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1 | /* | |
2 | * linux/arch/arm/mach-omap1/timer32k.c | |
3 | * | |
4 | * OMAP 32K Timer | |
5 | * | |
6 | * Copyright (C) 2004 - 2005 Nokia Corporation | |
7 | * Partial timer rewrite and additional dynamic tick timer support by | |
8 | * Tony Lindgen <tony@atomide.com> and | |
9 | * Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com> | |
10 | * OMAP Dual-mode timer framework support by Timo Teras | |
11 | * | |
12 | * MPU timer code based on the older MPU timer code for OMAP | |
13 | * Copyright (C) 2000 RidgeRun, Inc. | |
14 | * Author: Greg Lonnon <glonnon@ridgerun.com> | |
15 | * | |
16 | * This program is free software; you can redistribute it and/or modify it | |
17 | * under the terms of the GNU General Public License as published by the | |
18 | * Free Software Foundation; either version 2 of the License, or (at your | |
19 | * option) any later version. | |
20 | * | |
21 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED | |
22 | * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF | |
23 | * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN | |
24 | * NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | |
25 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
26 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF | |
27 | * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON | |
28 | * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
29 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |
30 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
31 | * | |
32 | * You should have received a copy of the GNU General Public License along | |
33 | * with this program; if not, write to the Free Software Foundation, Inc., | |
34 | * 675 Mass Ave, Cambridge, MA 02139, USA. | |
35 | */ | |
36 | ||
37 | #include <linux/kernel.h> | |
38 | #include <linux/init.h> | |
39 | #include <linux/delay.h> | |
40 | #include <linux/interrupt.h> | |
41 | #include <linux/sched.h> | |
42 | #include <linux/spinlock.h> | |
43 | #include <linux/err.h> | |
44 | #include <linux/clk.h> | |
45 | #include <linux/clocksource.h> | |
46 | #include <linux/clockchips.h> | |
47 | #include <linux/io.h> | |
48 | ||
49 | #include <asm/irq.h> | |
50 | #include <asm/mach/irq.h> | |
51 | #include <asm/mach/time.h> | |
52 | ||
53 | #include <plat/counter-32k.h> | |
54 | ||
55 | #include <mach/hardware.h> | |
56 | ||
57 | #include "common.h" | |
58 | ||
59 | /* | |
60 | * --------------------------------------------------------------------------- | |
61 | * 32KHz OS timer | |
62 | * | |
63 | * This currently works only on 16xx, as 1510 does not have the continuous | |
64 | * 32KHz synchronous timer. The 32KHz synchronous timer is used to keep track | |
65 | * of time in addition to the 32KHz OS timer. Using only the 32KHz OS timer | |
66 | * on 1510 would be possible, but the timer would not be as accurate as | |
67 | * with the 32KHz synchronized timer. | |
68 | * --------------------------------------------------------------------------- | |
69 | */ | |
70 | ||
71 | /* 16xx specific defines */ | |
72 | #define OMAP1_32K_TIMER_BASE 0xfffb9000 | |
73 | #define OMAP1_32KSYNC_TIMER_BASE 0xfffbc400 | |
74 | #define OMAP1_32K_TIMER_CR 0x08 | |
75 | #define OMAP1_32K_TIMER_TVR 0x00 | |
76 | #define OMAP1_32K_TIMER_TCR 0x04 | |
77 | ||
78 | #define OMAP_32K_TICKS_PER_SEC (32768) | |
79 | ||
80 | /* | |
81 | * TRM says 1 / HZ = ( TVR + 1) / 32768, so TRV = (32768 / HZ) - 1 | |
82 | * so with HZ = 128, TVR = 255. | |
83 | */ | |
84 | #define OMAP_32K_TIMER_TICK_PERIOD ((OMAP_32K_TICKS_PER_SEC / HZ) - 1) | |
