/*
 * cpc925_edac.c, EDAC driver for IBM CPC925 Bridge and Memory Controller.
 *
 * Copyright (c) 2008 Wind River Systems, Inc.
 *
 * Authors:     Cao Qingtao <qingtao.cao@windriver.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/edac.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/gfp.h>

#include "edac_core.h"
#include "edac_module.h"

#define CPC925_EDAC_REVISION    " Ver: 1.0.0"
#define CPC925_EDAC_MOD_STR     "cpc925_edac"

#define cpc925_printk(level, fmt, arg...) \
        edac_printk(level, "CPC925", fmt, ##arg)

#define cpc925_mc_printk(mci, level, fmt, arg...) \
        edac_mc_chipset_printk(mci, level, "CPC925", fmt, ##arg)

/*
 * CPC925 registers are of 32 bits with bit0 defined at the
 * most significant bit and bit31 at that of least significant.
 */
#define CPC925_BITS_PER_REG     32
#define CPC925_BIT(nr)          (1UL << (CPC925_BITS_PER_REG - 1 - nr))

/*
 * EDAC device names for the error detections of
 * CPU Interface and Hypertransport Link.
 */
#define CPC925_CPU_ERR_DEV      "cpu"
#define CPC925_HT_LINK_DEV      "htlink"

/* Suppose DDR Refresh cycle is 15.6 microsecond */
#define CPC925_REF_FREQ         0xFA69
#define CPC925_SCRUB_BLOCK_SIZE 64      /* bytes */
#define CPC925_NR_CSROWS        8

/*
 * All registers and bits definitions are taken from
 * "CPC925 Bridge and Memory Controller User Manual, SA14-2761-02".
 */

/*
 * CPU and Memory Controller Registers
 */
/************************************************************
 *      Processor Interface Exception Mask Register (APIMASK)
 ************************************************************/
#define REG_APIMASK_OFFSET      0x30070
enum apimask_bits {
        APIMASK_DART    = CPC925_BIT(0), /* DART Exception */
        APIMASK_ADI0    = CPC925_BIT(1), /* Handshake Error on PI0_ADI */
        APIMASK_ADI1    = CPC925_BIT(2), /* Handshake Error on PI1_ADI */
        APIMASK_STAT    = CPC925_BIT(3), /* Status Exception */
        APIMASK_DERR    = CPC925_BIT(4), /* Data Error Exception */
        APIMASK_ADRS0   = CPC925_BIT(5), /* Addressing Exception on PI0 */
        APIMASK_ADRS1   = CPC925_BIT(6), /* Addressing Exception on PI1 */
                                         /* BIT(7) Reserved */
        APIMASK_ECC_UE_H = CPC925_BIT(8), /* UECC upper */
        APIMASK_ECC_CE_H = CPC925_BIT(9), /* CECC upper */
        APIMASK_ECC_UE_L = CPC925_BIT(10), /* UECC lower */
        APIMASK_ECC_CE_L = CPC925_BIT(11), /* CECC lower */

        CPU_MASK_ENABLE = (APIMASK_DART | APIMASK_ADI0 | APIMASK_ADI1 |
                           APIMASK_STAT | APIMASK_DERR | APIMASK_ADRS0 |
                           APIMASK_ADRS1),
        ECC_MASK_ENABLE = (APIMASK_ECC_UE_H | APIMASK_ECC_CE_H |
                           APIMASK_ECC_UE_L | APIMASK_ECC_CE_L),
};

/************************************************************
 *      Processor Interface Exception Register (APIEXCP)
 ************************************************************/
#define REG_APIEXCP_OFFSET      0x30060
enum apiexcp_bits {
        APIEXCP_DART    = CPC925_BIT(0), /* DART Exception */
        APIEXCP_ADI0    = CPC925_BIT(1), /* Handshake Error on PI0_ADI */
        APIEXCP_ADI1    = CPC925_BIT(2), /* Handshake Error on PI1_ADI */
        APIEXCP_STAT    = CPC925_BIT(3), /* Status Exception */
        APIEXCP_DERR    = CPC925_BIT(4), /* Data Error Exception */
        APIEXCP_ADRS0   = CPC925_BIT(5), /* Addressing Exception on PI0 */
        APIEXCP_ADRS1   = CPC925_BIT(6), /* Addressing Exception on PI1 */
                                         /* BIT(7) Reserved */
        APIEXCP_ECC_UE_H = CPC925_BIT(8), /* UECC upper */
        APIEXCP_ECC_CE_H = CPC925_BIT(9), /* CECC upper */
        APIEXCP_ECC_UE_L = CPC925_BIT(10), /* UECC lower */
        APIEXCP_ECC_CE_L = CPC925_BIT(11), /* CECC lower */

        CPU_EXCP_DETECTED = (APIEXCP_DART | APIEXCP_ADI0 | APIEXCP_ADI1 |
                             APIEXCP_STAT | APIEXCP_DERR | APIEXCP_ADRS0 |
                             APIEXCP_ADRS1),
        UECC_EXCP_DETECTED = (APIEXCP_ECC_UE_H | APIEXCP_ECC_UE_L),
        CECC_EXCP_DETECTED = (APIEXCP_ECC_CE_H | APIEXCP_ECC_CE_L),
        ECC_EXCP_DETECTED = (UECC_EXCP_DETECTED | CECC_EXCP_DETECTED),
};

