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Marek Vasutc140e982011-11-08 23:18:08 +00001/*
2 * Freescale i.MX28 timer driver
3 *
4 * Copyright (C) 2011 Marek Vasut <marek.vasut@gmail.com>
5 * on behalf of DENX Software Engineering GmbH
6 *
7 * Based on code from LTIB:
8 * (C) Copyright 2009-2010 Freescale Semiconductor, Inc.
9 *
10 * See file CREDITS for list of people who contributed to this
11 * project.
12 *
13 * This program is free software; you can redistribute it and/or
14 * modify it under the terms of the GNU General Public License as
15 * published by the Free Software Foundation; either version 2 of
16 * the License, or (at your option) any later version.
17 *
18 * This program is distributed in the hope that it will be useful,
19 * but WITHOUT ANY WARRANTY; without even the implied warranty of
20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 * GNU General Public License for more details.
22 *
23 * You should have received a copy of the GNU General Public License
24 * along with this program; if not, write to the Free Software
25 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
26 * MA 02111-1307 USA
27 */
28
29#include <common.h>
30#include <asm/io.h>
31#include <asm/arch/imx-regs.h>
32#include <asm/arch/sys_proto.h>
33
34/* Maximum fixed count */
35#define TIMER_LOAD_VAL 0xffffffff
36
37DECLARE_GLOBAL_DATA_PTR;
38
39#define timestamp (gd->tbl)
40#define lastdec (gd->lastinc)
41
42/*
43 * This driver uses 1kHz clock source.
44 */
45#define MX28_INCREMENTER_HZ 1000
46
47static inline unsigned long tick_to_time(unsigned long tick)
48{
49 return tick / (MX28_INCREMENTER_HZ / CONFIG_SYS_HZ);
50}
51
52static inline unsigned long time_to_tick(unsigned long time)
53{
54 return time * (MX28_INCREMENTER_HZ / CONFIG_SYS_HZ);
55}
56
57/* Calculate how many ticks happen in "us" microseconds */
58static inline unsigned long us_to_tick(unsigned long us)
59{
60 return (us * MX28_INCREMENTER_HZ) / 1000000;
61}
62
63int timer_init(void)
64{
65 struct mx28_timrot_regs *timrot_regs =
66 (struct mx28_timrot_regs *)MXS_TIMROT_BASE;
67
68 /* Reset Timers and Rotary Encoder module */
69 mx28_reset_block(&timrot_regs->hw_timrot_rotctrl_reg);
70
71 /* Set fixed_count to 0 */
72 writel(0, &timrot_regs->hw_timrot_fixed_count0);
73
74 /* Set UPDATE bit and 1Khz frequency */
75 writel(TIMROT_TIMCTRLn_UPDATE | TIMROT_TIMCTRLn_RELOAD |
76 TIMROT_TIMCTRLn_SELECT_1KHZ_XTAL,
77 &timrot_regs->hw_timrot_timctrl0);
78
79 /* Set fixed_count to maximal value */
80 writel(TIMER_LOAD_VAL, &timrot_regs->hw_timrot_fixed_count0);
81
82 return 0;
83}
84
Marek Vasutc142b672012-02-07 06:47:31 +000085unsigned long long get_ticks(void)
Marek Vasutc140e982011-11-08 23:18:08 +000086{
87 struct mx28_timrot_regs *timrot_regs =
88 (struct mx28_timrot_regs *)MXS_TIMROT_BASE;
89
90 /* Current tick value */
91 uint32_t now = readl(&timrot_regs->hw_timrot_running_count0);
92
93 if (lastdec >= now) {
94 /*
95 * normal mode (non roll)
96 * move stamp forward with absolut diff ticks
97 */
98 timestamp += (lastdec - now);
99 } else {
100 /* we have rollover of decrementer */
101 timestamp += (TIMER_LOAD_VAL - now) + lastdec;
102
103 }
104 lastdec = now;
105
Marek Vasutc142b672012-02-07 06:47:31 +0000106 return timestamp;
107}
108
109ulong get_timer_masked(void)
110{
111 return tick_to_time(get_ticks());
Marek Vasutc140e982011-11-08 23:18:08 +0000112}
113
Marek Vasutc142b672012-02-07 06:47:31 +0000114ulong get_timer(ulong base)
115{
116 return get_timer_masked() - base;
117}
118
Marek Vasutc140e982011-11-08 23:18:08 +0000119/* We use the HW_DIGCTL_MICROSECONDS register for sub-millisecond timer. */
120#define MX28_HW_DIGCTL_MICROSECONDS 0x8001c0c0
121
122void __udelay(unsigned long usec)
123{
124 uint32_t old, new, incr;
125 uint32_t counter = 0;
126
127 old = readl(MX28_HW_DIGCTL_MICROSECONDS);
128
129 while (counter < usec) {
130 new = readl(MX28_HW_DIGCTL_MICROSECONDS);
131
132 /* Check if the timer wrapped. */
133 if (new < old) {
134 incr = 0xffffffff - old;
135 incr += new;
136 } else {
137 incr = new - old;
138 }
139
140 /*
141 * Check if we are close to the maximum time and the counter
142 * would wrap if incremented. If that's the case, break out
143 * from the loop as the requested delay time passed.
144 */
145 if (counter + incr < counter)
146 break;
147
148 counter += incr;
149 old = new;
150 }
151}
Marek Vasutc142b672012-02-07 06:47:31 +0000152
153ulong get_tbclk(void)
154{
155 return MX28_INCREMENTER_HZ;
156}