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authorMark Brown <broonie@opensource.wolfsonmicro.com>2011-08-08 14:56:19 +0900
committerMark Brown <broonie@opensource.wolfsonmicro.com>2011-08-08 14:56:19 +0900
commit18d4ed4342c14ebeebe60d267b171053efcdfa87 (patch)
treef315e77f66cbb70869e2f80cde5c18380a80901e /lib/crc8.c
parent722d0daf2b607a32dad1357bf797e3803484af0a (diff)
parent22de4534ae12d61257fc0e53d2571686b03305bc (diff)
Merge branch 'for-3.1' into for-3.2
Conflict due to the fix for the register map failure - taken the for-3.1 version. Conflicts: sound/soc/codecs/sgtl5000.c
Diffstat (limited to 'lib/crc8.c')
-rw-r--r--lib/crc8.c86
1 files changed, 86 insertions, 0 deletions
diff --git a/lib/crc8.c b/lib/crc8.c
new file mode 100644
index 000000000000..87b59cafdb83
--- /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");