/************************************************************
 *      Memory Bus Configuration Register (MBCR)
************************************************************/
#define REG_MBCR_OFFSET         0x2190
#define MBCR_64BITCFG_SHIFT     23
#define MBCR_64BITCFG_MASK      (1UL << MBCR_64BITCFG_SHIFT)
#define MBCR_64BITBUS_SHIFT     22
#define MBCR_64BITBUS_MASK      (1UL << MBCR_64BITBUS_SHIFT)

/************************************************************
 *      Memory Bank Mode Register (MBMR)
************************************************************/
#define REG_MBMR_OFFSET         0x21C0
#define MBMR_MODE_MAX_VALUE     0xF
#define MBMR_MODE_SHIFT         25
#define MBMR_MODE_MASK          (MBMR_MODE_MAX_VALUE << MBMR_MODE_SHIFT)
#define MBMR_BBA_SHIFT          24
#define MBMR_BBA_MASK           (1UL << MBMR_BBA_SHIFT)

/************************************************************
 *      Memory Bank Boundary Address Register (MBBAR)
 ************************************************************/
#define REG_MBBAR_OFFSET        0x21D0
#define MBBAR_BBA_MAX_VALUE     0xFF
#define MBBAR_BBA_SHIFT         24
#define MBBAR_BBA_MASK          (MBBAR_BBA_MAX_VALUE << MBBAR_BBA_SHIFT)

/************************************************************
 *      Memory Scrub Control Register (MSCR)
 ************************************************************/
#define REG_MSCR_OFFSET         0x2400
#define MSCR_SCRUB_MOD_MASK     0xC0000000 /* scrub_mod - bit0:1*/
#define MSCR_BACKGR_SCRUB       0x40000000 /* 01 */
#define MSCR_SI_SHIFT           16      /* si - bit8:15*/
#define MSCR_SI_MAX_VALUE       0xFF
#define MSCR_SI_MASK            (MSCR_SI_MAX_VALUE << MSCR_SI_SHIFT)

/************************************************************
 *      Memory Scrub Range Start Register (MSRSR)
 ************************************************************/
#define REG_MSRSR_OFFSET        0x2410

/************************************************************
 *      Memory Scrub Range End Register (MSRER)
 ************************************************************/
#define REG_MSRER_OFFSET        0x2420

/************************************************************
 *      Memory Scrub Pattern Register (MSPR)
 ************************************************************/
#define REG_MSPR_OFFSET         0x2430

/************************************************************
 *      Memory Check Control Register (MCCR)
 ************************************************************/
#define REG_MCCR_OFFSET         0x2440
enum mccr_bits {
        MCCR_ECC_EN     = CPC925_BIT(0), /* ECC high and low check */
};

/************************************************************
 *      Memory Check Range End Register (MCRER)
 ************************************************************/
#define REG_MCRER_OFFSET        0x2450

/************************************************************
 *      Memory Error Address Register (MEAR)
 ************************************************************/
#define REG_MEAR_OFFSET         0x2460
#define MEAR_BCNT_MAX_VALUE     0x3
#define MEAR_BCNT_SHIFT         30
#define MEAR_BCNT_MASK          (MEAR_BCNT_MAX_VALUE << MEAR_BCNT_SHIFT)
#define MEAR_RANK_MAX_VALUE     0x7
#define MEAR_RANK_SHIFT         27
#define MEAR_RANK_MASK          (MEAR_RANK_MAX_VALUE << MEAR_RANK_SHIFT)
#define MEAR_COL_MAX_VALUE      0x7FF
#define MEAR_COL_SHIFT          16
#define MEAR_COL_MASK           (MEAR_COL_MAX_VALUE << MEAR_COL_SHIFT)
#define MEAR_BANK_MAX_VALUE     0x3
#define MEAR_BANK_SHIFT         14
#define MEAR_BANK_MASK          (MEAR_BANK_MAX_VALUE << MEAR_BANK_SHIFT)
#define MEAR_ROW_MASK           0x00003FFF

/************************************************************
 *      Memory Error Syndrome Register (MESR)
 ************************************************************/
#define REG_MESR_OFFSET         0x2470
#define MESR_ECC_SYN_H_MASK     0xFF00
#define MESR_ECC_SYN_L_MASK     0x00FF

/************************************************************
 *      Memory Mode Control Register (MMCR)
 ************************************************************/
#define REG_MMCR_OFFSET         0x2500
enum mmcr_bits {
        MMCR_REG_DIMM_MODE = CPC925_BIT(3),
};

