Hi Cédric,
Thanks for the patches. Indeed, 4BA is a feature that we've been looking at for a while. I'll look forward to reviewing these patches in detail.

There are a few cases that need to be considered:
- Chips which have a command to switch to 4BA mode
- Chips which have a parallel instruction set for use with 4BA.
- Chips that exclusively use 4BA commands.

I tried to cover the first two cases in my patch: https://chromium-review.googlesource.com/#/c/323359/
The third case was brought to our attention by Tim Chick: http://patchwork.coreboot.org/patch/4437/

Hopefully we can come up with a good solution for all cases.

On Sat, Jun 11, 2016 at 9:28 AM, Cédric Le Goater <clg@kaod.org> wrote:

Here's an old patchset proposed a while ago by Boris Baykov to add
4byte support to flashrom. I have been using it to flash N25Q256
modules from a raspberry pi quite successfully. Could we restart a
review cycle to see what needs fixing ?

A port of the complete patchset on 0.9.9 is available here :




Boris Baykov (6):
  4BA: Basic support for 4-bytes addressing mode extensions
  4BA: Flashrom integration for the 4-bytes addressing extensions
  4BA: Winbond W25Q256.V chip (32MB) declaration, 4-bytes addr mode
  4BA: Support for 4-bytes addressing via Extended Address Register
  4BA: Support for new direct-4BA instructions + W25Q256.V update
  4BA: Progress visualization for long read, writes and erases

 Makefile      |   2 +-
 chipdrivers.h |  22 ++
 cli_output.c  |   3 +-
 flash.h       |  21 ++
 flashchips.c  |  48 +++
 flashrom.c    |  61 ++++
 serprog.c     |   5 +-
 spi.c         |   5 +-
 spi25.c       |  37 ++-
 spi4ba.c      | 920 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 spi4ba.h      | 114 ++++++++
 11 files changed, 1231 insertions(+), 7 deletions(-)
 create mode 100644 spi4ba.c
 create mode 100644 spi4ba.h


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David Hendricks (dhendrix)
Systems Software Engineer, Google Inc.