113 lines
2.0 KiB
C
113 lines
2.0 KiB
C
/*
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* Minimal PIO-based (non-interrupt-driven) IDE driver code.
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* For information about what all this IDE/ATA magic means,
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* see the materials available on the class references page.
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*/
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#include "fs.h"
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#include <inc/x86.h>
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#define IDE_BSY 0x80
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#define IDE_DRDY 0x40
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#define IDE_DF 0x20
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#define IDE_ERR 0x01
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static int diskno = 1;
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static int
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ide_wait_ready(bool check_error)
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{
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int r;
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while (((r = inb(0x1F7)) & (IDE_BSY|IDE_DRDY)) != IDE_DRDY)
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/* do nothing */;
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if (check_error && (r & (IDE_DF|IDE_ERR)) != 0)
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return -1;
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return 0;
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}
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bool
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ide_probe_disk1(void)
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{
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int r, x;
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// wait for Device 0 to be ready
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ide_wait_ready(0);
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// switch to Device 1
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outb(0x1F6, 0xE0 | (1<<4));
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// check for Device 1 to be ready for a while
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for (x = 0;
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x < 1000 && ((r = inb(0x1F7)) & (IDE_BSY|IDE_DF|IDE_ERR)) != 0;
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x++)
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/* do nothing */;
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// switch back to Device 0
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outb(0x1F6, 0xE0 | (0<<4));
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cprintf("Device 1 presence: %d\n", (x < 1000));
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return (x < 1000);
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}
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void
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ide_set_disk(int d)
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{
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if (d != 0 && d != 1)
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panic("bad disk number");
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diskno = d;
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}
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int
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ide_read(uint32_t secno, void *dst, size_t nsecs)
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{
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int r;
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assert(nsecs <= 256);
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ide_wait_ready(0);
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outb(0x1F2, nsecs);
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outb(0x1F3, secno & 0xFF);
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outb(0x1F4, (secno >> 8) & 0xFF);
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outb(0x1F5, (secno >> 16) & 0xFF);
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outb(0x1F6, 0xE0 | ((diskno&1)<<4) | ((secno>>24)&0x0F));
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outb(0x1F7, 0x20); // CMD 0x20 means read sector
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for (; nsecs > 0; nsecs--, dst += SECTSIZE) {
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if ((r = ide_wait_ready(1)) < 0)
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return r;
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insl(0x1F0, dst, SECTSIZE/4);
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}
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return 0;
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}
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int
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ide_write(uint32_t secno, const void *src, size_t nsecs)
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{
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int r;
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assert(nsecs <= 256);
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ide_wait_ready(0);
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outb(0x1F2, nsecs);
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outb(0x1F3, secno & 0xFF);
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outb(0x1F4, (secno >> 8) & 0xFF);
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outb(0x1F5, (secno >> 16) & 0xFF);
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outb(0x1F6, 0xE0 | ((diskno&1)<<4) | ((secno>>24)&0x0F));
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outb(0x1F7, 0x30); // CMD 0x30 means write sector
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for (; nsecs > 0; nsecs--, src += SECTSIZE) {
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if ((r = ide_wait_ready(1)) < 0)
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return r;
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outsl(0x1F0, src, SECTSIZE/4);
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}
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return 0;
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}
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