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a54fe61639
linux/drivers/hwmon/sch5627.c
Armin Wolf a54fe61639 hwmon: (sch5627) Use regmap for pwm map register caching 
Accessing virtual registers is very inefficient, so pwm map values
should be cached when possible, else userspace could effectively do
a DOS attack by reading pwm map values in a while loop.
Use the regmap cache to cache those values.

Tested on a Fujitsu Esprimo P720.

Signed-off-by: Armin Wolf <W_Armin@gmx.de>
Link: https://lore.kernel.org/r/20230907052639.16491-4-W_Armin@gmx.de
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2023-10-27 07:27:24 -07:00

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// SPDX-License-Identifier: GPL-2.0-or-later
/***************************************************************************
* Copyright (C) 2010-2012 Hans de Goede <hdegoede@redhat.com> *
* *
***************************************************************************/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/bits.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/pm.h>
#include <linux/init.h>
#include <linux/regmap.h>
#include <linux/slab.h>
#include <linux/jiffies.h>
#include <linux/platform_device.h>
#include <linux/hwmon.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include "sch56xx-common.h"
#define DRVNAME "sch5627"
#define DEVNAME DRVNAME /* We only support one model */
#define SCH5627_HWMON_ID 0xa5
#define SCH5627_COMPANY_ID 0x5c
#define SCH5627_PRIMARY_ID 0xa0
#define SCH5627_REG_BUILD_CODE 0x39
#define SCH5627_REG_BUILD_ID 0x3a
#define SCH5627_REG_HWMON_ID 0x3c
#define SCH5627_REG_HWMON_REV 0x3d
#define SCH5627_REG_COMPANY_ID 0x3e
#define SCH5627_REG_PRIMARY_ID 0x3f
#define SCH5627_REG_CTRL 0x40
#define SCH5627_CTRL_START BIT(0)
#define SCH5627_CTRL_LOCK BIT(1)
#define SCH5627_CTRL_VBAT BIT(4)
#define SCH5627_NO_TEMPS 8
#define SCH5627_NO_FANS 4
#define SCH5627_NO_IN 5
static const u16 SCH5627_REG_TEMP_MSB[SCH5627_NO_TEMPS] = {
0x2B, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x180, 0x181 };
static const u16 SCH5627_REG_TEMP_LSN[SCH5627_NO_TEMPS] = {
0xE2, 0xE1, 0xE1, 0xE5, 0xE5, 0xE6, 0x182, 0x182 };
static const u16 SCH5627_REG_TEMP_HIGH_NIBBLE[SCH5627_NO_TEMPS] = {
0, 0, 1, 1, 0, 0, 0, 1 };
static const u16 SCH5627_REG_TEMP_HIGH[SCH5627_NO_TEMPS] = {
0x61, 0x57, 0x59, 0x5B, 0x5D, 0x5F, 0x184, 0x186 };
static const u16 SCH5627_REG_TEMP_ABS[SCH5627_NO_TEMPS] = {
0x9B, 0x96, 0x97, 0x98, 0x99, 0x9A, 0x1A8, 0x1A9 };
static const u16 SCH5627_REG_FAN[SCH5627_NO_FANS] = {
0x2C, 0x2E, 0x30, 0x32 };
static const u16 SCH5627_REG_FAN_MIN[SCH5627_NO_FANS] = {
0x62, 0x64, 0x66, 0x68 };
static const u16 SCH5627_REG_PWM_MAP[SCH5627_NO_FANS] = {
0xA0, 0xA1, 0xA2, 0xA3 };
static const u16 SCH5627_REG_IN_MSB[SCH5627_NO_IN] = {
0x22, 0x23, 0x24, 0x25, 0x189 };
static const u16 SCH5627_REG_IN_LSN[SCH5627_NO_IN] = {
0xE4, 0xE4, 0xE3, 0xE3, 0x18A };
static const u16 SCH5627_REG_IN_HIGH_NIBBLE[SCH5627_NO_IN] = {
1, 0, 1, 0, 1 };
static const u16 SCH5627_REG_IN_FACTOR[SCH5627_NO_IN] = {
10745, 3660, 9765, 10745, 3660 };
static const char * const SCH5627_IN_LABELS[SCH5627_NO_IN] = {
"VCC", "VTT", "VBAT", "VTR", "V_IN" };
