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reset.S @ 623

Last change on this file since 623 was 606, checked in by alain, 11 years ago
Supporting fixed format for cluster index in reset.S.
File size: 7.9 KB

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1	/*
2	* \file : reset.S
3	* \date : 01/12/2012
4	* \author: Cesar FUGUET & Manuel BOUYER & Alain Greiner
5	*
6	* This is a generic reset code for a generic multi-clusters / multi-processors
7	* TSAR architecture (up to 256 clusters / up to 4 processors per cluster).
8	*
9	* There is one XICU, one TTY, one DMA, and one memory bank per cluster.
10	*
11	* This preloader uses a stack segment allocated in cluster 0, defined
12	* by the seg_reset_stack_base and seg_reset_stack_size parameters in ldscript.
13	* - Processor 0 uses a larger stack: 64 Kbytes.
14	* - Other processors use a smaller stack: 512 bytes.
15	* => the seg_stack_size cannot be smaller than 0x90000 bytes (576 K).
16	* Those stacks can be used by both the preloader and the boot-loader code.
17	*
18	* The replicated XICU is used to awake the sleeping processors:
19	* xicu_paddr_base = ICU_PADDR_BASE + (cluster_xy << 32)
20	*
21	* It is intended to be used with various operating systems or nano kernels,
22	* including NetBSD, ALMOS, and GIET_VM.
23	*
24	* - Each processor initializes its Status Register (SR) to disable interrupts.
25	* - Each processor initializes its Count Register.
26	* - Each processor initialises its private XICU WTI mask register.
27	* - Each processor initializes its Stack Pointer.
28	* - Only processor 0 executes the reset_load_elf function to load into memory
29	* the system specific boot-loader stored on disk at BOOT_LOADER_LBA
30	* - All other processors wait in a low power consumption mode that the
31	* processor 0 wakes them using an IPI (Inter Processor Interruption)
32	*/
33
34	#include <defs.h>
35	#include <mips32_registers.h>
36
37	/* These define should be consistent with values defined in map.xml file */
38
39	.extern seg_reset_stack_base
40	.extern seg_reset_stack_size
41
42	.section .reset,"ax",@progbits
43
44	.extern dtb_addr
45	.extern reset_putc
46	.extern reset_getc
47	.extern reset_ioc_read
48	.extern reset_elf_loader
49	.extern memcpy
50	.extern reset_puts
51	.extern reset_putx
52	.extern reset_putd
53	.extern reset_ioc_init
54	.extern versionstr
55
56	.globl reset /* Makes reset an external symbol */
57	.ent reset
58
59	.align 2
60	.set noreorder
61
62	reset:
63	b _reset /* 0xbfc0000 */
64	nop /* 0xbfc0004 */
65
66	/* Addresses of the functions provided by this reset code */
67
68	.word RESET_VERSION /* 0xbfc0008 */
69	.word dtb_addr /* 0xbfc000c */
70	.word reset_putc /* 0xbfc0010 */
71	.word reset_getc /* 0xbfc0014 */
72	.word reset_ioc_read /* 0xbfc0018 */
73	.word reset_elf_loader /* 0xbfc001C */
74	.word memcpy /* 0xbfc0020 */
75	.word reset_puts /* 0xbfc0024 */
76	.word reset_putx /* 0xbfc0028 */
77	.word reset_putd /* 0xbfc002C */
78
79	_reset:
80
81	/* All processors Disable interruptions, keep STATUSbev enabled */
82
83	li k0, (1 << 22)
84	mtc0 k0, CP0_STATUS
85
86	/* All processors compute proc_id, lpid, cluster_xy */
87
88	mfc0 k0, CP0_EBASE
89	andi t0, k0, 0x3FF /* t0 <= proc_id (at most 1024 processors) */
90
91	move t3, t0
92
93	la k0, NB_PROCS /* k0 <= number of processors per cluster */
94	divu t3, k0
95	mfhi t1 /* t1 <= lpid = proc_id % NB_PROCS */
96	mflo t2 /* t2 <= cluster_xy = proc_id / NB_PROCS */
97
98	/* All processors initialise the count register in CP0 */
99
100	mtc0 zero, CP0_COUNT
101
102	/*
103	* All processors enable the WTI for XICU
