 345         /*
 346          * Make sure we have Global Throttling Window Mode set to have a
 347          * "short" window. This (mostly) works around an issue where
 348          * throttling persists until the end of the global throttling window
 349          * size. On the tested system, this was resulting in a maximum of
 350          * 64 ms to exit throttling (average 32 ms). The actual numbers
 351          * depends on system frequencies. Setting the short window reduces
 352          * this by a factor of 4096.
 353          *
 354          * We will only do this only if the system is set for
 355          * unlimited-activations while in open-loop throttling (i.e., when
 356          * Global Activation Throttle Limit is zero).
 357          */
 358         pci_read_config_byte(fbd_dev, DIMM_GBLACT, &gblactlm);
 359         dprintk("thrtctl_saved = 0x%02x, thrtlow_saved = 0x%02x\n",
 360                 i7300_idle_thrtctl_saved,
 361                 i7300_idle_thrtlow_saved);
 362         dprintk("mc_saved = 0x%08x, gblactlm = 0x%02x\n",
 363                 i7300_idle_mc_saved,
 364                 gblactlm);
 365         if (gblactlm == 0) {
 366                 new_mc_val = i7300_idle_mc_saved | DIMM_GTW_MODE;
 367                 pci_write_config_dword(fbd_dev, DIMM_MC, new_mc_val);
 368                 return 0;
 369         } else {
 370                 dprintk("could not set GTW_MODE = 1 (OLTT enabled)\n");
 371                 return -ENODEV;
 372         }
 373 }
 374
 375 /* Restore DIMM thermal throttle configuration */
 376 static void i7300_idle_thrt_restore(void)
 377 {
 378         pci_write_config_dword(fbd_dev, DIMM_MC, i7300_idle_mc_saved);
 379         pci_write_config_byte(fbd_dev, DIMM_THRTLOW, i7300_idle_thrtlow_saved);
 380         pci_write_config_byte(fbd_dev, DIMM_THRTCTL, i7300_idle_thrtctl_saved);
 381 }
 382
 383 /* Enable DIMM thermal throttling */
 384 static void i7300_idle_start(void)
 385 {
 386         u8 new_ctl;
 387         u8 limit;
 388
 389         new_ctl = i7300_idle_thrtctl_saved & ~DIMM_THRTCTL_THRMHUNT;
 390         pci_write_config_byte(fbd_dev, DIMM_THRTCTL, new_ctl);
 391
 392         limit = i7300_idle_thrtlowlm;
 393         if (unlikely(limit > MAX_THRTLWLIMIT))
 394                 limit = MAX_THRTLWLIMIT;
 395
 396         pci_write_config_byte(fbd_dev, DIMM_THRTLOW, limit);
 397
 398         new_ctl = i7300_idle_thrtctl_saved | DIMM_THRTCTL_THRMHUNT;
 399         pci_write_config_byte(fbd_dev, DIMM_THRTCTL, new_ctl);
 400 }
 401
 402 /* Disable DIMM thermal throttling */
 403 static void i7300_idle_stop(void)
 404 {
 405         u8 new_ctl;
 406         u8 got_ctl;
 407
 408         new_ctl = i7300_idle_thrtctl_saved & ~DIMM_THRTCTL_THRMHUNT;
 409         pci_write_config_byte(fbd_dev, DIMM_THRTCTL, new_ctl);
 410
 411         pci_write_config_byte(fbd_dev, DIMM_THRTLOW, i7300_idle_thrtlow_saved);
 412         pci_write_config_byte(fbd_dev, DIMM_THRTCTL, i7300_idle_thrtctl_saved);
 413         pci_read_config_byte(fbd_dev, DIMM_THRTCTL, &got_ctl);
 414         WARN_ON_ONCE(got_ctl != i7300_idle_thrtctl_saved);
 415 }
 416
 417
 418 /*
 419  * i7300_avg_duration_check()
 420  * return 0 if the decaying average of recent idle durations is
 421  * more than DURATION_THRESHOLD_US
 422  */
 423 static int i7300_avg_duration_check(void)
 424 {
 425         if (avg_idle_us >= DURATION_THRESHOLD_US)
