[coreboot] CN700 with a KVR533D2N4/512 memory module.

Urbez Santana Roma urbez at linuxupc.upc.edu
Wed Jan 16 20:59:30 CET 2008

I have the same module DRAM as more people that have written in the list
that not work with the initialization, and have tested the code of Corey
(1000 thanks Corey), and have the same results, but have found a
to the solution:

This DDR2 module works with Corey memory initialization with a little
with another values that another mainboard finds with the same DDR2
module, and 
then works, with the C7/CN700 but y not known what are the bits that
differ with
 the Corey version.

The changes for /src/northbridge/via/cn700/raminit.c (marked with a //by
another mainboard)
......chunk of sdram_enable()......
        /* (E)MRS values are from the BPG. No direct explanation is
given, but 
         * they should somehow conform to the JEDEC DDR2 SDRAM
         * (JESD79-2C). */
//      do_ram_command( RAM_COMMAND_MRS, 0x0022d8);//by Corey
        do_ram_command( RAM_COMMAND_MRS, 0x101258);//by another
//      do_ram_command( RAM_COMMAND_MRS, 0x2258);//a second mainboard
        // 7. Mode register set. 
        PRINT_DEBUG_MEM("RAM Enable 4: Mode register set\r\n");
//      do_ram_command( RAM_COMMAND_MRS, 0x21c20);//default OCD
calibration by 
        do_ram_command( RAM_COMMAND_MRS, 0x121c20);//By another
//      do_ram_command( RAM_COMMAND_MRS, 0x20020);//exit calibration
        do_ram_command( RAM_COMMAND_MRS, 0x120020);//by another
        // 8. Normal operation 
        PRINT_DEBUG_MEM("RAM Enable 5: Normal operation\r\n");
        do_ram_command( RAM_COMMAND_NORMAL, 0);
......chunk of sdram_enable()......

Only have a problem with these values. The RAM works correctly all
511MB, i can write
memory and then test it... but when i jumps
to a program loaded in memory, hangs with the first Branch instruction,
example "je". I not wise, if the C7/CN700 can have a optimization system
branches, that requires a feature with SDRAM activated. If the code
not have branches, it works. Is for me absurd....

El vie, 21-12-2007 a las 02:44 +0100, linuxbios-request at linuxbios.org
> KVR533D2N4/512,

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