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-rw-r--r--arch/arm/mach-omap1/sram.S57
1 files changed, 57 insertions, 0 deletions
diff --git a/arch/arm/mach-omap1/sram.S b/arch/arm/mach-omap1/sram.S
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1/*
2 * linux/arch/arm/plat-omap/sram-fn.S
3 *
4 * Functions that need to be run in internal SRAM
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10
11#include <linux/linkage.h>
12#include <asm/assembler.h>
13#include <asm/arch/io.h>
14#include <asm/hardware.h>
15
16 .text
17
18/*
19 * Reprograms ULPD and CKCTL.
20 */
21ENTRY(omap1_sram_reprogram_clock)
22 stmfd sp!, {r0 - r12, lr} @ save registers on stack
23
24 mov r2, #IO_ADDRESS(DPLL_CTL) & 0xff000000
25 orr r2, r2, #IO_ADDRESS(DPLL_CTL) & 0x00ff0000
26 orr r2, r2, #IO_ADDRESS(DPLL_CTL) & 0x0000ff00
27
28 mov r3, #IO_ADDRESS(ARM_CKCTL) & 0xff000000
29 orr r3, r3, #IO_ADDRESS(ARM_CKCTL) & 0x00ff0000
30 orr r3, r3, #IO_ADDRESS(ARM_CKCTL) & 0x0000ff00
31
32 tst r0, #1 << 4 @ want lock mode?
33 beq newck @ nope
34 bic r0, r0, #1 << 4 @ else clear lock bit
35 strh r0, [r2] @ set dpll into bypass mode
36 orr r0, r0, #1 << 4 @ set lock bit again
37
38newck:
39 strh r1, [r3] @ write new ckctl value
40 strh r0, [r2] @ write new dpll value
41
42 mov r4, #0x0700 @ let the clocks settle
43 orr r4, r4, #0x00ff
44delay: sub r4, r4, #1
45 cmp r4, #0
46 bne delay
47
48lock: ldrh r4, [r2], #0 @ read back dpll value
49 tst r0, #1 << 4 @ want lock mode?
50 beq out @ nope
51 tst r4, #1 << 0 @ dpll rate locked?
52 beq lock @ try again
53
54out:
55 ldmfd sp!, {r0 - r12, pc} @ restore regs and return
56ENTRY(omap1_sram_reprogram_clock_sz)
57 .word . - omap1_sram_reprogram_clock