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README.nand-boot-ppc440

README.nand-boot-ppc440 2.0 KB
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  1. -----------------------------
    2. 

  2. NAND boot on PPC440 platforms
    3. 

  3. -----------------------------
    4. 

  4. 

  5. This document describes the U-Boot NAND boot feature as it
    6. 

  6. is implemented for the AMCC Sequoia (PPC440EPx) board.
    7. 

  7. 

  8. The PPC440EP(x)/GR(x) cpu's can boot directly from NAND FLASH,
    9. 

  9. completely without NOR FLASH. This can be done by using the NAND
    10. 

  10. boot feature of the 440 NAND flash controller (NDFC).
    11. 

  11. 

  12. Here a short description of the different boot stages:
    13. 

  13. 

  14. a) IPL (Initial Program Loader, integrated inside CPU)
    15. 

  15. ------------------------------------------------------
    16. 

  16. Will load first 4k from NAND (SPL) into cache and execute it from there.
    17. 

  17. 

  18. b) SPL (Secondary Program Loader)
    19. 

  19. ---------------------------------
    20. 

  20. Will load special U-Boot version (NUB) from NAND and execute it. This SPL
    21. 

  21. has to fit into 4kByte. It sets up the CPU and configures the SDRAM
    22. 

  22. controller and the NAND controller so that the special U-Boot image can be
    23. 

  23. loaded from NAND to SDRAM.
    24. 

  24. This special image is build in the directory "nand_spl".
    25. 

  25. 

  26. c) NUB (NAND U-Boot)
    27. 

  27. --------------------
    28. 

  28. This NAND U-Boot (NUB) is a special U-Boot version which can be started
    29. 

  29. from RAM. Therefore it mustn't (re-)configure the SDRAM controller.
    30. 

  30. 

  31. On 440EPx the SPL is copied to internal SRAM before the NAND controller
    32. 

  32. is set up. While still running from cache, I experienced problems accessing
    33. 

  33. the NAND controller.
    34. 

  34. 

  35. 

  36. Example: Build and install NAND boot image for Sequoia (440EPx):
    37. 

  37. 

  38. a) Configure for sequoia with NAND boot support:
    39. 

  39. # make sequoia_nand_config
    40. 

  40. 

  41. b) Build image(s)
    42. 

  42. # make
    43. 

  43. 

  44. This will generate the SPL image in the "nand_spl" directory:
    45. 

  45. nand_spl/u-boot-spl.bin
    46. 

  46. Also another image is created spanning a whole NAND block (16kBytes):
    47. 

  47. nand_spl/u-boot-spl-16k.bin
    48. 

  48. The main NAND U-Boot image is generated in the toplevel directory:
    49. 

  49. u-boot.bin
    50. 

  50. A combined image of u-boot-spl-16k.bin and u-boot.bin is also created:
    51. 

  51. u-boot-nand.bin
    52. 

  52. 

  53. This image should be programmed at offset 0 in the NAND flash:
    54. 

  54. 

  55. # tftp 100000 /tftpboot/sequoia/u-boot-nand.bin
    56. 

  56. # nand erase 0 60000
    57. 

  57. # nand write 100000 0 60000
    58. 

  58. 

  59. 

  60. September 07 2006, Stefan Roese <sr@denx.de>
    61.