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authorGabe Black <gabeblack@google.com>2013-09-30 23:00:33 -0700
committerIsaac Christensen <isaac.christensen@se-eng.com>2014-09-08 18:59:23 +0200
commit51edd54738b2248e92580caa317aa4e8e1694d40 (patch)
treed10c6be921f2d3656d9f504f4572a1c73f7860e3 /src/arch/arm/stages.c
parent94b4a266fb4df1f2f59ed8052c150ee4bf3e6d41 (diff)
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ARM: Generalize armv7 as arm.
There are ARM systems which are essentially heterogeneous multicores where some cores implement a different ARM architecture version than other cores. A specific example is the tegra124 which boots on an ARMv4 coprocessor while most code, including most of the firmware, runs on the main ARMv7 core. To support SOCs like this, the plan is to generalize the ARM architecture so that all versions are available, and an SOC/CPU can then select what architecture variant should be used for each component of the firmware; bootblock, romstage, and ramstage. Old-Change-Id: I22e048c3bc72bd56371e14200942e436c1e312c2 Signed-off-by: Gabe Black <gabeblack@google.com> Reviewed-on: https://chromium-review.googlesource.com/171338 Reviewed-by: Gabe Black <gabeblack@chromium.org> Commit-Queue: Gabe Black <gabeblack@chromium.org> Tested-by: Gabe Black <gabeblack@chromium.org> (cherry picked from commit 8423a41529da0ff67fb9873be1e2beb30b09ae2d) Signed-off-by: Isaac Christensen <isaac.christensen@se-eng.com> ARM: Split out ARMv7 code and make it possible to have other arch versions. We don't always want to use ARMv7 code when building for ARM, so we should separate out the ARMv7 code so it can be excluded, and also make it possible to include code for some other version of the architecture instead, all per build component for cases where we need more than one architecture version at a time. The tegra124 bootblock will ultimately need to be ARMv4, but until we have some ARMv4 code to switch over to we can leave it set to ARMv7. Old-Change-Id: Ia982c91057fac9c252397b7c866224f103761cc7 Reviewed-on: https://chromium-review.googlesource.com/171400 Reviewed-by: Gabe Black <gabeblack@chromium.org> Tested-by: Gabe Black <gabeblack@chromium.org> Commit-Queue: Gabe Black <gabeblack@chromium.org> (cherry picked from commit 799514e6060aa97acdcf081b5c48f965be134483) Squashed two related patches for splitting ARM support into general ARM support and ARMv7 specific pieces. Change-Id: Ic6511507953a2223c87c55f90252c4a4e1dd6010 Signed-off-by: Isaac Christensen <isaac.christensen@se-eng.com> Reviewed-on: http://review.coreboot.org/6782 Tested-by: build bot (Jenkins)
Diffstat (limited to 'src/arch/arm/stages.c')
-rw-r--r--src/arch/arm/stages.c61
1 files changed, 61 insertions, 0 deletions
diff --git a/src/arch/arm/stages.c b/src/arch/arm/stages.c
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+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2012 Google Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/*
+ * This file contains entry/exit functions for each stage during coreboot
+ * execution (bootblock entry and ramstage exit will depend on external
+ * loading.
+ *
+ * Unlike other files, this one should be compiled with a -m option to
+ * specify a pre-determined instruction set. This is to ensure consistency
+ * in the CPU operating mode (ARM or Thumb) when hand-off between stages
+ * occurs.
+ *
+ * Entry points must be placed at the location the previous stage jumps
+ * to (the lowest address in the stage image). This is done by giving
+ * stage_entry() its own section in .text and placing it first in the
+ * linker script.
+ */
+
+#include <arch/stages.h>
+#include <arch/cache.h>
+
+void stage_entry(void)
+{
+ main();
+}
+
+/* we had marked 'doit' as 'noreturn'.
+ * There is no apparent harm in leaving it as something we can return from, and in the one
+ * case where we call a payload, the payload is allowed to return.
+ * Hence, leave it as something we can return from.
+ */
+void stage_exit(void *addr)
+{
+ void (*doit)(void) = addr;
+ /* make sure any code we installed is written to memory. Not all ARM have
+ * unified caches.
+ */
+ dcache_clean_all();
+ /* Because most stages copy code to memory, it's a safe and hygienic thing
+ * to flush the icache here.
+ */
+ icache_invalidate_all();
+ doit();
+}