104	* Each processor may have IRQ_PER_PROC irq outputs from the XICU
105	* In each cluster, the XICU base address depends on the cluster_xy
106	*/
107
108	la t3, ICU_PADDR_BASE /* t3 <= ICU base address */
109	move t4, t1 /* t4 <= local_id */
110	li t5, IRQ_PER_PROC /* t5 <= IRQ_PER_PROC */
111	multu t4, t5
112	mflo t6 /* t6 <= IRQ_PER_PROC * local_id */
113	sll t4, t6, 2 /* t4 <= OUT_INDEX = t6 * 4 */
114
115	li t5, (0xC << 7) /* t5 <= FUNC = XICU_MSK_WTI */
116	or t4, t4, t5 /* t4 <= FUNC \| INDEX \| 00 */
117	or t5, t3, t4 /* t5 <= &XICU[MSK_WTI][OUT_INDEX] */
118
119	/* All processors set WTI mask using the physical address extension */
120
121	li t4, 1
122	sllv t4, t4, t1 /* Set XICU[MSK_WTI][INDEX][local_id] */
123
124	mtc2 t2, CP2_PADDR_EXT /* set PADDR extension */
125	sw t4, 0(t5) /* XICU[MSK_WTI][INDEX] <= t4 */
126	mtc2 zero, CP2_PADDR_EXT /* reset PADDR extension */
127
128	/* All processors initializes stack pointer, depending on proc_id */
129
130	la k0, seg_reset_stack_base
131	li k1, 0x10000 /* k1 <= P0 stack size == 64 Kbytes */
132	addu sp, k0, k1 /* P0 stack from base to (base + 64K) */
133
134	li k1, 0x200 /* k1 <= Pi stack size == 512 bytes */
135	multu k1, t0
136	mflo k0 /* k0 <= 256 * proc_id */
137	addu sp, sp, k1
138	addu sp, sp, k0 /* Pi stacks from base + 64K + proc_id256 /
139
140	/*
141	* Only processor 0 in cluster 0 loads and executes the boot-loader
142	* We have:
143	* t0: global proc_id
144	* t1: local proc_id
145	* t2: cluster_xy
146	* t3: xicu physical base address in cluster 0
147	*/
148
149	bne zero, t0, _reset_wait
150	nop
151
152	/* Processor 0 displays version for this reset code */
153
154	la a0, versionstr
155	la k0, reset_puts
156	jalr k0
157	nop
158
159
160	#ifndef SOCLIB_IOC
161
162	/* Processor 0 Initialize the block device if required */
163
164	la k0, reset_ioc_init
165	jalr k0
166	nop
167
168	#endif
169
170	/*
171	* Processor 0 jumps to the reset_elf_loader routine
172	* Passing as argument the block number in which is loaded the .elf file
173	*/
174
175	la k0, reset_elf_loader
176	li a0, BOOT_LOADER_LBA
177	jalr k0
178	nop
179
180	/*
181	* Processor O jumps to the entry address defined in the .elf file,
182	* and returned by reset_elf_loader function.
183	* All function arguments are 0
184	*/
185
186	move a0, zero
187	move a1, zero
188	move a2, zero
189	move a3, zero
190	jr v0
191	nop
192
193	/*
194	* All processor (but processor 0) wait in low power mode
195	* until processor 0 wakes them using an IPI.
196	* We have:
197	* t0: global id
198	* t1: local id
199	* t2: cluster id
200	* t3: xicu physical base address in cluster 0
201	*/
202
203	_reset_wait:
204
205	sll t4, t1, 2 /* t4 <= local_id * 4 */
206	addu t5, t4, t3 /* t5 <= &XICU[WTI_REG][local_id] */
207
208	wait
209
210	/*
211	* All other processors, when exiting wait mode,
212	* read from XICU the address to jump.
213	* This address is the boot-loader entry address that has been
214	* written in the mailbox by the IPI sent by processor 0
215	*/
216
217	mtc2 t2, CP2_PADDR_EXT /* set PADDR extension */
218	lw k0, 0(t5) /* k0 <= XICU[WTI_REG][local_id] */
219	mtc2 zero, CP2_PADDR_EXT /* reset PADDR extension */
220
221	jr k0
222	nop
223
224	/* Exception entry point */
225
226	.org 0x0380
227	_excep:
228	mfc0 a0, CP0_STATUS /* first arg is status */
229	mfc0 a1, CP0_CAUSE /* second arg is cause */
230	mfc0 a2, CP0_EPC /* third argc is epc */
231	nop
232	j handle_except
233	nop
234
235	.end reset
236
237	.set reorder
238
239	/*
240	* vim: tabstop=4 : shiftwidth=4 : expandtab
241	*/

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