/*
 * HyperTransport Link Registers
 */
/************************************************************
 *  Error Handling/Enumeration Scratch Pad Register (ERRCTRL)
 ************************************************************/
#define REG_ERRCTRL_OFFSET      0x70140
enum errctrl_bits {                      /* nonfatal interrupts for */
        ERRCTRL_SERR_NF = CPC925_BIT(0), /* system error */
        ERRCTRL_CRC_NF  = CPC925_BIT(1), /* CRC error */
        ERRCTRL_RSP_NF  = CPC925_BIT(2), /* Response error */
        ERRCTRL_EOC_NF  = CPC925_BIT(3), /* End-Of-Chain error */
        ERRCTRL_OVF_NF  = CPC925_BIT(4), /* Overflow error */
        ERRCTRL_PROT_NF = CPC925_BIT(5), /* Protocol error */

        ERRCTRL_RSP_ERR = CPC925_BIT(6), /* Response error received */
        ERRCTRL_CHN_FAL = CPC925_BIT(7), /* Sync flooding detected */

        HT_ERRCTRL_ENABLE = (ERRCTRL_SERR_NF | ERRCTRL_CRC_NF |
                             ERRCTRL_RSP_NF | ERRCTRL_EOC_NF |
                             ERRCTRL_OVF_NF | ERRCTRL_PROT_NF),
        HT_ERRCTRL_DETECTED = (ERRCTRL_RSP_ERR | ERRCTRL_CHN_FAL),
};

/************************************************************
 *  Link Configuration and Link Control Register (LINKCTRL)
 ************************************************************/
#define REG_LINKCTRL_OFFSET     0x70110
enum linkctrl_bits {
        LINKCTRL_CRC_ERR        = (CPC925_BIT(22) | CPC925_BIT(23)),
        LINKCTRL_LINK_FAIL      = CPC925_BIT(27),

        HT_LINKCTRL_DETECTED    = (LINKCTRL_CRC_ERR | LINKCTRL_LINK_FAIL),
};

/************************************************************
 *  Link FreqCap/Error/Freq/Revision ID Register (LINKERR)
 ************************************************************/
#define REG_LINKERR_OFFSET      0x70120
enum linkerr_bits {
        LINKERR_EOC_ERR         = CPC925_BIT(17), /* End-Of-Chain error */
        LINKERR_OVF_ERR         = CPC925_BIT(18), /* Receive Buffer Overflow */
        LINKERR_PROT_ERR        = CPC925_BIT(19), /* Protocol error */

        HT_LINKERR_DETECTED     = (LINKERR_EOC_ERR | LINKERR_OVF_ERR |
                                   LINKERR_PROT_ERR),
};

/************************************************************
 *      Bridge Control Register (BRGCTRL)
 ************************************************************/
#define REG_BRGCTRL_OFFSET      0x70300
enum brgctrl_bits {
        BRGCTRL_DETSERR = CPC925_BIT(0), /* SERR on Secondary Bus */
        BRGCTRL_SECBUSRESET = CPC925_BIT(9), /* Secondary Bus Reset */
};

/* Private structure for edac memory controller */
struct cpc925_mc_pdata {
        void __iomem *vbase;
        unsigned long total_mem;
        const char *name;
        int edac_idx;
};

/* Private structure for common edac device */
struct cpc925_dev_info {
        void __iomem *vbase;
        struct platform_device *pdev;
        char *ctl_name;
        int edac_idx;
        struct edac_device_ctl_info *edac_dev;
        void (*init)(struct cpc925_dev_info *dev_info);
        void (*exit)(struct cpc925_dev_info *dev_info);
        void (*check)(struct edac_device_ctl_info *edac_dev);
};

/* Get total memory size from Open Firmware DTB */
static void get_total_mem(struct cpc925_mc_pdata *pdata)
{
        struct device_node *np = NULL;
        const unsigned int *reg, *reg_end;
        int len, sw, aw;
        unsigned long start, size;

        np = of_find_node_by_type(NULL, "memory");
        if (!np)
                return;

        aw = of_n_addr_cells(np);
        sw = of_n_size_cells(np);
        reg = (const unsigned int *)of_get_property(np, "reg", &len);
        reg_end = reg + len/4;

        pdata->total_mem = 0;
        do {
                start = of_read_number(reg, aw);
                reg += aw;
                size = of_read_number(reg, sw);
                reg += sw;
                debugf1("%s: start 0x%lx, size 0x%lx\n", __func__,
                        start, size);
                pdata->total_mem += size;
        } while (reg < reg_end);

        of_node_put(np);
        debugf0("%s: total_mem 0x%lx\n", __func__, pdata->total_mem);
}

static void cpc925_init_csrows(struct mem_ctl_info *mci)
{
        struct cpc925_mc_pdata *pdata = mci->pvt_info;
        struct csrow_info *csrow;
        int index;
        u32 mbmr, mbbar, bba;
        unsigned long row_size, last_nr_pages = 0;

        get_total_mem(pdata);

        for (index = 0; index < mci->nr_csrows; index++) {
                mbmr = __raw_readl(pdata->vbase + REG_MBMR_OFFSET +
                                   0x20 * index);
                mbbar = __raw_readl(pdata->vbase + REG_MBBAR_OFFSET +
                                   0x20 + index);
                bba = (((mbmr & MBMR_BBA_MASK) >> MBMR_BBA_SHIFT) << 8) |
                       ((mbbar & MBBAR_BBA_MASK) >> MBBAR_BBA_SHIFT);

