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git.ipfire.org Git - people/ms/u-boot.git/blob - cpu/arm_cortexa8/omap3/timer.c
5 * Richard Woodruff <r-woodruff2@ti.com>
6 * Syed Moahmmed Khasim <khasim@ti.com>
9 * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
10 * Marius Groeger <mgroeger@sysgo.de>
11 * Alex Zuepke <azu@sysgo.de>
14 * Gary Jennejohn, DENX Software Engineering, <garyj@denx.de>
16 * See file CREDITS for list of people who contributed to this
19 * This program is free software; you can redistribute it and/or
20 * modify it under the terms of the GNU General Public License as
21 * published by the Free Software Foundation; either version 2 of
22 * the License, or (at your option) any later version.
24 * This program is distributed in the hope that it will be useful,
25 * but WITHOUT ANY WARRANTY; without even the implied warranty of
26 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
27 * GNU General Public License for more details.
29 * You should have received a copy of the GNU General Public License
30 * along with this program; if not, write to the Free Software
31 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
38 static ulong timestamp
;
40 static gptimer_t
*timer_base
= (gptimer_t
*)CONFIG_SYS_TIMERBASE
;
43 * Nothing really to do with interrupts, just starts up a counter.
44 * We run the counter with 13MHz, divided by 8, resulting in timer
45 * frequency of 1.625MHz. With 32bit counter register, counter
49 /* 13MHz / 8 = 1.625MHz */
50 #define TIMER_CLOCK (V_SCLK / (2 << CONFIG_SYS_PTV))
51 #define TIMER_LOAD_VAL 0xffffffff
55 /* start the counter ticking up, reload value on overflow */
56 writel(TIMER_LOAD_VAL
, &timer_base
->tldr
);
58 writel((CONFIG_SYS_PTV
<< 2) | TCLR_PRE
| TCLR_AR
| TCLR_ST
,
61 reset_timer_masked(); /* init the timestamp and lastinc value */
67 * timer without interrupts
69 void reset_timer(void)
74 ulong
get_timer(ulong base
)
76 return get_timer_masked() - base
;
79 void set_timer(ulong t
)
84 /* delay x useconds */
85 void udelay(unsigned long usec
)
87 long tmo
= usec
* (TIMER_CLOCK
/ 1000) / 1000;
88 unsigned long now
, last
= readl(&timer_base
->tcrr
);
91 now
= readl(&timer_base
->tcrr
);
92 if (last
> now
) /* count up timer overflow */
93 tmo
-= TIMER_LOAD_VAL
- last
+ now
;
100 void reset_timer_masked(void)
102 /* reset time, capture current incrementer value time */
103 lastinc
= readl(&timer_base
->tcrr
) / (TIMER_CLOCK
/ CONFIG_SYS_HZ
);
104 timestamp
= 0; /* start "advancing" time stamp from 0 */
107 ulong
get_timer_masked(void)
109 /* current tick value */
110 ulong now
= readl(&timer_base
->tcrr
) / (TIMER_CLOCK
/ CONFIG_SYS_HZ
);
112 if (now
>= lastinc
) /* normal mode (non roll) */
113 /* move stamp fordward with absoulte diff ticks */
114 timestamp
+= (now
- lastinc
);
115 else /* we have rollover of incrementer */
116 timestamp
+= ((TIMER_LOAD_VAL
/ (TIMER_CLOCK
/ CONFIG_SYS_HZ
))
123 * This function is derived from PowerPC code (read timebase as long long).
124 * On ARM it just returns the timer value.
126 unsigned long long get_ticks(void)
132 * This function is derived from PowerPC code (timebase clock frequency).
133 * On ARM it returns the number of timer ticks per second.
135 ulong
get_tbclk(void)
137 return CONFIG_SYS_HZ
;