2 * linux/arch/arm/plat-mxc/time.c
4 * Copyright (C) 2000-2001 Deep Blue Solutions
5 * Copyright (C) 2002 Shane Nay (shane@minirl.com)
6 * Copyright (C) 2006-2007 Pavel Pisa (ppisa@pikron.com)
7 * Copyright (C) 2008 Juergen Beisert (kernel@pengutronix.de)
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License
11 * as published by the Free Software Foundation; either version 2
12 * of the License, or (at your option) any later version.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
24 #include <linux/interrupt.h>
25 #include <linux/irq.h>
26 #include <linux/clockchips.h>
27 #include <linux/clk.h>
28 #include <linux/err.h>
30 #include <mach/hardware.h>
31 #include <asm/sched_clock.h>
32 #include <asm/mach/time.h>
33 #include <mach/common.h>
36 * There are 2 versions of the timer hardware on Freescale MXC hardware.
37 * Version 1: MX1/MXL, MX21, MX27.
38 * Version 2: MX25, MX31, MX35, MX37, MX51
41 /* defines common for all i.MX */
43 #define MXC_TCTL_TEN (1 << 0) /* Enable module */
44 #define MXC_TPRER 0x04
47 #define MX1_2_TCTL_CLK_PCLK1 (1 << 1)
48 #define MX1_2_TCTL_IRQEN (1 << 4)
49 #define MX1_2_TCTL_FRR (1 << 8)
50 #define MX1_2_TCMP 0x08
51 #define MX1_2_TCN 0x10
52 #define MX1_2_TSTAT 0x14
55 #define MX2_TSTAT_CAPT (1 << 1)
56 #define MX2_TSTAT_COMP (1 << 0)
58 /* MX31, MX35, MX25, MX5 */
59 #define V2_TCTL_WAITEN (1 << 3) /* Wait enable mode */
60 #define V2_TCTL_CLK_IPG (1 << 6)
61 #define V2_TCTL_FRR (1 << 9)
64 #define V2_TSTAT_OF1 (1 << 0)
68 #define timer_is_v1() (cpu_is_mx1() || cpu_is_mx21() || cpu_is_mx27())
69 #define timer_is_v2() (!timer_is_v1())
71 static struct clock_event_device clockevent_mxc;
72 static enum clock_event_mode clockevent_mode = CLOCK_EVT_MODE_UNUSED;
74 static void __iomem *timer_base;
76 static inline void gpt_irq_disable(void)
81 __raw_writel(0, timer_base + V2_IR);
83 tmp = __raw_readl(timer_base + MXC_TCTL);
84 __raw_writel(tmp & ~MX1_2_TCTL_IRQEN, timer_base + MXC_TCTL);
88 static inline void gpt_irq_enable(void)
91 __raw_writel(1<<0, timer_base + V2_IR);
93 __raw_writel(__raw_readl(timer_base + MXC_TCTL) | MX1_2_TCTL_IRQEN,
94 timer_base + MXC_TCTL);
98 static void gpt_irq_acknowledge(void)
102 __raw_writel(0, timer_base + MX1_2_TSTAT);
104 __raw_writel(MX2_TSTAT_CAPT | MX2_TSTAT_COMP,
105 timer_base + MX1_2_TSTAT);
106 } else if (timer_is_v2())
107 __raw_writel(V2_TSTAT_OF1, timer_base + V2_TSTAT);
110 static void __iomem *sched_clock_reg;
112 static u32 notrace mxc_read_sched_clock(void)
114 return sched_clock_reg ? __raw_readl(sched_clock_reg) : 0;
117 static int __init mxc_clocksource_init(struct clk *timer_clk)
119 unsigned int c = clk_get_rate(timer_clk);
120 void __iomem *reg = timer_base + (timer_is_v2() ? V2_TCN : MX1_2_TCN);
122 sched_clock_reg = reg;
124 setup_sched_clock(mxc_read_sched_clock, 32, c);
125 return clocksource_mmio_init(reg, "mxc_timer1", c, 200, 32,
126 clocksource_mmio_readl_up);
131 static int mx1_2_set_next_event(unsigned long evt,
132 struct clock_event_device *unused)
136 tcmp = __raw_readl(timer_base + MX1_2_TCN) + evt;
138 __raw_writel(tcmp, timer_base + MX1_2_TCMP);
140 return (int)(tcmp - __raw_readl(timer_base + MX1_2_TCN)) < 0 ?
144 static int v2_set_next_event(unsigned long evt,
145 struct clock_event_device *unused)
149 tcmp = __raw_readl(timer_base + V2_TCN) + evt;
151 __raw_writel(tcmp, timer_base + V2_TCMP);
153 return (int)(tcmp - __raw_readl(timer_base + V2_TCN)) < 0 ?
