diff options
Diffstat (limited to 'drivers/platform/x86/intel_turbo_max_3.c')
| -rw-r--r-- | drivers/platform/x86/intel_turbo_max_3.c | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/drivers/platform/x86/intel_turbo_max_3.c b/drivers/platform/x86/intel_turbo_max_3.c new file mode 100644 index 000000000000..4f60d8e32a0a --- /dev/null +++ b/drivers/platform/x86/intel_turbo_max_3.c @@ -0,0 +1,151 @@ +/* + * Intel Turbo Boost Max Technology 3.0 legacy (non HWP) enumeration driver + * Copyright (c) 2017, Intel Corporation. + * All rights reserved. + * + * Author: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/topology.h> +#include <linux/workqueue.h> +#include <linux/cpuhotplug.h> +#include <linux/cpufeature.h> +#include <asm/cpu_device_id.h> +#include <asm/intel-family.h> + +#define MSR_OC_MAILBOX 0x150 +#define MSR_OC_MAILBOX_CMD_OFFSET 32 +#define MSR_OC_MAILBOX_RSP_OFFSET 32 +#define MSR_OC_MAILBOX_BUSY_BIT 63 +#define OC_MAILBOX_FC_CONTROL_CMD 0x1C + +/* + * Typical latency to get mail box response is ~3us, It takes +3 us to + * process reading mailbox after issuing mailbox write on a Broadwell 3.4 GHz + * system. So for most of the time, the first mailbox read should have the + * response, but to avoid some boundary cases retry twice. + */ +#define OC_MAILBOX_RETRY_COUNT 2 + +static int get_oc_core_priority(unsigned int cpu) +{ + u64 value, cmd = OC_MAILBOX_FC_CONTROL_CMD; + int ret, i; + + /* Issue favored core read command */ + value = cmd << MSR_OC_MAILBOX_CMD_OFFSET; + /* Set the busy bit to indicate OS is trying to issue command */ + value |= BIT_ULL(MSR_OC_MAILBOX_BUSY_BIT); + ret = wrmsrl_safe(MSR_OC_MAILBOX, value); + if (ret) { + pr_debug("cpu %d OC mailbox write failed\n", cpu); + return ret; + } + + for (i = 0; i < OC_MAILBOX_RETRY_COUNT; ++i) { + ret = rdmsrl_safe(MSR_OC_MAILBOX, &value); + if (ret) { + pr_debug("cpu %d OC mailbox read failed\n", cpu); + break; + } + + if (value & BIT_ULL(MSR_OC_MAILBOX_BUSY_BIT)) { + pr_debug("cpu %d OC mailbox still processing\n", cpu); + ret = -EBUSY; + continue; + } + + if ((value >> MSR_OC_MAILBOX_RSP_OFFSET) & 0xff) { + pr_debug("cpu %d OC mailbox cmd failed\n", cpu); + ret = -ENXIO; + break; + } + + ret = value & 0xff; + pr_debug("cpu %d max_ratio %d\n", cpu, ret); + break; + } + + return ret; +} + +/* + * The work item is needed to avoid CPU hotplug locking issues. The function + * itmt_legacy_set_priority() is called from CPU online callback, so can't + * call sched_set_itmt_support() from there as this function will aquire + * hotplug locks in its path. + */ +static void itmt_legacy_work_fn(struct work_struct *work) +{ + sched_set_itmt_support(); +} + +static DECLARE_WORK(sched_itmt_work, itmt_legacy_work_fn); + +static int itmt_legacy_cpu_online(unsigned int cpu) +{ + static u32 max_highest_perf = 0, min_highest_perf = U32_MAX; + int priority; + + priority = get_oc_core_priority(cpu); + if (priority < 0) + return 0; + + sched_set_itmt_core_prio(priority, cpu); + + /* Enable ITMT feature when a core with different priority is found */ + if (max_highest_perf <= min_highest_perf) { + if (priority > max_highest_perf) + max_highest_perf = priority; + + if (priority < min_highest_perf) + min_highest_perf = priority; + + if (max_highest_perf > min_highest_perf) + schedule_work(&sched_itmt_work); + } + + return 0; +} + +#define ICPU(model) { X86_VENDOR_INTEL, 6, model, X86_FEATURE_ANY, } + +static const struct x86_cpu_id itmt_legacy_cpu_ids[] = { + ICPU(INTEL_FAM6_BROADWELL_X), + {} +}; + +static int __init itmt_legacy_init(void) +{ + const struct x86_cpu_id *id; + int ret; + + id = x86_match_cpu(itmt_legacy_cpu_ids); + if (!id) + return -ENODEV; + + if (boot_cpu_has(X86_FEATURE_HWP)) + return -ENODEV; + + ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, + "platform/x86/turbo_max_3:online", + itmt_legacy_cpu_online, NULL); + if (ret < 0) + return ret; + + return 0; +} +late_initcall(itmt_legacy_init) |