From: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
To: linux-kernel@vger.kernel.org
Cc: netdev@vger.kernel.org, linux-wireless@vger.kernel.org,
davem@davemloft.net, Stephen Rothwell <sfr@canb.auug.org.au>,
Sergey Lapin <slapin@ossfans.org>,
Darren Salt <linux@youmustbejoking.demon.co.uk>
Subject: [PATCH 1/6] crc-itu-t: add bit-reversed calculation
Date: Wed, 3 Jun 2009 13:33:44 +0400 [thread overview]
Message-ID: <1244021629-18409-2-git-send-email-dbaryshkov@gmail.com> (raw)
In-Reply-To: <1244021629-18409-1-git-send-email-dbaryshkov@gmail.com>
From: Darren Salt <linux@youmustbejoking.demon.co.uk>
Signed-off-by: Darren Salt <linux@youmustbejoking.demon.co.uk>
---
include/linux/crc-itu-t.h | 10 ++++++++++
lib/crc-itu-t.c | 18 ++++++++++++++++++
2 files changed, 28 insertions(+), 0 deletions(-)
diff --git a/include/linux/crc-itu-t.h b/include/linux/crc-itu-t.h
index 84920f3..7b2b7ba 100644
--- a/include/linux/crc-itu-t.h
+++ b/include/linux/crc-itu-t.h
@@ -6,6 +6,9 @@
* Poly 0x0x1021 (x^16 + x^12 + x^15 + 1)
* Init 0
*
+ * The bit-reversed buffer variants may be non-standard, but some firmware
+ * loaders require them.
+ *
* This source code is licensed under the GNU General Public License,
* Version 2. See the file COPYING for more details.
*/
@@ -14,15 +17,22 @@
#define CRC_ITU_T_H
#include <linux/types.h>
+#include <linux/bitrev.h>
extern u16 const crc_itu_t_table[256];
extern u16 crc_itu_t(u16 crc, const u8 *buffer, size_t len);
+extern u16 crc_itu_t_bitreversed(u16 crc, const u8 *buffer, size_t len);
static inline u16 crc_itu_t_byte(u16 crc, const u8 data)
{
return (crc << 8) ^ crc_itu_t_table[((crc >> 8) ^ data) & 0xff];
}
+static inline u16 crc_itu_t_bitreversed_byte(u16 crc, const u8 data)
+{
+ return (crc << 8) ^ crc_itu_t_table[((crc >> 8) ^ bitrev8(data)) & 0xff];
+}
+
#endif /* CRC_ITU_T_H */
diff --git a/lib/crc-itu-t.c b/lib/crc-itu-t.c
index a63472b..5562fdd 100644
--- a/lib/crc-itu-t.c
+++ b/lib/crc-itu-t.c
@@ -64,6 +64,24 @@ u16 crc_itu_t(u16 crc, const u8 *buffer, size_t len)
}
EXPORT_SYMBOL(crc_itu_t);
+/**
+ * crc_itu_t_bitreversed - Compute the CRC-ITU-T for the data buffer;
+ * the buffer content is assumed to be bit-reversed
+ *
+ * @crc: previous CRC value
+ * @buffer: data pointer
+ * @len: number of bytes in the buffer
+ *
+ * Returns the updated CRC value
+ */
+u16 crc_itu_t_bitreversed(u16 crc, const u8 *buffer, size_t len)
+{
+ while (len--)
+ crc = crc_itu_t_bitreversed_byte(crc, *buffer++);
+ return crc;
+}
+EXPORT_SYMBOL(crc_itu_t_bitreversed);
+
MODULE_DESCRIPTION("CRC ITU-T V.41 calculations");
MODULE_LICENSE("GPL");
--
1.6.3.1
next prev parent reply other threads:[~2009-06-03 9:34 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-03 9:33 [MERGE REQUEST] IEEE 802.15.4 stack: generic parts Dmitry Eremin-Solenikov
2009-06-03 9:33 ` Dmitry Eremin-Solenikov [this message]
2009-06-03 9:33 ` [PATCH 2/6] Add constants for the ieee 802.15.4/ZigBee stack Dmitry Eremin-Solenikov
2009-06-03 9:33 ` [PATCH 3/6] net: add IEEE 802.15.4 socket family implementation Dmitry Eremin-Solenikov
2009-06-03 9:33 ` [PATCH 4/6] net: add NL802154 interface for configuration of 802.15.4 devices Dmitry Eremin-Solenikov
2009-06-03 9:33 ` [PATCH 5/6] ieee802154: add documentation about our stack Dmitry Eremin-Solenikov
2009-06-03 9:33 ` [PATCH 6/6] ieee802154: add simple HardMAC driver sample Dmitry Eremin-Solenikov
2009-06-03 9:39 ` [PATCH 4/6] net: add NL802154 interface for configuration of 802.15.4 devices Johannes Berg
2009-06-03 10:09 ` David Miller
2009-06-03 10:52 ` Dmitry Eremin-Solenikov
2009-06-03 11:05 ` Johannes Berg
2009-06-03 12:27 ` Dmitry Eremin-Solenikov
2009-06-04 14:12 ` Johannes Berg
2009-06-04 14:51 ` Dmitry Eremin-Solenikov
2009-06-04 15:12 ` Patrick McHardy
2009-06-04 15:14 ` Dmitry Eremin-Solenikov
2009-06-04 15:15 ` Patrick McHardy
2009-06-03 12:55 ` Sergey Lapin
2009-06-03 14:21 ` Patrick McHardy
2009-06-03 23:12 ` Dmitry Eremin-Solenikov
2009-06-03 10:08 ` [PATCH 2/6] Add constants for the ieee 802.15.4/ZigBee stack David Miller
2009-06-03 10:51 ` Dmitry Eremin-Solenikov
2009-06-03 21:19 ` David Miller
2009-06-03 23:15 ` Dmitry Eremin-Solenikov
2009-06-04 0:49 ` David Miller
2009-06-03 12:43 ` [PATCH 1/6] crc-itu-t: add bit-reversed calculation Ben Hutchings
2009-06-03 12:48 ` Dmitry Eremin-Solenikov
2009-06-04 0:49 ` Dmitry Eremin-Solenikov
2009-06-21 8:29 ` Dmitry Eremin-Solenikov
2009-06-21 10:18 ` Ivo van Doorn
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