Patchwork [1/2] sata_via: Correctly setup PIO/DMA for pata slave on vt6421.

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Submitter Bart Hartgers
Date Jan. 16, 2010, 11:56 p.m.
Message ID <20100116235849.969478053@gmail.com>
Download mbox | patch
Permalink /patch/43018/
State Not Applicable
Delegated to: David Miller
Headers show

Comments

Bart Hartgers - Jan. 16, 2010, 11:56 p.m.
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
Tejun Heo - Jan. 20, 2010, 3:33 a.m.
On 01/17/2010 08:56 AM, Bart Hartgers wrote:
> 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: Bart Hartgers <bart.hartgers@gmail.com>

Acked-by: Tejun Heo <tj@kernel.org>

Thanks.
Jeff Garzik - Jan. 20, 2010, 7:35 p.m.
On 01/16/2010 06:56 PM, Bart Hartgers wrote:
> 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: Bart Hartgers<bart.hartgers@gmail.com>

applied


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Patch

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: Bart Hartgers <bart.hartgers@gmail.com>
---
Index: linux-2.6.33-rc4/drivers/ata/sata_via.c
===================================================================
--- linux-2.6.33-rc4.orig/drivers/ata/sata_via.c	2010-01-16 22:28:13.000000000 +0100
+++ linux-2.6.33-rc4/drivers/ata/sata_via.c	2010-01-16 22:29:30.000000000 +0100
@@ -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 a
 {
 	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[] = {