44x_spd_ddr.c

/*
 * cpu/ppc4xx/44x_spd_ddr.c
 * This SPD DDR detection code supports IBM/AMCC PPC44x cpu with a
 * DDR controller. Those are 440GP/GX/EP/GR.
 *
 * (C) Copyright 2001
 * Bill Hunter, Wave 7 Optics, williamhunter@attbi.com
 *
 * Based on code by:
 *
 * Kenneth Johansson ,Ericsson AB.
 * kenneth.johansson@etx.ericsson.se
 *
 * hacked up by bill hunter. fixed so we could run before
 * serial_init and console_init. previous version avoided this by
 * running out of cache memory during serial/console init, then running
 * this code later.
 *
 * (C) Copyright 2002
 * Jun Gu, Artesyn Technology, jung@artesyncp.com
 * Support for AMCC 440 based on OpenBIOS draminit.c from IBM.
 *
 * (C) Copyright 2005-2007
 * Stefan Roese, DENX Software Engineering, sr@denx.de.
 *
 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 *
 * 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
 */

/* define DEBUG for debugging output (obviously ;-)) */
#if 0
#define DEBUG
#endif

#include <common.h>
#include <asm/processor.h>
#include <i2c.h>
#include <ppc4xx.h>
#include <asm/mmu.h>

#if defined(CONFIG_SPD_EEPROM) &&					\
	(defined(CONFIG_440GP) || defined(CONFIG_440GX) ||		\
	 defined(CONFIG_440EP) || defined(CONFIG_440GR))

/*
 * Set default values
 */
#ifndef CFG_I2C_SPEED
#define CFG_I2C_SPEED	50000
#endif

#ifndef CFG_I2C_SLAVE
#define CFG_I2C_SLAVE	0xFE
#endif

#define ONE_BILLION	1000000000

/*
 * Board-specific Platform code can reimplement spd_ddr_init_hang () if needed
 */
void __spd_ddr_init_hang (void)
{
	hang ();
}
void spd_ddr_init_hang (void) __attribute__((weak, alias("__spd_ddr_init_hang")));

/*-----------------------------------------------------------------------------
  |  Memory Controller Options 0
  +-----------------------------------------------------------------------------*/
#define SDRAM_CFG0_DCEN		0x80000000	/* SDRAM Controller Enable	*/
#define SDRAM_CFG0_MCHK_MASK	0x30000000	/* Memory data errchecking mask */
#define SDRAM_CFG0_MCHK_NON	0x00000000	/* No ECC generation		*/
#define SDRAM_CFG0_MCHK_GEN	0x20000000	/* ECC generation		*/
#define SDRAM_CFG0_MCHK_CHK	0x30000000	/* ECC generation and checking	*/
#define SDRAM_CFG0_RDEN		0x08000000	/* Registered DIMM enable	*/
#define SDRAM_CFG0_PMUD		0x04000000	/* Page management unit		*/
#define SDRAM_CFG0_DMWD_MASK	0x02000000	/* DRAM width mask		*/
#define SDRAM_CFG0_DMWD_32	0x00000000	/* 32 bits			*/
#define SDRAM_CFG0_DMWD_64	0x02000000	/* 64 bits			*/
#define SDRAM_CFG0_UIOS_MASK	0x00C00000	/* Unused IO State		*/
#define SDRAM_CFG0_PDP		0x00200000	/* Page deallocation policy	*/

/*-----------------------------------------------------------------------------
  |  Memory Controller Options 1
  +-----------------------------------------------------------------------------*/
#define SDRAM_CFG1_SRE		0x80000000	/* Self-Refresh Entry		*/
#define SDRAM_CFG1_PMEN		0x40000000	/* Power Management Enable	*/

/*-----------------------------------------------------------------------------+
  |  SDRAM DEVPOT Options
  +-----------------------------------------------------------------------------*/
#define SDRAM_DEVOPT_DLL	0x80000000
#define SDRAM_DEVOPT_DS		0x40000000

/*-----------------------------------------------------------------------------+
  |  SDRAM MCSTS Options
  +-----------------------------------------------------------------------------*/
#define SDRAM_MCSTS_MRSC	0x80000000
#define SDRAM_MCSTS_SRMS	0x40000000
#define SDRAM_MCSTS_CIS		0x20000000

/*-----------------------------------------------------------------------------
  |  SDRAM Refresh Timer Register
  +-----------------------------------------------------------------------------*/
#define SDRAM_RTR_RINT_MASK	  0xFFFF0000
#define SDRAM_RTR_RINT_ENCODE(n)  (((n) << 16) & SDRAM_RTR_RINT_MASK)
#define sdram_HZ_to_ns(hertz)	  (1000000000/(hertz))

/*-----------------------------------------------------------------------------+
  |  SDRAM UABus Base Address Reg
  +-----------------------------------------------------------------------------*/
#define SDRAM_UABBA_UBBA_MASK	0x0000000F

