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  1. /*
  2.  * Copyright (C) 2001-2004 Jakub Jermar
  3.  * All rights reserved.
  4.  *
  5.  * Redistribution and use in source and binary forms, with or without
  6.  * modification, are permitted provided that the following conditions
  7.  * are met:
  8.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - Redistributions in binary form must reproduce the above copyright
  12.  *   notice, this list of conditions and the following disclaimer in the
  13.  *   documentation and/or other materials provided with the distribution.
  14.  * - The name of the author may not be used to endorse or promote products
  15.  *   derived from this software without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27.  */
  28.  
  29. #include <arch/types.h>
  30. #include <time/clock.h>
  31. #include <time/delay.h>
  32. #include <arch/interrupt.h>
  33. #include <arch/i8259.h>
  34. #include <arch/i8254.h>
  35. #include <cpu.h>
  36. #include <config.h>
  37. #include <arch/pm.h>
  38. #include <arch/asm.h>
  39. #include <arch/cpuid.h>
  40. #include <arch.h>
  41. #include <time/delay.h>
  42.  
  43. /*
  44.  * i8254 chip driver.
  45.  * Low level time functions.
  46.  */
  47.  
  48. #define CLK_PORT1   0x40
  49. #define CLK_PORT4   0x43
  50.  
  51.  
  52. #define CLK_CONST   1193180
  53. #define MAGIC_NUMBER    1194
  54.  
  55. void i8254_init(void)
  56. {
  57.     i8254_normal_operation();
  58. }
  59.  
  60. void i8254_normal_operation(void)
  61. {
  62.     outb(CLK_PORT4, 0x36);
  63.     trap_virtual_disable_irqs(1<<IRQ_CLK);
  64.     outb(CLK_PORT1, (CLK_CONST/HZ) & 0xf);
  65.     outb(CLK_PORT1, (CLK_CONST/HZ) >> 8);
  66.     trap_virtual_enable_irqs(1<<IRQ_CLK);
  67.     trap_register(VECTOR_CLK, i8254_interrupt);
  68. }
  69.  
  70. #define LOOPS 150000
  71. #define SHIFT 11
  72. void i8254_calibrate_delay_loop(void)
  73. {
  74.     __u64 clk1, clk2;
  75.     __u32 t1, t2, o1, o2;
  76.     __u8 not_ok;
  77.  
  78.  
  79.     /*
  80.      * One-shot timer. Count-down from 0xffff at 1193180Hz
  81.      * MAGIC_NUMBER is the magic value for 1ms.
  82.      */
  83.     outb(CLK_PORT4, 0x30);
  84.     outb(CLK_PORT1, 0xff);
  85.     outb(CLK_PORT1, 0xff);
  86.  
  87.     do {
  88.         /* will read both status and count */
  89.         outb(CLK_PORT4, 0xc2);
  90.         not_ok = (inb(CLK_PORT1)>>6)&1;
  91.         t1 = inb(CLK_PORT1);
  92.         t1 |= inb(CLK_PORT1) << 8;
  93.     } while (not_ok);
  94.  
  95.     asm_delay_loop(LOOPS);
  96.  
  97.     outb(CLK_PORT4, 0xd2);
  98.     t2 = inb(CLK_PORT1);
  99.     t2 |= inb(CLK_PORT1) << 8;
  100.  
  101.     /*
  102.      * We want to determine the overhead of the calibrating mechanism.
  103.      */
  104.     outb(CLK_PORT4, 0xd2);
  105.     o1 = inb(CLK_PORT1);
  106.     o1 |= inb(CLK_PORT1) << 8;
  107.  
  108.     asm_fake_loop(LOOPS);
  109.  
  110.     outb(CLK_PORT4, 0xd2);
  111.     o2 = inb(CLK_PORT1);
  112.     o2 |= inb(CLK_PORT1) << 8;
  113.  
  114.     CPU->delay_loop_const = ((MAGIC_NUMBER*LOOPS)/1000) / ((t1-t2)-(o1-o2)) + (((MAGIC_NUMBER*LOOPS)/1000) % ((t1-t2)-(o1-o2)) ? 1 : 0);
  115.  
  116.     clk1 = rdtsc();
  117.     delay(1<<SHIFT);
  118.     clk2 = rdtsc();
  119.    
  120.     CPU->frequency_mhz = (clk2-clk1)>>SHIFT;
  121.  
  122.     return;
  123. }
  124.  
  125. void i8254_interrupt(__u8 n, __native stack[])
  126. {
  127.     trap_virtual_eoi();
  128.     clock();
  129. }
  130.