Hi Robert, On Thu, 29 Oct 2015 07:32:33 +0100 Robert Jarzmik <robert.jarz...@free.fr> wrote:
> Marek Vasut <ma...@denx.de> writes: > > >> Isn't there the case of a single NAND controller with 2 identical chips, > >> each a 8 bit NAND chip, and the controller aggregating them to offer the > >> OS a single 16-bit NAND chip ? Honestly, I don't know how this can possibly work, do you have a real example of that use case. Here are a few reasons making it impossible: 1/ NAND are accessed using specific command sequences, and those commands and addresses cycles are sent on through the data bus (AFAIR only the lower 8bits of a 16bits bus are used for those command/address cycles), so even if you connect the CLE/ALE/CS/RB pins on both chips, the one connected on the MSB side of the data bus will just receive garbage during the command/address sequences, and your program/read operations won't work 2/ NAND chips can have bad blocks, so even if you were able to address 2 chips (which according to #1 is impossible), you might try to write on a bad block on the chip connected on the MSB side of the data bus. 3/ There probably are plenty of other reasons why this is not possible ;-). Best Regards, Boris -- Boris Brezillon, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
