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linux/arch/mips/include/asm/delay.h

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Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 00:20:36 +02:00
/*
* 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) 1994 by Waldorf Electronics
* Copyright (C) 1995 - 2000, 01, 03 by Ralf Baechle
* Copyright (C) 1999, 2000 Silicon Graphics, Inc.
[MIPS] R4000/R4400 errata workarounds This is the gereric part of R4000/R4400 errata workarounds. They include compiler and assembler support as well as some source code modifications to address the problems with some combinations of multiply/divide+shift instructions as well as the daddi and daddiu instructions. Changes included are as follows: 1. New Kconfig options to select workarounds by platforms as necessary. 2. Arch top-level Makefile to pass necessary options to the compiler; also incompatible configurations are detected (-mno-sym32 unsupported as horribly intrusive for little gain). 3. Bug detection updated and shuffled -- the multiply/divide+shift problem is lethal enough that if not worked around it makes the kernel crash in time_init() because of a division by zero; the daddiu erratum might also trigger early potentially, though I have not observed it. On the other hand the daddi detection code requires the exception subsystem to have been initialised (and is there mainly for information). 4. r4k_daddiu_bug() added so that the existence of the erratum can be queried by code at the run time as necessary; useful for generated code like TLB fault and copy/clear page handlers. 5. __udelay() updated as it uses multiplication in inline assembly. Note that -mdaddi requires modified toolchain (which has been maintained by myself and available from my site for ~4years now -- versions covered are GCC 2.95.4 - 4.1.2 and binutils from 2.13 onwards). The -mfix-r4000 and -mfix-r4400 have been standard for a while though. Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-23 13:43:11 +02:00
* Copyright (C) 2007 Maciej W. Rozycki
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 00:20:36 +02:00
*/
#ifndef _ASM_DELAY_H
#define _ASM_DELAY_H
MIPS: Outline udelay and fix a few issues. Outlining fixes the issue were on certain CPUs such as the R10000 family the delay loop would need an extra cycle if it overlaps a cacheline boundary. The rewrite also fixes build errors with GCC 4.4 which was changed in way incompatible with the kernel's inline assembly. Relying on pure C for computation of the delay value removes the need for explicit. The price we pay is a slight slowdown of the computation - to be fixed on another day. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2009-02-28 10:44:28 +01:00
extern void __delay(unsigned int loops);
extern void __ndelay(unsigned int ns);
extern void __udelay(unsigned int us);
[MIPS] R4000/R4400 errata workarounds This is the gereric part of R4000/R4400 errata workarounds. They include compiler and assembler support as well as some source code modifications to address the problems with some combinations of multiply/divide+shift instructions as well as the daddi and daddiu instructions. Changes included are as follows: 1. New Kconfig options to select workarounds by platforms as necessary. 2. Arch top-level Makefile to pass necessary options to the compiler; also incompatible configurations are detected (-mno-sym32 unsupported as horribly intrusive for little gain). 3. Bug detection updated and shuffled -- the multiply/divide+shift problem is lethal enough that if not worked around it makes the kernel crash in time_init() because of a division by zero; the daddiu erratum might also trigger early potentially, though I have not observed it. On the other hand the daddi detection code requires the exception subsystem to have been initialised (and is there mainly for information). 4. r4k_daddiu_bug() added so that the existence of the erratum can be queried by code at the run time as necessary; useful for generated code like TLB fault and copy/clear page handlers. 5. __udelay() updated as it uses multiplication in inline assembly. Note that -mdaddi requires modified toolchain (which has been maintained by myself and available from my site for ~4years now -- versions covered are GCC 2.95.4 - 4.1.2 and binutils from 2.13 onwards). The -mfix-r4000 and -mfix-r4400 have been standard for a while though. Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-23 13:43:11 +02:00
MIPS: Fix typo resulting in far too long ndelay times. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2009-06-12 18:28:00 +02:00
#define ndelay(ns) __ndelay(ns)
MIPS: Outline udelay and fix a few issues. Outlining fixes the issue were on certain CPUs such as the R10000 family the delay loop would need an extra cycle if it overlaps a cacheline boundary. The rewrite also fixes build errors with GCC 4.4 which was changed in way incompatible with the kernel's inline assembly. Relying on pure C for computation of the delay value removes the need for explicit. The price we pay is a slight slowdown of the computation - to be fixed on another day. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2009-02-28 10:44:28 +01:00
#define udelay(us) __udelay(us)
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 00:20:36 +02:00
Define MAX_UDELAY_MS If HZ was 1000, mdelay(2) cause overflow on multiplication in __udelay. We should define MAX_UDELAY_MS properly to prevent this. Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2005-11-04 18:02:54 +01:00
/* make sure "usecs *= ..." in udelay do not overflow. */
#if HZ >= 1000
#define MAX_UDELAY_MS 1
#elif HZ <= 200
#define MAX_UDELAY_MS 5
#else
#define MAX_UDELAY_MS (1000 / HZ)
#endif
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 00:20:36 +02:00
#endif /* _ASM_DELAY_H */
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