1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
|
/*
* linux/arch/arm/plat-omap/sram-fn.S
*
* Functions that need to be run in internal SRAM
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/linkage.h>
#include <asm/assembler.h>
#include <asm/arch/io.h>
#include <asm/hardware.h>
.text
/*
* Reprograms ULPD and CKCTL.
*/
ENTRY(sram_reprogram_clock)
stmfd sp!, {r0 - r12, lr} @ save registers on stack
mov r2, #IO_ADDRESS(DPLL_CTL) & 0xff000000
orr r2, r2, #IO_ADDRESS(DPLL_CTL) & 0x00ff0000
orr r2, r2, #IO_ADDRESS(DPLL_CTL) & 0x0000ff00
mov r3, #IO_ADDRESS(ARM_CKCTL) & 0xff000000
orr r3, r3, #IO_ADDRESS(ARM_CKCTL) & 0x00ff0000
orr r3, r3, #IO_ADDRESS(ARM_CKCTL) & 0x0000ff00
tst r0, #1 << 4 @ want lock mode?
beq newck @ nope
bic r0, r0, #1 << 4 @ else clear lock bit
strh r0, [r2] @ set dpll into bypass mode
orr r0, r0, #1 << 4 @ set lock bit again
newck:
strh r1, [r3] @ write new ckctl value
strh r0, [r2] @ write new dpll value
mov r4, #0x0700 @ let the clocks settle
orr r4, r4, #0x00ff
delay: sub r4, r4, #1
cmp r4, #0
bne delay
lock: ldrh r4, [r2], #0 @ read back dpll value
tst r0, #1 << 4 @ want lock mode?
beq out @ nope
tst r4, #1 << 0 @ dpll rate locked?
beq lock @ try again
out:
ldmfd sp!, {r0 - r12, pc} @ restore regs and return
ENTRY(sram_reprogram_clock_sz)
.word . - sram_reprogram_clock
|
