diff options
| -rw-r--r-- | arch/blackfin/kernel/time-ts.c | 35 |
1 files changed, 2 insertions, 33 deletions
diff --git a/arch/blackfin/kernel/time-ts.c b/arch/blackfin/kernel/time-ts.c index 8c9a43daf80f..4a013714500b 100644 --- a/arch/blackfin/kernel/time-ts.c +++ b/arch/blackfin/kernel/time-ts.c | |||
| @@ -23,29 +23,6 @@ | |||
| 23 | #include <asm/gptimers.h> | 23 | #include <asm/gptimers.h> |
| 24 | #include <asm/nmi.h> | 24 | #include <asm/nmi.h> |
| 25 | 25 | ||
| 26 | /* Accelerators for sched_clock() | ||
| 27 | * convert from cycles(64bits) => nanoseconds (64bits) | ||
| 28 | * basic equation: | ||
| 29 | * ns = cycles / (freq / ns_per_sec) | ||
| 30 | * ns = cycles * (ns_per_sec / freq) | ||
| 31 | * ns = cycles * (10^9 / (cpu_khz * 10^3)) | ||
| 32 | * ns = cycles * (10^6 / cpu_khz) | ||
| 33 | * | ||
| 34 | * Then we use scaling math (suggested by george@mvista.com) to get: | ||
| 35 | * ns = cycles * (10^6 * SC / cpu_khz) / SC | ||
| 36 | * ns = cycles * cyc2ns_scale / SC | ||
| 37 | * | ||
| 38 | * And since SC is a constant power of two, we can convert the div | ||
| 39 | * into a shift. | ||
| 40 | * | ||
| 41 | * We can use khz divisor instead of mhz to keep a better precision, since | ||
| 42 | * cyc2ns_scale is limited to 10^6 * 2^10, which fits in 32 bits. | ||
| 43 | * (mathieu.desnoyers@polymtl.ca) | ||
| 44 | * | ||
| 45 | * -johnstul@us.ibm.com "math is hard, lets go shopping!" | ||
| 46 | */ | ||
| 47 | |||
| 48 | #define CYC2NS_SCALE_FACTOR 10 /* 2^10, carefully chosen */ | ||
| 49 | 26 | ||
| 50 | #if defined(CONFIG_CYCLES_CLOCKSOURCE) | 27 | #if defined(CONFIG_CYCLES_CLOCKSOURCE) |
| 51 | 28 | ||
| @@ -63,7 +40,6 @@ static struct clocksource bfin_cs_cycles = { | |||
| 63 | .rating = 400, | 40 | .rating = 400, |
| 64 | .read = bfin_read_cycles, | 41 | .read = bfin_read_cycles, |
| 65 | .mask = CLOCKSOURCE_MASK(64), | 42 | .mask = CLOCKSOURCE_MASK(64), |
| 66 | .shift = CYC2NS_SCALE_FACTOR, | ||
| 67 | .flags = CLOCK_SOURCE_IS_CONTINUOUS, | 43 | .flags = CLOCK_SOURCE_IS_CONTINUOUS, |
| 68 | }; | 44 | }; |
| 69 | 45 | ||
| @@ -75,10 +51,7 @@ static inline unsigned long long bfin_cs_cycles_sched_clock(void) | |||
| 75 | 51 | ||
| 76 | static int __init bfin_cs_cycles_init(void) | 52 | static int __init bfin_cs_cycles_init(void) |
| 77 | { | 53 | { |
| 78 | bfin_cs_cycles.mult = \ | 54 | if (clocksource_register_hz(&bfin_cs_cycles, get_cclk())) |
| 79 | clocksource_hz2mult(get_cclk(), bfin_cs_cycles.shift); | ||
| 80 | |||
| 81 | if (clocksource_register(&bfin_cs_cycles)) | ||
| 82 | panic("failed to register clocksource"); | 55 | panic("failed to register clocksource"); |
| 83 | 56 | ||
| 84 | return 0; | 57 | return 0; |
| @@ -111,7 +84,6 @@ static struct clocksource bfin_cs_gptimer0 = { | |||
| 111 | .rating = 350, | 84 | .rating = 350, |
| 112 | .read = bfin_read_gptimer0, | 85 | .read = bfin_read_gptimer0, |
| 113 | .mask = CLOCKSOURCE_MASK(32), | 86 | .mask = CLOCKSOURCE_MASK(32), |
| 114 | .shift = CYC2NS_SCALE_FACTOR, | ||
| 115 | .flags = CLOCK_SOURCE_IS_CONTINUOUS, | 87 | .flags = CLOCK_SOURCE_IS_CONTINUOUS, |
| 116 | }; | 88 | }; |
| 117 | 89 | ||
| @@ -125,10 +97,7 @@ static int __init bfin_cs_gptimer0_init(void) | |||
| 125 | { | 97 | { |
| 126 | setup_gptimer0(); | 98 | setup_gptimer0(); |
| 127 | 99 | ||
| 128 | bfin_cs_gptimer0.mult = \ | 100 | if (clocksource_register_hz(&bfin_cs_gptimer0, get_sclk())) |
| 129 | clocksource_hz2mult(get_sclk(), bfin_cs_gptimer0.shift); | ||
| 130 | |||
| 131 | if (clocksource_register(&bfin_cs_gptimer0)) | ||
| 132 | panic("failed to register clocksource"); | 101 | panic("failed to register clocksource"); |
| 133 | 102 | ||
| 134 | return 0; | 103 | return 0; |
