On Thu, 10 Oct 2024, Mario Limonciello wrote: > From: Perry Yuan <Perry.Yuan@xxxxxxx> > > The AMD Heterogeneous core design and Hardware Feedback Interface (HFI) > provide behavioral classification and a dynamically updated ranking table > for the scheduler to use when choosing cores for tasks. > > There are two CPU core types defined: `Classic Core` and `Dense Core`. > "Classic" cores are the standard performance cores, while "Dense" cores > are optimized for area and efficiency. > > Heterogeneous compute refers to CPU implementations that are comprised > of more than one architectural class, each with two capabilities. This > means each CPU reports two separate capabilities: "perf" and "eff". > > Each capability lists all core ranking numbers between 0 and 255, where > a higher number represents a higher capability. > > Heterogeneous systems can also extend to more than two architectural > classes. > > The purpose of the scheduling feedback mechanism is to provide information > to the operating system scheduler in real time, allowing the scheduler to > direct threads to the optimal core during task scheduling. > > All core ranking data are provided by the BIOS via a shared memory ranking > table, which the driver reads and uses to update core capabilities to the > scheduler. When the hardware updates the table, it generates a platform > interrupt to notify the OS to read the new ranking table. > > Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537 > Signed-off-by: Perry Yuan <perry.yuan@xxxxxxx> > Co-developed-by: Mario Limonciello <mario.limonciello@xxxxxxx> > Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx> > --- > v2: > * Drop unnecessary select > * Make tristate instead of bool > * Drop error messages > * Drop unnecessary function declarations for init > * Fix cleanup for amd_hfi_exit() > * Drop unnecessary variables for upcoming features > --- > drivers/platform/x86/amd/Kconfig | 1 + > drivers/platform/x86/amd/Makefile | 1 + > drivers/platform/x86/amd/hfi/Kconfig | 20 +++ > drivers/platform/x86/amd/hfi/Makefile | 7 ++ > drivers/platform/x86/amd/hfi/hfi.c | 169 ++++++++++++++++++++++++++ > 5 files changed, 198 insertions(+) > create mode 100644 drivers/platform/x86/amd/hfi/Kconfig > create mode 100644 drivers/platform/x86/amd/hfi/Makefile > create mode 100644 drivers/platform/x86/amd/hfi/hfi.c > > diff --git a/drivers/platform/x86/amd/Kconfig b/drivers/platform/x86/amd/Kconfig > index f88682d36447..c3f69dbe3037 100644 > --- a/drivers/platform/x86/amd/Kconfig > +++ b/drivers/platform/x86/amd/Kconfig > @@ -5,6 +5,7 @@ > > source "drivers/platform/x86/amd/pmf/Kconfig" > source "drivers/platform/x86/amd/pmc/Kconfig" > +source "drivers/platform/x86/amd/hfi/Kconfig" > > config AMD_HSMP > tristate "AMD HSMP Driver" > diff --git a/drivers/platform/x86/amd/Makefile b/drivers/platform/x86/amd/Makefile > index dcec0a46f8af..2676fc81fee5 100644 > --- a/drivers/platform/x86/amd/Makefile > +++ b/drivers/platform/x86/amd/Makefile > @@ -9,3 +9,4 @@ amd_hsmp-y := hsmp.o > obj-$(CONFIG_AMD_HSMP) += amd_hsmp.o > obj-$(CONFIG_AMD_PMF) += pmf/ > obj-$(CONFIG_AMD_WBRF) += wbrf.o > +obj-$(CONFIG_AMD_HFI) += hfi/ > diff --git a/drivers/platform/x86/amd/hfi/Kconfig b/drivers/platform/x86/amd/hfi/Kconfig > new file mode 100644 > index 000000000000..08051cd4f74d > --- /dev/null > +++ b/drivers/platform/x86/amd/hfi/Kconfig > @@ -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. > + > + > diff --git a/drivers/platform/x86/amd/hfi/Makefile b/drivers/platform/x86/amd/hfi/Makefile > new file mode 100644 > index 000000000000..672c6ac106e9 > --- /dev/null > +++ b/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 > diff --git a/drivers/platform/x86/amd/hfi/hfi.c b/drivers/platform/x86/amd/hfi/hfi.c > new file mode 100644 > index 000000000000..da2e667107e8 > --- /dev/null > +++ b/drivers/platform/x86/amd/hfi/hfi.c > @@ -0,0 +1,169 @@ > +// SPDX-License-Identifier: GPL-2.0-or-later > +/* > + * AMD Hardware Feedback Interface Driver > + * > + * Copyright (C) 2024 Advanced Micro Devices, Inc. All Rights Reserved. > + * > + * Author: Perry Yuan <Perry.Yuan@xxxxxxx> > + * Extra line. > + */ > + > +#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/printk.h> > +#include <linux/smp.h> > +#include <linux/string.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; > +} __packed; Unnecessary packed. > + > +/** > + * 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_warn(dev, "failed to get supported class number from CPUID %d\n", > + AMD_HETERO_CPUID_27); > + return -EINVAL; > + } > + > + for_each_possible_cpu(idx) { > + hfi_cpuinfo = per_cpu_ptr(&amd_hfi_cpuinfo, idx); > + hfi_cpuinfo->amd_hfi_classes = devm_kmalloc(dev, nr_class_id * > + sizeof(struct amd_hfi_classes), GFP_KERNEL); I recommend splitting this line differently. Why it's not using kzalloc? > + if (!hfi_cpuinfo->amd_hfi_classes) > + return -ENOMEM; > + > + 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); > + > + mutex_destroy(&dev->lock); > +} > + > +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; > + > + mutex_init(&amd_hfi_data->lock); No idea why the empty line is put between these initializations of the data structure fields. > + platform_set_drvdata(pdev, amd_hfi_data); > + > + /* alloc data array for hardware feedback class data */ Unnecessary comment? Isn't the function name enough to tell it? > + ret = amd_hfi_alloc_class_data(pdev); > + if (ret) > + goto out; > + > +out: I'm guessing this might be to reduce churn in some patch after this, if not, this is enough: return amd_hfi_alloc_class_data(pdev); > + return ret; > +} > + > +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, > + .remove_new = amd_hfi_remove, > +}; > + > +static int __init amd_hfi_init(void) > +{ > + int ret; > + > + if (acpi_disabled || > + !boot_cpu_has(X86_FEATURE_HETERO_CORE_TOPOLOGY) || > + !boot_cpu_has(X86_FEATURE_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"); I assume HFI is the correct capitalization given I see some comments with that. Please correct any user visible print outs to use the capitalized form. > + 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"); > -- i.