                if (bba == 0)
                        continue; /* not populated */

                csrow = &mci->csrows[index];

                row_size = bba * (1UL << 28);   /* 256M */
                csrow->first_page = last_nr_pages;
                csrow->nr_pages = row_size >> PAGE_SHIFT;
                csrow->last_page = csrow->first_page + csrow->nr_pages - 1;
                last_nr_pages = csrow->last_page + 1;

                csrow->mtype = MEM_RDDR;
                csrow->edac_mode = EDAC_SECDED;

                switch (csrow->nr_channels) {
                case 1: /* Single channel */
                        csrow->grain = 32; /* four-beat burst of 32 bytes */
                        break;
                case 2: /* Dual channel */
                default:
                        csrow->grain = 64; /* four-beat burst of 64 bytes */
                        break;
                }

                switch ((mbmr & MBMR_MODE_MASK) >> MBMR_MODE_SHIFT) {
                case 6: /* 0110, no way to differentiate X8 VS X16 */
                case 5: /* 0101 */
                case 8: /* 1000 */
                        csrow->dtype = DEV_X16;
                        break;
                case 7: /* 0111 */
                case 9: /* 1001 */
                        csrow->dtype = DEV_X8;
                        break;
                default:
                        csrow->dtype = DEV_UNKNOWN;
                        break;
                }
        }
}

/* Enable memory controller ECC detection */
static void cpc925_mc_init(struct mem_ctl_info *mci)
{
        struct cpc925_mc_pdata *pdata = mci->pvt_info;
        u32 apimask;
        u32 mccr;

        /* Enable various ECC error exceptions */
        apimask = __raw_readl(pdata->vbase + REG_APIMASK_OFFSET);
        if ((apimask & ECC_MASK_ENABLE) == 0) {
                apimask |= ECC_MASK_ENABLE;
                __raw_writel(apimask, pdata->vbase + REG_APIMASK_OFFSET);
        }

        /* Enable ECC detection */
        mccr = __raw_readl(pdata->vbase + REG_MCCR_OFFSET);
        if ((mccr & MCCR_ECC_EN) == 0) {
                mccr |= MCCR_ECC_EN;
                __raw_writel(mccr, pdata->vbase + REG_MCCR_OFFSET);
        }
}

/* Disable memory controller ECC detection */
static void cpc925_mc_exit(struct mem_ctl_info *mci)
{
        /*
         * WARNING:
         * We are supposed to clear the ECC error detection bits,
         * and it will be no problem to do so. However, once they
         * are cleared here if we want to re-install CPC925 EDAC
         * module later, setting them up in cpc925_mc_init() will
         * trigger machine check exception.
         * Also, it's ok to leave ECC error detection bits enabled,
         * since they are reset to 1 by default or by boot loader.
         */

        return;
}

/*
 * Revert DDR column/row/bank addresses into page frame number and
 * offset in page.
 *
 * Suppose memory mode is 0x0111(128-bit mode, identical DIMM pairs),
 * physical address(PA) bits to column address(CA) bits mappings are:
 * CA   0   1   2   3   4   5   6   7   8   9   10
 * PA   59  58  57  56  55  54  53  52  51  50  49
 *
 * physical address(PA) bits to bank address(BA) bits mappings are:
 * BA   0   1
 * PA   43  44
 *
 * physical address(PA) bits to row address(RA) bits mappings are:
 * RA   0   1   2   3   4   5   6   7   8   9   10   11   12
 * PA   36  35  34  48  47  46  45  40  41  42  39   38   37
 */
static void cpc925_mc_get_pfn(struct mem_ctl_info *mci, u32 mear,
                unsigned long *pfn, unsigned long *offset, int *csrow)
{
        u32 bcnt, rank, col, bank, row;
        u32 c;
        unsigned long pa;
        int i;

        bcnt = (mear & MEAR_BCNT_MASK) >> MEAR_BCNT_SHIFT;
        rank = (mear & MEAR_RANK_MASK) >> MEAR_RANK_SHIFT;
        col = (mear & MEAR_COL_MASK) >> MEAR_COL_SHIFT;
        bank = (mear & MEAR_BANK_MASK) >> MEAR_BANK_SHIFT;
        row = mear & MEAR_ROW_MASK;

        *csrow = rank;

#ifdef CONFIG_EDAC_DEBUG
        if (mci->csrows[rank].first_page == 0) {
                cpc925_mc_printk(mci, KERN_ERR, "ECC occurs in a "
                        "non-populated csrow, broken hardware?\n");
                return;
        }
#endif

        /* Revert csrow number */
        pa = mci->csrows[rank].first_page << PAGE_SHIFT;

        /* Revert column address */
        col += bcnt;
        for (i = 0; i < 11; i++) {
                c = col & 0x1;
                col >>= 1;
                pa |= c << (14 - i);
        }

        /* Revert bank address */
        pa |= bank << 19;

