CBFS document is a little old since the structure of it has changed a lot specially CBFS master header. This patch updated the document to show the newest structure of CBFS.
Signed-off-by: Yang Bai <[email protected]> Index: documentation/cbfs.txt =================================================================== --- documentation/cbfs.txt (revision 6534) +++ documentation/cbfs.txt (working copy) @@ -144,10 +144,13 @@ The following is the structure of the master header: struct cbfs_header { - unsigned int magic; - unsigned int size; - unsigned int align; - unsigned int offset; + u32 magic; + u32 version; + u32 romsize; + u32 bootblocksize; + u32 align; + u32 offset; + u32 pad[2]; }; The meaning of each member is as follows: @@ -156,9 +159,14 @@ magic number is 0x4F524243, which is 'ORBC' in ASCII. -'size' is the size of the ROM in bytes. Coreboot will subtract 'size' from +'version' is a 32 bit number that shows the version of CBFS master header. +Since only one version exists now, it should always be 0x31313131. + +'romsize' is the size of the ROM in bytes. Coreboot will subtract 'romsize' from 0xFFFFFFFF to locate the beginning of the ROM in memory. +'bootblocksize' is the size of the bootblock in bytes. + 'align' is the number of bytes that each component is aligned to within the ROM. This is used to make sure that each component is aligned correctly with @@ -193,11 +201,11 @@ Each CBFS component starts with a header: struct cbfs_file { - char magic[8]; - unsigned int len; - unsigned int type; - unsigned int checksum; - unsigned int offset; + char magic[8]; + u32 len; + u32 type; + u32 checksum; + u32 offset; }; 'magic' is a magic value used to identify the header. During runtime, @@ -287,11 +295,11 @@ The header is defined as: struct cbfs_stage { - unsigned int compression; - unsigned long long entry; - unsigned long long load; - unsigned int len; - unsigned int memlen; + u32 compression; /** Compression type */ + u64 entry; /** entry point */ + u64 load; /** Where to load in memory */ + u32 len; /** length of data to load */ + u32 memlen; /** total length of object in memory */ }; 'compression' is an integer defining how the data is compressed. There @@ -355,12 +363,12 @@ The following is the structure of each segment header: struct cbfs_payload_segment { - unsigned int type; - unsigned int compression; - unsigned int offset; - unsigned long long load_addr; - unsigned int len; - unsigned int mem_len; + u32 type; + u32 compression; + u32 offset; + u64 load_addr; + u32 len; + u32 mem_len; }; 'type' is the type of segment, one of the following: -- """ Keep It Simple,Stupid. """ Chinese Name: 白杨 Nick Name: Hamo Homepage: http://hamobai.com/ GPG KEY ID: 0xA4691A33 Key fingerprint = 09D5 2D78 8E2B 0995 CF8E 4331 33C4 3D24 A469 1A33 -- coreboot mailing list: [email protected] http://www.coreboot.org/mailman/listinfo/coreboot
