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Commit 02d1d616 authored by Bart Hartgers's avatar Bart Hartgers Committed by Jeff Garzik
Browse files

sata_via: Correctly setup PIO/DMA for pata slave on vt6421. 

Before only the timings for master were set. Datasheet can be found
here: ftp://ftp.vtbridge.org/Docs/Storage/DS_VT6421A_100_CCPL.PDF


Surprisingly, a slave drive works without this patch. According to the
datasheet, the controller by default derives the DMA mode from the
Set Features command issued to a drive. Not sure about the PIO
timings, though. The real problem is that the timings for the master
effectively are the ones tuned for the slave. If these support
different UDMA-settings, there is trouble, especially when the slave
supports a higher UDMA than the master.

Anyhow, using the same mechanism for both master and slave seems like
a good idea.

Signed-off-by: default avatarBart Hartgers <bart.hartgers@gmail.com>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarJeff Garzik <jgarzik@redhat.com>
parent 9ffc5da5

drivers/ata/sata_via.c

+5 −3
Original line number Diff line number Diff line
@@ -44,7 +44,7 @@ 
#include <linux/libata.h>



#define DRV_NAME	"sata_via"

#define DRV_VERSION	"2.4"

#define DRV_VERSION	"2.5"



/*

 * vt8251 is different from other sata controllers of VIA.  It has two
@@ -392,14 +392,16 @@ static void vt6421_set_pio_mode(struct ata_port *ap, struct ata_device *adev) 
{

	struct pci_dev *pdev = to_pci_dev(ap->host->dev);

	static const u8 pio_bits[] = { 0xA8, 0x65, 0x65, 0x31, 0x20 };

	pci_write_config_byte(pdev, PATA_PIO_TIMING, pio_bits[adev->pio_mode - XFER_PIO_0]);

	pci_write_config_byte(pdev, PATA_PIO_TIMING - adev->devno,

			      pio_bits[adev->pio_mode - XFER_PIO_0]);

}



static void vt6421_set_dma_mode(struct ata_port *ap, struct ata_device *adev)

{

	struct pci_dev *pdev = to_pci_dev(ap->host->dev);

	static const u8 udma_bits[] = { 0xEE, 0xE8, 0xE6, 0xE4, 0xE2, 0xE1, 0xE0, 0xE0 };

	pci_write_config_byte(pdev, PATA_UDMA_TIMING, udma_bits[adev->dma_mode - XFER_UDMA_0]);

	pci_write_config_byte(pdev, PATA_UDMA_TIMING - adev->devno,

			      udma_bits[adev->dma_mode - XFER_UDMA_0]);

}



static const unsigned int svia_bar_sizes[] = {