projects / mirror_ubuntu-kernels.git / blame
| Commit | Line | Data |
|---|---|---|
| 2874c5fd | 1 | /* SPDX-License-Identifier: GPL-2.0-or-later */ |
| 0c176fa8 MG |
2 | /* |
| 3 | * Copied from <file:arch/powerpc/kernel/misc_32.S> | |
| 4 | * | |
| 5 | * This file contains miscellaneous low-level functions. | |
| 6 | * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) | |
| 7 | * | |
| 8 | * Largely rewritten by Cort Dougan (cort@cs.nmt.edu) | |
| 9 | * and Paul Mackerras. | |
| 10 | * | |
| 11 | * kexec bits: | |
| 12 | * Copyright (C) 2002-2003 Eric Biederman <ebiederm@xmission.com> | |
| 13 | * GameCube/ppc32 port Copyright (C) 2004 Albert Herranz | |
| 0c176fa8 MG |
14 | */ |
| 15 | #include "ppc_asm.h" | |
| 16 | ||
| 17 | #define SPRN_PVR 0x11F /* Processor Version Register */ | |
| 18 | ||
| 19 | .text | |
| 20 | ||
| 21 | /* udelay (on non-601 processors) needs to know the period of the | |
| 22 | * timebase in nanoseconds. This used to be hardcoded to be 60ns | |
| 23 | * (period of 66MHz/4). Now a variable is used that is initialized to | |
| 24 | * 60 for backward compatibility, but it can be overridden as necessary | |
| 25 | * with code something like this: | |
| 26 | * extern unsigned long timebase_period_ns; | |
| 27 | * timebase_period_ns = 1000000000 / bd->bi_tbfreq; | |
| 28 | */ | |
| 29 | .data | |
| 30 | .globl timebase_period_ns | |
| 31 | timebase_period_ns: | |
| 32 | .long 60 | |
| 33 | ||
| 34 | .text | |
| 35 | /* | |
| 36 | * Delay for a number of microseconds | |
| 37 | */ | |
| 38 | .globl udelay | |
| 39 | udelay: | |
| 40 | mfspr r4,SPRN_PVR | |
| 41 | srwi r4,r4,16 | |
| 42 | cmpwi 0,r4,1 /* 601 ? */ | |
| b1576fec | 43 | bne .Ludelay_not_601 |
| 0c176fa8 MG |
44 | 00: li r0,86 /* Instructions / microsecond? */ |
| 45 | mtctr r0 | |
| 46 | 10: addi r0,r0,0 /* NOP */ | |
| 47 | bdnz 10b | |
| 48 | subic. r3,r3,1 | |
| 49 | bne 00b | |
| 50 | blr | |
| 51 | ||
| b1576fec | 52 | .Ludelay_not_601: |
| 0c176fa8 MG |
53 | mulli r4,r3,1000 /* nanoseconds */ |
| 54 | /* Change r4 to be the number of ticks using: | |
| 55 | * (nanoseconds + (timebase_period_ns - 1 )) / timebase_period_ns | |
| 56 | * timebase_period_ns defaults to 60 (16.6MHz) */ | |
| 57 | mflr r5 | |
| 58 | bl 0f | |
| 59 | 0: mflr r6 | |
| 60 | mtlr r5 | |
| 61 | lis r5,0b@ha | |
| 62 | addi r5,r5,0b@l | |
| 63 | subf r5,r5,r6 /* In case we're relocated */ | |
| 64 | addis r5,r5,timebase_period_ns@ha | |
| 65 | lwz r5,timebase_period_ns@l(r5) | |
| 66 | add r4,r4,r5 | |
| 67 | addi r4,r4,-1 | |
| 68 | divw r4,r4,r5 /* BUS ticks */ | |
| 72e4b2cd CL |
69 | 1: MFTBU(r5) |
| 70 | MFTBL(r6) | |
| 71 | MFTBU(r7) | |
| 0c176fa8 MG |
72 | cmpw 0,r5,r7 |
| 73 | bne 1b /* Get [synced] base time */ | |
| 74 | addc r9,r6,r4 /* Compute end time */ | |
| 75 | addze r8,r5 | |
| 72e4b2cd | 76 | 2: MFTBU(r5) |
| 0c176fa8 MG |
77 | cmpw 0,r5,r8 |
| 78 | blt 2b | |
| 79 | bgt 3f | |
| 72e4b2cd | 80 | MFTBL(r6) |
| 0c176fa8 MG |
81 | cmpw 0,r6,r9 |
| 82 | blt 2b | |
| 83 | 3: blr |