mtd: rawnand: gpmi: Fix the driver only sense CS0 R/B issue

Set the GPMI CTRL1 GANGED_RDYBUSY bit so driver can sense the R/B signal
from all CS.

For the NAND chip MT29F64G08AFAAAWP, only the first chip detected
without the patch.

[ 3.764118] nand: device found, Manufacturer ID: 0x2c, Chip ID: 0x68
[ 3.770613] nand: Micron MT29F64G08AFAAAWP
[ 3.774752] nand: 4096 MiB, SLC, erase size: 1024 KiB, page size: 8192, OOB size: 448
[ 3.786421] Bad block table found at page 524160, version 0x01
[ 3.792730] Bad block table found at page 524032, version 0x01

After applying the patch

[ 3.764445] nand: device found, Manufacturer ID: 0x2c, Chip ID: 0x68
[ 3.770941] nand: Micron MT29F64G08AFAAAWP
[ 3.775080] nand: 4096 MiB, SLC, erase size: 1024 KiB, page size: 8192, OOB size: 448
[ 3.784390] nand: 2 chips detected
[ 3.790900] Bad block table found at page 524160, version 0x01
[ 3.796776] Bad block table found at page 1048448, version 0x01

Signed-off-by: Han Xu <han.xu@nxp.com>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20201209035104.22679-2-han.xu@nxp.com

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 1

Based on 2 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version this program is distributed in the
hope that it will be useful but without any warranty without even
the implied warranty of merchantability or fitness for a particular
purpose see the gnu general public license for more details you
should have received a copy of the gnu general public license along
with this program if not write to the free software foundation inc
51 franklin street fifth floor boston ma 02110 1301 usa

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option [no]_[pad]_[ctrl] any later version this program is
distributed in the hope that it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details you should have received a copy of the gnu general
public license along with this program if not write to the free
software foundation inc 51 franklin street fifth floor boston ma
02110 1301 usa

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 176 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Jilayne Lovejoy <opensource@jilayne.com>
Reviewed-by: Steve Winslow <swinslow@gmail.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190519154040.652910950@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

mtd: rawnand: gpmi: use core timings instead of an empirical derivation

GPMI driver timings derivation looks very empirical and does not use
the known timings that the core wants to use with the NAND chip, by
using local defined constants that have no special meaning from the
outside world.

Simplify the way all of this is computed and use the NAND core's SDR
timings.

Integrity of the reads/writes has been checked with nandbiterrs, speed
improvements with flash_speed on a Freescale i.MX6 DualLite/Solo SABRE
Automotive Board. Measures are below, variations of less than 150kiB/s
between tests are common and then not significant. Speeds using mode 5
are the same, while speeds using mode 0 are quite improved (+40/50%
from non-optimal computation).

Forcing timings mode 0:

=======================

Before this patch:
------------------
eraseblock write speed is 2298 KiB/s
eraseblock read speed is 3636 KiB/s
page write speed is 2136 KiB/s
page read speed is 3316 KiB/s
2 page write speed is 2199 KiB/s
2 page read speed is 3468 KiB/s

After this patch:
-----------------
eraseblock write speed is 3232 KiB/s
eraseblock read speed is 5663 KiB/s
page write speed is 2915 KiB/s
page read speed is 4904 KiB/s
2 page write speed is 3084 KiB/s
2 page read speed is 5267 KiB/s

Forcing timings mode 5:
=======================

Before this patch:
------------------
eraseblock write speed is 4338 KiB/s
eraseblock read speed is 14883 KiB/s
page write speed is 3786 KiB/s
page read speed is 12800 KiB/s
2 page write speed is 4076 KiB/s
2 page read speed is 14065 KiB/s

After this patch:
-----------------
eraseblock write speed is 4309 KiB/s
eraseblock read speed is 14712 KiB/s
page write speed is 3764 KiB/s
page read speed is 12673 KiB/s
2 page write speed is 4076 KiB/s
2 page read speed is 14065 KiB/s

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>

mtd: nand: move raw NAND related code to the raw/ subdir

As part of the process of sharing more code between different NAND
based devices, we need to move all raw NAND related code to the raw/
subdirectory.

Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>