Why does AHCI Command Engine is still running?

[gamingjam60]

Here my runCommand function

Code: Select all

static bool runCommand(FIS_TYPE type, uint8_t write, HBA_PORT_T *port, uint32_t start_l, uint32_t start_h, uint32_t count, uint16_t* buf)
{
    // Clear pending interrupt bits
	port->is = (uint32_t) -1;		
    // Spin lock timeout counter
	int spin = 0; 
	int slot = findCMDSlot(port, 32);

	if (slot == -1)
		return false;
 
	HBA_CMD_HEADER_T* cmd_header = (HBA_CMD_HEADER_T*) phys_to_vir((uint64_t) port->clb);

	cmd_header += slot;
    // Command FIS size
	cmd_header->cfl = sizeof(FIS_REG_H2D_T) / sizeof(uint32_t);	
	// Read or write from device
    cmd_header->w = write;
    // PRDT entries count
	cmd_header->prdtl = (uint16_t) ((count - 1) >> 4) + 1;	
 
	HBA_CMD_TBL_T* cmd_tbl = (HBA_CMD_TBL_T*) phys_to_vir((uint64_t) (cmd_header->ctba));
	memset((void *)cmd_tbl, 0, sizeof(HBA_CMD_TBL_T) + (cmd_header->prdtl - 1) * sizeof(HBA_PRDT_ENTRY_T));
 
	// 8K bytes (16 sectors) per PRDT
    uint16_t i;
	for (i = 0; i < cmd_header->prdtl - 1; i++)
	{
		cmd_tbl->prdt_entry[i].dba = (uint32_t)((uint64_t)buf);
        // 8K bytes (this value should always be set to 1 less than the actual value)
		cmd_tbl->prdt_entry[i].dbc = 8 * 1024 - 1;	
		cmd_tbl->prdt_entry[i].i = 1;
        // 4K words
		buf += 4 * 1024;	
        // 16 sectors
		count -= 16;	
	}


	// Last entry
	cmd_tbl->prdt_entry[i].dba = (uint32_t) buf;

    // 512 bytes per sector
	cmd_tbl->prdt_entry[i].dbc = (count << 9) - 1;	
	cmd_tbl->prdt_entry[i].i = 1;
 
	// Setup command
	FIS_REG_H2D_T* cmd_fis = (FIS_REG_H2D_T*) (&cmd_tbl->cfis);
	cmd_fis->fis_type = FIS_TYPE_REG_H2D;

    // Command
	cmd_fis->c = 1;	
	cmd_fis->command = type;

 	// LBA mode
	cmd_fis->lba0 = (uint8_t) start_l;
	cmd_fis->lba1 = (uint8_t) (start_l >> 8);
	cmd_fis->lba2 = (uint8_t) (start_l >> 16);
	cmd_fis->device = 1 << 6;
 
	cmd_fis->lba3 = (uint8_t) (start_l >> 24);
	cmd_fis->lba4 = (uint8_t) start_h;
	cmd_fis->lba5 = (uint8_t) (start_h >> 8);
 
	cmd_fis->countl = count & 0xFF;
	cmd_fis->counth = (count >> 8) & 0xFF;
 
	// The below loop waits until the port is no longer busy before issuing a new command
	while ((port->tfd & (ATA_DEV_BUSY | ATA_DEV_DRQ)) && spin < 1000000)
	{
		spin++;
	}

	if (spin == 1000000)
	{
		printf(" [-] AHCI: Port is hung\n");
		return false;
	}

    // Issue command
	port->ci = 1 << slot;	
 
	// Wait for completion
	while (true)
	{
		// In some longer duration reads, it may be helpful to spin on the DPS bit 
		// in the PxIS port field as well (1 << 5)
		if (!(port->ci & (1 << slot)))
			break;

        // Task file error
		if (port->is & HBA_PxIS_TFES)	
		{
			printf(" [-] AHCI: Read disk error\n");
			return false;
		}
		printf("!(port->ci & (1 << slot)): %b, port->is & HBA_PxIS_TFES: %b\n",
			!(port->ci & (1 << slot)), port->is & HBA_PxIS_TFES);
	}

	// Check again
	if (port->is & HBA_PxIS_TFES)
	{
		printf(" [-] AHCI: Read disk error\n");
		return false;
	}
 
	return true;
}

The output is showing while loop never break as !(port->ci & (1 << slot)) = 0 and port->is & HBA_PxIS_TFES = 0

The full code ahci.c and ahci.h

How can I resolve the issue present in here?Please Help!

[Octocontrabass]

Look at figure 4 on page 36 of the AHCI specification. All of the data structures listed on the right side of that figure need to be located in RAM. You can't put them inside the ABAR MMIO.

[gamingjam60]

Thankyou