1 /* 2 * Copyright (C) 2022-2023, 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 ******************************************************************************/ 21 uintptr_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 STM32MP_DDR_BASE; 29 } 30 31 mmio_write_32(STM32MP_DDR_BASE, saved_value); 32 33 return 0UL; 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 ******************************************************************************/ 44 uintptr_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 STM32MP_DDR_BASE; 53 } 54 } 55 56 return 0UL; 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 ******************************************************************************/ 68 uintptr_t stm32mp_ddr_test_addr_bus(size_t size) 69 { 70 size_t addressmask = size - 1U; 71 size_t offset; 72 size_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 + offset, DDR_PATTERN); 78 } 79 80 /* Check for address bits stuck high. */ 81 mmio_write_32(STM32MP_DDR_BASE + testoffset, DDR_ANTIPATTERN); 82 83 for (offset = sizeof(uint32_t); (offset & addressmask) != 0U; 84 offset <<= 1U) { 85 if (mmio_read_32(STM32MP_DDR_BASE + offset) != DDR_PATTERN) { 86 return STM32MP_DDR_BASE + offset; 87 } 88 } 89 90 mmio_write_32(STM32MP_DDR_BASE + testoffset, DDR_PATTERN); 91 92 /* Check for address bits stuck low or shorted. */ 93 for (testoffset = sizeof(uint32_t); (testoffset & addressmask) != 0U; 94 testoffset <<= 1U) { 95 mmio_write_32(STM32MP_DDR_BASE + testoffset, DDR_ANTIPATTERN); 96 97 if (mmio_read_32(STM32MP_DDR_BASE) != DDR_PATTERN) { 98 return STM32MP_DDR_BASE; 99 } 100 101 for (offset = sizeof(uint32_t); (offset & addressmask) != 0U; 102 offset <<= 1) { 103 if ((mmio_read_32(STM32MP_DDR_BASE + offset) != DDR_PATTERN) && 104 (offset != testoffset)) { 105 return STM32MP_DDR_BASE + offset; 106 } 107 } 108 109 mmio_write_32(STM32MP_DDR_BASE + testoffset, DDR_PATTERN); 110 } 111 112 return 0UL; 113 } 114 115 /******************************************************************************* 116 * This function checks the DDR size. It has to be run with Data Cache off. 117 * This test is run before data have been put in DDR, and is only done for 118 * cold boot. The DDR data can then be overwritten, and it is not useful to 119 * restore its content. 120 * Returns DDR computed size. 121 ******************************************************************************/ 122 size_t stm32mp_ddr_check_size(void) 123 { 124 size_t offset = sizeof(uint32_t); 125 126 mmio_write_32(STM32MP_DDR_BASE, DDR_PATTERN); 127 128 while (offset < STM32MP_DDR_MAX_SIZE) { 129 mmio_write_32(STM32MP_DDR_BASE + offset, DDR_ANTIPATTERN); 130 dsb(); 131 132 if (mmio_read_32(STM32MP_DDR_BASE) != DDR_PATTERN) { 133 break; 134 } 135 136 offset <<= 1U; 137 } 138 139 return offset; 140 } 141