 426                 return 0;
 427
 428 #ifdef DEBUG
 429         past_skip++;
 430 #endif
 431         return 1;
 432 }
 433
 434 /* Idle notifier to look at idle CPUs */
 435 static int i7300_idle_notifier(struct notifier_block *nb, unsigned long val,
 436                                 void *data)
 437 {
 438         unsigned long flags;
 439         ktime_t now_ktime;
 440         static ktime_t idle_begin_time;
 441         static int time_init = 1;
 442
 443         if (!i7300_idle_thrtlowlm)
 444                 return 0;
 445
 446         if (unlikely(time_init)) {
 447                 time_init = 0;
 448                 idle_begin_time = ktime_get();
 449         }
 450
 451         spin_lock_irqsave(&i7300_idle_lock, flags);
 452         if (val == IDLE_START) {
 453
 454                 cpu_set(smp_processor_id(), idle_cpumask);
 455
 456                 if (cpus_weight(idle_cpumask) != num_online_cpus())
 457                         goto end;
 458
 459                 now_ktime = ktime_get();
 460                 idle_begin_time = now_ktime;
 461
 462                 if (i7300_avg_duration_check())
 463                         goto end;
 464
 465                 i7300_idle_active = 1;
 466                 total_starts++;
 467                 start_ktime = now_ktime;
 468
 469                 i7300_idle_start();
 470                 i7300_idle_ioat_start();
 471
 472         } else if (val == IDLE_END) {
 473                 cpu_clear(smp_processor_id(), idle_cpumask);
 474                 if (cpus_weight(idle_cpumask) == (num_online_cpus() - 1)) {
 475                         /* First CPU coming out of idle */
 476                         u64 idle_duration_us;
 477
 478                         now_ktime = ktime_get();
 479
 480                         idle_duration_us = ktime_to_us(ktime_sub
 481                                                 (now_ktime, idle_begin_time));
 482
 483                         avg_idle_us =
 484                                 ((100 - DURATION_WEIGHT_PCT) * avg_idle_us +
 485                                  DURATION_WEIGHT_PCT * idle_duration_us) / 100;
 486
 487                         if (i7300_idle_active) {
 488                                 ktime_t idle_ktime;
 489
 490                                 idle_ktime = ktime_sub(now_ktime, start_ktime);
 491                                 total_us += ktime_to_us(idle_ktime);
 492
 493                                 i7300_idle_ioat_stop();
 494                                 i7300_idle_stop();
 495                                 i7300_idle_active = 0;
 496                         }
 497                 }
 498         }
 499 end:
 500         spin_unlock_irqrestore(&i7300_idle_lock, flags);
 501         return 0;
 502 }
 503
 504 static struct notifier_block i7300_idle_nb = {
 505         .notifier_call = i7300_idle_notifier,
 506 };
 507
 508 /*
 509  * I/O AT controls (PCI bus 0 device 8 function 0)
 510  * DIMM controls (PCI bus 0 device 16 function 1)
 511  */
 512 #define IOAT_BUS 0
 513 #define IOAT_DEVFN PCI_DEVFN(8, 0)
 514 #define MEMCTL_BUS 0
 515 #define MEMCTL_DEVFN PCI_DEVFN(16, 1)
 516
 517 struct fbd_ioat {
 518         unsigned int vendor;
 519         unsigned int ioat_dev;
 520 };
 521
 522 /*
 523  * The i5000 chip-set has the same hooks as the i7300
 524  * but support is disabled by default because this driver
 525  * has not been validated on that platform.
