aboutsummaryrefslogtreecommitdiff
path: root/arch/blackfin/mach-common/head.S
blob: 76de5724c1e3a27ec2fd2d13a6a7ed0232e05e19 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
/*
 * Common Blackfin startup code
 *
 * Copyright 2004-2008 Analog Devices Inc.
 *
 * Licensed under the GPL-2 or later.
 */

#include <linux/linkage.h>
#include <linux/init.h>
#include <asm/blackfin.h>
#include <asm/thread_info.h>
#include <asm/trace.h>
#include <asm/asm-offsets.h>

__INIT

ENTRY(__init_clear_bss)
	r2 = r2 - r1;
	cc = r2 == 0;
	if cc jump .L_bss_done;
	r2 >>= 2;
	p1 = r1;
	p2 = r2;
	lsetup (1f, 1f) lc0 = p2;
1:	[p1++] = r0;
.L_bss_done:
	rts;
ENDPROC(__init_clear_bss)

ENTRY(__start)
	/* R0: argument of command line string, passed from uboot, save it */
	R7 = R0;

	/* Enable Cycle Counter and Nesting Of Interrupts */
#ifdef CONFIG_BFIN_SCRATCH_REG_CYCLES
	R0 = SYSCFG_SNEN;
#else
	R0 = SYSCFG_SNEN | SYSCFG_CCEN;
#endif
	SYSCFG = R0;

	/* Optimization register tricks: keep a base value in the
	 * reserved P registers so we use the load/store with an
	 * offset syntax.  R0 = [P5 + <constant>];
	 *   P5 - core MMR base
	 *   R6 - 0
	 */
	r6 = 0;
	p5.l = 0;
	p5.h = hi(COREMMR_BASE);

	/* Zero out registers required by Blackfin ABI */

	/* Disable circular buffers */
	L0 = r6;
	L1 = r6;
	L2 = r6;
	L3 = r6;

	/* Disable hardware loops in case we were started by 'go' */
	LC0 = r6;
	LC1 = r6;

	/*
	 * Clear ITEST_COMMAND and DTEST_COMMAND registers,
	 * Leaving these as non-zero can confuse the emulator
	 */
	[p5 + (DTEST_COMMAND - COREMMR_BASE)] = r6;
	[p5 + (ITEST_COMMAND - COREMMR_BASE)] = r6;
	CSYNC;

	trace_buffer_init(p0,r0);

	/* Turn off the icache */
	r1 = [p5 + (IMEM_CONTROL - COREMMR_BASE)];
	BITCLR (r1, ENICPLB_P);
	[p5 + (IMEM_CONTROL - COREMMR_BASE)] = r1;
	SSYNC;

	/* Turn off the dcache */
	r1 = [p5 + (DMEM_CONTROL - COREMMR_BASE)];
	BITCLR (r1, ENDCPLB_P);
	[p5 + (DMEM_CONTROL - COREMMR_BASE)] = r1;
	SSYNC;

	/* in case of double faults, save a few things */
	p0.l = _init_retx;
	p0.h = _init_retx;
	R0 = RETX;
	[P0] = R0;

#ifdef CONFIG_DEBUG_DOUBLEFAULT
	/* Only save these if we are storing them,
	 * This happens here, since L1 gets clobbered
	 * below
	 */
	GET_PDA(p0, r0);
	r5 = [p0 + PDA_DF_RETX];
	p1.l = _init_saved_retx;
	p1.h = _init_saved_retx;
	[p1] = r5;

	r5 = [p0 + PDA_DF_DCPLB];
	p1.l = _init_saved_dcplb_fault_addr;
	p1.h = _init_saved_dcplb_fault_addr;
	[p1] = r5;

	r5 = [p0 + PDA_DF_ICPLB];
	p1.l = _init_saved_icplb_fault_addr;
	p1.h = _init_saved_icplb_fault_addr;
	[p1] = r5;

	r5 = [p0 + PDA_DF_SEQSTAT];
	p1.l = _init_saved_seqstat;
	p1.h = _init_saved_seqstat;
	[p1] = r5;
#endif

