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3070033a SH |
1 | /* |
2 | * This file is subject to the terms and conditions of the GNU General Public | |
3 | * License. See the file "COPYING" in the main directory of this archive | |
4 | * for more details. | |
5 | * | |
6 | * Copyright (C) 2012 MIPS Technologies, Inc. All rights reserved. | |
7 | */ | |
8 | #include <linux/init.h> | |
9 | ||
10 | #include <asm/setup.h> | |
11 | #include <asm/time.h> | |
12 | #include <asm/irq.h> | |
13 | #include <asm/mips-boards/generic.h> | |
14 | #include <asm/mips-boards/prom.h> | |
15 | ||
16 | unsigned long cpu_khz; | |
17 | ||
18 | static int mips_cpu_timer_irq; | |
19 | static int mips_cpu_perf_irq; | |
20 | ||
21 | static void mips_timer_dispatch(void) | |
22 | { | |
23 | do_IRQ(mips_cpu_timer_irq); | |
24 | } | |
25 | ||
26 | static void mips_perf_dispatch(void) | |
27 | { | |
28 | do_IRQ(mips_cpu_perf_irq); | |
29 | } | |
30 | ||
31 | static void __iomem *status_reg = (void __iomem *)0xbf000410; | |
32 | ||
33 | /* | |
34 | * Estimate CPU frequency. Sets mips_hpt_frequency as a side-effect. | |
35 | */ | |
36 | static unsigned int __init estimate_cpu_frequency(void) | |
37 | { | |
38 | unsigned int prid = read_c0_prid() & 0xffff00; | |
39 | unsigned int tick = 0; | |
40 | unsigned int freq; | |
41 | unsigned int orig; | |
42 | unsigned long flags; | |
43 | ||
44 | local_irq_save(flags); | |
45 | ||
46 | orig = readl(status_reg) & 0x2; /* get original sample */ | |
47 | /* wait for transition */ | |
48 | while ((readl(status_reg) & 0x2) == orig) | |
49 | ; | |
50 | orig = orig ^ 0x2; /* flip the bit */ | |
51 | ||
52 | write_c0_count(0); | |
53 | ||
54 | /* wait 1 second (the sampling clock transitions every 10ms) */ | |
55 | while (tick < 100) { | |
56 | /* wait for transition */ | |
57 | while ((readl(status_reg) & 0x2) == orig) | |
58 | ; | |
59 | orig = orig ^ 0x2; /* flip the bit */ | |
60 | tick++; | |
61 | } | |
62 | ||
63 | freq = read_c0_count(); | |
64 | ||
65 | local_irq_restore(flags); | |
66 | ||
67 | mips_hpt_frequency = freq; | |
68 | ||
69 | /* Adjust for processor */ | |
70 | if ((prid != (PRID_COMP_MIPS | PRID_IMP_20KC)) && | |
71 | (prid != (PRID_COMP_MIPS | PRID_IMP_25KF))) | |
72 | freq *= 2; | |
73 | ||
74 | freq += 5000; /* rounding */ | |
75 | freq -= freq%10000; | |
76 | ||
77 | return freq ; | |
78 | } | |
79 | ||
80 | void read_persistent_clock(struct timespec *ts) | |
81 | { | |
82 | ts->tv_sec = 0; | |
83 | ts->tv_nsec = 0; | |
84 | } | |
85 | ||
86 | static void __init plat_perf_setup(void) | |
87 | { | |
88 | if (cp0_perfcount_irq >= 0) { | |
89 | if (cpu_has_vint) | |
90 | set_vi_handler(cp0_perfcount_irq, mips_perf_dispatch); | |
91 | mips_cpu_perf_irq = MIPS_CPU_IRQ_BASE + cp0_perfcount_irq; | |
92 | } | |
93 | } | |
94 | ||
95 | unsigned int __cpuinit get_c0_compare_int(void) | |
96 | { | |
97 | if (cpu_has_vint) | |
98 | set_vi_handler(cp0_compare_irq, mips_timer_dispatch); | |
99 | mips_cpu_timer_irq = MIPS_CPU_IRQ_BASE + cp0_compare_irq; | |
100 | return mips_cpu_timer_irq; | |
101 | } | |
102 | ||
103 | void __init plat_time_init(void) | |
104 | { | |
105 | unsigned int est_freq; | |
106 | ||
107 | est_freq = estimate_cpu_frequency(); | |
108 | ||
109 | pr_debug("CPU frequency %d.%02d MHz\n", (est_freq / 1000000), | |
110 | (est_freq % 1000000) * 100 / 1000000); | |
111 | ||
112 | cpu_khz = est_freq / 1000; | |
113 | ||
114 | mips_scroll_message(); | |
115 | ||
116 | plat_perf_setup(); | |
117 | } |