struct sch5627_data {
struct regmap *regmap;
unsigned short addr;
u8 control;
u8 temp_max[SCH5627_NO_TEMPS];
u8 temp_crit[SCH5627_NO_TEMPS];
u16 fan_min[SCH5627_NO_FANS];
struct mutex update_lock;
unsigned long last_battery; /* In jiffies */
char temp_valid; /* !=0 if following fields are valid */
char fan_valid;
char in_valid;
unsigned long temp_last_updated; /* In jiffies */
unsigned long fan_last_updated;
unsigned long in_last_updated;
u16 temp[SCH5627_NO_TEMPS];
u16 fan[SCH5627_NO_FANS];
u16 in[SCH5627_NO_IN];
};
static const struct regmap_range sch5627_tunables_ranges[] = {
regmap_reg_range(0xA0, 0xA3),
};
static const struct regmap_access_table sch5627_tunables_table = {
.yes_ranges = sch5627_tunables_ranges,
.n_yes_ranges = ARRAY_SIZE(sch5627_tunables_ranges),
};
static const struct regmap_config sch5627_regmap_config = {
.reg_bits = 16,
.val_bits = 8,
.wr_table = &sch5627_tunables_table,
.rd_table = &sch5627_tunables_table,
.cache_type = REGCACHE_RBTREE,
.use_single_read = true,
.use_single_write = true,
.can_sleep = true,
};
static int sch5627_update_temp(struct sch5627_data *data)
{
int ret = 0;
int i, val;
mutex_lock(&data->update_lock);
/* Cache the values for 1 second */
if (time_after(jiffies, data->temp_last_updated + HZ) || !data->temp_valid) {
for (i = 0; i < SCH5627_NO_TEMPS; i++) {
val = sch56xx_read_virtual_reg12(data->addr, SCH5627_REG_TEMP_MSB[i],
SCH5627_REG_TEMP_LSN[i],
SCH5627_REG_TEMP_HIGH_NIBBLE[i]);
if (unlikely(val < 0)) {
ret = val;
goto abort;
}
data->temp[i] = val;
}
data->temp_last_updated = jiffies;
data->temp_valid = 1;
}
abort:
mutex_unlock(&data->update_lock);
return ret;
}
static int sch5627_update_fan(struct sch5627_data *data)
{
int ret = 0;
int i, val;
mutex_lock(&data->update_lock);
/* Cache the values for 1 second */
if (time_after(jiffies, data->fan_last_updated + HZ) || !data->fan_valid) {
for (i = 0; i < SCH5627_NO_FANS; i++) {
val = sch56xx_read_virtual_reg16(data->addr, SCH5627_REG_FAN[i]);
if (unlikely(val < 0)) {
ret = val;
goto abort;
}
data->fan[i] = val;
}
data->fan_last_updated = jiffies;
data->fan_valid = 1;
}
abort:
mutex_unlock(&data->update_lock);
return ret;
}
static int sch5627_update_in(struct sch5627_data *data)
{
int ret = 0;
int i, val;
mutex_lock(&data->update_lock);
/* Trigger a Vbat voltage measurement every 5 minutes */
if (time_after(jiffies, data->last_battery + 300 * HZ)) {
sch56xx_write_virtual_reg(data->addr, SCH5627_REG_CTRL,
data->control | SCH5627_CTRL_VBAT);
data->last_battery = jiffies;
}
/* Cache the values for 1 second */
if (time_after(jiffies, data->in_last_updated + HZ) || !data->in_valid) {
for (i = 0; i < SCH5627_NO_IN; i++) {
val = sch56xx_read_virtual_reg12(data->addr, SCH5627_REG_IN_MSB[i],
SCH5627_REG_IN_LSN[i],
SCH5627_REG_IN_HIGH_NIBBLE[i]);
if (unlikely(val < 0)) {
ret = val;
goto abort;
}
data->in[i] = val;
}
data->in_last_updated = jiffies;
data->in_valid = 1;
}
abort:
mutex_unlock(&data->update_lock);
return ret;
}
static int sch5627_read_limits(struct sch5627_data *data)
{
int i, val;
for (i = 0; i < SCH5627_NO_TEMPS; i++) {
/*
* Note what SMSC calls ABS, is what lm_sensors calls max
* (aka high), and HIGH is what lm_sensors calls crit.
