1 /*
2 * (C) Copyright 2007
3 * Sascha Hauer, Pengutronix
4 *
5 * (C) Copyright 2008-2009 Freescale Semiconductor, Inc.
6 *
7 * SPDX-License-Identifier: GPL-2.0+
8 */
9
10 #include <common.h>
11 #include <asm/io.h>
12 #include <asm/arch/imx-regs.h>
13 #include <asm/arch/crm_regs.h>
14
15 DECLARE_GLOBAL_DATA_PTR;
16
17 /* General purpose timers bitfields */
18 #define GPTCR_SWR (1<<15) /* Software reset */
19 #define GPTCR_FRR (1<<9) /* Freerun / restart */
20 #define GPTCR_CLKSOURCE_32 (4<<6) /* Clock source */
21 #define GPTCR_TEN (1) /* Timer enable */
22
23 /*
24 * nothing really to do with interrupts, just starts up a counter.
25 * The 32KHz 32-bit timer overruns in 134217 seconds
26 */
timer_init(void)27 int timer_init(void)
28 {
29 int i;
30 struct gpt_regs *gpt = (struct gpt_regs *)GPT1_BASE_ADDR;
31 struct ccm_regs *ccm = (struct ccm_regs *)CCM_BASE_ADDR;
32
33 /* setup GP Timer 1 */
34 writel(GPTCR_SWR, &gpt->ctrl);
35
36 writel(readl(&ccm->cgr1) | 3 << MXC_CCM_CGR1_GPT_OFFSET, &ccm->cgr1);
37
38 for (i = 0; i < 100; i++)
39 writel(0, &gpt->ctrl); /* We have no udelay by now */
40 writel(0, &gpt->pre); /* prescaler = 1 */
41 /* Freerun Mode, 32KHz input */
42 writel(readl(&gpt->ctrl) | GPTCR_CLKSOURCE_32 | GPTCR_FRR,
43 &gpt->ctrl);
44 writel(readl(&gpt->ctrl) | GPTCR_TEN, &gpt->ctrl);
45
46 return 0;
47 }
48