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linux-7.2.3/drivers/platform/x86/amd/hfi/Kconfig

@@ -0,0 +1,18 @@
+# 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
+	depends on SCHED_MC_PRIO
+	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.

linux-7.2.3/drivers/platform/x86/amd/hfi/Makefile

@@ -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

linux-7.2.3/drivers/platform/x86/amd/hfi/hfi.c

@@ -0,0 +1,548 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * AMD Hardware Feedback Interface Driver
+ *
+ * Copyright (C) 2025 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/debugfs.h>
+#include <linux/gfp.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mailbox_client.h>
+#include <linux/mutex.h>
+#include <linux/percpu-defs.h>
+#include <linux/platform_device.h>
+#include <linux/smp.h>
+#include <linux/topology.h>
+#include <linux/workqueue.h>
+
+#include <asm/cpu_device_id.h>
+
+#include <acpi/pcc.h>
+#include <acpi/cppc_acpi.h>
+
+#define AMD_HFI_DRIVER		"amd_hfi"
+#define AMD_HFI_MAILBOX_COUNT		1
+#define AMD_HETERO_RANKING_TABLE_MIN_VER	2
+#define AMD_HETERO_RANKING_TABLE_MAX_VER	3
+
+#define AMD_HETERO_CPUID_27	0x80000027
+
+static struct platform_device *device;
+
+/**
+ * struct amd_shmem_info - Shared memory table for AMD HFI
+ *
+ * @header:	The PCCT table header including signature, length flags and command.
+ * @version_number:		Version number of the table
+ * @n_logical_processors:	Number of logical processors
+ * @n_capabilities:		Number of ranking dimensions (performance, efficiency, etc)
+ * @table_update_context:	Command being sent over the subspace
+ * @n_bitmaps:			Number of 32-bit bitmaps to enumerate all the APIC IDs
+ *				This is based on the maximum APIC ID enumerated in the system
+ * @reserved:			24 bit spare
+ * @table_data:			Bit Map(s) of enabled logical processors
+ *				Followed by the ranking data for each logical processor
+ */
+struct amd_shmem_info {
+	struct acpi_pcct_ext_pcc_shared_memory header;
+	u32	version_number		:8,
+		n_logical_processors	:8,
+		n_capabilities		:8,
+		table_update_context	:8;
+	u32	n_bitmaps		:8,
+		reserved		:24;
+	u32	table_data[];
+};
+
+struct amd_hfi_data {
+	const char	*name;
+	struct device	*dev;
+
+	/* PCCT table related */
+	struct pcc_mbox_chan	*pcc_chan;
+	void __iomem		*pcc_comm_addr;
+	struct acpi_subtable_header	*pcct_entry;
+	struct amd_shmem_info	*shmem;
+
+	struct dentry *dbgfs_dir;
+};
+
+/**
+ * struct amd_hfi_classes - HFI class capabilities per CPU
+ * @perf:	Performance capability
+ * @eff:	Power efficiency capability
+ *
+ * Capabilities of a logical processor in the ranking table. These capabilities
+ * are unitless and specific to each HFI class.
+ */
+struct amd_hfi_classes {
+	u32	perf;
+	u32	eff;
+};
+
+/**
+ * struct amd_hfi_cpuinfo - HFI workload class info per CPU
+ * @cpu:		CPU index
+ * @apic_id:		APIC id of the current CPU
+ * @class_index:	workload class ID index
+ * @nr_class:		max number of workload class supported
+ * @ipcc_scores:	ipcc scores for each class
+ * @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;
+	u32		apic_id;
+	s16		class_index;
+	u8		nr_class;
+	int		*ipcc_scores;
+	struct amd_hfi_classes	*amd_hfi_classes;
+};
+
+static DEFINE_PER_CPU(struct amd_hfi_cpuinfo, amd_hfi_cpuinfo) = {.class_index = -1};
+
+static DEFINE_MUTEX(hfi_cpuinfo_lock);
+
+static void amd_hfi_sched_itmt_work(struct work_struct *work)
+{
+	sched_set_itmt_support();
+}
+static DECLARE_WORK(sched_amd_hfi_itmt_work, amd_hfi_sched_itmt_work);
+
+static int find_cpu_index_by_apicid(unsigned int target_apicid)
+{
+	int cpu_index;
+
+	for_each_possible_cpu(cpu_index) {
+		struct cpuinfo_x86 *info = &cpu_data(cpu_index);
+
+		if (info->topo.apicid == target_apicid) {
+			pr_debug("match APIC id %u for CPU index: %d\n",
+				 info->topo.apicid, cpu_index);
+			return cpu_index;
+		}
+	}
+
+	return -ENODEV;
+}
+
+static int amd_hfi_fill_metadata(struct amd_hfi_data *amd_hfi_data)