        /* Revert row address, in 4 steps */
        for (i = 0; i < 3; i++) {
                c = row & 0x1;
                row >>= 1;
                pa |= c << (26 - i);
        }

        for (i = 0; i < 3; i++) {
                c = row & 0x1;
                row >>= 1;
                pa |= c << (21 + i);
        }

        for (i = 0; i < 4; i++) {
                c = row & 0x1;
                row >>= 1;
                pa |= c << (18 - i);
        }

        for (i = 0; i < 3; i++) {
                c = row & 0x1;
                row >>= 1;
                pa |= c << (29 - i);
        }

        *offset = pa & (PAGE_SIZE - 1);
        *pfn = pa >> PAGE_SHIFT;

        debugf0("%s: ECC physical address 0x%lx\n", __func__, pa);
}

static int cpc925_mc_find_channel(struct mem_ctl_info *mci, u16 syndrome)
{
        if ((syndrome & MESR_ECC_SYN_H_MASK) == 0)
                return 0;

        if ((syndrome & MESR_ECC_SYN_L_MASK) == 0)
                return 1;

        cpc925_mc_printk(mci, KERN_INFO, "Unexpected syndrome value: 0x%x\n",
                         syndrome);
        return 1;
}

/* Check memory controller registers for ECC errors */
static void cpc925_mc_check(struct mem_ctl_info *mci)
{
        struct cpc925_mc_pdata *pdata = mci->pvt_info;
        u32 apiexcp;
        u32 mear;
        u32 mesr;
        u16 syndrome;
        unsigned long pfn = 0, offset = 0;
        int csrow = 0, channel = 0;

        /* APIEXCP is cleared when read */
        apiexcp = __raw_readl(pdata->vbase + REG_APIEXCP_OFFSET);
        if ((apiexcp & ECC_EXCP_DETECTED) == 0)
                return;

        mesr = __raw_readl(pdata->vbase + REG_MESR_OFFSET);
        syndrome = mesr | (MESR_ECC_SYN_H_MASK | MESR_ECC_SYN_L_MASK);

        mear = __raw_readl(pdata->vbase + REG_MEAR_OFFSET);

        /* Revert column/row addresses into page frame number, etc */
        cpc925_mc_get_pfn(mci, mear, &pfn, &offset, &csrow);

        if (apiexcp & CECC_EXCP_DETECTED) {
                cpc925_mc_printk(mci, KERN_INFO, "DRAM CECC Fault\n");
                channel = cpc925_mc_find_channel(mci, syndrome);
                edac_mc_handle_ce(mci, pfn, offset, syndrome,
                                  csrow, channel, mci->ctl_name);
        }

        if (apiexcp & UECC_EXCP_DETECTED) {
                cpc925_mc_printk(mci, KERN_INFO, "DRAM UECC Fault\n");
                edac_mc_handle_ue(mci, pfn, offset, csrow, mci->ctl_name);
        }

        cpc925_mc_printk(mci, KERN_INFO, "Dump registers:\n");
        cpc925_mc_printk(mci, KERN_INFO, "APIMASK               0x%08x\n",
                __raw_readl(pdata->vbase + REG_APIMASK_OFFSET));
        cpc925_mc_printk(mci, KERN_INFO, "APIEXCP               0x%08x\n",
                apiexcp);
        cpc925_mc_printk(mci, KERN_INFO, "Mem Scrub Ctrl        0x%08x\n",
                __raw_readl(pdata->vbase + REG_MSCR_OFFSET));
        cpc925_mc_printk(mci, KERN_INFO, "Mem Scrub Rge Start   0x%08x\n",
                __raw_readl(pdata->vbase + REG_MSRSR_OFFSET));
        cpc925_mc_printk(mci, KERN_INFO, "Mem Scrub Rge End     0x%08x\n",
                __raw_readl(pdata->vbase + REG_MSRER_OFFSET));
        cpc925_mc_printk(mci, KERN_INFO, "Mem Scrub Pattern     0x%08x\n",
                __raw_readl(pdata->vbase + REG_MSPR_OFFSET));
        cpc925_mc_printk(mci, KERN_INFO, "Mem Chk Ctrl          0x%08x\n",
                __raw_readl(pdata->vbase + REG_MCCR_OFFSET));
        cpc925_mc_printk(mci, KERN_INFO, "Mem Chk Rge End       0x%08x\n",
                __raw_readl(pdata->vbase + REG_MCRER_OFFSET));
        cpc925_mc_printk(mci, KERN_INFO, "Mem Err Address       0x%08x\n",
                mesr);
        cpc925_mc_printk(mci, KERN_INFO, "Mem Err Syndrome      0x%08x\n",
                syndrome);
}

/******************** CPU err device********************************/
/* Enable CPU Errors detection */
static void cpc925_cpu_init(struct cpc925_dev_info *dev_info)
{
        u32 apimask;

        apimask = __raw_readl(dev_info->vbase + REG_APIMASK_OFFSET);
        if ((apimask & CPU_MASK_ENABLE) == 0) {
                apimask |= CPU_MASK_ENABLE;
                __raw_writel(apimask, dev_info->vbase + REG_APIMASK_OFFSET);
        }
}

