sbf_dram_init.S 3.2 KB

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  1. /* SPDX-License-Identifier: GPL-2.0+ */
  2. /*
  3. * Board-specific early ddr/sdram init.
  4. *
  5. * (C) Copyright 2017 Angelo Dureghello <angelo@sysam.it>
  6. */
  7. .equ PPMCR0, 0xfc04002d
  8. .equ MSCR_SDRAMC, 0xec094060
  9. .equ MISCCR2, 0xec09001a
  10. .equ DDR_RCR, 0xfc0b8180
  11. .equ DDR_PADCR, 0xfc0b81ac
  12. .equ DDR_CR00, 0xfc0b8000
  13. .equ DDR_CR06, 0xfc0b8018
  14. .equ DDR_CR09, 0xfc0b8024
  15. .equ DDR_CR40, 0xfc0b80a0
  16. .equ DDR_CR45, 0xfc0b80b4
  17. .equ DDR_CR56, 0xfc0b80e0
  18. .global sbf_dram_init
  19. .text
  20. sbf_dram_init:
  21. /* CD46 = DDR on */
  22. move.l #PPMCR0, %a1
  23. move.b #46, (%a1)
  24. /* stmark 2, max drive strength */
  25. move.l #MSCR_SDRAMC, %a1
  26. move.b #1, (%a1)
  27. /*
  28. * use cpu clock, seems more realiable
  29. *
  30. * DDR2 clock is serviced from DDR controller as input clock / 2
  31. * so, if clock comes from
  32. * vco, i.e. 480(vco) / 2, so ddr clock is 240 Mhz (measured)
  33. * cpu, i.e. 250(cpu) / 2, so ddr clock is 125 Mhz (measured)
  34. *
  35. * .
  36. * / \ DDR2 can't be clocked lower than 125Mhz
  37. * / ! \ DDR2 init must pass further i/dcache enable test
  38. * /_____\
  39. * WARNING
  40. */
  41. /* cpu / 2 = 125 Mhz for 480 Mhz pll */
  42. move.l #MISCCR2, %a1
  43. move.w #0xa01d, (%a1)
  44. /* DDR force sw reset settings */
  45. move.l #DDR_RCR, %a1
  46. move.l #0x00000000, (%a1)
  47. move.l #0x40000000, (%a1)
  48. /*
  49. * PAD_ODT_CS: for us seems both 1(75 ohm) and 2(150ohm) are good,
  50. * 500/700 mV are ok
  51. */
  52. move.l #DDR_PADCR, %a1
  53. move.l #0x01030203, (%a1) /* as freescale tower */
  54. move.l #DDR_CR00, %a1
  55. move.l #0x01010101, (%a1)+ /* 0x00 */
  56. move.l #0x00000101, (%a1)+ /* 0x04 */
  57. move.l #0x01010100, (%a1)+ /* 0x08 */
  58. move.l #0x01010000, (%a1)+ /* 0x0C */
  59. move.l #0x00010101, (%a1)+ /* 0x10 */
  60. move.l #DDR_CR06, %a1
  61. move.l #0x00010100, (%a1)+ /* 0x18 */
  62. move.l #0x00000001, (%a1)+ /* 0x1C */
  63. move.l #0x01000001, (%a1)+ /* 0x20 */
  64. move.l #0x00000100, (%a1)+ /* 0x24 */
  65. move.l #0x00010001, (%a1)+ /* 0x28 */
  66. move.l #0x00000200, (%a1)+ /* 0x2C */
  67. move.l #0x01000002, (%a1)+ /* 0x30 */
  68. move.l #0x00000000, (%a1)+ /* 0x34 */
  69. move.l #0x00000100, (%a1)+ /* 0x38 */
  70. move.l #0x02000100, (%a1)+ /* 0x3C */
  71. move.l #0x02000407, (%a1)+ /* 0x40 */
  72. move.l #0x02030007, (%a1)+ /* 0x44 */
  73. move.l #0x02000100, (%a1)+ /* 0x48 */
  74. move.l #0x0A030203, (%a1)+ /* 0x4C */
  75. move.l #0x00020708, (%a1)+ /* 0x50 */
  76. move.l #0x00050008, (%a1)+ /* 0x54 */
  77. move.l #0x04030002, (%a1)+ /* 0x58 */
  78. move.l #0x00000004, (%a1)+ /* 0x5C */
  79. move.l #0x020A0000, (%a1)+ /* 0x60 */
  80. move.l #0x0C00000E, (%a1)+ /* 0x64 */
  81. move.l #0x00002004, (%a1)+ /* 0x68 */
  82. move.l #0x00000000, (%a1)+ /* 0x6C */
  83. move.l #0x00100010, (%a1)+ /* 0x70 */
  84. move.l #0x00100010, (%a1)+ /* 0x74 */
  85. move.l #0x00000000, (%a1)+ /* 0x78 */
  86. move.l #0x07990000, (%a1)+ /* 0x7C */
  87. move.l #DDR_CR40, %a1
  88. move.l #0x00000000, (%a1)+ /* 0xA0 */
  89. move.l #0x00C80064, (%a1)+ /* 0xA4 */
  90. move.l #0x44520002, (%a1)+ /* 0xA8 */
  91. move.l #0x00C80023, (%a1)+ /* 0xAC */
  92. move.l #DDR_CR45, %a1
  93. move.l #0x0000C350, (%a1) /* 0xB4 */
  94. move.l #DDR_CR56, %a1
  95. move.l #0x04000000, (%a1)+ /* 0xE0 */
  96. move.l #0x03000304, (%a1)+ /* 0xE4 */
  97. move.l #0x40040000, (%a1)+ /* 0xE8 */
  98. move.l #0xC0004004, (%a1)+ /* 0xEC */
  99. move.l #0x0642C000, (%a1)+ /* 0xF0 */
  100. move.l #0x00000642, (%a1)+ /* 0xF4 */
  101. move.l #DDR_CR09, %a1
  102. tpf
  103. move.l #0x01000100, (%a1) /* 0x24 */
  104. move.l #0x2000, %d1
  105. bsr asm_delay
  106. rts