diff --git a/arch/x86/include/asm/tsc.h b/arch/x86/include/asm/tsc.h index 7428697c5b8df1d6856ca63fdda62cb047083f28..33b6365c22fed29b7081f637fd96b0b78a5c2162 100644 --- a/arch/x86/include/asm/tsc.h +++ b/arch/x86/include/asm/tsc.h @@ -35,7 +35,7 @@ extern void tsc_init(void); extern void mark_tsc_unstable(char *reason); extern int unsynchronized_tsc(void); extern int check_tsc_unstable(void); -extern int check_tsc_disabled(void); +extern unsigned long native_calibrate_cpu(void); extern unsigned long native_calibrate_tsc(void); extern unsigned long long native_sched_clock_from_tsc(u64 tsc); @@ -52,7 +52,6 @@ extern int notsc_setup(char *); extern void tsc_save_sched_clock_state(void); extern void tsc_restore_sched_clock_state(void); -/* MSR based TSC calibration for Intel Atom SoC platforms */ -unsigned long try_msr_calibrate_tsc(void); +unsigned long cpu_khz_from_msr(void); #endif /* _ASM_X86_TSC_H */ diff --git a/arch/x86/include/asm/x86_init.h b/arch/x86/include/asm/x86_init.h index 66c15a01667f66dc6095914bb96c9f092a56127d..6ba79317844138672dfe7de27254425e20630b5b 100644 --- a/arch/x86/include/asm/x86_init.h +++ b/arch/x86/include/asm/x86_init.h @@ -182,7 +182,8 @@ struct x86_legacy_features { /** * struct x86_platform_ops - platform specific runtime functions - * @calibrate_tsc: calibrate TSC + * @calibrate_cpu: calibrate CPU + * @calibrate_tsc: calibrate TSC, if different from CPU * @get_wallclock: get time from HW clock like RTC etc. * @set_wallclock: set time back to HW clock * @is_untracked_pat_range exclude from PAT logic @@ -201,6 +202,7 @@ struct x86_legacy_features { * semantics. */ struct x86_platform_ops { + unsigned long (*calibrate_cpu)(void); unsigned long (*calibrate_tsc)(void); void (*get_wallclock)(struct timespec *ts); int (*set_wallclock)(const struct timespec *ts); diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index 38ba6de56edec93badec52707045b0db3a189e0a..a804b5ab32d0c841edddc29ebd4ea966ab5c3c01 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -239,7 +239,7 @@ static inline unsigned long long cycles_2_ns(unsigned long long cyc) return ns; } -static void set_cyc2ns_scale(unsigned long cpu_khz, int cpu) +static void set_cyc2ns_scale(unsigned long khz, int cpu) { unsigned long long tsc_now, ns_now; struct cyc2ns_data *data; @@ -248,7 +248,7 @@ static void set_cyc2ns_scale(unsigned long cpu_khz, int cpu) local_irq_save(flags); sched_clock_idle_sleep_event(); - if (!cpu_khz) + if (!khz) goto done; data = cyc2ns_write_begin(cpu); @@ -261,7 +261,7 @@ static void set_cyc2ns_scale(unsigned long cpu_khz, int cpu) * time function is continuous; see the comment near struct * cyc2ns_data. */ - clocks_calc_mult_shift(&data->cyc2ns_mul, &data->cyc2ns_shift, cpu_khz, + clocks_calc_mult_shift(&data->cyc2ns_mul, &data->cyc2ns_shift, khz, NSEC_PER_MSEC, 0); /* @@ -335,12 +335,6 @@ int check_tsc_unstable(void) } EXPORT_SYMBOL_GPL(check_tsc_unstable); -int check_tsc_disabled(void) -{ - return tsc_disabled; -} -EXPORT_SYMBOL_GPL(check_tsc_disabled); - #ifdef CONFIG_X86_TSC int __init notsc_setup(char *str) { @@ -665,19 +659,77 @@ static unsigned long quick_pit_calibrate(void) } /** - * native_calibrate_tsc - calibrate the tsc on boot + * native_calibrate_tsc + * Determine TSC frequency via CPUID, else return 0. */ unsigned long native_calibrate_tsc(void) +{ + unsigned int eax_denominator, ebx_numerator, ecx_hz, edx; + unsigned int crystal_khz; + + if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL) + return 0; + + if (boot_cpu_data.cpuid_level < 0x15) + return 0; + + eax_denominator = ebx_numerator = ecx_hz = edx = 0; + + /* CPUID 15H TSC/Crystal ratio, plus optionally