tree 93e98e81a7d359c679ce081295d939be948c1c80
parent 51dbd490614e6228e9b2b198bd4f5f76ef961059
author Tejun Heo <htejun@gmail.com> 1195455824 +0900
committer Jeff Garzik <jeff@garzik.org> 1201083850 -0500

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>