+{
+	struct acpi_pcct_ext_pcc_slave *pcct_ext =
+		(struct acpi_pcct_ext_pcc_slave *)amd_hfi_data->pcct_entry;
+	void __iomem *pcc_comm_addr;
+	u32 apic_start = 0;
+
+	pcc_comm_addr = acpi_os_ioremap(amd_hfi_data->pcc_chan->shmem_base_addr,
+					amd_hfi_data->pcc_chan->shmem_size);
+	if (!pcc_comm_addr) {
+		dev_err(amd_hfi_data->dev, "failed to ioremap PCC common region mem\n");
+		return -ENOMEM;
+	}
+
+	memcpy_fromio(amd_hfi_data->shmem, pcc_comm_addr, pcct_ext->length);
+	iounmap(pcc_comm_addr);
+
+	if (amd_hfi_data->shmem->header.signature != PCC_SIGNATURE) {
+		dev_err(amd_hfi_data->dev, "invalid signature in shared memory\n");
+		return -EINVAL;
+	}
+	if (amd_hfi_data->shmem->version_number < AMD_HETERO_RANKING_TABLE_MIN_VER ||
+	    amd_hfi_data->shmem->version_number > AMD_HETERO_RANKING_TABLE_MAX_VER) {
+		dev_err(amd_hfi_data->dev, "invalid version %d\n",
+			amd_hfi_data->shmem->version_number);
+		return -EINVAL;
+	}
+
+	for (unsigned int i = 0; i < amd_hfi_data->shmem->n_bitmaps; i++) {
+		u32 bitmap = amd_hfi_data->shmem->table_data[i];
+
+		for (unsigned int j = 0; j < BITS_PER_TYPE(u32); j++) {
+			u32 apic_id = i * BITS_PER_TYPE(u32) + j;
+			struct amd_hfi_cpuinfo *info;
+			int cpu_index, apic_index;
+
+			if (!(bitmap & BIT(j)))
+				continue;
+
+			cpu_index = find_cpu_index_by_apicid(apic_id);
+			if (cpu_index < 0) {
+				dev_warn(amd_hfi_data->dev, "APIC ID %u not found\n", apic_id);
+				continue;
+			}
+
+			info = per_cpu_ptr(&amd_hfi_cpuinfo, cpu_index);
+			info->apic_id = apic_id;
+
+			/* Fill the ranking data for each logical processor */
+			info = per_cpu_ptr(&amd_hfi_cpuinfo, cpu_index);
+			apic_index = apic_start * info->nr_class * 2;
+			for (unsigned int k = 0; k < info->nr_class; k++) {
+				u32 *table = amd_hfi_data->shmem->table_data +
+					     amd_hfi_data->shmem->n_bitmaps +
+					     i * info->nr_class;
+
+				info->amd_hfi_classes[k].eff = table[apic_index + 2 * k];
+				info->amd_hfi_classes[k].perf = table[apic_index + 2 * k + 1];
+			}
+			apic_start++;
+		}
+	}
+
+	return 0;
+}
+
+static int amd_hfi_alloc_class_data(struct platform_device *pdev)
+{
+	struct amd_hfi_cpuinfo *hfi_cpuinfo;
+	struct device *dev = &pdev->dev;
+	u32 nr_class_id;
+	int idx;
+
+	nr_class_id = cpuid_eax(AMD_HETERO_CPUID_27);
+	if (nr_class_id > 255) {
+		dev_err(dev, "number of supported classes too large: %d\n",
+			nr_class_id);
+		return -EINVAL;
+	}
+
+	for_each_possible_cpu(idx) {
+		struct amd_hfi_classes *classes;
+		int *ipcc_scores;
+
+		classes = devm_kcalloc(dev,
+				       nr_class_id,
+				       sizeof(struct amd_hfi_classes),
+				       GFP_KERNEL);
+		if (!classes)
+			return -ENOMEM;
+		ipcc_scores = devm_kcalloc(dev, nr_class_id, sizeof(int), GFP_KERNEL);
+		if (!ipcc_scores)
+			return -ENOMEM;
+		hfi_cpuinfo = per_cpu_ptr(&amd_hfi_cpuinfo, idx);
+		hfi_cpuinfo->amd_hfi_classes = classes;
+		hfi_cpuinfo->ipcc_scores = ipcc_scores;
+		hfi_cpuinfo->nr_class = nr_class_id;
+	}
+
+	return 0;
+}
+
+static void amd_hfi_remove(struct platform_device *pdev)
+{
+	struct amd_hfi_data *dev = platform_get_drvdata(pdev);
+
+	debugfs_remove_recursive(dev->dbgfs_dir);
+}
+
+static int amd_set_hfi_ipcc_score(struct amd_hfi_cpuinfo *hfi_cpuinfo, int cpu)
+{
+	for (int i = 0; i < hfi_cpuinfo->nr_class; i++)
+		WRITE_ONCE(hfi_cpuinfo->ipcc_scores[i],
+			   hfi_cpuinfo->amd_hfi_classes[i].perf);
+
+	sched_set_itmt_core_prio(hfi_cpuinfo->ipcc_scores[0], cpu);
+
+	return 0;
+}
+
+static int amd_hfi_set_state(unsigned int cpu, bool state)
+{
+	int ret;
+
+	ret = wrmsrq_on_cpu(cpu, MSR_AMD_WORKLOAD_CLASS_CONFIG, state ? 1 : 0);
+	if (ret)
+		return ret;
+
+	return wrmsrq_on_cpu(cpu, MSR_AMD_WORKLOAD_HRST, 0x1);
+}
+
+/**
+ * amd_hfi_online() - Enable workload classification on @cpu
+ * @cpu: CPU in which the workload classification will be enabled
+ *
+ * Return: 0 on success, negative error code on failure.
