/*
 * 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_core.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_add_device(dev);
                pci_bus_assign_resources(dev->bus);
        }

        *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");

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

        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:
        if (mci_pdev != NULL)
                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");