Commit d33d44fa authored by Alan Cox's avatar Alan Cox Committed by Jeff Garzik
Browse files

[PATCH] libata: two new PCI helpers 



The first performs the simplex clearing relevant to some chipsets that
report simplex by default but can in fact do more if poked. The second
is used to strip DMA modes from a PCI control with no BAR4 allocation.

Signed-off-by: default avatarJeff Garzik <jeff@garzik.org>
parent 41bbc8bf

drivers/scsi/libata-bmdma.c

+36 −0
Original line number Diff line number Diff line
@@ -700,5 +700,41 @@ err_out: 
	return rc;

}



/**

 *	ata_pci_clear_simplex	-	attempt to kick device out of simplex

 *	@pdev: PCI device

 *

 *	Some PCI ATA devices report simplex mode but in fact can be told to

 *	enter non simplex mode. This implements the neccessary logic to 

 *	perform the task on such devices. Calling it on other devices will

 *	have -undefined- behaviour.

 */



int ata_pci_clear_simplex(struct pci_dev *pdev)

{

	unsigned long bmdma = pci_resource_start(pdev, 4);

	u8 simplex;



	if (bmdma == 0)

		return -ENOENT;



	simplex = inb(bmdma + 0x02);

	outb(simplex & 0x60, bmdma + 0x02);

	simplex = inb(bmdma + 0x02);

	if (simplex & 0x80)

		return -EOPNOTSUPP;

	return 0;

}



unsigned long ata_pci_default_filter(const struct ata_port *ap, struct ata_device *adev, unsigned long xfer_mask)

{

	/* Filter out DMA modes if the device has been configured by

	   the BIOS as PIO only */

	   

	if (ap->ioaddr.bmdma_addr == 0)

		xfer_mask &= ~(ATA_MASK_MWDMA | ATA_MASK_UDMA);

	return xfer_mask;

}



#endif /* CONFIG_PCI */

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