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Diffstat (limited to 'drivers/thermal/intel/intel_hfi.c')
| -rw-r--r-- | drivers/thermal/intel/intel_hfi.c | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/drivers/thermal/intel/intel_hfi.c b/drivers/thermal/intel/intel_hfi.c new file mode 100644 index 000000000000..969f4a150973 --- /dev/null +++ b/drivers/thermal/intel/intel_hfi.c @@ -0,0 +1,181 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Hardware Feedback Interface Driver + * + * Copyright (c) 2021, Intel Corporation. + * + * Authors: Aubrey Li <aubrey.li@linux.intel.com> + * Ricardo Neri <ricardo.neri-calderon@linux.intel.com> + * + * + * The Hardware Feedback Interface provides a performance and energy efficiency + * capability information for each CPU in the system. Depending on the processor + * model, hardware may periodically update these capabilities as a result of + * changes in the operating conditions (e.g., power limits or thermal + * constraints). On other processor models, there is a single HFI update + * at boot. + * + * This file provides functionality to process HFI updates and relay these + * updates to userspace. + */ + +#define pr_fmt(fmt) "intel-hfi: " fmt + +#include <linux/bitops.h> +#include <linux/cpufeature.h> +#include <linux/math.h> +#include <linux/printk.h> +#include <linux/processor.h> +#include <linux/slab.h> +#include <linux/topology.h> + +#include "intel_hfi.h" + +/* CPUID detection and enumeration definitions for HFI */ + +#define CPUID_HFI_LEAF 6 + +union hfi_capabilities { + struct { + u8 performance:1; + u8 energy_efficiency:1; + u8 __reserved:6; + } split; + u8 bits; +}; + +union cpuid6_edx { + struct { + union hfi_capabilities capabilities; + u32 table_pages:4; + u32 __reserved:4; + s32 index:16; + } split; + u32 full; +}; + +/** + * struct hfi_cpu_data - HFI capabilities per CPU + * @perf_cap: Performance capability + * @ee_cap: Energy efficiency capability + * + * Capabilities of a logical processor in the HFI table. These capabilities are + * unitless. + */ +struct hfi_cpu_data { + u8 perf_cap; + u8 ee_cap; +} __packed; + +/** + * struct hfi_hdr - Header of the HFI table + * @perf_updated: Hardware updated performance capabilities + * @ee_updated: Hardware updated energy efficiency capabilities + * + * Properties of the data in an HFI table. + */ +struct hfi_hdr { + u8 perf_updated; + u8 ee_updated; +} __packed; + +/** + * struct hfi_instance - Representation of an HFI instance (i.e., a table) + * @local_table: Base of the local copy of the HFI table + * @timestamp: Timestamp of the last update of the local table. + * Located at the base of the local table. + * @hdr: Base address of the header of the local table + * @data: Base address of the data of the local table + * + * A set of parameters to parse and navigate a specific HFI table. + */ +struct hfi_instance { + union { + void *local_table; + u64 *timestamp; + }; + void *hdr; + void *data; +}; + +/** + * struct hfi_features - Supported HFI features + * @nr_table_pages: Size of the HFI table in 4KB pages + * @cpu_stride: Stride size to locate the capability data of a logical + * processor within the table (i.e., row stride) + * @hdr_size: Size of the table header + * + * Parameters and supported features that are common to all HFI instances + */ +struct hfi_features { + unsigned int nr_table_pages; + unsigned int cpu_stride; + unsigned int hdr_size; +}; + +static int max_hfi_instances; +static struct hfi_instance *hfi_instances; + +static struct hfi_features hfi_features; + +static __init int hfi_parse_features(void) +{ + unsigned int nr_capabilities; + union cpuid6_edx edx; + + if (!boot_cpu_has(X86_FEATURE_HFI)) + return -ENODEV; + + /* + * If we are here we know that CPUID_HFI_LEAF exists. Parse the + * supported capabilities and the size of the HFI table. + */ + edx.full = cpuid_edx(CPUID_HFI_LEAF); + + if (!edx.split.capabilities.split.performance) { + pr_debug("Performance reporting not supported! Not using HFI\n"); + return -ENODEV; + } + + /* + * The number of supported capabilities determines the number of + * columns in the HFI table. Exclude the reserved bits. + */ + edx.split.capabilities.split.__reserved = 0; + nr_capabilities = hweight8(edx.split.capabilities.bits); + + /* The number of 4KB pages required by the table */ + hfi_features.nr_table_pages = edx.split.table_pages + 1; + + /* + * The header contains change indications for each supported feature. + * The size of the table header is rounded up to be a multiple of 8 + * bytes. + */ + hfi_features.hdr_size = DIV_ROUND_UP(nr_capabilities, 8) * 8; + + /* + * Data of each logical processor is also rounded up to be a multiple + * of 8 bytes. + */ + hfi_features.cpu_stride = DIV_ROUND_UP(nr_capabilities, 8) * 8; + + return 0; +} + +void __init intel_hfi_init(void) +{ + if (hfi_parse_features()) + return; + + /* There is one HFI instance per die/package. */ + max_hfi_instances = topology_max_packages() * + topology_max_die_per_package(); + + /* + * This allocation may fail. CPU hotplug callbacks must check + * for a null pointer. + */ + hfi_instances = kcalloc(max_hfi_instances, sizeof(*hfi_instances), + GFP_KERNEL); +} |