// SPDX-License-Identifier: GPL-2.0-only
/*
* w1_ds2433.c - w1 family 23 (DS2433) & 43 (DS28EC20) eeprom driver
*
* Copyright (c) 2005 Ben Gardner <[email protected]>
* Copyright (c) 2023 Marc Ferland <[email protected]>
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/device.h>
#include <linux/types.h>
#include <linux/delay.h>
#include <linux/slab.h>
#ifdef CONFIG_W1_SLAVE_DS2433_CRC
#include <linux/crc16.h>
#define CRC16_INIT 0
#define CRC16_VALID 0xb001
#endif
#include <linux/w1.h>
#define W1_EEPROM_DS2433 0x23
#define W1_EEPROM_DS28EC20 0x43
#define W1_EEPROM_DS2433_SIZE 512
#define W1_EEPROM_DS28EC20_SIZE 2560
#define W1_PAGE_SIZE 32
#define W1_PAGE_BITS 5
#define W1_PAGE_MASK 0x1F
#define W1_VALIDCRC_MAX 96
#define W1_F23_READ_EEPROM 0xF0
#define W1_F23_WRITE_SCRATCH 0x0F
#define W1_F23_READ_SCRATCH 0xAA
#define W1_F23_COPY_SCRATCH 0x55
struct ds2433_config {
size_t eeprom_size; /* eeprom size in bytes */
unsigned int page_count; /* number of 256 bits pages */
unsigned int tprog; /* time in ms for page programming */
};
static const struct ds2433_config config_f23 = {
.eeprom_size = W1_EEPROM_DS2433_SIZE,
.page_count = 16,
.tprog = 5,
};
static const struct ds2433_config config_f43 = {
.eeprom_size = W1_EEPROM_DS28EC20_SIZE,
.page_count = 80,
.tprog = 10,
};
struct w1_f23_data {
#ifdef CONFIG_W1_SLAVE_DS2433_CRC
u8 *memory;
DECLARE_BITMAP(validcrc, W1_VALIDCRC_MAX);
#endif
const struct ds2433_config *cfg;
};
/*
* Check the file size bounds and adjusts count as needed.
* This would not be needed if the file size didn't reset to 0 after a write.
*/
static inline size_t w1_f23_fix_count(loff_t off, size_t count, size_t size)
{
if (off > size)
return 0;
if ((off + count) > size)
return (size - off);
return count;
}
#ifdef CONFIG_W1_SLAVE_DS2433_CRC
static int w1_f23_refresh_block(struct w1_slave *sl, struct w1_f23_data *data,
int block)
{
u8 wrbuf[3];
int off = block * W1_PAGE_SIZE;
if (test_bit(block, data->validcrc))
return 0;
if (w1_reset_select_slave(sl)) {
bitmap_zero(data->validcrc, data->cfg->page_count);
return -EIO;
}
wrbuf[0] = W1_F23_READ_EEPROM;
wrbuf[1] = off & 0xff;
wrbuf[2] = off >> 8;
w1_write_block(sl->master, wrbuf, 3);
w1_read_block(sl->master, &data->memory[off], W1_PAGE_SIZE);
/* cache the block if the CRC is valid */
if (crc16(CRC16_INIT, &data->memory[off], W1_PAGE_SIZE) == CRC16_VALID)
set_bit(block, data->validcrc);
return 0;
}
#endif /* CONFIG_W1_SLAVE_DS2433_CRC */
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 w1_slave *sl = kobj_to_w1_slave(kobj);
#ifdef CONFIG_W1_SLAVE_DS2433_CRC
struct w1_f23_data *data = sl->family_data;
int i, min_page, max_page;
#else
u8 wrbuf[3];
#endif
count = w1_f23_fix_count(off, count, bin_attr->size);
if (!count)
return 0;
mutex_lock(&sl->master->bus_mutex);
#ifdef CONFIG_W1_SLAVE_DS2433_CRC
min_page = (off >> W1_PAGE_BITS);
max_page = (off + count - 1) >> W1_PAGE_BITS;
for (i = min_page; i <= max_page; i++) {
if (w1_f23_refresh_block(sl, data, i)) {
count = -EIO;
goto out_up;
}
}
memcpy(buf, &data->memory[off], count);
#else /* CONFIG_W1_SLAVE_DS2433_CRC */
/* read directly from the EEPROM */
if (w1_reset_select_slave(sl)) {
count = -EIO;
goto out_up;
}
wrbuf[0] = W1_F23_READ_EEPROM;
wrbuf[1] = off & 0xff;
wrbuf[2] = off >> 8;
w1_write_block(sl->master, wrbuf, 3);
w1_read_block(sl->master, buf, count);
#endif /* CONFIG_W1_SLAVE_DS2433_CRC */
out_up:
mutex_unlock(&sl->master->bus_mutex);
return count;
}
/**
* w1_f23_write() - Writes to the scratchpad and reads it back for verification.
