drivers/edac/i82875p_edac.c - kernel/msm-4.19 - Gitiles

 /*
  * Intel D82875P Memory Controller kernel module
  * (C) 2003 Linux Networx (http://lnxi.com)
  * This file may be distributed under the terms of the
  * GNU General Public License.
  *
  * Written by Thayne Harbaugh
  * Contributors:
  *	Wang Zhenyu at intel.com
  *
  * $Id: edac_i82875p.c,v 1.5.2.11 2005/10/05 00:43:44 dsp_llnl Exp $
  *
  * Note: E7210 appears same as D82875P - zhenyu.z.wang at intel.com
  */


 #include <linux/config.h>
 #include <linux/module.h>
 #include <linux/init.h>

 #include <linux/pci.h>
 #include <linux/pci_ids.h>

 #include <linux/slab.h>

 #include "edac_mc.h"


 #define i82875p_printk(level, fmt, arg...) \
     edac_printk(level, "i82875p", fmt, ##arg)


 #define i82875p_mc_printk(mci, level, fmt, arg...) \
     edac_mc_chipset_printk(mci, level, "i82875p", fmt, ##arg)


 #ifndef PCI_DEVICE_ID_INTEL_82875_0
 #define PCI_DEVICE_ID_INTEL_82875_0	0x2578
 #endif				/* PCI_DEVICE_ID_INTEL_82875_0 */

 #ifndef PCI_DEVICE_ID_INTEL_82875_6
 #define PCI_DEVICE_ID_INTEL_82875_6	0x257e
 #endif				/* PCI_DEVICE_ID_INTEL_82875_6 */


 /* four csrows in dual channel, eight in single channel */
 #define I82875P_NR_CSROWS(nr_chans) (8/(nr_chans))


 /* Intel 82875p register addresses - device 0 function 0 - DRAM Controller */
 #define I82875P_EAP		0x58	/* Error Address Pointer (32b)
 					 *
 					 * 31:12 block address
 					 * 11:0  reserved
 					 */

 #define I82875P_DERRSYN		0x5c	/* DRAM Error Syndrome (8b)
 					 *
 					 *  7:0  DRAM ECC Syndrome
 					 */

 #define I82875P_DES		0x5d	/* DRAM Error Status (8b)
 					 *
 					 *  7:1  reserved
 					 *  0    Error channel 0/1
 					 */

 #define I82875P_ERRSTS		0xc8	/* Error Status Register (16b)
 					 *
 					 * 15:10 reserved
 					 *  9    non-DRAM lock error (ndlock)
 					 *  8    Sftwr Generated SMI
 					 *  7    ECC UE
 					 *  6    reserved
 					 *  5    MCH detects unimplemented cycle
 					 *  4    AGP access outside GA
 					 *  3    Invalid AGP access
 					 *  2    Invalid GA translation table
 					 *  1    Unsupported AGP command
 					 *  0    ECC CE
 					 */

 #define I82875P_ERRCMD		0xca	/* Error Command (16b)
 					 *
 					 * 15:10 reserved
 					 *  9    SERR on non-DRAM lock
 					 *  8    SERR on ECC UE
 					 *  7    SERR on ECC CE
 					 *  6    target abort on high exception
 					 *  5    detect unimplemented cyc
 					 *  4    AGP access outside of GA
 					 *  3    SERR on invalid AGP access
 					 *  2    invalid translation table
 					 *  1    SERR on unsupported AGP command
 					 *  0    reserved
 					 */


 /* Intel 82875p register addresses - device 6 function 0 - DRAM Controller */
 #define I82875P_PCICMD6		0x04	/* PCI Command Register (16b)
 					 *
 					 * 15:10 reserved
 					 *  9    fast back-to-back - ro 0
 					 *  8    SERR enable - ro 0
 					 *  7    addr/data stepping - ro 0
 					 *  6    parity err enable - ro 0
 					 *  5    VGA palette snoop - ro 0
 					 *  4    mem wr & invalidate - ro 0
 					 *  3    special cycle - ro 0
 					 *  2    bus master - ro 0
 					 *  1    mem access dev6 - 0(dis),1(en)
 					 *  0    IO access dev3 - 0(dis),1(en)
 					 */

 #define I82875P_BAR6		0x10	/* Mem Delays Base ADDR Reg (32b)
 					 *
 					 * 31:12 mem base addr [31:12]
 					 * 11:4  address mask - ro 0
 					 *  3    prefetchable - ro 0(non),1(pre)
 					 *  2:1  mem type - ro 0
 					 *  0    mem space - ro 0
 					 */

 /* Intel 82875p MMIO register space - device 0 function 0 - MMR space */

 #define I82875P_DRB_SHIFT 26	/* 64MiB grain */
 #define I82875P_DRB		0x00	/* DRAM Row Boundary (8b x 8)
 					 *
 					 *  7    reserved
 					 *  6:0  64MiB row boundary addr
 					 */