	/* Initialize stack pointer */
	sp.l = _init_thread_union + THREAD_SIZE;
	sp.h = _init_thread_union + THREAD_SIZE;
	fp = sp;
	usp = sp;

#ifdef CONFIG_EARLY_PRINTK
	call _init_early_exception_vectors;
	r0 = (EVT_IVHW | EVT_IRPTEN | EVT_EVX | EVT_NMI | EVT_RST | EVT_EMU);
	sti r0;
#endif

	r0 = r6;
	/* Zero out all of the fun bss regions */
#if L1_DATA_A_LENGTH > 0
	r1.l = __sbss_l1;
	r1.h = __sbss_l1;
	r2.l = __ebss_l1;
	r2.h = __ebss_l1;
	call __init_clear_bss
#endif
#if L1_DATA_B_LENGTH > 0
	r1.l = __sbss_b_l1;
	r1.h = __sbss_b_l1;
	r2.l = __ebss_b_l1;
	r2.h = __ebss_b_l1;
	call __init_clear_bss
#endif
#if L2_LENGTH > 0
	r1.l = __sbss_l2;
	r1.h = __sbss_l2;
	r2.l = __ebss_l2;
	r2.h = __ebss_l2;
	call __init_clear_bss
#endif
	r1.l = ___bss_start;
	r1.h = ___bss_start;
	r2.l = ___bss_stop;
	r2.h = ___bss_stop;
	call __init_clear_bss

	/* Put The Code for PLL Programming and SDRAM Programming in L1 ISRAM */
	call _bfin_relocate_l1_mem;

#ifdef CONFIG_ROMKERNEL
	call _bfin_relocate_xip_data;
#endif

#ifdef CONFIG_BFIN_KERNEL_CLOCK
	/* Only use on-chip scratch space for stack when absolutely required
	 * to avoid Anomaly 05000227 ... we know the init_clocks() func only
	 * uses L1 text and stack space and no other memory region.
	 */
# define KERNEL_CLOCK_STACK (L1_SCRATCH_START + L1_SCRATCH_LENGTH - 12)
	sp.l = lo(KERNEL_CLOCK_STACK);
	sp.h = hi(KERNEL_CLOCK_STACK);
	call _init_clocks;
	sp = usp;	/* usp hasn't been touched, so restore from there */
#endif

	/* This section keeps the processor in supervisor mode
	 * during kernel boot.  Switches to user mode at end of boot.
	 * See page 3-9 of Hardware Reference manual for documentation.
	 */

	/* EVT15 = _real_start */

	p1.l = _real_start;
	p1.h = _real_start;
	[p5 + (EVT15 - COREMMR_BASE)] = p1;
	csync;

#ifdef CONFIG_EARLY_PRINTK
	r0 = (EVT_IVG15 | EVT_IVHW | EVT_IRPTEN | EVT_EVX | EVT_NMI | EVT_RST | EVT_EMU) (z);
#else
	r0 = EVT_IVG15 (z);
#endif
	sti r0;

	raise 15;
#ifdef CONFIG_EARLY_PRINTK
	p0.l = _early_trap;
	p0.h = _early_trap;
#else
	p0.l = .LWAIT_HERE;
	p0.h = .LWAIT_HERE;
#endif
	reti = p0;
#if ANOMALY_05000281
	nop; nop; nop;
#endif
	rti;

.LWAIT_HERE:
	jump .LWAIT_HERE;
ENDPROC(__start)

/* A little BF561 glue ... */
#ifndef WDOG_CTL
# define WDOG_CTL WDOGA_CTL
#endif

ENTRY(_real_start)
	/* Enable nested interrupts */
	[--sp] = reti;

	/* watchdog off for now */
	p0.l = lo(WDOG_CTL);
	p0.h = hi(WDOG_CTL);
	r0 = 0xAD6(z);
	w[p0] = r0;
	ssync;

	/* Pass the u-boot arguments to the global value command line */
	R0 = R7;
	call _cmdline_init;

	sp += -12 + 4; /* +4 is for reti loading above */
	call _init_pda
	sp += 12;
	jump.l _start_kernel;
ENDPROC(_real_start)

__FINIT