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boot_entry.S @ 439

Last change on this file since 439 was 439, checked in by satin@…, 8 years ago
Introduice new distributed Makefile architecture. Remove deprecated sys/ directory
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1	/*
2	* boot_entry.S - TSAR bootloader entry point.
3	*
4	* Authors : Alain Greiner / Vu Son (2016)
5	*
6	* Copyright (c) UPMC Sorbonne Universites
7	*
8	* This file is part of ALMOS-MKH.
9	*
10	* ALMOS-MKH is free software; you can redistribute it and/or modify it
11	* under the terms of the GNU General Public License as published by
12	* the Free Software Foundation; version 2.0 of the License.
13	*
14	* ALMOS-MKH is distributed in the hope that it will be useful, but
15	* WITHOUT ANY WARRANTY; without even the implied warranty of
16	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17	* General Public License for more details.
18	*
19	* You should have received a copy of the GNU General Public License
20	* along with ALMOS-MKH; if not, write to the Free Software Foundation,
21	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
22	*/
23
24	/**********************************************************************************************
25	* This file contains the entry point of the ALMOS-MK boot-loader for TSAR architecture. *
26	* It supports a generic multi-clusters / multi-processors architecture *
27	* *
28	* - The number of clusters is defined by the (X_SIZE, Y_SIZE) parameters in the *
29	* hard_config.h file (up to 256 clusters). *
30	* - The number of processors per cluster is defined by the NB_PROCS_MAX parameter in the *
31	* hard_config.h file (up to 4 processors per cluster). *
32	* *
33	* This assembly code is executed by all cores. It has 2 versions (in order to see if the *
34	* contention created by the ARCHINFO core descriptor table scanning loops is acceptable): *
35	* with or without the assumption that the core hardware identifier gid has a fixed format: *
36	* *
37	* - Version with fixed format: gid == (((x << Y_WIDTH) + y) << PADDR_WIDTH) + lid *
38	* It does 3 things: *
39	* + It initializes the stack pointer depending on the lid extracted from the gid, *
40	* using the BOOT_STACK_BASE and BOOT_STACK_SIZE parameters defined in the *
41	* 'boot_config.h' file, *
42	* + It changes the value of the address extension registers using the cxy extracted *
43	* from the gid, *
44	* + It jumps to the boot_loader() function defined in the 'boot.c' file and passes 2 *
45	* arguments which are the cxy and lid of each core to this function. *
46	* *
47	* - Version without fixed format *
48	* It has to perform an additional step in order to extract the (cxy,lid) values from the *
49	* arch_info.bin structure that has been loaded in the cluster (0,0) memory by the bscpu. *
50	* + Each core other than the bscpu scans the core descriptor table in the arch_info.bin *
51	* structure to make an associative search on the (gid), and get the (cxy,lid). *
52	* + It initializes the stack pointer depending on the lid, using the BOOT_STACK_BASE *
53	* and BOOT_STACK_SIZE parameters defined in the 'boot_config.h' file, *
54	* + It changes the value of the address extension registers using cxy obtained *
55	* previously, *
56	* + It jumps to the boot_loader() function defined in the 'boot.c' file and passes 2 *
57	* arguments which are the cxy and lid of each core to this function. *
58	*********************************************************************************************/
59
60	#include "mips32_registers.h"
61	#include "hard_config.h"
62	#include "boot_config.h"
63
64	.section .text, "ax", @progbits
65
66	.globl boot_entry
67	.ent boot_entry
68
69	.align 2
70	.set noreorder
71
72	boot_entry:
73
74	#if USE_FIXED_FORMAT
75
76	/*************
77	* VERSION 1 *
78	*************/
79
80	/*
81	* Get (cxy, lid) values from gid contained in coprocessor0 register.
82	*/
83
84	mfc0 k0, CP0_PROCID
85	andi k0, k0, 0xFFF /* k0 <= gid */
86	andi t1, k0, ((1 << P_WIDTH) - 1) /* t1 <= lid */
87	srl t2, k0, P_WIDTH /* t2 <= cxy */
88
89	/* Initialize stack pointer from previously retrieved lid value */
90
91	la t0, BOOT_STACK_BASE /* t0 <= BOOT_STACK_BASE */
92	li k1, BOOT_STACK_SIZE /* k1 <= BOOT_STACK_SIZE */
93	multu k1, t1
94	mflo k0 /* k0 <= BOOT_STACK_SIZE * lid */
95	subu sp, t0, k0 /* P[cxy,lid] stack top initialized */
96
97	/* Switch to local DSPACE by changing the value of the address extension registers */
98
99	mtc2 t2, CP2_DATA_PADDR_EXT
100
101	/* Jump to boot_loader() function after passing 2 arguments in the registers */
102
103	or a0, zero, t1 /* a0 <= lid */
104	or a1, zero, t2 /* a1 <= cxy */
105	la ra, boot_loader
106	jr ra
107	nop
108
109	#else
110
111	/*************
112	* VERSION 2 *
113	*************/
114
115	/* Test if this is bscpu */
116
117	mfc0 k0, CP0_PROCID
118	andi k0, k0, 0xFFF /* k0 <= gid */
119
120	li t1, BOOT_CORE_GID /* t1 <= bscpu gid */
121	or t3, zero, zero /* t3 <= bscpu lid = 0 */
122	beq k0, t1, bscpu_exit /* if bscpu, skip scanning core tbl */
123	li t4, BOOT_CORE_CXY /* t4 <= bscpu cxy */
124
125	/* Get base address of the core descriptor table in 'arch_info.bin' file */
126
127	la t0, ARCHINFO_BASE /* t0 <= ARCHINFO_BASE */
128	li t1, 0x80 /* t1 <= ARCHINFO_HEADER_SIZE */
129	addu t2, t0, t1 /* t2 <= ARCHINFO_CORE_BASE */
130
131	/* scan the core descriptor table if this is not bscpu. TODO If not found? */
132
133	li t3, 0x8 /* t3 <= ARCHINFO_CORE_SIZE */
134
135	scanning_core_table:
136	lw t1, 0(t2) /* t1 <= archinfo_core.gid */
137	bne t1, k0, scanning_core_table /* if (t1 != k0) => loop */
138	addu t2, t2, t3 /* t2 <= @ next archinfo_core */
139
140	/* Get (cxy, lid) values from the found core descriptor */
141
142	lw t3, -8(t2) /* t3 <= lid */
143	lw t4, -4(t2) /* t4 <= cxy */
144
145	/* Initialize stack pointer from previously retrieved lid value */
146
147	bscpu_exit:
148	la t0, BOOT_STACK_BASE /* t0 <= BOOT_STACK_BASE */
149	li k1, BOOT_STACK_SIZE /* k1 <= BOOT_STACK_SIZE */
150	multu k1, t3
151	mflo k0 /* k0 <= BOOT_STACK_SIZE * lid */
152	subu sp, t0, k0 /* P[cxy,lid] stack top initialized */
153
154	/* Switch to local DSPACE by changing the value of the address extension registers */
155
156	mtc2 t4, CP2_DATA_PADDR_EXT
157
158	/* Jumping to boot_loader() function after passing 2 arguments in registers */
159
160	or a0, zero, t3 /* a0 <= lid */
161	or a1, zero, t4 /* a1 <= cxy */
162	la ra, boot_loader
163	jr ra
164	nop
165
166	#endif
167
168	.end boot_entry
169
170	.set reorder

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