path: root/drivers/hwmon/dell-smm-hwmon.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * dell-smm-hwmon.c -- Linux driver for accessing the SMM BIOS on Dell laptops.
 *
 * Copyright (C) 2001  Massimo Dal Zotto <dz@debian.org>
 *
 * Hwmon integration:
 * Copyright (C) 2011  Jean Delvare <jdelvare@suse.de>
 * Copyright (C) 2013, 2014  Guenter Roeck <linux@roeck-us.net>
 * Copyright (C) 2014, 2015  Pali Rohár <pali.rohar@gmail.com>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/cpu.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/dmi.h>
#include <linux/capability.h>
#include <linux/mutex.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/sched.h>
#include <linux/ctype.h>
#include <linux/smp.h>

#include <linux/i8k.h>

#define I8K_SMM_FN_STATUS	0x0025
#define I8K_SMM_POWER_STATUS	0x0069
#define I8K_SMM_SET_FAN		0x01a3
#define I8K_SMM_GET_FAN		0x00a3
#define I8K_SMM_GET_SPEED	0x02a3
#define I8K_SMM_GET_FAN_TYPE	0x03a3
#define I8K_SMM_GET_NOM_SPEED	0x04a3
#define I8K_SMM_GET_TEMP	0x10a3
#define I8K_SMM_GET_TEMP_TYPE	0x11a3
#define I8K_SMM_GET_DELL_SIG1	0xfea3
#define I8K_SMM_GET_DELL_SIG2	0xffa3

#define I8K_FAN_MULT		30
#define I8K_FAN_MAX_RPM		30000
#define I8K_MAX_TEMP		127

#define I8K_FN_NONE		0x00
#define I8K_FN_UP		0x01
#define I8K_FN_DOWN		0x02
#define I8K_FN_MUTE		0x04
#define I8K_FN_MASK		0x07
#define I8K_FN_SHIFT		8

#define I8K_POWER_AC		0x05
#define I8K_POWER_BATTERY	0x01

static DEFINE_MUTEX(i8k_mutex);
static char bios_version[4];
static char bios_machineid[16];
static struct device *i8k_hwmon_dev;
static u32 i8k_hwmon_flags;
static uint i8k_fan_mult = I8K_FAN_MULT;
static uint i8k_pwm_mult;
static uint i8k_fan_max = I8K_FAN_HIGH;
static bool disallow_fan_type_call;
static bool disallow_fan_support;

#define I8K_HWMON_HAVE_TEMP1	(1 << 0)
#define I8K_HWMON_HAVE_TEMP2	(1 << 1)
#define I8K_HWMON_HAVE_TEMP3	(1 << 2)
#define I8K_HWMON_HAVE_TEMP4	(1 << 3)
#define I8K_HWMON_HAVE_TEMP5	(1 << 4)
#define I8K_HWMON_HAVE_TEMP6	(1 << 5)
#define I8K_HWMON_HAVE_TEMP7	(1 << 6)
#define I8K_HWMON_HAVE_TEMP8	(1 << 7)
#define I8K_HWMON_HAVE_TEMP9	(1 << 8)
#define I8K_HWMON_HAVE_TEMP10	(1 << 9)
#define I8K_HWMON_HAVE_FAN1	(1 << 10)
#define I8K_HWMON_HAVE_FAN2	(1 << 11)
#define I8K_HWMON_HAVE_FAN3	(1 << 12)

MODULE_AUTHOR("Massimo Dal Zotto (dz@debian.org)");
MODULE_AUTHOR("Pali Rohár <pali.rohar@gmail.com>");
MODULE_DESCRIPTION("Dell laptop SMM BIOS hwmon driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("i8k");

static bool force;
module_param(force, bool, 0);
MODULE_PARM_DESC(force, "Force loading without checking for supported models");

static bool ignore_dmi;
module_param(ignore_dmi, bool, 0);
MODULE_PARM_DESC(ignore_dmi, "Continue probing hardware even if DMI data does not match");

#if IS_ENABLED(CONFIG_I8K)
static bool restricted = true;
module_param(restricted, bool, 0);
MODULE_PARM_DESC(restricted, "Restrict fan control and serial number to CAP_SYS_ADMIN (default: 1)");

static bool power_status;
module_param(power_status, bool, 0600);
MODULE_PARM_DESC(power_status, "Report power status in /proc/i8k (default: 0)");
#endif

static uint fan_mult;
module_param(fan_mult, uint, 0);
MODULE_PARM_DESC(fan_mult, "Factor to multiply fan speed with (default: autodetect)");

static uint fan_max;
module_param(fan_max, uint, 0);
MODULE_PARM_DESC(fan_max, "Maximum configurable fan speed (default: autodetect)");

struct smm_regs {
	unsigned int eax;
	unsigned int ebx __packed;
	unsigned int ecx __packed;
	unsigned int edx __packed;
	unsigned int esi __packed;
	unsigned int edi __packed;
};

static inline const char *i8k_get_dmi_data(int field)
{
	const char *dmi_data = dmi_get_system_info(field);

	return dmi_data && *dmi_data ? dmi_data : "?";
}

/*
 * Call the System Management Mode BIOS. Code provided by Jonathan Buzzard.
 */
static int i8k_smm_func(void *par)
{
	int rc;
	struct smm_regs *regs = par;
	int eax = regs->eax;

#ifdef DEBUG
	int ebx = regs->