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linux/drivers/hwmon/i5k_amb.c
Saheed O. Bolarinwa 2207515db6 hwmon: (i5k_amb, vt8231) Drop uses of pci_read_config_*() return value 
The return value of pci_read_config_*() may not indicate a device error.
However, the value read by these functions is more likely to indicate
this kind of error. This presents two overlapping ways of reporting
errors and complicates error checking.

It is possible to move to one single way of checking for error if the
dependency on the return value of these functions is removed, then it
can later be made to return void.

Remove all uses of the return value of pci_read_config_*().
Check the actual value read for ~0. In this case, ~0 is an invalid
value thus it indicates some kind of error.

Suggested-by: Bjorn Helgaas <bjorn@helgaas.com>
Signed-off-by: Saheed O. Bolarinwa <refactormyself@gmail.com>
Link: https://lore.kernel.org/r/20200801112446.149549-11-refactormyself@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2020-08-04 14:24:39 -07:00

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* A hwmon driver for the Intel 5000 series chipset FB-DIMM AMB
* temperature sensors
* Copyright (C) 2007 IBM
*
* Author: Darrick J. Wong <darrick.wong@oracle.com>
*/
#include <linux/module.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/log2.h>
#include <linux/pci.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#define DRVNAME "i5k_amb"
#define I5K_REG_AMB_BASE_ADDR 0x48
#define I5K_REG_AMB_LEN_ADDR 0x50
#define I5K_REG_CHAN0_PRESENCE_ADDR 0x64
#define I5K_REG_CHAN1_PRESENCE_ADDR 0x66
#define AMB_REG_TEMP_MIN_ADDR 0x80
#define AMB_REG_TEMP_MID_ADDR 0x81
#define AMB_REG_TEMP_MAX_ADDR 0x82
#define AMB_REG_TEMP_STATUS_ADDR 0x84
#define AMB_REG_TEMP_ADDR 0x85
#define AMB_CONFIG_SIZE 2048
#define AMB_FUNC_3_OFFSET 768
static unsigned long amb_reg_temp_status(unsigned int amb)
{
return AMB_FUNC_3_OFFSET + AMB_REG_TEMP_STATUS_ADDR +
AMB_CONFIG_SIZE * amb;
}
static unsigned long amb_reg_temp_min(unsigned int amb)
{
return AMB_FUNC_3_OFFSET + AMB_REG_TEMP_MIN_ADDR +
AMB_CONFIG_SIZE * amb;
}
static unsigned long amb_reg_temp_mid(unsigned int amb)
{
return AMB_FUNC_3_OFFSET + AMB_REG_TEMP_MID_ADDR +
AMB_CONFIG_SIZE * amb;
}
static unsigned long amb_reg_temp_max(unsigned int amb)
{
return AMB_FUNC_3_OFFSET + AMB_REG_TEMP_MAX_ADDR +
AMB_CONFIG_SIZE * amb;
}
static unsigned long amb_reg_temp(unsigned int amb)
{
return AMB_FUNC_3_OFFSET + AMB_REG_TEMP_ADDR +
AMB_CONFIG_SIZE * amb;
}
#define MAX_MEM_CHANNELS 4
#define MAX_AMBS_PER_CHANNEL 16
#define MAX_AMBS (MAX_MEM_CHANNELS * \
MAX_AMBS_PER_CHANNEL)
#define CHANNEL_SHIFT 4
#define DIMM_MASK 0xF
/*
* Ugly hack: For some reason the highest bit is set if there
* are _any_ DIMMs in the channel. Attempting to read from
* this "high-order" AMB results in a memory bus error, so
* for now we'll just ignore that top bit, even though that
* might prevent us from seeing the 16th DIMM in the channel.
