DCA: Add Direct Cache Access driver

Direct Cache Access (DCA) is a method for warming the CPU cache before data
is used, with the intent of lessening the impact of cache misses.  This
patch adds a manager and interface for matching up client requests for DCA
services with devices that offer DCA services.

In order to use DCA, a module must do bus writes with the appropriate tag
bits set to trigger a cache read for a specific CPU.  However, different
CPUs and chipsets can require different sets of tag bits, and the methods
for determining the correct bits may be simple hardcoding or may be a
hardware specific magic incantation.  This interface is a way for DCA
clients to find the correct tag bits for the targeted CPU without needing
to know the specifics.

    [Dave Miller] use DEFINE_SPINLOCK()

Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/Kconfig b/drivers/Kconfig
index 7bdae47d6b9..4fb134d50da 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -84,6 +84,8 @@ source "drivers/rtc/Kconfig"
 
 source "drivers/dma/Kconfig"
 
+source "drivers/dca/Kconfig"
+
 source "drivers/auxdisplay/Kconfig"
 
 source "drivers/kvm/Kconfig"