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(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(sram_reprogram_clock_sz)
57	.word	. - sram_reprogram_clock
58