*
* Copyright (c) 2005 Ben Gardner <bgardner@wabtec.com>
*
- * This program is free software; you can redistribute it and/or modify
- * it under the smems of the GNU General Public License as published by
- * the Free Software Foundation; version 2 of the License.
+ * This source code is licensed under the GNU General Public License,
+ * Version 2. See the file COPYING for more details.
*/
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/types.h>
#include <linux/delay.h>
+#ifdef CONFIG_W1_F23_CRC
+#include <linux/crc16.h>
+
+#define CRC16_INIT 0
+#define CRC16_VALID 0xb001
+
+#endif
#include "w1.h"
#include "w1_io.h"
MODULE_DESCRIPTION("w1 family 23 driver for DS2433, 4kb EEPROM");
#define W1_EEPROM_SIZE 512
+#define W1_PAGE_COUNT 16
#define W1_PAGE_SIZE 32
#define W1_PAGE_BITS 5
#define W1_PAGE_MASK 0x1F
+#define W1_F23_TIME 300
+
#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 w1_f23_data {
+ u8 memory[W1_EEPROM_SIZE];
+ u32 validcrc;
+};
+
/**
* Check the file size bounds and adjusts count as needed.
- * This may not be needed if the sysfs layer checks bounds.
+ * 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)
{
return count;
}
-static ssize_t w1_f23_read_bin(struct kobject *kobj, char *buf, loff_t off, size_t count)
+#ifdef CONFIG_W1_F23_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 (data->validcrc & (1 << block))
+ return 0;
+
+ if (w1_reset_select_slave(sl)) {
+ data->validcrc = 0;
+ 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)
+ data->validcrc |= (1 << block);
+
+ return 0;
+}
+#endif /* CONFIG_W1_F23_CRC */
+
+static ssize_t w1_f23_read_bin(struct kobject *kobj, char *buf, loff_t off,
+ size_t count)
{
struct w1_slave *sl = kobj_to_w1_slave(kobj);
+#ifdef CONFIG_W1_F23_CRC
+ struct w1_f23_data *data = sl->family_data;
+ int i, min_page, max_page;
+#else
u8 wrbuf[3];
+#endif
if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
return 0;
goto out_dec;
}
+#ifdef CONFIG_W1_F23_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_F23_CRC */
+
/* read directly from the EEPROM */
if (w1_reset_select_slave(sl)) {
count = -EIO;
w1_write_block(sl->master, wrbuf, 3);
w1_read_block(sl->master, buf, count);
+#endif /* CONFIG_W1_F23_CRC */
+
out_up:
up(&sl->master->mutex);
out_dec:
/**
* Writes to the scratchpad and reads it back for verification.
+ * Then copies the scratchpad to EEPROM.
+ * The data must be on one page.
* The master must be locked.
*
* @param sl The slave structure
if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
return 0;
+#ifdef CONFIG_W1_F23_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_F23_CRC */
+
atomic_inc(&sl->refcnt);
if (down_interruptible(&sl->master->mutex)) {
count = 0;
static int w1_f23_add_slave(struct w1_slave *sl)
{
- return sysfs_create_bin_file(&sl->dev.kobj, &w1_f23_bin_attr);
+ int err;
+#ifdef CONFIG_W1_F23_CRC
+ struct w1_f23_data *data;
+
+ data = kmalloc(sizeof(struct w1_f23_data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+ memset(data, 0, sizeof(struct w1_f23_data));
+ sl->family_data = data;
+
+#endif /* CONFIG_W1_F23_CRC */
+
+ err = sysfs_create_bin_file(&sl->dev.kobj, &w1_f23_bin_attr);
+
+#ifdef CONFIG_W1_F23_CRC
+ if (err)
+ kfree(data);
+#endif /* CONFIG_W1_F23_CRC */
+
+ return err;
}
static void w1_f23_remove_slave(struct w1_slave *sl)
{
+#ifdef CONFIG_W1_F23_CRC
+ if (sl->family_data) {
+ kfree(sl->family_data);
+ sl->family_data = NULL;
+ }
+#endif /* CONFIG_W1_F23_CRC */
sysfs_remove_bin_file(&sl->dev.kobj, &w1_f23_bin_attr);
}
git.openpandora.org / pandora-kernel.git / blobdiff