1 /*
2 * Copyright (C) 2022, STMicroelectronics - All Rights Reserved
3 *
4 * SPDX-License-Identifier: BSD-3-Clause
5 */
6
7 #include <common/debug.h>
8 #include <drivers/st/stm32mp_ddr_test.h>
9 #include <lib/mmio.h>
10
11 #include <platform_def.h>
12
13 #define DDR_PATTERN 0xAAAAAAAAU
14 #define DDR_ANTIPATTERN 0x55555555U
15
16 /*******************************************************************************
17 * This function tests a simple read/write access to the DDR.
18 * Note that the previous content is restored after test.
19 * Returns 0 if success, and address value else.
20 ******************************************************************************/
stm32mp_ddr_test_rw_access(void)21 uint32_t stm32mp_ddr_test_rw_access(void)
22 {
23 uint32_t saved_value = mmio_read_32(STM32MP_DDR_BASE);
24
25 mmio_write_32(STM32MP_DDR_BASE, DDR_PATTERN);
26
27 if (mmio_read_32(STM32MP_DDR_BASE) != DDR_PATTERN) {
28 return (uint32_t)STM32MP_DDR_BASE;
29 }
30
31 mmio_write_32(STM32MP_DDR_BASE, saved_value);
32
33 return 0U;
34 }
35
36 /*******************************************************************************
37 * This function tests the DDR data bus wiring.
38 * This is inspired from the Data Bus Test algorithm written by Michael Barr
39 * in "Programming Embedded Systems in C and C++" book.
40 * resources.oreilly.com/examples/9781565923546/blob/master/Chapter6/
41 * File: memtest.c - This source code belongs to Public Domain.
42 * Returns 0 if success, and address value else.
43 ******************************************************************************/
stm32mp_ddr_test_data_bus(void)44 uint32_t stm32mp_ddr_test_data_bus(void)
45 {
46 uint32_t pattern;
47
48 for (pattern = 1U; pattern != 0U; pattern <<= 1U) {
49 mmio_write_32(STM32MP_DDR_BASE, pattern);
50
51 if (mmio_read_32(STM32MP_DDR_BASE) != pattern) {
52 return (uint32_t)STM32MP_DDR_BASE;
53 }
54 }
55
56 return 0;
57 }
58
59 /*******************************************************************************
60 * This function tests the DDR address bus wiring.
61 * This is inspired from the Data Bus Test algorithm written by Michael Barr
62 * in "Programming Embedded Systems in C and C++" book.
63 * resources.oreilly.com/examples/9781565923546/blob/master/Chapter6/
64 * File: memtest.c - This source code belongs to Public Domain.
65 * size: size in bytes of the DDR memory device.
66 * Returns 0 if success, and address value else.
67 ******************************************************************************/
stm32mp_ddr_test_addr_bus(uint64_t size)68 uint32_t stm32mp_ddr_test_addr_bus(uint64_t size)
69 {
70 uint64_t addressmask = size - 1U;
71 uint64_t offset;
72 uint64_t testoffset = 0U;
73
74 /* Write the default pattern at each of the power-of-two offsets. */
75 for (offset = sizeof(uint32_t); (offset & addressmask) != 0U;
76 offset <<= 1U) {
77 mmio_write_32(STM32MP_DDR_BASE + (uint32_t)offset,
78 DDR_PATTERN);
79 }
80
81 /* Check for address bits stuck high. */
82 mmio_write_32(STM32MP_DDR_BASE + (uint32_t)testoffset,
83 DDR_ANTIPATTERN);
84
85 for (offset = sizeof(uint32_t); (offset & addressmask) != 0U;
86 offset <<= 1U) {
87 if (mmio_read_32(STM32MP_DDR_BASE + (uint32_t)offset) !=
88 DDR_PATTERN) {
89 return (uint32_t)(STM32MP_DDR_BASE + offset);
90 }
91 }
92
93 mmio_write_32(STM32MP_DDR_BASE + (uint32_t)testoffset, DDR_PATTERN);
94
95 /* Check for address bits stuck low or shorted. */
96 for (testoffset = sizeof(uint32_t); (testoffset & addressmask) != 0U;
97 testoffset <<= 1U) {
98 mmio_write_32(STM32MP_DDR_BASE + (uint32_t)testoffset,
99 DDR_ANTIPATTERN);
100
101 if (mmio_read_32(STM32MP_DDR_BASE) != DDR_PATTERN) {
102 return STM32MP_DDR_BASE;
103 }
104
105 for (offset = sizeof(uint32_t); (offset & addressmask) != 0U;
106 offset <<= 1) {
107 if ((mmio_read_32(STM32MP_DDR_BASE +
108 (uint32_t)offset) != DDR_PATTERN) &&
109 (offset != testoffset)) {
110 return (uint32_t)(STM32MP_DDR_BASE + offset);
111 }
112 }
113
114 mmio_write_32(STM32MP_DDR_BASE + (uint32_t)testoffset,
115 DDR_PATTERN);
116 }
117
118 return 0U;
119 }
120
121 /*******************************************************************************
122 * This function checks the DDR size. It has to be run with Data Cache off.
123 * This test is run before data have been put in DDR, and is only done for
124 * cold boot. The DDR data can then be overwritten, and it is not useful to
125 * restore its content.
126 * Returns DDR computed size.
127 ******************************************************************************/
stm32mp_ddr_check_size(void)128 uint32_t stm32mp_ddr_check_size(void)
129 {
130 uint32_t offset = sizeof(uint32_t);
131
132 mmio_write_32(STM32MP_DDR_BASE, DDR_PATTERN);
133
134 while (offset < STM32MP_DDR_MAX_SIZE) {
135 mmio_write_32(STM32MP_DDR_BASE + offset, DDR_ANTIPATTERN);
136 dsb();
137
138 if (mmio_read_32(STM32MP_DDR_BASE) != DDR_PATTERN) {
139 break;
140 }
141
142 offset <<= 1U;
143 }
144
145 INFO("Memory size = 0x%x (%u MB)\n", offset, offset / (1024U * 1024U));
146
147 return offset;
148 }
149