1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * linux/arch/arm/plat-omap/sram-fn.S
4 *
5 * Functions that need to be run in internal SRAM
6 */
7
8#include <linux/linkage.h>
9#include <linux/soc/ti/omap1-io.h>
10
11#include <asm/assembler.h>
12
13#include "hardware.h"
14#include "iomap.h"
15
16	.text
17
18/*
19 * Reprograms ULPD and CKCTL.
20 */
21	.align	3
22ENTRY(omap1_sram_reprogram_clock)
23	stmfd	sp!, {r0 - r12, lr}		@ save registers on stack
24
25	mov	r2, #OMAP1_IO_ADDRESS(DPLL_CTL) & 0xff000000
26	orr	r2, r2, #OMAP1_IO_ADDRESS(DPLL_CTL) & 0x00ff0000
27	orr	r2, r2, #OMAP1_IO_ADDRESS(DPLL_CTL) & 0x0000ff00
28
29	mov	r3, #OMAP1_IO_ADDRESS(ARM_CKCTL) & 0xff000000
30	orr	r3, r3, #OMAP1_IO_ADDRESS(ARM_CKCTL) & 0x00ff0000
31	orr	r3, r3, #OMAP1_IO_ADDRESS(ARM_CKCTL) & 0x0000ff00
32
33	tst	r0, #1 << 4			@ want lock mode?
34	beq	newck				@ nope
35	bic	r0, r0, #1 << 4			@ else clear lock bit
36	strh	r0, [r2]			@ set dpll into bypass mode
37	orr	r0, r0, #1 << 4			@ set lock bit again
38
39newck:
40	strh	r1, [r3]			@ write new ckctl value
41	strh	r0, [r2]			@ write new dpll value
42
43	mov	r4, #0x0700			@ let the clocks settle
44	orr	r4, r4, #0x00ff
45delay:	sub	r4, r4, #1
46	cmp	r4, #0
47	bne	delay
48
49lock:	ldrh	r4, [r2], #0			@ read back dpll value
50	tst	r0, #1 << 4			@ want lock mode?
51	beq	out				@ nope
52	tst	r4, #1 << 0			@ dpll rate locked?
53	beq	lock				@ try again
54
55out:
56	ldmfd	sp!, {r0 - r12, pc}		@ restore regs and return
57ENTRY(omap1_sram_reprogram_clock_sz)
58	.word	. - omap1_sram_reprogram_clock
59