3 * Sascha Hauer, Pengutronix
5 * (C) Copyright 2009 Freescale Semiconductor, Inc.
7 * See file CREDITS for list of people who contributed to this
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License as
12 * published by the Free Software Foundation; either version 2 of
13 * the License, or (at your option) any later version.
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
29 #include <asm/arch/imx-regs.h>
31 /* General purpose timers registers */
34 unsigned int prescaler;
36 unsigned int nouse[6];
40 static struct mxc_gpt *cur_gpt = (struct mxc_gpt *)GPT1_BASE_ADDR;
42 /* General purpose timers bitfields */
43 #define GPTCR_SWR (1 << 15) /* Software reset */
44 #define GPTCR_FRR (1 << 9) /* Freerun / restart */
45 #define GPTCR_CLKSOURCE_IPG (1 << 6) /* Clock source */
46 #define GPTCR_CLKSOURCE_CKIH (2 << 6)
47 #define GPTCR_CLKSOURCE_32kHz (4 << 6)
48 #define GPTCR_CLKSOURCE_OSC (5 << 6)
49 #define GPTCR_CLKSOURCE_MASK (7 << 6)
50 #define GPTCR_TEN 1 /* Timer enable */
52 #define GPT_CLKSOURCE GPTCR_CLKSOURCE_32kHz
53 #define GPT_REFCLK 32768
54 #define GPT_PRESCALER 1
55 #define GPT_CLK (GPT_REFCLK / GPT_PRESCALER)
57 #ifdef DEBUG_TIMER_WRAP
59 * Let the timer wrap 30 seconds after start to catch misbehaving
60 * timer related code early
62 #define TIMER_START (-time_to_tick(30 * CONFIG_SYS_HZ))
64 #define TIMER_START 0UL
67 DECLARE_GLOBAL_DATA_PTR;
69 static inline unsigned long tick_to_time(unsigned long tick)
71 unsigned long long t = (unsigned long long)tick * CONFIG_SYS_HZ;
76 static inline unsigned long time_to_tick(unsigned long time)
78 unsigned long long ticks = (unsigned long long)time;
81 do_div(ticks, CONFIG_SYS_HZ);
85 static inline unsigned long us_to_tick(unsigned long usec)
87 unsigned long long ticks = (unsigned long long)usec;
90 do_div(ticks, 1000 * CONFIG_SYS_HZ);
99 /* setup GP Timer 1 */
100 __raw_writel(GPTCR_SWR, &cur_gpt->control);
102 /* We have no udelay by now */
103 for (i = 0; i < 100; i++)
104 __raw_writel(0, &cur_gpt->control);
106 __raw_writel(0, &cur_gpt->prescaler);
108 /* Freerun Mode, PERCLK1 input */
109 i = __raw_readl(&cur_gpt->control);
110 i &= ~GPTCR_CLKSOURCE_MASK;
111 __raw_writel(i | GPT_CLKSOURCE | GPTCR_TEN, &cur_gpt->control);
113 val = __raw_readl(&cur_gpt->counter);
116 gd->tbl = TIMER_START;
117 gd->timer_rate_hz = GPT_CLK;
122 unsigned long long get_ticks(void)
124 ulong now = __raw_readl(&cur_gpt->counter); /* current tick value */
125 ulong inc = now - gd->lastinc;
132 ulong get_timer_masked(void)
135 * get_ticks() returns a long long (64 bit), it wraps in
136 * 2^64 / CONFIG_MX25_CLK32 = 2^64 / 2^15 = 2^49 ~ 5 * 10^14 (s) ~
137 * 5 * 10^9 days... and get_ticks() * CONFIG_SYS_HZ wraps in
138 * 5 * 10^6 days - long enough.
141 * LW: get_ticks() returns a long long with the top 32 bits always ZERO!
142 * Thus the calculation above is not true.
143 * A 64bit timer value would only make sense if it was
144 * consistently used throughout the code. Thus also the parameter
145 * to get_timer() and its return value would need to be 64bit wide!
147 return tick_to_time(get_ticks());
150 ulong get_timer(ulong base)
152 return tick_to_time(get_ticks() - time_to_tick(base));
155 /* delay x useconds AND preserve advance timstamp value */
156 void __udelay(unsigned long usec)
158 unsigned long start = __raw_readl(&cur_gpt->counter);
164 ticks = us_to_tick(usec);
168 while (__raw_readl(&cur_gpt->counter) - start < ticks)
169 /* loop till event */;
173 * This function is derived from PowerPC code (timebase clock frequency).
174 * On ARM it returns the number of timer ticks per second.
176 ulong get_tbclk(void)
178 return gd->timer_rate_hz;