[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 <bgardner@wabtec.com> Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>hifive-unleashed-5.1
Evgeniy Polyakov
Greg Kroah-Hartman
parent
a45f105ad4
commit
0a25e4d564
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@ -61,4 +61,13 @@ config W1_DS2433
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Say Y here if you want to use a 1-wire
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4kb EEPROM family device (DS2433).
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config W1_DS2433_CRC
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bool "Protect DS2433 data with a CRC16"
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depends on W1_DS2433
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select CRC16
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help
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Say Y here to protect DS2433 data with a CRC16.
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Each block has 30 bytes of data and a two byte CRC16.
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Full block writes are only allowed if the CRC is valid.
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endmenu
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@ -6,6 +6,10 @@ ifneq ($(CONFIG_NET), y)
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EXTRA_CFLAGS += -DNETLINK_DISABLED
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endif
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ifeq ($(CONFIG_W1_DS2433_CRC), y)
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EXTRA_CFLAGS += -DCONFIG_W1_F23_CRC
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endif
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obj-$(CONFIG_W1) += wire.o
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wire-objs := w1.o w1_int.o w1_family.o w1_netlink.o w1_io.o
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@ -13,7 +17,7 @@ obj-$(CONFIG_W1_MATROX) += matrox_w1.o
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obj-$(CONFIG_W1_THERM) += w1_therm.o
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obj-$(CONFIG_W1_SMEM) += w1_smem.o
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obj-$(CONFIG_W1_DS9490) += ds9490r.o
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obj-$(CONFIG_W1_DS9490) += ds9490r.o
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ds9490r-objs := dscore.o
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obj-$(CONFIG_W1_DS9490_BRIDGE) += ds_w1_bridge.o
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@ -3,9 +3,8 @@
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*
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* Copyright (c) 2005 Ben Gardner <bgardner@wabtec.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the smems of the GNU General Public License as published by
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* the Free Software Foundation; version 2 of the License.
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* This source code is licensed under the GNU General Public License,
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* Version 2. See the file COPYING for more details.
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*/
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#include <linux/kernel.h>
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@ -14,6 +13,9 @@
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#include <linux/device.h>
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#include <linux/types.h>
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#include <linux/delay.h>
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#ifdef CONFIG_W1_F23_CRC
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#include <linux/crc16.h>
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#endif
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#include "w1.h"
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#include "w1_io.h"
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@ -25,18 +27,26 @@ MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
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MODULE_DESCRIPTION("w1 family 23 driver for DS2433, 4kb EEPROM");
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#define W1_EEPROM_SIZE 512
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#define W1_PAGE_COUNT 16
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#define W1_PAGE_SIZE 32
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#define W1_PAGE_BITS 5
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#define W1_PAGE_MASK 0x1F
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#define W1_F23_TIME 300
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#define W1_F23_READ_EEPROM 0xF0
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#define W1_F23_WRITE_SCRATCH 0x0F
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#define W1_F23_READ_SCRATCH 0xAA
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#define W1_F23_COPY_SCRATCH 0x55
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struct w1_f23_data {
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u8 memory[W1_EEPROM_SIZE];
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u32 validcrc;
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};
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/**
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* Check the file size bounds and adjusts count as needed.
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* This may not be needed if the sysfs layer checks bounds.
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* This would not be needed if the file size didn't reset to 0 after a write.
