/*
* start.S : RTEMS entry point
*
* Copyright (C) 1999 Eric Valette. valette@crf.canon.fr
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.org/license/LICENSE.
*
*/
#include <rtems/asm.h>
#include <rtems/score/cpu.h>
#include <rtems/powerpc/powerpc.h>
#include <libcpu/io.h>
#include <libcpu/bat.h>
#include <bspopts.h>
#define SYNC \
sync; \
isync
#define KERNELBASE 0x0
#define MONITOR_ENTER \
mfmsr r10 ; \
ori r10,r10,MSR_IP ; \
mtmsr r10 ; \
li r10,0x63 ; \
sc
.text
.globl __rtems_entry_point
.type __rtems_entry_point,@function
__rtems_entry_point:
#ifdef DEBUG_EARLY_START
MONITOR_ENTER
#endif
/*
* PREP
* This is jumped to on prep systems right after the kernel is relocated
* to its proper place in memory by the boot loader. The expected layout
* of the regs is:
* r3: ptr to residual data
* r4: initrd_start or if no initrd then 0
* r5: initrd_end - unused if r4 is 0
* r6: Start of command line string
* r7: End of command line string
*
* The Prep boot loader insure that the MMU is currently off...
*
*/
mr r31,r3 /* save parameters */
mr r30,r4
mr r29,r5
mr r28,r6
mr r27,r7
#ifdef __ALTIVEC__
/* enable altivec; gcc may use it! */
mfmsr r0
oris r0, r0, (1<<(31-16-6))
mtmsr r0
isync
/*
* set vscr and vrsave to known values
*/
li r0, 0
mtvrsave r0
vxor 0,0,0
mtvscr 0
#endif
/*
* Make sure we have nothing in BATS and TLB
*/
bl CPU_clear_bats_early
bl flush_tlbs
/*
* Use the first pair of BAT registers to map the 1st 256MB
* of RAM to KERNELBASE.
*/
lis r11,KERNELBASE@h
/* set up BAT registers for 604 */
ori r11,r11,0x1ffe
li r8,2 /* R/W access */
isync
mtspr DBAT0L,r8 /* N.B. 6xx (not 601) have valid */
mtspr DBAT0U,r11 /* bit in upper BAT register */
mtspr IBAT0L,r8
mtspr IBAT0U,r11
isync
/*
* we now have the 1st 256M of ram mapped with the bats. We are still
* running on the bootloader stack and cannot switch to an RTEMS allocated
* init stack before copying the residual data that may have been set just after
* rtems_end address. This bug has been experienced on MVME2304. Thank to
* Till Straumann <strauman@SLAC.Stanford.EDU> for hunting it and suggesting
* the appropriate code.
*/
enter_C_code:
bl MMUon
bl __eabi /* setup EABI and SYSV environment */
bl zero_bss
/*
* restore prep boot params
*/
mr r3,r31
mr r4,r30
mr r5,r29
mr r6,r28
mr r7,r27
bl save_boot_params
/*
* stack = &__rtems_end + 4096
*/
addis r9,r0, __stack-PPC_MINIMUM_STACK_FRAME_SIZE@ha
addi r9,r9, __stack-PPC_MINIMUM_STACK_FRAME_SIZE@l
/*
* align initial stack
* (we hope that the bootloader stack was 16-byte aligned
* or we haven't used altivec yet...)
*/
li r0, (CPU_STACK_ALIGNMENT-1)
andc r1, r9, r0
/*
* Tag TOS with a NULL (terminator for stack dump)
*/
li r0, 0
stw r0, 0(r1)
/*
* We are now in a environment that is totally independent from
* bootloader setup.
*/
/* pass result of 'save_boot_params' to 'boot_card' in R3 */
bl boot_card
bl _return_to_ppcbug
.globl MMUon
.type MMUon,@function
MMUon:
mfmsr r0
ori r0,r0, MSR_IP | MSR_RI | MSR_IR | MSR_DR | MSR_EE | MSR_FE0 | MSR_FE1 | MSR_FP
#if (PPC_HAS_FPU == 0)
xori r0, r0, MSR_EE | MSR_IP | MSR_FP
#else
xori r0, r0, MSR_EE | MSR_IP | MSR_FE0 | MSR_FE1
#endif
mflr r11
mtsrr0 r11
mtsrr1 r0
SYNC
rfi
.globl MMUoff
.type MMUoff,@function
MMUoff:
mfmsr r0
ori r0,r0,MSR_IR| MSR_DR | MSR_IP
mflr r11
xori r0,r0,MSR_IR|MSR_DR
mtsrr0 r11
mtsrr1 r0
SYNC
rfi
.globl _return_to_ppcbug
.type _return_to_ppcbug,@function
_return_to_ppcbug:
mflr r30
bl MMUoff
MONITOR_ENTER
bl MMUon
mtctr r30
bctr
flush_tlbs:
lis r20, 0x1000
1: addic. r20, r20, -0x1000
tlbie r20
bgt 1b
sync
blr