 #define I82875P_DRA		0x10	/* DRAM Row Attribute (4b x 8)
 					 *
 					 *  7    reserved
 					 *  6:4  row attr row 1
 					 *  3    reserved
 					 *  2:0  row attr row 0
 					 *
 					 * 000 =  4KiB
 					 * 001 =  8KiB
 					 * 010 = 16KiB
 					 * 011 = 32KiB
 					 */

 #define I82875P_DRC		0x68	/* DRAM Controller Mode (32b)
 					 *
 					 * 31:30 reserved
 					 * 29    init complete
 					 * 28:23 reserved
 					 * 22:21 nr chan 00=1,01=2
 					 * 20    reserved
 					 * 19:18 Data Integ Mode 00=none,01=ecc
 					 * 17:11 reserved
 					 * 10:8  refresh mode
 					 *  7    reserved
 					 *  6:4  mode select
 					 *  3:2  reserved
 					 *  1:0  DRAM type 01=DDR
 					 */


 enum i82875p_chips {
 	I82875P = 0,
 };


 struct i82875p_pvt {
 	struct pci_dev *ovrfl_pdev;
 	void __iomem *ovrfl_window;
 };


 struct i82875p_dev_info {
 	const char *ctl_name;
 };


 struct i82875p_error_info {
 	u16 errsts;
 	u32 eap;
 	u8 des;
 	u8 derrsyn;
 	u16 errsts2;
 };


 static const struct i82875p_dev_info i82875p_devs[] = {
 	[I82875P] = {
 		     .ctl_name = "i82875p"},
 };

 static struct pci_dev *mci_pdev = NULL;	/* init dev: in case that AGP code
 					   has already registered driver */
 static int i82875p_registered = 1;

 static void i82875p_get_error_info (struct mem_ctl_info *mci,
 		struct i82875p_error_info *info)
 {
 	/*
 	 * This is a mess because there is no atomic way to read all the
 	 * registers at once and the registers can transition from CE being
 	 * overwritten by UE.
 	 */
 	pci_read_config_word(mci->pdev, I82875P_ERRSTS, &info->errsts);
 	pci_read_config_dword(mci->pdev, I82875P_EAP, &info->eap);
 	pci_read_config_byte(mci->pdev, I82875P_DES, &info->des);
 	pci_read_config_byte(mci->pdev, I82875P_DERRSYN, &info->derrsyn);
 	pci_read_config_word(mci->pdev, I82875P_ERRSTS, &info->errsts2);

 	pci_write_bits16(mci->pdev, I82875P_ERRSTS, 0x0081, 0x0081);

 	/*
 	 * If the error is the same then we can for both reads then
 	 * the first set of reads is valid.  If there is a change then
 	 * there is a CE no info and the second set of reads is valid
 	 * and should be UE info.
 	 */
 	if (!(info->errsts2 & 0x0081))
 		return;
 	if ((info->errsts ^ info->errsts2) & 0x0081) {
 		pci_read_config_dword(mci->pdev, I82875P_EAP, &info->eap);
 		pci_read_config_byte(mci->pdev, I82875P_DES, &info->des);
 		pci_read_config_byte(mci->pdev, I82875P_DERRSYN,
 		    &info->derrsyn);
 	}
 }

 static int i82875p_process_error_info (struct mem_ctl_info *mci,
 		struct i82875p_error_info *info, int handle_errors)
 {
 	int row, multi_chan;

 	multi_chan = mci->csrows[0].nr_channels - 1;

 	if (!(info->errsts2 & 0x0081))
 		return 0;

 	if (!handle_errors)
 		return 1;

 	if ((info->errsts ^ info->errsts2) & 0x0081) {
 		edac_mc_handle_ce_no_info(mci, "UE overwrote CE");
 		info->errsts = info->errsts2;
 	}

 	info->eap >>= PAGE_SHIFT;
 	row = edac_mc_find_csrow_by_page(mci, info->eap);

 	if (info->errsts & 0x0080)
 		edac_mc_handle_ue(mci, info->eap, 0, row, "i82875p UE");
 	else
 		edac_mc_handle_ce(mci, info->eap, 0, info->derrsyn, row,
 				       multi_chan ? (info->des & 0x1) : 0,
 				       "i82875p CE");

 	return 1;
 }


 static void i82875p_check(struct mem_ctl_info *mci)
 {
 	struct i82875p_error_info info;

 	debugf1("MC%d: %s()\n", mci->mc_idx, __func__);
 	i82875p_get_error_info(mci, &info);
 	i82875p_process_error_info(mci, &info, 1);
 }


