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

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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: Kristian Hoegsberg <krh@redhat.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de> (fixed Kconfig)
This commit is contained in:
Kristian Høgsberg 2007-05-07 20:33:31 -04:00 committed by Stefan Richter
parent 3e7cbae7c6
commit e175569c46
4 changed files with 17 additions and 27 deletions
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1
drivers/firewire/Kconfig
View file

@ -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

33
drivers/firewire/fw-card.c
View file

@ -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;
__be32 be32_block[256];
int i, length;
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;
}
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 crc;
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;

5
drivers/firewire/fw-topology.c
View file

@ -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

5
drivers/firewire/fw-topology.h
View file

@ -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 */