Eric Lee / smarc-uboot

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common/ddr_spd.c 2.26 KB
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0f2cbe3f5   James Yang   Add proper SPD de... 
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  /*
   * Copyright 2008 Freescale Semiconductor, Inc.
   *
   * 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.
   */
  
  #include <common.h>
  #include <ddr_spd.h>
  
  /* used for ddr1 and ddr2 spd */
  static int
  spd_check(const u8 *buf, u8 spd_rev, u8 spd_cksum)
  {
  	unsigned int cksum = 0;
  	unsigned int i;
  
  	/*
  	 * Check SPD revision supported
c7fd27ccf   Kyle Moffett   mpc8xxx: DDR2/DDR... 
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  	 * Rev 1.X or less supported by this code
0f2cbe3f5   James Yang   Add proper SPD de... 
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  	 */
bcb6c2bb8   York Sun   Enabled support f... 
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  	if (spd_rev >= 0x20) {
0f2cbe3f5   James Yang   Add proper SPD de... 
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  		printf("SPD revision %02X not supported by this code
  ",
  		       spd_rev);
  		return 1;
  	}
bcb6c2bb8   York Sun   Enabled support f... 
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  	if (spd_rev > 0x13) {
  		printf("SPD revision %02X not verified by this code
  ",
  		       spd_rev);
  	}
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  	/*
  	 * Calculate checksum
  	 */
  	for (i = 0; i < 63; i++) {
  		cksum += *buf++;
  	}
  	cksum &= 0xFF;
  
  	if (cksum != spd_cksum) {
  		printf("SPD checksum unexpected. "
  			"Checksum in SPD = %02X, computed SPD = %02X
  ",
  			spd_cksum, cksum);
  		return 1;
  	}
  
  	return 0;
  }
  
  unsigned int
  ddr1_spd_check(const ddr1_spd_eeprom_t *spd)
  {
  	const u8 *p = (const u8 *)spd;
  
  	return spd_check(p, spd->spd_rev, spd->cksum);
  }
  
  unsigned int
  ddr2_spd_check(const ddr2_spd_eeprom_t *spd)
  {
  	const u8 *p = (const u8 *)spd;
  
  	return spd_check(p, spd->spd_rev, spd->cksum);
  }
c360ceac0   Dave Liu   fsl-ddr: add the ... 
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  /*
   * CRC16 compute for DDR3 SPD
   * Copied from DDR3 SPD spec.
   */
  static int
  crc16(char *ptr, int count)
  {
  	int crc, i;
  
  	crc = 0;
  	while (--count >= 0) {
  		crc = crc ^ (int)*ptr++ << 8;
  		for (i = 0; i < 8; ++i)
  			if (crc & 0x8000)
  				crc = crc << 1 ^ 0x1021;
  			else
  				crc = crc << 1;
  	}
  	return crc & 0xffff;
  }
  
  unsigned int
  ddr3_spd_check(const ddr3_spd_eeprom_t *spd)
  {
  	char *p = (char *)spd;
  	int csum16;
  	int len;
  	char crc_lsb;	/* byte 126 */
  	char crc_msb;	/* byte 127 */
  
  	/*
  	 * SPD byte0[7] - CRC coverage
  	 * 0 = CRC covers bytes 0~125
  	 * 1 = CRC covers bytes 0~116
  	 */
  
  	len = !(spd->info_size_crc & 0x80) ? 126 : 117;
  	csum16 = crc16(p, len);
  
  	crc_lsb = (char) (csum16 & 0xff);
  	crc_msb = (char) (csum16 >> 8);
  
  	if (spd->crc[0] == crc_lsb && spd->crc[1] == crc_msb) {
  		return 0;
  	} else {
  		printf("SPD checksum unexpected.
  "
  			"Checksum lsb in SPD = %02X, computed SPD = %02X
  "
  			"Checksum msb in SPD = %02X, computed SPD = %02X
  ",
  			spd->crc[0], crc_lsb, spd->crc[1], crc_msb);
  		return 1;
  	}
  }