*/
#define REAL_MAX_AMBS_PER_CHANNEL 15
#define KNOBS_PER_AMB 6
static unsigned long amb_num_from_reg(unsigned int byte_num, unsigned int bit)
{
return byte_num * MAX_AMBS_PER_CHANNEL + bit;
}
#define AMB_SYSFS_NAME_LEN 16
struct i5k_device_attribute {
struct sensor_device_attribute s_attr;
char name[AMB_SYSFS_NAME_LEN];
};
struct i5k_amb_data {
struct device *hwmon_dev;
unsigned long amb_base;
unsigned long amb_len;
u16 amb_present[MAX_MEM_CHANNELS];
void __iomem *amb_mmio;
struct i5k_device_attribute *attrs;
unsigned int num_attrs;
};
static ssize_t name_show(struct device *dev, struct device_attribute *devattr,
char *buf)
{
return sprintf(buf, "%s\n", DRVNAME);
}
static DEVICE_ATTR_RO(name);
static struct platform_device *amb_pdev;
static u8 amb_read_byte(struct i5k_amb_data *data, unsigned long offset)
{
return ioread8(data->amb_mmio + offset);
}
static void amb_write_byte(struct i5k_amb_data *data, unsigned long offset,
u8 val)
{
iowrite8(val, data->amb_mmio + offset);
}
static ssize_t show_amb_alarm(struct device *dev,
struct device_attribute *devattr,
char *buf)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
struct i5k_amb_data *data = dev_get_drvdata(dev);
if (!(amb_read_byte(data, amb_reg_temp_status(attr->index)) & 0x20) &&
(amb_read_byte(data, amb_reg_temp_status(attr->index)) & 0x8))
return sprintf(buf, "1\n");
else
return sprintf(buf, "0\n");
}
static ssize_t store_amb_min(struct device *dev,
struct device_attribute *devattr,
const char *buf,
size_t count)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
struct i5k_amb_data *data = dev_get_drvdata(dev);
unsigned long temp;
int ret = kstrtoul(buf, 10, &temp);
if (ret < 0)
return ret;
temp = temp / 500;
if (temp > 255)
temp = 255;
amb_write_byte(data, amb_reg_temp_min(attr->index), temp);
return count;
}
static ssize_t store_amb_mid(struct device *dev,
struct device_attribute *devattr,
const char *buf,
size_t count)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
struct i5k_amb_data *data = dev_get_drvdata(dev);
unsigned long temp;
int ret = kstrtoul(buf, 10, &temp);
if (ret < 0)
return ret;
temp = temp / 500;
if (temp > 255)
temp = 255;
amb_write_byte(data, amb_reg_temp_mid(attr->index), temp);
return count;
}
static ssize_t store_amb_max(struct device *dev,
struct device_attribute *devattr,
const char *buf,
size_t count)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
struct i5k_amb_data *data = dev_get_drvdata(dev);
unsigned long temp;
int ret = kstrtoul(buf, 10, &temp);
if (ret < 0)
return ret;
temp = temp / 500;
if (temp > 255)
temp = 255;
amb_write_byte(data, amb_reg_temp_max(attr->index), temp);
return count;
}
static ssize_t show_amb_min(struct device *dev,
struct device_attribute *devattr,
char *buf)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
struct i5k_amb_data *data = dev_get_drvdata(dev);
return sprintf(buf, "%d\n",
500 * amb_read_byte(data, amb_reg_temp_min(attr->index)));
}
static ssize_t show_amb_mid(struct device *dev,
struct device_attribute *devattr,
char *buf)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
