1 files changed, 118 insertions, 0 deletions
diff --git a/u-boot/common/ddr_spd.c b/u-boot/common/ddr_spd.c
new file mode 100644
index 0000000..a7a30de
--- /dev/null
+++ b/u-boot/common/ddr_spd.c
@@ -0,0 +1,118 @@
+/*
+ * 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
+	 * Rev 1.2 or less supported by this code
+	 */
+	if (spd_rev >= 0x20) {
+		printf("SPD revision %02X not supported by this code\n",
+		       spd_rev);
+		return 1;
+	}
+	if (spd_rev > 0x13) {
+		printf("SPD revision %02X not verified by this code\n",
+		       spd_rev);
+	}
+
+	/*
+	 * 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\n",
+			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);
+}
+
+/*
+ * 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.\n"
+			"Checksum lsb in SPD = %02X, computed SPD = %02X\n"
+			"Checksum msb in SPD = %02X, computed SPD = %02X\n",
+			spd->crc[0], crc_lsb, spd->crc[1], crc_msb);
+		return 1;
+	}
+}