Crystal Hz */ + cpuid(0x15, &eax_denominator, &ebx_numerator, &ecx_hz, &edx); + + if (ebx_numerator == 0 || eax_denominator == 0) + return 0; + + crystal_khz = ecx_hz / 1000; + + if (crystal_khz == 0) { + switch (boot_cpu_data.x86_model) { + case 0x4E: /* SKL */ + case 0x5E: /* SKL */ + crystal_khz = 24000; /* 24.0 MHz */ + break; + case 0x5C: /* BXT */ + crystal_khz = 19200; /* 19.2 MHz */ + break; + } + } + + return crystal_khz * ebx_numerator / eax_denominator; +} + +static unsigned long cpu_khz_from_cpuid(void) +{ + unsigned int eax_base_mhz, ebx_max_mhz, ecx_bus_mhz, edx; + + if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL) + return 0; + + if (boot_cpu_data.cpuid_level < 0x16) + return 0; + + eax_base_mhz = ebx_max_mhz = ecx_bus_mhz = edx = 0; + + cpuid(0x16, &eax_base_mhz, &ebx_max_mhz, &ecx_bus_mhz, &edx); + + return eax_base_mhz * 1000; +} + +/** + * native_calibrate_cpu - calibrate the cpu on boot + */ +unsigned long native_calibrate_cpu(void) { u64 tsc1, tsc2, delta, ref1, ref2; unsigned long tsc_pit_min = ULONG_MAX, tsc_ref_min = ULONG_MAX; unsigned long flags, latch, ms, fast_calibrate; int hpet = is_hpet_enabled(), i, loopmin; - /* Calibrate TSC using MSR for Intel Atom SoCs */ - local_irq_save(flags); - fast_calibrate = try_msr_calibrate_tsc(); - local_irq_restore(flags); + fast_calibrate = cpu_khz_from_cpuid(); + if (fast_calibrate) + return fast_calibrate; + + fast_calibrate = cpu_khz_from_msr(); if (fast_calibrate) return fast_calibrate; @@ -837,8 +889,12 @@ int recalibrate_cpu_khz(void) if (!boot_cpu_has(X86_FEATURE_TSC)) return -ENODEV; + cpu_khz = x86_platform.calibrate_cpu(); tsc_khz = x86_platform.calibrate_tsc(); - cpu_khz = tsc_khz; + if (tsc_khz == 0) + tsc_khz = cpu_khz; + else if (abs(cpu_khz - tsc_khz) * 10 > tsc_khz) + cpu_khz = tsc_khz; cpu_data(0).loops_per_jiffy = cpufreq_scale(cpu_data(0).loops_per_jiffy, cpu_khz_old, cpu_khz); @@ -1244,8 +1300,18 @@ void __init tsc_init(void) return; } + cpu_khz = x86_platform.calibrate_cpu(); tsc_khz = x86_platform.calibrate_tsc(); - cpu_khz = tsc_khz; + + /* + * Trust non-zero tsc_khz as authorative, + * and use it to sanity check cpu_khz, + * which will be off if system timer is off. + */ + if (tsc_khz == 0) + tsc_khz = cpu_khz; + else if (abs(cpu_khz - tsc_khz) * 10 > tsc_khz) + cpu_khz = tsc_khz; if (!tsc_khz) { mark_tsc_unstable("could not calculate TSC khz"); @@ -1265,7 +1331,7 @@ void __init tsc_init(void) */ for_each_possible_cpu(cpu) { cyc2ns_init(cpu); - set_cyc2ns_scale(cpu_khz, cpu); + set_cyc2ns_scale(tsc_khz, cpu); } if (tsc_disabled > 0) diff --git a/arch/x86/kernel/tsc_msr.c b/arch/x86/kernel/tsc_msr.c index 9911a0620f9a94c1b6e1aa02290649d7c2803600..0fe720d64feff2c7027280f741495f6a9cf4722c 100644 --- a/arch/x86/kernel/tsc_msr.c +++ b/arch/x86/kernel/tsc_msr.c @@ -1,14 +1,5 @@ /* - * tsc_msr.c - MSR based TSC calibration on Intel Atom SoC platforms. - * - * TSC in Intel Atom SoC runs at a constant rate which can be figured - * by this formula: - * * - * See Intel 64 and IA-32 System Programming Guid section 16.12 and 30.11.5 - * for details. - * Especially some Intel Atom SoCs don't have PIT(i8254) or HPET, so MSR - * based calibration is the only option. - * + * tsc_msr.c - TSC frequency enumeration via MSR * * Copyright (C) 2013 Intel Corporation * Author: Bin Gao @@ -22,18 +13,10 @@ #include #include -/* CPU reference clock frequency: in KHz */ -#define FREQ_80 80000 -#define FREQ_83 83200 -#define FREQ_100 99840 -#define FREQ_133 133200 -#define FREQ_166 166400 - -#define MAX_NUM_FREQS 8 +#define MAX_NUM_FREQS 9 /* - * According to Intel 64 and IA-32 System Programming Guide, - * if