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ahci: update PCS programming 

For intel ones, ahci unconditionally OR'd 0xf to PCS.  This isn't
correct for the following cases.

* ich6/7m's which only implement P0 and P2 (0xf works fine tho)

* ich8/9's which have six ports and needs 0x3f to enable all ports

This patch updates PCS programming such that...

* port_map determined by ahci_save_initial_config() is OR'd instead of 0xf

* PCS is updated only if necessary (there are turned off enable bits)

port_map is determined from PORTS_IMPL PCI register which is
implemented as write or write-once register.  If the register isn't
programmed, ahci automatically generates it from number of ports,
which is good enough for PCS programming.  ICH6/7M are probably the
only ones where non-contiguous enable bits are necessary && PORTS_IMPL
isn't programmed properly but they're proven to work reliably with 0xf
anyway.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
This commit is contained in:
Tejun Heo 2007-11-19 16:03:44 +09:00 committed by Jeff Garzik
parent 51dbd49061
commit 49f2909039
1 changed files with 5 additions and 2 deletions
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7
drivers/ata/ahci.c
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@ -1036,6 +1036,7 @@ static int ahci_deinit_port(struct ata_port *ap, const char **emsg)
static int ahci_reset_controller(struct ata_host *host)
{
struct pci_dev *pdev = to_pci_dev(host->dev);
struct ahci_host_priv *hpriv = host->private_data;
void __iomem *mmio = host->iomap[AHCI_PCI_BAR];
u32 tmp;
@ -1078,8 +1079,10 @@ static int ahci_reset_controller(struct ata_host *host)
/* configure PCS */
pci_read_config_word(pdev, 0x92, &tmp16);
tmp16 |= 0xf;
pci_write_config_word(pdev, 0x92, tmp16);
if ((tmp16 & hpriv->port_map) != hpriv->port_map) {
tmp16 |= hpriv->port_map;
pci_write_config_word(pdev, 0x92, tmp16);
}
}
return 0;