 #ifdef CONFIG_PROC_FS
 extern int pci_proc_attach_device(struct pci_dev *);
 #endif

 static int i82875p_probe1(struct pci_dev *pdev, int dev_idx)
 {
 	int rc = -ENODEV;
 	int index;
 	struct mem_ctl_info *mci = NULL;
 	struct i82875p_pvt *pvt = NULL;
 	unsigned long last_cumul_size;
 	struct pci_dev *ovrfl_pdev;
 	void __iomem *ovrfl_window = NULL;

 	u32 drc;
 	u32 drc_chan;		/* Number of channels 0=1chan,1=2chan */
 	u32 nr_chans;
 	u32 drc_ddim;		/* DRAM Data Integrity Mode 0=none,2=edac */
 	struct i82875p_error_info discard;

 	debugf0("%s()\n", __func__);

 	ovrfl_pdev = pci_get_device(PCI_VEND_DEV(INTEL, 82875_6), NULL);

 	if (!ovrfl_pdev) {
 		/*
 		 * Intel tells BIOS developers to hide device 6 which
 		 * configures the overflow device access containing
 		 * the DRBs - this is where we expose device 6.
 		 * http://www.x86-secret.com/articles/tweak/pat/patsecrets-2.htm
 		 */
 		pci_write_bits8(pdev, 0xf4, 0x2, 0x2);
 		ovrfl_pdev =
 		    pci_scan_single_device(pdev->bus, PCI_DEVFN(6, 0));
 		if (!ovrfl_pdev)
 			return -ENODEV;
 	}
 #ifdef CONFIG_PROC_FS
 	if (!ovrfl_pdev->procent && pci_proc_attach_device(ovrfl_pdev)) {
 		i82875p_printk(KERN_ERR,
 			       "%s(): Failed to attach overflow device\n",
 			       __func__);
 		return -ENODEV;
 	}
 #endif				/* CONFIG_PROC_FS */
 	if (pci_enable_device(ovrfl_pdev)) {
 		i82875p_printk(KERN_ERR,
 			       "%s(): Failed to enable overflow device\n",
 			       __func__);
 		return -ENODEV;
 	}

 	if (pci_request_regions(ovrfl_pdev, pci_name(ovrfl_pdev))) {
 #ifdef CORRECT_BIOS
 		goto fail0;
 #endif
 	}
 	/* cache is irrelevant for PCI bus reads/writes */
 	ovrfl_window = ioremap_nocache(pci_resource_start(ovrfl_pdev, 0),
 				       pci_resource_len(ovrfl_pdev, 0));

 	if (!ovrfl_window) {
 		i82875p_printk(KERN_ERR, "%s(): Failed to ioremap bar6\n",
 			       __func__);
 		goto fail1;
 	}

 	/* need to find out the number of channels */
 	drc = readl(ovrfl_window + I82875P_DRC);
 	drc_chan = ((drc >> 21) & 0x1);
 	nr_chans = drc_chan + 1;
 	drc_ddim = (drc >> 18) & 0x1;

 	mci = edac_mc_alloc(sizeof(*pvt), I82875P_NR_CSROWS(nr_chans),
 				 nr_chans);

 	if (!mci) {
 		rc = -ENOMEM;
 		goto fail2;
 	}

 	debugf3("%s(): init mci\n", __func__);

 	mci->pdev = pdev;
 	mci->mtype_cap = MEM_FLAG_DDR;

 	mci->edac_ctl_cap = EDAC_FLAG_NONE | EDAC_FLAG_SECDED;
 	mci->edac_cap = EDAC_FLAG_UNKNOWN;
 	/* adjust FLAGS */

 	mci->mod_name = EDAC_MOD_STR;
 	mci->mod_ver = "$Revision: 1.5.2.11 $";
 	mci->ctl_name = i82875p_devs[dev_idx].ctl_name;
 	mci->edac_check = i82875p_check;
 	mci->ctl_page_to_phys = NULL;

 	debugf3("%s(): init pvt\n", __func__);

 	pvt = (struct i82875p_pvt *) mci->pvt_info;
 	pvt->ovrfl_pdev = ovrfl_pdev;
 	pvt->ovrfl_window = ovrfl_window;