/*-----------------------------------------------------------------------------+
  |  Memory Bank 0-7 configuration
  +-----------------------------------------------------------------------------*/
#define SDRAM_BXCR_SDBA_MASK	0xff800000	  /* Base address	      */
#define SDRAM_BXCR_SDSZ_MASK	0x000e0000	  /* Size		      */
#define SDRAM_BXCR_SDSZ_8	0x00020000	  /*   8M		      */
#define SDRAM_BXCR_SDSZ_16	0x00040000	  /*  16M		      */
#define SDRAM_BXCR_SDSZ_32	0x00060000	  /*  32M		      */
#define SDRAM_BXCR_SDSZ_64	0x00080000	  /*  64M		      */
#define SDRAM_BXCR_SDSZ_128	0x000a0000	  /* 128M		      */
#define SDRAM_BXCR_SDSZ_256	0x000c0000	  /* 256M		      */
#define SDRAM_BXCR_SDSZ_512	0x000e0000	  /* 512M		      */
#define SDRAM_BXCR_SDAM_MASK	0x0000e000	  /* Addressing mode	      */
#define SDRAM_BXCR_SDAM_1	0x00000000	  /*   Mode 1		      */
#define SDRAM_BXCR_SDAM_2	0x00002000	  /*   Mode 2		      */
#define SDRAM_BXCR_SDAM_3	0x00004000	  /*   Mode 3		      */
#define SDRAM_BXCR_SDAM_4	0x00006000	  /*   Mode 4		      */
#define SDRAM_BXCR_SDBE		0x00000001	  /* Memory Bank Enable	      */

/*-----------------------------------------------------------------------------+
  |  SDRAM TR0 Options
  +-----------------------------------------------------------------------------*/
#define SDRAM_TR0_SDWR_MASK	0x80000000
#define	 SDRAM_TR0_SDWR_2_CLK	0x00000000
#define	 SDRAM_TR0_SDWR_3_CLK	0x80000000
#define SDRAM_TR0_SDWD_MASK	0x40000000
#define	 SDRAM_TR0_SDWD_0_CLK	0x00000000
#define	 SDRAM_TR0_SDWD_1_CLK	0x40000000
#define SDRAM_TR0_SDCL_MASK	0x01800000
#define	 SDRAM_TR0_SDCL_2_0_CLK 0x00800000
#define	 SDRAM_TR0_SDCL_2_5_CLK 0x01000000
#define	 SDRAM_TR0_SDCL_3_0_CLK 0x01800000
#define SDRAM_TR0_SDPA_MASK	0x000C0000
#define	 SDRAM_TR0_SDPA_2_CLK	0x00040000
#define	 SDRAM_TR0_SDPA_3_CLK	0x00080000
#define	 SDRAM_TR0_SDPA_4_CLK	0x000C0000
#define SDRAM_TR0_SDCP_MASK	0x00030000
#define	 SDRAM_TR0_SDCP_2_CLK	0x00000000
#define	 SDRAM_TR0_SDCP_3_CLK	0x00010000
#define	 SDRAM_TR0_SDCP_4_CLK	0x00020000
#define	 SDRAM_TR0_SDCP_5_CLK	0x00030000
#define SDRAM_TR0_SDLD_MASK	0x0000C000
#define	 SDRAM_TR0_SDLD_1_CLK	0x00000000
#define	 SDRAM_TR0_SDLD_2_CLK	0x00004000
#define SDRAM_TR0_SDRA_MASK	0x0000001C
#define	 SDRAM_TR0_SDRA_6_CLK	0x00000000
#define	 SDRAM_TR0_SDRA_7_CLK	0x00000004
#define	 SDRAM_TR0_SDRA_8_CLK	0x00000008
#define	 SDRAM_TR0_SDRA_9_CLK	0x0000000C
#define	 SDRAM_TR0_SDRA_10_CLK	0x00000010
#define	 SDRAM_TR0_SDRA_11_CLK	0x00000014
#define	 SDRAM_TR0_SDRA_12_CLK	0x00000018
#define	 SDRAM_TR0_SDRA_13_CLK	0x0000001C
#define SDRAM_TR0_SDRD_MASK	0x00000003
#define	 SDRAM_TR0_SDRD_2_CLK	0x00000001
#define	 SDRAM_TR0_SDRD_3_CLK	0x00000002
#define	 SDRAM_TR0_SDRD_4_CLK	0x00000003

