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| Rev | Author | Line No. | Line |
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| 2292 | hudecek | 1 | /* |
| 2 | * Copyright (c) 2001-2004 Jakub Jermar |
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| 3 | * All rights reserved. |
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| 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 | |||
| 29 | /** @addtogroup ia32 |
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| 30 | * @{ |
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| 31 | */ |
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| 32 | /** |
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| 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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| 37 | */ |
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| 38 | |||
| 39 | #include <arch/types.h> |
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| 40 | #include <time/clock.h> |
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| 41 | #include <time/delay.h> |
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| 42 | #include <arch/cycle.h> |
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| 43 | #include <arch/interrupt.h> |
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| 44 | #include <arch/drivers/i8259.h> |
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| 45 | #include <arch/drivers/i8254.h> |
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| 46 | #include <cpu.h> |
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| 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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| 50 | #include <arch/cpuid.h> |
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| 51 | #include <arch.h> |
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| 52 | #include <time/delay.h> |
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| 53 | #include <ddi/irq.h> |
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| 54 | #include <ddi/device.h> |
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| 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 | |||
| 62 | static irq_t i8254_irq; |
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| 63 | |||
| 64 | static irq_ownership_t i8254_claim(void) |
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| 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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| 71 | /* |
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| 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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| 78 | clock(); |
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| 79 | spinlock_lock(&irq->lock); |
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| 80 | } |
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| 81 | |||
| 82 | void i8254_init(void) |
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| 83 | { |
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| 84 | irq_initialize(&i8254_irq); |
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| 2307 | hudecek | 85 | i8254_irq.preack = true; |
| 2292 | hudecek | 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 | |||
| 92 | i8254_normal_operation(); |
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| 93 | } |
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| 94 | |||
| 95 | void i8254_normal_operation(void) |
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| 96 | { |
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| 97 | outb(CLK_PORT4, 0x36); |
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| 98 | pic_disable_irqs(1 << IRQ_CLK); |
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| 99 | outb(CLK_PORT1, (CLK_CONST / HZ) & 0xf); |
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| 100 | outb(CLK_PORT1, (CLK_CONST / HZ) >> 8); |
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| 101 | pic_enable_irqs(1 << IRQ_CLK); |
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| 102 | } |
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| 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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| 108 | uint64_t clk1, clk2; |
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| 109 | uint32_t t1, t2, o1, o2; |
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| 110 | uint8_t not_ok; |
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| 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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| 117 | outb(CLK_PORT4, 0x30); |
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| 118 | outb(CLK_PORT1, 0xff); |
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| 119 | outb(CLK_PORT1, 0xff); |
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| 120 | |||
| 121 | do { |
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| 122 | /* will read both status and count */ |
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| 123 | outb(CLK_PORT4, 0xc2); |
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| 124 | not_ok = (inb(CLK_PORT1)>>6)&1; |
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| 125 | t1 = inb(CLK_PORT1); |
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| 126 | t1 |= inb(CLK_PORT1) << 8; |
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| 127 | } while (not_ok); |
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| 128 | |||
| 129 | asm_delay_loop(LOOPS); |
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| 130 | |||
| 131 | outb(CLK_PORT4, 0xd2); |
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| 132 | t2 = inb(CLK_PORT1); |
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| 133 | t2 |= inb(CLK_PORT1) << 8; |
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| 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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| 138 | outb(CLK_PORT4, 0xd2); |
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| 139 | o1 = inb(CLK_PORT1); |
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| 140 | o1 |= inb(CLK_PORT1) << 8; |
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| 141 | |||
| 142 | asm_fake_loop(LOOPS); |
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| 143 | |||
| 144 | outb(CLK_PORT4, 0xd2); |
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| 145 | o2 = inb(CLK_PORT1); |
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| 146 | o2 |= inb(CLK_PORT1) << 8; |
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| 147 | |||
| 148 | CPU->delay_loop_const = |
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| 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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| 151 | |||
| 152 | clk1 = get_cycle(); |
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| 153 | delay(1 << SHIFT); |
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| 154 | clk2 = get_cycle(); |
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| 155 | |||
| 156 | CPU->frequency_mhz = (clk2 - clk1) >> SHIFT; |
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| 157 | |||
| 158 | return; |
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| 159 | } |
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| 160 | |||
| 161 | /** @} |
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| 162 | */ |