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authorRonald G. Minnich <rminnich@gmail.com>2009-05-08 19:23:00 +0000
committerRonald G. Minnich <rminnich@gmail.com>2009-05-08 19:23:00 +0000
commit83b8f0c48550bb1b2cb1a6610b1f0010bf8533a4 (patch)
tree2eb1bea8b83b2062519823b7202892a124aef876 /util/cbfstool/EXAMPLE
parentaa1df9cba598ff1ddbf81d182a9f978f89daf2e8 (diff)
downloadcoreboot-83b8f0c48550bb1b2cb1a6610b1f0010bf8533a4.tar.xz
I have made a very simple mod to cbfstool that is compatible with the
src/lib/ code in coreboot. I.e. the tool changes but the coreboot code does not. Currently, as cbfstool manages the ROM, there are files and empty space. To allocate files, the code does, first, a walk of the headers and, if that fails, does a brute-force search of the rest of the space. We all agree that the brute-force search has lots of problems from a performance and correctness standpoint. I've made a slight change. Instead of an "empty space" area with no valid headers, I've made a header for the empty space. So cbfs creation looks like this: - set up the boot block - create a file, of type CBFS_COMPONENT_NULL, that contains the empty space. CBFS_COMPONENT_NULL was already defined in cbfs.h Here's an example: [rminnich@xcpu2 cbfstool]$ ./cbfstool testcbfs create 1048576 2048 (cbfstool) E: Unable to open (null): Bad address [rminnich@xcpu2 cbfstool]$ ./cbfstool testcbfs print testcbfs: 1024 kB, bootblocksize 2048, romsize 1048576, offset 0x0 Alignment: 16 bytes Name Offset Type Size 0x0 0xffffffff 1046456 So how do we create a new file? It's easy: walk the files and find a file of type CBFS_COMPONENT_NULL, which is as large or larger than the file you are trying to create. Then you use that file. - if the file is the same size as the NULL file, then it's easy: take it - if the file is smaller than the NULL file, you split the NULL file into two parts. note that this works in the base case: the base case is that the whole storage is CBFS_COMPONENT_NULL. Here's an example of adding a file. [rminnich@xcpu2 cbfstool]$ ./cbfstool testcbfs add-stage testfixed t [rminnich@xcpu2 cbfstool]$ ./cbfstool testcbfs print testcbfs: 1024 kB, bootblocksize 2048, romsize 1048576, offset 0x0 Alignment: 16 bytes Name Offset Type Size t 0x0 stage 23176 0x5ab0 0xffffffff 1023240 Note that the NULL split and got smaller. But the entire ROM is still contained by the two files. To walk this entire rom will require two FLASH accesses. Add another file: [rminnich@xcpu2 cbfstool]$ ./cbfstool testcbfs add-stage testfixed tt [rminnich@xcpu2 cbfstool]$ ./cbfstool testcbfs print testcbfs: 1024 kB, bootblocksize 2048, romsize 1048576, offset 0x0 Alignment: 16 bytes Name Offset Type Size t 0x0 stage 23176 tt 0x5ab0 stage 23176 0xb560 0xffffffff 1000024 [rminnich@xcpu2 cbfstool]$ So, taking current ROMs as an example, I can reduce FLASH accesses for cbfs from (potentially) thousands to (typically) less than 10. Index: fs.c Changes for readability and cleanliness. Move common blobs of code to functions. New function: rom_alloc,which allocates files by finding NULL files and using/splitting. Other changes as needed to support this usage. Index: util.c Creating a cbfs archive now requires creation of a NULL file covering the file system space. Index: cbfs.h Add a DELETED file type with value 0. Any file can be marked deleted by zero its type; this is a FLASH-friendly definition for all known FLASH types. Signed-off-by: Ronald G. Minnich <rminnich@gmail.com> I think it is a step in the right direction. Could you add the function prototype to cbfstool.h? Acked-by: Myles Watson <mylesgw@gmail.com> (I added the prototype) git-svn-id: svn://svn.coreboot.org/coreboot/trunk@4261 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1
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