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Diffstat (limited to 'board/walnut405/init.S')
| -rw-r--r-- | board/walnut405/init.S | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/board/walnut405/init.S b/board/walnut405/init.S new file mode 100644 index 0000000..d141707 --- /dev/null +++ b/board/walnut405/init.S @@ -0,0 +1,99 @@ +/*------------------------------------------------------------------------------+ */ +/* */ +/* This source code has been made available to you by IBM on an AS-IS */ +/* basis. Anyone receiving this source is licensed under IBM */ +/* copyrights to use it in any way he or she deems fit, including */ +/* copying it, modifying it, compiling it, and redistributing it either */ +/* with or without modifications. No license under IBM patents or */ +/* patent applications is to be implied by the copyright license. */ +/* */ +/* Any user of this software should understand that IBM cannot provide */ +/* technical support for this software and will not be responsible for */ +/* any consequences resulting from the use of this software. */ +/* */ +/* Any person who transfers this source code or any derivative work */ +/* must include the IBM copyright notice, this paragraph, and the */ +/* preceding two paragraphs in the transferred software. */ +/* */ +/* COPYRIGHT I B M CORPORATION 1995 */ +/* LICENSED MATERIAL - PROGRAM PROPERTY OF I B M */ +/*------------------------------------------------------------------------------- */ + +/*----------------------------------------------------------------------------- */ +/* Function: ext_bus_cntlr_init */ +/* Description: Initializes the External Bus Controller for the external */ +/* peripherals. IMPORTANT: For pass1 this code must run from */ +/* cache since you can not reliably change a peripheral banks */ +/* timing register (pbxap) while running code from that bank. */ +/* For ex., since we are running from ROM on bank 0, we can NOT */ +/* execute the code that modifies bank 0 timings from ROM, so */ +/* we run it from cache. */ +/* Bank 0 - Flash and SRAM */ +/* Bank 1 - NVRAM/RTC */ +/* Bank 2 - Keyboard/Mouse controller */ +/* Bank 3 - IR controller */ +/* Bank 4 - not used */ +/* Bank 5 - not used */ +/* Bank 6 - not used */ +/* Bank 7 - FPGA registers */ +/*----------------------------------------------------------------------------- */ +#include <ppc4xx.h> + +#include <ppc_asm.tmpl> +#include <ppc_defs.h> + +#include <asm/cache.h> +#include <asm/mmu.h> + + + .globl ext_bus_cntlr_init +ext_bus_cntlr_init: + mflr r4 /* save link register */ + bl ..getAddr +..getAddr: + mflr r3 /* get address of ..getAddr */ + mtlr r4 /* restore link register */ + addi r4,0,14 /* set ctr to 10; used to prefetch */ + mtctr r4 /* 10 cache lines to fit this function */ + /* in cache (gives us 8x10=80 instrctns) */ +..ebcloop: + icbt r0,r3 /* prefetch cache line for addr in r3 */ + addi r3,r3,32 /* move to next cache line */ + bdnz ..ebcloop /* continue for 10 cache lines */ + + /*------------------------------------------------------------------- */ + /* Delay to ensure all accesses to ROM are complete before changing */ + /* bank 0 timings. 200usec should be enough. */ + /* 200,000,000 (cycles/sec) X .000200 (sec) = 0x9C40 cycles */ + /*------------------------------------------------------------------- */ + addis r3,0,0x0 + ori r3,r3,0xA000 /* ensure 200usec have passed since reset */ + mtctr r3 +..spinlp: + bdnz ..spinlp /* spin loop */ + + /*----------------------------------------------------------------------- */ + /* Memory Bank 0 (Flash and SRAM) initialization */ + /*----------------------------------------------------------------------- */ + addi r4,0,pb0ap + mtdcr ebccfga,r4 + addis r4,0,0x9B01 + ori r4,r4,0x5480 + mtdcr ebccfgd,r4 + + addi r4,0,pb0cr + mtdcr ebccfga,r4 + addis r4,0,0xFFF1 /* BAS=0xFFF,BS=0x0(1MB),BU=0x3(R/W), */ + ori r4,r4,0x8000 /* BW=0x0( 8 bits) */ + mtdcr ebccfgd,r4 + + blr + + +/*----------------------------------------------------------------------------- */ +/* Function: sdram_init */ +/* Description: Dummy implementation here - done in C later */ +/*----------------------------------------------------------------------------- */ + .globl sdram_init +sdram_init: + blr |