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/module.h>
 #include <linux/init.h>
 #include <linux/pci.h>
 #include <linux/pci_ids.h>
 #include <linux/edac.h>
 #include "edac_module.h"

 #define I82875P_REVISION	" Ver: 2.0.2"
 #define EDAC_MOD_STR		"i82875p_edac"

 #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_DIMMS		8
 #define I82875P_NR_CSROWS(nr_chans)	(I82875P_NR_DIMMS / (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;	/* init dev: in case that AGP code has
 					 * already registered driver
 					 */

 static struct edac_pci_ctl_info *i82875p_pci;

 static void i82875p_get_error_info(struct mem_ctl_info *mci,
 				struct i82875p_error_info *info)
 {
 	struct pci_dev *pdev;

 	pdev = to_pci_dev(mci->pdev);

 	/*
 	 * 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(pdev, I82875P_ERRSTS, &info->errsts);

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

 	pci_read_config_dword(pdev, I82875P_EAP, &info->eap);
 	pci_read_config_byte(pdev, I82875P_DES, &info->des);
 	pci_read_config_byte(pdev, I82875P_DERRSYN, &info->derrsyn);
 	pci_read_config_word(pdev, I82875P_ERRSTS, &info->errsts2);

 	/*
 	 * 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->errsts ^ info->errsts2) & 0x0081) {
 		pci_read_config_dword(pdev, I82875P_EAP, &info->eap);
 		pci_read_config_byte(pdev, I82875P_DES, &info->des);
 		pci_read_config_byte(pdev, I82875P_DERRSYN, &info->derrsyn);
 	}

 	pci_write_bits16(pdev, I82875P_ERRSTS, 0x0081, 0x0081);
 }

 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->errsts & 0x0081))
 		return 0;

 	if (!handle_errors)
 		return 1;

 	if ((info->errsts ^ info->errsts2) & 0x0081) {
 		edac_mc_handle_error(HW_EVENT_ERR_UNCORRECTED, mci, 1, 0, 0, 0,
 				     -1, -1, -1,
 				     "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_error(HW_EVENT_ERR_UNCORRECTED, mci, 1,
 				     info->eap, 0, 0,
 				     row, -1, -1,
 				     "i82875p UE", "");
 	else
 		edac_mc_handle_error(HW_EVENT_ERR_CORRECTED, mci, 1,
 				     info->eap, 0, info->derrsyn,
 				     row, multi_chan ? (info->des & 0x1) : 0,
 				     -1, "i82875p CE", "");

 	return 1;
 }

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

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

 /* Return 0 on success or 1 on failure. */
 static int i82875p_setup_overfl_dev(struct pci_dev *pdev,
 				struct pci_dev **ovrfl_pdev,
 				void __iomem **ovrfl_window)
 {
 	struct pci_dev *dev;
 	void __iomem *window;

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

 	if (dev == NULL) {
 		/* 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);
 		dev = pci_scan_single_device(pdev->bus, PCI_DEVFN(6, 0));

 		if (dev == NULL)
 			return 1;

 		pci_bus_assign_resources(dev->bus);
 		pci_bus_add_device(dev);
 	}

 	*ovrfl_pdev = dev;

 	if (pci_enable_device(dev)) {
 		i82875p_printk(KERN_ERR, "%s(): Failed to enable overflow "
 			"device\n", __func__);
 		return 1;
 	}

 	if (pci_request_regions(dev, pci_name(dev))) {
 #ifdef CORRECT_BIOS
 		goto fail0;
 #endif
 	}

 	/* cache is irrelevant for PCI bus reads/writes */
 	window = pci_ioremap_bar(dev, 0);
 	if (window == NULL) {
 		i82875p_printk(KERN_ERR, "%s(): Failed to ioremap bar6\n",
 			__func__);
 		goto fail1;
 	}

 	*ovrfl_window = window;
 	return 0;

 fail1:
 	pci_release_regions(dev);

 #ifdef CORRECT_BIOS
 fail0:
 	pci_disable_device(dev);
 #endif
 	/* NOTE: the ovrfl proc entry and pci_dev are intentionally left */
 	return 1;
 }

