| Steven J. Hill | 3070033 | 2012-05-30 21:02:49 +0000 | [diff] [blame] | 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 | } |