*/
val = sch56xx_read_virtual_reg(data->addr,
SCH5627_REG_TEMP_ABS[i]);
if (val < 0)
return val;
data->temp_max[i] = val;
val = sch56xx_read_virtual_reg(data->addr,
SCH5627_REG_TEMP_HIGH[i]);
if (val < 0)
return val;
data->temp_crit[i] = val;
}
for (i = 0; i < SCH5627_NO_FANS; i++) {
val = sch56xx_read_virtual_reg16(data->addr,
SCH5627_REG_FAN_MIN[i]);
if (val < 0)
return val;
data->fan_min[i] = val;
}
return 0;
}
static int reg_to_temp(u16 reg)
{
return (reg * 625) / 10 - 64000;
}
static int reg_to_temp_limit(u8 reg)
{
return (reg - 64) * 1000;
}
static int reg_to_rpm(u16 reg)
{
if (reg == 0)
return -EIO;
if (reg == 0xffff)
return 0;
return 5400540 / reg;
}
static umode_t sch5627_is_visible(const void *drvdata, enum hwmon_sensor_types type, u32 attr,
int channel)
{
const struct sch5627_data *data = drvdata;
/* Once the lock bit is set, the virtual registers become read-only
* until the next power cycle.
*/
if (data->control & SCH5627_CTRL_LOCK)
return 0444;
if (type == hwmon_pwm && attr == hwmon_pwm_auto_channels_temp)
return 0644;
return 0444;
}
static int sch5627_read(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel,
long *val)
{
struct sch5627_data *data = dev_get_drvdata(dev);
int ret, value;
switch (type) {
case hwmon_temp:
ret = sch5627_update_temp(data);
if (ret < 0)
return ret;
switch (attr) {
case hwmon_temp_input:
*val = reg_to_temp(data->temp[channel]);
return 0;
case hwmon_temp_max:
*val = reg_to_temp_limit(data->temp_max[channel]);
return 0;
case hwmon_temp_crit:
*val = reg_to_temp_limit(data->temp_crit[channel]);
return 0;
case hwmon_temp_fault:
*val = (data->temp[channel] == 0);
return 0;
default:
break;
}
break;
case hwmon_fan:
ret = sch5627_update_fan(data);
if (ret < 0)
return ret;
switch (attr) {
case hwmon_fan_input:
ret = reg_to_rpm(data->fan[channel]);
if (ret < 0)
return ret;
*val = ret;
return 0;
case hwmon_fan_min:
ret = reg_to_rpm(data->fan_min[channel]);
if (ret < 0)
return ret;
*val = ret;
return 0;
case hwmon_fan_fault:
*val = (data->fan[channel] == 0xffff);
return 0;
default:
break;
}
break;
case hwmon_pwm:
switch (attr) {
case hwmon_pwm_auto_channels_temp:
ret = regmap_read(data->regmap, SCH5627_REG_PWM_MAP[channel], &value);
if (ret < 0)
return ret;
*val = value;
return 0;
default:
break;
}
break;
case hwmon_in:
ret = sch5627_update_in(data);
if (ret < 0)
return ret;
switch (attr) {
case hwmon_in_input:
*val = DIV_ROUND_CLOSEST(data->in[channel] * SCH5627_REG_IN_FACTOR[channel],
10000);
return 0;
default:
break;
}
break;
default:
break;
}
return -EOPNOTSUPP;
}
static int sch5627_read_string(struct device *dev, enum hwmon_sensor_types type, u32 attr,
int channel, const char **str)
{
switch (type) {
case hwmon_in:
switch (attr) {
case hwmon_in_label:
*str = SCH5627_IN_LABELS[channel];
return 0;
default:
break;
}
break;
default:
break;
}
return -EOPNOTSUPP;
}
static int sch5627_write(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel,
