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net: dlink: Correct endianness handling of led_mode

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As it's name suggests, parse_eeprom() parses EEPROM data.

This is done by reading data, 16 bits at a time as follows:

	for (i = 0; i < 128; i++)
                ((__le16 *) sromdata)[i] = cpu_to_le16(read_eeprom(np, i));

sromdata is at the same memory location as psrom.
And the type of psrom is a pointer to struct t_SROM.

As can be seen in the loop above, data is stored in sromdata, and thus psrom,
as 16-bit little-endian values.

However, the integer fields of t_SROM are host byte order integers.
And in the case of led_mode this leads to a little endian value
being incorrectly treated as host byte order.

Looking at rio_set_led_mode, this does appear to be a bug as that code
masks led_mode with 0x1, 0x2 and 0x8. Logic that would be effected by a
reversed byte order.

This problem would only manifest on big endian hosts.

Found by inspection while investigating a sparse warning
regarding the crc field of t_SROM.

I believe that warning is a false positive. And although I plan
to send a follow-up to use little-endian types for other the integer
fields of PSROM_t I do not believe that will involve any bug fixes.

Compile tested only.

Fixes: c3f45d322c ("dl2k: Add support for IP1000A-based cards")
Signed-off-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250425-dlink-led-mode-v1-1-6bae3c36e736@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Simon Horman 2025-04-25 16:50:47 +01:00 • committed by Jakub Kicinski
parent d4cb1ecc22
commit e7e5ae7183
2 changed files with 2 additions and 2 deletions
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2
drivers/net/ethernet/dlink/dl2k.c
View file

@ -352,7 +352,7 @@ parse_eeprom (struct net_device *dev)
eth_hw_addr_set(dev, psrom->mac_addr);
if (np->chip_id == CHIP_IP1000A) {
np->led_mode = psrom->led_mode;
np->led_mode = le16_to_cpu(psrom->led_mode);
return 0;
}

2
drivers/net/ethernet/dlink/dl2k.h
View file

@ -335,7 +335,7 @@ typedef struct t_SROM {
u16 sub_system_id; /* 0x06 */
u16 pci_base_1; /* 0x08 (IP1000A only) */
u16 pci_base_2; /* 0x0a (IP1000A only) */
u16 led_mode; /* 0x0c (IP1000A only) */
__le16 led_mode; /* 0x0c (IP1000A only) */
u16 reserved1[9]; /* 0x0e-0x1f */
u8 mac_addr[6]; /* 0x20-0x25 */
u8 reserved2[10]; /* 0x26-0x2f */