i386/junos/MIT/course/src/src.lab/fs/ide.c

   1 /*
   2  * Minimal PIO-based (non-interrupt-driven) IDE driver code.
   3  * For information about what all this IDE/ATA magic means,
   4  * see the materials available on the class references page.
   5  */
   6
   7 #include "fs.h"
   8 #include <inc/x86.h>
   9
  10 #define IDE_BSY         0x80
  11 #define IDE_DRDY        0x40
  12 #define IDE_DF          0x20
  13 #define IDE_ERR         0x01
  14
  15 static int diskno = 1;
  16
  17 static int
  18 ide_wait_ready(bool check_error)
  19 {
  20         int r;
  21
  22         while (((r = inb(0x1F7)) & (IDE_BSY|IDE_DRDY)) != IDE_DRDY)
  23                 /* do nothing */;
  24
  25         if (check_error && (r & (IDE_DF|IDE_ERR)) != 0)
  26                 return -1;
  27         return 0;
  28 }
  29
  30 bool
  31 ide_probe_disk1(void)
  32 {
  33         int r, x;
  34
  35         // wait for Device 0 to be ready
  36         ide_wait_ready(0);
  37
  38         // switch to Device 1
  39         outb(0x1F6, 0xE0 | (1<<4));
  40
  41         // check for Device 1 to be ready for a while
  42         for (x = 0;
  43              x < 1000 && ((r = inb(0x1F7)) & (IDE_BSY|IDE_DF|IDE_ERR)) != 0;
  44              x++)
  45                 /* do nothing */;
  46
  47         // switch back to Device 0
  48         outb(0x1F6, 0xE0 | (0<<4));
  49
  50         cprintf("Device 1 presence: %d\n", (x < 1000));
  51         return (x < 1000);
  52 }
  53
  54 void
  55 ide_set_disk(int d)
  56 {
  57         if (d != 0 && d != 1)
  58                 panic("bad disk number");
  59         diskno = d;
  60 }
  61
  62 int
  63 ide_read(uint32_t secno, void *dst, size_t nsecs)
  64 {
  65         int r;
  66
  67         assert(nsecs <= 256);
  68
  69         ide_wait_ready(0);
  70
  71         outb(0x1F2, nsecs);
  72         outb(0x1F3, secno & 0xFF);
  73         outb(0x1F4, (secno >> 8) & 0xFF);
  74         outb(0x1F5, (secno >> 16) & 0xFF);
  75         outb(0x1F6, 0xE0 | ((diskno&1)<<4) | ((secno>>24)&0x0F));
  76         outb(0x1F7, 0x20);      // CMD 0x20 means read sector
  77
  78         for (; nsecs > 0; nsecs--, dst += SECTSIZE) {
  79                 if ((r = ide_wait_ready(1)) < 0)
  80                         return r;
  81                 insl(0x1F0, dst, SECTSIZE/4);
  82         }
  83
  84         return 0;
  85 }
  86
  87 int
  88 ide_write(uint32_t secno, const void *src, size_t nsecs)
  89 {
  90         int r;
  91
  92         assert(nsecs <= 256);
  93
  94         ide_wait_ready(0);
  95
  96         outb(0x1F2, nsecs);
  97         outb(0x1F3, secno & 0xFF);
  98         outb(0x1F4, (secno >> 8) & 0xFF);
  99         outb(0x1F5, (secno >> 16) & 0xFF);
 100         outb(0x1F6, 0xE0 | ((diskno&1)<<4) | ((secno>>24)&0x0F));
 101         outb(0x1F7, 0x30);      // CMD 0x30 means write sector
 102
 103         for (; nsecs > 0; nsecs--, src += SECTSIZE) {
 104                 if ((r = ide_wait_ready(1)) < 0)
 105                         return r;
 106                 outsl(0x1F0, src, SECTSIZE/4);
 107         }
 108
 109         return 0;
 110 }
 111