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authorMax Filippov <jcmvbkbc@gmail.com>2012-11-19 07:00:41 +0400
committerChris Zankel <chris@zankel.net>2012-12-18 21:10:22 -0800
commitc622b29d1f38021411965b7e0170ab055551b257 (patch)
treef86875612ade331965b80abafb14cbd796924461 /arch/xtensa
parent733536b865441d9bad02c4711a4372d48ce21e54 (diff)
downloadop-kernel-dev-c622b29d1f38021411965b7e0170ab055551b257.zip
op-kernel-dev-c622b29d1f38021411965b7e0170ab055551b257.tar.gz
xtensa: initialize atomctl SR
In order to use S32C1I instruction on cores with ATOMCTL SR the register must be properly initialized. Signed-off-by: Max Filippov <jcmvbkbc@gmail.com> Signed-off-by: Chris Zankel <chris@zankel.net>
Diffstat (limited to 'arch/xtensa')
-rw-r--r--arch/xtensa/include/asm/initialize_mmu.h55
-rw-r--r--arch/xtensa/kernel/head.S3
2 files changed, 58 insertions, 0 deletions
diff --git a/arch/xtensa/include/asm/initialize_mmu.h b/arch/xtensa/include/asm/initialize_mmu.h
new file mode 100644
index 0000000..e1f8ba4
--- /dev/null
+++ b/arch/xtensa/include/asm/initialize_mmu.h
@@ -0,0 +1,55 @@
+/*
+ * arch/xtensa/include/asm/initialize_mmu.h
+ *
+ * Initializes MMU:
+ *
+ * For the new V3 MMU we remap the TLB from virtual == physical
+ * to the standard Linux mapping used in earlier MMU's.
+ *
+ * The the MMU we also support a new configuration register that
+ * specifies how the S32C1I instruction operates with the cache
+ * controller.
+ *
+ * This file is subject to the terms and conditions of the GNU General
+ * Public License. See the file "COPYING" in the main directory of
+ * this archive for more details.
+ *
+ * Copyright (C) 2008 - 2012 Tensilica, Inc.
+ *
+ * Marc Gauthier <marc@tensilica.com>
+ * Pete Delaney <piet@tensilica.com>
+ */
+
+#ifndef _XTENSA_INITIALIZE_MMU_H
+#define _XTENSA_INITIALIZE_MMU_H
+
+#ifdef __ASSEMBLY__
+
+#define XTENSA_HWVERSION_RC_2009_0 230000
+
+ .macro initialize_mmu
+
+#if XCHAL_HAVE_S32C1I && (XCHAL_HW_MIN_VERSION >= XTENSA_HWVERSION_RC_2009_0)
+/*
+ * We Have Atomic Operation Control (ATOMCTL) Register; Initialize it.
+ * For details see Documentation/xtensa/atomctl.txt
+ */
+#if XCHAL_DCACHE_IS_COHERENT
+ movi a3, 0x25 /* For SMP/MX -- internal for writeback,
+ * RCW otherwise
+ */
+#else
+ movi a3, 0x29 /* non-MX -- Most cores use Std Memory
+ * Controlers which usually can't use RCW
+ */
+#endif
+ wsr a3, atomctl
+#endif /* XCHAL_HAVE_S32C1I &&
+ * (XCHAL_HW_MIN_VERSION >= XTENSA_HWVERSION_RC_2009_0)
+ */
+
+ .endm
+
+#endif /*__ASSEMBLY__*/
+
+#endif /* _XTENSA_INITIALIZE_MMU_H */
diff --git a/arch/xtensa/kernel/head.S b/arch/xtensa/kernel/head.S
index 417998c..9013ae0 100644
--- a/arch/xtensa/kernel/head.S
+++ b/arch/xtensa/kernel/head.S
@@ -18,6 +18,7 @@
#include <asm/processor.h>
#include <asm/page.h>
#include <asm/cacheasm.h>
+#include <asm/initialize_mmu.h>
#include <linux/init.h>
#include <linux/linkage.h>
@@ -155,6 +156,8 @@ ENTRY(_startup)
isync
+ initialize_mmu
+
/* Unpack data sections
*
* The linker script used to build the Linux kernel image
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