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    /*
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/*
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 * Copyright (c) 2007 Petr Stepan
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 * Copyright (c) 2007 Petr Stepan
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 * All rights reserved.
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 * All rights reserved.
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 *
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * modification, are permitted provided that the following conditions
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 */
 34 
 */
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 35 
 
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#include <arch/exception.h>
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#include <arch/exception.h>
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#include "aux_print/printf.h"
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#include "aux_print/printf.h"
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#include <arch/memstr.h>
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#include <arch/memstr.h>
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 39 
#include <arch/regutils.h>
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 40 
#include <interrupt.h>
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 42 
 
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#define PREFETCH_OFFSET     0x8
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#define PREFETCH_OFFSET     0x8
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#define BRANCH_OPCODE       0xea000000
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#define BRANCH_OPCODE       0xea000000
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#define LDR_OPCODE      0xe59ff000
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#define VALID_BRANCH_MASK   0xff000000
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#define VALID_BRANCH_MASK   0xff000000
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#define EXC_VECTORS_SIZE    0x20
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#define EXC_VECTORS     0x8
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 49 
 
- 
 
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/* GXEmul interrupt controller macros
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/** Updates specified exception vector to jump to given handler.
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TODO might go to drivers/ together with servicing functions
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*/
 52 
*/
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static void install_handler (unsigned* handler, unsigned* vector) {
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/* IRQ Controller device is added in a special premium gxemul
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 * edition at www.ms.mff.cuni.cz/~stepp3am/mygxemul-0.4.4.1.tar.gz
- 
 
 55 
 * :)
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 56 
 */
- 
 
 57 
#define IRQ_CONTROLLER_CAUSE    0x0000000016000000
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#define IRQ_CONTROLLER_MAX_IRQ  8
- 
 
 59 
 
- 
 
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/* IRQs */
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 61 
#define CONSOLE_IRQ     2
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    volatile unsigned vec;
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#define TIMER_IRQ       4
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 63 
 
48 
   
 64 
 
49 
    /* calculate relative distance */
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#define SAVE_REGS_TO_STACK          \
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    vec = ((unsigned)handler - (unsigned)vector - PREFETCH_OFFSET);
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    asm("stmfd sp!, {r0-r12, sp, lr}");     \
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    asm("mrs r14, spsr");           \
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    asm("stmfd sp!, {r14}");
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 69 
 
- 
 
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#define CALL_EXC_DISPATCH(exception)        \
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    asm("mov r0, %0" : : "i" (exception));  \
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    /* word offset */
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    asm("mov r1, sp");          \
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    asm("bl exc_dispatch");    
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 74 
 
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/**Loads registers from the stack and resets SPSR before exitting exception
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    vec >>= 2;
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 * handler.
- 
 
 77 
 */
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 78 
#define LOAD_REGS_FROM_STACK            \
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    asm("ldmfd sp!, {r14}");        \
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    asm("msr spsr, r14");           \
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    asm("ldmfd sp!, {r0-r12, sp, pc}^");
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 82 
   
- 
 
 83 
/** General exception handler.
55 
    /* check if haven't jumped beyond 32 MB */
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 *  Stores registers, dispatches the exception,
- 
 
 85 
 *  and finally restores registers and returns from exception processing.
- 
 
 86 
 */
- 
 
 87 
#define PROCESS_EXCEPTION(exception)        \
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    SAVE_REGS_TO_STACK          \
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    if ((vec & VALID_BRANCH_MASK) != 0) {
 89 
    CALL_EXC_DISPATCH(exception)        \
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    LOAD_REGS_FROM_STACK           
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 91 
 
57 
        /*panic("exception handler beyond 32MB.");*/
 92 
/** Updates specified exception vector to jump to given handler.
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 93 
 * Addresses of handlers are stored in memory following exception vectors.
58 
        return;
 94 
 */
- 
 
 95 
static void install_handler (unsigned handler_addr, unsigned* vector)
- 
 
 96 
{
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 97 
    /* relative address (related to exc. vector) of the word
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     * where handler's address is stored
59 
    }
 99 
    */
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 100 
    volatile uint32_t handler_address_ptr = EXC_VECTORS_SIZE - PREFETCH_OFFSET;
60 
   