/* Disable CPU Errors detection */
static void cpc925_cpu_exit(struct cpc925_dev_info *dev_info)
{
        /*
         * WARNING:
         * We are supposed to clear the CPU error detection bits,
         * and it will be no problem to do so. However, once they
         * are cleared here if we want to re-install CPC925 EDAC
         * module later, setting them up in cpc925_cpu_init() will
         * trigger machine check exception.
         * Also, it's ok to leave CPU error detection bits enabled,
         * since they are reset to 1 by default.
         */

        return;
}

/* Check for CPU Errors */
static void cpc925_cpu_check(struct edac_device_ctl_info *edac_dev)
{
        struct cpc925_dev_info *dev_info = edac_dev->pvt_info;
        u32 apiexcp;
        u32 apimask;

        /* APIEXCP is cleared when read */
        apiexcp = __raw_readl(dev_info->vbase + REG_APIEXCP_OFFSET);
        if ((apiexcp & CPU_EXCP_DETECTED) == 0)
                return;

        apimask = __raw_readl(dev_info->vbase + REG_APIMASK_OFFSET);
        cpc925_printk(KERN_INFO, "Processor Interface Fault\n"
                                 "Processor Interface register dump:\n");
        cpc925_printk(KERN_INFO, "APIMASK               0x%08x\n", apimask);
        cpc925_printk(KERN_INFO, "APIEXCP               0x%08x\n", apiexcp);

        edac_device_handle_ue(edac_dev, 0, 0, edac_dev->ctl_name);
}

/******************** HT Link err device****************************/
/* Enable HyperTransport Link Error detection */
static void cpc925_htlink_init(struct cpc925_dev_info *dev_info)
{
        u32 ht_errctrl;

        ht_errctrl = __raw_readl(dev_info->vbase + REG_ERRCTRL_OFFSET);
        if ((ht_errctrl & HT_ERRCTRL_ENABLE) == 0) {
                ht_errctrl |= HT_ERRCTRL_ENABLE;
                __raw_writel(ht_errctrl, dev_info->vbase + REG_ERRCTRL_OFFSET);
        }
}

/* Disable HyperTransport Link Error detection */
static void cpc925_htlink_exit(struct cpc925_dev_info *dev_info)
{
        u32 ht_errctrl;

        ht_errctrl = __raw_readl(dev_info->vbase + REG_ERRCTRL_OFFSET);
        ht_errctrl &= ~HT_ERRCTRL_ENABLE;
        __raw_writel(ht_errctrl, dev_info->vbase + REG_ERRCTRL_OFFSET);
}

/* Check for HyperTransport Link errors */
static void cpc925_htlink_check(struct edac_device_ctl_info *edac_dev)
{
        struct cpc925_dev_info *dev_info = edac_dev->pvt_info;
        u32 brgctrl = __raw_readl(dev_info->vbase + REG_BRGCTRL_OFFSET);
        u32 linkctrl = __raw_readl(dev_info->vbase + REG_LINKCTRL_OFFSET);
        u32 errctrl = __raw_readl(dev_info->vbase + REG_ERRCTRL_OFFSET);
        u32 linkerr = __raw_readl(dev_info->vbase + REG_LINKERR_OFFSET);

        if (!((brgctrl & BRGCTRL_DETSERR) ||
              (linkctrl & HT_LINKCTRL_DETECTED) ||
              (errctrl & HT_ERRCTRL_DETECTED) ||
              (linkerr & HT_LINKERR_DETECTED)))
                return;

        cpc925_printk(KERN_INFO, "HT Link Fault\n"
                                 "HT register dump:\n");
        cpc925_printk(KERN_INFO, "Bridge Ctrl                   0x%08x\n",
                      brgctrl);
        cpc925_printk(KERN_INFO, "Link Config Ctrl              0x%08x\n",
                      linkctrl);
        cpc925_printk(KERN_INFO, "Error Enum and Ctrl           0x%08x\n",
                      errctrl);
        cpc925_printk(KERN_INFO, "Link Error                    0x%08x\n",
                      linkerr);

        /* Clear by write 1 */
        if (brgctrl & BRGCTRL_DETSERR)
                __raw_writel(BRGCTRL_DETSERR,
                                dev_info->vbase + REG_BRGCTRL_OFFSET);

        if (linkctrl & HT_LINKCTRL_DETECTED)
                __raw_writel(HT_LINKCTRL_DETECTED,
                                dev_info->vbase + REG_LINKCTRL_OFFSET);

        /* Initiate Secondary Bus Reset to clear the chain failure */
        if (errctrl & ERRCTRL_CHN_FAL)
                __raw_writel(BRGCTRL_SECBUSRESET,
                                dev_info->vbase + REG_BRGCTRL_OFFSET);

        if (errctrl & ERRCTRL_RSP_ERR)
                __raw_writel(ERRCTRL_RSP_ERR,
                                dev_info->vbase + REG_ERRCTRL_OFFSET);

        if (linkerr & HT_LINKERR_DETECTED)
                __raw_writel(HT_LINKERR_DETECTED,
                                dev_info->vbase + REG_LINKERR_OFFSET);

        edac_device_handle_ce(edac_dev, 0, 0, edac_dev->ctl_name);
}

static struct cpc925_dev_info cpc925_devs[] = {
        {
        .ctl_name = CPC925_CPU_ERR_DEV,
        .init = cpc925_cpu_init,
        .exit = cpc925_cpu_exit,
        .check = cpc925_cpu_check,
        },
        {
        .ctl_name = CPC925_HT_LINK_DEV,
        .init = cpc925_htlink_init,
        .exit = cpc925_htlink_exit,
        .check = cpc925_htlink_check,
        },
        {0}, /* Terminated by NULL */
};