 	/*
 	 * The dram row boundary (DRB) reg values are boundary address
 	 * for each DRAM row with a granularity of 32 or 64MB (single/dual
 	 * channel operation).  DRB regs are cumulative; therefore DRB7 will
 	 * contain the total memory contained in all eight rows.
 	 */
 	for (last_cumul_size = index = 0; index < mci->nr_csrows; index++) {
 		u8 value;
 		u32 cumul_size;
 		struct csrow_info *csrow = &mci->csrows[index];

 		value = readb(ovrfl_window + I82875P_DRB + index);
 		cumul_size = value << (I82875P_DRB_SHIFT - PAGE_SHIFT);
 		debugf3("%s(): (%d) cumul_size 0x%x\n", __func__, index,
 			cumul_size);
 		if (cumul_size == last_cumul_size)
 			continue;	/* not populated */

 		csrow->first_page = last_cumul_size;
 		csrow->last_page = cumul_size - 1;
 		csrow->nr_pages = cumul_size - last_cumul_size;
 		last_cumul_size = cumul_size;
 		csrow->grain = 1 << 12;	/* I82875P_EAP has 4KiB reolution */
 		csrow->mtype = MEM_DDR;
 		csrow->dtype = DEV_UNKNOWN;
 		csrow->edac_mode = drc_ddim ? EDAC_SECDED : EDAC_NONE;
 	}

 	i82875p_get_error_info(mci, &discard);  /* clear counters */

 	if (edac_mc_add_mc(mci)) {
 		debugf3("%s(): failed edac_mc_add_mc()\n", __func__);
 		goto fail3;
 	}

 	/* get this far and it's successful */
 	debugf3("%s(): success\n", __func__);
 	return 0;

 fail3:
 	edac_mc_free(mci);

 fail2:
 	iounmap(ovrfl_window);

 fail1:
 	pci_release_regions(ovrfl_pdev);

 #ifdef CORRECT_BIOS
 fail0:
 #endif
 	pci_disable_device(ovrfl_pdev);
 	/* NOTE: the ovrfl proc entry and pci_dev are intentionally left */
 	return rc;
 }


 /* returns count (>= 0), or negative on error */
 static int __devinit i82875p_init_one(struct pci_dev *pdev,
 				      const struct pci_device_id *ent)
 {
 	int rc;

 	debugf0("%s()\n", __func__);

 	i82875p_printk(KERN_INFO, "i82875p init one\n");
 	if(pci_enable_device(pdev) < 0)
 		return -EIO;
 	rc = i82875p_probe1(pdev, ent->driver_data);
 	if (mci_pdev == NULL)
 		mci_pdev = pci_dev_get(pdev);
 	return rc;
 }


 static void __devexit i82875p_remove_one(struct pci_dev *pdev)
 {
 	struct mem_ctl_info *mci;
 	struct i82875p_pvt *pvt = NULL;

 	debugf0("%s()\n", __func__);

 	if ((mci = edac_mc_find_mci_by_pdev(pdev)) == NULL)
 		return;

 	pvt = (struct i82875p_pvt *) mci->pvt_info;
 	if (pvt->ovrfl_window)
 		iounmap(pvt->ovrfl_window);

 	if (pvt->ovrfl_pdev) {
 #ifdef CORRECT_BIOS
 		pci_release_regions(pvt->ovrfl_pdev);
 #endif				/*CORRECT_BIOS */
 		pci_disable_device(pvt->ovrfl_pdev);
 		pci_dev_put(pvt->ovrfl_pdev);
 	}

 	if (edac_mc_del_mc(mci))
 		return;

 	edac_mc_free(mci);
 }


 static const struct pci_device_id i82875p_pci_tbl[] __devinitdata = {
 	{PCI_VEND_DEV(INTEL, 82875_0), PCI_ANY_ID, PCI_ANY_ID, 0, 0,
 	 I82875P},
 	{0,}			/* 0 terminated list. */
 };

 MODULE_DEVICE_TABLE(pci, i82875p_pci_tbl);


 static struct pci_driver i82875p_driver = {
 	.name = EDAC_MOD_STR,
 	.probe = i82875p_init_one,
 	.remove = __devexit_p(i82875p_remove_one),
 	.id_table = i82875p_pci_tbl,
 };


 static int __init i82875p_init(void)
 {
 	int pci_rc;

 	debugf3("%s()\n", __func__);
 	pci_rc = pci_register_driver(&i82875p_driver);
 	if (pci_rc < 0)
 		goto fail0;
 	if (mci_pdev == NULL) {
 		mci_pdev =
 		    pci_get_device(PCI_VENDOR_ID_INTEL,
 				   PCI_DEVICE_ID_INTEL_82875_0, NULL);
 		if (!mci_pdev) {
 			debugf0("875p pci_get_device fail\n");
 			pci_rc = -ENODEV;
 			goto fail1;
 		}
 		pci_rc = i82875p_init_one(mci_pdev, i82875p_pci_tbl);
 		if (pci_rc < 0) {
 			debugf0("875p init fail\n");
 			pci_rc = -ENODEV;
 			goto fail1;
 		}
 	}
 	return 0;

 fail1:
 	pci_unregister_driver(&i82875p_driver);

 fail0:
 	if (mci_pdev != NULL)
 		pci_dev_put(mci_pdev);

 	return pci_rc;
 }


 static void __exit i82875p_exit(void)
 {
 	debugf3("%s()\n", __func__);

 	pci_unregister_driver(&i82875p_driver);
 	if (!i82875p_registered) {
 		i82875p_remove_one(mci_pdev);
 		pci_dev_put(mci_pdev);
 	}
 }


 module_init(i82875p_init);
 module_exit(i82875p_exit);


