libata: fix ata_acpi_gtm_xfermask()

unsigned long ata_acpi_gtm_xfermask(struct ata_device *dev,

				    const struct ata_acpi_gtm *gtm)

{

	unsigned long pio_mask = 0, mwdma_mask = 0, udma_mask = 0;

	int unit, i;

	u32 t;

	unsigned long mask = (0x7f << ATA_SHIFT_UDMA) | (0x7 << ATA_SHIFT_MWDMA) | (0x1F << ATA_SHIFT_PIO);

	/* we always use the 0 slot for crap hardware */

	unit = dev->devno;

	if (!(gtm->flags & 0x10))

		unit = 0;

	/* Values larger than the longest cycle results in 0 mask

	 * while values equal to smaller than the shortest cycle

	 * results in mask which includes all supported modes.

	 * Disabled transfer method has the value of 0xffffffff which

	 * will always result in 0 mask.

	 */

	/* start by scanning for PIO modes */

	for (i = 0; i < 7; i++) {

	t = gtm->drive[unit].pio;

		if (t <= ata_acpi_pio_cycle[i]) {

			mask |= (2 << (ATA_SHIFT_PIO + i)) - 1;

	for (i = 0; i < ARRAY_SIZE(ata_acpi_pio_cycle); i++)

		if (t > ata_acpi_pio_cycle[i])

			break;

		}

	}

	pio_mask = (1 << i) - 1;

	/* See if we have MWDMA or UDMA data. We don't bother with

	 * MWDMA if UDMA is available as this means the BIOS set UDMA

	 * and our error changedown if it works is UDMA to PIO anyway.

	 */

	if (gtm->flags & (1 << (2 * unit))) {

		/* MWDMA */

		for (i = 0; i < 5; i++) {

	t = gtm->drive[unit].dma;

			if (t <= ata_acpi_mwdma_cycle[i]) {

				mask |= (2 << (ATA_SHIFT_MWDMA + i)) - 1;

	if (!(gtm->flags & (1 << (2 * unit)))) {

		/* MWDMA */

		for (i = 0; i < ARRAY_SIZE(ata_acpi_mwdma_cycle); i++)

			if (t > ata_acpi_mwdma_cycle[i])

				break;

			}

		}

		mwdma_mask = (1 << i) - 1;

	} else {

		/* UDMA */

		for (i = 0; i < 7; i++) {

			t = gtm->drive[unit].dma;

			if (t <= ata_acpi_udma_cycle[i]) {

				mask |= (2 << (ATA_SHIFT_UDMA + i)) - 1;

		for (i = 0; i < ARRAY_SIZE(ata_acpi_udma_cycle); i++)

			if (t > ata_acpi_udma_cycle[i])

				break;

			}

		}

		udma_mask = (1 << i) - 1;

	}

	return mask;

	return ata_pack_xfermask(pio_mask, mwdma_mask, udma_mask);

}

EXPORT_SYMBOL_GPL(ata_acpi_gtm_xfermask);