struct i5k_amb_data *data = dev_get_drvdata(dev);
return sprintf(buf, "%d\n",
500 * amb_read_byte(data, amb_reg_temp_mid(attr->index)));
}
static ssize_t show_amb_max(struct device *dev,
struct device_attribute *devattr,
char *buf)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
struct i5k_amb_data *data = dev_get_drvdata(dev);
return sprintf(buf, "%d\n",
500 * amb_read_byte(data, amb_reg_temp_max(attr->index)));
}
static ssize_t show_amb_temp(struct device *dev,
struct device_attribute *devattr,
char *buf)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
struct i5k_amb_data *data = dev_get_drvdata(dev);
return sprintf(buf, "%d\n",
500 * amb_read_byte(data, amb_reg_temp(attr->index)));
}
static ssize_t show_label(struct device *dev,
struct device_attribute *devattr,
char *buf)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
return sprintf(buf, "Ch. %d DIMM %d\n", attr->index >> CHANNEL_SHIFT,
attr->index & DIMM_MASK);
}
static int i5k_amb_hwmon_init(struct platform_device *pdev)
{
int i, j, k, d = 0;
u16 c;
int res = 0;
int num_ambs = 0;
struct i5k_amb_data *data = platform_get_drvdata(pdev);
/* Count the number of AMBs found */
/* ignore the high-order bit, see "Ugly hack" comment above */
for (i = 0; i < MAX_MEM_CHANNELS; i++)
num_ambs += hweight16(data->amb_present[i] & 0x7fff);
/* Set up sysfs stuff */
data->attrs = kzalloc(array3_size(num_ambs, KNOBS_PER_AMB,
sizeof(*data->attrs)),
GFP_KERNEL);
if (!data->attrs)
return -ENOMEM;
data->num_attrs = 0;
for (i = 0; i < MAX_MEM_CHANNELS; i++) {
c = data->amb_present[i];
for (j = 0; j < REAL_MAX_AMBS_PER_CHANNEL; j++, c >>= 1) {
struct i5k_device_attribute *iattr;
k = amb_num_from_reg(i, j);
if (!(c & 0x1))
continue;
d++;
/* sysfs label */
iattr = data->attrs + data->num_attrs;
snprintf(iattr->name, AMB_SYSFS_NAME_LEN,
"temp%d_label", d);
iattr->s_attr.dev_attr.attr.name = iattr->name;
iattr->s_attr.dev_attr.attr.mode = 0444;
iattr->s_attr.dev_attr.show = show_label;
iattr->s_attr.index = k;
sysfs_attr_init(&iattr->s_attr.dev_attr.attr);
res = device_create_file(&pdev->dev,
&iattr->s_attr.dev_attr);
if (res)
goto exit_remove;
data->num_attrs++;
/* Temperature sysfs knob */
iattr = data->attrs + data->num_attrs;
snprintf(iattr->name, AMB_SYSFS_NAME_LEN,
"temp%d_input", d);
iattr->s_attr.dev_attr.attr.name = iattr->name;
iattr->s_attr.dev_attr.attr.mode = 0444;
iattr->s_attr.dev_attr.show = show_amb_temp;
iattr->s_attr.index = k;
sysfs_attr_init(&iattr->s_attr.dev_attr.attr);
res = device_create_file(&pdev->dev,
&iattr->s_attr.dev_attr);
if (res)
goto exit_remove;
data->num_attrs++;
/* Temperature min sysfs knob */
iattr = data->attrs + data->num_attrs;
snprintf(iattr->name, AMB_SYSFS_NAME_LEN,
"temp%d_min", d);
iattr->s_attr.dev_attr.attr.name = iattr->name;
iattr->s_attr.dev_attr.attr.mode = 0644;
iattr->s_attr.dev_attr.show = show_amb_min;
iattr->s_attr.dev_attr.store = store_amb_min;
iattr->s_attr.index = k;
sysfs_attr_init(&iattr->s_attr.dev_attr.attr);
res = device_create_file(&pdev->dev,
&iattr->s_attr.dev_attr);
if (res)
goto exit_remove;
data->num_attrs++;
/* Temperature mid sysfs knob */