* @sl: The slave structure
* @addr: Address for the write
* @len: length must be <= (W1_PAGE_SIZE - (addr & W1_PAGE_MASK))
* @data: The data to write
*
* Then copies the scratchpad to EEPROM.
* The data must be on one page.
* The master must be locked.
*
* Return: 0=Success, -1=failure
*/
static int w1_f23_write(struct w1_slave *sl, int addr, int len, const u8 *data)
{
struct w1_f23_data *f23 = sl->family_data;
u8 wrbuf[4];
u8 rdbuf[W1_PAGE_SIZE + 3];
u8 es = (addr + len - 1) & 0x1f;
/* Write the data to the scratchpad */
if (w1_reset_select_slave(sl))
return -1;
wrbuf[0] = W1_F23_WRITE_SCRATCH;
wrbuf[1] = addr & 0xff;
wrbuf[2] = addr >> 8;
w1_write_block(sl->master, wrbuf, 3);
w1_write_block(sl->master, data, len);
/* Read the scratchpad and verify */
if (w1_reset_select_slave(sl))
return -1;
w1_write_8(sl->master, W1_F23_READ_SCRATCH);
w1_read_block(sl->master, rdbuf, len + 3);
/* Compare what was read against the data written */
if ((rdbuf[0] != wrbuf[1]) || (rdbuf[1] != wrbuf[2]) ||
(rdbuf[2] != es) || (memcmp(data, &rdbuf[3], len) != 0))
return -1;
/* Copy the scratchpad to EEPROM */
if (w1_reset_select_slave(sl))
return -1;
wrbuf[0] = W1_F23_COPY_SCRATCH;
wrbuf[3] = es;
w1_write_block(sl->master, wrbuf, 4);
/* Sleep for tprog ms to wait for the write to complete */
msleep(f23->cfg->tprog);
/* Reset the bus to wake up the EEPROM (this may not be needed) */
w1_reset_bus(sl->master);
#ifdef CONFIG_W1_SLAVE_DS2433_CRC
clear_bit(addr >> W1_PAGE_BITS, f23->validcrc);
#endif
return 0;
}
static ssize_t eeprom_write(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr, char *buf,
loff_t off, size_t count)
{
struct w1_slave *sl = kobj_to_w1_slave(kobj);
int addr, len, idx;
count = w1_f23_fix_count(off, count, bin_attr->size);
if (!count)
return 0;
#ifdef CONFIG_W1_SLAVE_DS2433_CRC
/* can only write full blocks in cached mode */
if ((off & W1_PAGE_MASK) || (count & W1_PAGE_MASK)) {
dev_err(&sl->dev, "invalid offset/count off=%d cnt=%zd\n",
(int)off, count);
return -EINVAL;
}
/* make sure the block CRCs are valid */
for (idx = 0; idx < count; idx += W1_PAGE_SIZE) {
if (crc16(CRC16_INIT, &buf[idx], W1_PAGE_SIZE) != CRC16_VALID) {
dev_err(&sl->dev, "bad CRC at offset %d\n", (int)off);
return -EINVAL;
}
}
#endif /* CONFIG_W1_SLAVE_DS2433_CRC */
mutex_lock(&sl->master->bus_mutex);
/* Can only write data to one page at a time */
idx = 0;
while (idx < count) {
addr = off + idx;
len = W1_PAGE_SIZE - (addr & W1_PAGE_MASK);
if (len > (count - idx))
len = count - idx;
if (w1_f23_write(sl, addr, len, &buf[idx]) < 0) {
count = -EIO;
goto out_up;
}
idx += len;
}
out_up:
mutex_unlock(&sl->master->bus_mutex);
return count;
}
static struct bin_attribute bin_attr_f23_eeprom = {
.attr = { .name = "eeprom", .mode = 0644 },
.read = eeprom_read,
.write = eeprom_write,
.size = W1_EEPROM_DS2433_SIZE,
};
static struct bin_attribute bin_attr_f43_eeprom = {
