drivers/platform/x86/intel/ifs/sysfs.c

Source file repositories/reference/linux-study-clean/drivers/platform/x86/intel/ifs/sysfs.c

File Facts

System
Linux kernel
Corpus path
drivers/platform/x86/intel/ifs/sysfs.c
Extension
.c
Size
3445 bytes
Lines
156
Domain
Driver Families
Bucket
drivers/platform
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0-only
/* Copyright(c) 2022 Intel Corporation. */

#include <linux/cpu.h>
#include <linux/delay.h>
#include <linux/fs.h>
#include <linux/semaphore.h>
#include <linux/slab.h>

#include "ifs.h"

/*
 * Protects against simultaneous tests on multiple cores, or
 * reloading can file while a test is in progress
 */
static DEFINE_SEMAPHORE(ifs_sem, 1);

/*
 * The sysfs interface to check additional details of last test
 * cat /sys/devices/system/platform/ifs/details
 */
static ssize_t details_show(struct device *dev,
			    struct device_attribute *attr,
			    char *buf)
{
	struct ifs_data *ifsd = ifs_get_data(dev);

	return sysfs_emit(buf, "%#llx\n", ifsd->scan_details);
}

static DEVICE_ATTR_RO(details);

static const char * const status_msg[] = {
	[SCAN_NOT_TESTED] = "untested",
	[SCAN_TEST_PASS] = "pass",
	[SCAN_TEST_FAIL] = "fail"
};

/*
 * The sysfs interface to check the test status:
 * To check the status of last test
 * cat /sys/devices/platform/ifs/status
 */
static ssize_t status_show(struct device *dev,
			   struct device_attribute *attr,
			   char *buf)
{
	struct ifs_data *ifsd = ifs_get_data(dev);

	return sysfs_emit(buf, "%s\n", status_msg[ifsd->status]);
}

static DEVICE_ATTR_RO(status);

/*
 * The sysfs interface for single core testing
 * To start test, for example, cpu5
 * echo 5 > /sys/devices/platform/ifs/run_test
 * To check the result:
 * cat /sys/devices/platform/ifs/result
 * The sibling core gets tested at the same time.
 */
static ssize_t run_test_store(struct device *dev,
			      struct device_attribute *attr,
			      const char *buf, size_t count)
{
	unsigned int cpu;
	int rc;

	rc = kstrtouint(buf, 0, &cpu);
	if (rc < 0 || cpu >= nr_cpu_ids)
		return -EINVAL;

	if (down_interruptible(&ifs_sem))
		return -EINTR;

	rc = do_core_test(cpu, dev);

	up(&ifs_sem);

	return rc ? rc : count;
}

static DEVICE_ATTR_WO(run_test);

static ssize_t current_batch_store(struct device *dev,
				   struct device_attribute *attr,
				   const char *buf, size_t count)
{
	struct ifs_data *ifsd = ifs_get_data(dev);

Annotation

Implementation Notes