iattr = data->attrs + data->num_attrs;
snprintf(iattr->name, AMB_SYSFS_NAME_LEN,
"temp%d_mid", d);
iattr->s_attr.dev_attr.attr.name = iattr->name;
iattr->s_attr.dev_attr.attr.mode = 0644;
iattr->s_attr.dev_attr.show = show_amb_mid;
iattr->s_attr.dev_attr.store = store_amb_mid;
iattr->s_attr.index = k;
sysfs_attr_init(&iattr->s_attr.dev_attr.attr);
res = device_create_file(&pdev->dev,
&iattr->s_attr.dev_attr);
if (res)
goto exit_remove;
data->num_attrs++;
/* Temperature max sysfs knob */
iattr = data->attrs + data->num_attrs;
snprintf(iattr->name, AMB_SYSFS_NAME_LEN,
"temp%d_max", d);
iattr->s_attr.dev_attr.attr.name = iattr->name;
iattr->s_attr.dev_attr.attr.mode = 0644;
iattr->s_attr.dev_attr.show = show_amb_max;
iattr->s_attr.dev_attr.store = store_amb_max;
iattr->s_attr.index = k;
sysfs_attr_init(&iattr->s_attr.dev_attr.attr);
res = device_create_file(&pdev->dev,
&iattr->s_attr.dev_attr);
if (res)
goto exit_remove;
data->num_attrs++;
/* Temperature alarm sysfs knob */
iattr = data->attrs + data->num_attrs;
snprintf(iattr->name, AMB_SYSFS_NAME_LEN,
"temp%d_alarm", d);
iattr->s_attr.dev_attr.attr.name = iattr->name;
iattr->s_attr.dev_attr.attr.mode = 0444;
iattr->s_attr.dev_attr.show = show_amb_alarm;
iattr->s_attr.index = k;
sysfs_attr_init(&iattr->s_attr.dev_attr.attr);
res = device_create_file(&pdev->dev,
&iattr->s_attr.dev_attr);
if (res)
goto exit_remove;
data->num_attrs++;
}
}
res = device_create_file(&pdev->dev, &dev_attr_name);
if (res)
goto exit_remove;
data->hwmon_dev = hwmon_device_register(&pdev->dev);
if (IS_ERR(data->hwmon_dev)) {
res = PTR_ERR(data->hwmon_dev);
goto exit_remove;
}
return res;
exit_remove:
device_remove_file(&pdev->dev, &dev_attr_name);
for (i = 0; i < data->num_attrs; i++)
device_remove_file(&pdev->dev, &data->attrs[i].s_attr.dev_attr);
kfree(data->attrs);
return res;
}
static int i5k_amb_add(void)
{
int res;
/* only ever going to be one of these */
amb_pdev = platform_device_alloc(DRVNAME, 0);
if (!amb_pdev)
return -ENOMEM;
res = platform_device_add(amb_pdev);
if (res)
goto err;
return 0;
err:
platform_device_put(amb_pdev);
return res;
}
static int i5k_find_amb_registers(struct i5k_amb_data *data,
unsigned long devid)
{
struct pci_dev *pcidev;
u32 val32;
int res = -ENODEV;
/* Find AMB register memory space */
pcidev = pci_get_device(PCI_VENDOR_ID_INTEL,
devid,
NULL);
if (!pcidev)
return -ENODEV;
pci_read_config_dword(pcidev, I5K_REG_AMB_BASE_ADDR, &val32);
if (val32 == (u32)~0)
goto out;
data->amb_base = val32;
pci_read_config_dword(pcidev, I5K_REG_AMB_LEN_ADDR, &val32);
if (val32 == (u32)~0)
goto out;
data->amb_len = val32;
/* Is it big enough? */
if (data->amb_len < AMB_CONFIG_SIZE * MAX_AMBS) {
dev_err(&pcidev->dev, "AMB region too small!\n");
goto out;
}
res = 0;
out:
pci_dev_put(pcidev);
return res;
}
static int i5k_channel_probe(u16 *amb_present, unsigned long dev_id)
{
struct pci_dev *pcidev;
u16 val16;
int res = -ENODEV;
/* Copy the DIMM presence map for these two channels */
pcidev = pci_get_device(PCI_VENDOR_ID_INTEL, dev_id, NULL);
if (!pcidev)
return -ENODEV;
