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![Paul Gortmaker](/assets/img/avatar_default.png)
The Kconfig currently controlling compilation of this code is: drivers/platform/x86/Kconfig:config INTEL_TURBO_MAX_3 drivers/platform/x86/Kconfig: bool "Intel Turbo Boost Max Technology 3.0 enumeration driver" ...meaning that it currently is not being built as a module by anyone. Lets remove the couple traces of modular infrastructure use, so that when reading the driver there is no doubt it is builtin-only. Also note that MODULE_DEVICE_TABLE is a no-op for non-modular code. We also delete the MODULE_LICENSE tag etc. since all that information was (or is now) contained at the top of the file in the comments. We do uncover some implicit includes during build coverage that were hidden behind the module.h which pulls in a lot of dependants. Cc: Andy Shevchenko <andy@infradead.org> Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Cc: platform-driver-x86@vger.kernel.org Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Darren Hart <dvhart@linux.intel.com>
151 lines
3.9 KiB
C
151 lines
3.9 KiB
C
/*
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* Intel Turbo Boost Max Technology 3.0 legacy (non HWP) enumeration driver
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* Copyright (c) 2017, Intel Corporation.
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* All rights reserved.
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*
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* Author: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/topology.h>
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#include <linux/workqueue.h>
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#include <linux/cpuhotplug.h>
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#include <linux/cpufeature.h>
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#include <asm/cpu_device_id.h>
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#include <asm/intel-family.h>
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#define MSR_OC_MAILBOX 0x150
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#define MSR_OC_MAILBOX_CMD_OFFSET 32
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#define MSR_OC_MAILBOX_RSP_OFFSET 32
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#define MSR_OC_MAILBOX_BUSY_BIT 63
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#define OC_MAILBOX_FC_CONTROL_CMD 0x1C
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/*
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* Typical latency to get mail box response is ~3us, It takes +3 us to
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* process reading mailbox after issuing mailbox write on a Broadwell 3.4 GHz
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* system. So for most of the time, the first mailbox read should have the
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* response, but to avoid some boundary cases retry twice.
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*/
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#define OC_MAILBOX_RETRY_COUNT 2
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static int get_oc_core_priority(unsigned int cpu)
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{
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u64 value, cmd = OC_MAILBOX_FC_CONTROL_CMD;
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int ret, i;
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/* Issue favored core read command */
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value = cmd << MSR_OC_MAILBOX_CMD_OFFSET;
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/* Set the busy bit to indicate OS is trying to issue command */
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value |= BIT_ULL(MSR_OC_MAILBOX_BUSY_BIT);
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ret = wrmsrl_safe(MSR_OC_MAILBOX, value);
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if (ret) {
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pr_debug("cpu %d OC mailbox write failed\n", cpu);
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return ret;
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}
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for (i = 0; i < OC_MAILBOX_RETRY_COUNT; ++i) {
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ret = rdmsrl_safe(MSR_OC_MAILBOX, &value);
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if (ret) {
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pr_debug("cpu %d OC mailbox read failed\n", cpu);
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break;
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}
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if (value & BIT_ULL(MSR_OC_MAILBOX_BUSY_BIT)) {
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pr_debug("cpu %d OC mailbox still processing\n", cpu);
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ret = -EBUSY;
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continue;
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}
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if ((value >> MSR_OC_MAILBOX_RSP_OFFSET) & 0xff) {
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pr_debug("cpu %d OC mailbox cmd failed\n", cpu);
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ret = -ENXIO;
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break;
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}
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ret = value & 0xff;
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pr_debug("cpu %d max_ratio %d\n", cpu, ret);
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break;
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}
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return ret;
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}
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/*
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* The work item is needed to avoid CPU hotplug locking issues. The function
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* itmt_legacy_set_priority() is called from CPU online callback, so can't
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* call sched_set_itmt_support() from there as this function will aquire
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* hotplug locks in its path.
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*/
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static void itmt_legacy_work_fn(struct work_struct *work)
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{
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sched_set_itmt_support();
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}
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static DECLARE_WORK(sched_itmt_work, itmt_legacy_work_fn);
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static int itmt_legacy_cpu_online(unsigned int cpu)
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{
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static u32 max_highest_perf = 0, min_highest_perf = U32_MAX;
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int priority;
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priority = get_oc_core_priority(cpu);
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if (priority < 0)
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return 0;
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sched_set_itmt_core_prio(priority, cpu);
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/* Enable ITMT feature when a core with different priority is found */
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if (max_highest_perf <= min_highest_perf) {
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if (priority > max_highest_perf)
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max_highest_perf = priority;
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if (priority < min_highest_perf)
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min_highest_perf = priority;
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if (max_highest_perf > min_highest_perf)
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schedule_work(&sched_itmt_work);
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}
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return 0;
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}
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#define ICPU(model) { X86_VENDOR_INTEL, 6, model, X86_FEATURE_ANY, }
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static const struct x86_cpu_id itmt_legacy_cpu_ids[] = {
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ICPU(INTEL_FAM6_BROADWELL_X),
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{}
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};
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static int __init itmt_legacy_init(void)
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{
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const struct x86_cpu_id *id;
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int ret;
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id = x86_match_cpu(itmt_legacy_cpu_ids);
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if (!id)
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return -ENODEV;
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if (boot_cpu_has(X86_FEATURE_HWP))
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return -ENODEV;
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ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN,
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"platform/x86/turbo_max_3:online",
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itmt_legacy_cpu_online, NULL);
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if (ret < 0)
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return ret;
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return 0;
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}
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late_initcall(itmt_legacy_init)
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