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c4a0208f KW |
1 | /* |
2 | * arch/arm/mach-lpc32xx/timer.c | |
3 | * | |
4 | * Author: Kevin Wells <kevin.wells@nxp.com> | |
5 | * | |
6 | * Copyright (C) 2009 - 2010 NXP Semiconductors | |
7 | * Copyright (C) 2009 Fontys University of Applied Sciences, Eindhoven | |
8 | * Ed Schouten <e.schouten@fontys.nl> | |
9 | * Laurens Timmermans <l.timmermans@fontys.nl> | |
10 | * | |
11 | * This program is free software; you can redistribute it and/or modify | |
12 | * it under the terms of the GNU General Public License as published by | |
13 | * the Free Software Foundation; either version 2 of the License, or | |
14 | * (at your option) any later version. | |
15 | * | |
16 | * This program is distributed in the hope that it will be useful, | |
17 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
18 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
19 | * GNU General Public License for more details. | |
20 | */ | |
21 | ||
22 | #include <linux/interrupt.h> | |
23 | #include <linux/irq.h> | |
24 | #include <linux/time.h> | |
25 | #include <linux/err.h> | |
26 | #include <linux/clockchips.h> | |
27 | ||
28 | #include <asm/mach/time.h> | |
29 | ||
30 | #include <mach/hardware.h> | |
31 | #include <mach/platform.h> | |
32 | #include "common.h" | |
33 | ||
c4a0208f KW |
34 | static int lpc32xx_clkevt_next_event(unsigned long delta, |
35 | struct clock_event_device *dev) | |
36 | { | |
37 | __raw_writel(LCP32XX_TIMER_CNTR_TCR_RESET, | |
38 | LCP32XX_TIMER_TCR(LPC32XX_TIMER0_BASE)); | |
39 | __raw_writel(delta, LCP32XX_TIMER_PR(LPC32XX_TIMER0_BASE)); | |
40 | __raw_writel(LCP32XX_TIMER_CNTR_TCR_EN, | |
41 | LCP32XX_TIMER_TCR(LPC32XX_TIMER0_BASE)); | |
42 | ||
43 | return 0; | |
44 | } | |
45 | ||
46 | static void lpc32xx_clkevt_mode(enum clock_event_mode mode, | |
47 | struct clock_event_device *dev) | |
48 | { | |
49 | switch (mode) { | |
50 | case CLOCK_EVT_MODE_PERIODIC: | |
51 | WARN_ON(1); | |
52 | break; | |
53 | ||
54 | case CLOCK_EVT_MODE_ONESHOT: | |
55 | case CLOCK_EVT_MODE_SHUTDOWN: | |
56 | /* | |
57 | * Disable the timer. When using oneshot, we must also | |
58 | * disable the timer to wait for the first call to | |
59 | * set_next_event(). | |
60 | */ | |
61 | __raw_writel(0, LCP32XX_TIMER_TCR(LPC32XX_TIMER0_BASE)); | |
62 | break; | |
63 | ||
64 | case CLOCK_EVT_MODE_UNUSED: | |
65 | case CLOCK_EVT_MODE_RESUME: | |
66 | break; | |
67 | } | |
68 | } | |
69 | ||
70 | static struct clock_event_device lpc32xx_clkevt = { | |
71 | .name = "lpc32xx_clkevt", | |
72 | .features = CLOCK_EVT_FEAT_ONESHOT, | |
73 | .shift = 32, | |
74 | .rating = 300, | |
75 | .set_next_event = lpc32xx_clkevt_next_event, | |
76 | .set_mode = lpc32xx_clkevt_mode, | |
77 | }; | |
78 | ||
79 | static irqreturn_t lpc32xx_timer_interrupt(int irq, void *dev_id) | |
80 | { | |
81 | struct clock_event_device *evt = &lpc32xx_clkevt; | |
82 | ||
83 | /* Clear match */ | |
84 | __raw_writel(LCP32XX_TIMER_CNTR_MTCH_BIT(0), | |
85 | LCP32XX_TIMER_IR(LPC32XX_TIMER0_BASE)); | |
86 | ||
87 | evt->event_handler(evt); | |
88 | ||
89 | return IRQ_HANDLED; | |
90 | } | |
91 | ||
92 | static struct irqaction lpc32xx_timer_irq = { | |
93 | .name = "LPC32XX Timer Tick", | |