/*-----------------------------------------------------------------------------+
  |  SDRAM TR1 Options
  +-----------------------------------------------------------------------------*/
#define SDRAM_TR1_RDSS_MASK	0xC0000000
#define	 SDRAM_TR1_RDSS_TR0	0x00000000
#define	 SDRAM_TR1_RDSS_TR1	0x40000000
#define	 SDRAM_TR1_RDSS_TR2	0x80000000
#define	 SDRAM_TR1_RDSS_TR3	0xC0000000
#define SDRAM_TR1_RDSL_MASK	0x00C00000
#define	 SDRAM_TR1_RDSL_STAGE1	0x00000000
#define	 SDRAM_TR1_RDSL_STAGE2	0x00400000
#define	 SDRAM_TR1_RDSL_STAGE3	0x00800000
#define SDRAM_TR1_RDCD_MASK	0x00000800
#define	 SDRAM_TR1_RDCD_RCD_0_0 0x00000000
#define	 SDRAM_TR1_RDCD_RCD_1_2 0x00000800
#define SDRAM_TR1_RDCT_MASK	0x000001FF
#define	 SDRAM_TR1_RDCT_ENCODE(x)  (((x) << 0) & SDRAM_TR1_RDCT_MASK)
#define	 SDRAM_TR1_RDCT_DECODE(x)  (((x) & SDRAM_TR1_RDCT_MASK) >> 0)
#define	 SDRAM_TR1_RDCT_MIN	0x00000000
#define	 SDRAM_TR1_RDCT_MAX	0x000001FF

/*-----------------------------------------------------------------------------+
  |  SDRAM WDDCTR Options
  +-----------------------------------------------------------------------------*/
#define SDRAM_WDDCTR_WRCP_MASK	0xC0000000
#define	 SDRAM_WDDCTR_WRCP_0DEG	  0x00000000
#define	 SDRAM_WDDCTR_WRCP_90DEG  0x40000000
#define	 SDRAM_WDDCTR_WRCP_180DEG 0x80000000
#define SDRAM_WDDCTR_DCD_MASK	0x000001FF

/*-----------------------------------------------------------------------------+
  |  SDRAM CLKTR Options
  +-----------------------------------------------------------------------------*/
#define SDRAM_CLKTR_CLKP_MASK	0xC0000000
#define	 SDRAM_CLKTR_CLKP_0DEG	  0x00000000
#define	 SDRAM_CLKTR_CLKP_90DEG	  0x40000000
#define	 SDRAM_CLKTR_CLKP_180DEG  0x80000000
#define SDRAM_CLKTR_DCDT_MASK	0x000001FF

/*-----------------------------------------------------------------------------+
  |  SDRAM DLYCAL Options
  +-----------------------------------------------------------------------------*/
#define SDRAM_DLYCAL_DLCV_MASK	0x000003FC
#define	 SDRAM_DLYCAL_DLCV_ENCODE(x) (((x)<<2) & SDRAM_DLYCAL_DLCV_MASK)
#define	 SDRAM_DLYCAL_DLCV_DECODE(x) (((x) & SDRAM_DLYCAL_DLCV_MASK)>>2)

/*-----------------------------------------------------------------------------+
  |  General Definition
  +-----------------------------------------------------------------------------*/
#define DEFAULT_SPD_ADDR1	0x53
#define DEFAULT_SPD_ADDR2	0x52
#define MAXBANKS		4		/* at most 4 dimm banks */
#define MAX_SPD_BYTES		256
#define NUMHALFCYCLES		4
#define NUMMEMTESTS		8
#define NUMMEMWORDS		8
#define MAXBXCR			4
#define TRUE			1
#define FALSE			0

/*
 * This DDR2 setup code can dynamically setup the TLB entries for the DDR2 memory
 * region. Right now the cache should still be disabled in U-Boot because of the
 * EMAC driver, that need it's buffer descriptor to be located in non cached
 * memory.
 *
 * If at some time this restriction doesn't apply anymore, just define
 * CFG_ENABLE_SDRAM_CACHE in the board config file and this code should setup
 * everything correctly.
 */
#ifdef CFG_ENABLE_SDRAM_CACHE
#define MY_TLB_WORD2_I_ENABLE	0			/* enable caching on SDRAM */
#else
#define MY_TLB_WORD2_I_ENABLE	TLB_WORD2_I_ENABLE	/* disable caching on SDRAM */
#endif

/* bank_parms is used to sort the bank sizes by descending order */
struct bank_param {
	unsigned long cr;
	unsigned long bank_size_bytes;
};

typedef struct bank_param BANKPARMS;

#ifdef CFG_SIMULATE_SPD_EEPROM
extern unsigned char cfg_simulate_spd_eeprom[128];
#endif
void program_tlb(u32 phys_addr, u32 virt_addr, u32 size, u32 tlb_word2_i_value);

static unsigned char spd_read(uchar chip, uint addr);
static void get_spd_info(unsigned long *dimm_populated,
			 unsigned char *iic0_dimm_addr,
			 unsigned long num_dimm_banks);
static void check_mem_type(unsigned long *dimm_populated,
			   unsigned char *iic0_dimm_addr,
			   unsigned long num_dimm_banks);
static void check_volt_type(unsigned long *dimm_populated,
			    unsigned char *iic0_dimm_addr,
			    unsigned long num_dimm_banks);
static void program_cfg0(unsigned long *dimm_populated,
			 unsigned char *iic0_dimm_addr,
			 unsigned long  num_dimm_banks);
static void program_cfg1(unsigned long *dimm_populated,
			 unsigned char *iic0_dimm_addr,
			 unsigned long num_dimm_banks);
static void program_rtr(unsigned long *dimm_populated,
			unsigned char *iic0_dimm_addr,
			unsigned long num_dimm_banks);
static void program_tr0(unsigned long *dimm_populated,
			unsigned char *iic0_dimm_addr,
			unsigned long num_dimm_banks);
static void program_tr1(void);