 /* Return 1 if dual channel mode is active.  Else return 0. */
 static inline int dual_channel_active(u32 drc)
 {
 	return (drc >> 21) & 0x1;
 }

 static void i82875p_init_csrows(struct mem_ctl_info *mci,
 				struct pci_dev *pdev,
 				void __iomem * ovrfl_window, u32 drc)
 {
 	struct csrow_info *csrow;
 	struct dimm_info *dimm;
 	unsigned nr_chans = dual_channel_active(drc) + 1;
 	unsigned long last_cumul_size;
 	u8 value;
 	u32 drc_ddim;		/* DRAM Data Integrity Mode 0=none,2=edac */
 	u32 cumul_size, nr_pages;
 	int index, j;

 	drc_ddim = (drc >> 18) & 0x1;
 	last_cumul_size = 0;

 	/* 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 (index = 0; index < mci->nr_csrows; index++) {
 		csrow = mci->csrows[index];

 		value = readb(ovrfl_window + I82875P_DRB + index);
 		cumul_size = value << (I82875P_DRB_SHIFT - PAGE_SHIFT);
 		edac_dbg(3, "(%d) cumul_size 0x%x\n", index, cumul_size);
 		if (cumul_size == last_cumul_size)
 			continue;	/* not populated */

 		csrow->first_page = last_cumul_size;
 		csrow->last_page = cumul_size - 1;
 		nr_pages = cumul_size - last_cumul_size;
 		last_cumul_size = cumul_size;

 		for (j = 0; j < nr_chans; j++) {
 			dimm = csrow->channels[j]->dimm;

 			dimm->nr_pages = nr_pages / nr_chans;
 			dimm->grain = 1 << 12;	/* I82875P_EAP has 4KiB reolution */
 			dimm->mtype = MEM_DDR;
 			dimm->dtype = DEV_UNKNOWN;
 			dimm->edac_mode = drc_ddim ? EDAC_SECDED : EDAC_NONE;
 		}
 	}
 }

 static int i82875p_probe1(struct pci_dev *pdev, int dev_idx)
 {
 	int rc = -ENODEV;
 	struct mem_ctl_info *mci;
 	struct edac_mc_layer layers[2];
 	struct i82875p_pvt *pvt;
 	struct pci_dev *ovrfl_pdev;
 	void __iomem *ovrfl_window;
 	u32 drc;
 	u32 nr_chans;
 	struct i82875p_error_info discard;

 	edac_dbg(0, "\n");

 	if (i82875p_setup_overfl_dev(pdev, &ovrfl_pdev, &ovrfl_window))
 		return -ENODEV;
 	drc = readl(ovrfl_window + I82875P_DRC);
 	nr_chans = dual_channel_active(drc) + 1;

 	layers[0].type = EDAC_MC_LAYER_CHIP_SELECT;
 	layers[0].size = I82875P_NR_CSROWS(nr_chans);
 	layers[0].is_virt_csrow = true;
 	layers[1].type = EDAC_MC_LAYER_CHANNEL;
 	layers[1].size = nr_chans;
 	layers[1].is_virt_csrow = false;
 	mci = edac_mc_alloc(0, ARRAY_SIZE(layers), layers, sizeof(*pvt));
 	if (!mci) {
 		rc = -ENOMEM;
 		goto fail0;
 	}

 	edac_dbg(3, "init mci\n");
 	mci->pdev = &pdev->dev;
 	mci->mtype_cap = MEM_FLAG_DDR;
 	mci->edac_ctl_cap = EDAC_FLAG_NONE | EDAC_FLAG_SECDED;
 	mci->edac_cap = EDAC_FLAG_UNKNOWN;
 	mci->mod_name = EDAC_MOD_STR;
 	mci->mod_ver = I82875P_REVISION;
 	mci->ctl_name = i82875p_devs[dev_idx].ctl_name;
 	mci->dev_name = pci_name(pdev);
 	mci->edac_check = i82875p_check;
 	mci->ctl_page_to_phys = NULL;
 	edac_dbg(3, "init pvt\n");
 	pvt = (struct i82875p_pvt *)mci->pvt_info;
 	pvt->ovrfl_pdev = ovrfl_pdev;
 	pvt->ovrfl_window = ovrfl_window;
 	i82875p_init_csrows(mci, pdev, ovrfl_window, drc);
 	i82875p_get_error_info(mci, &discard);	/* clear counters */

 	/* Here we assume that we will never see multiple instances of this
 	 * type of memory controller.  The ID is therefore hardcoded to 0.
 	 */
 	if (edac_mc_add_mc(mci)) {
 		edac_dbg(3, "failed edac_mc_add_mc()\n");
 		goto fail1;
 	}

