Re: staging: r8188eu: struct rt_firmware_header issues

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On 4/13/22 14:42, Michael Straube wrote:
On 4/13/22 18:27, Michael Straube wrote:
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



Ok, I figured it out by looking at the hexdumps of firmware files. The
field Rsvd1 should be u8 instead of u16. I'll prepare a patch for this.

I agree. I had prepared an analysis, but did not get it mailed before I got this one.

Larry





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