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authorThiemo Seufer <ths@networkno.de>2005-04-25 16:36:23 +0000
committerRalf Baechle <ralf@linux-mips.org>2005-10-29 19:31:11 +0100
commitba5187dbb4b2eac99d6fa1d6bbece67e0066bf51 (patch)
tree9a1fa0b0cb6ff1c64c20569c4e6ecdfd3f865bbc /arch/mips/lib/uncached.c
parent7de8d2328767cf4cb463dd3ca70c44985ac835a8 (diff)
Better interface to run uncached cache setup code.
Signed-off-by: Thiemo Seufer <ths@networkno.de> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips/lib/uncached.c')
-rw-r--r--arch/mips/lib/uncached.c76
1 files changed, 76 insertions, 0 deletions
diff --git a/arch/mips/lib/uncached.c b/arch/mips/lib/uncached.c
new file mode 100644
index 00000000000..98ce89f8068
--- /dev/null
+++ b/arch/mips/lib/uncached.c
@@ -0,0 +1,76 @@
+/*
+ * 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) 2005 Thiemo Seufer
+ * Copyright (C) 2005 MIPS Technologies, Inc. All rights reserved.
+ * Author: Maciej W. Rozycki <macro@mips.com>
+ */
+
+#include <linux/init.h>
+
+#include <asm/addrspace.h>
+#include <asm/bug.h>
+
+#ifndef CKSEG2
+#define CKSEG2 CKSSEG
+#endif
+#ifndef TO_PHYS_MASK
+#define TO_PHYS_MASK -1
+#endif
+
+/*
+ * FUNC is executed in one of the uncached segments, depending on its
+ * original address as follows:
+ *
+ * 1. If the original address is in CKSEG0 or CKSEG1, then the uncached
+ * segment used is CKSEG1.
+ * 2. If the original address is in XKPHYS, then the uncached segment
+ * used is XKPHYS(2).
+ * 3. Otherwise it's a bug.
+ *
+ * The same remapping is done with the stack pointer. Stack handling
+ * works because we don't handle stack arguments or more complex return
+ * values, so we can avoid sharing the same stack area between a cached
+ * and the uncached mode.
+ */
+unsigned long __init run_uncached(void *func)
+{
+ register long sp __asm__("$sp");
+ register long ret __asm__("$2");
+ long lfunc = (long)func, ufunc;
+ long usp;
+
+ if (sp >= (long)CKSEG0 && sp < (long)CKSEG2)
+ usp = CKSEG1ADDR(sp);
+ else if ((long long)sp >= (long long)PHYS_TO_XKPHYS(0LL, 0) &&
+ (long long)sp < (long long)PHYS_TO_XKPHYS(8LL, 0))
+ usp = PHYS_TO_XKPHYS((long long)K_CALG_UNCACHED,
+ XKPHYS_TO_PHYS((long long)sp));
+ else {
+ BUG();
+ usp = sp;
+ }
+ if (lfunc >= (long)CKSEG0 && lfunc < (long)CKSEG2)
+ ufunc = CKSEG1ADDR(lfunc);
+ else if ((long long)lfunc >= (long long)PHYS_TO_XKPHYS(0LL, 0) &&
+ (long long)lfunc < (long long)PHYS_TO_XKPHYS(8LL, 0))
+ ufunc = PHYS_TO_XKPHYS((long long)K_CALG_UNCACHED,
+ XKPHYS_TO_PHYS((long long)lfunc));
+ else {
+ BUG();
+ ufunc = lfunc;
+ }
+
+ __asm__ __volatile__ (
+ " move $16, $sp\n"
+ " move $sp, %1\n"
+ " jalr %2\n"
+ " move $sp, $16"
+ : "=r" (ret)
+ : "r" (usp), "r" (ufunc)
+ : "$16", "$31");
+
+ return ret;
+}