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Commit e175569c authored by Kristian Høgsberg's avatar Kristian Høgsberg Committed by Stefan Richter
Browse files

firewire: Use lib/ implementation of CRC ITU-T. 



With the CRC ITU-T implementation available in lib/ we can use that instead.

This also fixes a bug in the topology map crc computation.

Signed-off-by: default avatarKristian Hoegsberg <krh@redhat.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de> (fixed Kconfig)
parent 3e7cbae7

drivers/firewire/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ comment "An alternative FireWire stack is available with EXPERIMENTAL=y" 
config FIREWIRE

	tristate "IEEE 1394 (FireWire) support (JUJU alternative stack, experimental)"

	depends on EXPERIMENTAL

	select CRC_ITU_T

	help

	  IEEE 1394 describes a high performance serial bus, which is also

	  known as FireWire(tm) or i.Link(tm) and is used for connecting all

drivers/firewire/fw-card.c

+12 −23
Original line number Diff line number Diff line
@@ -23,31 +23,22 @@ 
#include <linux/errno.h>

#include <linux/device.h>

#include <linux/rwsem.h>

#include <linux/crc-itu-t.h>

#include "fw-transaction.h"

#include "fw-topology.h"

#include "fw-device.h"



/* The lib/crc16.c implementation uses the standard (0x8005)

 * polynomial, but we need the ITU-T (or CCITT) polynomial (0x1021).

 * The implementation below works on an array of host-endian u32

 * words, assuming they'll be transmited msb first. */

u16

crc16_itu_t(const u32 *buffer, size_t length)

int fw_compute_block_crc(u32 *block)

{

	int shift, i;

	u32 data;

	u16 sum, crc = 0;



	for (i = 0; i < length; i++) {

		data = *buffer++;

		for (shift = 28; shift >= 0; shift -= 4 ) {

			sum = ((crc >> 12) ^ (data >> shift)) & 0xf;

			crc = (crc << 4) ^ (sum << 12) ^ (sum << 5) ^ (sum);

		}

		crc &= 0xffff;

	}

	__be32 be32_block[256];

	int i, length;



	return crc;

	length = (*block >> 16) & 0xff;

	for (i = 0; i < length; i++)

		be32_block[i] = cpu_to_be32(block[i + 1]);

	*block |= crc_itu_t(0, (u8 *) be32_block, length * 4);



	return length;

}



static DECLARE_RWSEM(card_rwsem);
@@ -126,10 +117,8 @@ generate_config_rom (struct fw_card *card, size_t *config_rom_length) 
	 * assumes that CRC length and info length are identical for

	 * the bus info block, which is always the case for this

	 * implementation. */

	for (i = 0; i < j; i += length + 1) {

		length = (config_rom[i] >> 16) & 0xff;

		config_rom[i] |= crc16_itu_t(&config_rom[i + 1], length);

	}

	for (i = 0; i < j; i += length + 1)

		length = fw_compute_block_crc(config_rom + i);



	*config_rom_length = j;

drivers/firewire/fw-topology.c

+2 −3
Original line number Diff line number Diff line
@@ -465,14 +465,13 @@ static void 
update_topology_map(struct fw_card *card, u32 *self_ids, int self_id_count)

{

	int node_count;

	u32 crc;



	card->topology_map[1]++;

	node_count = (card->root_node->node_id & 0x3f) + 1;

	card->topology_map[2] = (node_count << 16) | self_id_count;

	crc = crc16_itu_t(card->topology_map + 1, self_id_count + 2);

	card->topology_map[0] = ((self_id_count + 2) << 16) | crc;

	card->topology_map[0] = (self_id_count + 2) << 16;

	memcpy(&card->topology_map[3], self_ids, self_id_count * 4);

	fw_compute_block_crc(card->topology_map);

}



void

drivers/firewire/fw-topology.h

+3 −2
Original line number Diff line number Diff line
@@ -88,7 +88,8 @@ fw_node_put(struct fw_node *node) 
void

fw_destroy_nodes(struct fw_card *card);



u16

crc16_itu_t(const u32 *buffer, size_t length);

int

fw_compute_block_crc(u32 *block);





#endif /* __fw_topology_h */