i386/ucla/src/lab5/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 <inc/lib.h>
   8 #include "ide.h"
   9 #include <inc/x86.h>
  10
  11 #define IDE_BSY         0x80
  12 #define IDE_DRDY        0x40
  13 #define IDE_DF          0x20
  14 #define IDE_ERR         0x01
  15
  16 static int diskno = 1;
  17
  18 static int
  19 ide_wait_ready(bool check_error)
  20 {
  21         int r;
  22
  23         while (((r = inb(0x1F7)) & (IDE_BSY|IDE_DRDY)) != IDE_DRDY)
  24                 /* do nothing */;
  25
  26         if (check_error && (r & (IDE_DF|IDE_ERR)) != 0)
  27                 return -E_IO;
  28         return 0;
  29 }
  30
  31 bool
  32 ide_probe_disk1(void)
  33 {
  34         int r, x;
  35
  36         // wait for Device 0 to be ready
  37         ide_wait_ready(0);
  38
  39         // switch to Device 1
  40         outb(0x1F6, 0xE0 | (1<<4));
  41
  42         // check for Device 1 to be ready for a while
  43         for (x = 0;
  44              x < 1000 && ((r = inb(0x1F7)) & (IDE_BSY|IDE_DF|IDE_ERR)) != 0;
  45              x++)
  46                 /* do nothing */;
  47
  48         // switch back to Device 0
  49         outb(0x1F6, 0xE0 | (0<<4));
  50
  51         cprintf("Device 1 presence: %d\n", (x < 1000));
  52         return (x < 1000);
  53 }
  54
  55 void
  56 ide_set_disk(int d)
  57 {
  58         if (d != 0 && d != 1)
  59                 panic("bad disk number");
  60         diskno = d;
  61 }
  62
  63 int
  64 ide_read(uint32_t secno, void *dst_voidp, size_t nsecs)
  65 {
  66         char *dst = (char *) dst_voidp;
  67         int r;
  68
  69         assert(nsecs <= 256);
  70
  71         ide_wait_ready(0);
  72
  73         outb(0x1F2, nsecs);
  74         outb(0x1F3, secno & 0xFF);
  75         outb(0x1F4, (secno >> 8) & 0xFF);
  76         outb(0x1F5, (secno >> 16) & 0xFF);
  77         outb(0x1F6, 0xE0 | ((diskno&1)<<4) | ((secno>>24)&0x0F));
  78         outb(0x1F7, 0x20);      // CMD 0x20 means read sector
  79
  80         for (; nsecs > 0; nsecs--, dst += SECTSIZE) {
  81                 if ((r = ide_wait_ready(1)) < 0)
  82                         return r;
  83                 insl(0x1F0, dst, SECTSIZE/4);
  84         }
  85
  86         return 0;
  87 }
  88
  89 int
  90 ide_write(uint32_t secno, const void *src_voidp, size_t nsecs)
  91 {
  92         const char *src = (const char *) src_voidp;
  93         int r;
  94
  95         assert(nsecs <= 256);
  96
  97         ide_wait_ready(0);
  98
  99         outb(0x1F2, nsecs);
 100         outb(0x1F3, secno & 0xFF);
 101         outb(0x1F4, (secno >> 8) & 0xFF);
 102         outb(0x1F5, (secno >> 16) & 0xFF);
 103         outb(0x1F6, 0xE0 | ((diskno&1)<<4) | ((secno>>24)&0x0F));
 104         outb(0x1F7, 0x30);      // CMD 0x30 means write sector
 105
 106         for (; nsecs > 0; nsecs--, src += SECTSIZE) {
 107                 if ((r = ide_wait_ready(1)) < 0)
 108                         return r;
 109                 outsl(0x1F0, src, SECTSIZE/4);
 110         }
 111
 112         return 0;
 113 }