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linux-next/drivers/misc/eeprom/eeprom.c
Thomas Gleixner c942fddf87 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157
Based on 3 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version this program is distributed in the
  hope that it will be useful but without any warranty without even
  the implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version [author] [kishon] [vijay] [abraham]
  [i] [kishon]@[ti] [com] this program is distributed in the hope that
  it will be useful but without any warranty without even the implied
  warranty of merchantability or fitness for a particular purpose see
  the gnu general public license for more details

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version [author] [graeme] [gregory]
  [gg]@[slimlogic] [co] [uk] [author] [kishon] [vijay] [abraham] [i]
  [kishon]@[ti] [com] [based] [on] [twl6030]_[usb] [c] [author] [hema]
  [hk] [hemahk]@[ti] [com] this program is distributed in the hope
  that it will be useful but without any warranty without even the
  implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1105 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.202006027@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:26:37 -07:00

214 lines
5.8 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 1998, 1999 Frodo Looijaard <frodol@dds.nl> and
* Philip Edelbrock <phil@netroedge.com>
* Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com>
* Copyright (C) 2003 IBM Corp.
* Copyright (C) 2004 Jean Delvare <jdelvare@suse.de>
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/capability.h>
#include <linux/jiffies.h>
#include <linux/i2c.h>
#include <linux/mutex.h>
/* Addresses to scan */
static const unsigned short normal_i2c[] = { 0x50, 0x51, 0x52, 0x53, 0x54,
0x55, 0x56, 0x57, I2C_CLIENT_END };
/* Size of EEPROM in bytes */
#define EEPROM_SIZE 256
/* possible types of eeprom devices */
enum eeprom_nature {
UNKNOWN,
VAIO,
};
/* Each client has this additional data */
struct eeprom_data {
struct mutex update_lock;
u8 valid; /* bitfield, bit!=0 if slice is valid */
unsigned long last_updated[8]; /* In jiffies, 8 slices */
u8 data[EEPROM_SIZE]; /* Register values */
enum eeprom_nature nature;
};
static void eeprom_update_client(struct i2c_client *client, u8 slice)
{
struct eeprom_data *data = i2c_get_clientdata(client);
int i;
mutex_lock(&data->update_lock);
if (!(data->valid & (1 << slice)) ||
time_after(jiffies, data->last_updated[slice] + 300 * HZ)) {
dev_dbg(&client->dev, "Starting eeprom update, slice %u\n", slice);
if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
for (i = slice << 5; i < (slice + 1) << 5; i += 32)
if (i2c_smbus_read_i2c_block_data(client, i,
32, data->data + i)
!= 32)
goto exit;
} else {
for (i = slice << 5; i < (slice + 1) << 5; i += 2) {
int word = i2c_smbus_read_word_data(client, i);
if (word < 0)
goto exit;
data->data[i] = word & 0xff;
data->data[i + 1] = word >> 8;
}
}
data->last_updated[slice] = jiffies;
data->valid |= (1 << slice);
}
exit:
mutex_unlock(&data->update_lock);
}
static ssize_t eeprom_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t off, size_t count)
{
struct i2c_client *client = to_i2c_client(kobj_to_dev(kobj));
struct eeprom_data *data = i2c_get_clientdata(client);
u8 slice;
/* Only refresh slices which contain requested bytes */
for (slice = off >> 5; slice <= (off + count - 1) >> 5; slice++)
eeprom_update_client(client, slice);
/* Hide Vaio private settings to regular users:
- BIOS passwords: bytes 0x00 to 0x0f
- UUID: bytes 0x10 to 0x1f
- Serial number: 0xc0 to 0xdf */
if (data->nature == VAIO && !capable(CAP_SYS_ADMIN)) {
int i;
for (i = 0; i < count; i++) {
if ((off + i <= 0x1f) ||
(off + i >= 0xc0 && off + i <= 0xdf))
buf[i] = 0;
else
buf[i] = data->data[off + i];
}
} else {
memcpy(buf, &data->data[off], count);
}
return count;
}
static const struct bin_attribute eeprom_attr = {
.attr = {
.name = "eeprom",
.mode = S_IRUGO,
},
.size = EEPROM_SIZE,
.read = eeprom_read,
};
/* Return 0 if detection is successful, -ENODEV otherwise */
static int eeprom_detect(struct i2c_client *client, struct i2c_board_info *info)
{
struct i2c_adapter *adapter = client->adapter;
/* EDID EEPROMs are often 24C00 EEPROMs, which answer to all
addresses 0x50-0x57, but we only care about 0x50. So decline
attaching to addresses >= 0x51 on DDC buses */
if (!(adapter->class & I2C_CLASS_SPD) && client->addr >= 0x51)
return -ENODEV;
/* There are four ways we can read the EEPROM data:
(1) I2C block reads (faster, but unsupported by most adapters)
(2) Word reads (128% overhead)
(3) Consecutive byte reads (88% overhead, unsafe)
(4) Regular byte data reads (265% overhead)
The third and fourth methods are not implemented by this driver
because all known adapters support one of the first two. */
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_WORD_DATA)
&& !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
return -ENODEV;
strlcpy(info->type, "eeprom", I2C_NAME_SIZE);
return 0;
}
static int eeprom_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct i2c_adapter *adapter = client->adapter;
struct eeprom_data *data;
data = devm_kzalloc(&client->dev, sizeof(struct eeprom_data),
GFP_KERNEL);
if (!data)
return -ENOMEM;
memset(data->data, 0xff, EEPROM_SIZE);
i2c_set_clientdata(client, data);
mutex_init(&data->update_lock);
data->nature = UNKNOWN;
/* Detect the Vaio nature of EEPROMs.
We use the "PCG-" or "VGN-" prefix as the signature. */
if (client->addr == 0x57
&& i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
char name[4];
name[0] = i2c_smbus_read_byte_data(client, 0x80);
name[1] = i2c_smbus_read_byte_data(client, 0x81);
name[2] = i2c_smbus_read_byte_data(client, 0x82);
name[3] = i2c_smbus_read_byte_data(client, 0x83);
if (!memcmp(name, "PCG-", 4) || !memcmp(name, "VGN-", 4)) {
dev_info(&client->dev, "Vaio EEPROM detected, "
"enabling privacy protection\n");
data->nature = VAIO;
}
}
/* create the sysfs eeprom file */
return sysfs_create_bin_file(&client->dev.kobj, &eeprom_attr);
}
static int eeprom_remove(struct i2c_client *client)
{
sysfs_remove_bin_file(&client->dev.kobj, &eeprom_attr);
return 0;
}
static const struct i2c_device_id eeprom_id[] = {
{ "eeprom", 0 },
{ }
};
static struct i2c_driver eeprom_driver = {
.driver = {
.name = "eeprom",
},
.probe = eeprom_probe,
.remove = eeprom_remove,
.id_table = eeprom_id,
.class = I2C_CLASS_DDC | I2C_CLASS_SPD,
.detect = eeprom_detect,
.address_list = normal_i2c,
};
module_i2c_driver(eeprom_driver);
MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
"Philip Edelbrock <phil@netroedge.com> and "
"Greg Kroah-Hartman <greg@kroah.com>");
MODULE_DESCRIPTION("I2C EEPROM driver");
MODULE_LICENSE("GPL");