staging: r8188eu: struct rt_firmware_header issues

From: Michael Straube
Date: Wed Apr 13 2022 - 12:27:36 EST


Hi all,

I think the rt_firmware_hdr structure in rtw_fw.c has some issues.


struct rt_firmware_hdr {
/* 8-byte alinment required */
/* LONG WORD 0 ---- */
__le16 Signature; /* 92C0: test chip; 92C,
* 88C0: test chip; 88C1: MP A-cut;
* 92C1: MP A-cut */
u8 Category; /* AP/NIC and USB/PCI */
u8 Function; /* Reserved for different FW function
* indcation, for further use when
* driver needs to download different
* FW for different conditions */
__le16 Version; /* FW Version */
u8 Subversion; /* FW Subversion, default 0x00 */
u16 Rsvd1;

/* LONG WORD 1 ---- */
u8 Month; /* Release time Month field */
u8 Date; /* Release time Date field */
u8 Hour; /* Release time Hour field */
u8 Minute; /* Release time Minute field */
__le16 RamCodeSize; /* The size of RAM code */
u8 Foundry;
u8 Rsvd2;

/* LONG WORD 2 ---- */
__le32 SvnIdx; /* The SVN entry index */
u32 Rsvd3;

/* LONG WORD 3 ---- */
u32 Rsvd4;
u32 Rsvd5;
};


Then we have in rtl8188e_firmware_download():


fwhdr = (struct rt_firmware_hdr *)dvobj->firmware.data;

<snip>

if (IS_FW_HEADER_EXIST(fwhdr)) {
/* Shift 32 bytes for FW header */
fw_data = fw_data + 32;
fw_size = fw_size - 32;
}

We add/sub 32 bytes but the size of struct rt_firmware_hdr is actually
33 bytes. I noticed this when I wanted to replace:

fw_data = fw_data + 32;
fw_size = fw_size - 32;

with:
fw_data = fw_data + sizeof(struct rt_firmware_hdr);
fw_size = fw_size - sizeof(struct rt_firmware_hdr);;

To me it looks add/sub 32 is correct here but the struct is
wrong. I don't know if the firmware for this driver is so much different
from firmware for the drivers in drivers/net/wireless/realtek/rtlwifi.
They use a struct of size 32.

Also, souldn't the u16 and u32 variables in the struct be __le16 and
__le32 ?

I wonder if we can just use the rtlwifi_firmware_header structure from
drivers/net/wireless/realtek/rtlwifi/wifi.h ?

Comments from people with better knowledge appreciated. :)

regards,
Michael