NAND driver
Mark Underwood
basicmark at yahoo.com
Tue Feb 26 04:04:27 EST 2008
--- Mark Underwood <basicmark at yahoo.com> wrote:
> Im writing a NAND driver for an ASIC. The NAND controller has been designed to handle page read
> &
> writes with little SW intervention using interrupts or DMA, so I plan to implement the
> write_page_raw & read_page_raw functions.
> However, looking through nand_base.c it looks like not all NAND access go through these
> functions
> so to start with I have implemented the cmd_ctrl function & supplied the IO_ADDR_R & IO_ADDR_W
> address with the thinking that these would be a fall back when the access doesn't go through the
> raw functions.
> Unfortunately it seems the single write functionality of the controller is broken. The page
> read
> & write functionality only allow me to work in 512byte blocks so I can't write OOB that way. Can
> you confirm that there are cases where OOB is written separately and if so do you have any
> suggestions for getting around this problem?
>
> Many thanks,
>
> Mark
>
I forgot to say that I'm working on a 2.6.21.1 kernel.
After some pondering I managed to implement the single write functionality by abusing the command
fifo and playing with GPIO pins.
Looking through nand_base.c I notice that although I can pass in *_page_raw operations in the
nand_chip structure they are not used in the *_page_swecc functions but instead they call the
internal *_page_raw functions directly. I propose just to replace the direct calls with indirect
ones (via the function pointers in the nand_chip structure). Does this proposal sound OK?
Mark
>
>
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