/*
 * 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");
                n_channels = 1;
        } else {
                edac_dbg(0, "In dual channel mode\n");
                n_channels = 2;
        }

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

        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;

        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)\n",
                        (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\n",
                        (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\n", 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:\n");

        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;

        rc = -ENOMEM;
        mci = edac_mc_alloc(0, ARRAY_SIZE(layers), layers, sizeof(struct i3200_priv));
        if (!mci)
                goto unmap;

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

        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\n", 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()\n");
                goto fail;
        }

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

fail:
        edac_mc_free(mci);
unmap:
        iounmap(window);

        return rc;
}

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

        edac_dbg(0, "MC:\n");

        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, "\n");

        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:\n");

        /* 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\n");
                        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\n");
                        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:\n");

        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");