/*
   * Intel 3200/3210 Memory Controller kernel module
   * Copyright (C) 2008-2009 Akamai Technologies, Inc.
   * Portions by Hitoshi Mitake <h.mitake@gmail.com>.
   *
   * This file may be distributed under the terms of the
   * GNU General Public License.
   */
  
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/pci.h>
  #include <linux/pci_ids.h>

  #include <linux/edac.h>
  #include <linux/io.h>

  #include "edac_module.h"

  #include <linux/io-64-nonatomic-lo-hi.h>

  #define EDAC_MOD_STR        "i3200_edac"
  
  #define PCI_DEVICE_ID_INTEL_3200_HB    0x29f0

  #define I3200_DIMMS		4

  #define I3200_RANKS		8
  #define I3200_RANKS_PER_CHANNEL	4
  #define I3200_CHANNELS		2
  
  /* Intel 3200 register addresses - device 0 function 0 - DRAM Controller */
  
  #define I3200_MCHBAR_LOW	0x48	/* MCH Memory Mapped Register BAR */
  #define I3200_MCHBAR_HIGH	0x4c
  #define I3200_MCHBAR_MASK	0xfffffc000ULL	/* bits 35:14 */
  #define I3200_MMR_WINDOW_SIZE	16384
  
  #define I3200_TOM		0xa0	/* Top of Memory (16b)
  		 *
  		 * 15:10 reserved
  		 *  9:0  total populated physical memory
  		 */
  #define I3200_TOM_MASK		0x3ff	/* bits 9:0 */
  #define I3200_TOM_SHIFT		26	/* 64MiB grain */
  
  #define I3200_ERRSTS		0xc8	/* Error Status Register (16b)
  		 *
  		 * 15    reserved
  		 * 14    Isochronous TBWRR Run Behind FIFO Full
  		 *       (ITCV)
  		 * 13    Isochronous TBWRR Run Behind FIFO Put
  		 *       (ITSTV)
  		 * 12    reserved
  		 * 11    MCH Thermal Sensor Event
  		 *       for SMI/SCI/SERR (GTSE)
  		 * 10    reserved
  		 *  9    LOCK to non-DRAM Memory Flag (LCKF)
  		 *  8    reserved
  		 *  7    DRAM Throttle Flag (DTF)
  		 *  6:2  reserved
  		 *  1    Multi-bit DRAM ECC Error Flag (DMERR)
  		 *  0    Single-bit DRAM ECC Error Flag (DSERR)
  		 */
  #define I3200_ERRSTS_UE		0x0002
  #define I3200_ERRSTS_CE		0x0001
  #define I3200_ERRSTS_BITS	(I3200_ERRSTS_UE | I3200_ERRSTS_CE)
  
  
  /* Intel  MMIO register space - device 0 function 0 - MMR space */
  
  #define I3200_C0DRB	0x200	/* Channel 0 DRAM Rank Boundary (16b x 4)
  		 *
  		 * 15:10 reserved
  		 *  9:0  Channel 0 DRAM Rank Boundary Address
  		 */
  #define I3200_C1DRB	0x600	/* Channel 1 DRAM Rank Boundary (16b x 4) */
  #define I3200_DRB_MASK	0x3ff	/* bits 9:0 */
  #define I3200_DRB_SHIFT	26	/* 64MiB grain */
  
  #define I3200_C0ECCERRLOG	0x280	/* Channel 0 ECC Error Log (64b)
  		 *
  		 * 63:48 Error Column Address (ERRCOL)
  		 * 47:32 Error Row Address (ERRROW)
  		 * 31:29 Error Bank Address (ERRBANK)
  		 * 28:27 Error Rank Address (ERRRANK)
  		 * 26:24 reserved
  		 * 23:16 Error Syndrome (ERRSYND)
  		 * 15: 2 reserved
  		 *    1  Multiple Bit Error Status (MERRSTS)
  		 *    0  Correctable Error Status (CERRSTS)
  		 */
  #define I3200_C1ECCERRLOG		0x680	/* Chan 1 ECC Error Log (64b) */
  #define I3200_ECCERRLOG_CE		0x1
  #define I3200_ECCERRLOG_UE		0x2
  #define I3200_ECCERRLOG_RANK_BITS	0x18000000
  #define I3200_ECCERRLOG_RANK_SHIFT	27
  #define I3200_ECCERRLOG_SYNDROME_BITS	0xff0000
  #define I3200_ECCERRLOG_SYNDROME_SHIFT	16
  #define I3200_CAPID0			0xe0	/* P.95 of spec for details */
  