 526  */
 527 #define SUPPORT_I5000 0
 528
 529 static const struct fbd_ioat fbd_ioat_list[] = {
 530         {PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_IOAT_CNB},
 531 #if SUPPORT_I5000
 532         {PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_IOAT},
 533 #endif
 534         {0, 0}
 535 };
 536
 537 /* table of devices that work with this driver */
 538 static const struct pci_device_id pci_tbl[] = {
 539         { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_FBD_CNB) },
 540 #if SUPPORT_I5000
 541         { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_5000_ERR) },
 542 #endif
 543         { } /* Terminating entry */
 544 };
 545
 546 MODULE_DEVICE_TABLE(pci, pci_tbl);
 547
 548 /* Check for known platforms with I/O-AT */
 549 static int __init i7300_idle_platform_probe(void)
 550 {
 551         int i;
 552
 553         fbd_dev = pci_get_bus_and_slot(MEMCTL_BUS, MEMCTL_DEVFN);
 554         if (!fbd_dev)
 555                 return -ENODEV;
 556
 557         for (i = 0; pci_tbl[i].vendor != 0; i++) {
 558                 if (fbd_dev->vendor == pci_tbl[i].vendor &&
 559                     fbd_dev->device == pci_tbl[i].device) {
 560                         break;
 561                 }
 562         }
 563         if (pci_tbl[i].vendor == 0)
 564                 return -ENODEV;
 565
 566         ioat_dev = pci_get_bus_and_slot(IOAT_BUS, IOAT_DEVFN);
 567         if (!ioat_dev)
 568                 return -ENODEV;
 569
 570         for (i = 0; fbd_ioat_list[i].vendor != 0; i++) {
 571                 if (ioat_dev->vendor == fbd_ioat_list[i].vendor &&
 572                     ioat_dev->device == fbd_ioat_list[i].ioat_dev) {
 573                         return 0;
 574                 }
 575         }
 576         return -ENODEV;
 577 }
 578
 579 int stats_open_generic(struct inode *inode, struct file *fp)
 580 {
 581         fp->private_data = inode->i_private;
 582         return 0;
 583 }
 584
 585 static ssize_t stats_read_ul(struct file *fp, char __user *ubuf, size_t count,
 586                                 loff_t *off)
 587 {
 588         unsigned long *p = fp->private_data;
 589         char buf[32];
 590         int len;
 591
 592         len = snprintf(buf, 32, "%lu\n", *p);
 593         return simple_read_from_buffer(ubuf, count, off, buf, len);
 594 }
 595
 596 static const struct file_operations idle_fops = {
 597         .open   = stats_open_generic,
 598         .read   = stats_read_ul,
 599 };
 600
 601 struct debugfs_file_info {
 602         void *ptr;
 603         char name[32];
 604         struct dentry *file;
 605 } debugfs_file_list[] = {
 606                                 {&total_starts, "total_starts", NULL},
 607                                 {&total_us, "total_us", NULL},
 608 #ifdef DEBUG
 609                                 {&past_skip, "past_skip", NULL},
 610 #endif
 611                                 {NULL, "", NULL}
 612                         };
 613
 614 static int __init i7300_idle_init(void)
 615 {
 616         spin_lock_init(&i7300_idle_lock);
 617         cpus_clear(idle_cpumask);
 618         total_us = 0;
 619
 620         if (i7300_idle_platform_probe())
 621                 return -ENODEV;
 622
 623         if (i7300_idle_thrt_save())
 624                 return -ENODEV;
 625
 626         if (i7300_idle_ioat_init())
 627                 return -ENODEV;
 628
 629         debugfs_dir = debugfs_create_dir("i7300_idle", NULL);
 630         if (debugfs_dir) {
 631                 int i = 0;
 632
 633                 while (debugfs_file_list[i].ptr != NULL) {
 634                         debugfs_file_list[i].file = debugfs_create_file(
 635                                         debugfs_file_list[i].name,
 636                                         S_IRUSR,
 637                                         debugfs_dir,
 638                                         debugfs_file_list[i].ptr,
 639                                         &idle_fops);
 640                         i++;
 641                 }
 642         }
 643
 644         idle_notifier_register(&i7300_idle_nb);
 645
 646         printk(KERN_INFO "i7300_idle: loaded v%s\n", I7300_IDLE_DRIVER_VERSION);
 647         return 0;
 648 }
 649
 650 static void __exit i7300_idle_exit(void)
 651 {
 652         idle_notifier_unregister(&i7300_idle_nb);
 653
 654         if (debugfs_dir) {
 655                 int i = 0;
 656
 657                 while (debugfs_file_list[i].file != NULL) {
 658                         debugfs_remove(debugfs_file_list[i].file);
 659                         i++;
 660                 }
 661
 662                 debugfs_remove(debugfs_dir);
 663         }
 664         i7300_idle_thrt_restore();
 665         i7300_idle_ioat_exit();
 666 }
 667
 668 module_init(i7300_idle_init);
 669 module_exit(i7300_idle_exit);
 670
 671 MODULE_AUTHOR("Andy Henroid <andrew.d.henroid@intel.com>");
 672 MODULE_DESCRIPTION("Intel Chipset DIMM Idle Power Saving Driver v"
 673                         I7300_IDLE_DRIVER_VERSION);
 674 MODULE_LICENSE("GPL");