 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Linux Networx (http://lnxi.com) Thayne Harbaugh");
 MODULE_DESCRIPTION("MC support for Intel 82875 memory hub controllers");
	/*
	* Intel D82875P Memory Controller kernel module
	* (C) 2003 Linux Networx (http://lnxi.com)
	* This file may be distributed under the terms of the
	* GNU General Public License.
	*
	* Written by Thayne Harbaugh
	* Contributors:
	* Wang Zhenyu at intel.com
	*
	* $Id: edac_i82875p.c,v 1.5.2.11 2005/10/05 00:43:44 dsp_llnl Exp $
	*
	* Note: E7210 appears same as D82875P - zhenyu.z.wang at intel.com
	*/


	#include <linux/config.h>
	#include <linux/module.h>
	#include <linux/init.h>

	#include <linux/pci.h>
	#include <linux/pci_ids.h>

	#include <linux/slab.h>

	#include "edac_mc.h"


	#define i82875p_printk(level, fmt, arg...) \
	edac_printk(level, "i82875p", fmt, ##arg)


	#define i82875p_mc_printk(mci, level, fmt, arg...) \
	edac_mc_chipset_printk(mci, level, "i82875p", fmt, ##arg)


	#ifndef PCI_DEVICE_ID_INTEL_82875_0
	#define PCI_DEVICE_ID_INTEL_82875_0 0x2578
	#endif /* PCI_DEVICE_ID_INTEL_82875_0 */

	#ifndef PCI_DEVICE_ID_INTEL_82875_6
	#define PCI_DEVICE_ID_INTEL_82875_6 0x257e
	#endif /* PCI_DEVICE_ID_INTEL_82875_6 */


	/* four csrows in dual channel, eight in single channel */
	#define I82875P_NR_CSROWS(nr_chans) (8/(nr_chans))


	/* Intel 82875p register addresses - device 0 function 0 - DRAM Controller */
	#define I82875P_EAP 0x58 /* Error Address Pointer (32b)
	*
	* 31:12 block address
	* 11:0 reserved
	*/

	#define I82875P_DERRSYN 0x5c /* DRAM Error Syndrome (8b)
	*
	* 7:0 DRAM ECC Syndrome
	*/

	#define I82875P_DES 0x5d /* DRAM Error Status (8b)
	*
	* 7:1 reserved
	* 0 Error channel 0/1
	*/

	#define I82875P_ERRSTS 0xc8 /* Error Status Register (16b)
	*
	* 15:10 reserved
	* 9 non-DRAM lock error (ndlock)
	* 8 Sftwr Generated SMI
	* 7 ECC UE
	* 6 reserved
	* 5 MCH detects unimplemented cycle
	* 4 AGP access outside GA
	* 3 Invalid AGP access
	* 2 Invalid GA translation table
	* 1 Unsupported AGP command
	* 0 ECC CE
	*/

	#define I82875P_ERRCMD 0xca /* Error Command (16b)
	*
	* 15:10 reserved
	* 9 SERR on non-DRAM lock
	* 8 SERR on ECC UE
	* 7 SERR on ECC CE
	* 6 target abort on high exception
	* 5 detect unimplemented cyc
	* 4 AGP access outside of GA
	* 3 SERR on invalid AGP access
	* 2 invalid translation table
	* 1 SERR on unsupported AGP command
	* 0 reserved
	*/


	/* Intel 82875p register addresses - device 6 function 0 - DRAM Controller */
	#define I82875P_PCICMD6 0x04 /* PCI Command Register (16b)
	*
	* 15:10 reserved
	* 9 fast back-to-back - ro 0
	* 8 SERR enable - ro 0
	* 7 addr/data stepping - ro 0
	* 6 parity err enable - ro 0
	* 5 VGA palette snoop - ro 0
	* 4 mem wr & invalidate - ro 0
	* 3 special cycle - ro 0
	* 2 bus master - ro 0
	* 1 mem access dev6 - 0(dis),1(en)
	* 0 IO access dev3 - 0(dis),1(en)
	*/

	#define I82875P_BAR6 0x10 /* Mem Delays Base ADDR Reg (32b)
	*
	* 31:12 mem base addr [31:12]
	* 11:4 address mask - ro 0
	* 3 prefetchable - ro 0(non),1(pre)
	* 2:1 mem type - ro 0
	* 0 mem space - ro 0
	*/

