edac: add CPC925 Memory Controller driver

Introduce IBM CPC925 EDAC driver, which makes use of ECC, CPU and
HyperTransport Link error detections and corrections on the IBM
CPC925 Bridge and Memory Controller.

[akpm@linux-foundation.org: cleanup]
Signed-off-by: Harry Ciao <qingtao.cao@windriver.com>
Cc: Doug Thompson <norsk5@yahoo.com>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Kumar Gala <galak@gate.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 1027 insertions, 0 deletions

diff --git a/drivers/edac/Kconfig b/drivers/edac/Kconfig
index ab4f3592a11c..ea3a75ee3fa3 100644
--- a/drivers/edac/Kconfig
+++ b/drivers/edac/Kconfig
@@ -232,4 +232,13 @@ config EDAC_AMD8111
           Note, add more Kconfig dependency if it's adopted
           on some machine other than Maple.
 
+config EDAC_CPC925
+        tristate "IBM CPC925 Memory Controller (PPC970FX)"
+        depends on EDAC_MM_EDAC && PPC64
+        help
+          Support for error detection and correction on the
+          IBM CPC925 Bridge and Memory Controller, which is
+          a companion chip to the PowerPC 970 family of
+          processors.
+
 endif # EDAC
diff --git a/drivers/edac/Makefile b/drivers/edac/Makefile
index 633dc5604ee3..98aa4a7db412 100644
--- a/drivers/edac/Makefile
+++ b/drivers/edac/Makefile
@@ -18,6 +18,7 @@ edac_core-objs	+= edac_pci.o edac_pci_sysfs.o
 endif
 
 obj-$(CONFIG_EDAC_AMD76X)               += amd76x_edac.o
+obj-$(CONFIG_EDAC_CPC925)               += cpc925_edac.o
 obj-$(CONFIG_EDAC_I5000)                += i5000_edac.o
 obj-$(CONFIG_EDAC_I5100)                += i5100_edac.o
 obj-$(CONFIG_EDAC_I5400)                += i5400_edac.o
diff --git a/drivers/edac/cpc925_edac.c b/drivers/edac/cpc925_edac.c
new file mode 100644
index 000000000000..8c54196b5aba
--- /dev/null
+++ b/drivers/edac/cpc925_edac.c
@@ -0,0 +1,1017 @@
+/*
+ * 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 "edac_core.h"
+#include "edac_module.h"
+
+#define CPC925_EDAC_REVISION    " Ver: 1.0.0 " __DATE__
+#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 bandwith */
+static int cpc925_get_sdram_scrub_rate(struct mem_ctl_info *mci, u32 *bw)
+{
+        struct cpc925_mc_pdata *pdata = mci->pvt_info;
+        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 0;
+}
+
+/* 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,
+                                     r->end - r->start + 1,
+                                     pdev->name)) {
+                cpc925_printk(KERN_ERR, "Unable to request mem region\n");
+                res = -EBUSY;
+                goto err1;
+        }
+
+        vbase = devm_ioremap(&pdev->dev, r->start, r->end - r->start + 1);
+        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, r->end-r->start+1);
+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");