[PATCH] w1_ds2433: Added crc16 protection and read caching.
The changes to ds2433 to add CRC16 protection and read caching.
Signed-off-by: Ben Gardner <[email protected]>
Signed-off-by: Evgeniy Polyakov <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
commit 0a25e4d5647003a32ba5496f9d0f40ba9c1e3863
tree 678a0f192d7b72270ea3431f642baca9566a249b
parent a45f105ad4b456f99f622642056ae533f70710b7
author Evgeniy Polyakov <[email protected]> Wed, 17 Aug 2005 15:24:37 +0400
committer Greg Kroah-Hartman <[email protected]> Thu, 08 Sep 2005 14:41:27 -0700
drivers/w1/Kconfig | 9 ++++
drivers/w1/Makefile | 6 ++
drivers/w1/w1_ds2433.c | 117 ++++++++++++++++++++++++++++++++++++++++++++++--
3 files changed, 125 insertions(+), 7 deletions(-)
diff --git a/drivers/w1/Kconfig b/drivers/w1/Kconfig
--- a/drivers/w1/Kconfig
+++ b/drivers/w1/Kconfig
@@ -61,4 +61,13 @@ config W1_DS2433
Say Y here if you want to use a 1-wire
4kb EEPROM family device (DS2433).
+config W1_DS2433_CRC
+ bool "Protect DS2433 data with a CRC16"
+ depends on W1_DS2433
+ select CRC16
+ help
+ Say Y here to protect DS2433 data with a CRC16.
+ Each block has 30 bytes of data and a two byte CRC16.
+ Full block writes are only allowed if the CRC is valid.
+
endmenu
diff --git a/drivers/w1/Makefile b/drivers/w1/Makefile
--- a/drivers/w1/Makefile
+++ b/drivers/w1/Makefile
@@ -6,6 +6,10 @@ ifneq ($(CONFIG_NET), y)
EXTRA_CFLAGS += -DNETLINK_DISABLED
endif
+ifeq ($(CONFIG_W1_DS2433_CRC), y)
+EXTRA_CFLAGS += -DCONFIG_W1_F23_CRC
+endif
+
obj-$(CONFIG_W1) += wire.o
wire-objs := w1.o w1_int.o w1_family.o w1_netlink.o w1_io.o
@@ -13,7 +17,7 @@ obj-$(CONFIG_W1_MATROX) += matrox_w1.o
obj-$(CONFIG_W1_THERM) += w1_therm.o
obj-$(CONFIG_W1_SMEM) += w1_smem.o
-obj-$(CONFIG_W1_DS9490) += ds9490r.o
+obj-$(CONFIG_W1_DS9490) += ds9490r.o
ds9490r-objs := dscore.o
obj-$(CONFIG_W1_DS9490_BRIDGE) += ds_w1_bridge.o
diff --git a/drivers/w1/w1_ds2433.c b/drivers/w1/w1_ds2433.c
--- a/drivers/w1/w1_ds2433.c
+++ b/drivers/w1/w1_ds2433.c
@@ -3,9 +3,8 @@
*
* Copyright (c) 2005 Ben Gardner <[email protected]>
*
- * 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>
@@ -14,6 +13,9 @@
#include <linux/device.h>
#include <linux/types.h>
#include <linux/delay.h>
+#ifdef CONFIG_W1_F23_CRC
+#include <linux/crc16.h>
+#endif
#include "w1.h"
#include "w1_io.h"
@@ -25,18 +27,26 @@ MODULE_AUTHOR("Ben Gardner <bgardner@wab
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)
{
@@ -49,10 +59,45 @@ static inline size_t w1_f23_fix_count(lo
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;
@@ -63,6 +108,20 @@ static ssize_t w1_f23_read_bin(struct ko
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;
@@ -75,6 +134,8 @@ static ssize_t w1_f23_read_bin(struct ko
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:
@@ -85,6 +146,8 @@ 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
@@ -148,6 +211,23 @@ static ssize_t w1_f23_write_bin(struct k
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=%d\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;
@@ -190,11 +270,36 @@ static struct bin_attribute w1_f23_bin_a
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);
}
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
| |
 |