Subject: Re: [v2 PATCH 1/3] EDAC: Add CPC925 Memory Controller driver

From: Benjamin Herrenschmidt <[email-masked]>
Date: Thu, 30 Apr 2009 13:08:57 +1000

On Mon, 2009-04-13 at 14:05 +0800, Harry Ciao wrote:
> 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.

Ah, fun ! I'm pretty sure I wrote a driver for that chipset a while
ago ... looks like I forgot to merge it :-)

I'll review in more details asap

Thanks,
Ben.

> Signed-off-by: Harry Ciao <[email-masked]>
> ---
>  drivers/edac/Kconfig       |    9 +
>  drivers/edac/Makefile      |    1 +
>  drivers/edac/cpc925_edac.c | 1020 ++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 1030 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/edac/cpc925_edac.c
> 
> diff --git a/drivers/edac/Kconfig b/drivers/edac/Kconfig
> index 13ccec6..1a320b4 100644
> --- a/drivers/edac/Kconfig
> +++ b/drivers/edac/Kconfig
> @@ -188,4 +188,13 @@ config EDAC_AMD8131
>  	  Support for error detection and correction on the
>  	  AMD8131 HyperTransport PCI-X Tunnel chip.
>  
> +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 407601f..b4e0d86 100644
> --- a/drivers/edac/Makefile
> +++ b/drivers/edac/Makefile
> @@ -36,4 +36,5 @@ obj-$(CONFIG_EDAC_MV64X60)		+= mv64x60_edac.o
>  obj-$(CONFIG_EDAC_CELL)			+= cell_edac.o
>  obj-$(CONFIG_EDAC_AMD8111)		+= amd8111_edac.o
>  obj-$(CONFIG_EDAC_AMD8131)		+= amd8131_edac.o
> +obj-$(CONFIG_EDAC_CPC925)		+= cpc925_edac.o
>  
> diff --git a/drivers/edac/cpc925_edac.c b/drivers/edac/cpc925_edac.c
> new file mode 100644
> index 0000000..7236847
> --- /dev/null
> +++ b/drivers/edac/cpc925_edac.c
> @@ -0,0 +1,1020 @@
> +/*
> + * cpc925_edac.c, EDAC driver for IBM CPC925 Bridge and Memory Controller.
> + *
> + * Copyright (c) 2008 Wind River Systems, Inc.
> + *
> + * Authors:	Cao Qingtao <[email-masked]>
> + *
> + * 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);
> +};
> +
> +
> +static int edac_mc_idx;
> +
> +/* 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 & UECC_EXCP_DETECTED) {
> +		cpc925_mc_printk(mci, KERN_INFO, "DRAM UECC Fault\n");
> +		channel = cpc925_mc_find_channel(mci, syndrome);
> +		edac_mc_handle_ce(mci, pfn, offset, syndrome,
> +				  csrow, channel, mci->ctl_name);
> +	}
> +
> +	if (apiexcp & CECC_EXCP_DETECTED) {
> +		cpc925_mc_printk(mci, KERN_INFO, "DRAM CECC 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)
> +{
> +	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 <[email-masked]>");
> +MODULE_DESCRIPTION("IBM CPC925 Bridge and MC EDAC kernel module");