1/*
2 * Intel e7xxx Memory Controller kernel module
3 * (C) 2003 Linux Networx (http://lnxi.com)
4 * This file may be distributed under the terms of the
5 * GNU General Public License.
6 *
7 * See "enum e7xxx_chips" below for supported chipsets
8 *
9 * Written by Thayne Harbaugh
10 * Based on work by Dan Hollis <goemon at anime dot net> and others.
11 * http://www.anime.net/~goemon/linux-ecc/
12 *
13 * Datasheet:
14 * http://www.intel.com/content/www/us/en/chipsets/e7501-chipset-memory-controller-hub-datasheet.html
15 *
16 * Contributors:
17 * Eric Biederman (Linux Networx)
18 * Tom Zimmerman (Linux Networx)
19 * Jim Garlick (Lawrence Livermore National Labs)
20 * Dave Peterson (Lawrence Livermore National Labs)
21 * That One Guy (Some other place)
22 * Wang Zhenyu (intel.com)
23 *
24 * $Id: edac_e7xxx.c,v 1.5.2.9 2005/10/05 00:43:44 dsp_llnl Exp $
25 *
26 */
27
28#include <linux/module.h>
29#include <linux/init.h>
30#include <linux/pci.h>
31#include <linux/pci_ids.h>
32#include <linux/edac.h>
33#include "edac_module.h"
34
35#define EDAC_MOD_STR "e7xxx_edac"
36
37#define e7xxx_printk(level, fmt, arg...) \
38 edac_printk(level, "e7xxx", fmt, ##arg)
39
40#define e7xxx_mc_printk(mci, level, fmt, arg...) \
41 edac_mc_chipset_printk(mci, level, "e7xxx", fmt, ##arg)
42
43#ifndef PCI_DEVICE_ID_INTEL_7205_0
44#define PCI_DEVICE_ID_INTEL_7205_0 0x255d
45#endif /* PCI_DEVICE_ID_INTEL_7205_0 */
46
47#ifndef PCI_DEVICE_ID_INTEL_7205_1_ERR
48#define PCI_DEVICE_ID_INTEL_7205_1_ERR 0x2551
49#endif /* PCI_DEVICE_ID_INTEL_7205_1_ERR */
50
51#ifndef PCI_DEVICE_ID_INTEL_7500_0
52#define PCI_DEVICE_ID_INTEL_7500_0 0x2540
53#endif /* PCI_DEVICE_ID_INTEL_7500_0 */
54
55#ifndef PCI_DEVICE_ID_INTEL_7500_1_ERR
56#define PCI_DEVICE_ID_INTEL_7500_1_ERR 0x2541
57#endif /* PCI_DEVICE_ID_INTEL_7500_1_ERR */
58
59#ifndef PCI_DEVICE_ID_INTEL_7501_0
60#define PCI_DEVICE_ID_INTEL_7501_0 0x254c
61#endif /* PCI_DEVICE_ID_INTEL_7501_0 */
62
63#ifndef PCI_DEVICE_ID_INTEL_7501_1_ERR
64#define PCI_DEVICE_ID_INTEL_7501_1_ERR 0x2541
65#endif /* PCI_DEVICE_ID_INTEL_7501_1_ERR */
66
67#ifndef PCI_DEVICE_ID_INTEL_7505_0
68#define PCI_DEVICE_ID_INTEL_7505_0 0x2550
69#endif /* PCI_DEVICE_ID_INTEL_7505_0 */
70
71#ifndef PCI_DEVICE_ID_INTEL_7505_1_ERR
72#define PCI_DEVICE_ID_INTEL_7505_1_ERR 0x2551
73#endif /* PCI_DEVICE_ID_INTEL_7505_1_ERR */
74
75#define E7XXX_NR_CSROWS 8 /* number of csrows */
76#define E7XXX_NR_DIMMS 8 /* 2 channels, 4 dimms/channel */
77
78/* E7XXX register addresses - device 0 function 0 */
79#define E7XXX_DRB 0x60 /* DRAM row boundary register (8b) */
80#define E7XXX_DRA 0x70 /* DRAM row attribute register (8b) */
81 /*
82 * 31 Device width row 7 0=x8 1=x4
83 * 27 Device width row 6
84 * 23 Device width row 5
85 * 19 Device width row 4
86 * 15 Device width row 3
87 * 11 Device width row 2
88 * 7 Device width row 1
89 * 3 Device width row 0
90 */
91#define E7XXX_DRC 0x7C /* DRAM controller mode reg (32b) */
92 /*
93 * 22 Number channels 0=1,1=2
94 * 19:18 DRB Granularity 32/64MB
95 */
96#define E7XXX_TOLM 0xC4 /* DRAM top of low memory reg (16b) */
97#define E7XXX_REMAPBASE 0xC6 /* DRAM remap base address reg (16b) */
