linux/drivers/misc/eeprom/at25.c
Mark Brown 96b2a45c66 eeprom: at25: Fix SPI device leak
The at25 driver is using spi_dev_get() apparently just to take a copy
of the SPI device used to instantiate it but never calls spi_dev_put()
to free it.  Since the device is guaranteed to exist between probe() and
remove() there should be no need for the driver to take an extra
reference to it so fix the leak by just using a straight assignment.

Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-05-01 14:04:19 -07:00

414 lines
10 KiB
C

/*
* at25.c -- support most SPI EEPROMs, such as Atmel AT25 models
*
* Copyright (C) 2006 David Brownell
*
* 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.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/sched.h>
#include <linux/nvmem-provider.h>
#include <linux/spi/spi.h>
#include <linux/spi/eeprom.h>
#include <linux/property.h>
/*
* NOTE: this is an *EEPROM* driver. The vagaries of product naming
* mean that some AT25 products are EEPROMs, and others are FLASH.
* Handle FLASH chips with the drivers/mtd/devices/m25p80.c driver,
* not this one!
*/
struct at25_data {
struct spi_device *spi;
struct mutex lock;
struct spi_eeprom chip;
unsigned addrlen;
struct nvmem_config nvmem_config;
struct nvmem_device *nvmem;
};
#define AT25_WREN 0x06 /* latch the write enable */
#define AT25_WRDI 0x04 /* reset the write enable */
#define AT25_RDSR 0x05 /* read status register */
#define AT25_WRSR 0x01 /* write status register */
#define AT25_READ 0x03 /* read byte(s) */
#define AT25_WRITE 0x02 /* write byte(s)/sector */
#define AT25_SR_nRDY 0x01 /* nRDY = write-in-progress */
#define AT25_SR_WEN 0x02 /* write enable (latched) */
#define AT25_SR_BP0 0x04 /* BP for software writeprotect */
#define AT25_SR_BP1 0x08
#define AT25_SR_WPEN 0x80 /* writeprotect enable */
#define AT25_INSTR_BIT3 0x08 /* Additional address bit in instr */
#define EE_MAXADDRLEN 3 /* 24 bit addresses, up to 2 MBytes */
/* Specs often allow 5 msec for a page write, sometimes 20 msec;
* it's important to recover from write timeouts.
*/
#define EE_TIMEOUT 25
/*-------------------------------------------------------------------------*/
#define io_limit PAGE_SIZE /* bytes */
static int at25_ee_read(void *priv, unsigned int offset,
void *val, size_t count)
{
struct at25_data *at25 = priv;
char *buf = val;
u8 command[EE_MAXADDRLEN + 1];
u8 *cp;
ssize_t status;
struct spi_transfer t[2];
struct spi_message m;
u8 instr;
if (unlikely(offset >= at25->chip.byte_len))
return -EINVAL;
if ((offset + count) > at25->chip.byte_len)
count = at25->chip.byte_len - offset;
if (unlikely(!count))
return -EINVAL;
cp = command;
instr = AT25_READ;
if (at25->chip.flags & EE_INSTR_BIT3_IS_ADDR)
if (offset >= (1U << (at25->addrlen * 8)))
instr |= AT25_INSTR_BIT3;
*cp++ = instr;
/* 8/16/24-bit address is written MSB first */
switch (at25->addrlen) {
default: /* case 3 */
*cp++ = offset >> 16;
case 2:
*cp++ = offset >> 8;
case 1:
case 0: /* can't happen: for better codegen */
*cp++ = offset >> 0;
}
spi_message_init(&m);
memset(t, 0, sizeof t);
t[0].tx_buf = command;
t[0].len = at25->addrlen + 1;
spi_message_add_tail(&t[0], &m);
t[1].rx_buf = buf;
t[1].len = count;
spi_message_add_tail(&t[1], &m);
mutex_lock(&at25->lock);
/* Read it all at once.