 	/* allocating generic PCI control info */
 	i82875p_pci = edac_pci_create_generic_ctl(&pdev->dev, EDAC_MOD_STR);
 	if (!i82875p_pci) {
 		printk(KERN_WARNING
 			"%s(): Unable to create PCI control\n",
 			__func__);
 		printk(KERN_WARNING
 			"%s(): PCI error report via EDAC not setup\n",
 			__func__);
 	}

 	/* get this far and it's successful */
 	edac_dbg(3, "success\n");
 	return 0;

 fail1:
 	edac_mc_free(mci);

 fail0:
 	iounmap(ovrfl_window);
 	pci_release_regions(ovrfl_pdev);

 	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 i82875p_init_one(struct pci_dev *pdev,
 			    const struct pci_device_id *ent)
 {
 	int rc;

 	edac_dbg(0, "\n");
 	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 i82875p_remove_one(struct pci_dev *pdev)
 {
 	struct mem_ctl_info *mci;
 	struct i82875p_pvt *pvt = NULL;

 	edac_dbg(0, "\n");

 	if (i82875p_pci)
 		edac_pci_release_generic_ctl(i82875p_pci);

 	if ((mci = edac_mc_del_mc(&pdev->dev)) == 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);
 	}

 	edac_mc_free(mci);
 }

 static const struct pci_device_id i82875p_pci_tbl[] = {
 	{
 	 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 = i82875p_remove_one,
 	.id_table = i82875p_pci_tbl,
 };

 static int __init i82875p_init(void)
 {
 	int pci_rc;

 	edac_dbg(3, "\n");

        /* Ensure that the OPSTATE is set correctly for POLL or NMI */
        opstate_init();

 	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) {
 			edac_dbg(0, "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) {
 			edac_dbg(0, "875p init fail\n");
 			pci_rc = -ENODEV;
 			goto fail1;
 		}
 	}

 	return 0;

 fail1:
 	pci_unregister_driver(&i82875p_driver);

 fail0:
 	pci_dev_put(mci_pdev);
 	return pci_rc;
 }

 static void __exit i82875p_exit(void)
 {
 	edac_dbg(3, "\n");

 	i82875p_remove_one(mci_pdev);
 	pci_dev_put(mci_pdev);

 	pci_unregister_driver(&i82875p_driver);

 }

 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");

 module_param(edac_op_state, int, 0444);
 MODULE_PARM_DESC(edac_op_state, "EDAC Error Reporting state: 0=Poll,1=NMI");
	/*
	* 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/module.h>
	#include <linux/init.h>
	#include <linux/pci.h>
	#include <linux/pci_ids.h>
	#include <linux/edac.h>
	#include "edac_module.h"

	#define I82875P_REVISION " Ver: 2.0.2"
	#define EDAC_MOD_STR "i82875p_edac"

	#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_DIMMS 8
	#define I82875P_NR_CSROWS(nr_chans) (I82875P_NR_DIMMS / (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; / init dev: in case that AGP code has
	* already registered driver
	*/

	static struct edac_pci_ctl_info *i82875p_pci;

	static void i82875p_get_error_info(struct mem_ctl_info *mci,
	struct i82875p_error_info *info)
	{
	struct pci_dev *pdev;

	pdev = to_pci_dev(mci->pdev);

	/*
	* 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(pdev, I82875P_ERRSTS, &info->errsts);

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

	pci_read_config_dword(pdev, I82875P_EAP, &info->eap);
	pci_read_config_byte(pdev, I82875P_DES, &info->des);
	pci_read_config_byte(pdev, I82875P_DERRSYN, &info->derrsyn);
	pci_read_config_word(pdev, I82875P_ERRSTS, &info->errsts2);

	/*
	* 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->errsts ^ info->errsts2) & 0x0081) {
	pci_read_config_dword(pdev, I82875P_EAP, &info->eap);
	pci_read_config_byte(pdev, I82875P_DES, &info->des);
	pci_read_config_byte(pdev, I82875P_DERRSYN, &info->derrsyn);
	}

	pci_write_bits16(pdev, I82875P_ERRSTS, 0x0081, 0x0081);
	}

	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->errsts & 0x0081))
	return 0;

	if (!handle_errors)
	return 1;