long val)
{
struct sch5627_data *data = dev_get_drvdata(dev);
switch (type) {
case hwmon_pwm:
switch (attr) {
case hwmon_pwm_auto_channels_temp:
/* registers are 8 bit wide */
if (val > U8_MAX || val < 0)
return -EINVAL;
return regmap_write(data->regmap, SCH5627_REG_PWM_MAP[channel], val);
default:
break;
}
break;
default:
break;
}
return -EOPNOTSUPP;
}
static const struct hwmon_ops sch5627_ops = {
.is_visible = sch5627_is_visible,
.read = sch5627_read,
.read_string = sch5627_read_string,
.write = sch5627_write,
};
static const struct hwmon_channel_info * const sch5627_info[] = {
HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
HWMON_CHANNEL_INFO(temp,
HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT | HWMON_T_FAULT,
HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT | HWMON_T_FAULT,
HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT | HWMON_T_FAULT,
HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT | HWMON_T_FAULT,
HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT | HWMON_T_FAULT,
HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT | HWMON_T_FAULT,
HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT | HWMON_T_FAULT,
HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT | HWMON_T_FAULT
),
HWMON_CHANNEL_INFO(fan,
HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_FAULT,
HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_FAULT,
HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_FAULT,
HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_FAULT
),
HWMON_CHANNEL_INFO(pwm,
HWMON_PWM_AUTO_CHANNELS_TEMP,
HWMON_PWM_AUTO_CHANNELS_TEMP,
HWMON_PWM_AUTO_CHANNELS_TEMP,
HWMON_PWM_AUTO_CHANNELS_TEMP
),
HWMON_CHANNEL_INFO(in,
HWMON_I_INPUT | HWMON_I_LABEL,
HWMON_I_INPUT | HWMON_I_LABEL,
HWMON_I_INPUT | HWMON_I_LABEL,
HWMON_I_INPUT | HWMON_I_LABEL,
HWMON_I_INPUT
),
NULL
};
static const struct hwmon_chip_info sch5627_chip_info = {
.ops = &sch5627_ops,
.info = sch5627_info,
};
static int sch5627_probe(struct platform_device *pdev)
{
struct sch5627_data *data;
struct device *hwmon_dev;
int err, build_code, build_id, hwmon_rev, val;
data = devm_kzalloc(&pdev->dev, sizeof(struct sch5627_data),
GFP_KERNEL);
if (!data)
return -ENOMEM;
data->addr = platform_get_resource(pdev, IORESOURCE_IO, 0)->start;
mutex_init(&data->update_lock);
platform_set_drvdata(pdev, data);
val = sch56xx_read_virtual_reg(data->addr, SCH5627_REG_HWMON_ID);
if (val < 0)
return val;
if (val != SCH5627_HWMON_ID) {
pr_err("invalid %s id: 0x%02X (expected 0x%02X)\n", "hwmon",
val, SCH5627_HWMON_ID);
return -ENODEV;
}
val = sch56xx_read_virtual_reg(data->addr, SCH5627_REG_COMPANY_ID);
if (val < 0)
return val;
if (val != SCH5627_COMPANY_ID) {
pr_err("invalid %s id: 0x%02X (expected 0x%02X)\n", "company",
val, SCH5627_COMPANY_ID);
return -ENODEV;
}
val = sch56xx_read_virtual_reg(data->addr, SCH5627_REG_PRIMARY_ID);
if (val < 0)
return val;
if (val != SCH5627_PRIMARY_ID) {