*
* REVISIT that's potentially a problem with large chips, if
* other devices on the bus need to be accessed regularly or
* this chip is clocked very slowly
*/
status = spi_sync(at25->spi, &m);
dev_dbg(&at25->spi->dev,
"read %Zd bytes at %d --> %d\n",
count, offset, (int) status);
mutex_unlock(&at25->lock);
return status;
}
static int at25_ee_write(void *priv, unsigned int off, void *val, size_t count)
{
struct at25_data *at25 = priv;
const char *buf = val;
int status = 0;
unsigned buf_size;
u8 *bounce;
if (unlikely(off >= at25->chip.byte_len))
return -EFBIG;
if ((off + count) > at25->chip.byte_len)
count = at25->chip.byte_len - off;
if (unlikely(!count))
return -EINVAL;
/* Temp buffer starts with command and address */
buf_size = at25->chip.page_size;
if (buf_size > io_limit)
buf_size = io_limit;
bounce = kmalloc(buf_size + at25->addrlen + 1, GFP_KERNEL);
if (!bounce)
return -ENOMEM;
/* For write, rollover is within the page ... so we write at
* most one page, then manually roll over to the next page.
*/
mutex_lock(&at25->lock);
do {
unsigned long timeout, retries;
unsigned segment;
unsigned offset = (unsigned) off;
u8 *cp = bounce;
int sr;
u8 instr;
*cp = AT25_WREN;
status = spi_write(at25->spi, cp, 1);
if (status < 0) {
dev_dbg(&at25->spi->dev, "WREN --> %d\n",
(int) status);
break;
}
instr = AT25_WRITE;
if (at25->chip.flags & EE_INSTR_BIT3_IS_ADDR)
if (offset >= (1U << (at25->addrlen * 8)))
instr |= AT25_INSTR_BIT3;
*cp++ = instr;
/* 8/16/24-bit address is written MSB first */
switch (at25->addrlen) {
default: /* case 3 */
*cp++ = offset >> 16;
case 2:
*cp++ = offset >> 8;
case 1:
case 0: /* can't happen: for better codegen */
*cp++ = offset >> 0;
}
/* Write as much of a page as we can */
segment = buf_size - (offset % buf_size);
if (segment > count)
segment = count;
memcpy(cp, buf, segment);
status = spi_write(at25->spi, bounce,
segment + at25->addrlen + 1);
dev_dbg(&at25->spi->dev,
"write %u bytes at %u --> %d\n",
segment, offset, (int) status);
if (status < 0)
break;
/* REVISIT this should detect (or prevent) failed writes
* to readonly sections of the EEPROM...
*/
/* Wait for non-busy status */
timeout = jiffies + msecs_to_jiffies(EE_TIMEOUT);
retries = 0;
do {
sr = spi_w8r8(at25->spi, AT25_RDSR);
if (sr < 0 || (sr & AT25_SR_nRDY)) {
dev_dbg(&at25->spi->dev,
"rdsr --> %d (%02x)\n", sr, sr);
/* at HZ=100, this is sloooow */
msleep(1);
continue;
}
if (!(sr & AT25_SR_nRDY))
break;
} while (retries++ < 3 || time_before_eq(jiffies, timeout));
if ((sr < 0) || (sr & AT25_SR_nRDY)) {
dev_err(&at25->spi->dev,
"write %d bytes offset %d, "
"timeout after %u msecs\n",
segment, offset,
jiffies_to_msecs(jiffies -
(timeout - EE_TIMEOUT)));
status = -ETIMEDOUT;
break;
}
off += segment;
buf += segment;
count -= segment;
} while (count > 0);
mutex_unlock(&at25->lock);
kfree(bounce);
return status;
}
/*-------------------------------------------------------------------------*/
static int at25_fw_to_chip(struct device *dev, struct spi_eeprom *chip)
{
u32 val;
memset(chip, 0, sizeof(*chip));
strncpy(chip->name, "at25", sizeof(chip->name));
if (device_property_read_u32(dev, "size", &val) == 0 ||
device_property_read_u32(dev, "at25,byte-len", &val) == 0) {
chip->byte_len = val;
} else {
dev_err(dev, "Error: missing \"size\" property\n");
return -ENODEV;
}
if (device_property_read_u32(dev, "pagesize", &val) == 0 ||