#ifdef CONFIG_DDR_ECC
static void program_ecc(unsigned long num_bytes);
#endif

static unsigned long program_bxcr(unsigned long *dimm_populated,
				  unsigned char *iic0_dimm_addr,
				  unsigned long num_dimm_banks);

/*
 * This function is reading data from the DIMM module EEPROM over the SPD bus
 * and uses that to program the sdram controller.
 *
 * This works on boards that has the same schematics that the AMCC walnut has.
 *
 * BUG: Don't handle ECC memory
 * BUG: A few values in the TR register is currently hardcoded
 */
long int spd_sdram(void) {
	unsigned char iic0_dimm_addr[] = SPD_EEPROM_ADDRESS;
	unsigned long dimm_populated[sizeof(iic0_dimm_addr)];
	unsigned long total_size;
	unsigned long cfg0;
	unsigned long mcsts;
	unsigned long num_dimm_banks;		    /* on board dimm banks */

	num_dimm_banks = sizeof(iic0_dimm_addr);

	/*
	 * Make sure I2C controller is initialized
	 * before continuing.
	 */
	i2c_init(CFG_I2C_SPEED, CFG_I2C_SLAVE);

	/*
	 * Read the SPD information using I2C interface. Check to see if the
	 * DIMM slots are populated.
	 */
	get_spd_info(dimm_populated, iic0_dimm_addr, num_dimm_banks);

	/*
	 * Check the memory type for the dimms plugged.
	 */
	check_mem_type(dimm_populated, iic0_dimm_addr, num_dimm_banks);

	/*
	 * Check the voltage type for the dimms plugged.
	 */
	check_volt_type(dimm_populated, iic0_dimm_addr, num_dimm_banks);

#if defined(CONFIG_440GX) || defined(CONFIG_440EP) || defined(CONFIG_440GR) || defined(CONFIG_440SP)
	/*
	 * Soft-reset SDRAM controller.
	 */
	mtsdr(sdr_srst, SDR0_SRST_DMC);
	mtsdr(sdr_srst, 0x00000000);
#endif

	/*
	 * program 440GP SDRAM controller options (SDRAM0_CFG0)
	 */
	program_cfg0(dimm_populated, iic0_dimm_addr, num_dimm_banks);

	/*
	 * program 440GP SDRAM controller options (SDRAM0_CFG1)
	 */
	program_cfg1(dimm_populated, iic0_dimm_addr, num_dimm_banks);

	/*
	 * program SDRAM refresh register (SDRAM0_RTR)
	 */
	program_rtr(dimm_populated, iic0_dimm_addr, num_dimm_banks);

	/*
	 * program SDRAM Timing Register 0 (SDRAM0_TR0)
	 */
	program_tr0(dimm_populated, iic0_dimm_addr, num_dimm_banks);

	/*
	 * program the BxCR registers to find out total sdram installed
	 */
	total_size = program_bxcr(dimm_populated, iic0_dimm_addr,
				  num_dimm_banks);

#ifdef CONFIG_PROG_SDRAM_TLB /* this define should eventually be removed */
	/* and program tlb entries for this size (dynamic) */
	program_tlb(0, 0, total_size, MY_TLB_WORD2_I_ENABLE);
#endif

	/*
	 * program SDRAM Clock Timing Register (SDRAM0_CLKTR)
	 */
	mtsdram(mem_clktr, 0x40000000);

	/*
	 * delay to ensure 200 usec has elapsed
	 */
	udelay(400);

	/*
	 * enable the memory controller
	 */
	mfsdram(mem_cfg0, cfg0);
	mtsdram(mem_cfg0, cfg0 | SDRAM_CFG0_DCEN);

	/*
	 * wait for SDRAM_CFG0_DC_EN to complete
	 */
	while (1) {
		mfsdram(mem_mcsts, mcsts);
		if ((mcsts & SDRAM_MCSTS_MRSC) != 0)
			break;
	}

	/*
	 * program SDRAM Timing Register 1, adding some delays
	 */
	program_tr1();

#ifdef CONFIG_DDR_ECC
	/*
	 * If ecc is enabled, initialize the parity bits.
	 */
	program_ecc(total_size);
#endif

	return total_size;
}

static unsigned char spd_read(uchar chip, uint addr)
{
	unsigned char data[2];