MSR_PERF_STAT[31] is set, the maximum resolved bus ratio can be + * If MSR_PERF_STAT[31] is set, the maximum resolved bus ratio can be * read in MSR_PLATFORM_ID[12:8], otherwise in MSR_PERF_STAT[44:40]. * Unfortunately some Intel Atom SoCs aren't quite compliant to this, * so we need manually differentiate SoC families. This is what the @@ -48,17 +31,18 @@ struct freq_desc { static struct freq_desc freq_desc_tables[] = { /* PNW */ - { 6, 0x27, 0, { 0, 0, 0, 0, 0, FREQ_100, 0, FREQ_83 } }, + { 6, 0x27, 0, { 0, 0, 0, 0, 0, 99840, 0, 83200 } }, /* CLV+ */ - { 6, 0x35, 0, { 0, FREQ_133, 0, 0, 0, FREQ_100, 0, FREQ_83 } }, - /* TNG */ - { 6, 0x4a, 1, { 0, FREQ_100, FREQ_133, 0, 0, 0, 0, 0 } }, - /* VLV2 */ - { 6, 0x37, 1, { FREQ_83, FREQ_100, FREQ_133, FREQ_166, 0, 0, 0, 0 } }, - /* ANN */ - { 6, 0x5a, 1, { FREQ_83, FREQ_100, FREQ_133, FREQ_100, 0, 0, 0, 0 } }, - /* AIRMONT */ - { 6, 0x4c, 1, { FREQ_83, FREQ_100, FREQ_133, FREQ_166, FREQ_80, 0, 0, 0 } }, + { 6, 0x35, 0, { 0, 133200, 0, 0, 0, 99840, 0, 83200 } }, + /* TNG - Intel Atom processor Z3400 series */ + { 6, 0x4a, 1, { 0, 100000, 133300, 0, 0, 0, 0, 0 } }, + /* VLV2 - Intel Atom processor E3000, Z3600, Z3700 series */ + { 6, 0x37, 1, { 83300, 100000, 133300, 116700, 80000, 0, 0, 0 } }, + /* ANN - Intel Atom processor Z3500 series */ + { 6, 0x5a, 1, { 83300, 100000, 133300, 100000, 0, 0, 0, 0 } }, + /* AMT - Intel Atom processor X7-Z8000 and X5-Z8000 series */ + { 6, 0x4c, 1, { 83300, 100000, 133300, 116700, + 80000, 93300, 90000, 88900, 87500 } }, }; static int match_cpu(u8 family, u8 model) @@ -79,16 +63,20 @@ static int match_cpu(u8 family, u8 model) (freq_desc_tables[cpu_index].freqs[freq_id]) /* - * Do MSR calibration only for known/supported CPUs. + * MSR-based CPU/TSC frequency discovery for certain CPUs. * - * Returns the calibration value or 0 if MSR calibration failed. + * Set global "lapic_timer_frequency" to bus_clock_cycles/jiffy + * Return processor base frequency in KHz, or 0 on failure. */ -unsigned long try_msr_calibrate_tsc(void) +unsigned long cpu_khz_from_msr(void) { u32 lo, hi, ratio, freq_id, freq; unsigned long res; int cpu_index; + if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL) + return 0; + cpu_index = match_cpu(boot_cpu_data.x86, boot_cpu_data.x86_model); if (cpu_index < 0) return 0; @@ -100,31 +88,17 @@ unsigned long try_msr_calibrate_tsc(void) rdmsr(MSR_IA32_PERF_STATUS, lo, hi); ratio = (hi >> 8) & 0x1f; } - pr_info("Maximum core-clock to bus-clock ratio: 0x%x\n", ratio); - - if (!ratio) - goto fail; /* Get FSB FREQ ID */ rdmsr(MSR_FSB_FREQ, lo, hi); freq_id = lo & 0x7; freq = id_to_freq(cpu_index, freq_id); - pr_info("Resolved frequency ID: %u, frequency: %u KHz\n", - freq_id, freq); - if (!freq) - goto fail; /* TSC frequency = maximum resolved freq * maximum resolved bus ratio */ res = freq * ratio; - pr_info("TSC runs at %lu KHz\n", res); #ifdef CONFIG_X86_LOCAL_APIC lapic_timer_frequency = (freq * 1000) / HZ; - pr_info("lapic_timer_frequency = %d\n", lapic_timer_frequency); #endif return res; - -fail: - pr_warn("Fast TSC calibration using MSR failed\n"); - return 0; } diff --git a/arch/x86/kernel/x86_init.c b/arch/x86/kernel/x86_init.c index dad5fe9633a37e03215892c60386a779745fdb61..58b459296e13d007655e3ba8854d11832a535154 100644 --- a/arch/x86/kernel/x86_init.c +++ b/arch/x86/kernel/x86_init.c @@ -92,6 +92,7 @@ static void default_nmi_init(void) { }; static int default_i8042_detect(void) { return 1; }; struct x86_platform_ops x86_platform = { + .calibrate_cpu = native_calibrate_cpu, .calibrate_tsc = native_calibrate_tsc, .get_wallclock = mach_get_cmos_time, .set_wallclock = mach_set_rtc_mmss,