.attr = { .name = "eeprom", .mode = 0644 },
.read = eeprom_read,
.write = eeprom_write,
.size = W1_EEPROM_DS28EC20_SIZE,
};
static struct bin_attribute *w1_f23_bin_attributes[] = {
&bin_attr_f23_eeprom,
NULL,
};
static const struct attribute_group w1_f23_group = {
.bin_attrs = w1_f23_bin_attributes,
};
static const struct attribute_group *w1_f23_groups[] = {
&w1_f23_group,
NULL,
};
static struct bin_attribute *w1_f43_bin_attributes[] = {
&bin_attr_f43_eeprom,
NULL,
};
static const struct attribute_group w1_f43_group = {
.bin_attrs = w1_f43_bin_attributes,
};
static const struct attribute_group *w1_f43_groups[] = {
&w1_f43_group,
NULL,
};
static int w1_f23_add_slave(struct w1_slave *sl)
{
struct w1_f23_data *data;
data = kzalloc(sizeof(struct w1_f23_data), GFP_KERNEL);
if (!data)
return -ENOMEM;
switch (sl->family->fid) {
case W1_EEPROM_DS2433:
data->cfg = &config_f23;
break;
case W1_EEPROM_DS28EC20:
data->cfg = &config_f43;
break;
}
#ifdef CONFIG_W1_SLAVE_DS2433_CRC
if (data->cfg->page_count > W1_VALIDCRC_MAX) {
dev_err(&sl->dev, "page count too big for crc bitmap\n");
kfree(data);
return -EINVAL;
}
data->memory = kzalloc(data->cfg->eeprom_size, GFP_KERNEL);
if (!data->memory) {
kfree(data);
return -ENOMEM;
}
bitmap_zero(data->validcrc, data->cfg->page_count);
#endif /* CONFIG_W1_SLAVE_DS2433_CRC */
sl->family_data = data;
return 0;
}
static void w1_f23_remove_slave(struct w1_slave *sl)
{
struct w1_f23_data *data = sl->family_data;
sl->family_data = NULL;
#ifdef CONFIG_W1_SLAVE_DS2433_CRC
kfree(data->memory);
#endif /* CONFIG_W1_SLAVE_DS2433_CRC */
kfree(data);
}
static const struct w1_family_ops w1_f23_fops = {
.add_slave = w1_f23_add_slave,
.remove_slave = w1_f23_remove_slave,
.groups = w1_f23_groups,
};
static const struct w1_family_ops w1_f43_fops = {
.add_slave = w1_f23_add_slave,
.remove_slave = w1_f23_remove_slave,
.groups = w1_f43_groups,
};
static struct w1_family w1_family_23 = {
.fid = W1_EEPROM_DS2433,
.fops = &w1_f23_fops,
};
static struct w1_family w1_family_43 = {
.fid = W1_EEPROM_DS28EC20,
.fops = &w1_f43_fops,
};
static int __init w1_ds2433_init(void)
{
int err;
err = w1_register_family(&w1_family_23);
if (err)
return err;
err = w1_register_family(&w1_family_43);
if (err)
goto err_43;
return 0;
err_43:
w1_unregister_family(&w1_family_23);
return err;
}
static void __exit w1_ds2433_exit(void)
{
w1_unregister_family(&w1_family_23);
w1_unregister_family(&w1_family_43);
}
module_init(w1_ds2433_init);
module_exit(w1_ds2433_exit);
MODULE_AUTHOR("Ben Gardner <[email protected]>");
MODULE_AUTHOR("Marc Ferland <[email protected]>");
MODULE_DESCRIPTION("w1 family 23/43 driver for DS2433 (4kb) and DS28EC20 (20kb)");
MODULE_LICENSE("GPL");
MODULE_ALIAS("w1-family-" __stringify(W1_EEPROM_DS2433));
MODULE_ALIAS("w1-family-" __stringify(W1_EEPROM_DS28EC20));
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