device_property_read_u32(dev, "at25,page-size", &val) == 0) {
chip->page_size = (u16)val;
} else {
dev_err(dev, "Error: missing \"pagesize\" property\n");
return -ENODEV;
}
if (device_property_read_u32(dev, "at25,addr-mode", &val) == 0) {
chip->flags = (u16)val;
} else {
if (device_property_read_u32(dev, "address-width", &val)) {
dev_err(dev,
"Error: missing \"address-width\" property\n");
return -ENODEV;
}
switch (val) {
case 8:
chip->flags |= EE_ADDR1;
break;
case 16:
chip->flags |= EE_ADDR2;
break;
case 24:
chip->flags |= EE_ADDR3;
break;
default:
dev_err(dev,
"Error: bad \"address-width\" property: %u\n",
val);
return -ENODEV;
}
if (device_property_present(dev, "read-only"))
chip->flags |= EE_READONLY;
}
return 0;
}
static int at25_probe(struct spi_device *spi)
{
struct at25_data *at25 = NULL;
struct spi_eeprom chip;
int err;
int sr;
int addrlen;
/* Chip description */
if (!spi->dev.platform_data) {
err = at25_fw_to_chip(&spi->dev, &chip);
if (err)
return err;
} else
chip = *(struct spi_eeprom *)spi->dev.platform_data;
/* For now we only support 8/16/24 bit addressing */
if (chip.flags & EE_ADDR1)
addrlen = 1;
else if (chip.flags & EE_ADDR2)
addrlen = 2;
else if (chip.flags & EE_ADDR3)
addrlen = 3;
else {
dev_dbg(&spi->dev, "unsupported address type\n");
return -EINVAL;
}
/* Ping the chip ... the status register is pretty portable,
* unlike probing manufacturer IDs. We do expect that system
* firmware didn't write it in the past few milliseconds!
*/
sr = spi_w8r8(spi, AT25_RDSR);
if (sr < 0 || sr & AT25_SR_nRDY) {
dev_dbg(&spi->dev, "rdsr --> %d (%02x)\n", sr, sr);
return -ENXIO;
}
at25 = devm_kzalloc(&spi->dev, sizeof(struct at25_data), GFP_KERNEL);
if (!at25)
return -ENOMEM;
mutex_init(&at25->lock);
at25->chip = chip;
at25->spi = spi;
spi_set_drvdata(spi, at25);
at25->addrlen = addrlen;
at25->nvmem_config.name = dev_name(&spi->dev);
at25->nvmem_config.dev = &spi->dev;
at25->nvmem_config.read_only = chip.flags & EE_READONLY;
at25->nvmem_config.root_only = true;
at25->nvmem_config.owner = THIS_MODULE;
at25->nvmem_config.compat = true;
at25->nvmem_config.base_dev = &spi->dev;
at25->nvmem_config.reg_read = at25_ee_read;
at25->nvmem_config.reg_write = at25_ee_write;
at25->nvmem_config.priv = at25;
at25->nvmem_config.stride = 4;
at25->nvmem_config.word_size = 1;
at25->nvmem_config.size = chip.byte_len;
at25->nvmem = nvmem_register(&at25->nvmem_config);
if (IS_ERR(at25->nvmem))
return PTR_ERR(at25->nvmem);
dev_info(&spi->dev, "%d %s %s eeprom%s, pagesize %u\n",
(chip.byte_len < 1024)
? chip.byte_len
: (chip.byte_len / 1024),
(chip.byte_len < 1024) ? "Byte" : "KByte",
at25->chip.name,
(chip.flags & EE_READONLY) ? " (readonly)" : "",
at25->chip.page_size);
return 0;
}
static int at25_remove(struct spi_device *spi)
{
struct at25_data *at25;
at25 = spi_get_drvdata(spi);
nvmem_unregister(at25->nvmem);
return 0;
}
/*-------------------------------------------------------------------------*/
static const struct of_device_id at25_of_match[] = {
{ .compatible = "atmel,at25", },
{ }
};
MODULE_DEVICE_TABLE(of, at25_of_match);
static struct spi_driver at25_driver = {
.driver = {
.name = "at25",
.of_match_table = at25_of_match,
},
.probe = at25_probe,
.remove = at25_remove,
};
module_spi_driver(at25_driver);
MODULE_DESCRIPTION("Driver for most SPI EEPROMs");
MODULE_AUTHOR("David Brownell");
MODULE_LICENSE("GPL");
MODULE_ALIAS("spi:at25");