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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 | /* * linux/arch/arm26/kernel/fiq.c * * Copyright (C) 1998 Russell King * Copyright (C) 1998, 1999 Phil Blundell * Copyright (C) 2003 Ian Molton * * FIQ support written by Philip Blundell <philb@gnu.org>, 1998. * * FIQ support re-written by Russell King to be more generic * * We now properly support a method by which the FIQ handlers can * be stacked onto the vector. We still do not support sharing * the FIQ vector itself. * * Operation is as follows: * 1. Owner A claims FIQ: * - default_fiq relinquishes control. * 2. Owner A: * - inserts code. * - sets any registers, * - enables FIQ. * 3. Owner B claims FIQ: * - if owner A has a relinquish function. * - disable FIQs. * - saves any registers. * - returns zero. * 4. Owner B: * - inserts code. * - sets any registers, * - enables FIQ. * 5. Owner B releases FIQ: * - Owner A is asked to reacquire FIQ: * - inserts code. * - restores saved registers. * - enables FIQ. * 6. Goto 3 */ #include <linux/config.h> #include <linux/module.h> #include <linux/mm.h> #include <linux/mman.h> #include <linux/init.h> #include <linux/seq_file.h> #include <asm/fiq.h> #include <asm/io.h> #include <asm/irq.h> #include <asm/pgalloc.h> #include <asm/system.h> #include <asm/uaccess.h> #define FIQ_VECTOR (vectors_base() + 0x1c) static unsigned long no_fiq_insn; #define unprotect_page_0() #define protect_page_0() /* Default reacquire function * - we always relinquish FIQ control * - we always reacquire FIQ control */ static int fiq_def_op(void *ref, int relinquish) { if (!relinquish) { unprotect_page_0(); *(unsigned long *)FIQ_VECTOR = no_fiq_insn; protect_page_0(); } return 0; } static struct fiq_handler default_owner = { .name = "default", .fiq_op = fiq_def_op, }; static struct fiq_handler *current_fiq = &default_owner; int show_fiq_list(struct seq_file *p, void *v) { if (current_fiq != &default_owner) seq_printf(p, "FIQ: %s\n", current_fiq->name); return 0; } void set_fiq_handler(void *start, unsigned int length) { unprotect_page_0(); memcpy((void *)FIQ_VECTOR, start, length); protect_page_0(); } /* * Taking an interrupt in FIQ mode is death, so both these functions * disable irqs for the duration. */ void set_fiq_regs(struct pt_regs *regs) { register unsigned long tmp, tmp2; __asm__ volatile ( "mov %0, pc \n" "bic %1, %0, #0x3 \n" "orr %1, %1, %3 \n" "teqp %1, #0 @ select FIQ mode \n" "mov r0, r0 \n" "ldmia %2, {r8 - r14} \n" "teqp %0, #0 @ return to SVC mode \n" "mov r0, r0 " : "=&r" (tmp), "=&r" (tmp2) : "r" (®s->ARM_r8), "I" (PSR_I_BIT | PSR_F_BIT | MODE_FIQ26) /* These registers aren't modified by the above code in a way visible to the compiler, but we mark them as clobbers anyway so that GCC won't put any of the input or output operands in them. */ : "r8", "r9", "r10", "r11", "r12", "r13", "r14"); } void get_fiq_regs(struct pt_regs *regs) { register unsigned long tmp, tmp2; __asm__ volatile ( "mov %0, pc \n" "bic %1, %0, #0x3 \n" "orr %1, %1, %3 \n" "teqp %1, #0 @ select FIQ mode \n" "mov r0, r0 \n" "stmia %2, {r8 - r14} \n" "teqp %0, #0 @ return to SVC mode \n" "mov r0, r0 " : "=&r" (tmp), "=&r" (tmp2) : "r" (®s->ARM_r8), "I" (PSR_I_BIT | PSR_F_BIT | MODE_FIQ26) /* These registers aren't modified by the above code in a way visible to the compiler, but we mark them as clobbers anyway so that GCC won't put any of the input or output operands in them. */ : "r8", "r9", "r10", "r11", "r12", "r13", "r14"); } int claim_fiq(struct fiq_handler *f) { int ret = 0; if (current_fiq) { ret = -EBUSY; if (current_fiq->fiq_op != NULL) ret = current_fiq->fiq_op(current_fiq->dev_id, 1); } if (!ret) { f->next = current_fiq; current_fiq = f; } return ret; } void release_fiq(struct fiq_handler *f) { if (current_fiq != f) { printk(KERN_ERR "%s FIQ trying to release %s FIQ\n", f->name, current_fiq->name); #ifdef CONFIG_DEBUG_ERRORS __backtrace(); #endif return; } do current_fiq = current_fiq->next; while (current_fiq->fiq_op(current_fiq->dev_id, 0)); } void enable_fiq(int fiq) { enable_irq(fiq + FIQ_START); } void disable_fiq(int fiq) { disable_irq(fiq + FIQ_START); } EXPORT_SYMBOL(set_fiq_handler); EXPORT_SYMBOL(set_fiq_regs); EXPORT_SYMBOL(get_fiq_regs); EXPORT_SYMBOL(claim_fiq); EXPORT_SYMBOL(release_fiq); EXPORT_SYMBOL(enable_fiq); EXPORT_SYMBOL(disable_fiq); void __init init_FIQ(void) { no_fiq_insn = *(unsigned long *)FIQ_VECTOR; set_fs(get_fs()); } |