158 static const char *clock_event_mode_label[] = {
159 [CLOCK_EVT_MODE_PERIODIC] = "CLOCK_EVT_MODE_PERIODIC",
160 [CLOCK_EVT_MODE_ONESHOT] = "CLOCK_EVT_MODE_ONESHOT",
161 [CLOCK_EVT_MODE_SHUTDOWN] = "CLOCK_EVT_MODE_SHUTDOWN",
162 [CLOCK_EVT_MODE_UNUSED] = "CLOCK_EVT_MODE_UNUSED"
166 static void mxc_set_mode(enum clock_event_mode mode,
167 struct clock_event_device *evt)
172 * The timer interrupt generation is disabled at least
173 * for enough time to call mxc_set_next_event()
175 local_irq_save(flags);
177 /* Disable interrupt in GPT module */
180 if (mode != clockevent_mode) {
181 /* Set event time into far-far future */
183 __raw_writel(__raw_readl(timer_base + V2_TCN) - 3,
184 timer_base + V2_TCMP);
186 __raw_writel(__raw_readl(timer_base + MX1_2_TCN) - 3,
187 timer_base + MX1_2_TCMP);
189 /* Clear pending interrupt */
190 gpt_irq_acknowledge();
194 printk(KERN_INFO "mxc_set_mode: changing mode from %s to %s\n",
195 clock_event_mode_label[clockevent_mode],
196 clock_event_mode_label[mode]);
199 /* Remember timer mode */
200 clockevent_mode = mode;
201 local_irq_restore(flags);
204 case CLOCK_EVT_MODE_PERIODIC:
205 printk(KERN_ERR"mxc_set_mode: Periodic mode is not "
206 "supported for i.MX\n");
208 case CLOCK_EVT_MODE_ONESHOT:
210 * Do not put overhead of interrupt enable/disable into
211 * mxc_set_next_event(), the core has about 4 minutes
212 * to call mxc_set_next_event() or shutdown clock after
215 local_irq_save(flags);
217 local_irq_restore(flags);
219 case CLOCK_EVT_MODE_SHUTDOWN:
220 case CLOCK_EVT_MODE_UNUSED:
221 case CLOCK_EVT_MODE_RESUME:
222 /* Left event sources disabled, no more interrupts appear */
228 * IRQ handler for the timer
230 static irqreturn_t mxc_timer_interrupt(int irq, void *dev_id)
232 struct clock_event_device *evt = &clockevent_mxc;
236 tstat = __raw_readl(timer_base + V2_TSTAT);
238 tstat = __raw_readl(timer_base + MX1_2_TSTAT);
240 gpt_irq_acknowledge();
242 evt->event_handler(evt);
247 static struct irqaction mxc_timer_irq = {
248 .name = "i.MX Timer Tick",
249 .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
250 .handler = mxc_timer_interrupt,
253 static struct clock_event_device clockevent_mxc = {
254 .name = "mxc_timer1",
255 .features = CLOCK_EVT_FEAT_ONESHOT,
257 .set_mode = mxc_set_mode,
258 .set_next_event = mx1_2_set_next_event,
262 static int __init mxc_clockevent_init(struct clk *timer_clk)
264 unsigned int c = clk_get_rate(timer_clk);
267 clockevent_mxc.set_next_event = v2_set_next_event;
269 clockevent_mxc.mult = div_sc(c, NSEC_PER_SEC,
270 clockevent_mxc.shift);
271 clockevent_mxc.max_delta_ns =
272 clockevent_delta2ns(0xfffffffe, &clockevent_mxc);
273 clockevent_mxc.min_delta_ns =
274 clockevent_delta2ns(0xff, &clockevent_mxc);
276 clockevent_mxc.cpumask = cpumask_of(0);
278 clockevents_register_device(&clockevent_mxc);
283 void __init mxc_timer_init(struct clk *timer_clk, void __iomem *base, int irq)
286 struct clk *timer_ipg_clk;
289 timer_clk = clk_get_sys("imx-gpt.0", "per");
290 if (IS_ERR(timer_clk)) {
291 pr_err("i.MX timer: unable to get clk\n");
295 timer_ipg_clk = clk_get_sys("imx-gpt.0", "ipg");
296 if (!IS_ERR(timer_ipg_clk))
297 clk_prepare_enable(timer_ipg_clk);
300 clk_prepare_enable(timer_clk);
305 * Initialise to a known state (all timers off, and timing reset)
308 __raw_writel(0, timer_base + MXC_TCTL);
309 __raw_writel(0, timer_base + MXC_TPRER); /* see datasheet note */
312 tctl_val = V2_TCTL_CLK_IPG | V2_TCTL_FRR | V2_TCTL_WAITEN | MXC_TCTL_TEN;
314 tctl_val = MX1_2_TCTL_FRR | MX1_2_TCTL_CLK_PCLK1 | MXC_TCTL_TEN;
316 __raw_writel(tctl_val, timer_base + MXC_TCTL);
318 /* init and register the timer to the framework */
319 mxc_clocksource_init(timer_clk);
320 mxc_clockevent_init(timer_clk);
322 /* Make irqs happen */
323 setup_irq(irq, &mxc_timer_irq);