44x_spd_ddr.c

uboot详细解读可用启动引导LINUX2.6内核

/*
 * 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, [e-mail]
 *
 * Based on code by:
 *
 * Kenneth Johansson ,Ericsson AB.
 * [e-mail]
 *
 * 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, [e-mail]
 * Support for AMCC 440 based on OpenBIOS draminit.c from IBM.
 *
 * (C) Copyright 2005-2007
 * Stefan Roese, DENX Software Engineering, [e-mail].
 *
 * 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>

#include "ecc.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")));

/*-----------------------------------------------------------------------------+
  |  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
 * CONFIG_4xx_DCACHE in the board config file and this code should setup
 * everything correctly.
 */
#ifdef CONFIG_4xx_DCACHE
#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 const unsigned char cfg_simulate_spd_eeprom[128];
#endif

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);

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)
	/*
	 * 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.
	 */
	ecc_init(CFG_SDRAM_BASE, 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);