94 | .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL, | |
95 | .handler = lpc32xx_timer_interrupt, | |
96 | }; | |
97 | ||
98 | /* | |
99 | * The clock management driver isn't initialized at this point, so the | |
100 | * clocks need to be enabled here manually and then tagged as used in | |
101 | * the clock driver initialization | |
102 | */ | |
103 | static void __init lpc32xx_timer_init(void) | |
104 | { | |
105 | u32 clkrate, pllreg; | |
106 | ||
107 | /* Enable timer clock */ | |
108 | __raw_writel(LPC32XX_CLKPWR_TMRPWMCLK_TIMER0_EN | | |
109 | LPC32XX_CLKPWR_TMRPWMCLK_TIMER1_EN, | |
110 | LPC32XX_CLKPWR_TIMERS_PWMS_CLK_CTRL_1); | |
111 | ||
112 | /* | |
113 | * The clock driver isn't initialized at this point. So determine if | |
114 | * the SYSCLK is driven from the PLL397 or main oscillator and then use | |
115 | * it to compute the PLL frequency and the PCLK divider to get the base | |
116 | * timer rates. This rate is needed to compute the tick rate. | |
117 | */ | |
118 | if (clk_is_sysclk_mainosc() != 0) | |
119 | clkrate = LPC32XX_MAIN_OSC_FREQ; | |
120 | else | |
121 | clkrate = 397 * LPC32XX_CLOCK_OSC_FREQ; | |
122 | ||
123 | /* Get ARM HCLKPLL register and convert it into a frequency */ | |
124 | pllreg = __raw_readl(LPC32XX_CLKPWR_HCLKPLL_CTRL) & 0x1FFFF; | |
125 | clkrate = clk_get_pllrate_from_reg(clkrate, pllreg); | |
126 | ||
127 | /* Get PCLK divider and divide ARM PLL clock by it to get timer rate */ | |
128 | clkrate = clkrate / clk_get_pclk_div(); | |
129 | ||
130 | /* Initial timer setup */ | |
131 | __raw_writel(0, LCP32XX_TIMER_TCR(LPC32XX_TIMER0_BASE)); | |
132 | __raw_writel(LCP32XX_TIMER_CNTR_MTCH_BIT(0), | |
133 | LCP32XX_TIMER_IR(LPC32XX_TIMER0_BASE)); | |
134 | __raw_writel(1, LCP32XX_TIMER_MR0(LPC32XX_TIMER0_BASE)); | |
135 | __raw_writel(LCP32XX_TIMER_CNTR_MCR_MTCH(0) | | |
136 | LCP32XX_TIMER_CNTR_MCR_STOP(0) | | |
137 | LCP32XX_TIMER_CNTR_MCR_RESET(0), | |
138 | LCP32XX_TIMER_MCR(LPC32XX_TIMER0_BASE)); | |
139 | ||
140 | /* Setup tick interrupt */ | |
141 | setup_irq(IRQ_LPC32XX_TIMER0, &lpc32xx_timer_irq); | |
142 | ||
143 | /* Setup the clockevent structure. */ | |
144 | lpc32xx_clkevt.mult = div_sc(clkrate, NSEC_PER_SEC, | |
145 | lpc32xx_clkevt.shift); | |
146 | lpc32xx_clkevt.max_delta_ns = clockevent_delta2ns(-1, | |
147 | &lpc32xx_clkevt); | |
148 | lpc32xx_clkevt.min_delta_ns = clockevent_delta2ns(1, | |
149 | &lpc32xx_clkevt) + 1; | |
150 | lpc32xx_clkevt.cpumask = cpumask_of(0); | |
151 | clockevents_register_device(&lpc32xx_clkevt); | |
152 | ||
153 | /* Use timer1 as clock source. */ | |
154 | __raw_writel(LCP32XX_TIMER_CNTR_TCR_RESET, | |
155 | LCP32XX_TIMER_TCR(LPC32XX_TIMER1_BASE)); | |
156 | __raw_writel(0, LCP32XX_TIMER_PR(LPC32XX_TIMER1_BASE)); | |
157 | __raw_writel(0, LCP32XX_TIMER_MCR(LPC32XX_TIMER1_BASE)); | |
158 | __raw_writel(LCP32XX_TIMER_CNTR_TCR_EN, | |
159 | LCP32XX_TIMER_TCR(LPC32XX_TIMER1_BASE)); | |
234b6ced RK |
160 | |
161 | clocksource_mmio_init(LCP32XX_TIMER_TC(LPC32XX_TIMER1_BASE), | |
162 | "lpc32xx_clksrc", clkrate, 300, 32, clocksource_mmio_readl_up); | |
c4a0208f KW |
163 | } |
164 | ||
165 | struct sys_timer lpc32xx_timer = { | |
166 | .init = &lpc32xx_timer_init, | |
167 | }; | |
168 |