1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright 2008-2014 Freescale Semiconductor, Inc.
4 */
5
6#include <common.h>
7#include <ddr_spd.h>
8
9/* used for ddr1 and ddr2 spd */
10static int
11spd_check(const u8 *buf, u8 spd_rev, u8 spd_cksum)
12{
13	unsigned int cksum = 0;
14	unsigned int i;
15
16	/*
17	 * Check SPD revision supported
18	 * Rev 1.X or less supported by this code
19	 */
20	if (spd_rev >= 0x20) {
21		printf("SPD revision %02X not supported by this code\n",
22		       spd_rev);
23		return 1;
24	}
25	if (spd_rev > 0x13) {
26		printf("SPD revision %02X not verified by this code\n",
27		       spd_rev);
28	}
29
30	/*
31	 * Calculate checksum
32	 */
33	for (i = 0; i < 63; i++) {
34		cksum += *buf++;
35	}
36	cksum &= 0xFF;
37
38	if (cksum != spd_cksum) {
39		printf("SPD checksum unexpected. "
40			"Checksum in SPD = %02X, computed SPD = %02X\n",
41			spd_cksum, cksum);
42		return 1;
43	}
44
45	return 0;
46}
47
48unsigned int
49ddr1_spd_check(const ddr1_spd_eeprom_t *spd)
50{
51	const u8 *p = (const u8 *)spd;
52
53	return spd_check(p, spd->spd_rev, spd->cksum);
54}
55
56unsigned int
57ddr2_spd_check(const ddr2_spd_eeprom_t *spd)
58{
59	const u8 *p = (const u8 *)spd;
60
61	return spd_check(p, spd->spd_rev, spd->cksum);
62}
63
64/*
65 * CRC16 compute for DDR3 SPD
66 * Copied from DDR3 SPD spec.
67 */
68static int
69crc16(char *ptr, int count)
70{
71	int crc, i;
72
73	crc = 0;
74	while (--count >= 0) {
75		crc = crc ^ (int)*ptr++ << 8;
76		for (i = 0; i < 8; ++i)
77			if (crc & 0x8000)
78				crc = crc << 1 ^ 0x1021;
79			else
80				crc = crc << 1;
81	}
82	return crc & 0xffff;
83}
84
85unsigned int
86ddr3_spd_check(const ddr3_spd_eeprom_t *spd)
87{
88	char *p = (char *)spd;
89	int csum16;
90	int len;
91	char crc_lsb;	/* byte 126 */
92	char crc_msb;	/* byte 127 */
93
94	/*
95	 * SPD byte0[7] - CRC coverage
96	 * 0 = CRC covers bytes 0~125
97	 * 1 = CRC covers bytes 0~116
98	 */
99
100	len = !(spd->info_size_crc & 0x80) ? 126 : 117;
101	csum16 = crc16(p, len);
102
103	crc_lsb = (char) (csum16 & 0xff);
104	crc_msb = (char) (csum16 >> 8);
105
106	if (spd->crc[0] == crc_lsb && spd->crc[1] == crc_msb) {
107		return 0;
108	} else {
109		printf("SPD checksum unexpected.\n"
110			"Checksum lsb in SPD = %02X, computed SPD = %02X\n"
111			"Checksum msb in SPD = %02X, computed SPD = %02X\n",
112			spd->crc[0], crc_lsb, spd->crc[1], crc_msb);
113		return 1;
114	}
115}
116
117unsigned int ddr4_spd_check(const struct ddr4_spd_eeprom_s *spd)
118{
119	char *p = (char *)spd;
120	int csum16;
121	int len;
122	char crc_lsb;	/* byte 126 */
123	char crc_msb;	/* byte 127 */
124
125	len = 126;
126	csum16 = crc16(p, len);
127
128	crc_lsb = (char) (csum16 & 0xff);
129	crc_msb = (char) (csum16 >> 8);
130
131	if (spd->crc[0] != crc_lsb || spd->crc[1] != crc_msb) {
132		printf("SPD checksum unexpected.\n"
133			"Checksum lsb in SPD = %02X, computed SPD = %02X\n"
134			"Checksum msb in SPD = %02X, computed SPD = %02X\n",
135			spd->crc[0], crc_lsb, spd->crc[1], crc_msb);
136		return 1;
137	}
138
139	p = (char *)((ulong)spd + 128);
140	len = 126;
141	csum16 = crc16(p, len);
142
143	crc_lsb = (char) (csum16 & 0xff);
144	crc_msb = (char) (csum16 >> 8);
145
146	if (spd->mod_section.uc[126] != crc_lsb ||
147	    spd->mod_section.uc[127] != crc_msb) {
148		printf("SPD checksum unexpected.\n"
149			"Checksum lsb in SPD = %02X, computed SPD = %02X\n"
150			"Checksum msb in SPD = %02X, computed SPD = %02X\n",
151			spd->mod_section.uc[126],
152			crc_lsb, spd->mod_section.uc[127],
153			crc_msb);
154		return 1;
155	}
156
157	return 0;
158}
159