#ifdef CFG_SIMULATE_SPD_EEPROM
	if (chip == CFG_SIMULATE_SPD_EEPROM) {
		/*
		 * Onboard spd eeprom requested -> simulate values
		 */
		return cfg_simulate_spd_eeprom[addr];
	}
#endif /* CFG_SIMULATE_SPD_EEPROM */

	if (i2c_probe(chip) == 0) {
		if (i2c_read(chip, addr, 1, data, 1) == 0) {
			return data[0];
		}
	}

	return 0;
}

static void get_spd_info(unsigned long *dimm_populated,
			 unsigned char *iic0_dimm_addr,
			 unsigned long num_dimm_banks)
{
	unsigned long dimm_num;
	unsigned long dimm_found;
	unsigned char num_of_bytes;
	unsigned char total_size;

	dimm_found = FALSE;
	for (dimm_num = 0; dimm_num < num_dimm_banks; dimm_num++) {
		num_of_bytes = 0;
		total_size = 0;

		num_of_bytes = spd_read(iic0_dimm_addr[dimm_num], 0);
		total_size = spd_read(iic0_dimm_addr[dimm_num], 1);

		if ((num_of_bytes != 0) && (total_size != 0)) {
			dimm_populated[dimm_num] = TRUE;
			dimm_found = TRUE;
			debug("DIMM slot %lu: populated\n", dimm_num);
		} else {
			dimm_populated[dimm_num] = FALSE;
			debug("DIMM slot %lu: Not populated\n", dimm_num);
		}
	}

	if (dimm_found == FALSE) {
		printf("ERROR - No memory installed. Install a DDR-SDRAM DIMM.\n\n");
		spd_ddr_init_hang ();
	}
}

static void check_mem_type(unsigned long *dimm_populated,
			   unsigned char *iic0_dimm_addr,
			   unsigned long num_dimm_banks)
{
	unsigned long dimm_num;
	unsigned char dimm_type;

	for (dimm_num = 0; dimm_num < num_dimm_banks; dimm_num++) {
		if (dimm_populated[dimm_num] == TRUE) {
			dimm_type = spd_read(iic0_dimm_addr[dimm_num], 2);
			switch (dimm_type) {
			case 7:
				debug("DIMM slot %lu: DDR SDRAM detected\n", dimm_num);
				break;
			default:
				printf("ERROR: Unsupported DIMM detected in slot %lu.\n",
				       dimm_num);
				printf("Only DDR SDRAM DIMMs are supported.\n");
				printf("Replace the DIMM module with a supported DIMM.\n\n");
				spd_ddr_init_hang ();
				break;
			}
		}
	}
}

static void check_volt_type(unsigned long *dimm_populated,
			    unsigned char *iic0_dimm_addr,
			    unsigned long num_dimm_banks)
{
	unsigned long dimm_num;
	unsigned long voltage_type;

	for (dimm_num = 0; dimm_num < num_dimm_banks; dimm_num++) {
		if (dimm_populated[dimm_num] == TRUE) {
			voltage_type = spd_read(iic0_dimm_addr[dimm_num], 8);
			if (voltage_type != 0x04) {
				printf("ERROR: DIMM %lu with unsupported voltage level.\n",
				       dimm_num);
				spd_ddr_init_hang ();
			} else {
				debug("DIMM %lu voltage level supported.\n", dimm_num);
			}
			break;
		}
	}
}

static void program_cfg0(unsigned long *dimm_populated,
			 unsigned char *iic0_dimm_addr,
			 unsigned long num_dimm_banks)
{
	unsigned long dimm_num;
	unsigned long cfg0;
	unsigned long ecc_enabled;
	unsigned char ecc;
	unsigned char attributes;
	unsigned long data_width;
	unsigned long dimm_32bit;
	unsigned long dimm_64bit;

	/*
	 * get Memory Controller Options 0 data
	 */
	mfsdram(mem_cfg0, cfg0);

	/*
	 * clear bits
	 */
	cfg0 &= ~(SDRAM_CFG0_DCEN | SDRAM_CFG0_MCHK_MASK |
		  SDRAM_CFG0_RDEN | SDRAM_CFG0_PMUD |
		  SDRAM_CFG0_DMWD_MASK |
		  SDRAM_CFG0_UIOS_MASK | SDRAM_CFG0_PDP);


	/*
	 * FIXME: assume the DDR SDRAMs in both banks are the same
	 */
	ecc_enabled = TRUE;
	for (dimm_num = 0; dimm_num < num_dimm_banks; dimm_num++) {
		if (dimm_populated[dimm_num] == TRUE) {
			ecc = spd_read(iic0_dimm_addr[dimm_num], 11);
			if (ecc != 0x02) {
				ecc_enabled = FALSE;
			}

			/*
			 * program Registered DIMM Enable
			 */
			attributes = spd_read(iic0_dimm_addr[dimm_num], 21);
			if ((attributes & 0x02) != 0x00) {
				cfg0 |= SDRAM_CFG0_RDEN;
			}

