sbf_dram_init.S 3.2 KB

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