/*
 * Add CPU Err detection and HyperTransport Link Err detection
 * as common "edac_device", they have no corresponding device
 * nodes in the Open Firmware DTB and we have to add platform
 * devices for them. Also, they will share the MMIO with that
 * of memory controller.
 */
static void cpc925_add_edac_devices(void __iomem *vbase)
{
        struct cpc925_dev_info *dev_info;

        if (!vbase) {
                cpc925_printk(KERN_ERR, "MMIO not established yet\n");
                return;
        }

        for (dev_info = &cpc925_devs[0]; dev_info->init; dev_info++) {
                dev_info->vbase = vbase;
                dev_info->pdev = platform_device_register_simple(
                                        dev_info->ctl_name, 0, NULL, 0);
                if (IS_ERR(dev_info->pdev)) {
                        cpc925_printk(KERN_ERR,
                                "Can't register platform device for %s\n",
                                dev_info->ctl_name);
                        continue;
                }

                /*
                 * Don't have to allocate private structure but
                 * make use of cpc925_devs[] instead.
                 */
                dev_info->edac_idx = edac_device_alloc_index();
                dev_info->edac_dev =
                        edac_device_alloc_ctl_info(0, dev_info->ctl_name,
                                1, NULL, 0, 0, NULL, 0, dev_info->edac_idx);
                if (!dev_info->edac_dev) {
                        cpc925_printk(KERN_ERR, "No memory for edac device\n");
                        goto err1;
                }

                dev_info->edac_dev->pvt_info = dev_info;
                dev_info->edac_dev->dev = &dev_info->pdev->dev;
                dev_info->edac_dev->ctl_name = dev_info->ctl_name;
                dev_info->edac_dev->mod_name = CPC925_EDAC_MOD_STR;
                dev_info->edac_dev->dev_name = dev_name(&dev_info->pdev->dev);

                if (edac_op_state == EDAC_OPSTATE_POLL)
                        dev_info->edac_dev->edac_check = dev_info->check;

                if (dev_info->init)
                        dev_info->init(dev_info);

                if (edac_device_add_device(dev_info->edac_dev) > 0) {
                        cpc925_printk(KERN_ERR,
                                "Unable to add edac device for %s\n",
                                dev_info->ctl_name);
                        goto err2;
                }

                debugf0("%s: Successfully added edac device for %s\n",
                        __func__, dev_info->ctl_name);

                continue;

err2:
                if (dev_info->exit)
                        dev_info->exit(dev_info);
                edac_device_free_ctl_info(dev_info->edac_dev);
err1:
                platform_device_unregister(dev_info->pdev);
        }
}

/*
 * Delete the common "edac_device" for CPU Err Detection
 * and HyperTransport Link Err Detection
 */
static void cpc925_del_edac_devices(void)
{
        struct cpc925_dev_info *dev_info;

        for (dev_info = &cpc925_devs[0]; dev_info->init; dev_info++) {
                if (dev_info->edac_dev) {
                        edac_device_del_device(dev_info->edac_dev->dev);
                        edac_device_free_ctl_info(dev_info->edac_dev);
                        platform_device_unregister(dev_info->pdev);
                }

                if (dev_info->exit)
                        dev_info->exit(dev_info);

                debugf0("%s: Successfully deleted edac device for %s\n",
                        __func__, dev_info->ctl_name);
        }
}

/* Convert current back-ground scrub rate into byte/sec bandwidth */
static int cpc925_get_sdram_scrub_rate(struct mem_ctl_info *mci)
{
        struct cpc925_mc_pdata *pdata = mci->pvt_info;
        int bw;
        u32 mscr;
        u8 si;

        mscr = __raw_readl(pdata->vbase + REG_MSCR_OFFSET);
        si = (mscr & MSCR_SI_MASK) >> MSCR_SI_SHIFT;

        debugf0("%s, Mem Scrub Ctrl Register 0x%x\n", __func__, mscr);

        if (((mscr & MSCR_SCRUB_MOD_MASK) != MSCR_BACKGR_SCRUB) ||
            (si == 0)) {
                cpc925_mc_printk(mci, KERN_INFO, "Scrub mode not enabled\n");
                bw = 0;
        } else
                bw = CPC925_SCRUB_BLOCK_SIZE * 0xFA67 / si;

        return bw;
}

/* Return 0 for single channel; 1 for dual channel */
static int cpc925_mc_get_channels(void __iomem *vbase)
{
        int dual = 0;
        u32 mbcr;

        mbcr = __raw_readl(vbase + REG_MBCR_OFFSET);