pr_err("invalid %s id: 0x%02X (expected 0x%02X)\n", "primary",
val, SCH5627_PRIMARY_ID);
return -ENODEV;
}
build_code = sch56xx_read_virtual_reg(data->addr,
SCH5627_REG_BUILD_CODE);
if (build_code < 0)
return build_code;
build_id = sch56xx_read_virtual_reg16(data->addr,
SCH5627_REG_BUILD_ID);
if (build_id < 0)
return build_id;
hwmon_rev = sch56xx_read_virtual_reg(data->addr,
SCH5627_REG_HWMON_REV);
if (hwmon_rev < 0)
return hwmon_rev;
val = sch56xx_read_virtual_reg(data->addr, SCH5627_REG_CTRL);
if (val < 0)
return val;
data->control = val;
if (!(data->control & SCH5627_CTRL_START)) {
pr_err("hardware monitoring not enabled\n");
return -ENODEV;
}
data->regmap = devm_regmap_init_sch56xx(&pdev->dev, &data->update_lock, data->addr,
&sch5627_regmap_config);
if (IS_ERR(data->regmap))
return PTR_ERR(data->regmap);
/* Trigger a Vbat voltage measurement, so that we get a valid reading
the first time we read Vbat */
sch56xx_write_virtual_reg(data->addr, SCH5627_REG_CTRL, data->control | SCH5627_CTRL_VBAT);
data->last_battery = jiffies;
/*
* Read limits, we do this only once as reading a register on
* the sch5627 is quite expensive (and they don't change).
*/
err = sch5627_read_limits(data);
if (err)
return err;
pr_info("found %s chip at %#hx\n", DEVNAME, data->addr);
pr_info("firmware build: code 0x%02X, id 0x%04X, hwmon: rev 0x%02X\n",
build_code, build_id, hwmon_rev);
hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev, DEVNAME, data,
&sch5627_chip_info, NULL);
if (IS_ERR(hwmon_dev))
return PTR_ERR(hwmon_dev);
/* Note failing to register the watchdog is not a fatal error */
sch56xx_watchdog_register(&pdev->dev, data->addr,
(build_code << 24) | (build_id << 8) | hwmon_rev,
&data->update_lock, 1);
return 0;
}
static int sch5627_suspend(struct device *dev)
{
struct sch5627_data *data = dev_get_drvdata(dev);
regcache_cache_only(data->regmap, true);
regcache_mark_dirty(data->regmap);
return 0;
}
static int sch5627_resume(struct device *dev)
{
struct sch5627_data *data = dev_get_drvdata(dev);
regcache_cache_only(data->regmap, false);
/* We must not access the virtual registers when the lock bit is set */
if (data->control & SCH5627_CTRL_LOCK)
return regcache_drop_region(data->regmap, 0, U16_MAX);
return regcache_sync(data->regmap);
}
static DEFINE_SIMPLE_DEV_PM_OPS(sch5627_dev_pm_ops, sch5627_suspend, sch5627_resume);
static const struct platform_device_id sch5627_device_id[] = {
{
.name = "sch5627",
},
{ }
};
MODULE_DEVICE_TABLE(platform, sch5627_device_id);
static struct platform_driver sch5627_driver = {
.driver = {
.name = DRVNAME,
.pm = pm_sleep_ptr(&sch5627_dev_pm_ops),
},
.probe = sch5627_probe,
.id_table = sch5627_device_id,
};
module_platform_driver(sch5627_driver);
MODULE_DESCRIPTION("SMSC SCH5627 Hardware Monitoring Driver");
MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
MODULE_LICENSE("GPL");
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