Re: [RFC 02/47] mtd: nand: add ONFI NAND Timing Mode Specifications

Jason Gunthorpe
2014-03-25T17:01:02Z

On Tue, Mar 25, 2014 at 08:19:19AM +0000, Lee Jones wrote:
> This patch adds a new structure, 'nand_timing_spec', to capture the A/C
> timing characteristics of NAND devices.

Boris BREZILLON <b.brezillon.dev@gmail.com> has been working on a
similar patch for a time now, and I think has an implementation for
the sunxi driver.

> some of the major NAND manufacturers (e.g. Samsung, Toshiba). Here we
> have followed broadly the ONFI timing definitions.

Timing specifications that are not precisely defined are
useless.. I would stick entirely with the well defined ONFI ones
until a need arises..

> + * Note, 'tR' field (maximum page read time) is extracted from the ONFI
> + * parameter page during device probe.
> + */
> +struct nand_timing_spec nand_onfi_timing_specs[] = {

const?

> + /*
> + * ONFI Timing Mode '0' (supported on all ONFI compliant devices)
> + */
> + [0] = {
> + .tCLS = 50,
> + .tCS = 70,
> + .tALS = 50,

Use picoseconds, ns is already loosing precision at the higher timing
modes.

Cheers,
Jason