source: trunk/softs/tsar_boot/src/reset.S @ 777

Last change on this file since 777 was 758, checked in by cfuguet, 10 years ago

tsar_boot: improving configuration infrastructure

  • Using hard_config.h which respects the same sintax that the hard_config.h file of all TSAR platforms. This file can be then generated by the GIET-VM genmap tool or written manually.
  • All peripheral drivers have been moved to a drivers directory and they are compiled as a static library. This allows GCC to only include in the final .ELF the object files of used peripherals and not all of them.
  • Example hard_config.h and ldscripts have been introduced in the conf directory.
  • Improving comments in all files
File size: 7.3 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 for processor 0.
12 * The stack allocation is not performed for other processors as they do not
13 * need it during the preloader execution. Therefore, this allocation should be
14 * done by the loaded Operating System.
15 *
16 * The replicated XICU is used to awake the sleeping processors:
17 *      xicu_paddr_base = ICU_PADDR_BASE + (cluster_xy << 32)
18 *
19 * It is intended to be used with various operating systems or nano kernels,
20 * including NetBSD, Linux, ALMOS, and GIET_VM.
21 *
22 * - Each processor initializes its Status Register (SR) to disable interrupts.
23 * - Each processor initializes its Count Register.
24 * - Each processor initialises its private XICU WTI mask register.
25 * - Only processor 0 executes the reset_load_elf function to load into memory
26 *   the system specific boot-loader stored on disk at RESET_LOADER_LBA
27 * - All other processors wait in a low power consumption mode that the
28 *   processor 0 wakes them using an IPI (Inter Processor Interruption)
29 */
30
31    #include <defs.h>
32    #include <mips32_registers.h>
33
34    /* These define should be consistent with values defined in map.xml file  */
35
36    .section .reset,"ax",@progbits
37
38    .extern dtb_addr
39    .extern reset_putc
40    .extern reset_getc
41    .extern reset_ioc_read
42    .extern reset_elf_loader
43    .extern memcpy
44    .extern reset_puts
45    .extern reset_putx
46    .extern reset_putd
47    .extern reset_ioc_init
48    .extern versionstr
49
50    .globl  reset                    /* Makes reset an external symbol */
51    .ent    reset
52
53    .align  2
54    .set noreorder
55
56reset:
57    b       _reset                   /* 0xbfc0000 */
58    nop                              /* 0xbfc0004 */
59
60    /*  Addresses of the functions provided by this reset code */
61
62preloader_vector:
63    .word   RESET_VERSION            /* 0xbfc0008 */
64    .word   dtb_addr                 /* 0xbfc000c */
65    .word   reset_putc               /* 0xbfc0010 */
66    .word   reset_getc               /* 0xbfc0014 */
67    .word   reset_ioc_read           /* 0xbfc0018 */
68    .word   reset_elf_loader         /* 0xbfc001C */
69    .word   memcpy                   /* 0xbfc0020 */
70    .word   reset_puts               /* 0xbfc0024 */
71    .word   reset_putx               /* 0xbfc0028 */
72    .word   reset_putd               /* 0xbfc002C */
73
74_reset:
75
76    /* All processors Disable interruptions, keep STATUSbev enabled */
77
78    li      k0,     (1 << 22)
79    mtc0    k0,     CP0_STATUS
80
81    /* All processors compute pid, lpid, cluster_xy */
82
83    mfc0    k0,     CP0_EBASE
84    andi    t0,     k0,     0x3FF    /* t0 <= pid (at most 1024 procs)      */
85
86    move    t3,     t0
87
88    la      k0,     NB_PROCS_MAX     /* k0 <= # of processors per cluster   */
89    divu    t3,     k0
90    mfhi    t1                       /* t1 <= lpid       = pid % NB_PROCS   */
91    mflo    t2                       /* t2 <= cluster_xy = pid / NB_PROCS   */
92
93    /* All processors initialise the count register in CP0 */
94
95    mtc0    zero,   CP0_COUNT
96
97    /*
98     * All processors enable the WTI for XICU
99     * Each processor may have IRQ_PER_PROC irq outputs from the XICU
100     * In each cluster, the XICU base address depends on the cluster_xy
101     */
102
103    la      t3,     SEG_XCU_BASE      /* t3 <= ICU base address             */
