entry.s

BIOS Open Platform!

/**
 ** Standalone startup code for Linux PROM emulator.
 ** Copyright 1999 Pete A. Zaitcev
 ** This code is licensed under GNU General Public License.
 **/
/*
 * $Id: head.S,v 1.12 2002/07/23 05:47:09 zaitcev Exp $
 */

#define __ASSEMBLY__
#include "asi.h"
#include "pstate.h"
#include "lsu.h"

        .globl	entry, _entry

	.section ".text", "ax"
	.align	8
        .register %g2, #scratch
        .register %g3, #scratch
        .register %g6, #scratch
        .register %g7, #scratch

/*
 * Entry point
 * We start execution from here.
 */
_entry:
entry:
        ! Set up CPU state
        wrpr    %g0, PSTATE_PRIV, %pstate
        wr      %g0, 0, %fprs
        wrpr    %g0, 0x0, %tl

        ! Extract NWINDOWS from %ver
        rdpr    %ver, %g1
        and     %g1, 0xf, %g1
        dec     %g1
        wrpr    %g1, 0, %cleanwin
        wrpr    %g1, 0, %cansave
        wrpr    %g0, 0, %canrestore
        wrpr    %g0, 0, %otherwin
        wrpr    %g0, 0, %wstate

        ! Disable I/D MMUs and caches
        stxa    %g0, [%g0] ASI_LSU_CONTROL

        ! Get memory size from NVRAM
        setx    0x1fe02000074, %g2, %g5
        mov     0x30, %g2
        stba    %g2, [%g5] ASI_PHYS_BYPASS_EC_E
        add     %g5, 1, %g1
        stba    %g0, [%g1] ASI_PHYS_BYPASS_EC_E
        add     %g1, 2, %g1
	lduba	[%g1] ASI_PHYS_BYPASS_EC_E, %g4

        sll     %g4, 8, %g4
        inc     %g2
        stba    %g2, [%g5] ASI_PHYS_BYPASS_EC_E
	lduba	[%g1] ASI_PHYS_BYPASS_EC_E, %g3
        or      %g3, %g4, %g4

        sll     %g4, 8, %g4
        inc     %g2
        stba    %g2, [%g5] ASI_PHYS_BYPASS_EC_E
	lduba	[%g1] ASI_PHYS_BYPASS_EC_E, %g3
        or      %g3, %g4, %g4

        sll     %g4, 8, %g4
        inc     %g2
        stba    %g2, [%g5] ASI_PHYS_BYPASS_EC_E
	lduba	[%g1] ASI_PHYS_BYPASS_EC_E, %g3
        or      %g3, %g4, %g1
	! %g1 contains end of memory
        
        
        setx    _end, %g7, %g3
        set     0xffff, %g2
        add     %g3, %g2, %g3
        andn    %g3, %g2, %g3
        setx    _data, %g7, %g2
        sub     %g3, %g2, %g2
        sub	%g1, %g2, %g2			! %g2 = start of private memory
        mov     %g2, %l0

	! setup .data & .bss
        setx    _data, %g7, %g4
        sub     %g3, %g4, %g5
        srlx    %g5, 16, %g6			! %g6 = # of 64k .bss pages
	set	0xa0000000, %g3
	sllx	%g3, 32, %g3
	or	%g3, 0x76, %g3
	! valid, 64k, locked, cacheable(I/E/C), priv, writable
	set	48, %g7
1:	stxa	%g4, [%g7] ASI_DMMU		! vaddr = _data + N * 0x10000, ctx=0
	or	%g2, %g3, %g5
	! paddr = start_mem + N * 0x10000
	stxa	%g5, [%g0] ASI_DTLB_DATA_IN
	set	0x10000, %g5
	add	%g2, %g5, %g2
	add	%g4, %g5, %g4
	deccc	%g6
	bne	1b
	 nop

	! setup .rodata, also make .text readable
	setx	_data, %g7, %g5
	setx	_start, %g7, %g4
        sub     %g5, %g4, %g5
        srlx    %g5, 16, %g6			! %g6 = # of 64k .rodata pages
	set	48, %g7
	set	0x10000, %g5
1:      stxa	%g4, [%g7] ASI_DMMU		! vaddr = _rodata, ctx=0
	set	0xa0000000, %g3
	sllx	%g3, 32, %g3
	or	%g3, 0x74, %g3
	or	%g4, %g3, %g3
	! valid, 64k, locked, cacheable(I/E/C), priv
	! paddr = _rodata + N * 0x10000
	stxa	%g3, [%g0] ASI_DTLB_DATA_IN
	add	%g4, %g5, %g4
	deccc	%g6
	bne	1b
	 nop

