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ea49f8ff PDM |
1 | /***************************************************************************/ |
2 | ||
3 | /* | |
4 | * sltimers.c -- generic ColdFire slice timer support. | |
5 | * | |
6 | * Copyright (C) 2009-2010, Philippe De Muyter <phdm@macqel.be> | |
7 | * based on | |
8 | * timers.c -- generic ColdFire hardware timer support. | |
9 | * Copyright (C) 1999-2008, Greg Ungerer <gerg@snapgear.com> | |
10 | */ | |
11 | ||
12 | /***************************************************************************/ | |
13 | ||
14 | #include <linux/kernel.h> | |
15 | #include <linux/init.h> | |
16 | #include <linux/sched.h> | |
17 | #include <linux/interrupt.h> | |
18 | #include <linux/irq.h> | |
19 | #include <linux/profile.h> | |
20 | #include <linux/clocksource.h> | |
21 | #include <asm/io.h> | |
22 | #include <asm/traps.h> | |
23 | #include <asm/machdep.h> | |
24 | #include <asm/coldfire.h> | |
25 | #include <asm/mcfslt.h> | |
26 | #include <asm/mcfsim.h> | |
27 | ||
28 | /***************************************************************************/ | |
29 | ||
30 | #ifdef CONFIG_HIGHPROFILE | |
31 | ||
32 | /* | |
33 | * By default use Slice Timer 1 as the profiler clock timer. | |
34 | */ | |
35 | #define PA(a) (MCF_MBAR + MCFSLT_TIMER1 + (a)) | |
36 | ||
37 | /* | |
38 | * Choose a reasonably fast profile timer. Make it an odd value to | |
39 | * try and get good coverage of kernel operations. | |
40 | */ | |
41 | #define PROFILEHZ 1013 | |
42 | ||
43 | irqreturn_t mcfslt_profile_tick(int irq, void *dummy) | |
44 | { | |
45 | /* Reset Slice Timer 1 */ | |
46 | __raw_writel(MCFSLT_SSR_BE | MCFSLT_SSR_TE, PA(MCFSLT_SSR)); | |
47 | if (current->pid) | |
48 | profile_tick(CPU_PROFILING); | |
49 | return IRQ_HANDLED; | |
50 | } | |
51 | ||
52 | static struct irqaction mcfslt_profile_irq = { | |
53 | .name = "profile timer", | |
54 | .flags = IRQF_DISABLED | IRQF_TIMER, | |
55 | .handler = mcfslt_profile_tick, | |
56 | }; | |
57 | ||
58 | void mcfslt_profile_init(void) | |
59 | { | |
60 | printk(KERN_INFO "PROFILE: lodging TIMER 1 @ %dHz as profile timer\n", | |
61 | PROFILEHZ); | |
62 | ||
63 | setup_irq(MCF_IRQ_PROFILER, &mcfslt_profile_irq); | |
64 | ||
65 | /* Set up TIMER 2 as high speed profile clock */ | |
66 | __raw_writel(MCF_BUSCLK / PROFILEHZ - 1, PA(MCFSLT_STCNT)); | |
67 | __raw_writel(MCFSLT_SCR_RUN | MCFSLT_SCR_IEN | MCFSLT_SCR_TEN, | |
68 | PA(MCFSLT_SCR)); | |
69 | ||
70 | } | |
71 | ||
72 | #endif /* CONFIG_HIGHPROFILE */ | |
73 | ||
74 | /***************************************************************************/ | |
75 | ||
76 | /* | |
77 | * By default use Slice Timer 0 as the system clock timer. | |
78 | */ | |
79 | #define TA(a) (MCF_MBAR + MCFSLT_TIMER0 + (a)) | |
80 | ||
81 | static u32 mcfslt_cycles_per_jiffy; | |
82 | static u32 mcfslt_cnt; | |
83 | ||
84 | static irqreturn_t mcfslt_tick(int irq, void *dummy) | |
85 | { | |
86 | /* Reset Slice Timer 0 */ | |
87 | __raw_writel(MCFSLT_SSR_BE | MCFSLT_SSR_TE, TA(MCFSLT_SSR)); | |
88 | mcfslt_cnt += mcfslt_cycles_per_jiffy; | |
89 | return arch_timer_interrupt(irq, dummy); | |
90 | } | |
91 | ||
92 | static struct irqaction mcfslt_timer_irq = { | |
93 | .name = "timer", | |
94 | .flags = IRQF_DISABLED | IRQF_TIMER, | |
95 | .handler = mcfslt_tick, | |
96 | }; | |
97 | ||
98 | static cycle_t mcfslt_read_clk(struct clocksource *cs) | |
99 | { | |
100 | unsigned long flags; | |
101 | u32 cycles; | |
102 | u16 scnt; | |
103 | ||
104 | local_irq_save(flags); | |
105 | scnt = __raw_readl(TA(MCFSLT_SCNT)); | |
106 | cycles = mcfslt_cnt; | |
107 | local_irq_restore(flags); | |
108 | ||
25985edc | 109 | /* subtract because slice timers count down */ |
ea49f8ff PDM |
110 | return cycles - scnt; |
111 | } | |
112 | ||
113 | static struct clocksource mcfslt_clk = { | |
114 | .name = "slt", | |
115 | .rating = 250, | |
116 | .read = mcfslt_read_clk, | |
117 | .shift = 20, | |
118 | .mask = CLOCKSOURCE_MASK(32), | |
119 | .flags = CLOCK_SOURCE_IS_CONTINUOUS, | |
120 | }; | |
121 | ||
122 | void hw_timer_init(void) | |
123 | { | |
124 | mcfslt_cycles_per_jiffy = MCF_BUSCLK / HZ; | |
125 | /* | |
126 | * The coldfire slice timer (SLT) runs from STCNT to 0 included, | |
127 | * then STCNT again and so on. It counts thus actually | |
128 | * STCNT + 1 steps for 1 tick, not STCNT. So if you want | |
129 | * n cycles, initialize STCNT with n - 1. | |
130 | */ | |
131 | __raw_writel(mcfslt_cycles_per_jiffy - 1, TA(MCFSLT_STCNT)); | |
132 | __raw_writel(MCFSLT_SCR_RUN | MCFSLT_SCR_IEN | MCFSLT_SCR_TEN, | |
133 | TA(MCFSLT_SCR)); | |
134 | /* initialize mcfslt_cnt knowing that slice timers count down */ | |
135 | mcfslt_cnt = mcfslt_cycles_per_jiffy; | |
136 | ||
137 | setup_irq(MCF_IRQ_TIMER, &mcfslt_timer_irq); | |
138 | ||
139 | mcfslt_clk.mult = clocksource_hz2mult(MCF_BUSCLK, mcfslt_clk.shift); | |
140 | clocksource_register(&mcfslt_clk); | |
141 | ||
142 | #ifdef CONFIG_HIGHPROFILE | |
143 | mcfslt_profile_init(); | |
144 | #endif | |
145 | } |