98#define E7XXX_REMAPLIMIT 0xC8 /* DRAM remap limit address reg (16b) */
99
100/* E7XXX register addresses - device 0 function 1 */
101#define E7XXX_DRAM_FERR 0x80 /* DRAM first error register (8b) */
102#define E7XXX_DRAM_NERR 0x82 /* DRAM next error register (8b) */
103#define E7XXX_DRAM_CELOG_ADD 0xA0 /* DRAM first correctable memory */
104 /* error address register (32b) */
105 /*
106 * 31:28 Reserved
107 * 27:6 CE address (4k block 33:12)
108 * 5:0 Reserved
109 */
110#define E7XXX_DRAM_UELOG_ADD 0xB0 /* DRAM first uncorrectable memory */
111 /* error address register (32b) */
112 /*
113 * 31:28 Reserved
114 * 27:6 CE address (4k block 33:12)
115 * 5:0 Reserved
116 */
117#define E7XXX_DRAM_CELOG_SYNDROME 0xD0 /* DRAM first correctable memory */
118 /* error syndrome register (16b) */
119
120enum e7xxx_chips {
121 E7500 = 0,
122 E7501,
123 E7505,
124 E7205,
125};
126
127struct e7xxx_pvt {
128 struct pci_dev *bridge_ck;
129 u32 tolm;
130 u32 remapbase;
131 u32 remaplimit;
132 const struct e7xxx_dev_info *dev_info;
133};
134
135struct e7xxx_dev_info {
136 u16 err_dev;
137 const char *ctl_name;
138};
139
140struct e7xxx_error_info {
141 u8 dram_ferr;
142 u8 dram_nerr;
143 u32 dram_celog_add;
144 u16 dram_celog_syndrome;
145 u32 dram_uelog_add;
146};
147
148static struct edac_pci_ctl_info *e7xxx_pci;
149
150static const struct e7xxx_dev_info e7xxx_devs[] = {
151 [E7500] = {
152 .err_dev = PCI_DEVICE_ID_INTEL_7500_1_ERR,
153 .ctl_name = "E7500"},
154 [E7501] = {
155 .err_dev = PCI_DEVICE_ID_INTEL_7501_1_ERR,
156 .ctl_name = "E7501"},
157 [E7505] = {
158 .err_dev = PCI_DEVICE_ID_INTEL_7505_1_ERR,
159 .ctl_name = "E7505"},
160 [E7205] = {
161 .err_dev = PCI_DEVICE_ID_INTEL_7205_1_ERR,
162 .ctl_name = "E7205"},
163};
164
165/* FIXME - is this valid for both SECDED and S4ECD4ED? */
166static inline int e7xxx_find_channel(u16 syndrome)
167{
168 edac_dbg(3, "\n");
169
170 if ((syndrome & 0xff00) == 0)
171 return 0;
172
173 if ((syndrome & 0x00ff) == 0)
174 return 1;
175
176 if ((syndrome & 0xf000) == 0 || (syndrome & 0x0f00) == 0)
177 return 0;
178
179 return 1;
180}
181
182static unsigned long ctl_page_to_phys(struct mem_ctl_info *mci,
183 unsigned long page)
184{
185 u32 remap;
186 struct e7xxx_pvt *pvt = (struct e7xxx_pvt *)mci->pvt_info;
187
188 edac_dbg(3, "\n");
189
190 if ((page < pvt->tolm) ||
191 ((page >= 0x100000) && (page < pvt->remapbase)))
192 return page;
193
194 remap = (page - pvt->tolm) + pvt->remapbase;
195
196 if (remap < pvt->remaplimit)
197 return remap;
198
199 e7xxx_printk(KERN_ERR, "Invalid page %lx - out of range\n", page);
200 return pvt->tolm - 1;
201}
202
203static void process_ce(struct mem_ctl_info *mci, struct e7xxx_error_info *info)
204{
205 u32 error_1b, page;
206 u16 syndrome;
207 int row;
208 int channel;
209
210 edac_dbg(3, "\n");
211 /* read the error address */
212 error_1b = info->dram_celog_add;
213 /* FIXME - should use PAGE_SHIFT */
214 page = error_1b >> 6; /* convert the address to 4k page */
215 /* read the syndrome */
216 syndrome = info->dram_celog_syndrome;
217 /* FIXME - check for -1 */
218 row = edac_mc_find_csrow_by_page(mci, page);
219 /* convert syndrome to channel */
