Quelle  pltdrv.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0

/*
 * Intel PMC Core platform init
 * Copyright (c) 2019, Google Inc.
 * Author - Rajat Jain
 *
 * This code instantiates platform devices for intel_pmc_core driver, only
 * on supported platforms that may not have the ACPI devices in the ACPI tables.
 * No new platforms should be added here, because we expect that new platforms
 * should all have the ACPI device, which is the preferred way of enumeration.
 */

#include <linux/acpi.h>
#include <linux/module.h>
#include <linux/platform_device.h>

#include <asm/cpu_device_id.h>
#include <asm/intel-family.h>

#include <xen/xen.h>

static void intel_pmc_core_release(struct device *dev)
{
 kfree(dev);
}

static struct platform_device *pmc_core_device;

/*
 * intel_pmc_core_platform_ids is the list of platforms where we want to
 * instantiate the platform_device if not already instantiated. This is
 * different than intel_pmc_core_ids in intel_pmc_core.c which is the
 * list of platforms that the driver supports for pmc_core device. The
 * other list may grow, but this list should not.
 */
static const struct x86_cpu_id intel_pmc_core_platform_ids[] = {
 X86_MATCH_VFM(INTEL_SKYLAKE_L,  &pmc_core_device),
 X86_MATCH_VFM(INTEL_SKYLAKE,  &pmc_core_device),
 X86_MATCH_VFM(INTEL_KABYLAKE_L,  &pmc_core_device),
 X86_MATCH_VFM(INTEL_KABYLAKE,  &pmc_core_device),
 X86_MATCH_VFM(INTEL_CANNONLAKE_L, &pmc_core_device),
 X86_MATCH_VFM(INTEL_ICELAKE_L,  &pmc_core_device),
 X86_MATCH_VFM(INTEL_COMETLAKE,  &pmc_core_device),
 X86_MATCH_VFM(INTEL_COMETLAKE_L, &pmc_core_device),
 {}
};
MODULE_DEVICE_TABLE(x86cpu, intel_pmc_core_platform_ids);

static int __init pmc_core_platform_init(void)
{
 int retval;

 /* Skip creating the platform device if ACPI already has a device */
 if (acpi_dev_present("INT33A1", NULL, -1))
  return -ENODEV;

 /*
 * Skip forcefully attaching the device for VMs. Make an exception for
 * Xen dom0, which does have full hardware access.
 */
 if (cpu_feature_enabled(X86_FEATURE_HYPERVISOR) && !xen_initial_domain())
  return -ENODEV;

 if (!x86_match_cpu(intel_pmc_core_platform_ids))
  return -ENODEV;

 pmc_core_device = kzalloc(sizeof(*pmc_core_device), GFP_KERNEL);
 if (!pmc_core_device)
  return -ENOMEM;

 pmc_core_device->name = "intel_pmc_core";
 pmc_core_device->dev.release = intel_pmc_core_release;

 retval = platform_device_register(pmc_core_device);
 if (retval)
  platform_device_put(pmc_core_device);

 return retval;
}

static void __exit pmc_core_platform_exit(void)
{
 platform_device_unregister(pmc_core_device);
}

module_init(pmc_core_platform_init);
module_exit(pmc_core_platform_exit);
MODULE_DESCRIPTION("Intel PMC Core platform driver");
MODULE_LICENSE("GPL v2");