	/* Intel 82875p MMIO register space - device 0 function 0 - MMR space */

	#define I82875P_DRB_SHIFT 26 /* 64MiB grain */
	#define I82875P_DRB 0x00 /* DRAM Row Boundary (8b x 8)
	*
	* 7 reserved
	* 6:0 64MiB row boundary addr
	*/

	#define I82875P_DRA 0x10 /* DRAM Row Attribute (4b x 8)
	*
	* 7 reserved
	* 6:4 row attr row 1
	* 3 reserved
	* 2:0 row attr row 0
	*
	* 000 = 4KiB
	* 001 = 8KiB
	* 010 = 16KiB
	* 011 = 32KiB
	*/

	#define I82875P_DRC 0x68 /* DRAM Controller Mode (32b)
	*
	* 31:30 reserved
	* 29 init complete
	* 28:23 reserved
	* 22:21 nr chan 00=1,01=2
	* 20 reserved
	* 19:18 Data Integ Mode 00=none,01=ecc
	* 17:11 reserved
	* 10:8 refresh mode
	* 7 reserved
	* 6:4 mode select
	* 3:2 reserved
	* 1:0 DRAM type 01=DDR
	*/


	enum i82875p_chips {
	I82875P = 0,
	};


	struct i82875p_pvt {
	struct pci_dev *ovrfl_pdev;
	void __iomem *ovrfl_window;
	};


	struct i82875p_dev_info {
	const char *ctl_name;
	};


	struct i82875p_error_info {
	u16 errsts;
	u32 eap;
	u8 des;
	u8 derrsyn;
	u16 errsts2;
	};


	static const struct i82875p_dev_info i82875p_devs[] = {
	[I82875P] = {
	.ctl_name = "i82875p"},
	};

	static struct pci_dev mci_pdev = NULL; / init dev: in case that AGP code
	has already registered driver */
	static int i82875p_registered = 1;

	static void i82875p_get_error_info (struct mem_ctl_info *mci,
	struct i82875p_error_info *info)
	{
	/*
	* This is a mess because there is no atomic way to read all the
	* registers at once and the registers can transition from CE being
	* overwritten by UE.
	*/
	pci_read_config_word(mci->pdev, I82875P_ERRSTS, &info->errsts);
	pci_read_config_dword(mci->pdev, I82875P_EAP, &info->eap);
	pci_read_config_byte(mci->pdev, I82875P_DES, &info->des);
	pci_read_config_byte(mci->pdev, I82875P_DERRSYN, &info->derrsyn);
	pci_read_config_word(mci->pdev, I82875P_ERRSTS, &info->errsts2);

	pci_write_bits16(mci->pdev, I82875P_ERRSTS, 0x0081, 0x0081);

	/*
	* If the error is the same then we can for both reads then
	* the first set of reads is valid. If there is a change then
	* there is a CE no info and the second set of reads is valid
	* and should be UE info.
	*/
	if (!(info->errsts2 & 0x0081))
	return;
	if ((info->errsts ^ info->errsts2) & 0x0081) {
	pci_read_config_dword(mci->pdev, I82875P_EAP, &info->eap);
	pci_read_config_byte(mci->pdev, I82875P_DES, &info->des);
	pci_read_config_byte(mci->pdev, I82875P_DERRSYN,
	&info->derrsyn);
	}
	}

	static int i82875p_process_error_info (struct mem_ctl_info *mci,
	struct i82875p_error_info *info, int handle_errors)
	{
	int row, multi_chan;

	multi_chan = mci->csrows[0].nr_channels - 1;

	if (!(info->errsts2 & 0x0081))
	return 0;

	if (!handle_errors)
	return 1;

	if ((info->errsts ^ info->errsts2) & 0x0081) {
	edac_mc_handle_ce_no_info(mci, "UE overwrote CE");
	info->errsts = info->errsts2;
	}

	info->eap >>= PAGE_SHIFT;
	row = edac_mc_find_csrow_by_page(mci, info->eap);

	if (info->errsts & 0x0080)
	edac_mc_handle_ue(mci, info->eap, 0, row, "i82875p UE");
	else
	edac_mc_handle_ce(mci, info->eap, 0, info->derrsyn, row,
	multi_chan ? (info->des & 0x1) : 0,
	"i82875p CE");

	return 1;
	}


	static void i82875p_check(struct mem_ctl_info *mci)
	{
	struct i82875p_error_info info;

	debugf1("MC%d: %s()\n", mci->mc_idx, __func__);
	i82875p_get_error_info(mci, &info);
	i82875p_process_error_info(mci, &info, 1);
	}