104    move    t4,     t1                /* t4 <= local_id                     */
105    li      t5,     IRQ_PER_PROCESSOR /* t5 <= IRQ_PER_PROCESSOR            */
106    multu   t4,     t5
107    mflo    t6                       /* t6 <= IRQ_PER_PROC * local_id       */
108    sll     t4,     t6,     2        /* t4 <= OUT_INDEX = t6 * 4            */
109
110    li      t5,     (0xC << 7)       /* t5 <= FUNC      = XICU_MSK_WTI      */
111    or      t4,     t4,     t5       /* t4 <= FUNC | INDEX | 00             */
112    or      t5,     t3,     t4       /* t5 <= &XICU[MSK_WTI][OUT_INDEX]     */
113
114    /* All processors set WTI mask using the physical address extension */
115
116    li      t4,     1
117    sllv    t4,     t4,     t1       /* Set XICU[MSK_WTI][INDEX][local_id]  */
118
119    mtc2    t2,     CP2_PADDR_EXT    /* set PADDR extension                 */
120    sw      t4,     0(t5)            /* XICU[MSK_WTI][INDEX] <= t4          */
121    mtc2    zero,   CP2_PADDR_EXT    /* reset PADDR extension               */
122
123    /*
124     * Only processor 0 in cluster 0 loads and executes the boot-loader
125     * We have:
126     * t0: global pid
127     * t1: local pid
128     * t2: cluster_xy
129     * t3: xicu physical base address in cluster 0
130     */
131
132    bne     zero,   t0,     _reset_wait
133    nop
134
135    /* Processor 0 initializes stack pointer */
136
137    la      k0,     _stack
138    li      k1,     RESET_STACK_SIZE /* k1 <= P0 stack size                 */
139    addu    sp,     k0,     k1       /* P0 stack from base to (base + size) */
140
141    /* Processor 0 displays version for this reset code */
142
143    la      a0,     versionstr
144    jal     reset_puts
145    nop
146
147    /* Processor 0 initializes the block device */
148
149    jal     reset_ioc_init
150    nop
151
152    /*
153     * Processor 0 jumps to the reset_elf_loader routine passing as argument
154     * the block number in which is loaded the .elf file
155     */
156
157    li      a0,     RESET_LOADER_LBA
158    jal     reset_elf_loader
159    nop
160
161    /*
162     * Processor O jumps to the entry address defined in the .elf file, and
163     * returned by reset_elf_loader function.
164     * First argument is pointer to the preloader function vectors other
165     * function arguments are 0
166     */
167
168    la      a0,     preloader_vector
169    move    a1,     zero
170    move    a2,     zero
171    move    a3,     zero
172    jr      v0
173    nop
174
175    /*
176     * All processor (but processor 0) wait in low power mode until processor 0
177     * wakes them using an IPI.
178     * We have:
179     * t0: global id
180     * t1: local id
181     * t2: cluster id
182     * t3: xicu physical base address in cluster 0
183     */
184
185_reset_wait:
186
187    sll     t4,     t1,     2        /* t4 <= local_id * 4                  */
188    addu    t5,     t4,     t3       /* t5 <= &XICU[WTI_REG][local_id]      */
189
190    wait
191
192    /*
193     * All other processors, when exiting wait mode, read from XICU the address
194     * to jump.
195     * This address is the boot-loader entry address that has been written in
196     * the mailbox by the IPI sent by processor 0
197     */
198
199    mtc2    t2,     CP2_PADDR_EXT    /* set PADDR extension                 */
200    lw      k0,     0(t5)            /* k0 <= XICU[WTI_REG][local_id]       */
201    mtc2    zero,   CP2_PADDR_EXT    /* reset PADDR extension               */
202
203    jr      k0
204    nop
205
206/* Exception entry point */
207
208.org 0x0380
209_excep:
210    mfc0    a0,     CP0_STATUS       /* first arg is status                 */
211    mfc0    a1,     CP0_CAUSE        /* second arg is cause                 */
212    mfc0    a2,     CP0_EPC          /* third argc is epc                   */
213    mfc2    a3,     CP2_DBVAR        /* fourth argc is dbvar                */
214    nop
215    j       handle_except
216    nop
217
218    .end reset
219
220    .set reorder
221
222    .section .data
223
224_stack:
225
226    .space RESET_STACK_SIZE
227
228/*
229 * vim: tabstop=4 : shiftwidth=4 : expandtab
230 */
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