Hi Bin, On 11 November 2014 18:16, Bin Meng <bmeng...@gmail.com> wrote: > Hi Simon, > > On Wed, Nov 12, 2014 at 12:10 AM, Simon Glass <s...@chromium.org> wrote: >> Hi Bin, >> >> On 11 November 2014 01:25, Bin Meng <bmeng...@gmail.com> wrote: >>> Hi Simon, >>> >>> On Tue, Nov 11, 2014 at 2:54 AM, Simon Glass <s...@chromium.org> wrote: >>>> Hi Bin, >>>> >>>> On 9 November 2014 07:19, Bin Meng <bmeng...@gmail.com> wrote: >>>>> Using MSR_PLATFORM_INFO (0xCE) to calibrate TSR will cause #GP on >>>>> processors which do not have this MSR. Instead only doing the MSR >>>>> calibration for known/supported CPUs. >>>>> >>>>> Signed-off-by: Bin Meng <bmeng...@gmail.com> >>>>> Acked-by: Simon Glass <s...@chromium.org> >>>>> Tested-by: Simon Glass <s...@chromium.org> >>>>> --- >>>>> arch/x86/lib/tsc_timer.c | 116 >>>>> ++++++++++++++++++++++++++++++++++++++++++++--- >>>>> 1 file changed, 109 insertions(+), 7 deletions(-) >>>> >>>> Applied to u-boot-x86/master, thanks! >>>> >>>> (Please see note below) >>>> >>>>> >>>>> diff --git a/arch/x86/lib/tsc_timer.c b/arch/x86/lib/tsc_timer.c >>>>> index 8b38702..fafbbfc 100644 >>>>> --- a/arch/x86/lib/tsc_timer.c >>>>> +++ b/arch/x86/lib/tsc_timer.c >>>>> @@ -1,6 +1,9 @@ >>>>> /* >>>>> * Copyright (c) 2012 The Chromium OS Authors. >>>>> * >>>>> + * TSC calibration codes are adapted from Linux kernel >>>>> + * arch/x86/kernel/tsc_msr.c and arch/x86/kernel/tsc.c >>>>> + * >>>>> * SPDX-License-Identifier: GPL-2.0+ >>>>> */ >>>>> >>>>> @@ -12,8 +15,108 @@ >>>>> #include <asm/msr.h> >>>>> #include <asm/u-boot-x86.h> >>>>> >>>>> +/* CPU reference clock frequency: in KHz */ >>>>> +#define FREQ_83 83200 >>>>> +#define FREQ_100 99840 >>>>> +#define FREQ_133 133200 >>>>> +#define FREQ_166 166400 >>>>> + >>>>> +#define MAX_NUM_FREQS 8 >>>>> + >>>>> DECLARE_GLOBAL_DATA_PTR; >>>>> >>>>> +/* >>>>> + * According to Intel 64 and IA-32 System Programming Guide, >>>>> + * 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 >>>>> + * field msr_plat does. >>>>> + */ >>>>> +struct freq_desc { >>>>> + u8 x86_family; /* CPU family */ >>>>> + u8 x86_model; /* model */ >>>>> + u8 msr_plat; /* 1: use MSR_PLATFORM_INFO, 0: >>>>> MSR_IA32_PERF_STATUS */ >>>>> + u32 freqs[MAX_NUM_FREQS]; >>>>> +}; >>>>> + >>>>> +static struct freq_desc freq_desc_tables[] = { >>>>> + /* PNW */ >>>>> + { 6, 0x27, 0, { 0, 0, 0, 0, 0, FREQ_100, 0, FREQ_83 } }, >>>>> + /* 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 >>>>> } }, >>>>> +}; >>>>> + >>>>> +static int match_cpu(u8 family, u8 model) >>>>> +{ >>>>> + int i; >>>>> + >>>>> + for (i = 0; i < ARRAY_SIZE(freq_desc_tables); i++) { >>>>> + if ((family == freq_desc_tables[i].x86_family) && >>>>> + (model == freq_desc_tables[i].x86_model)) >>>>> + return i; >>>>> + } >>>>> + >>>>> + return -1; >>>>> +} >>>>> + >>>>> +/* Map CPU reference clock freq ID(0-7) to CPU reference clock freq(KHz) >>>>> */ >>>>> +#define id_to_freq(cpu_index, freq_id) \ >>>>> + (freq_desc_tables[cpu_index].freqs[freq_id]) >>>>> + >>>>> +/* >>>>> + * Do MSR calibration only for known/supported CPUs. >>>>> + * >>>>> + * Returns the calibration value or 0 if MSR calibration failed. >>>>> + */ >>>>> +static unsigned long try_msr_calibrate_tsc(void) >>>>> +{ >>>>> + u32 lo, hi, ratio, freq_id, freq; >>>>> + unsigned long res; >>>>> + int cpu_index; >>>>> + >>>>> + cpu_index = match_cpu(gd->arch.x86, gd->arch.x86_model); >>>>> + if (cpu_index < 0) >>>>> + return 0; >>>>> + >>>>> + if (freq_desc_tables[cpu_index].msr_plat) { >>>>> + rdmsr(MSR_PLATFORM_INFO, lo, hi); >>>>> + ratio = (lo >> 8) & 0x1f; >>>>> + } else { >>>>> + rdmsr(MSR_IA32_PERF_STATUS, lo, hi); >>>>> + ratio = (hi >> 8) & 0x1f; >>>>> + } >>>>> + debug("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); >>>>> + debug("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 / 1000; >>>>> + debug("TSC runs at %lu MHz\n", res); >>>>> + >>>>> + return res; >>>>> + >>>>> +fail: >>>>> + debug("Fast TSC calibration using MSR failed\n"); >>>>> + return 0; >>>>> +} >>>>> + >>>>> void timer_set_base(u64 base) >>>>> { >>>>> gd->arch.tsc_base = base; >>>>> @@ -34,17 +137,16 @@ u64 __attribute__((no_instrument_function)) >>>>> get_ticks(void) >>>>> return now_tick - gd->arch.tsc_base; >>>>> } >>>>> >>>>> -#define PLATFORM_INFO_MSR 0xce >>>>> - >>>>> /* Get the speed of the TSC timer in MHz */ >>>>> unsigned __attribute__((no_instrument_function)) long get_tbclk_mhz(void) >>>>> { >>>>> - u32 ratio; >>>>> - u64 platform_info = native_read_msr(PLATFORM_INFO_MSR); >>>>> + unsigned long fast_calibrate; >>>>> + >>>>> + fast_calibrate = try_msr_calibrate_tsc(); >>>>> + if (!fast_calibrate) >>>>> + panic("TSC frequency is ZERO"); >>>>> >>>>> - /* 100MHz times Max Non Turbo ratio */ >>>>> - ratio = (platform_info >> 8) & 0xff; >>>>> - return 100 * ratio; >>>> >>>> What happens for platforms that have this MSR? Do we ignore it now? >>>> For my current platform this code is needed. >>> >>> In Linux the MSR calibration is only available on several Atom >>> platforms. If that fails, it falls back to use fast PIT calibration. >>> However, I think you can add an entry in the freq_desc_tables[] for >>> your platform if you want to use MSR calibration. >> >> I can add exceptions, but I wonder why this fails on my platform? Is >> your method supposed to work on any platform? > > Which one fails? Do you mean the quick_pit_calibrate() fails? Is that > because your platform does not has the legacy 8254 integrated?
I'll have to have another look at this. We dropped some of the old timer stuff a while ago and it would be a shame to bring it back when newer platforms apparently don't need it. But I may be talking about a different timer. Regards, Simon _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot