Problem with reading from ata[solved]
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Author:  Klakap [ Sat Feb 09, 2019 10:59 am ]
Post subject:  Re: Problem with reading from ata[solved]

Thank you! I found than qemu is stuck only after write. I can read everything, but after write some sector, next read command stuck on while. I dont now what is acknowledge the interrupt by reading from the status register. I read status register in pooling. Please what is it?

Author:  BenLunt [ Mon Feb 11, 2019 11:29 am ]
Post subject:  Re: Problem with reading from ata[solved]

Acknowledge the interrupt by reading from the ATA_STATUS register. Other times you should be reading from the ALT_ATA_STATUS register.

Also, please note that if the busy bit is set, all other bits are considered undefined. You need to make sure the busy bit is clear before you check the DRQ bit.

As for why you are having issues after a write, I cannot tell you why without looking at all you code. It could be anything.

- http://www.fysnet.net/osdesign_book_series.htm

Author:  Klakap [ Mon Feb 11, 2019 1:07 pm ]
Post subject:  Re: Problem with reading from ata[solved]

Thank you for answer, I write while for busy. My code is:
#define ATA_PORT_DATA 0x000
#define ATA_PORT_ERROR 0x001
#define ATA_PORT_FEATURES 0x001
#define ATA_PORT_SCT_COUNT 0x002
#define ATA_PORT_SCT_NUMBER 0x003
#define ATA_PORT_CYL_LOW 0x004
#define ATA_PORT_CYL_HIGH 0x005
#define ATA_PORT_DRV 0x006
#define ATA_PORT_STATUS 0x007
#define ATA_PORT_COMMAND 0x007

uint16_t buffer[256];

void ata_pio28(uint16_t base, uint8_t type, uint64_t addr, uint8_t drive) {
    if(drive==ATA_MASTER) {
    outb(base+ATA_PORT_DRV, 0xE0);
    else { // ATA_SLAVE
    outb(base+ATA_PORT_DRV, 0xF0);

    if ((inb(base+ATA_PORT_STATUS) & 0x01)) {

    outb(base+ATA_PORT_FEATURES, 0x00);
    outb(base+ATA_PORT_SCT_COUNT, 0x01);
    outb(base+ATA_PORT_SCT_NUMBER, (unsigned char)addr);
    outb(base+ATA_PORT_CYL_LOW, (unsigned char)(addr >> 8));
    outb(base+ATA_PORT_CYL_HIGH, (unsigned char)(addr >> 16));
    if(type==ATA_READ) {
    outb(base+ATA_PORT_COMMAND, 0x20);  // Send command
    else {
    outb(base+ATA_PORT_COMMAND, 0x30);

    while (!(inb(base+ATA_PORT_STATUS) & 0x80)) {}  //BSY bit
    while (!(inb(base+ATA_PORT_STATUS) & 0x08)) {}  //DRQ bit

    for (int idx = 0; idx < 256; idx++)
        if(type==ATA_READ) {
            buffer[idx] = inw(base + ATA_PORT_DATA);
        else {
            outw(base + ATA_PORT_DATA, buffer[idx]);


Hard disc is in Primary Master.

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