	#ifdef CONFIG_PROC_FS
	extern int pci_proc_attach_device(struct pci_dev *);
	#endif

	static int i82875p_probe1(struct pci_dev *pdev, int dev_idx)
	{
	int rc = -ENODEV;
	int index;
	struct mem_ctl_info *mci = NULL;
	struct i82875p_pvt *pvt = NULL;
	unsigned long last_cumul_size;
	struct pci_dev *ovrfl_pdev;
	void __iomem *ovrfl_window = NULL;

	u32 drc;
	u32 drc_chan; /* Number of channels 0=1chan,1=2chan */
	u32 nr_chans;
	u32 drc_ddim; /* DRAM Data Integrity Mode 0=none,2=edac */
	struct i82875p_error_info discard;

	debugf0("%s()\n", __func__);

	ovrfl_pdev = pci_get_device(PCI_VEND_DEV(INTEL, 82875_6), NULL);

	if (!ovrfl_pdev) {
	/*
	* Intel tells BIOS developers to hide device 6 which
	* configures the overflow device access containing
	* the DRBs - this is where we expose device 6.
	* http://www.x86-secret.com/articles/tweak/pat/patsecrets-2.htm
	*/
	pci_write_bits8(pdev, 0xf4, 0x2, 0x2);
	ovrfl_pdev =
	pci_scan_single_device(pdev->bus, PCI_DEVFN(6, 0));
	if (!ovrfl_pdev)
	return -ENODEV;
	}
	#ifdef CONFIG_PROC_FS
	if (!ovrfl_pdev->procent && pci_proc_attach_device(ovrfl_pdev)) {
	i82875p_printk(KERN_ERR,
	"%s(): Failed to attach overflow device\n",
	__func__);
	return -ENODEV;
	}
	#endif /* CONFIG_PROC_FS */
	if (pci_enable_device(ovrfl_pdev)) {
	i82875p_printk(KERN_ERR,
	"%s(): Failed to enable overflow device\n",
	__func__);
	return -ENODEV;
	}

	if (pci_request_regions(ovrfl_pdev, pci_name(ovrfl_pdev))) {
	#ifdef CORRECT_BIOS
	goto fail0;
	#endif
	}
	/* cache is irrelevant for PCI bus reads/writes */
	ovrfl_window = ioremap_nocache(pci_resource_start(ovrfl_pdev, 0),
	pci_resource_len(ovrfl_pdev, 0));

	if (!ovrfl_window) {
	i82875p_printk(KERN_ERR, "%s(): Failed to ioremap bar6\n",
	__func__);
	goto fail1;
	}

	/* need to find out the number of channels */
	drc = readl(ovrfl_window + I82875P_DRC);
	drc_chan = ((drc >> 21) & 0x1);
	nr_chans = drc_chan + 1;
	drc_ddim = (drc >> 18) & 0x1;

	mci = edac_mc_alloc(sizeof(*pvt), I82875P_NR_CSROWS(nr_chans),
	nr_chans);

	if (!mci) {
	rc = -ENOMEM;
	goto fail2;
	}

	debugf3("%s(): init mci\n", __func__);

	mci->pdev = pdev;
	mci->mtype_cap = MEM_FLAG_DDR;

	mci->edac_ctl_cap = EDAC_FLAG_NONE \| EDAC_FLAG_SECDED;
	mci->edac_cap = EDAC_FLAG_UNKNOWN;
	/* adjust FLAGS */

	mci->mod_name = EDAC_MOD_STR;
	mci->mod_ver = "$Revision: 1.5.2.11 $";
	mci->ctl_name = i82875p_devs[dev_idx].ctl_name;
	mci->edac_check = i82875p_check;
	mci->ctl_page_to_phys = NULL;

	debugf3("%s(): init pvt\n", __func__);

	pvt = (struct i82875p_pvt *) mci->pvt_info;
	pvt->ovrfl_pdev = ovrfl_pdev;
	pvt->ovrfl_window = ovrfl_window;

	/*
	* The dram row boundary (DRB) reg values are boundary address
	* for each DRAM row with a granularity of 32 or 64MB (single/dual
	* channel operation). DRB regs are cumulative; therefore DRB7 will
	* contain the total memory contained in all eight rows.
	*/
	for (last_cumul_size = index = 0; index < mci->nr_csrows; index++) {
	u8 value;
	u32 cumul_size;
	struct csrow_info *csrow = &mci->csrows[index];

	value = readb(ovrfl_window + I82875P_DRB + index);
	cumul_size = value << (I82875P_DRB_SHIFT - PAGE_SHIFT);
	debugf3("%s(): (%d) cumul_size 0x%x\n", __func__, index,
	cumul_size);
	if (cumul_size == last_cumul_size)
	continue; /* not populated */

	csrow->first_page = last_cumul_size;
	csrow->last_page = cumul_size - 1;
	csrow->nr_pages = cumul_size - last_cumul_size;
	last_cumul_size = cumul_size;
	csrow->grain = 1 << 12; /* I82875P_EAP has 4KiB reolution */
	csrow->mtype = MEM_DDR;
	csrow->dtype = DEV_UNKNOWN;
	csrow->edac_mode = drc_ddim ? EDAC_SECDED : EDAC_NONE;
	}

	i82875p_get_error_info(mci, &discard); /* clear counters */

	if (edac_mc_add_mc(mci)) {
	debugf3("%s(): failed edac_mc_add_mc()\n", __func__);
	goto fail3;
	}

