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/* Copyright 2000 AG Electronics Ltd. */
/* This code is distributed without warranty under the GPL v2 (see COPYING) */
/*
* The aim of this code is to bring the machine from power-on to the point
* where we can jump to the the main LinuxBIOS entry point hardwaremain()
* which is written in C.
*
* At power-on, we have no RAM, a memory-mapped I/O space, and we are executing
* out of ROM, generally at 0xfff00100.
*
* Before we jump to harwaremain() we want to do the following:
*
* - enable L1 I/D caches, otherwise performance will be slow
* - set up DBATs for the following regions:
* - RAM (generally 0x00000000 -> 0x7fffffff)
* - ROM (_ROMBASE -> _ROMBASE + ROM_SIZE)
* - I/O (generally 0xfc000000 -> 0xfdffffff)
* - the main purpose for setting up the DBATs is so the I/O region
* can be marked cache inhibited/write through
* - set up IBATs for RAM and ROM
*
*/
#include <ppc750.h>
#define BSP_IOREGION1 0x80000000
#define BSP_IOMASK1 BAT_BL_256M | BAT_VALID_SUPERVISOR | BAT_VALID_USER
#define BSP_IOREGION2 0xFD000000
#define BSP_IOMASK2 BAT_BL_64M | BAT_VALID_SUPERVISOR | BAT_VALID_USER
isync
/*
* Disable dcache and MMU, so we're in a known state
*/
li r0, 0
sync
mtspr HID0, r0
sync
mtmsr r0
isync
/*
* Invalidate D & I BATS
*/
mtibatu 0, r0
mtibatu 1, r0
mtibatu 2, r0
mtibatu 3, r0
isync
mtdbatu 0, r0
mtdbatu 1, r0
mtdbatu 2, r0
mtdbatu 3, r0
isync
/*
* Clear segment registers (LinuxBIOS doesn't use these)
*/
li r3, 15
1: mtsrin r3, r0
subic. r3, r3, 1
bge 1b
isync
/*
* Set up DBATs
*
* DBAT0 covers RAM (0 -> 0x0FFFFFFF) (256Mb)
* DBAT1 covers PCI memory and ROM (0xFD000000 -> 0xFFFFFFFF) (64Mb)
* DBAT2 covers PCI memory (0x80000000 -> 0x8FFFFFFF) (256Mb)
* DBAT3 is not used
*/
lis r2, 0@h
ori r3, r2, BAT_BL_256M | BAT_VALID_SUPERVISOR | BAT_VALID_USER
ori r2, r2, BAT_READ_WRITE | BAT_GUARDED
mtdbatu 0, r3
mtdbatl 0, r2
isync
lis r2, BSP_IOREGION2@h
ori r3, r2, BAT_BL_64M | BAT_VALID_SUPERVISOR | BAT_VALID_USER
ori r2, r2, BAT_CACHE_INHIBITED | BAT_GUARDED | BAT_READ_WRITE
mtdbatu 1, r3
mtdbatl 1, r2
isync
lis r2, BSP_IOREGION1@h
ori r3, r2, BAT_BL_256M | BAT_VALID_SUPERVISOR | BAT_VALID_USER
ori r2, r2, BAT_CACHE_INHIBITED | BAT_GUARDED | BAT_READ_WRITE
mtdbatu 2, r3
mtdbatl 2, r2
isync
/*
* IBATS
*
* IBAT0 covers RAM (0 -> 256Mb)
* IBAT1 covers ROM (_ROMBASE -> _ROMBASE+ROM_SIZE)
*/
lis r2, 0@h
ori r3, r2, BAT_BL_256M | BAT_VALID_SUPERVISOR | BAT_VALID_USER
ori r2, r2, BAT_READ_WRITE
mtibatu 0, r3
mtibatl 0, r2
isync
lis r2, _ROMBASE@h
#if ROM_SIZE > 1048576
ori r3, r2, BAT_BL_16M | BAT_VALID_SUPERVISOR | BAT_VALID_USER
#else
ori r3, r2, BAT_BL_1M | BAT_VALID_SUPERVISOR | BAT_VALID_USER
#endif
ori r2, r2, BAT_READ_ONLY
mtibatu 1, r3
mtibatl 1, r2
isync
/*
* Enable MMU
*/
mfmsr r2
ori r2, r2, MSR_DR | MSR_IR
mtmsr r2
isync
sync
/*
* Enable and invalidate the L1 icache
*/
mfspr r2, HID0
ori r2, r2, HID0_ICE | HID0_ICFI
isync
mtspr HID0, r2
/*
* Enable and invalidate the L1 dcache
*/
mfspr r2, HID0
ori r2, r2, HID0_DCE | HID0_DCFI
sync
mtspr HID0, r2
/*
* Initialize data cache blocks
* (assumes cache block size of 32 bytes)
*/
lis r1, DCACHE_RAM_BASE@h
ori r1, r1, DCACHE_RAM_BASE@l
li r3, (DCACHE_RAM_SIZE / 32)
mtctr r3
0: dcbz r0, r1
addi r1, r1, 32
bdnz 0b
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