	! setup VGA buffer
	setx	0x1ff004a0000, %g7, %g4
        mov     2, %g6
	set	48, %g7
	set	0x10000, %g5
1:      stxa	%g4, [%g7] ASI_DMMU		! vaddr = 0x1ff004a0000, ctx=0
	set	0xa0000000, %g3
	sllx	%g3, 32, %g3
	or	%g3, 0x76, %g3
	or	%g4, %g3, %g3
	! valid, 64k, locked, cacheable(I/E/C), priv, writable
	! paddr = 0x1ff004a0000
	stxa	%g3, [%g0] ASI_DTLB_DATA_IN
	add	%g4, %g5, %g4
	deccc	%g6
	bne	1b
	 nop

#if 0
	! setup 0-4M
	set	48, %g7
	stxa	%g0, [%g7] ASI_DMMU		! vaddr = 0, ctx=0
	set	0xe0000000, %g3
	sllx	%g3, 32, %g3
	or	%g3, 0x36, %g3
	! valid, 4M, cacheable(I/E/C), priv, writable
	! paddr = 0
	stxa	%g3, [%g0] ASI_DTLB_DATA_IN
#endif
	
	membar	#Sync

	setx	_start, %g7, %g4
	setx	_rodata, %g7, %g5
        sub     %g5, %g4, %g5
        srlx    %g5, 16, %g6			! %g6 = # of 64k .text pages
	set	48, %g7
1:      stxa	%g4, [%g7] ASI_IMMU		! vaddr = _start, ctx=0
	set	0xa0000000, %g3
	sllx	%g3, 32, %g3
	or	%g3, 0x74, %g3
	or	%g4, %g3, %g3
	! valid, 64k, locked, cacheable(I/E/C), priv
	! paddr = _start + N * 0x10000
	stxa	%g3, [%g0] ASI_ITLB_DATA_IN
	set	0x10000, %g5
	add	%g4, %g5, %g4
	deccc	%g6
	bne	1b
	 nop

#if 0
	! setup 0-4M
	stxa	%g0, [%g7] ASI_IMMU		! vaddr = 0, ctx=0
	set	0xe0000000, %g3
	sllx	%g3, 32, %g3
	or	%g3, 0x34, %g3
	! valid, 4M, cacheable(I/E/C), priv
	! paddr = 0
	stxa	%g3, [%g0] ASI_ITLB_DATA_IN
#endif

	flush	%g4

	mov	%g1, %g3

	set     8, %g2
	sta     %g0, [%g2] ASI_DMMU		! set primary ctx=0

	! Enable I/D MMUs and caches
	set	LSU_CONTROL_DM|LSU_CONTROL_IM|LSU_CONTROL_DC|LSU_CONTROL_IC, %g2
	stxa	%g2, [%g0] ASI_LSU_CONTROL

        /* Copy the DATA section from ROM. */
        setx	_data - 8, %o7, %o0             ! First address of DATA
        setx	_bss, %o7, %o1                  ! Last address of DATA
        ba	2f
         nop
1:
        ldxa    [%o0] ASI_PHYS_BYPASS_EC_E, %g1
        stx	%g1, [%o0]
2:
        subcc	%o0, %o1, %g0
        bl	1b
         add	%o0, 0x8, %o0

        /* Zero out our BSS section. */
        setx    _bss - 8, %o7, %o0              ! First address of BSS
        setx    _end, %o7, %o1                  ! Last address of BSS
        ba	2f
         nop
1:
        stx     %g0, [%o0]
2:
        subcc	%o0, %o1, %g0
        bl	1b
         add	%o0, 0x8, %o0

        setx    trap_table, %g2, %g1
        wrpr    %g1, %tba

        setx    qemu_mem_size, %g7, %g1
        stx     %g3, [%g1]
        
        setx    _data, %g7, %g1                 ! Store va->pa conversion factor
        sub     %g1, %l0, %g2
        setx    va_shift, %g7, %g1
        stx     %g2, [%g1]

        /* Finally, turn on traps so that we can call c-code. */
	wrpr    %g0, (PSTATE_PRIV|PSTATE_PEF|PSTATE_IE), %pstate

        /* Switch to our main context.
         * Main context is statically defined in C.
         */

        call    __switch_context_nosave
         nop

        /* We get here when the main context switches back to
         * the boot context.
         * Return to previous bootloader.
         */
        ret
         nop