+ */
+static int amd_hfi_online(unsigned int cpu)
+{
+	struct amd_hfi_cpuinfo *hfi_info = per_cpu_ptr(&amd_hfi_cpuinfo, cpu);
+	struct amd_hfi_classes *hfi_classes;
+	int ret;
+
+	if (WARN_ON_ONCE(!hfi_info))
+		return -EINVAL;
+
+	/*
+	 * Check if @cpu as an associated, initialized and ranking data must
+	 * be filled.
+	 */
+	hfi_classes = hfi_info->amd_hfi_classes;
+	if (!hfi_classes)
+		return -EINVAL;
+
+	guard(mutex)(&hfi_cpuinfo_lock);
+
+	ret = amd_hfi_set_state(cpu, true);
+	if (ret)
+		pr_err("WCT enable failed for CPU %u\n", cpu);
+
+	return ret;
+}
+
+/**
+ * amd_hfi_offline() - Disable workload classification on @cpu
+ * @cpu: CPU in which the workload classification will be disabled
+ *
+ * Remove @cpu from those covered by its HFI instance.
+ *
+ * Return: 0 on success, negative error code on failure
+ */
+static int amd_hfi_offline(unsigned int cpu)
+{
+	struct amd_hfi_cpuinfo *hfi_info = &per_cpu(amd_hfi_cpuinfo, cpu);
+	int ret;
+
+	if (WARN_ON_ONCE(!hfi_info))
+		return -EINVAL;
+
+	guard(mutex)(&hfi_cpuinfo_lock);
+
+	ret = amd_hfi_set_state(cpu, false);
+	if (ret)
+		pr_err("WCT disable failed for CPU %u\n", cpu);
+
+	return ret;
+}
+
+static int update_hfi_ipcc_scores(void)
+{
+	int cpu;
+	int ret;
+
+	for_each_possible_cpu(cpu) {
+		struct amd_hfi_cpuinfo *hfi_cpuinfo = per_cpu_ptr(&amd_hfi_cpuinfo, cpu);
+
+		ret = amd_set_hfi_ipcc_score(hfi_cpuinfo, cpu);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int amd_hfi_metadata_parser(struct platform_device *pdev,
+				   struct amd_hfi_data *amd_hfi_data)
+{
+	struct acpi_pcct_ext_pcc_slave *pcct_ext;
+	struct acpi_subtable_header *pcct_entry;
+	struct mbox_chan *pcc_mbox_channels;
+	struct acpi_table_header *pcct_tbl;
+	struct pcc_mbox_chan *pcc_chan;
+	acpi_status status;
+	int ret;
+
+	pcc_mbox_channels = devm_kcalloc(&pdev->dev, AMD_HFI_MAILBOX_COUNT,
+					 sizeof(*pcc_mbox_channels), GFP_KERNEL);
+	if (!pcc_mbox_channels)
+		return -ENOMEM;
+
+	pcc_chan = devm_kcalloc(&pdev->dev, AMD_HFI_MAILBOX_COUNT,
+				sizeof(*pcc_chan), GFP_KERNEL);
+	if (!pcc_chan)
+		return -ENOMEM;
+
+	status = acpi_get_table(ACPI_SIG_PCCT, 0, &pcct_tbl);
+	if (ACPI_FAILURE(status) || !pcct_tbl)
+		return -ENODEV;
+
+	/* get pointer to the first PCC subspace entry */
+	pcct_entry = (struct acpi_subtable_header *) (
+			(unsigned long)pcct_tbl + sizeof(struct acpi_table_pcct));
+
+	pcc_chan->mchan = &pcc_mbox_channels[0];
+
+	amd_hfi_data->pcc_chan = pcc_chan;
+	amd_hfi_data->pcct_entry = pcct_entry;
+	pcct_ext = (struct acpi_pcct_ext_pcc_slave *)pcct_entry;
+
+	if (pcct_ext->length <= 0) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	amd_hfi_data->shmem = devm_kzalloc(amd_hfi_data->dev, pcct_ext->length, GFP_KERNEL);
+	if (!amd_hfi_data->shmem) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	pcc_chan->shmem_base_addr = pcct_ext->base_address;
