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authorArend van Spriel <arend@broadcom.com>2011-05-31 11:22:15 +0200
committerJohn W. Linville <linville@tuxdriver.com>2011-06-03 15:01:06 -0400
commit7150962d637cf38617924f7f72ea00612283eb89 (patch)
treeb9c336c00c32e986b73bfabc3a70c78d821659bc /lib
parentdabd3001f941e35c4afa2458ceb17e5170062189 (diff)
downloadautogen-7150962d637cf38617924f7f72ea00612283eb89.tar.gz
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lib: crc8: add new library module providing crc8 algorithm
The brcm80211 driver in staging tree uses a crc8 function. Based on feedback from John Linville to move this to lib directory, the linux source has been searched. Although there is currently only one other kernel driver using this algorithm (ie. drivers/ssb) we are providing this as a library function for others to use. Cc: linux-kernel@vger.kernel.org Cc: linux-wireless@vger.kernel.org Cc: Dan Carpenter <error27@gmail.com> Cc: George Spelvin <linux@horizon.com> Cc: Randy Dunlap <rdunlap@xenotime.net> Reviewed-by: Henry Ptasinski <henryp@broadcom.com> Reviewed-by: Roland Vossen <rvossen@broadcom.com> Reviewed-by: "Franky (Zhenhui) Lin" <frankyl@broadcom.com> Signed-off-by: Arend van Spriel <arend@broadcom.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
Diffstat (limited to 'lib')
-rw-r--r--lib/Kconfig7
-rw-r--r--lib/Makefile1
-rw-r--r--lib/crc8.c86
3 files changed, 94 insertions, 0 deletions
diff --git a/lib/Kconfig b/lib/Kconfig
index 9c10e38fc60..ff9e5a34be7 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -89,6 +89,13 @@ config LIBCRC32C
require M here. See Castagnoli93.
Module will be libcrc32c.
+config CRC8
+ tristate "CRC8 function"
+ help
+ This option provides CRC8 function. Drivers may select this
+ when they need to do cyclic redundancy check according CRC8
+ algorithm. Module will be called crc8.
+
config AUDIT_GENERIC
bool
depends on AUDIT && !AUDIT_ARCH
diff --git a/lib/Makefile b/lib/Makefile
index 4b49a249064..704959d2018 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -65,6 +65,7 @@ obj-$(CONFIG_CRC_ITU_T) += crc-itu-t.o
obj-$(CONFIG_CRC32) += crc32.o
obj-$(CONFIG_CRC7) += crc7.o
obj-$(CONFIG_LIBCRC32C) += libcrc32c.o
+obj-$(CONFIG_CRC8) += crc8.o
obj-$(CONFIG_GENERIC_ALLOCATOR) += genalloc.o
obj-$(CONFIG_ZLIB_INFLATE) += zlib_inflate/
diff --git a/lib/crc8.c b/lib/crc8.c
new file mode 100644
index 00000000000..87b59cafdb8
--- /dev/null
+++ b/lib/crc8.c
@@ -0,0 +1,86 @@
+/*
+ * Copyright (c) 2011 Broadcom Corporation
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/crc8.h>
+#include <linux/printk.h>
+
+/*
+ * crc8_populate_msb - fill crc table for given polynomial in reverse bit order.
+ *
+ * table: table to be filled.
+ * polynomial: polynomial for which table is to be filled.
+ */
+void crc8_populate_msb(u8 table[CRC8_TABLE_SIZE], u8 polynomial)
+{
+ int i, j;
+ const u8 msbit = 0x80;
+ u8 t = msbit;
+
+ table[0] = 0;
+
+ for (i = 1; i < CRC8_TABLE_SIZE; i *= 2) {
+ t = (t << 1) ^ (t & msbit ? polynomial : 0);
+ for (j = 0; j < i; j++)
+ table[i+j] = table[j] ^ t;
+ }
+}
+EXPORT_SYMBOL(crc8_populate_msb);
+
+/*
+ * crc8_populate_lsb - fill crc table for given polynomial in regular bit order.
+ *
+ * table: table to be filled.
+ * polynomial: polynomial for which table is to be filled.
+ */
+void crc8_populate_lsb(u8 table[CRC8_TABLE_SIZE], u8 polynomial)
+{
+ int i, j;
+ u8 t = 1;
+
+ table[0] = 0;
+
+ for (i = (CRC8_TABLE_SIZE >> 1); i; i >>= 1) {
+ t = (t >> 1) ^ (t & 1 ? polynomial : 0);
+ for (j = 0; j < CRC8_TABLE_SIZE; j += 2*i)
+ table[i+j] = table[j] ^ t;
+ }
+}
+EXPORT_SYMBOL(crc8_populate_lsb);
+
+/*
+ * crc8 - calculate a crc8 over the given input data.
+ *
+ * table: crc table used for calculation.
+ * pdata: pointer to data buffer.
+ * nbytes: number of bytes in data buffer.
+ * crc: previous returned crc8 value.
+ */
+u8 crc8(const u8 table[CRC8_TABLE_SIZE], u8 *pdata, size_t nbytes, u8 crc)
+{
+ /* loop over the buffer data */
+ while (nbytes-- > 0)
+ crc = table[(crc ^ *pdata++) & 0xff];
+
+ return crc;
+}
+EXPORT_SYMBOL(crc8);
+
+MODULE_DESCRIPTION("CRC8 (by Williams, Ross N.) function");
+MODULE_AUTHOR("Broadcom Corporation");
+MODULE_LICENSE("Dual BSD/GPL");