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qed: Reimplement qed_mcast_bin_from_mac() using library functions 

The calculation done by qed_calc_crc32c() is the standard
least-significant-bit-first CRC-32C except it uses
most-significant-bit-first order for the actual CRC variable.  That is
equivalent to bit-reflecting the input and output CRC.  Replace it with
equivalent calls to the corresponding library functions.

Tested with a simple userspace program which tested that the old and new
implementations of qed_mcast_bin_from_mac() produce the same outputs.

Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Link: https://patch.msgid.link/20260316221453.66078-1-ebiggers@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
master
Eric Biggers 2026-03-16 15:14:53 -07:00 committed by Jakub Kicinski
parent 4455a30b04
commit d5516452a3
1 changed files with 11 additions and 42 deletions
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53
drivers/net/ethernet/qlogic/qed/qed_l2.c
View File

@ -7,6 +7,7 @@
#include <linux/types.h>
#include <asm/byteorder.h>
#include <asm/param.h>
#include <linux/crc32.h>
#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <linux/etherdevice.h>
@ -39,7 +40,6 @@
#include "qed_sriov.h"
#define QED_MAX_SGES_NUM 16
#define CRC32_POLY 0x1edc6f41
struct qed_l2_info {
u32 queues;
@ -1412,50 +1412,19 @@ int qed_sp_eth_filter_ucast(struct qed_hwfn *p_hwfn,
return 0;
}
/*******************************************************************************
* Description:
* Calculates crc 32 on a buffer
* Note: crc32_length MUST be aligned to 8
* Return:
******************************************************************************/
static u32 qed_calc_crc32c(u8 *crc32_packet,
u32 crc32_length, u32 crc32_seed, u8 complement)
{
u32 byte = 0, bit = 0, crc32_result = crc32_seed;
u8 msb = 0, current_byte = 0;
if ((!crc32_packet) ||
(crc32_length == 0) ||
((crc32_length % 8) != 0))
return crc32_result;
for (byte = 0; byte < crc32_length; byte++) {
current_byte = crc32_packet[byte];
for (bit = 0; bit < 8; bit++) {
msb = (u8)(crc32_result >> 31);
crc32_result = crc32_result << 1;
if (msb != (0x1 & (current_byte >> bit))) {
crc32_result = crc32_result ^ CRC32_POLY;
crc32_result |= 1; /*crc32_result[0] = 1;*/
}
}
}
return crc32_result;
}
static u32 qed_crc32c_le(u32 seed, u8 *mac, u32 len)
{
u32 packet_buf[2] = { 0 };
memcpy((u8 *)(&packet_buf[0]), &mac[0], 6);
return qed_calc_crc32c((u8 *)packet_buf, 8, seed, 0);
}
u8 qed_mcast_bin_from_mac(u8 *mac)
{
u32 crc = qed_crc32c_le(ETH_MULTICAST_BIN_FROM_MAC_SEED,
mac, ETH_ALEN);
u8 padded_mac[8] = {};
u32 crc;
return crc & 0xff;
memcpy(padded_mac, mac, ETH_ALEN);
/*
* This uses the standard CRC-32C, but with the input and output CRCs
* bit-reflected and the bit-reflected output CRC truncated to 8 bits.
*/
crc = crc32c(bitrev32(ETH_MULTICAST_BIN_FROM_MAC_SEED), padded_mac,
sizeof(padded_mac));
return bitrev8(crc >> 24);
}
static int