xhci: Workaround to get D3 working in Intel xHCI

[ Upstream commit abce329c27 ]

The xHCI in Intel CherryView / Braswell Platform requires
a driver workaround to get xHCI D3 working. Without this
workaround, xHCI might not enter D3.

Workaround is to configure SSIC PORT as "unused" before D3
entry and "used" after D3 exit. This is done through a
vendor specific register (PORT2_SSIC_CONFIG_REG2 at offset
0x883c), in xhci suspend / resume callbacks.

Verified xHCI D3 works fine in CherryView / Braswell platform.

Signed-off-by: Rajmohan Mani <rajmohan.mani@intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
This commit is contained in:
Rajmohan Mani 2015-07-21 17:20:26 +03:00 • committed by Sasha Levin
commit a587e280cb