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diff --git a/doc/README.korat b/doc/README.korat deleted file mode 100644 index e059f78..0000000 --- a/doc/README.korat +++ /dev/null @@ -1,64 +0,0 @@ -The Korat board has two NOR flashes, FLASH0 and FLASH1, which are connected to -chip select 0 and 1, respectively. FLASH0 contains 16 MiB, and is mapped to -addresses 0xFF000000 - 0xFFFFFFFF as U-Boot Flash Bank #2. FLASH1 contains -from 16 to 128 MiB, and is mapped to 0xF?000000 - 0xF7FFFFFF as U-Boot Flash -Bank #1 (with the starting address depending on the flash size detected at -runtime). The write-enable pin on FLASH0 is disabled, so the contents of FLASH0 -cannot be modified in the field. This also prevents FLASH0 from executing -commands to return chip information, so its configuration is hard-coded in -U-Boot. - -There are two versions of U-Boot for Korat: "permanent" and "upgradable". The -permanent U-Boot is pre-programmed at the top of FLASH0, e.g., at addresses -0xFFFA0000 - 0xFFFFFFFF for the current 384 KiB size. The upgradable U-Boot is -located 256 KiB from the top of FLASH1, e.g. at addresses 0xF7F6000 - 0xF7FC0000 -for the current 384 KiB size. FLASH1 addresses 0xF7FE0000 - 0xF7FF0000 are -used for the U-Boot environmental parameters, and addresses 0xF7FC0000 - -0xF7FDFFFF are used for the redundant copy of the parameters. These locations -are used by both versions of U-Boot. - -On booting, the permanent U-Boot in FLASH0 begins executing. After performing -minimal setup, it monitors the state of the board's Reset switch (GPIO47). If -the switch is sensed as open before a timeout period, then U-Boot branches to -address 0xF7FBFFFC. This causes the upgradable U-Boot to execute from the -beginning. If the switch remains closed thoughout the timeout period, the -permanent U-Boot activates the on-board buzzer until the switch is sensed as -opened. It then continues to execute without branching to FLASH1. The effect -of this is that normally the Korat board boots its upgradable U-Boot, but, if -this has been corrupted, the user can boot the permanent U-Boot, which can then -be used to erase and reload FLASH1 as needed. - -Note that it is not necessary for the permanent U-Boot to have all the latest -features, but only that it have sufficient functionality (working "tftp", -"erase", "cp.b", etc.) to repair FLASH1. Also, the permanent U-Boot makes no -assumptions about the size of FLASH1 or the size of the upgradable U-Boot: it is -sufficient that the upgradable U-Boot can be started by a branch to 0xF7FBFFFC. - -The build sequence: - - make korat_perm_config - make all - -builds the permanent U-Boot by selecting loader file "u-boot.lds" and defining -preprocessor symbol "CONFIG_KORAT_PERMANENT". The default build: - - make korat_config - make all - -creates the upgradable U-Boot by selecting loader file "u-boot-F7FC.lds" and -leaving preprocessor symbol "CONFIG_KORAT_PERMANENT" undefined. - -2008-02-22, Larry Johnson <lrj@acm.org> - - -The CompactFlash(R) controller on the Korat board provides a hi-speed USB -interface. This may be connected to either a dedicated port on the on-board -USB controller, or to a USB port on the PowerPC 440EPx processor. The U-Boot -environment variable "korat_usbcf" can be used to specify which of these two -USB host ports is used for CompactFlash. The valid setting for the variable are -the strings "pci" and "ppc". If the variable defined and set to "ppc", then the -PowerPC USB port is used. In all other cases the on-board USB controller is -used, but if "korat_usbcf" is defined but is set to a string other than the two -valid options, a warning is also issued. - -2009-01-28, Larry Johnson <lrj@acm.org> |