  struct i3200_priv {
  	void __iomem *window;
  };
  
  static int nr_channels;
  
  static int how_many_channels(struct pci_dev *pdev)
  {

  	int n_channels;

  	unsigned char capid0_8b; /* 8th byte of CAPID0 */
  
  	pci_read_config_byte(pdev, I3200_CAPID0 + 8, &capid0_8b);

  	if (capid0_8b & 0x20) { /* check DCD: Dual Channel Disable */

  		edac_dbg(0, "In single channel mode
  ");

  		n_channels = 1;

  	} else {

  		edac_dbg(0, "In dual channel mode
  ");

  		n_channels = 2;

  	}

  
  	if (capid0_8b & 0x10) /* check if both channels are filled */
  		edac_dbg(0, "2 DIMMS per channel disabled
  ");
  	else
  		edac_dbg(0, "2 DIMMS per channel enabled
  ");
  
  	return n_channels;

  }
  
  static unsigned long eccerrlog_syndrome(u64 log)
  {
  	return (log & I3200_ECCERRLOG_SYNDROME_BITS) >>
  		I3200_ECCERRLOG_SYNDROME_SHIFT;
  }
  
  static int eccerrlog_row(int channel, u64 log)
  {
  	u64 rank = ((log & I3200_ECCERRLOG_RANK_BITS) >>
  		I3200_ECCERRLOG_RANK_SHIFT);
  	return rank | (channel * I3200_RANKS_PER_CHANNEL);
  }
  
  enum i3200_chips {
  	I3200 = 0,
  };
  
  struct i3200_dev_info {
  	const char *ctl_name;
  };
  
  struct i3200_error_info {
  	u16 errsts;
  	u16 errsts2;
  	u64 eccerrlog[I3200_CHANNELS];
  };
  
  static const struct i3200_dev_info i3200_devs[] = {
  	[I3200] = {
  		.ctl_name = "i3200"
  	},
  };
  
  static struct pci_dev *mci_pdev;
  static int i3200_registered = 1;
  
  
  static void i3200_clear_error_info(struct mem_ctl_info *mci)
  {
  	struct pci_dev *pdev;

  	pdev = to_pci_dev(mci->pdev);

  
  	/*
  	 * Clear any error bits.
  	 * (Yes, we really clear bits by writing 1 to them.)
  	 */
  	pci_write_bits16(pdev, I3200_ERRSTS, I3200_ERRSTS_BITS,
  		I3200_ERRSTS_BITS);
  }
  
  static void i3200_get_and_clear_error_info(struct mem_ctl_info *mci,
  		struct i3200_error_info *info)
  {
  	struct pci_dev *pdev;
  	struct i3200_priv *priv = mci->pvt_info;
  	void __iomem *window = priv->window;

  	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, I3200_ERRSTS, &info->errsts);
  	if (!(info->errsts & I3200_ERRSTS_BITS))
  		return;
  
  	info->eccerrlog[0] = readq(window + I3200_C0ECCERRLOG);
  	if (nr_channels == 2)
  		info->eccerrlog[1] = readq(window + I3200_C1ECCERRLOG);
  
  	pci_read_config_word(pdev, I3200_ERRSTS, &info->errsts2);
  