			/*
			 * program DDR SDRAM Data Width
			 */
			data_width =
				(unsigned long)spd_read(iic0_dimm_addr[dimm_num],6) +
				(((unsigned long)spd_read(iic0_dimm_addr[dimm_num],7)) << 8);
			if (data_width == 64 || data_width == 72) {
				dimm_64bit = TRUE;
				cfg0 |= SDRAM_CFG0_DMWD_64;
			} else if (data_width == 32 || data_width == 40) {
				dimm_32bit = TRUE;
				cfg0 |= SDRAM_CFG0_DMWD_32;
			} else {
				printf("WARNING: DIMM with datawidth of %lu bits.\n",
				       data_width);
				printf("Only DIMMs with 32 or 64 bit datawidths supported.\n");
				spd_ddr_init_hang ();
			}
			break;
		}
	}

	/*
	 * program Memory Data Error Checking
	 */
	if (ecc_enabled == TRUE) {
		cfg0 |= SDRAM_CFG0_MCHK_GEN;
	} else {
		cfg0 |= SDRAM_CFG0_MCHK_NON;
	}

	/*
	 * program Page Management Unit (0 == enabled)
	 */
	cfg0 &= ~SDRAM_CFG0_PMUD;

	/*
	 * program Memory Controller Options 0
	 * Note: DCEN must be enabled after all DDR SDRAM controller
	 * configuration registers get initialized.
	 */
	mtsdram(mem_cfg0, cfg0);
}

static void program_cfg1(unsigned long *dimm_populated,
			 unsigned char *iic0_dimm_addr,
			 unsigned long num_dimm_banks)
{
	unsigned long cfg1;
	mfsdram(mem_cfg1, cfg1);

	/*
	 * Self-refresh exit, disable PM
	 */
	cfg1 &= ~(SDRAM_CFG1_SRE | SDRAM_CFG1_PMEN);

	/*
	 * program Memory Controller Options 1
	 */
	mtsdram(mem_cfg1, cfg1);
}

static void program_rtr(unsigned long *dimm_populated,
			unsigned char *iic0_dimm_addr,
			unsigned long num_dimm_banks)
{
	unsigned long dimm_num;
	unsigned long bus_period_x_10;
	unsigned long refresh_rate = 0;
	unsigned char refresh_rate_type;
	unsigned long refresh_interval;
	unsigned long sdram_rtr;
	PPC440_SYS_INFO sys_info;

	/*
	 * get the board info
	 */
	get_sys_info(&sys_info);
	bus_period_x_10 = ONE_BILLION / (sys_info.freqPLB / 10);

	for (dimm_num = 0;  dimm_num < num_dimm_banks; dimm_num++) {
		if (dimm_populated[dimm_num] == TRUE) {
			refresh_rate_type = 0x7F & spd_read(iic0_dimm_addr[dimm_num], 12);
			switch (refresh_rate_type) {
			case 0x00:
				refresh_rate = 15625;
				break;
			case 0x01:
				refresh_rate = 15625/4;
				break;
			case 0x02:
				refresh_rate = 15625/2;
				break;
			case 0x03:
				refresh_rate = 15626*2;
				break;
			case 0x04:
				refresh_rate = 15625*4;
				break;
			case 0x05:
				refresh_rate = 15625*8;
				break;
			default:
				printf("ERROR: DIMM %lu, unsupported refresh rate/type.\n",
				       dimm_num);
				printf("Replace the DIMM module with a supported DIMM.\n");
				break;
			}

			break;
		}
	}

	refresh_interval = refresh_rate * 10 / bus_period_x_10;
	sdram_rtr = (refresh_interval & 0x3ff8) <<  16;

	/*
	 * program Refresh Timer Register (SDRAM0_RTR)
	 */
	mtsdram(mem_rtr, sdram_rtr);
}

static void program_tr0(unsigned long *dimm_populated,
			 unsigned char *iic0_dimm_addr,
			 unsigned long num_dimm_banks)
{
	unsigned long dimm_num;
	unsigned long tr0;
	unsigned char wcsbc;
	unsigned char t_rp_ns;
	unsigned char t_rcd_ns;
	unsigned char t_ras_ns;
	unsigned long t_rp_clk;
	unsigned long t_ras_rcd_clk;
	unsigned long t_rcd_clk;
	unsigned long t_rfc_clk;
	unsigned long plb_check;
	unsigned char cas_bit;
	unsigned long cas_index;
	unsigned char cas_2_0_available;
	unsigned char cas_2_5_available;
	unsigned char cas_3_0_available;
	unsigned long cycle_time_ns_x_10[3];
	unsigned long tcyc_3_0_ns_x_10;
	unsigned long tcyc_2_5_ns_x_10;
	unsigned long tcyc_2_0_ns_x_10;
	unsigned long tcyc_reg;
	unsigned long bus_period_x_10;
	PPC440_SYS_INFO sys_info;
	unsigned long residue;

	/*
	 * get the board info
	 */
	get_sys_info(&sys_info);
	bus_period_x_10 = ONE_BILLION / (sys_info.freqPLB / 10);