+	pcc_chan->shmem_size = pcct_ext->length;
+
+	/* parse the shared memory info from the PCCT table */
+	ret = amd_hfi_fill_metadata(amd_hfi_data);
+
+out:
+	/* Don't leak any ACPI memory */
+	acpi_put_table(pcct_tbl);
+
+	return ret;
+}
+
+static int class_capabilities_show(struct seq_file *s, void *unused)
+{
+	u32 cpu, idx;
+
+	seq_puts(s, "CPU #\tWLC\tPerf\tEff\n");
+	for_each_possible_cpu(cpu) {
+		struct amd_hfi_cpuinfo *hfi_cpuinfo = per_cpu_ptr(&amd_hfi_cpuinfo, cpu);
+
+		seq_printf(s, "%d", cpu);
+		for (idx = 0; idx < hfi_cpuinfo->nr_class; idx++) {
+			seq_printf(s, "\t%u\t%u\t%u\n", idx,
+				   hfi_cpuinfo->amd_hfi_classes[idx].perf,
+				   hfi_cpuinfo->amd_hfi_classes[idx].eff);
+		}
+	}
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(class_capabilities);
+
+static int amd_hfi_pm_resume(struct device *dev)
+{
+	int ret, cpu;
+
+	for_each_online_cpu(cpu) {
+		ret = amd_hfi_set_state(cpu, true);
+		if (ret < 0) {
+			dev_err(dev, "failed to enable workload class config: %d\n", ret);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static int amd_hfi_pm_suspend(struct device *dev)
+{
+	int ret, cpu;
+
+	for_each_online_cpu(cpu) {
+		ret = amd_hfi_set_state(cpu, false);
+		if (ret < 0) {
+			dev_err(dev, "failed to disable workload class config: %d\n", ret);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(amd_hfi_pm_ops, amd_hfi_pm_suspend, amd_hfi_pm_resume);
+
+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;
+	platform_set_drvdata(pdev, amd_hfi_data);
+
+	ret = amd_hfi_alloc_class_data(pdev);
+	if (ret)
+		return ret;
+
+	ret = amd_hfi_metadata_parser(pdev, amd_hfi_data);
+	if (ret)
+		return ret;
+
+	ret = update_hfi_ipcc_scores();
+	if (ret)
+		return ret;
+
+	/*
+	 * Tasks will already be running at the time this happens. This is
+	 * OK because rankings will be adjusted by the callbacks.
+	 */
+	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/amd_hfi:online",
+				amd_hfi_online, amd_hfi_offline);
+	if (ret < 0)
+		return ret;
+
+	schedule_work(&sched_amd_hfi_itmt_work);
+
+	amd_hfi_data->dbgfs_dir = debugfs_create_dir("amd_hfi", arch_debugfs_dir);
+	debugfs_create_file("class_capabilities", 0644, amd_hfi_data->dbgfs_dir, pdev,
+			    &class_capabilities_fops);
+
+	return 0;
+}
+
+static struct platform_driver amd_hfi_driver = {
+	.driver = {
+		.name = AMD_HFI_DRIVER,
+		.pm = &amd_hfi_pm_ops,
+		.acpi_match_table = ACPI_PTR(amd_hfi_platform_match),
+	},
+	.probe = amd_hfi_probe,
+	.remove = amd_hfi_remove,
+};
+
+static int __init amd_hfi_init(void)
+{
+	int ret;
+
+	if (acpi_disabled ||
+	    !cpu_feature_enabled(X86_FEATURE_AMD_HTR_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_driver_unregister(&amd_hfi_driver);
+	platform_device_unregister(device);
+}
+module_init(amd_hfi_init);
+module_exit(amd_hfi_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("AMD Hardware Feedback Interface Driver");