        /*
         * Dual channel only when 128-bit wide physical bus
         * and 128-bit configuration.
         */
        if (((mbcr & MBCR_64BITCFG_MASK) == 0) &&
            ((mbcr & MBCR_64BITBUS_MASK) == 0))
                dual = 1;

        debugf0("%s: %s channel\n", __func__,
                (dual > 0) ? "Dual" : "Single");

        return dual;
}

static int __devinit cpc925_probe(struct platform_device *pdev)
{
        static int edac_mc_idx;
        struct mem_ctl_info *mci;
        void __iomem *vbase;
        struct cpc925_mc_pdata *pdata;
        struct resource *r;
        int res = 0, nr_channels;

        debugf0("%s: %s platform device found!\n", __func__, pdev->name);

        if (!devres_open_group(&pdev->dev, cpc925_probe, GFP_KERNEL)) {
                res = -ENOMEM;
                goto out;
        }

        r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!r) {
                cpc925_printk(KERN_ERR, "Unable to get resource\n");
                res = -ENOENT;
                goto err1;
        }

        if (!devm_request_mem_region(&pdev->dev,
                                     r->start,
                                     resource_size(r),
                                     pdev->name)) {
                cpc925_printk(KERN_ERR, "Unable to request mem region\n");
                res = -EBUSY;
                goto err1;
        }

        vbase = devm_ioremap(&pdev->dev, r->start, resource_size(r));
        if (!vbase) {
                cpc925_printk(KERN_ERR, "Unable to ioremap device\n");
                res = -ENOMEM;
                goto err2;
        }

        nr_channels = cpc925_mc_get_channels(vbase);
        mci = edac_mc_alloc(sizeof(struct cpc925_mc_pdata),
                        CPC925_NR_CSROWS, nr_channels + 1, edac_mc_idx);
        if (!mci) {
                cpc925_printk(KERN_ERR, "No memory for mem_ctl_info\n");
                res = -ENOMEM;
                goto err2;
        }

        pdata = mci->pvt_info;
        pdata->vbase = vbase;
        pdata->edac_idx = edac_mc_idx++;
        pdata->name = pdev->name;

        mci->dev = &pdev->dev;
        platform_set_drvdata(pdev, mci);
        mci->dev_name = dev_name(&pdev->dev);
        mci->mtype_cap = MEM_FLAG_RDDR | MEM_FLAG_DDR;
        mci->edac_ctl_cap = EDAC_FLAG_NONE | EDAC_FLAG_SECDED;
        mci->edac_cap = EDAC_FLAG_SECDED;
        mci->mod_name = CPC925_EDAC_MOD_STR;
        mci->mod_ver = CPC925_EDAC_REVISION;
        mci->ctl_name = pdev->name;

        if (edac_op_state == EDAC_OPSTATE_POLL)
                mci->edac_check = cpc925_mc_check;

        mci->ctl_page_to_phys = NULL;
        mci->scrub_mode = SCRUB_SW_SRC;
        mci->set_sdram_scrub_rate = NULL;
        mci->get_sdram_scrub_rate = cpc925_get_sdram_scrub_rate;

        cpc925_init_csrows(mci);

        /* Setup memory controller registers */
        cpc925_mc_init(mci);

        if (edac_mc_add_mc(mci) > 0) {
                cpc925_mc_printk(mci, KERN_ERR, "Failed edac_mc_add_mc()\n");
                goto err3;
        }

        cpc925_add_edac_devices(vbase);

        /* get this far and it's successful */
        debugf0("%s: success\n", __func__);

        res = 0;
        goto out;

err3:
        cpc925_mc_exit(mci);
        edac_mc_free(mci);
err2:
        devm_release_mem_region(&pdev->dev, r->start, resource_size(r));
err1:
        devres_release_group(&pdev->dev, cpc925_probe);
out:
        return res;
}

static int cpc925_remove(struct platform_device *pdev)
{
        struct mem_ctl_info *mci = platform_get_drvdata(pdev);

        /*
         * Delete common edac devices before edac mc, because
         * the former share the MMIO of the latter.
         */
        cpc925_del_edac_devices();
        cpc925_mc_exit(mci);

        edac_mc_del_mc(&pdev->dev);
        edac_mc_free(mci);

        return 0;
}

static struct platform_driver cpc925_edac_driver = {
        .probe = cpc925_probe,
        .remove = cpc925_remove,
        .driver = {
                   .name = "cpc925_edac",
        }
};

static int __init cpc925_edac_init(void)
{
        int ret = 0;

        printk(KERN_INFO "IBM CPC925 EDAC driver " CPC925_EDAC_REVISION "\n");
        printk(KERN_INFO "\t(c) 2008 Wind River Systems, Inc\n");

        /* Only support POLL mode so far */
        edac_op_state = EDAC_OPSTATE_POLL;

        ret = platform_driver_register(&cpc925_edac_driver);

        if (ret) {
                printk(KERN_WARNING "Failed to register %s\n",
                        CPC925_EDAC_MOD_STR);
        }

        return ret;
}

static void __exit cpc925_edac_exit(void)
{
        platform_driver_unregister(&cpc925_edac_driver);
}

module_init(cpc925_edac_init);
module_exit(cpc925_edac_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Cao Qingtao <qingtao.cao@windriver.com>");
MODULE_DESCRIPTION("IBM CPC925 Bridge and MC EDAC kernel module");