source: trunk/softs/giet_tsar/reset.S @ 656

Last change on this file since 656 was 633, checked in by alain, 11 years ago

Bug fix in reset.S : The IOPIC initialisation must
be conditionned by the USE_EXT_IO variable.
File size: 6.0 KB
Line 
1/********************************************************************************
2*       File : reset.S
3*       Author : Alain Greiner
4*       Date : 15/01/2014
5*********************************************************************************
6* This is a boot code for a generic multi-clusters / multi-processors
7* TSAR architecture (up to 256 clusters / up to 4  processors per cluster).
8* The physical address is 40 bits, and the 8 MSB bits A[39:32] define the
9* cluster index.
10*
11* As we don't want to use the virtual memory, the physical address is
12* equal to  the virtual address (identity mapping) and all processors stacks
13* and code segments are allocated in the physical memory bank in cluster 0.
14*
15* Both the reset base address and the kernel base address must be redefined
16* to use a physical memory bank smaller than 2 Gbytes.
17*
18* There is one XCU iand one MMC per cluster.
19*
20* There is one IOPIC component in cluster_io.
21*
22* There is two sets of peripherals:
23*
24* 1) A block device and a single channel TTY controller are available
25*    in cluster(0,0).
26*
27* 2) Other peripherals (including another Blockdevice, a multi-channels TTY
28*    contrÃŽler, a Frame buffer) are located in cluster_io.
29*    For those externals peripherals, hardware interrupts (HWI) are translated
30*    to software interrupts (WTI) by and IOPIC component, that is programmed
31*    to route all SWI to to processor 0 in cluster (0,0).
32*
33* The boot sequence is the following:
34*   - Each processor initializes the stack pointer ($29) depending on proc_id.
35*   - Each processor initializes the CP0 EBASE register
36*       - Only processor 0 initializes the Interrupt vector.
37*       - Only processor 0 initializes the IOPIC component.
38*   - Each processor initializes its private XCU mask.
39*       - Each processor initializes the Status Register (SR)
40*       - Each processor jumps to the same main address in kernel mode...
41********************************************************************************/
42
43#include "hard_config.h"
44#include "mips32_registers.h"
45
46        .section .reset,"ax",@progbits
47
48        .extern seg_stack_base
49        .extern seg_xcu_base
50        .extern seg_pic_base
51    .extern seg_kcode_base
52        .extern _interrupt_vector
53        .extern _ioc_isr
54        .extern _mmc_isr
55    .extern _tty_isr
56    .extern main
57
58        .globl  reset                           
59        .ent    reset
60        .align  2
61
62reset:
63        .set noreorder
64
65/* each proc computes  proc_id, lpid, cluster_xy */
66    mfc0    $26,    CP0_PROCID
67    andi    $26,    $26,    0x3FF           /* at most 1024 processors */
68    move    $10,    $26                 /* $10 <= proc_id  */
69    li      $27,    NB_PROCS_MAX
70    divu    $26,    $27
71    mfhi    $11                         /* $11 <= lpid */
72    mflo    $12                         /* $12 <= cluster_xy */
73
74/* each proc initializes stack pointer (64K per processor) */
75    la      $27,    seg_stack_base
76    addi    $26,    $10,    1               /* $26 <= (proc_id + 1)           */
77    sll     $26,    $26,    14          /* $26 <= (proc_id + 1) * 16K     */
78    addu    $29,    $27,    $26             /* $29 <= seg_stack_base(proc_id) */
79
80/* each proc initializes CP0 EBASE register */
81    la      $26,    seg_kcode_base
82    mtc0    $26,    CP0_EBASE           /* CP0_EBASE <= seg_kcode_base */
83
84/* only proc (0,0,0) initializes interrupt vector for IOC, TTY, MMC     */
85    bne     $10,    $0,    reset_xcu
86    nop
87
88    la      $26,    _interrupt_vector   /* interrupt vector address                */
89    la      $27,    _mmc_isr
90    sw      $27,    32($26)             /* interrupt_vector[8] <= _mmc_isr         */
91    la      $27,    _ioc_isr
92    sw      $27,    36($26)             /* interrupt_vector[9] <= _ioc_isr         */
93    la      $27,    _tty_isr
94    sw      $27,    40($26)             /* interrupt_vector[10] <= _tty_isr        */
95
96/* only proc (0,0,0) initializes IOPIC : IOPIC_ADDRESS[i] <= &XICU[0].WTI_REG[i]   */
97
98    li      $26,    USE_EXT_IO
99    beq     $26,    $0,     reset_xcu   /* IOPIC not initialised if not USE_EXT_IO */
100
101    li      $20,    X_SIZE
102    addi    $20,    $20,    -1
103    sll     $20,    $20,    4
104    li      $21,    Y_SIZE
105    add     $22,    $20,    $21         /* $22 <= cluster(X_SIZE-1, Y_SIZE)        */
106
107    mtc2    $22,    CP2_PADDR_EXT       /* CP2_PADDR_EXT <= cluster_io             */
108
109    li      $24,    16                  /* $24  iteration (de)counter              */
110    la      $27,    seg_xcu_base        /* $27 <= &(XICU[0].WTI_REG[0])            */
111    la      $26,    seg_pic_base        /* $26 <= &IOPIC_ADDRESS[0]                */
112
113reset_loop:
114    sw      $27,    0($26)              /* IOPIC_ADDRESS[i] <= &XICU[0].WTI_REG[i] */
115    addi    $24,    $24,    -1          /* decrement iteration index               */
116    addi    $27,    $27,     4          /* $27 <= &(XICU[0].WTI_REG[i++]           */
117    addi    $26,    $26,     16         /* $26 <= &IOPIC_ADDRESS[i++]              */
118    bne     $24,    $0, reset_loop
119    nop
120
121    mtc2    $0,     CP2_PADDR_EXT       /* CP2_PADDR_EXT <= zero                   */
122   
123reset_xcu:
124
125/* only proc (x,y,0) receive IRQs and initialise HWI and WTI XICU masks */
126    bne     $11,    $0,     reset_end
127    nop
128    la      $26,    seg_xcu_base
129    li      $27,    0b010010000000      /* offset for MSK_HWI_ENABLE[lpid == 0]    */
130    addu    $24,    $26,    $27         /* $24 <= &HWI_MASK                        */
131    li      $25,    0x0700                      /* TTY:HWI[10]  IOC:HWI[9]  MEMC:HWI[8]    */
132    sw      $25,    0($24)              /* set HWI mask                            */
133
134    li      $27,    0b011010000000      /* offset for MSK_WTI_ENABLE[lpid == 0]    */
135    addu    $24,    $26,    $27         /* $24 <= $WTI_MASK                        */
136    li      $25,    0xFFFFFFFF          /* all WTI enabled                         */
137    sw      $25,    0($24)              /* set WTI mask                            */
138
139reset_end:
140
141/* initializes SR register */
142    li      $26,    0x0000FF01         
143    mtc0    $26,    $12                         /* SR <= kernel mode / IRQ enable */
144
145/* jumps to main in kernel mode */
146    la      $26,    main
147    jr      $26
148    nop
149
150    .end        reset
151
152    .set reorder
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