[U-Boot] [RFC PATCH 08/20] mtd: nand: Add core infrastructure to deal with NAND devices

[Miquel Raynal]

Hi Jagan,

On Wed, 27 Jun 2018 16:38:26 +0530, Jagan Teki
<jagan at amarulasolutions.com> wrote:

> On Wed, Jun 6, 2018 at 9:00 PM, Miquel Raynal <miquel.raynal at bootlin.com> wrote:
> > From: Boris Brezillon <boris.brezillon at bootlin.com>
> >
> > Add an intermediate layer to abstract NAND device interface so that
> > some logic can be shared between SPI NANDs, parallel/raw NANDs,
> > OneNANDs, ...
> >
> > Signed-off-by: Boris Brezillon <boris.brezillon at bootlin.com>
> > Signed-off-by: Miquel Raynal <miquel.raynal at bootlin.com>
> > ---
> >  drivers/mtd/nand/Kconfig  |   3 +
> >  drivers/mtd/nand/Makefile |   3 +
> >  drivers/mtd/nand/bbt.c    | 132 +++++++++
> >  drivers/mtd/nand/core.c   | 243 +++++++++++++++
> >  include/linux/mtd/nand.h  | 731 ++++++++++++++++++++++++++++++++++++++++++++++
> >  5 files changed, 1112 insertions(+)
> >  create mode 100644 drivers/mtd/nand/bbt.c
> >  create mode 100644 drivers/mtd/nand/core.c
> >  create mode 100644 include/linux/mtd/nand.h
> >
> > diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig
> > index 6d53734718..1c1a1f487e 100644
> > --- a/drivers/mtd/nand/Kconfig
> > +++ b/drivers/mtd/nand/Kconfig
> > @@ -1 +1,4 @@
> > +config MTD_NAND_CORE
> > +       tristate
> > +
> >  source "drivers/mtd/nand/raw/Kconfig"
> > diff --git a/drivers/mtd/nand/Makefile b/drivers/mtd/nand/Makefile
> > index d1c3f93047..69c80ea252 100644
> > --- a/drivers/mtd/nand/Makefile
> > +++ b/drivers/mtd/nand/Makefile
> > @@ -1,3 +1,6 @@
> >  # SPDX-License-Identifier: GPL-2.0
> >
> > +nandcore-objs := core.o bbt.o
> > +obj-$(CONFIG_MTD_NAND_CORE) += nandcore.o
> > +
> >  obj-$(CONFIG_MTD_NAND) += raw/
> > diff --git a/drivers/mtd/nand/bbt.c b/drivers/mtd/nand/bbt.c
> > new file mode 100644
> > index 0000000000..7e0ad3190c
> > --- /dev/null
> > +++ b/drivers/mtd/nand/bbt.c
> > @@ -0,0 +1,132 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright (c) 2017 Free Electrons
> > + *
> > + * Authors:
> > + *     Boris Brezillon <boris.brezillon at free-electrons.com>
> > + *     Peter Pan <peterpandong at micron.com>
> > + */
> > +
> > +#define pr_fmt(fmt)    "nand-bbt: " fmt
> > +
> > +#include <linux/mtd/nand.h>
> > +#ifndef __UBOOT__
> > +#include <linux/slab.h>
> > +#endif
> > +
> > +/**
> > + * nanddev_bbt_init() - Initialize the BBT (Bad Block Table)
> > + * @nand: NAND device
> > + *
> > + * Initialize the in-memory BBT.
> > + *
> > + * Return: 0 in case of success, a negative error code otherwise.
> > + */
> > +int nanddev_bbt_init(struct nand_device *nand)
> > +{
> > +       unsigned int bits_per_block = fls(NAND_BBT_BLOCK_NUM_STATUS);
> > +       unsigned int nblocks = nanddev_neraseblocks(nand);
> > +       unsigned int nwords = DIV_ROUND_UP(nblocks * bits_per_block,
> > +                                          BITS_PER_LONG);
> > +
> > +       nand->bbt.cache = kzalloc(nwords, GFP_KERNEL);
> > +       if (!nand->bbt.cache)
> > +               return -ENOMEM;
> > +
> > +       return 0;
> > +}
> > +EXPORT_SYMBOL_GPL(nanddev_bbt_init);  
> 
> Can't we skip __UBOOT__ and EXPORT_SYMBOL_GPL ?

Do you mean that you want me to delete all the #ifndef __UBOOT__/#endif
sections?

They are present only to ease the patch backporting process from
Linux. It was very useful during the development, I don't have a
strong opinion on whether we should keep them or not, yet. 

Thanks for reviewing!
Miquèl