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gemini_prom.S

gemini_prom.S 2.2 KB
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  1. /*
    2. 

  2.  *  Not really prom support code (yet), but sort of anti-prom code.  The current
    3. 

  3.  *  bootloader does a number of things it shouldn't and doesn't do things that it
    4. 

  4.  *  should.  The stuff in here is mainly a hodge-podge collection of setup code
    5. 

  5.  *  to get the board up and running.
    6. 

  6.  *    ---Dan
    7. 

  7.  */
    8. 

  8. 

  9. #include <asm/reg.h>
    10. 

  10. #include <asm/page.h>
    11. 

  11. #include <platforms/gemini.h>
    12. 

  12. #include <asm/ppc_asm.h>
    13. 

  13. 

  14. /*
    15. 

  15.  *  On 750's the MMU is on when Linux is booted, so we need to clear out the
    16. 

  16.  *  bootloader's BAT settings, make sure we're in supervisor state (gotcha!),
    17. 

  17.  *  and turn off the MMU.
    18. 

  18.  *
    19. 

  19.  */
    20. 

  20. 

  21. _GLOBAL(gemini_prom_init)
    22. 

  22. #ifdef CONFIG_SMP
    23. 

  23. 	/* Since the MMU's on, get stuff in rom space that we'll need */
    24. 

  24. 	lis	r4,GEMINI_CPUSTAT@h
    25. 

  25. 	ori	r4,r4,GEMINI_CPUSTAT@l
    26. 

  26. 	lbz	r5,0(r4)
    27. 

  27. 	andi.	r5,r5,3
    28. 

  28. 	mr	r24,r5		/* cpu # used later on */
    29. 

  29. #endif
    30. 

  30. 	mfmsr	r4
    31. 

  31. 	li	r3,MSR_PR	/* ensure supervisor! */
    32. 

  32. 	ori	r3,r3,MSR_IR|MSR_DR
    33. 

  33. 	andc	r4,r4,r3
    34. 

  34. 	mtmsr	r4
    35. 

  35. 	isync
    36. 

  36. #if 0
    37. 

  37. 	/* zero out the bats now that the MMU is off */
    38. 

  38. prom_no_mmu:	
    39. 

  39. 	li	r3,0
    40. 

  40.         mtspr   SPRN_IBAT0U,r3
    41. 

  41.         mtspr   SPRN_IBAT0L,r3
    42. 

  42.         mtspr   SPRN_IBAT1U,r3
    43. 

  43.         mtspr   SPRN_IBAT1L,r3
    44. 

  44.         mtspr   SPRN_IBAT2U,r3
    45. 

  45.         mtspr   SPRN_IBAT2L,r3
    46. 

  46.         mtspr   SPRN_IBAT3U,r3
    47. 

  47.         mtspr   SPRN_IBAT3L,r3
    48. 

  48. 

  49.         mtspr   SPRN_DBAT0U,r3
    50. 

  50.         mtspr   SPRN_DBAT0L,r3
    51. 

  51.         mtspr   SPRN_DBAT1U,r3
    52. 

  52.         mtspr   SPRN_DBAT1L,r3
    53. 

  53.         mtspr   SPRN_DBAT2U,r3
    54. 

  54. 	mtspr   SPRN_DBAT2L,r3
    55. 

  55.         mtspr   SPRN_DBAT3U,r3
    56. 

  56.         mtspr   SPRN_DBAT3L,r3
    57. 

  57. #endif
    58. 

  58. 

  59. 	/* the bootloader (as far as I'm currently aware) doesn't mess with page
    60. 

  60. 	   tables, but since we're already here, might as well zap these, too */
    61. 

  61. 	li	r4,0
    62. 

  62. 	mtspr	SPRN_SDR1,r4
    63. 

  63. 

  64. 	li	r4,16
    65. 

  65. 	mtctr	r4
    66. 

  66. 	li	r3,0
    67. 

  67. 	li	r4,0
    68. 

  68. 3:	mtsrin	r3,r4
    69. 

  69. 	addi	r3,r3,1
    70. 

  70. 	bdnz	3b
    71. 

  71. 

  72. #ifdef CONFIG_SMP
    73. 

  73. 	/* The 750 book (and Mot/IBM support) says that this will "assist" snooping
    74. 

  74. 	   when in SMP.  Not sure yet whether this should stay or leave... */
    75. 

  75. 	mfspr	r4,SPRN_HID0
    76. 

  76. 	ori	r4,r4,HID0_ABE
    77. 

  77. 	mtspr	SPRN_HID0,r4
    78. 

  78. 	sync
    79. 

  79. #endif /* CONFIG_SMP */
    80. 

  80. 	blr
    81. 

  81. 

  82. /*  apparently, SMon doesn't pay attention to HID0[SRST].  Disable the MMU and
    83. 

  83.     branch to 0xfff00100 */
    84. 

  84. _GLOBAL(_gemini_reboot)
    85. 

  85. 	lis	r5,GEMINI_BOOT_INIT@h
    86. 

  86. 	ori	r5,r5,GEMINI_BOOT_INIT@l
    87. 

  87. 	li	r6,MSR_IP
    88. 

  88. 	mtspr	SPRN_SRR0,r5
    89. 

  89. 	mtspr	SPRN_SRR1,r6
    90. 

  90. 	rfi
    91.