@@ -6,6 +6,7 @@
source "drivers/platform/x86/amd/hsmp/Kconfig"
source "drivers/platform/x86/amd/pmf/Kconfig"
source "drivers/platform/x86/amd/pmc/Kconfig"
+source "drivers/platform/x86/amd/hfi/Kconfig"
config AMD_3D_VCACHE
tristate "AMD 3D V-Cache Performance Optimizer Driver"
@@ -10,3 +10,4 @@ obj-$(CONFIG_AMD_PMC) += pmc/
obj-$(CONFIG_AMD_HSMP) += hsmp/
obj-$(CONFIG_AMD_PMF) += pmf/
obj-$(CONFIG_AMD_WBRF) += wbrf.o
+obj-$(CONFIG_AMD_HFI) += hfi/
new file mode 100644
@@ -0,0 +1,20 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# AMD Hardware Feedback Interface Driver
+#
+
+config AMD_HFI
+ bool "AMD Hetero Core Hardware Feedback Driver"
+ depends on ACPI
+ depends on CPU_SUP_AMD
+ help
+ Select this option to enable the AMD Heterogeneous Core Hardware
+ Feedback Interface. If selected, hardware provides runtime thread
+ classification guidance to the operating system on the performance and
+ energy efficiency capabilities of each heterogeneous CPU core. These
+ capabilities may vary due to the inherent differences in the core types
+ and can also change as a result of variations in the operating
+ conditions of the system such as power and thermal limits. If selected,
+ the kernel relays updates in heterogeneous CPUs' capabilities to
+ userspace, allowing for more optimal task scheduling and resource
+ allocation, leveraging the diverse set of cores available.
new file mode 100644
@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# AMD Hardware Feedback Interface Driver
+#
+
+obj-$(CONFIG_AMD_HFI) += amd_hfi.o
+amd_hfi-objs := hfi.o
new file mode 100644
@@ -0,0 +1,161 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * AMD Hardware Feedback Interface Driver
+ *
+ * Copyright (C) 2024 Advanced Micro Devices, Inc. All Rights Reserved.
+ *
+ * Authors: Perry Yuan <Perry.Yuan@amd.com>
+ * Mario Limonciello <mario.limonciello@amd.com>
+ */
+
+#define pr_fmt(fmt) "amd-hfi: " fmt
+
+#include <linux/acpi.h>
+#include <linux/cpu.h>
+#include <linux/cpumask.h>
+#include <linux/gfp.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
+#include <linux/smp.h>
+
+#define AMD_HFI_DRIVER "amd_hfi"
+#define AMD_HETERO_CPUID_27 0x80000027
+static struct platform_device *device;
+
+struct amd_hfi_data {
+ const char *name;
+ struct device *dev;
+ struct mutex lock;
+};
+
+struct amd_hfi_classes {
+ u32 perf;
+ u32 eff;
+};
+
+/**
+ * struct amd_hfi_cpuinfo - HFI workload class info per CPU
+ * @cpu: cpu index
+ * @cpus: mask of cpus associated with amd_hfi_cpuinfo
+ * @class_index: workload class ID index
+ * @nr_class: max number of workload class supported
+ * @amd_hfi_classes: current cpu workload class ranking data
+ *
+ * Parameters of a logical processor linked with hardware feedback class
+ */
+struct amd_hfi_cpuinfo {
+ int cpu;
+ cpumask_var_t cpus;
+ s16 class_index;
+ u8 nr_class;
+ struct amd_hfi_classes *amd_hfi_classes;
+};
+
+static DEFINE_PER_CPU(struct amd_hfi_cpuinfo, amd_hfi_cpuinfo) = {.class_index = -1};
+
+static int amd_hfi_alloc_class_data(struct platform_device *pdev)
+{
+ struct amd_hfi_cpuinfo *hfi_cpuinfo;
+ struct device *dev = &pdev->dev;
+ int idx;
+ int nr_class_id;
+
+ nr_class_id = cpuid_eax(AMD_HETERO_CPUID_27);
+ if (nr_class_id < 0 || nr_class_id > 255) {
+ dev_err(dev, "failed to get number of supported classes: %d\n",
+ nr_class_id);
+ return -EINVAL;
+ }
+
+ for_each_present_cpu(idx) {
+ struct amd_hfi_classes *classes;
+
+ classes = devm_kzalloc(dev,
+ nr_class_id * sizeof(struct amd_hfi_classes),
+ GFP_KERNEL);
+ if (!classes)
+ return -ENOMEM;
+ hfi_cpuinfo = per_cpu_ptr(&amd_hfi_cpuinfo, idx);
+ hfi_cpuinfo->amd_hfi_classes = classes;
+ hfi_cpuinfo->nr_class = nr_class_id;
+ }
+
+ return 0;
+}
+
+static const struct acpi_device_id amd_hfi_platform_match[] = {
+ {"AMDI0104", 0},
+ { }
+};
+MODULE_DEVICE_TABLE(acpi, amd_hfi_platform_match);
+
+static int amd_hfi_probe(struct platform_device *pdev)
+{
+ struct amd_hfi_data *amd_hfi_data;
+ int ret;
+
+ if (!acpi_match_device(amd_hfi_platform_match, &pdev->dev))
+ return -ENODEV;
+
+ amd_hfi_data = devm_kzalloc(&pdev->dev, sizeof(*amd_hfi_data), GFP_KERNEL);
+ if (!amd_hfi_data)
+ return -ENOMEM;
+
+ amd_hfi_data->dev = &pdev->dev;
+ ret = devm_mutex_init(&pdev->dev, &amd_hfi_data->lock);
+ if (ret)
+ return ret;
+ platform_set_drvdata(pdev, amd_hfi_data);
+
+ ret = amd_hfi_alloc_class_data(pdev);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+static struct platform_driver amd_hfi_driver = {
+ .driver = {
+ .name = AMD_HFI_DRIVER,
+ .owner = THIS_MODULE,
+ .acpi_match_table = ACPI_PTR(amd_hfi_platform_match),
+ },
+ .probe = amd_hfi_probe,
+};
+
+static int __init amd_hfi_init(void)
+{
+ int ret;
+
+ if (acpi_disabled ||
+ !cpu_feature_enabled(X86_FEATURE_AMD_HETEROGENEOUS_CORES) ||
+ !cpu_feature_enabled(X86_FEATURE_AMD_WORKLOAD_CLASS))
+ return -ENODEV;
+
+ device = platform_device_register_simple(AMD_HFI_DRIVER, -1, NULL, 0);
+ if (IS_ERR(device)) {
+ pr_err("unable to register HFI platform device\n");
+ return PTR_ERR(device);
+ }
+
+ ret = platform_driver_register(&amd_hfi_driver);
+ if (ret)
+ pr_err("failed to register HFI driver\n");
+
+ return ret;
+}
+
+static __exit void amd_hfi_exit(void)
+{
+ platform_device_unregister(device);
+ platform_driver_unregister(&amd_hfi_driver);
+}
+module_init(amd_hfi_init);
+module_exit(amd_hfi_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("AMD Hardware Feedback Interface Driver");