  	/*
  	 * If the error is the same for both reads then the first set
  	 * of reads is valid.  If there is a change then there is a CE
  	 * with no info and the second set of reads is valid and
  	 * should be UE info.
  	 */
  	if ((info->errsts ^ info->errsts2) & I3200_ERRSTS_BITS) {
  		info->eccerrlog[0] = readq(window + I3200_C0ECCERRLOG);
  		if (nr_channels == 2)
  			info->eccerrlog[1] = readq(window + I3200_C1ECCERRLOG);
  	}
  
  	i3200_clear_error_info(mci);
  }
  
  static void i3200_process_error_info(struct mem_ctl_info *mci,
  		struct i3200_error_info *info)
  {
  	int channel;
  	u64 log;
  
  	if (!(info->errsts & I3200_ERRSTS_BITS))
  		return;
  
  	if ((info->errsts ^ info->errsts2) & I3200_ERRSTS_BITS) {

  		edac_mc_handle_error(HW_EVENT_ERR_UNCORRECTED, mci, 1, 0, 0, 0,

  				     -1, -1, -1, "UE overwrote CE", "");

  		info->errsts = info->errsts2;
  	}
  
  	for (channel = 0; channel < nr_channels; channel++) {
  		log = info->eccerrlog[channel];
  		if (log & I3200_ECCERRLOG_UE) {

  			edac_mc_handle_error(HW_EVENT_ERR_UNCORRECTED, mci, 1,

  					     0, 0, 0,
  					     eccerrlog_row(channel, log),
  					     -1, -1,

  					     "i3000 UE", "");

  		} else if (log & I3200_ECCERRLOG_CE) {

  			edac_mc_handle_error(HW_EVENT_ERR_CORRECTED, mci, 1,

  					     0, 0, eccerrlog_syndrome(log),
  					     eccerrlog_row(channel, log),
  					     -1, -1,

  					     "i3000 CE", "");

  		}
  	}
  }
  
  static void i3200_check(struct mem_ctl_info *mci)
  {
  	struct i3200_error_info info;

  	edac_dbg(1, "MC%d
  ", mci->mc_idx);

  	i3200_get_and_clear_error_info(mci, &info);
  	i3200_process_error_info(mci, &info);
  }

  static void __iomem *i3200_map_mchbar(struct pci_dev *pdev)

  {
  	union {
  		u64 mchbar;
  		struct {
  			u32 mchbar_low;
  			u32 mchbar_high;
  		};
  	} u;
  	void __iomem *window;
  
  	pci_read_config_dword(pdev, I3200_MCHBAR_LOW, &u.mchbar_low);
  	pci_read_config_dword(pdev, I3200_MCHBAR_HIGH, &u.mchbar_high);
  	u.mchbar &= I3200_MCHBAR_MASK;
  
  	if (u.mchbar != (resource_size_t)u.mchbar) {
  		printk(KERN_ERR
  			"i3200: mmio space beyond accessible range (0x%llx)
  ",
  			(unsigned long long)u.mchbar);
  		return NULL;
  	}

  	window = ioremap(u.mchbar, I3200_MMR_WINDOW_SIZE);

  	if (!window)
  		printk(KERN_ERR "i3200: cannot map mmio space at 0x%llx
  ",
  			(unsigned long long)u.mchbar);
  
  	return window;
  }
  
  
  static void i3200_get_drbs(void __iomem *window,
  	u16 drbs[I3200_CHANNELS][I3200_RANKS_PER_CHANNEL])
  {
  	int i;
  
  	for (i = 0; i < I3200_RANKS_PER_CHANNEL; i++) {
  		drbs[0][i] = readw(window + I3200_C0DRB + 2*i) & I3200_DRB_MASK;
  		drbs[1][i] = readw(window + I3200_C1DRB + 2*i) & I3200_DRB_MASK;

  
  		edac_dbg(0, "drb[0][%d] = %d, drb[1][%d] = %d
  ", i, drbs[0][i], i, drbs[1][i]);

