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1 | jermar | 1 | /* |
2071 | jermar | 2 | * Copyright (c) 2001-2004 Jakub Jermar |
1 | jermar | 3 | * All rights reserved. |
4 | * |
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5 | * Redistribution and use in source and binary forms, with or without |
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6 | * modification, are permitted provided that the following conditions |
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7 | * are met: |
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8 | * |
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9 | * - Redistributions of source code must retain the above copyright |
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10 | * notice, this list of conditions and the following disclaimer. |
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11 | * - Redistributions in binary form must reproduce the above copyright |
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12 | * notice, this list of conditions and the following disclaimer in the |
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13 | * documentation and/or other materials provided with the distribution. |
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14 | * - The name of the author may not be used to endorse or promote products |
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15 | * derived from this software without specific prior written permission. |
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16 | * |
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17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
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18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
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20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
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21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
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26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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27 | */ |
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28 | |||
1754 | jermar | 29 | /** @addtogroup ia32 |
1702 | cejka | 30 | * @{ |
31 | */ |
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1754 | jermar | 32 | /** |
33 | * @file |
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34 | * @brief i8254 chip driver. |
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35 | * |
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36 | * Low level time functions. |
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1702 | cejka | 37 | */ |
38 | |||
1 | jermar | 39 | #include <arch/types.h> |
40 | #include <time/clock.h> |
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41 | #include <time/delay.h> |
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2018 | decky | 42 | #include <arch/cycle.h> |
1 | jermar | 43 | #include <arch/interrupt.h> |
1477 | decky | 44 | #include <arch/drivers/i8259.h> |
45 | #include <arch/drivers/i8254.h> |
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1 | jermar | 46 | #include <cpu.h> |
47 | #include <config.h> |
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48 | #include <arch/pm.h> |
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49 | #include <arch/asm.h> |
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195 | vana | 50 | #include <arch/cpuid.h> |
1 | jermar | 51 | #include <arch.h> |
195 | vana | 52 | #include <time/delay.h> |
1956 | decky | 53 | #include <ddi/irq.h> |
54 | #include <ddi/device.h> |
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1 | jermar | 55 | |
56 | #define CLK_PORT1 0x40 |
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57 | #define CLK_PORT4 0x43 |
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58 | |||
59 | #define CLK_CONST 1193180 |
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60 | #define MAGIC_NUMBER 1194 |
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61 | |||
1956 | decky | 62 | static irq_t i8254_irq; |
576 | palkovsky | 63 | |
1956 | decky | 64 | static irq_ownership_t i8254_claim(void) |
65 | { |
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66 | return IRQ_ACCEPT; |
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67 | } |
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68 | |||
69 | static void i8254_irq_handler(irq_t *irq, void *arg, ...) |
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70 | { |
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2107 | jermar | 71 | /* |
72 | * This IRQ is responsible for kernel preemption. |
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73 | * Nevertheless, we are now holding a spinlock which prevents |
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74 | * preemption. For this particular IRQ, we don't need the |
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75 | * lock. We just release it, call clock() and then reacquire it again. |
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76 | */ |
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77 | spinlock_unlock(&irq->lock); |
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1956 | decky | 78 | clock(); |
2107 | jermar | 79 | spinlock_lock(&irq->lock); |
1956 | decky | 80 | } |
81 | |||
1 | jermar | 82 | void i8254_init(void) |
83 | { |
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1956 | decky | 84 | irq_initialize(&i8254_irq); |
85 | i8254_irq.devno = device_assign_devno(); |
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86 | i8254_irq.inr = IRQ_CLK; |
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87 | i8254_irq.claim = i8254_claim; |
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88 | i8254_irq.handler = i8254_irq_handler; |
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89 | irq_register(&i8254_irq); |
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90 | |||
1 | jermar | 91 | i8254_normal_operation(); |
92 | } |
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93 | |||
94 | void i8254_normal_operation(void) |
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95 | { |
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96 | outb(CLK_PORT4, 0x36); |
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1956 | decky | 97 | pic_disable_irqs(1 << IRQ_CLK); |
98 | outb(CLK_PORT1, (CLK_CONST / HZ) & 0xf); |
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99 | outb(CLK_PORT1, (CLK_CONST / HZ) >> 8); |
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100 | pic_enable_irqs(1 << IRQ_CLK); |
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1 | jermar | 101 | } |
102 | |||
103 | #define LOOPS 150000 |
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104 | #define SHIFT 11 |
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105 | void i8254_calibrate_delay_loop(void) |
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106 | { |
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1780 | jermar | 107 | uint64_t clk1, clk2; |
108 | uint32_t t1, t2, o1, o2; |
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109 | uint8_t not_ok; |
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1 | jermar | 110 | |
111 | |||
112 | /* |
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113 | * One-shot timer. Count-down from 0xffff at 1193180Hz |
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114 | * MAGIC_NUMBER is the magic value for 1ms. |
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115 | */ |
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116 | outb(CLK_PORT4, 0x30); |
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117 | outb(CLK_PORT1, 0xff); |
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118 | outb(CLK_PORT1, 0xff); |
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119 | |||
120 | do { |
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125 | jermar | 121 | /* will read both status and count */ |
1 | jermar | 122 | outb(CLK_PORT4, 0xc2); |
123 | not_ok = (inb(CLK_PORT1)>>6)&1; |
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124 | t1 = inb(CLK_PORT1); |
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125 | t1 |= inb(CLK_PORT1) << 8; |
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126 | } while (not_ok); |
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127 | |||
128 | asm_delay_loop(LOOPS); |
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129 | |||
130 | outb(CLK_PORT4, 0xd2); |
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131 | t2 = inb(CLK_PORT1); |
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132 | t2 |= inb(CLK_PORT1) << 8; |
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133 | |||
134 | /* |
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135 | * We want to determine the overhead of the calibrating mechanism. |
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136 | */ |
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137 | outb(CLK_PORT4, 0xd2); |
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138 | o1 = inb(CLK_PORT1); |
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139 | o1 |= inb(CLK_PORT1) << 8; |
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140 | |||
141 | asm_fake_loop(LOOPS); |
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142 | |||
143 | outb(CLK_PORT4, 0xd2); |
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144 | o2 = inb(CLK_PORT1); |
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145 | o2 |= inb(CLK_PORT1) << 8; |
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146 | |||
2107 | jermar | 147 | CPU->delay_loop_const = |
148 | ((MAGIC_NUMBER * LOOPS) / 1000) / ((t1 - t2) - (o1 - o2)) + |
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149 | (((MAGIC_NUMBER * LOOPS) / 1000) % ((t1 - t2) - (o1 - o2)) ? 1 : 0); |
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1 | jermar | 150 | |
2018 | decky | 151 | clk1 = get_cycle(); |
152 | delay(1 << SHIFT); |
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153 | clk2 = get_cycle(); |
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1 | jermar | 154 | |
2018 | decky | 155 | CPU->frequency_mhz = (clk2 - clk1) >> SHIFT; |
1 | jermar | 156 | |
157 | return; |
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158 | } |
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159 | |||
1754 | jermar | 160 | /** @} |
1702 | cejka | 161 | */ |