[LinuxBIOS] Fwd: Re: smbus_write_byte

Joseph Smith joe at smittys.pointclark.net
Tue Aug 21 20:27:22 CEST 2007

Quoting Marc Jones <marc.jones at amd.com>:

> Joseph Smith wrote:
>>>> Joe,
>>>> There is an example of an spd array in
>>>> mainboard/artecgroup/dbe61/cache_as_ram_auto.c spd_read_byte(). You
>>>> will have to generate the correct SPD values for your memory.
>>>> Marc
>> Cool!! So let me get this straight. The function spd_read_byte() in  
>>   cache_as_ram_auto.c is re-defining the spd_read_byte() function   
>> from  src/southbridge/amd/cs5536/cs5536_early_smbus.c correct?
>> And it is saying that if the device is DIMM0 (0xA0) to read from the array?
>> So what if it is DIMM1 (0xA2)? Does it use the normal   
>> spd_read_byte()  from cs5536_early_smbus.c?
>> Thanks - Joe
> No, If it is 0xA2 it returns 0xFF as if the spd is not there.
> Marc
Oh, then I would have to switch it up a bit. This should work ok right?
static int spd_read_byte(unsigned device, unsigned address)
	int i;

	if (device == 0x50){
		return do_smbus_read_byte(device, address);
	} else if (device == 0x51){
		for (i=0; i < (sizeof spd_table/sizeof spd_table[0]); i++){
			if (spd_table[i].address == address){
				return spd_table[i].data;
	} else {
		return 0xFF; /* returns 0xFF on any failures */

Thanks - Joe

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