From 9e83b98a79d25136282a1757f879c40ee929a28b Mon Sep 17 00:00:00 2001
From: Mike Frysinger <michael.frysinger@analog.com>
Date: Wed, 21 Nov 2007 16:08:58 +0800
Subject: [PATCH] Blackfin arch: add support for working around anomaly
05000312
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Anomaly 05000312 - Errors When SSYNC, CSYNC, or Loads to LT, LB and LC Registers Are Interrupted:
DESCRIPTION:
When instruction cache is enabled, erroneous behavior may occur when any of the following instructions are interrupted:
. CSYNC
• SSYNC
• LCx =
• LTx = (only when LCx is non-zero)
• LBx = (only when LCx is non-zero)
When this problem occurs, a variety of incorrect things could happen, including an illegal instruction exception. Additional errors could
show up as an exception, a hardware error, or an instruction that is valid but different than the one that was expected.
WORKAROUND:
Place a cli before all SSYNC, CSYNC, "LCx =", "LTx =", and "LBx =" instructions to disable interrupts, and place an sti after each of these
instructions to re-enable interrupts. When these instructions are executed in code that is already non-interruptible, the problem will not
occur.
Signed-off-by: Mike Frysinger <michael.frysinger@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>
---
include/asm-blackfin/delay.h | 66 +++++++++++++++++++++++-------------
1 file changed, 42 insertions(+), 24 deletions(-)
diff --git a/include/asm-blackfin/delay.h b/include/asm-blackfin/delay.h
index 52e7a10d7ff8..473a8113277f 100644
--- a/include/asm-blackfin/delay.h
+++ b/include/asm-blackfin/delay.h
@@ -1,29 +1,47 @@
-#ifndef _BLACKFIN_DELAY_H
-#define _BLACKFIN_DELAY_H
+/*
+ * delay.h - delay functions
+ *
+ * Copyright (c) 2004-2007 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+#ifndef __ASM_DELAY_H__
+#define __ASM_DELAY_H__
+
+#include <asm/mach/anomaly.h>
static inline void __delay(unsigned long loops)
{
-
-/* FIXME: Currently the assembler doesn't recognize Loop Register Clobbers,
- uncomment this as soon those are implemented */
-/*
- __asm__ __volatile__ ( "\t LSETUP (1f,1f) LC0= %0\n\t"
- "1:\t NOP;\n\t"
- : :"a" (loops)
- : "LT0","LB0","LC0");
-
-*/
-
- __asm__ __volatile__("[--SP] = LC0;\n\t"
- "[--SP] = LT0;\n\t"
- "[--SP] = LB0;\n\t"
- "LSETUP (1f,1f) LC0 = %0;\n\t"
- "1:\t NOP;\n\t"
- "LB0 = [SP++];\n\t"
- "LT0 = [SP++];\n\t"
- "LC0 = [SP++];\n"
- :
- :"a" (loops));
+ if (ANOMALY_05000312) {
+ /* Interrupted loads to loop registers -> bad */
+ unsigned long tmp;
+ __asm__ __volatile__(
+ "[--SP] = LC0;"
+ "[--SP] = LT0;"
+ "[--SP] = LB0;"
+ "LSETUP (1f,1f) LC0 = %1;"
+ "1: NOP;"
+ /* We take advantage of the fact that LC0 is 0 at
+ * the end of the loop. Otherwise we'd need some
+ * NOPs after the CLI here.
+ */
+ "CLI %0;"
+ "LB0 = [SP++];"
+ "LT0 = [SP++];"
+ "LC0 = [SP++];"
+ "STI %0;"
+ : "=d" (tmp)
+ : "a" (loops)
+ );
+ } else
+ __asm__ __volatile__ (
+ "LSETUP(1f, 1f) LC0 = %0;"
+ "1: NOP;"
+ :
+ : "a" (loops)
+ : "LT0", "LB0", "LC0"
+ );
}
#include <linux/param.h> /* needed for HZ */
@@ -41,4 +59,4 @@ static inline void udelay(unsigned long usecs)
__delay(usecs * loops_per_jiffy / (1000000 / HZ));
}
-#endif /* defined(_BLACKFIN_DELAY_H) */
+#endif