  	}
  }
  
  static bool i3200_is_stacked(struct pci_dev *pdev,
  	u16 drbs[I3200_CHANNELS][I3200_RANKS_PER_CHANNEL])
  {
  	u16 tom;
  
  	pci_read_config_word(pdev, I3200_TOM, &tom);
  	tom &= I3200_TOM_MASK;
  
  	return drbs[I3200_CHANNELS - 1][I3200_RANKS_PER_CHANNEL - 1] == tom;
  }
  
  static unsigned long drb_to_nr_pages(
  	u16 drbs[I3200_CHANNELS][I3200_RANKS_PER_CHANNEL], bool stacked,
  	int channel, int rank)
  {
  	int n;
  
  	n = drbs[channel][rank];

  	if (!n)
  		return 0;

  	if (rank > 0)
  		n -= drbs[channel][rank - 1];
  	if (stacked && (channel == 1) &&
  	drbs[channel][rank] == drbs[channel][I3200_RANKS_PER_CHANNEL - 1])
  		n -= drbs[0][I3200_RANKS_PER_CHANNEL - 1];
  
  	n <<= (I3200_DRB_SHIFT - PAGE_SHIFT);
  	return n;
  }
  
  static int i3200_probe1(struct pci_dev *pdev, int dev_idx)
  {
  	int rc;

  	int i, j;

  	struct mem_ctl_info *mci = NULL;

  	struct edac_mc_layer layers[2];

  	u16 drbs[I3200_CHANNELS][I3200_RANKS_PER_CHANNEL];
  	bool stacked;
  	void __iomem *window;
  	struct i3200_priv *priv;

  	edac_dbg(0, "MC:
  ");

  
  	window = i3200_map_mchbar(pdev);
  	if (!window)
  		return -ENODEV;
  
  	i3200_get_drbs(window, drbs);
  	nr_channels = how_many_channels(pdev);

  	layers[0].type = EDAC_MC_LAYER_CHIP_SELECT;
  	layers[0].size = I3200_DIMMS;
  	layers[0].is_virt_csrow = true;
  	layers[1].type = EDAC_MC_LAYER_CHANNEL;
  	layers[1].size = nr_channels;
  	layers[1].is_virt_csrow = false;

  	mci = edac_mc_alloc(0, ARRAY_SIZE(layers), layers,

  			    sizeof(struct i3200_priv));

  	if (!mci)
  		return -ENOMEM;

  	edac_dbg(3, "MC: init mci
  ");

  	mci->pdev = &pdev->dev;

  	mci->mtype_cap = MEM_FLAG_DDR2;
  
  	mci->edac_ctl_cap = EDAC_FLAG_SECDED;
  	mci->edac_cap = EDAC_FLAG_SECDED;
  
  	mci->mod_name = EDAC_MOD_STR;

  	mci->ctl_name = i3200_devs[dev_idx].ctl_name;
  	mci->dev_name = pci_name(pdev);
  	mci->edac_check = i3200_check;
  	mci->ctl_page_to_phys = NULL;
  	priv = mci->pvt_info;
  	priv->window = window;
  
  	stacked = i3200_is_stacked(pdev, drbs);
  
  	/*
  	 * The dram rank boundary (DRB) reg values are boundary addresses
  	 * for each DRAM rank with a granularity of 64MB.  DRB regs are
  	 * cumulative; the last one will contain the total memory
  	 * contained in all ranks.
  	 */

  	for (i = 0; i < I3200_DIMMS; i++) {

  		unsigned long nr_pages;

  		for (j = 0; j < nr_channels; j++) {

  			struct dimm_info *dimm = edac_get_dimm(mci, i, j, 0);

  			nr_pages = drb_to_nr_pages(drbs, stacked, j, i);
  			if (nr_pages == 0)
  				continue;

  			edac_dbg(0, "csrow %d, channel %d%s, size = %ld MiB
  ", i, j,

  				 stacked ? " (stacked)" : "", PAGES_TO_MiB(nr_pages));

  			dimm->nr_pages = nr_pages;

  			dimm->grain = nr_pages << PAGE_SHIFT;
  			dimm->mtype = MEM_DDR2;
  			dimm->dtype = DEV_UNKNOWN;
  			dimm->edac_mode = EDAC_UNKNOWN;
  		}