220 channel = e7xxx_find_channel(syndrome);
221 edac_mc_handle_error(type: HW_EVENT_ERR_CORRECTED, mci, error_count: 1, page_frame_number: page, offset_in_page: 0, syndrome,
222 top_layer: row, mid_layer: channel, low_layer: -1, msg: "e7xxx CE", other_detail: "");
223}
224
225static void process_ce_no_info(struct mem_ctl_info *mci)
226{
227 edac_dbg(3, "\n");
228 edac_mc_handle_error(type: HW_EVENT_ERR_CORRECTED, mci, error_count: 1, page_frame_number: 0, offset_in_page: 0, syndrome: 0, top_layer: -1, mid_layer: -1, low_layer: -1,
229 msg: "e7xxx CE log register overflow", other_detail: "");
230}
231
232static void process_ue(struct mem_ctl_info *mci, struct e7xxx_error_info *info)
233{
234 u32 error_2b, block_page;
235 int row;
236
237 edac_dbg(3, "\n");
238 /* read the error address */
239 error_2b = info->dram_uelog_add;
240 /* FIXME - should use PAGE_SHIFT */
241 block_page = error_2b >> 6; /* convert to 4k address */
242 row = edac_mc_find_csrow_by_page(mci, page: block_page);
243
244 edac_mc_handle_error(type: HW_EVENT_ERR_UNCORRECTED, mci, error_count: 1, page_frame_number: block_page, offset_in_page: 0, syndrome: 0,
245 top_layer: row, mid_layer: -1, low_layer: -1, msg: "e7xxx UE", other_detail: "");
246}
247
248static void process_ue_no_info(struct mem_ctl_info *mci)
249{
250 edac_dbg(3, "\n");
251
252 edac_mc_handle_error(type: HW_EVENT_ERR_UNCORRECTED, mci, error_count: 1, page_frame_number: 0, offset_in_page: 0, syndrome: 0, top_layer: -1, mid_layer: -1, low_layer: -1,
253 msg: "e7xxx UE log register overflow", other_detail: "");
254}
255
256static void e7xxx_get_error_info(struct mem_ctl_info *mci,
257 struct e7xxx_error_info *info)
258{
259 struct e7xxx_pvt *pvt;
260
261 pvt = (struct e7xxx_pvt *)mci->pvt_info;
262 pci_read_config_byte(dev: pvt->bridge_ck, E7XXX_DRAM_FERR, val: &info->dram_ferr);
263 pci_read_config_byte(dev: pvt->bridge_ck, E7XXX_DRAM_NERR, val: &info->dram_nerr);
264
265 if ((info->dram_ferr & 1) || (info->dram_nerr & 1)) {
266 pci_read_config_dword(dev: pvt->bridge_ck, E7XXX_DRAM_CELOG_ADD,
267 val: &info->dram_celog_add);
268 pci_read_config_word(dev: pvt->bridge_ck,
269 E7XXX_DRAM_CELOG_SYNDROME,
270 val: &info->dram_celog_syndrome);
271 }
272
273 if ((info->dram_ferr & 2) || (info->dram_nerr & 2))
274 pci_read_config_dword(dev: pvt->bridge_ck, E7XXX_DRAM_UELOG_ADD,
275 val: &info->dram_uelog_add);
276
277 if (info->dram_ferr & 3)
278 pci_write_bits8(pdev: pvt->bridge_ck, E7XXX_DRAM_FERR, value: 0x03, mask: 0x03);
279
280 if (info->dram_nerr & 3)
281 pci_write_bits8(pdev: pvt->bridge_ck, E7XXX_DRAM_NERR, value: 0x03, mask: 0x03);
282}
283
284static int e7xxx_process_error_info(struct mem_ctl_info *mci,
285 struct e7xxx_error_info *info,
286 int handle_errors)
287{
288 int error_found;
289
290 error_found = 0;
291
292 /* decode and report errors */
293 if (info->dram_ferr & 1) { /* check first error correctable */
294 error_found = 1;
295
296 if (handle_errors)
297 process_ce(mci, info);
298 }
299
300 if (info->dram_ferr & 2) { /* check first error uncorrectable */
301 error_found = 1;
302
303 if (handle_errors)
304 process_ue(mci, info);
305 }
306
