/* * mfld.c: Intel Medfield platform setup code * * (C) Copyright 2013 Intel Corporation * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; version 2 * of the License. */ #include #include #include #include #include "intel_mid_weak_decls.h" static unsigned long __init mfld_calibrate_tsc(void) { unsigned long fast_calibrate; u32 lo, hi, ratio, fsb; rdmsr(MSR_IA32_PERF_STATUS, lo, hi); pr_debug("IA32 perf status is 0x%x, 0x%0x\n", lo, hi); ratio = (hi >> 8) & 0x1f; pr_debug("ratio is %d\n", ratio); if (!ratio) { pr_err("read a zero ratio, should be incorrect!\n"); pr_err("force tsc ratio to 16 ...\n"); ratio = 16; } rdmsr(MSR_FSB_FREQ, lo, hi); if ((lo & 0x7) == 0x7) fsb = FSB_FREQ_83SKU; else fsb = FSB_FREQ_100SKU; fast_calibrate = ratio * fsb; pr_debug("read penwell tsc %lu khz\n", fast_calibrate); lapic_timer_frequency = fsb * 1000 / HZ; /* * TSC on Intel Atom SoCs is reliable and of known frequency. * See tsc_msr.c for details. */ setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ); setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE); return fast_calibrate; } static void __init penwell_arch_setup(void) { x86_platform.calibrate_tsc = mfld_calibrate_tsc; } static struct intel_mid_ops penwell_ops = { .arch_setup = penwell_arch_setup, }; void *get_penwell_ops(void) { return &penwell_ops; } void *get_cloverview_ops(void) { return &penwell_ops; }