  	}
  
  	i3200_clear_error_info(mci);
  
  	rc = -ENODEV;
  	if (edac_mc_add_mc(mci)) {

  		edac_dbg(3, "MC: failed edac_mc_add_mc()
  ");

  		goto fail;
  	}
  
  	/* get this far and it's successful */

  	edac_dbg(3, "MC: success
  ");

  	return 0;
  
  fail:
  	iounmap(window);
  	if (mci)
  		edac_mc_free(mci);
  
  	return rc;
  }

  static int i3200_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)

  {
  	int rc;

  	edac_dbg(0, "MC:
  ");

  
  	if (pci_enable_device(pdev) < 0)
  		return -EIO;
  
  	rc = i3200_probe1(pdev, ent->driver_data);
  	if (!mci_pdev)
  		mci_pdev = pci_dev_get(pdev);
  
  	return rc;
  }

  static void i3200_remove_one(struct pci_dev *pdev)

  {
  	struct mem_ctl_info *mci;
  	struct i3200_priv *priv;

  	edac_dbg(0, "
  ");

  
  	mci = edac_mc_del_mc(&pdev->dev);
  	if (!mci)
  		return;
  
  	priv = mci->pvt_info;
  	iounmap(priv->window);
  
  	edac_mc_free(mci);

  
  	pci_disable_device(pdev);

  }

  static const struct pci_device_id i3200_pci_tbl[] = {

  	{
  		PCI_VEND_DEV(INTEL, 3200_HB), PCI_ANY_ID, PCI_ANY_ID, 0, 0,
  		I3200},
  	{
  		0,
  	}            /* 0 terminated list. */
  };
  
  MODULE_DEVICE_TABLE(pci, i3200_pci_tbl);
  
  static struct pci_driver i3200_driver = {
  	.name = EDAC_MOD_STR,
  	.probe = i3200_init_one,

  	.remove = i3200_remove_one,

  	.id_table = i3200_pci_tbl,
  };
  
  static int __init i3200_init(void)
  {
  	int pci_rc;

  	edac_dbg(3, "MC:
  ");

  
  	/* Ensure that the OPSTATE is set correctly for POLL or NMI */
  	opstate_init();
  
  	pci_rc = pci_register_driver(&i3200_driver);
  	if (pci_rc < 0)
  		goto fail0;
  
  	if (!mci_pdev) {
  		i3200_registered = 0;
  		mci_pdev = pci_get_device(PCI_VENDOR_ID_INTEL,
  				PCI_DEVICE_ID_INTEL_3200_HB, NULL);
  		if (!mci_pdev) {

  			edac_dbg(0, "i3200 pci_get_device fail
  ");

  			pci_rc = -ENODEV;
  			goto fail1;
  		}
  
  		pci_rc = i3200_init_one(mci_pdev, i3200_pci_tbl);
  		if (pci_rc < 0) {

  			edac_dbg(0, "i3200 init fail
  ");

  			pci_rc = -ENODEV;
  			goto fail1;
  		}
  	}
  
  	return 0;
  
  fail1:
  	pci_unregister_driver(&i3200_driver);
  
  fail0:

  	pci_dev_put(mci_pdev);

  
  	return pci_rc;
  }
  
  static void __exit i3200_exit(void)
  {

  	edac_dbg(3, "MC:
  ");

  
  	pci_unregister_driver(&i3200_driver);
  	if (!i3200_registered) {
  		i3200_remove_one(mci_pdev);
  		pci_dev_put(mci_pdev);
  	}
  }
  
  module_init(i3200_init);
  module_exit(i3200_exit);
  
  MODULE_LICENSE("GPL");
  MODULE_AUTHOR("Akamai Technologies, Inc.");
  MODULE_DESCRIPTION("MC support for Intel 3200 memory hub controllers");
  
  module_param(edac_op_state, int, 0444);
  MODULE_PARM_DESC(edac_op_state, "EDAC Error Reporting state: 0=Poll,1=NMI");