307 if (info->dram_nerr & 1) { /* check next error correctable */
308 error_found = 1;
309
310 if (handle_errors) {
311 if (info->dram_ferr & 1)
312 process_ce_no_info(mci);
313 else
314 process_ce(mci, info);
315 }
316 }
317
318 if (info->dram_nerr & 2) { /* check next error uncorrectable */
319 error_found = 1;
320
321 if (handle_errors) {
322 if (info->dram_ferr & 2)
323 process_ue_no_info(mci);
324 else
325 process_ue(mci, info);
326 }
327 }
328
329 return error_found;
330}
331
332static void e7xxx_check(struct mem_ctl_info *mci)
333{
334 struct e7xxx_error_info info;
335
336 e7xxx_get_error_info(mci, info: &info);
337 e7xxx_process_error_info(mci, info: &info, handle_errors: 1);
338}
339
340/* Return 1 if dual channel mode is active. Else return 0. */
341static inline int dual_channel_active(u32 drc, int dev_idx)
342{
343 return (dev_idx == E7501) ? ((drc >> 22) & 0x1) : 1;
344}
345
346/* Return DRB granularity (0=32mb, 1=64mb). */
347static inline int drb_granularity(u32 drc, int dev_idx)
348{
349 /* only e7501 can be single channel */
350 return (dev_idx == E7501) ? ((drc >> 18) & 0x3) : 1;
351}
352
353static void e7xxx_init_csrows(struct mem_ctl_info *mci, struct pci_dev *pdev,
354 int dev_idx, u32 drc)
355{
356 unsigned long last_cumul_size;
357 int index, j;
358 u8 value;
359 u32 dra, cumul_size, nr_pages;
360 int drc_chan, drc_drbg, drc_ddim, mem_dev;
361 struct csrow_info *csrow;
362 struct dimm_info *dimm;
363 enum edac_type edac_mode;
364
365 pci_read_config_dword(dev: pdev, E7XXX_DRA, val: &dra);
366 drc_chan = dual_channel_active(drc, dev_idx);
367 drc_drbg = drb_granularity(drc, dev_idx);
368 drc_ddim = (drc >> 20) & 0x3;
369 last_cumul_size = 0;
370
371 /* The dram row boundary (DRB) reg values are boundary address
372 * for each DRAM row with a granularity of 32 or 64MB (single/dual
373 * channel operation). DRB regs are cumulative; therefore DRB7 will
374 * contain the total memory contained in all eight rows.
375 */
376 for (index = 0; index < mci->nr_csrows; index++) {
377 /* mem_dev 0=x8, 1=x4 */
378 mem_dev = (dra >> (index * 4 + 3)) & 0x1;
379 csrow = mci->csrows[index];
380
381 pci_read_config_byte(dev: pdev, E7XXX_DRB + index, val: &value);
382 /* convert a 64 or 32 MiB DRB to a page size. */
383 cumul_size = value << (25 + drc_drbg - PAGE_SHIFT);
384 edac_dbg(3, "(%d) cumul_size 0x%x\n", index, cumul_size);
385 if (cumul_size == last_cumul_size)
386 continue; /* not populated */
387
388 csrow->first_page = last_cumul_size;
389 csrow->last_page = cumul_size - 1;
390 nr_pages = cumul_size - last_cumul_size;
391 last_cumul_size = cumul_size;
392
393 /*
394 * if single channel or x8 devices then SECDED
395 * if dual channel and x4 then S4ECD4ED
396 */
397 if (drc_ddim) {
398 if (drc_chan && mem_dev) {
399 edac_mode = EDAC_S4ECD4ED;
400 mci->edac_cap |= EDAC_FLAG_S4ECD4ED;
401 } else {
402 edac_mode = EDAC_SECDED;
403 mci->edac_cap |= EDAC_FLAG_SECDED;
404 }
405 } else
406 edac_mode = EDAC_NONE;
407
408 for (j = 0; j < drc_chan + 1; j++) {
409 dimm = csrow->channels[j]->dimm;
410
411 dimm->nr_pages = nr_pages / (drc_chan + 1);
412 dimm->grain = 1 << 12; /* 4KiB - resolution of CELOG */