 101 
   
61 
    /* make it branch instruction */
 102 
    /* make it LDR instruction and store at exception vector */
62 
    vec |= BRANCH_OPCODE;
 103 
    *vector = handler_address_ptr | LDR_OPCODE;
63 
    *vector = vec;
 - 
 
64 
   
 104 
   
- 
 
 105 
    /* store handler's address */
- 
 
 106 
    *(vector + EXC_VECTORS) = handler_addr;
- 
 
 107 
}
- 
 
 108 
 
- 
 
 109 
static void reset_exception_entry()
- 
 
 110 
{
- 
 
 111 
    PROCESS_EXCEPTION(EXC_RESET);
- 
 
 112 
}
- 
 
 113 
 
- 
 
 114 
/** Low-level Software Interrupt Exception handler */
- 
 
 115 
static void swi_exception_entry()
- 
 
 116 
{
- 
 
 117 
    PROCESS_EXCEPTION(EXC_SWI);
- 
 
 118 
}
- 
 
 119 
 
65 
    aux_printf("installed  handler to %p, to vector %p\n.", handler, vector);
 120 
/** Low-level Undefined Instruction Exception handler */
- 
 
 121 
static void undef_instr_exception_entry()
- 
 
 122 
{
- 
 
 123 
    PROCESS_EXCEPTION(EXC_UNDEF_INSTR);
- 
 
 124 
}
- 
 
 125 
 
- 
 
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/** Low-level Fast Interrupt Exception handler */
- 
 
 127 
static void fiq_exception_entry()
- 
 
 128 
{
- 
 
 129 
    PROCESS_EXCEPTION(EXC_FIQ);
66 
}
 130 
}
67 
 
 131 
 
- 
 
 132 
/** Low-level Prefetch Abort Exception handler */
- 
 
 133 
static void prefetch_abort_exception_entry()
- 
 
 134 
{
- 
 
 135 
    asm("sub lr, lr, #4");
- 
 
 136 
    PROCESS_EXCEPTION(EXC_PREFETCH_ABORT);
- 
 
 137 
}
- 
 
 138 
 
68 
/* TODO add other exception handlers */
 139 
/** Low-level Data Abort Exception handler */
69 
static void dummy_exception(){
 140 
static void data_abort_exception_entry()
- 
 
 141 
{
70 
    asm("bkpt");
 142 
    asm("sub lr, lr, #8");
- 
 
 143 
    PROCESS_EXCEPTION(EXC_DATA_ABORT);
71 
}
 144 
}
72 
 
 145 
 
- 
 
 146 
 
73 
/** IRQ Exception handler */
 147 
/** Low-level Interrupt Exception handler */
74 
static void irq_exception(){
 148 
static void irq_exception_entry()
- 
 
 149 
{
75 
    asm("bkpt");
 150 
    asm("sub lr, lr, #4");
- 
 
 151 
    PROCESS_EXCEPTION(EXC_IRQ);
- 
 
 152 
}
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 153 
 
- 
 
 154 
 
- 
 
 155 
/** Interrupt Exception handler.
- 
 
 156 
 * Determines the sources of interrupt, and calls their handlers.
- 
 
 157 
 */
- 
 
 158 
static void irq_exception(int exc_no, istate_t* istate)
- 
 
 159 
{
- 
 
 160 
    /* TODO this will call interrupt dispatching routine
- 
 
 161 
     *
- 
 
 162 
     */
- 
 
 163 
 
- 
 
 164 
    uint32_t sources = *(uint32_t*) IRQ_CONTROLLER_CAUSE;
- 
 
 165 
    int i = 0;
- 
 
 166 
    int noirq = 1;
- 
 
 167 
    for (; i < IRQ_CONTROLLER_MAX_IRQ; i++) {
- 
 
 168 
        if (sources & (1 << i)) {
- 
 
 169 
            noirq = 0;
- 
 
 170 
            if (i == CONSOLE_IRQ) {
- 
 
 171 
                char readchar = *(char*)0x10000000;
- 
 
 172 
                if (readchar == 0) {
- 
 
 173 
                    aux_puts("?");
- 
 
 174 
                }
- 
 
 175 
                else {
- 
 
 176 
                    aux_printf("%c", readchar);
- 
 
 177 
                }
- 
 
 178 
               
- 
 
 179 
            }
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 180 
            else if (i == TIMER_IRQ) {
- 
 