	/*
	 * get SDRAM Timing Register 0 (SDRAM_TR0) and clear bits
	 */
	mfsdram(mem_tr0, tr0);
	tr0 &= ~(SDRAM_TR0_SDWR_MASK | SDRAM_TR0_SDWD_MASK |
		 SDRAM_TR0_SDCL_MASK | SDRAM_TR0_SDPA_MASK |
		 SDRAM_TR0_SDCP_MASK | SDRAM_TR0_SDLD_MASK |
		 SDRAM_TR0_SDRA_MASK | SDRAM_TR0_SDRD_MASK);

	/*
	 * initialization
	 */
	wcsbc = 0;
	t_rp_ns = 0;
	t_rcd_ns = 0;
	t_ras_ns = 0;
	cas_2_0_available = TRUE;
	cas_2_5_available = TRUE;
	cas_3_0_available = TRUE;
	tcyc_2_0_ns_x_10 = 0;
	tcyc_2_5_ns_x_10 = 0;
	tcyc_3_0_ns_x_10 = 0;

	for (dimm_num = 0; dimm_num < num_dimm_banks; dimm_num++) {
		if (dimm_populated[dimm_num] == TRUE) {
			wcsbc = spd_read(iic0_dimm_addr[dimm_num], 15);
			t_rp_ns	 = spd_read(iic0_dimm_addr[dimm_num], 27) >> 2;
			t_rcd_ns = spd_read(iic0_dimm_addr[dimm_num], 29) >> 2;
			t_ras_ns = spd_read(iic0_dimm_addr[dimm_num], 30);
			cas_bit = spd_read(iic0_dimm_addr[dimm_num], 18);

			for (cas_index = 0; cas_index < 3; cas_index++) {
				switch (cas_index) {
				case 0:
					tcyc_reg = spd_read(iic0_dimm_addr[dimm_num], 9);
					break;
				case 1:
					tcyc_reg = spd_read(iic0_dimm_addr[dimm_num], 23);
					break;
				default:
					tcyc_reg = spd_read(iic0_dimm_addr[dimm_num], 25);
					break;
				}

				if ((tcyc_reg & 0x0F) >= 10) {
					printf("ERROR: Tcyc incorrect for DIMM in slot %lu\n",
					       dimm_num);
					spd_ddr_init_hang ();
				}

				cycle_time_ns_x_10[cas_index] =
					(((tcyc_reg & 0xF0) >> 4) * 10) + (tcyc_reg & 0x0F);
			}

			cas_index = 0;

			if ((cas_bit & 0x80) != 0) {
				cas_index += 3;
			} else if ((cas_bit & 0x40) != 0) {
				cas_index += 2;
			} else if ((cas_bit & 0x20) != 0) {
				cas_index += 1;
			}

			if (((cas_bit & 0x10) != 0) && (cas_index < 3)) {
				tcyc_3_0_ns_x_10 = cycle_time_ns_x_10[cas_index];
				cas_index++;
			} else {
				if (cas_index != 0) {
					cas_index++;
				}
				cas_3_0_available = FALSE;
			}

			if (((cas_bit & 0x08) != 0) || (cas_index < 3)) {
				tcyc_2_5_ns_x_10 = cycle_time_ns_x_10[cas_index];
				cas_index++;
			} else {
				if (cas_index != 0) {
					cas_index++;
				}
				cas_2_5_available = FALSE;
			}

			if (((cas_bit & 0x04) != 0) || (cas_index < 3)) {
				tcyc_2_0_ns_x_10 = cycle_time_ns_x_10[cas_index];
				cas_index++;
			} else {
				if (cas_index != 0) {
					cas_index++;
				}
				cas_2_0_available = FALSE;
			}

			break;
		}
	}

	/*
	 * Program SD_WR and SD_WCSBC fields
	 */
	tr0 |= SDRAM_TR0_SDWR_2_CLK;		    /* Write Recovery: 2 CLK */
	switch (wcsbc) {
	case 0:
		tr0 |= SDRAM_TR0_SDWD_0_CLK;
		break;
	default:
		tr0 |= SDRAM_TR0_SDWD_1_CLK;
		break;
	}

	/*
	 * Program SD_CASL field
	 */
	if ((cas_2_0_available == TRUE) &&
	    (bus_period_x_10 >= tcyc_2_0_ns_x_10)) {
		tr0 |= SDRAM_TR0_SDCL_2_0_CLK;
	} else if ((cas_2_5_available == TRUE) &&
		 (bus_period_x_10 >= tcyc_2_5_ns_x_10)) {
		tr0 |= SDRAM_TR0_SDCL_2_5_CLK;
	} else if ((cas_3_0_available == TRUE) &&
		 (bus_period_x_10 >= tcyc_3_0_ns_x_10)) {
		tr0 |= SDRAM_TR0_SDCL_3_0_CLK;
	} else {
		printf("ERROR: No supported CAS latency with the installed DIMMs.\n");
		printf("Only CAS latencies of 2.0, 2.5, and 3.0 are supported.\n");
		printf("Make sure the PLB speed is within the supported range.\n");
		spd_ddr_init_hang ();
	}