413 dimm->mtype = MEM_RDDR; /* only one type supported */
414 dimm->dtype = mem_dev ? DEV_X4 : DEV_X8;
415 dimm->edac_mode = edac_mode;
416 }
417 }
418}
419
420static int e7xxx_probe1(struct pci_dev *pdev, int dev_idx)
421{
422 u16 pci_data;
423 struct mem_ctl_info *mci = NULL;
424 struct edac_mc_layer layers[2];
425 struct e7xxx_pvt *pvt = NULL;
426 u32 drc;
427 int drc_chan;
428 struct e7xxx_error_info discard;
429
430 edac_dbg(0, "mci\n");
431
432 pci_read_config_dword(dev: pdev, E7XXX_DRC, val: &drc);
433
434 drc_chan = dual_channel_active(drc, dev_idx);
435 /*
436 * According with the datasheet, this device has a maximum of
437 * 4 DIMMS per channel, either single-rank or dual-rank. So, the
438 * total amount of dimms is 8 (E7XXX_NR_DIMMS).
439 * That means that the DIMM is mapped as CSROWs, and the channel
440 * will map the rank. So, an error to either channel should be
441 * attributed to the same dimm.
442 */
443 layers[0].type = EDAC_MC_LAYER_CHIP_SELECT;
444 layers[0].size = E7XXX_NR_CSROWS;
445 layers[0].is_virt_csrow = true;
446 layers[1].type = EDAC_MC_LAYER_CHANNEL;
447 layers[1].size = drc_chan + 1;
448 layers[1].is_virt_csrow = false;
449 mci = edac_mc_alloc(mc_num: 0, ARRAY_SIZE(layers), layers, sz_pvt: sizeof(*pvt));
450 if (mci == NULL)
451 return -ENOMEM;
452
453 edac_dbg(3, "init mci\n");
454 mci->mtype_cap = MEM_FLAG_RDDR;
455 mci->edac_ctl_cap = EDAC_FLAG_NONE | EDAC_FLAG_SECDED |
456 EDAC_FLAG_S4ECD4ED;
457 /* FIXME - what if different memory types are in different csrows? */
458 mci->mod_name = EDAC_MOD_STR;
459 mci->pdev = &pdev->dev;
460 edac_dbg(3, "init pvt\n");
461 pvt = (struct e7xxx_pvt *)mci->pvt_info;
462 pvt->dev_info = &e7xxx_devs[dev_idx];
463 pvt->bridge_ck = pci_get_device(PCI_VENDOR_ID_INTEL,
464 device: pvt->dev_info->err_dev, from: pvt->bridge_ck);
465
466 if (!pvt->bridge_ck) {
467 e7xxx_printk(KERN_ERR, "error reporting device not found:"
468 "vendor %x device 0x%x (broken BIOS?)\n",
469 PCI_VENDOR_ID_INTEL, e7xxx_devs[dev_idx].err_dev);
470 goto fail0;
471 }
472
473 edac_dbg(3, "more mci init\n");
474 mci->ctl_name = pvt->dev_info->ctl_name;
475 mci->dev_name = pci_name(pdev);
476 mci->edac_check = e7xxx_check;
477 mci->ctl_page_to_phys = ctl_page_to_phys;
478 e7xxx_init_csrows(mci, pdev, dev_idx, drc);
479 mci->edac_cap |= EDAC_FLAG_NONE;
480 edac_dbg(3, "tolm, remapbase, remaplimit\n");
481 /* load the top of low memory, remap base, and remap limit vars */
482 pci_read_config_word(dev: pdev, E7XXX_TOLM, val: &pci_data);
483 pvt->tolm = ((u32) pci_data) << 4;
484 pci_read_config_word(dev: pdev, E7XXX_REMAPBASE, val: &pci_data);
485 pvt->remapbase = ((u32) pci_data) << 14;
486 pci_read_config_word(dev: pdev, E7XXX_REMAPLIMIT, val: &pci_data);
487 pvt->remaplimit = ((u32) pci_data) << 14;
488 e7xxx_printk(KERN_INFO,
489 "tolm = %x, remapbase = %x, remaplimit = %x\n", pvt->tolm,
490 pvt->remapbase, pvt->remaplimit);
491
492 /* clear any pending errors, or initial state bits */
493 e7xxx_get_error_info(mci, info: &discard);
494
495 /* Here we assume that we will never see multiple instances of this
496 * type of memory controller. The ID is therefore hardcoded to 0.