 181 
                aux_printf("\n.\n");
- 
 
 182 
                /* acknowledge  */
- 
 
 183 
                *(uint32_t*)0x15000110 = 0;
- 
 
 184 
            }
- 
 
 185 
        }
- 
 
 186 
    }
- 
 
 187 
 
- 
 
 188 
    if (noirq)
- 
 
 189 
        aux_puts("IRQ exception without source\n");
76 
}
 190 
}
77 
 
 191 
 
78 
/** Fills exception vectors with appropriate exception handlers.
 192 
/** Fills exception vectors with appropriate exception handlers.
79 
*/
 193 
*/
80 
void install_exception_handlers(void) {
 194 
void install_exception_handlers(void)
- 
 
 195 
{
81 
    install_handler((unsigned*)dummy_exception, (unsigned*)EXC_RESET_VEC);
 196 
    install_handler((unsigned)reset_exception_entry,
- 
 
 197 
             (unsigned*)EXC_RESET_VEC);
- 
 
 198 
   
82 
    install_handler((unsigned*)dummy_exception, (unsigned*)EXC_UNDEF_INSTR_VEC);
 199 
    install_handler((unsigned)undef_instr_exception_entry,
- 
 
 200 
             (unsigned*)EXC_UNDEF_INSTR_VEC);
- 
 
 201 
   
83 
    install_handler((unsigned*)dummy_exception, (unsigned*)EXC_SWI_VEC);
 202 
    install_handler((unsigned)swi_exception_entry,
- 
 
 203 
             (unsigned*)EXC_SWI_VEC);
- 
 
 204 
   
84 
    install_handler((unsigned*)dummy_exception, (unsigned*)EXC_PREFETCH_ABORT_VEC);
 205 
    install_handler((unsigned)prefetch_abort_exception_entry,
- 
 
 206 
             (unsigned*)EXC_PREFETCH_ABORT_VEC);
- 
 
 207 
   
85 
    install_handler((unsigned*)dummy_exception, (unsigned*)EXC_DATA_ABORT_VEC);
 208 
    install_handler((unsigned)data_abort_exception_entry,
- 
 
 209 
             (unsigned*)EXC_DATA_ABORT_VEC);
- 
 
 210 
   
86 
    install_handler((unsigned*)irq_exception,   (unsigned*)EXC_IRQ_VEC);
 211 
    install_handler((unsigned)irq_exception_entry,  
- 
 
 212 
             (unsigned*)EXC_IRQ_VEC);
- 
 
 213 
   
87 
    install_handler((unsigned*)dummy_exception, (unsigned*)EXC_FIQ_VEC);
 214 
    install_handler((unsigned)fiq_exception_entry,
- 
 
 215 
             (unsigned*)EXC_FIQ_VEC);
88 
}
 216 
}
89 
 
 217 
 
90 
/** Registers exceptions and their handlers to kernel exception dispatcher. */
 218 
/** Registers exceptions and their handlers to kernel exception dispatcher. */
91 
void exception_init(void){
 219 
void exception_init(void)
- 
 
 220 
{
- 
 
 221 
    exc_register(EXC_IRQ, "interrupt", (iroutine) irq_exception);
92 
    /* TODO */
 222 
    /* TODO add next */
- 
 
 223 
}
- 
 
 224 
 
- 
 
 225 
/* TODO change soon, temporary hack. */
- 
 
 226 
void setup_exception_stacks()
- 
 
 227 
{
- 
 
 228 
    /* switch to particular mode and set "sp" there */
- 
 
 229 
    uint32_t cspr = current_status_reg_read();
- 
 
 230 
    current_status_reg_control_write(
- 
 
 231 
            (cspr & ~STATUS_REG_MODE_MASK) | IRQ_MODE
- 
 
 232 
    );
- 
 
 233 
    asm("ldr sp, =irq_stack");
- 
 
 234 
    current_status_reg_control_write( cspr);
93 
}
 235 
}
94 
 
 236 
 
95 
/** @}
 237 
/** @}
96 
 */
 238 
 */