audk/OvmfPkg/SataControllerDxe
Laszlo Ersek bcab714134 OvmfPkg: SataControllerDxe: enable IO / mem access and DMA when binding
When we bind the SATA controller in SataControllerStart(), we read the NP
("Number of Ports") bitfield from the CAP ("HBA Capabilities") register of
the controller. (See the AHCI 1.3.1 spec.)

This register is memory mapped. If we'd like to access it, we must at
least enable memory space access for the device. In addition, Feng Tian
recommended enabling Bus Master DMA in
<http://thread.gmane.org/gmane.comp.bios.tianocore.devel/10545/focus=10659>.
We also enable IO space access for completeness.

Further, because we change the PCI attributes of the device with the above
when binding it, we must also restore its original PCI attributes when
unbinding it. See the Driver Writer's Guide for UEFI 2.3.1 v1.01, section
18.3 "PCI drivers" | 18.3.2 "Start() and Stop()".

(OvmfPkg's copy of SataControllerDxe differs from the same in DuetPkg
because Duet inherits a pre-configured SATA controller from the BIOS, as
explained by Feng. Technically, DuetPkg's SataControllerDxe could also
apply the technique seen in this patch.)

Cc: Alexander Graf <agraf@suse.de>
Cc: Reza Jelveh <reza.jelveh@tuhh.de>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Gabriel L. Somlo <somlo@cmu.edu>
Cc: Feng Tian <feng.tian@intel.com>
Suggested-by: Feng Tian <feng.tian@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Feng Tian <feng.tian@intel.com>
Tested-by: Gabriel Somlo <somlo@cmu.edu>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18528 6f19259b-4bc3-4df7-8a09-765794883524
2015-09-22 11:18:27 +00:00
..
ComponentName.c
SataController.c OvmfPkg: SataControllerDxe: enable IO / mem access and DMA when binding 2015-09-22 11:18:27 +00:00
SataController.h OvmfPkg: SataControllerDxe: enable IO / mem access and DMA when binding 2015-09-22 11:18:27 +00:00
SataControllerDxe.inf