Optimize Cortex-A57 cluster power down sequence on Juno

This patch optimizes the Cortex-A57 cluster power down sequence by not
flushing the Level1 data cache. The L1 data cache and the L2 unified
cache are inclusive. A flush of the L2 by set/way flushes any dirty
lines from the L1 as well. This is a known safe deviation from the
Cortex-A57 TRM defined power down sequence. This optimization can be
enabled by the platform through the 'SKIP_A57_L1_FLUSH_PWR_DWN' build
flag. Each Cortex-A57 based platform must make its own decision on
whether to use the optimization.

This patch also renames the cpu-errata-workarounds.md to
cpu-specific-build-macros.md as this facilitates documentation
of both CPU Specific errata and CPU Specific Optimization
build macros.

Change-Id: I299b9fe79e9a7e08e8a0dffb7d345f9a00a71480

1 files changed, 57 insertions, 0 deletions

diff --git a/lib/cpus/cpu-ops.mk b/lib/cpus/cpu-ops.mk
new file mode 100644
index 000000000..1c5512e9c
--- /dev/null
+++ b/lib/cpus/cpu-ops.mk
@@ -0,0 +1,57 @@
+#
+# Copyright (c) 2014, ARM Limited and Contributors. All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# Redistributions of source code must retain the above copyright notice, this
+# list of conditions and the following disclaimer.
+#
+# Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# Neither the name of ARM nor the names of its contributors may be used
+# to endorse or promote products derived from this software without specific
+# prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+#
+
+# Cortex A57 specific optimisation to skip L1 cache flush when
+# cluster is powered down.
+SKIP_A57_L1_FLUSH_PWR_DWN	?=0
+
+# Process SKIP_A57_L1_FLUSH_PWR_DWN flag
+$(eval $(call assert_boolean,SKIP_A57_L1_FLUSH_PWR_DWN))
+$(eval $(call add_define,SKIP_A57_L1_FLUSH_PWR_DWN))
+
+
+# CPU Errata Build flags. These should be enabled by the
+# platform if the errata needs to be applied.
+
+# Flag to apply errata 806969 during reset. This errata applies only to
+# revision r0p0 of the Cortex A57 cpu.
+ERRATA_A57_806969	?=0
+
+# Flag to apply errata 813420 during reset. This errata applies only to
+# revision r0p0 of the Cortex A57 cpu.
+ERRATA_A57_813420	?=0
+
+# Process ERRATA_A57_806969 flag
+$(eval $(call assert_boolean,ERRATA_A57_806969))
+$(eval $(call add_define,ERRATA_A57_806969))
+
+# Process ERRATA_A57_813420 flag
+$(eval $(call assert_boolean,ERRATA_A57_813420))
+$(eval $(call add_define,ERRATA_A57_813420))