1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
|
#include <stdint.h>
#include <stddef.h>
#include <stdbool.h>
#include <kernel/fs/ata.h>
#include <kernel/system.h>
#include <kernel/io/io.h>
static uint16_t sel_base_port = 0;
static uint8_t sel_master_or_slave = 0;
static uint32_t max_sector;
static uint8_t read_stat(uint16_t base)
{
inb(base + COM_STAT);
inb(base + COM_STAT);
inb(base + COM_STAT);
inb(base + COM_STAT);
return inb(base + COM_STAT);
}
static void check_drive(uint16_t base, uint8_t master_or_slave)
{
if (sel_base_port != 0)
return;
outb(base + DRIVE_SELECT, master_or_slave);
outb(base + SECTOR_COUNT, 0);
outb(base + LBA_LOW, 0);
outb(base + LBA_MID, 0);
outb(base + LBA_HIGH, 0);
outb(base + COM_STAT, IDENTIFY);
uint8_t stat = read_stat(base);
if (stat == 0)
return;
while ((stat & BSY) != 0)
stat = read_stat(base);
while ((stat & DRQ) == 0 && (stat & ERR) == 0)
stat = read_stat(base);
if ((stat & ERR) != 0)
return;
uint16_t drive_data[256];
for (size_t i = 0; i < 256; i++)
drive_data[i] = inw(base + DATA);
max_sector = drive_data[MAX_28LBA_SECTORS] | drive_data[MAX_28LBA_SECTORS + 1] << 16;
sel_base_port = base;
sel_master_or_slave = master_or_slave;
}
void ata_init()
{
uint8_t pri_status = inb(PRIMARY_BASE + COM_STAT);
uint8_t sec_status = inb(SECONDARY_BASE + COM_STAT);
bool primary_floating = false;
bool secondary_floating = false;
if (pri_status == 0xFF)
primary_floating = true;
if (sec_status == 0xFF)
secondary_floating = true;
if (primary_floating && secondary_floating) {
log("No drives attached! What's going on?");
return;
}
check_drive(PRIMARY_BASE, SEL_MASTER);
check_drive(PRIMARY_BASE, SEL_SLAVE);
check_drive(SECONDARY_BASE, SEL_MASTER);
check_drive(SECONDARY_BASE, SEL_SLAVE);
if (sel_base_port == 0)
log("No drives attached! What's going on?");
else {
log("Found a drive!\nSelected drive is the %s on the %s bus",
sel_master_or_slave == SEL_MASTER ? "master" : "slave",
sel_base_port == PRIMARY_BASE ? "primary" : "secondary");
log("Max LBA value is %d", max_sector);
}
}
static void poll()
{
uint8_t stat;
do
stat = read_stat(sel_base_port);
while ((stat & BSY) != 0);
}
void read_abs_sectors(uint32_t lba, uint8_t sector_count, uint16_t buf[])
{
assert(lba >> LBA_BITS == 0);
outb(sel_base_port + DRIVE_SELECT, (lba >> (LBA_BITS - 4)) | sel_master_or_slave | 1 << 6);
outb(sel_base_port + SECTOR_COUNT, sector_count);
outb(sel_base_port + LBA_LOW, lba & 0xFF);
outb(sel_base_port + LBA_MID, (lba >> 8) & 0xFF);
outb(sel_base_port + LBA_HIGH, (lba >> 16) & 0xFF);
outb(sel_base_port + COM_STAT, READ_SECTORS);
size_t i = 0;
for (; sector_count > 0; sector_count--) {
poll();
asm("rep insw" ::"c"(SECTOR_SIZE / 2), "d"(sel_base_port + DATA), "D"(buf + i));
i += SECTOR_SIZE / 2;
}
}
|
