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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 | |||
4377 | svoboda | 29 | /** @addtogroup ia32 |
1702 | cejka | 30 | * @{ |
31 | */ |
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1754 | jermar | 32 | /** |
33 | * @file |
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4377 | svoboda | 34 | * @brief i8254 chip driver. |
1754 | jermar | 35 | * |
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 | |
4377 | svoboda | 56 | #define CLK_PORT1 ((ioport8_t *)0x40) |
57 | #define CLK_PORT4 ((ioport8_t *)0x43) |
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1 | jermar | 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 | |
4377 | svoboda | 64 | static irq_ownership_t i8254_claim(irq_t *irq) |
1956 | decky | 65 | { |
66 | return IRQ_ACCEPT; |
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67 | } |
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68 | |||
4377 | svoboda | 69 | static void i8254_irq_handler(irq_t *irq) |
1956 | decky | 70 | { |
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); |
2218 | decky | 85 | i8254_irq.preack = true; |
1956 | decky | 86 | i8254_irq.devno = device_assign_devno(); |
87 | i8254_irq.inr = IRQ_CLK; |
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88 | i8254_irq.claim = i8254_claim; |
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89 | i8254_irq.handler = i8254_irq_handler; |
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90 | irq_register(&i8254_irq); |
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91 | |||
1 | jermar | 92 | i8254_normal_operation(); |
93 | } |
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94 | |||
95 | void i8254_normal_operation(void) |
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96 | { |
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4377 | svoboda | 97 | pio_write_8(CLK_PORT4, 0x36); |
1956 | decky | 98 | pic_disable_irqs(1 << IRQ_CLK); |
4377 | svoboda | 99 | pio_write_8(CLK_PORT1, (CLK_CONST / HZ) & 0xf); |
100 | pio_write_8(CLK_PORT1, (CLK_CONST / HZ) >> 8); |
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1956 | decky | 101 | pic_enable_irqs(1 << IRQ_CLK); |
1 | jermar | 102 | } |
103 | |||
104 | #define LOOPS 150000 |
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105 | #define SHIFT 11 |
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106 | void i8254_calibrate_delay_loop(void) |
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107 | { |
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1780 | jermar | 108 | uint64_t clk1, clk2; |
109 | uint32_t t1, t2, o1, o2; |
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110 | uint8_t not_ok; |
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1 | jermar | 111 | |
112 | |||
113 | /* |
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114 | * One-shot timer. Count-down from 0xffff at 1193180Hz |
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115 | * MAGIC_NUMBER is the magic value for 1ms. |
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116 | */ |
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4377 | svoboda | 117 | pio_write_8(CLK_PORT4, 0x30); |
118 | pio_write_8(CLK_PORT1, 0xff); |
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119 | pio_write_8(CLK_PORT1, 0xff); |
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1 | jermar | 120 | |
121 | do { |
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125 | jermar | 122 | /* will read both status and count */ |
4377 | svoboda | 123 | pio_write_8(CLK_PORT4, 0xc2); |
124 | not_ok = (uint8_t) ((pio_read_8(CLK_PORT1) >> 6) & 1); |
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125 | t1 = pio_read_8(CLK_PORT1); |
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126 | t1 |= pio_read_8(CLK_PORT1) << 8; |
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1 | jermar | 127 | } while (not_ok); |
128 | |||
129 | asm_delay_loop(LOOPS); |
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130 | |||
4377 | svoboda | 131 | pio_write_8(CLK_PORT4, 0xd2); |
132 | t2 = pio_read_8(CLK_PORT1); |
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133 | t2 |= pio_read_8(CLK_PORT1) << 8; |
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1 | jermar | 134 | |
135 | /* |
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136 | * We want to determine the overhead of the calibrating mechanism. |
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137 | */ |
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4377 | svoboda | 138 | pio_write_8(CLK_PORT4, 0xd2); |
139 | o1 = pio_read_8(CLK_PORT1); |
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140 | o1 |= pio_read_8(CLK_PORT1) << 8; |
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1 | jermar | 141 | |
142 | asm_fake_loop(LOOPS); |
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143 | |||
4377 | svoboda | 144 | pio_write_8(CLK_PORT4, 0xd2); |
145 | o2 = pio_read_8(CLK_PORT1); |
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146 | o2 |= pio_read_8(CLK_PORT1) << 8; |
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1 | jermar | 147 | |
2107 | jermar | 148 | CPU->delay_loop_const = |
149 | ((MAGIC_NUMBER * LOOPS) / 1000) / ((t1 - t2) - (o1 - o2)) + |
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150 | (((MAGIC_NUMBER * LOOPS) / 1000) % ((t1 - t2) - (o1 - o2)) ? 1 : 0); |
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1 | jermar | 151 | |
2018 | decky | 152 | clk1 = get_cycle(); |
153 | delay(1 << SHIFT); |
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154 | clk2 = get_cycle(); |
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1 | jermar | 155 | |
2018 | decky | 156 | CPU->frequency_mhz = (clk2 - clk1) >> SHIFT; |
1 | jermar | 157 | |
158 | return; |
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159 | } |
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160 | |||
1754 | jermar | 161 | /** @} |
1702 | cejka | 162 | */ |