	/* get this far and it's successful */
	debugf3("%s(): success\n", __func__);
	return 0;

	fail3:
	edac_mc_free(mci);

	fail2:
	iounmap(ovrfl_window);

	fail1:
	pci_release_regions(ovrfl_pdev);

	#ifdef CORRECT_BIOS
	fail0:
	#endif
	pci_disable_device(ovrfl_pdev);
	/* NOTE: the ovrfl proc entry and pci_dev are intentionally left */
	return rc;
	}


	/* returns count (>= 0), or negative on error */
	static int __devinit i82875p_init_one(struct pci_dev *pdev,
	const struct pci_device_id *ent)
	{
	int rc;

	debugf0("%s()\n", __func__);

	i82875p_printk(KERN_INFO, "i82875p init one\n");
	if(pci_enable_device(pdev) < 0)
	return -EIO;
	rc = i82875p_probe1(pdev, ent->driver_data);
	if (mci_pdev == NULL)
	mci_pdev = pci_dev_get(pdev);
	return rc;
	}


	static void __devexit i82875p_remove_one(struct pci_dev *pdev)
	{
	struct mem_ctl_info *mci;
	struct i82875p_pvt *pvt = NULL;

	debugf0("%s()\n", __func__);

	if ((mci = edac_mc_find_mci_by_pdev(pdev)) == NULL)
	return;

	pvt = (struct i82875p_pvt *) mci->pvt_info;
	if (pvt->ovrfl_window)
	iounmap(pvt->ovrfl_window);

	if (pvt->ovrfl_pdev) {
	#ifdef CORRECT_BIOS
	pci_release_regions(pvt->ovrfl_pdev);
	#endif /CORRECT_BIOS /
	pci_disable_device(pvt->ovrfl_pdev);
	pci_dev_put(pvt->ovrfl_pdev);
	}

	if (edac_mc_del_mc(mci))
	return;

	edac_mc_free(mci);
	}


	static const struct pci_device_id i82875p_pci_tbl[] __devinitdata = {
	{PCI_VEND_DEV(INTEL, 82875_0), PCI_ANY_ID, PCI_ANY_ID, 0, 0,
	I82875P},
	{0,} /* 0 terminated list. */
	};

	MODULE_DEVICE_TABLE(pci, i82875p_pci_tbl);


	static struct pci_driver i82875p_driver = {
	.name = EDAC_MOD_STR,
	.probe = i82875p_init_one,
	.remove = __devexit_p(i82875p_remove_one),
	.id_table = i82875p_pci_tbl,
	};


	static int __init i82875p_init(void)
	{
	int pci_rc;

	debugf3("%s()\n", __func__);
	pci_rc = pci_register_driver(&i82875p_driver);
	if (pci_rc < 0)
	goto fail0;
	if (mci_pdev == NULL) {
	mci_pdev =
	pci_get_device(PCI_VENDOR_ID_INTEL,
	PCI_DEVICE_ID_INTEL_82875_0, NULL);
	if (!mci_pdev) {
	debugf0("875p pci_get_device fail\n");
	pci_rc = -ENODEV;
	goto fail1;
	}
	pci_rc = i82875p_init_one(mci_pdev, i82875p_pci_tbl);
	if (pci_rc < 0) {
	debugf0("875p init fail\n");
	pci_rc = -ENODEV;
	goto fail1;
	}
	}
	return 0;

	fail1:
	pci_unregister_driver(&i82875p_driver);

	fail0:
	if (mci_pdev != NULL)
	pci_dev_put(mci_pdev);

	return pci_rc;
	}


	static void __exit i82875p_exit(void)
	{
	debugf3("%s()\n", __func__);

	pci_unregister_driver(&i82875p_driver);
	if (!i82875p_registered) {
	i82875p_remove_one(mci_pdev);
	pci_dev_put(mci_pdev);
	}
	}


	module_init(i82875p_init);
	module_exit(i82875p_exit);


	MODULE_LICENSE("GPL");
	MODULE_AUTHOR("Linux Networx (http://lnxi.com) Thayne Harbaugh");
	MODULE_DESCRIPTION("MC support for Intel 82875 memory hub controllers");