Root/target/linux/generic/image/lzma-loader/src/start.S

1#include <asm/asm.h>
2#include <asm/regdef.h>
3
4#define KSEG0 0x80000000
5
6#define C0_CONFIG $16
7#define C0_TAGLO $28
8#define C0_TAGHI $29
9
10#define CONF1_DA_SHIFT 7 /* D$ associativity */
11#define CONF1_DA_MASK 0x00000380
12#define CONF1_DA_BASE 1
13#define CONF1_DL_SHIFT 10 /* D$ line size */
14#define CONF1_DL_MASK 0x00001c00
15#define CONF1_DL_BASE 2
16#define CONF1_DS_SHIFT 13 /* D$ sets/way */
17#define CONF1_DS_MASK 0x0000e000
18#define CONF1_DS_BASE 64
19#define CONF1_IA_SHIFT 16 /* I$ associativity */
20#define CONF1_IA_MASK 0x00070000
21#define CONF1_IA_BASE 1
22#define CONF1_IL_SHIFT 19 /* I$ line size */
23#define CONF1_IL_MASK 0x00380000
24#define CONF1_IL_BASE 2
25#define CONF1_IS_SHIFT 22 /* Instruction cache sets/way */
26#define CONF1_IS_MASK 0x01c00000
27#define CONF1_IS_BASE 64
28
29#define Index_Invalidate_I 0x00
30#define Index_Writeback_Inv_D 0x01
31
32LEAF(_start)
33    
34    .set mips32
35    .set noreorder
36
37    /* save argument registers */
38    move t4, a0
39    move t5, a1
40    move t6, a2
41    move t7, a3
42    
43    /* set up stack */
44    li sp, RAMSTART + RAMSIZE - 16
45
46#ifdef IMAGE_COPY
47    /* Copy decompressor code to the right place */
48    li t2, LOADADDR
49    add a0, t2, 0
50    la a1, code_start
51    la a2, code_stop
52$L1:
53    lw t0, 0(a1)
54    sw t0, 0(a0)
55    add a1, 4
56    add a0, 4
57    blt a1, a2, $L1
58    nop
59#endif
60
61    /* At this point we need to invalidate dcache and */
62    /* icache before jumping to new code */
63
641: /* Get cache sizes */
65    mfc0 s0,C0_CONFIG,1
66
67    li s1,CONF1_DL_MASK
68    and s1,s0
69    beq s1,zero,nodc
70    nop
71
72    srl s1,CONF1_DL_SHIFT
73    li t0,CONF1_DL_BASE
74    sll s1,t0,s1 /* s1 has D$ cache line size */
75
76    li s2,CONF1_DA_MASK
77    and s2,s0
78    srl s2,CONF1_DA_SHIFT
79    addiu s2,CONF1_DA_BASE /* s2 now has D$ associativity */
80
81    li t0,CONF1_DS_MASK
82    and t0,s0
83    srl t0,CONF1_DS_SHIFT
84    li s3,CONF1_DS_BASE
85    sll s3,s3,t0 /* s3 has D$ sets per way */
86
87    multu s2,s3 /* sets/way * associativity */
88    mflo t0 /* total cache lines */
89
90    multu s1,t0 /* D$ linesize * lines */
91    mflo s2 /* s2 is now D$ size in bytes */
92
93    /* Initilize the D$: */
94    mtc0 zero,C0_TAGLO
95    mtc0 zero,C0_TAGHI
96
97    li t0,KSEG0 /* Just an address for the first $ line */
98    addu t1,t0,s2 /* + size of cache == end */
99
1001: cache Index_Writeback_Inv_D,0(t0)
101    bne t0,t1,1b
102    addu t0,s1
103    
104nodc:
105    /* Now we get to do it all again for the I$ */
106    
107    move s3,zero /* just in case there is no icache */
108    move s4,zero
109
110    li t0,CONF1_IL_MASK
111    and t0,s0
112    beq t0,zero,noic
113    nop
114
115    srl t0,CONF1_IL_SHIFT
116    li s3,CONF1_IL_BASE
117    sll s3,t0 /* s3 has I$ cache line size */
118
119    li t0,CONF1_IA_MASK
120    and t0,s0
121    srl t0,CONF1_IA_SHIFT
122    addiu s4,t0,CONF1_IA_BASE /* s4 now has I$ associativity */
123
124    li t0,CONF1_IS_MASK
125    and t0,s0
126    srl t0,CONF1_IS_SHIFT
127    li s5,CONF1_IS_BASE
128    sll s5,t0 /* s5 has I$ sets per way */
129
130    multu s4,s5 /* sets/way * associativity */
131    mflo t0 /* s4 is now total cache lines */
132
133    multu s3,t0 /* I$ linesize * lines */
134    mflo s4 /* s4 is cache size in bytes */
135
136    /* Initilize the I$: */
137    mtc0 zero,C0_TAGLO
138    mtc0 zero,C0_TAGHI
139
140    li t0,KSEG0 /* Just an address for the first $ line */
141    addu t1,t0,s4 /* + size of cache == end */
142
1431: cache Index_Invalidate_I,0(t0)
144    bne t0,t1,1b
145    addu t0,s3
146noic:
147    /* jump to main */
148    move a0,s3 /* icache line size */
149    move a1,s4 /* icache size */
150    move a2,s1 /* dcache line size */
151#ifdef IMAGE_COPY
152    jal t2
153#else
154    jal entry
155#endif
156    move a3,s2 /* dcache size */
157
158    .set reorder
159END(_start)
160
161

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