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reset.S @ 656

Last change on this file since 656 was 653, checked in by cfuguet, 11 years ago

Introducing a RAMDISK driver in the preloader.

When using RAMDISK, execute the make command with the flags
SOCLIB=1 and RAMDISK=1. The RDK_PADDR_BASE variable must
also be set on the conf/<platform>/defs_platform.h

These modifications are backward compatibles. Therefore,
when no using RAMDISK, none modifications applied on the
platform configuration file.

File size: 8.0 KB

Line
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	preloader_vector:
69	.word RESET_VERSION /* 0xbfc0008 */
70	.word dtb_addr /* 0xbfc000c */
71	.word reset_putc /* 0xbfc0010 */
72	.word reset_getc /* 0xbfc0014 */
73	.word reset_ioc_read /* 0xbfc0018 */
74	.word reset_elf_loader /* 0xbfc001C */
75	.word memcpy /* 0xbfc0020 */
76	.word reset_puts /* 0xbfc0024 */
77	.word reset_putx /* 0xbfc0028 */
78	.word reset_putd /* 0xbfc002C */
79
80	_reset:
81
82	/* All processors Disable interruptions, keep STATUSbev enabled */
83
84	li k0, (1 << 22)
85	mtc0 k0, CP0_STATUS
86
87	/* All processors compute proc_id, lpid, cluster_xy */
88
89	mfc0 k0, CP0_EBASE
90	andi t0, k0, 0x3FF /* t0 <= proc_id (at most 1024 processors) */
91
92	move t3, t0
93
94	la k0, NB_PROCS /* k0 <= number of processors per cluster */
95	divu t3, k0
96	mfhi t1 /* t1 <= lpid = proc_id % NB_PROCS */
97	mflo t2 /* t2 <= cluster_xy = proc_id / NB_PROCS */
98
99	/* All processors initialise the count register in CP0 */
100
101	mtc0 zero, CP0_COUNT
102
103	/*
104	* All processors enable the WTI for XICU
105	* Each processor may have IRQ_PER_PROC irq outputs from the XICU
106	* In each cluster, the XICU base address depends on the cluster_xy
107	*/
108
109	la t3, ICU_PADDR_BASE /* t3 <= ICU base address */
110	move t4, t1 /* t4 <= local_id */
111	li t5, IRQ_PER_PROC /* t5 <= IRQ_PER_PROC */
112	multu t4, t5
113	mflo t6 /* t6 <= IRQ_PER_PROC * local_id */
114	sll t4, t6, 2 /* t4 <= OUT_INDEX = t6 * 4 */
115
116	li t5, (0xC << 7) /* t5 <= FUNC = XICU_MSK_WTI */
117	or t4, t4, t5 /* t4 <= FUNC \| INDEX \| 00 */
118	or t5, t3, t4 /* t5 <= &XICU[MSK_WTI][OUT_INDEX] */
119
120	/* All processors set WTI mask using the physical address extension */
121
122	li t4, 1
123	sllv t4, t4, t1 /* Set XICU[MSK_WTI][INDEX][local_id] */
124
125	mtc2 t2, CP2_PADDR_EXT /* set PADDR extension */
126	sw t4, 0(t5) /* XICU[MSK_WTI][INDEX] <= t4 */
127	mtc2 zero, CP2_PADDR_EXT /* reset PADDR extension */
128
129	/* All processors initializes stack pointer, depending on proc_id */
130
131	la k0, seg_reset_stack_base
132	li k1, 0x10000 /* k1 <= P0 stack size == 64 Kbytes */
133	addu sp, k0, k1 /* P0 stack from base to (base + 64K) */
134
135	li k1, 0x200 /* k1 <= Pi stack size == 512 bytes */
136	multu k1, t0
137	mflo k0 /* k0 <= 256 * proc_id */
138	addu sp, sp, k1
139	addu sp, sp, k0 /* Pi stacks from base + 64K + proc_id256 /
140
141	/*
142	* Only processor 0 in cluster 0 loads and executes the boot-loader
143	* We have:
144	* t0: global proc_id
145	* t1: local proc_id
146	* t2: cluster_xy
147	* t3: xicu physical base address in cluster 0
148	*/
149
150	bne zero, t0, _reset_wait
151	nop
152
153	/* Processor 0 displays version for this reset code */
154
155	la a0, versionstr
156	la k0, reset_puts
157	jalr k0
158	nop
159
160
161	#if USE_SPI
162
163	/* Processor 0 Initialize the SPI controller */
164
165	la k0, reset_ioc_init
166	jalr k0
167	nop
168
169	#endif
170
171	/*
172	* Processor 0 jumps to the reset_elf_loader routine
173	* Passing as argument the block number in which is loaded the .elf file
174	*/
175
176	la k0, reset_elf_loader
177	li a0, BOOT_LOADER_LBA
178	jalr k0
179	nop
180
181	/*
182	* Processor O jumps to the entry address defined in the .elf file,
183	* and returned by reset_elf_loader function.
184	* First argument is pointer to the preloader function vectors
185	* other function arguments are 0
186	*/
187
188	la a0, preloader_vector
189	move a1, zero
190	move a2, zero
191	move a3, zero
192	jr v0
193	nop
194
195	/*
196	* All processor (but processor 0) wait in low power mode
197	* until processor 0 wakes them using an IPI.
198	* We have:
199	* t0: global id
200	* t1: local id
201	* t2: cluster id
202	* t3: xicu physical base address in cluster 0
203	*/
204
205	_reset_wait:
206
207	sll t4, t1, 2 /* t4 <= local_id * 4 */
208	addu t5, t4, t3 /* t5 <= &XICU[WTI_REG][local_id] */
209
210	wait
211
212	/*
213	* All other processors, when exiting wait mode,
214	* read from XICU the address to jump.
215	* This address is the boot-loader entry address that has been
216	* written in the mailbox by the IPI sent by processor 0
217	*/
218
219	mtc2 t2, CP2_PADDR_EXT /* set PADDR extension */
220	lw k0, 0(t5) /* k0 <= XICU[WTI_REG][local_id] */
221	mtc2 zero, CP2_PADDR_EXT /* reset PADDR extension */
222
223	jr k0
224	nop
225
226	/* Exception entry point */
227
228	.org 0x0380
229	_excep:
230	mfc0 a0, CP0_STATUS /* first arg is status */
231	mfc0 a1, CP0_CAUSE /* second arg is cause */
232	mfc0 a2, CP0_EPC /* third argc is epc */
233	nop
234	j handle_except
235	nop
236
237	.end reset
238
239	.set reorder
240
241	/*
242	* vim: tabstop=4 : shiftwidth=4 : expandtab
243	*/

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