/*
   * 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 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
  ", 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
  ", __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
  ",

  			__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
  ", 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, "
  ");

  	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
  ");

  	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->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
  ");

  	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()
  ");

  		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
  ",
  			__func__);
  		printk(KERN_WARNING
  			"%s(): PCI error report via EDAC not setup
  ",
  			__func__);
  	}

  	/* get this far and it's successful */

  	edac_dbg(3, "success
  ");

  	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, "
  ");

  	i82875p_printk(KERN_INFO, "i82875p init one
  ");

  
  	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, "
  ");

  	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, "
  ");

  
         /* 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
  ");

  			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
  ");

  			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, "
  ");

  	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");