On Tue, Nov 20, 2018 at 12:32 AM <valdis.kletnieks@xxxxxx> wrote: > > On Tue, 20 Nov 2018 00:04:03 +0200, Ranran said: > > > That's interesting... > > I think the name is confusing, because this chips are also writable. > > > > Not only this, but in arm the eeprom (at24) is writable! > > But in the x86 I am using, it is readonly in kernel code: > > https://android.googlesource.com/kernel/omap/+/glass-omap-xrr02/drivers/misc/eeprom/eeprom.c > > static struct bin_attribute eeprom_attr = { > > .attr = { > > .name = "eeprom", > > .mode = S_IRUGO, > > }, > > .size = EEPROM_SIZE, > > .read = eeprom_read, > > }; > > Well, at least in the mainline kernel, we have this at the top of the eeprom.c file: > > /* Addresses to scan */ > static const unsigned short normal_i2c[] = { 0x50, 0x51, 0x52, 0x53, 0x54, > 0x55, 0x56, 0x57, I2C_CLIENT_END }; > > > /* Size of EEPROM in bytes */ > #define EEPROM_SIZE 256 > > which is pretty obviously intended for "very small eeprom hanging off an I2C adapter", > and thus probably *NOT* the boot ROM that the BIOS lives in. although I think that in my system it is a flash rom which stores the BIOS, so I really don't know what's the use of the eeprom.... I need a very small amout of data (several bytes) to save some non volatile information in x86 system. I can't use disk for this, but can use any other peripheral or even x86 chip on board. Now it also seems that I can't use the eeprom becuase of the kernel limitation (can I open it for writing if the BIOS is not stored there??) I don't have any idea where I can find such storage. Does x86 include some programmable registers ? Do you have any idea where I can store the data ? Thanks _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
