Hello.
Alan Cox wrote:
pata_amd: Program FIFO
From: Alan Cox <alan@xxxxxxxxxxxxxxxxxxx>
With 32bit PIO we can use the posted write buffers, but only for 32bit I/O
cycles. This means we must disable the FIFO for ATAPI where a final 16bit
cycle may occur.
Rework the FIFO logic so that we disable the FIFO then selectively re-enable
it when we set the timings on AMD devices. Also fix a case where we scribbled
on PCI config 0x41 of Nvidia chips when we shouldn't.
Signed-off-by: Alan Cox <alan@xxxxxxxxxxxxxxxxxxx>
[...]
diff --git a/drivers/ata/pata_amd.c b/drivers/ata/pata_amd.c
index 63719ab..c380a4e 100644
--- a/drivers/ata/pata_amd.c
+++ b/drivers/ata/pata_amd.c
[...]
@@ -158,6 +165,40 @@ static int amd_cable_detect(struct ata_port *ap)
}
/**
+ * amd_fifo_setup - set the PIO FIFO for ATA/ATAPI
+ * @ap: ATA interface
+ * @adev: ATA device
+ *
+ * Set the PCI fifo for this device according to the devices present
+ * on the bus at this point in time. We need to turn the post write buffer
+ * off for ATAPI devices as we may need to issue a word sized write to the
+ * device as the final I/O
+ */
+
+static void amd_fifo_setup(struct ata_port *ap)
+{
+ struct ata_device *adev;
+ struct pci_dev *pdev = to_pci_dev(ap->host->dev);
+ static const u8 fifobit[2] = { 0xC0, 0x30};
+ u8 fifo = fifobit[ap->port_no];
+ u8 r;
+
+
+ ata_for_each_dev(adev, &ap->link, ENABLED) {
+ if (adev->class == ATA_DEV_ATAPI)
+ fifo = 0;
+ }
Er, couldn't we do that dynamically, based on which device is
executing the command now?
+ if (pdev->device == PCI_DEVICE_ID_AMD_VIPER_7411) /* FIFO is broken */
+ fifo = 0;
+
+ /* On the later chips the read prefetch bits become no-op bits */
+ pci_read_config_byte(pdev, 0x41, &r);
+ r &= ~fifobit[ap->port_no];
Why not:
r &= ~fifo;
+ r |= fifo;
+ pci_write_config_byte(pdev, 0x41, r);
+}
MBR, Sergei
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