	/*
	 * Calculate Trp in clock cycles and round up if necessary
	 * Program SD_PTA field
	 */
	t_rp_clk = sys_info.freqPLB * t_rp_ns / ONE_BILLION;
	plb_check = ONE_BILLION * t_rp_clk / t_rp_ns;
	if (sys_info.freqPLB != plb_check) {
		t_rp_clk++;
	}
	switch ((unsigned long)t_rp_clk) {
	case 0:
	case 1:
	case 2:
		tr0 |= SDRAM_TR0_SDPA_2_CLK;
		break;
	case 3:
		tr0 |= SDRAM_TR0_SDPA_3_CLK;
		break;
	default:
		tr0 |= SDRAM_TR0_SDPA_4_CLK;
		break;
	}

	/*
	 * Program SD_CTP field
	 */
	t_ras_rcd_clk = sys_info.freqPLB * (t_ras_ns - t_rcd_ns) / ONE_BILLION;
	plb_check = ONE_BILLION * t_ras_rcd_clk / (t_ras_ns - t_rcd_ns);
	if (sys_info.freqPLB != plb_check) {
		t_ras_rcd_clk++;
	}
	switch (t_ras_rcd_clk) {
	case 0:
	case 1:
	case 2:
		tr0 |= SDRAM_TR0_SDCP_2_CLK;
		break;
	case 3:
		tr0 |= SDRAM_TR0_SDCP_3_CLK;
		break;
	case 4:
		tr0 |= SDRAM_TR0_SDCP_4_CLK;
		break;
	default:
		tr0 |= SDRAM_TR0_SDCP_5_CLK;
		break;
	}

	/*
	 * Program SD_LDF field
	 */
	tr0 |= SDRAM_TR0_SDLD_2_CLK;

	/*
	 * Program SD_RFTA field
	 * FIXME tRFC hardcoded as 75 nanoseconds
	 */
	t_rfc_clk = sys_info.freqPLB / (ONE_BILLION / 75);
	residue = sys_info.freqPLB % (ONE_BILLION / 75);
	if (residue >= (ONE_BILLION / 150)) {
		t_rfc_clk++;
	}
	switch (t_rfc_clk) {
	case 0:
	case 1:
	case 2:
	case 3:
	case 4:
	case 5:
	case 6:
		tr0 |= SDRAM_TR0_SDRA_6_CLK;
		break;
	case 7:
		tr0 |= SDRAM_TR0_SDRA_7_CLK;
		break;
	case 8:
		tr0 |= SDRAM_TR0_SDRA_8_CLK;
		break;
	case 9:
		tr0 |= SDRAM_TR0_SDRA_9_CLK;
		break;
	case 10:
		tr0 |= SDRAM_TR0_SDRA_10_CLK;
		break;
	case 11:
		tr0 |= SDRAM_TR0_SDRA_11_CLK;
		break;
	case 12:
		tr0 |= SDRAM_TR0_SDRA_12_CLK;
		break;
	default:
		tr0 |= SDRAM_TR0_SDRA_13_CLK;
		break;
	}

	/*
	 * Program SD_RCD field
	 */
	t_rcd_clk = sys_info.freqPLB * t_rcd_ns / ONE_BILLION;
	plb_check = ONE_BILLION * t_rcd_clk / t_rcd_ns;
	if (sys_info.freqPLB != plb_check) {
		t_rcd_clk++;
	}
	switch (t_rcd_clk) {
	case 0:
	case 1:
	case 2:
		tr0 |= SDRAM_TR0_SDRD_2_CLK;
		break;
	case 3:
		tr0 |= SDRAM_TR0_SDRD_3_CLK;
		break;
	default:
		tr0 |= SDRAM_TR0_SDRD_4_CLK;
		break;
	}

	debug("tr0: %x\n", tr0);
	mtsdram(mem_tr0, tr0);
}

static int short_mem_test(void)
{
	unsigned long i, j;
	unsigned long bxcr_num;
	unsigned long *membase;
	const unsigned long test[NUMMEMTESTS][NUMMEMWORDS] = {
		{0x00000000, 0x00000000, 0xFFFFFFFF, 0xFFFFFFFF,
		 0x00000000, 0x00000000, 0xFFFFFFFF, 0xFFFFFFFF},
		{0xFFFFFFFF, 0xFFFFFFFF, 0x00000000, 0x00000000,
		 0xFFFFFFFF, 0xFFFFFFFF, 0x00000000, 0x00000000},
		{0xAAAAAAAA, 0xAAAAAAAA, 0x55555555, 0x55555555,
		 0xAAAAAAAA, 0xAAAAAAAA, 0x55555555, 0x55555555},
		{0x55555555, 0x55555555, 0xAAAAAAAA, 0xAAAAAAAA,
		 0x55555555, 0x55555555, 0xAAAAAAAA, 0xAAAAAAAA},
		{0xA5A5A5A5, 0xA5A5A5A5, 0x5A5A5A5A, 0x5A5A5A5A,
		 0xA5A5A5A5, 0xA5A5A5A5, 0x5A5A5A5A, 0x5A5A5A5A},