497 */
498 if (edac_mc_add_mc(mci)) {
499 edac_dbg(3, "failed edac_mc_add_mc()\n");
500 goto fail1;
501 }
502
503 /* allocating generic PCI control info */
504 e7xxx_pci = edac_pci_create_generic_ctl(dev: &pdev->dev, EDAC_MOD_STR);
505 if (!e7xxx_pci) {
506 printk(KERN_WARNING
507 "%s(): Unable to create PCI control\n",
508 __func__);
509 printk(KERN_WARNING
510 "%s(): PCI error report via EDAC not setup\n",
511 __func__);
512 }
513
514 /* get this far and it's successful */
515 edac_dbg(3, "success\n");
516 return 0;
517
518fail1:
519 pci_dev_put(dev: pvt->bridge_ck);
520
521fail0:
522 edac_mc_free(mci);
523
524 return -ENODEV;
525}
526
527/* returns count (>= 0), or negative on error */
528static int e7xxx_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
529{
530 edac_dbg(0, "\n");
531
532 /* wake up and enable device */
533 return pci_enable_device(dev: pdev) ?
534 -EIO : e7xxx_probe1(pdev, dev_idx: ent->driver_data);
535}
536
537static void e7xxx_remove_one(struct pci_dev *pdev)
538{
539 struct mem_ctl_info *mci;
540 struct e7xxx_pvt *pvt;
541
542 edac_dbg(0, "\n");
543
544 if (e7xxx_pci)
545 edac_pci_release_generic_ctl(pci: e7xxx_pci);
546
547 if ((mci = edac_mc_del_mc(dev: &pdev->dev)) == NULL)
548 return;
549
550 pvt = (struct e7xxx_pvt *)mci->pvt_info;
551 pci_dev_put(dev: pvt->bridge_ck);
552 edac_mc_free(mci);
553}
554
555static const struct pci_device_id e7xxx_pci_tbl[] = {
556 {
557 PCI_VEND_DEV(INTEL, 7205_0), PCI_ANY_ID, PCI_ANY_ID, 0, 0,
558 E7205},
559 {
560 PCI_VEND_DEV(INTEL, 7500_0), PCI_ANY_ID, PCI_ANY_ID, 0, 0,
561 E7500},
562 {
563 PCI_VEND_DEV(INTEL, 7501_0), PCI_ANY_ID, PCI_ANY_ID, 0, 0,
564 E7501},
565 {
566 PCI_VEND_DEV(INTEL, 7505_0), PCI_ANY_ID, PCI_ANY_ID, 0, 0,
567 E7505},
568 {
569 0,
570 } /* 0 terminated list. */
571};
572
573MODULE_DEVICE_TABLE(pci, e7xxx_pci_tbl);
574
575static struct pci_driver e7xxx_driver = {
576 .name = EDAC_MOD_STR,
577 .probe = e7xxx_init_one,
578 .remove = e7xxx_remove_one,
579 .id_table = e7xxx_pci_tbl,
580};
581
582static int __init e7xxx_init(void)
583{
584 /* Ensure that the OPSTATE is set correctly for POLL or NMI */
585 opstate_init();
586
587 return pci_register_driver(&e7xxx_driver);
588}
589
590static void __exit e7xxx_exit(void)
591{
592 pci_unregister_driver(dev: &e7xxx_driver);
593}
594
595module_init(e7xxx_init);
596module_exit(e7xxx_exit);
597
598MODULE_LICENSE("GPL");
599MODULE_AUTHOR("Linux Networx (http://lnxi.com) Thayne Harbaugh et al");
600MODULE_DESCRIPTION("MC support for Intel e7xxx memory controllers");
601module_param(edac_op_state, int, 0444);
602MODULE_PARM_DESC(edac_op_state, "EDAC Error Reporting state: 0=Poll,1=NMI");
603

source code of linux/drivers/edac/e7xxx_edac.c