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authorRalf Baechle <ralf@linux-mips.org>2009-02-28 04:44:28 -0500
committerRalf Baechle <ralf@linux-mips.org>2009-06-08 11:57:51 -0400
commit5636919b5c909fee54a6ef5226475ecae012ad02 (patch)
treec77fa89c56ee2d493fb82117ab5dbc5b28a8deeb
parent3a553147eaad5d4de90ab1f695aa13ddbea684ec (diff)
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>
Diffstat
-rw-r--r--arch/mips/include/asm/cpu-info.h4
-rw-r--r--arch/mips/include/asm/delay.h92
-rw-r--r--arch/mips/kernel/proc.c2
-rw-r--r--arch/mips/lib/Makefile4
-rw-r--r--arch/mips/lib/delay.c56
5 files changed, 66 insertions, 92 deletions
diff --git a/arch/mips/include/asm/cpu-info.h b/arch/mips/include/asm/cpu-info.h
index 744cd8fb107f..126044308dec 100644
--- a/arch/mips/include/asm/cpu-info.h
+++ b/arch/mips/include/asm/cpu-info.h
@@ -39,8 +39,8 @@ struct cache_desc {
39#define MIPS_CACHE_PINDEX 0x00000020 /* Physically indexed cache */ 39#define MIPS_CACHE_PINDEX 0x00000020 /* Physically indexed cache */
40 40
41struct cpuinfo_mips { 41struct cpuinfo_mips {
42 unsigned long udelay_val; 42 unsigned int udelay_val;
43 unsigned long asid_cache; 43 unsigned int asid_cache;
44 44
45 /* 45 /*
46 * Capability and feature descriptor structure for MIPS CPU 46 * Capability and feature descriptor structure for MIPS CPU
diff --git a/arch/mips/include/asm/delay.h b/arch/mips/include/asm/delay.h
index b0bccd2c4ed5..a07e51b2be13 100644
--- a/arch/mips/include/asm/delay.h
+++ b/arch/mips/include/asm/delay.h
@@ -11,94 +11,12 @@
11#ifndef _ASM_DELAY_H 11#ifndef _ASM_DELAY_H
12#define _ASM_DELAY_H 12#define _ASM_DELAY_H
13 13
14#include <linux/param.h> 14extern void __delay(unsigned int loops);
15#include <linux/smp.h> 15extern void __ndelay(unsigned int ns);
16extern void __udelay(unsigned int us);
16 17
17#include <asm/compiler.h> 18#define ndelay(ns) __udelay(ns)
18#include <asm/war.h> 19#define udelay(us) __udelay(us)
19
20static inline void __delay(unsigned long loops)
21{
22 if (sizeof(long) == 4)
23 __asm__ __volatile__ (
24 " .set noreorder \n"
25 " .align 3 \n"
26 "1: bnez %0, 1b \n"
27 " subu %0, 1 \n"
28 " .set reorder \n"
29 : "=r" (loops)
30 : "0" (loops));
31 else if (sizeof(long) == 8 && !DADDI_WAR)
32 __asm__ __volatile__ (
33 " .set noreorder \n"
34 " .align 3 \n"
35 "1: bnez %0, 1b \n"
36 " dsubu %0, 1 \n"
37 " .set reorder \n"
38 : "=r" (loops)
39 : "0" (loops));
40 else if (sizeof(long) == 8 && DADDI_WAR)
41 __asm__ __volatile__ (
42 " .set noreorder \n"
43 " .align 3 \n"
44 "1: bnez %0, 1b \n"
45 " dsubu %0, %2 \n"
46 " .set reorder \n"
47 : "=r" (loops)
48 : "0" (loops), "r" (1));
49}
50
51
52/*
53 * Division by multiplication: you don't have to worry about
54 * loss of precision.
55 *
56 * Use only for very small delays ( < 1 msec). Should probably use a
57 * lookup table, really, as the multiplications take much too long with
58 * short delays. This is a "reasonable" implementation, though (and the
59 * first constant multiplications gets optimized away if the delay is
60 * a constant)
61 */
62
63static inline void __udelay(unsigned long usecs, unsigned long lpj)
64{
65 unsigned long hi, lo;
66
67 /*
68 * The rates of 128 is rounded wrongly by the catchall case
69 * for 64-bit. Excessive precission? Probably ...
