OpenWrt – Rev 4

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/* Copyright 2005 Oleg I. Vdovikin (oleg@cs.msu.su)     */
/* cache manipulation adapted from Broadcom code        */
/* idea taken from original bunzip2 decompressor code   */
/* Copyright 2004 Manuel Novoa III (mjn3@codepoet.org)  */
/* Licensed under the linux kernel's version of the GPL.*/

#include <asm/asm.h>
#include <asm/regdef.h>

#define KSEG0           0x80000000

#define C0_CONFIG       $16
#define C0_TAGLO        $28
#define C0_TAGHI        $29

#define CONF1_DA_SHIFT  7                       /* D$ associativity */
#define CONF1_DA_MASK   0x00000380
#define CONF1_DA_BASE   1
#define CONF1_DL_SHIFT  10                      /* D$ line size */
#define CONF1_DL_MASK   0x00001c00
#define CONF1_DL_BASE   2
#define CONF1_DS_SHIFT  13                      /* D$ sets/way */
#define CONF1_DS_MASK   0x0000e000
#define CONF1_DS_BASE   64
#define CONF1_IA_SHIFT  16                      /* I$ associativity */
#define CONF1_IA_MASK   0x00070000
#define CONF1_IA_BASE   1
#define CONF1_IL_SHIFT  19                      /* I$ line size */
#define CONF1_IL_MASK   0x00380000
#define CONF1_IL_BASE   2
#define CONF1_IS_SHIFT  22                      /* Instruction cache sets/way */
#define CONF1_IS_MASK   0x01c00000
#define CONF1_IS_BASE   64

#define Index_Invalidate_I      0x00
#define Index_Writeback_Inv_D   0x01

        .text
        LEAF(startup)
        .set noreorder
        li      sp, BZ_STACK_START
        addi    sp, -48
        sw      a0, 16(sp)
        sw      a1, 20(sp)
        sw      a2, 24(sp)
        sw      a3, 28(sp)

        /* Copy decompressor code to the right place */
        li      t2, BZ_TEXT_START
        add     a0, t2, 0
        la      a1, code_start
        la      a2, code_stop
$L1:
        lw      t0, 0(a1)
        sw      t0, 0(a0)
        add     a1, 4
        add     a0, 4
        blt     a1, a2, $L1
        nop

        /* At this point we need to invalidate dcache and */
        /* icache before jumping to new code */

1:      /* Get cache sizes */
        .set    mips32
        mfc0    s0,C0_CONFIG,1
        .set    mips0

        li      s1,CONF1_DL_MASK
        and     s1,s0
        beq     s1,zero,nodc
        nop

        srl     s1,CONF1_DL_SHIFT
        li      t0,CONF1_DL_BASE
        sll     s1,t0,s1                /* s1 has D$ cache line size */

        li      s2,CONF1_DA_MASK
        and     s2,s0
        srl     s2,CONF1_DA_SHIFT
        addiu   s2,CONF1_DA_BASE        /* s2 now has D$ associativity */

        li      t0,CONF1_DS_MASK
        and     t0,s0
        srl     t0,CONF1_DS_SHIFT
        li      s3,CONF1_DS_BASE
        sll     s3,s3,t0                /* s3 has D$ sets per way */

        multu   s2,s3                   /* sets/way * associativity */
        mflo    t0                      /* total cache lines */

        multu   s1,t0                   /* D$ linesize * lines */
        mflo    s2                      /* s2 is now D$ size in bytes */

        /* Initilize the D$: */
        mtc0    zero,C0_TAGLO
        mtc0    zero,C0_TAGHI

        li      t0,KSEG0                /* Just an address for the first $ line */
        addu    t1,t0,s2                /*  + size of cache == end */

        .set    mips3
1:      cache   Index_Writeback_Inv_D,0(t0)
        .set    mips0
        bne     t0,t1,1b
        addu    t0,s1

nodc:
        /* Now we get to do it all again for the I$ */

        move    s3,zero                 /* just in case there is no icache */
        move    s4,zero

        li      t0,CONF1_IL_MASK
        and     t0,s0
        beq     t0,zero,noic
        nop

        srl     t0,CONF1_IL_SHIFT
        li      s3,CONF1_IL_BASE
        sll     s3,t0                   /* s3 has I$ cache line size */

        li      t0,CONF1_IA_MASK
        and     t0,s0
        srl     t0,CONF1_IA_SHIFT
        addiu   s4,t0,CONF1_IA_BASE     /* s4 now has I$ associativity */

        li      t0,CONF1_IS_MASK
        and     t0,s0
        srl     t0,CONF1_IS_SHIFT
        li      s5,CONF1_IS_BASE
        sll     s5,t0                   /* s5 has I$ sets per way */

        multu   s4,s5                   /* sets/way * associativity */
        mflo    t0                      /* s4 is now total cache lines */

        multu   s3,t0                   /* I$ linesize * lines */
        mflo    s4                      /* s4 is cache size in bytes */

        /* Initilize the I$: */
        mtc0    zero,C0_TAGLO
        mtc0    zero,C0_TAGHI

        li      t0,KSEG0                /* Just an address for the first $ line */
        addu    t1,t0,s4                /*  + size of cache == end */

        .set    mips3
1:      cache   Index_Invalidate_I,0(t0)
        .set    mips0
        bne     t0,t1,1b
        addu    t0,s3

noic:
        move    a0,s4                   /* icache size */
        move    a1,s3                   /* icache line size */
        move    a2,s2                   /* dcache size */
        jal     t2
        move    a3,s1                   /* dcache line size */

        .set reorder
        END(startup)