Gitiles
Code Review Sign In
gerrit-public.fairphone.software / kernel / msm-4.9 / b1576fec7f4dd4657694fefc97fda4cf28ec68e9 / . / arch / powerpc / boot / util.S
blob: 243b8497d58b847a2877523c45df04f2f1326b32 [file] [log] [blame]
Mark A. Greer0c176fa2006-10-16 13:52:09 -0700[diff] [blame]1/*
2 * Copied from <file:arch/powerpc/kernel/misc_32.S>
3 *
4 * This file contains miscellaneous low-level functions.
5 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
6 *
7 * Largely rewritten by Cort Dougan (cort@cs.nmt.edu)
8 * and Paul Mackerras.
9 *
10 * kexec bits:
11 * Copyright (C) 2002-2003 Eric Biederman <ebiederm@xmission.com>
12 * GameCube/ppc32 port Copyright (C) 2004 Albert Herranz
13 *
14 * This program is free software; you can redistribute it and/or
15 * modify it under the terms of the GNU General Public License
16 * as published by the Free Software Foundation; either version
17 * 2 of the License, or (at your option) any later version.
18 *
19 */
20#include "ppc_asm.h"
21
22#define SPRN_PVR 0x11F /* Processor Version Register */
23
24 .text
25
26/* udelay (on non-601 processors) needs to know the period of the
27 * timebase in nanoseconds. This used to be hardcoded to be 60ns
28 * (period of 66MHz/4). Now a variable is used that is initialized to
29 * 60 for backward compatibility, but it can be overridden as necessary
30 * with code something like this:
31 * extern unsigned long timebase_period_ns;
32 * timebase_period_ns = 1000000000 / bd->bi_tbfreq;
33 */
34 .data
35 .globl timebase_period_ns
36timebase_period_ns:
37 .long 60
38
39 .text
40/*
41 * Delay for a number of microseconds
42 */
43 .globl udelay
44udelay:
45 mfspr r4,SPRN_PVR
46 srwi r4,r4,16
47 cmpwi 0,r4,1 /* 601 ? */
Anton Blanchardb1576fe2014-02-04 16:04:35 +1100[diff] [blame^]48 bne .Ludelay_not_601
Mark A. Greer0c176fa2006-10-16 13:52:09 -0700[diff] [blame]4900: li r0,86 /* Instructions / microsecond? */
50 mtctr r0
5110: addi r0,r0,0 /* NOP */
52 bdnz 10b
53 subic. r3,r3,1
54 bne 00b
55 blr
56
Anton Blanchardb1576fe2014-02-04 16:04:35 +1100[diff] [blame^]57.Ludelay_not_601:
Mark A. Greer0c176fa2006-10-16 13:52:09 -0700[diff] [blame]58 mulli r4,r3,1000 /* nanoseconds */
59 /* Change r4 to be the number of ticks using:
60 * (nanoseconds + (timebase_period_ns - 1 )) / timebase_period_ns
61 * timebase_period_ns defaults to 60 (16.6MHz) */
62 mflr r5
63 bl 0f
640: mflr r6
65 mtlr r5
66 lis r5,0b@ha
67 addi r5,r5,0b@l
68 subf r5,r5,r6 /* In case we're relocated */
69 addis r5,r5,timebase_period_ns@ha
70 lwz r5,timebase_period_ns@l(r5)
71 add r4,r4,r5
72 addi r4,r4,-1
73 divw r4,r4,r5 /* BUS ticks */
LEROY Christopheae2163b2013-11-22 17:57:31 +0100[diff] [blame]74#ifdef CONFIG_8xx
751: mftbu r5
76 mftb r6
77 mftbu r7
78#else
Scott Woodbeb2dc02013-08-20 19:33:12 -0500[diff] [blame]791: mfspr r5, SPRN_TBRU
80 mfspr r6, SPRN_TBRL
81 mfspr r7, SPRN_TBRU
LEROY Christopheae2163b2013-11-22 17:57:31 +0100[diff] [blame]82#endif
Mark A. Greer0c176fa2006-10-16 13:52:09 -0700[diff] [blame]83 cmpw 0,r5,r7
84 bne 1b /* Get [synced] base time */
85 addc r9,r6,r4 /* Compute end time */
86 addze r8,r5
LEROY Christopheae2163b2013-11-22 17:57:31 +0100[diff] [blame]87#ifdef CONFIG_8xx
882: mftbu r5
89#else
Scott Woodbeb2dc02013-08-20 19:33:12 -0500[diff] [blame]902: mfspr r5, SPRN_TBRU
LEROY Christopheae2163b2013-11-22 17:57:31 +0100[diff] [blame]91#endif
Mark A. Greer0c176fa2006-10-16 13:52:09 -0700[diff] [blame]92 cmpw 0,r5,r8
93 blt 2b
94 bgt 3f
LEROY Christopheae2163b2013-11-22 17:57:31 +0100[diff] [blame]95#ifdef CONFIG_8xx
96 mftb r6
97#else
Scott Woodbeb2dc02013-08-20 19:33:12 -0500[diff] [blame]98 mfspr r6, SPRN_TBRL
LEROY Christopheae2163b2013-11-22 17:57:31 +0100[diff] [blame]99#endif
Mark A. Greer0c176fa2006-10-16 13:52:09 -0700[diff] [blame]100 cmpw 0,r6,r9
101 blt 2b
1023: blr