70 */
71#if defined(CONFIG_64BIT) && (HZ == 128)
72 usecs *= 0x0008637bd05af6c7UL; /* 2**64 / (1000000 / HZ) */
73#elif defined(CONFIG_64BIT)
74 usecs *= (0x8000000000000000UL / (500000 / HZ));
75#else /* 32-bit junk follows here */
76 usecs *= (unsigned long) (((0x8000000000000000ULL / (500000 / HZ)) +
77 0x80000000ULL) >> 32);
78#endif
79
80 if (sizeof(long) == 4)
81 __asm__("multu\t%2, %3"
82 : "=h" (usecs), "=l" (lo)
83 : "r" (usecs), "r" (lpj)
84 : GCC_REG_ACCUM);
85 else if (sizeof(long) == 8 && !R4000_WAR)
86 __asm__("dmultu\t%2, %3"
87 : "=h" (usecs), "=l" (lo)
88 : "r" (usecs), "r" (lpj)
89 : GCC_REG_ACCUM);
90 else if (sizeof(long) == 8 && R4000_WAR)
91 __asm__("dmultu\t%3, %4\n\tmfhi\t%0"
92 : "=r" (usecs), "=h" (hi), "=l" (lo)
93 : "r" (usecs), "r" (lpj)
94 : GCC_REG_ACCUM);
95
96 __delay(usecs);
97}
98
99#define __udelay_val cpu_data[raw_smp_processor_id()].udelay_val
100
101#define udelay(usecs) __udelay((usecs), __udelay_val)
102 20
103/* make sure "usecs *= ..." in udelay do not overflow. */ 21/* make sure "usecs *= ..." in udelay do not overflow. */
104#if HZ >= 1000 22#if HZ >= 1000
diff --git a/arch/mips/kernel/proc.c b/arch/mips/kernel/proc.c
index 26760cad8b69..e0a4ac18fa07 100644
--- a/arch/mips/kernel/proc.c
+++ b/arch/mips/kernel/proc.c
@@ -42,7 +42,7 @@ static int show_cpuinfo(struct seq_file *m, void *v)
42 seq_printf(m, fmt, __cpu_name[n], 42 seq_printf(m, fmt, __cpu_name[n],
43 (version >> 4) & 0x0f, version & 0x0f, 43 (version >> 4) & 0x0f, version & 0x0f,
44 (fp_vers >> 4) & 0x0f, fp_vers & 0x0f); 44 (fp_vers >> 4) & 0x0f, fp_vers & 0x0f);
45 seq_printf(m, "BogoMIPS\t\t: %lu.%02lu\n", 45 seq_printf(m, "BogoMIPS\t\t: %u.%02u\n",
46 cpu_data[n].udelay_val / (500000/HZ), 46 cpu_data[n].udelay_val / (500000/HZ),
47 (cpu_data[n].udelay_val / (5000/HZ)) % 100); 47 (cpu_data[n].udelay_val / (5000/HZ)) % 100);
48 seq_printf(m, "wait instruction\t: %s\n", cpu_wait ? "yes" : "no"); 48 seq_printf(m, "wait instruction\t: %s\n", cpu_wait ? "yes" : "no");
diff --git a/arch/mips/lib/Makefile b/arch/mips/lib/Makefile
index c13c7ad2cdae..2adead5a8a37 100644
--- a/arch/mips/lib/Makefile
+++ b/arch/mips/lib/Makefile
@@ -2,8 +2,8 @@
2# Makefile for MIPS-specific library files.. 2# Makefile for MIPS-specific library files..
3# 3#
4 4
5lib-y += csum_partial.o memcpy.o memcpy-inatomic.o memset.o strlen_user.o \ 5lib-y += csum_partial.o delay.o memcpy.o memcpy-inatomic.o memset.o \
6 strncpy_user.o strnlen_user.o uncached.o 6 strlen_user.o strncpy_user.o strnlen_user.o uncached.o
7 7
8obj-y += iomap.o 8obj-y += iomap.o
9obj-$(CONFIG_PCI) += iomap-pci.o 9obj-$(CONFIG_PCI) += iomap-pci.o
diff --git a/arch/mips/lib/delay.c b/arch/mips/lib/delay.c
new file mode 100644
index 000000000000..f69c6b569eb3
--- /dev/null
+++ b/arch/mips/lib/delay.c
@@ -0,0 +1,56 @@
1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (C) 1994 by Waldorf Electronics
7 * Copyright (C) 1995 - 2000, 01, 03 by Ralf Baechle
8 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
9 * Copyright (C) 2007 Maciej W. Rozycki
10 */
11#include <linux/module.h>
12#include <linux/param.h>
13#include <linux/smp.h>
14
15#include <asm/compiler.h>
16#include <asm/war.h>
17
18inline void __delay(unsigned int loops)
19{
20 __asm__ __volatile__ (
21 " .set noreorder \n"
22 " .align 3 \n"
23 "1: bnez %0, 1b \n"
24 " subu %0, 1 \n"
25 " .set reorder \n"
26 : "=r" (loops)
27 : "0" (loops));
28}
29EXPORT_SYMBOL(__delay);
30
31/*
32 * Division by multiplication: you don't have to worry about
33 * loss of precision.
34 *
35 * Use only for very small delays ( < 1 msec). Should probably use a
36 * lookup table, really, as the multiplications take much too long with
37 * short delays. This is a "reasonable" implementation, though (and the
38 * first constant multiplications gets optimized away if the delay is
39 * a constant)
40 */
41
42void __udelay(unsigned long us)
43{
44 unsigned int lpj = current_cpu_data.udelay_val;
45
46 __delay((us * 0x000010c7 * HZ * lpj) >> 32);
47}
48EXPORT_SYMBOL(__udelay);
49
50void __ndelay(unsigned long ns)
51{
52 unsigned int lpj = current_cpu_data.udelay_val;
53
54 __delay((us * 0x00000005 * HZ * lpj) >> 32);
55}
56EXPORT_SYMBOL(__ndelay);
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-15 16:50:48 -0500