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*/
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static inline size_t w1_f23_fix_count(loff_t off, size_t count, size_t size)
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{
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@ -49,10 +59,45 @@ static inline size_t w1_f23_fix_count(loff_t off, size_t count, size_t size)
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return count;
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}
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static ssize_t w1_f23_read_bin(struct kobject *kobj, char *buf, loff_t off, size_t count)
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#ifdef CONFIG_W1_F23_CRC
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static int w1_f23_refresh_block(struct w1_slave *sl, struct w1_f23_data *data,
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int block)
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{
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u8 wrbuf[3];
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int off = block * W1_PAGE_SIZE;
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if (data->validcrc & (1 << block))
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return 0;
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if (w1_reset_select_slave(sl)) {
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data->validcrc = 0;
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return -EIO;
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}
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wrbuf[0] = W1_F23_READ_EEPROM;
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wrbuf[1] = off & 0xff;
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wrbuf[2] = off >> 8;
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w1_write_block(sl->master, wrbuf, 3);
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w1_read_block(sl->master, &data->memory[off], W1_PAGE_SIZE);
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/* cache the block if the CRC is valid */
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if (crc16(CRC16_INIT, &data->memory[off], W1_PAGE_SIZE) == CRC16_VALID)
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data->validcrc |= (1 << block);
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return 0;
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}
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#endif /* CONFIG_W1_F23_CRC */
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static ssize_t w1_f23_read_bin(struct kobject *kobj, char *buf, loff_t off,
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size_t count)
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{
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struct w1_slave *sl = kobj_to_w1_slave(kobj);
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#ifdef CONFIG_W1_F23_CRC
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struct w1_f23_data *data = sl->family_data;
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int i, min_page, max_page;
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#else
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u8 wrbuf[3];
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#endif
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if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
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return 0;
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@ -63,6 +108,20 @@ static ssize_t w1_f23_read_bin(struct kobject *kobj, char *buf, loff_t off, size
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goto out_dec;
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}
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#ifdef CONFIG_W1_F23_CRC
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min_page = (off >> W1_PAGE_BITS);
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max_page = (off + count - 1) >> W1_PAGE_BITS;
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for (i = min_page; i <= max_page; i++) {
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if (w1_f23_refresh_block(sl, data, i)) {
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count = -EIO;
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goto out_up;
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}
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}
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memcpy(buf, &data->memory[off], count);
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#else /* CONFIG_W1_F23_CRC */
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/* read directly from the EEPROM */
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if (w1_reset_select_slave(sl)) {
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count = -EIO;
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@ -75,6 +134,8 @@ static ssize_t w1_f23_read_bin(struct kobject *kobj, char *buf, loff_t off, size
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w1_write_block(sl->master, wrbuf, 3);
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w1_read_block(sl->master, buf, count);
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#endif /* CONFIG_W1_F23_CRC */
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out_up:
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up(&sl->master->mutex);
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out_dec:
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@ -85,6 +146,8 @@ out_dec:
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/**
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* Writes to the scratchpad and reads it back for verification.
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* Then copies the scratchpad to EEPROM.
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* The data must be on one page.
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* The master must be locked.
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*
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* @param sl The slave structure
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@ -148,6 +211,23 @@ static ssize_t w1_f23_write_bin(struct kobject *kobj, char *buf, loff_t off,
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if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
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return 0;
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#ifdef CONFIG_W1_F23_CRC
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/* can only write full blocks in cached mode */
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if ((off & W1_PAGE_MASK) || (count & W1_PAGE_MASK)) {
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dev_err(&sl->dev, "invalid offset/count off=%d cnt=%d\n",
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(int)off, count);
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return -EINVAL;
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}
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/* make sure the block CRCs are valid */
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for (idx = 0; idx < count; idx += W1_PAGE_SIZE) {
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if (crc16(CRC16_INIT, &buf[idx], W1_PAGE_SIZE) != CRC16_VALID) {
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dev_err(&sl->dev, "bad CRC at offset %d\n", (int)off);
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return -EINVAL;
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}
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}
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#endif /* CONFIG_W1_F23_CRC */
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atomic_inc(&sl->refcnt);
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if (down_interruptible(&sl->master->mutex)) {
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count = 0;
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@ -190,11 +270,36 @@ static struct bin_attribute w1_f23_bin_attr = {
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static int w1_f23_add_slave(struct w1_slave *sl)
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{
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return sysfs_create_bin_file(&sl->dev.kobj, &w1_f23_bin_attr);
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int err;
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#ifdef CONFIG_W1_F23_CRC
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struct w1_f23_data *data;
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data = kmalloc(sizeof(struct w1_f23_data), GFP_KERNEL);
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if (!data)
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return -ENOMEM;
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memset(data, 0, sizeof(struct w1_f23_data));
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sl->family_data = data;
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#endif /* CONFIG_W1_F23_CRC */
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err = sysfs_create_bin_file(&sl->dev.kobj, &w1_f23_bin_attr);
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#ifdef CONFIG_W1_F23_CRC
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if (err)
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kfree(data);
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#endif /* CONFIG_W1_F23_CRC */
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return err;
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}
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static void w1_f23_remove_slave(struct w1_slave *sl)
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{
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#ifdef CONFIG_W1_F23_CRC
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if (sl->family_data) {
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kfree(sl->family_data);
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sl->family_data = NULL;
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}
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#endif /* CONFIG_W1_F23_CRC */
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sysfs_remove_bin_file(&sl->dev.kobj, &w1_f23_bin_attr);
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}
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