	if ((info->errsts ^ info->errsts2) & 0x0081) {
	edac_mc_handle_error(HW_EVENT_ERR_UNCORRECTED, mci, 1, 0, 0, 0,
	-1, -1, -1,
	"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_error(HW_EVENT_ERR_UNCORRECTED, mci, 1,
	info->eap, 0, 0,
	row, -1, -1,
	"i82875p UE", "");
	else
	edac_mc_handle_error(HW_EVENT_ERR_CORRECTED, mci, 1,
	info->eap, 0, info->derrsyn,
	row, multi_chan ? (info->des & 0x1) : 0,
	-1, "i82875p CE", "");

	return 1;
	}

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

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

	/* Return 0 on success or 1 on failure. */
	static int i82875p_setup_overfl_dev(struct pci_dev *pdev,
	struct pci_dev **ovrfl_pdev,
	void __iomem **ovrfl_window)
	{
	struct pci_dev *dev;
	void __iomem *window;

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

	if (dev == NULL) {
	/* 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);
	dev = pci_scan_single_device(pdev->bus, PCI_DEVFN(6, 0));

	if (dev == NULL)
	return 1;

	pci_bus_assign_resources(dev->bus);
	pci_bus_add_device(dev);
	}

	*ovrfl_pdev = dev;

	if (pci_enable_device(dev)) {
	i82875p_printk(KERN_ERR, "%s(): Failed to enable overflow "
	"device\n", __func__);
	return 1;
	}

	if (pci_request_regions(dev, pci_name(dev))) {
	#ifdef CORRECT_BIOS
	goto fail0;
	#endif
	}

	/* cache is irrelevant for PCI bus reads/writes */
	window = pci_ioremap_bar(dev, 0);
	if (window == NULL) {
	i82875p_printk(KERN_ERR, "%s(): Failed to ioremap bar6\n",
	__func__);
	goto fail1;
	}

	*ovrfl_window = window;
	return 0;

	fail1:
	pci_release_regions(dev);

	#ifdef CORRECT_BIOS
	fail0:
	pci_disable_device(dev);
	#endif
	/* NOTE: the ovrfl proc entry and pci_dev are intentionally left */
	return 1;
	}

	/* Return 1 if dual channel mode is active. Else return 0. */
	static inline int dual_channel_active(u32 drc)
	{
	return (drc >> 21) & 0x1;
	}

	static void i82875p_init_csrows(struct mem_ctl_info *mci,
	struct pci_dev *pdev,
	void __iomem * ovrfl_window, u32 drc)
	{
	struct csrow_info *csrow;
	struct dimm_info *dimm;
	unsigned nr_chans = dual_channel_active(drc) + 1;
	unsigned long last_cumul_size;
	u8 value;
	u32 drc_ddim; /* DRAM Data Integrity Mode 0=none,2=edac */
	u32 cumul_size, nr_pages;
	int index, j;

	drc_ddim = (drc >> 18) & 0x1;
	last_cumul_size = 0;

	/* 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 (index = 0; index < mci->nr_csrows; index++) {
	csrow = mci->csrows[index];

	value = readb(ovrfl_window + I82875P_DRB + index);
	cumul_size = value << (I82875P_DRB_SHIFT - PAGE_SHIFT);
	edac_dbg(3, "(%d) cumul_size 0x%x\n", index, cumul_size);
	if (cumul_size == last_cumul_size)
	continue; /* not populated */

	csrow->first_page = last_cumul_size;
	csrow->last_page = cumul_size - 1;
	nr_pages = cumul_size - last_cumul_size;
	last_cumul_size = cumul_size;

	for (j = 0; j < nr_chans; j++) {
	dimm = csrow->channels[j]->dimm;

	dimm->nr_pages = nr_pages / nr_chans;
	dimm->grain = 1 << 12; /* I82875P_EAP has 4KiB reolution */
	dimm->mtype = MEM_DDR;
	dimm->dtype = DEV_UNKNOWN;
	dimm->edac_mode = drc_ddim ? EDAC_SECDED : EDAC_NONE;
	}
	}
	}

	static int i82875p_probe1(struct pci_dev *pdev, int dev_idx)
	{
	int rc = -ENODEV;
	struct mem_ctl_info *mci;
	struct edac_mc_layer layers[2];
	struct i82875p_pvt *pvt;
	struct pci_dev *ovrfl_pdev;
	void __iomem *ovrfl_window;
	u32 drc;
	u32 nr_chans;
	struct i82875p_error_info discard;

	edac_dbg(0, "\n");