pci_read_config_word(pcidev, I5K_REG_CHAN0_PRESENCE_ADDR, &val16);
if (val16 == (u16)~0)
goto out;
amb_present[0] = val16;
pci_read_config_word(pcidev, I5K_REG_CHAN1_PRESENCE_ADDR, &val16);
if (val16 == (u16)~0)
goto out;
amb_present[1] = val16;
res = 0;
out:
pci_dev_put(pcidev);
return res;
}
static struct {
unsigned long err;
unsigned long fbd0;
} chipset_ids[] = {
{ PCI_DEVICE_ID_INTEL_5000_ERR, PCI_DEVICE_ID_INTEL_5000_FBD0 },
{ PCI_DEVICE_ID_INTEL_5400_ERR, PCI_DEVICE_ID_INTEL_5400_FBD0 },
{ 0, 0 }
};
#ifdef MODULE
static const struct pci_device_id i5k_amb_ids[] = {
{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_5000_ERR) },
{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_5400_ERR) },
{ 0, }
};
MODULE_DEVICE_TABLE(pci, i5k_amb_ids);
#endif
static int i5k_amb_probe(struct platform_device *pdev)
{
struct i5k_amb_data *data;
struct resource *reso;
int i, res;
data = kzalloc(sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
/* Figure out where the AMB registers live */
i = 0;
do {
res = i5k_find_amb_registers(data, chipset_ids[i].err);
if (res == 0)
break;
i++;
} while (chipset_ids[i].err);
if (res)
goto err;
/* Copy the DIMM presence map for the first two channels */
res = i5k_channel_probe(&data->amb_present[0], chipset_ids[i].fbd0);
if (res)
goto err;
/* Copy the DIMM presence map for the optional second two channels */
i5k_channel_probe(&data->amb_present[2], chipset_ids[i].fbd0 + 1);
/* Set up resource regions */
reso = request_mem_region(data->amb_base, data->amb_len, DRVNAME);
if (!reso) {
res = -EBUSY;
goto err;
}
data->amb_mmio = ioremap(data->amb_base, data->amb_len);
if (!data->amb_mmio) {
res = -EBUSY;
goto err_map_failed;
}
platform_set_drvdata(pdev, data);
res = i5k_amb_hwmon_init(pdev);
if (res)
goto err_init_failed;
return res;
err_init_failed:
iounmap(data->amb_mmio);
err_map_failed:
release_mem_region(data->amb_base, data->amb_len);
err:
kfree(data);
return res;
}
static int i5k_amb_remove(struct platform_device *pdev)
{
int i;
struct i5k_amb_data *data = platform_get_drvdata(pdev);
hwmon_device_unregister(data->hwmon_dev);
device_remove_file(&pdev->dev, &dev_attr_name);
for (i = 0; i < data->num_attrs; i++)
device_remove_file(&pdev->dev, &data->attrs[i].s_attr.dev_attr);
kfree(data->attrs);
iounmap(data->amb_mmio);
release_mem_region(data->amb_base, data->amb_len);
kfree(data);
return 0;
}
static struct platform_driver i5k_amb_driver = {
.driver = {
.name = DRVNAME,
},
.probe = i5k_amb_probe,
.remove = i5k_amb_remove,
};
static int __init i5k_amb_init(void)
{
int res;
res = platform_driver_register(&i5k_amb_driver);
if (res)
return res;
res = i5k_amb_add();
if (res)
platform_driver_unregister(&i5k_amb_driver);
return res;
}
static void __exit i5k_amb_exit(void)
{
platform_device_unregister(amb_pdev);
platform_driver_unregister(&i5k_amb_driver);
}
MODULE_AUTHOR("Darrick J. Wong <darrick.wong@oracle.com>");
MODULE_DESCRIPTION("Intel 5000 chipset FB-DIMM AMB temperature sensor");
MODULE_LICENSE("GPL");
module_init(i5k_amb_init);
module_exit(i5k_amb_exit);
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