85 | ||
86 | #define JIFFIES_TO_HW_TICKS(nr_jiffies, clock_rate) \ | |
87 | (((nr_jiffies) * (clock_rate)) / HZ) | |
88 | ||
89 | static inline void omap_32k_timer_write(int val, int reg) | |
90 | { | |
91 | omap_writew(val, OMAP1_32K_TIMER_BASE + reg); | |
92 | } | |
93 | ||
94 | static inline void omap_32k_timer_start(unsigned long load_val) | |
95 | { | |
96 | if (!load_val) | |
97 | load_val = 1; | |
98 | omap_32k_timer_write(load_val, OMAP1_32K_TIMER_TVR); | |
99 | omap_32k_timer_write(0x0f, OMAP1_32K_TIMER_CR); | |
100 | } | |
101 | ||
102 | static inline void omap_32k_timer_stop(void) | |
103 | { | |
104 | omap_32k_timer_write(0x0, OMAP1_32K_TIMER_CR); | |
105 | } | |
106 | ||
107 | #define omap_32k_timer_ack_irq() | |
108 | ||
109 | static int omap_32k_timer_set_next_event(unsigned long delta, | |
110 | struct clock_event_device *dev) | |
111 | { | |
112 | omap_32k_timer_start(delta); | |
113 | ||
114 | return 0; | |
115 | } | |
116 | ||
117 | static int omap_32k_timer_shutdown(struct clock_event_device *evt) | |
118 | { | |
119 | omap_32k_timer_stop(); | |
120 | return 0; | |
121 | } | |
122 | ||
123 | static int omap_32k_timer_set_periodic(struct clock_event_device *evt) | |
124 | { | |
125 | omap_32k_timer_stop(); | |
126 | omap_32k_timer_start(OMAP_32K_TIMER_TICK_PERIOD); | |
127 | return 0; | |
128 | } | |
129 | ||
130 | static struct clock_event_device clockevent_32k_timer = { | |
131 | .name = "32k-timer", | |
132 | .features = CLOCK_EVT_FEAT_PERIODIC | | |
133 | CLOCK_EVT_FEAT_ONESHOT, | |
134 | .set_next_event = omap_32k_timer_set_next_event, | |
135 | .set_state_shutdown = omap_32k_timer_shutdown, | |
136 | .set_state_periodic = omap_32k_timer_set_periodic, | |
137 | .set_state_oneshot = omap_32k_timer_shutdown, | |
138 | .tick_resume = omap_32k_timer_shutdown, | |
139 | }; | |
140 | ||
141 | static irqreturn_t omap_32k_timer_interrupt(int irq, void *dev_id) | |
142 | { | |
143 | struct clock_event_device *evt = &clockevent_32k_timer; | |
144 | omap_32k_timer_ack_irq(); | |
145 | ||
146 | evt->event_handler(evt); | |
147 | ||
148 | return IRQ_HANDLED; | |
149 | } | |
150 | ||
151 | static struct irqaction omap_32k_timer_irq = { | |
152 | .name = "32KHz timer", | |
153 | .flags = IRQF_TIMER | IRQF_IRQPOLL, | |
154 | .handler = omap_32k_timer_interrupt, | |
155 | }; | |
156 | ||
157 | static __init void omap_init_32k_timer(void) | |
158 | { | |
159 | setup_irq(INT_OS_TIMER, &omap_32k_timer_irq); | |
160 | ||
161 | clockevent_32k_timer.cpumask = cpumask_of(0); | |
162 | clockevents_config_and_register(&clockevent_32k_timer, | |
163 | OMAP_32K_TICKS_PER_SEC, 1, 0xfffffffe); | |
164 | } | |
165 | ||
166 | /* | |
167 | * --------------------------------------------------------------------------- | |
168 | * Timer initialization | |
169 | * --------------------------------------------------------------------------- | |
170 | */ | |
171 | int __init omap_32k_timer_init(void) | |
172 | { | |
173 | int ret = -ENODEV; | |
174 | ||
175 | if (cpu_is_omap16xx()) { | |
176 | void __iomem *base; | |
177 | struct clk *sync32k_ick; | |
178 | ||
179 | base = ioremap(OMAP1_32KSYNC_TIMER_BASE, SZ_1K); | |
180 | if (!base) { | |
181 | pr_err("32k_counter: failed to map base addr\n"); | |
182 | return -ENODEV; | |
183 | } | |
184 | ||
185 | sync32k_ick = clk_get(NULL, "omap_32ksync_ick"); | |
186 | if (!IS_ERR(sync32k_ick)) | |
187 | clk_enable(sync32k_ick); | |
188 | ||
189 | ret = omap_init_clocksource_32k(base); | |
190 | } | |
191 | ||
192 | if (!ret) | |
193 | omap_init_32k_timer(); | |
194 | ||
195 | return ret; | |
196 | } |