	if (i82875p_setup_overfl_dev(pdev, &ovrfl_pdev, &ovrfl_window))
	return -ENODEV;
	drc = readl(ovrfl_window + I82875P_DRC);
	nr_chans = dual_channel_active(drc) + 1;

	layers[0].type = EDAC_MC_LAYER_CHIP_SELECT;
	layers[0].size = I82875P_NR_CSROWS(nr_chans);
	layers[0].is_virt_csrow = true;
	layers[1].type = EDAC_MC_LAYER_CHANNEL;
	layers[1].size = nr_chans;
	layers[1].is_virt_csrow = false;
	mci = edac_mc_alloc(0, ARRAY_SIZE(layers), layers, sizeof(*pvt));
	if (!mci) {
	rc = -ENOMEM;
	goto fail0;
	}

	edac_dbg(3, "init mci\n");
	mci->pdev = &pdev->dev;
	mci->mtype_cap = MEM_FLAG_DDR;
	mci->edac_ctl_cap = EDAC_FLAG_NONE \| EDAC_FLAG_SECDED;
	mci->edac_cap = EDAC_FLAG_UNKNOWN;
	mci->mod_name = EDAC_MOD_STR;
	mci->mod_ver = I82875P_REVISION;
	mci->ctl_name = i82875p_devs[dev_idx].ctl_name;
	mci->dev_name = pci_name(pdev);
	mci->edac_check = i82875p_check;
	mci->ctl_page_to_phys = NULL;
	edac_dbg(3, "init pvt\n");
	pvt = (struct i82875p_pvt *)mci->pvt_info;
	pvt->ovrfl_pdev = ovrfl_pdev;
	pvt->ovrfl_window = ovrfl_window;
	i82875p_init_csrows(mci, pdev, ovrfl_window, drc);
	i82875p_get_error_info(mci, &discard); /* clear counters */

	/* Here we assume that we will never see multiple instances of this
	* type of memory controller. The ID is therefore hardcoded to 0.
	*/
	if (edac_mc_add_mc(mci)) {
	edac_dbg(3, "failed edac_mc_add_mc()\n");
	goto fail1;
	}

	/* allocating generic PCI control info */
	i82875p_pci = edac_pci_create_generic_ctl(&pdev->dev, EDAC_MOD_STR);
	if (!i82875p_pci) {
	printk(KERN_WARNING
	"%s(): Unable to create PCI control\n",
	__func__);
	printk(KERN_WARNING
	"%s(): PCI error report via EDAC not setup\n",
	__func__);
	}

	/* get this far and it's successful */
	edac_dbg(3, "success\n");
	return 0;

	fail1:
	edac_mc_free(mci);

	fail0:
	iounmap(ovrfl_window);
	pci_release_regions(ovrfl_pdev);

	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 i82875p_init_one(struct pci_dev *pdev,
	const struct pci_device_id *ent)
	{
	int rc;

	edac_dbg(0, "\n");
	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 i82875p_remove_one(struct pci_dev *pdev)
	{
	struct mem_ctl_info *mci;
	struct i82875p_pvt *pvt = NULL;

	edac_dbg(0, "\n");

	if (i82875p_pci)
	edac_pci_release_generic_ctl(i82875p_pci);

	if ((mci = edac_mc_del_mc(&pdev->dev)) == 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);
	}

	edac_mc_free(mci);
	}

	static const struct pci_device_id i82875p_pci_tbl[] = {
	{
	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 = i82875p_remove_one,
	.id_table = i82875p_pci_tbl,
	};

	static int __init i82875p_init(void)
	{
	int pci_rc;

	edac_dbg(3, "\n");

	/* Ensure that the OPSTATE is set correctly for POLL or NMI */
	opstate_init();

	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) {
	edac_dbg(0, "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) {
	edac_dbg(0, "875p init fail\n");
	pci_rc = -ENODEV;
	goto fail1;
	}
	}

	return 0;

	fail1:
	pci_unregister_driver(&i82875p_driver);

	fail0:
	pci_dev_put(mci_pdev);
	return pci_rc;
	}

	static void __exit i82875p_exit(void)
	{
	edac_dbg(3, "\n");

	i82875p_remove_one(mci_pdev);
	pci_dev_put(mci_pdev);

	pci_unregister_driver(&i82875p_driver);

	}

	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");

	module_param(edac_op_state, int, 0444);
	MODULE_PARM_DESC(edac_op_state, "EDAC Error Reporting state: 0=Poll,1=NMI");