[U-Boot] [RFC PATCH 10/20] spi: Extend the core to ease integration of SPI memory controllers

[Jagan Teki <jagannadh.teki@gmail.com>]

On Wed, Jul 11, 2018 at 7:25 PM, Miquel Raynal
<miquel.raynal@bootlin.com> wrote:
> Hi Jagan,
>
> Jagan Teki <jagannadh.teki@gmail.com> wrote on Fri, 6 Jul 2018 17:02:22
> +0530:
>
>> On Wed, Jun 6, 2018 at 9:00 PM, Miquel Raynal <miquel.raynal@bootlin.com> wrote:
>> > From: Boris Brezillon <boris.brezillon@bootlin.com>
>> >
>> > Some controllers are exposing high-level interfaces to access various
>> > kind of SPI memories. Unfortunately they do not fit in the current
>> > spi_controller model and usually have drivers placed in
>> > drivers/mtd/spi-nor which are only supporting SPI NORs and not SPI
>> > memories in general.
>> >
>> > This is an attempt at defining a SPI memory interface which works for
>> > all kinds of SPI memories (NORs, NANDs, SRAMs).
>> >
>> > Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
>> > Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
>> > ---
>> >  drivers/spi/Kconfig   |   7 +
>> >  drivers/spi/Makefile  |   1 +
>> >  drivers/spi/spi-mem.c | 500 ++++++++++++++++++++++++++++++++++++++++++++++++++
>> >  include/spi-mem.h     | 258 ++++++++++++++++++++++++++
>> >  include/spi.h         |  11 ++
>> >  5 files changed, 777 insertions(+)
>> >  create mode 100644 drivers/spi/spi-mem.c
>> >  create mode 100644 include/spi-mem.h
>> >
>> > diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
>> > index 235a8c7d73..0ee371b2d9 100644
>> > --- a/drivers/spi/Kconfig
>> > +++ b/drivers/spi/Kconfig
>> > @@ -15,6 +15,13 @@ config DM_SPI
>> >
>> >  if DM_SPI
>> >
>> > +config SPI_MEM
>> > +       bool "SPI memory extension"
>> > +       help
>> > +         Enable this option if you want to enable the SPI memory extension.
>> > +         This extension is meant to simplify interaction with SPI memories
>> > +         by providing an high-level interface to send memory-like commands.
>> > +
>> >  config ALTERA_SPI
>> >         bool "Altera SPI driver"
>> >         help
>> > diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
>> > index 4b6000fd9a..982529a0e6 100644
>> > --- a/drivers/spi/Makefile
>> > +++ b/drivers/spi/Makefile
>> > @@ -10,6 +10,7 @@ ifdef CONFIG_DM_SPI
>> >  obj-y += spi-uclass.o
>> >  obj-$(CONFIG_SANDBOX) += spi-emul-uclass.o
>> >  obj-$(CONFIG_SOFT_SPI) += soft_spi.o
>> > +obj-$(CONFIG_SPI_MEM) += spi-mem.o
>> >  else
>> >  obj-y += spi.o
>> >  obj-$(CONFIG_SOFT_SPI) += soft_spi_legacy.o
>> > diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c
>> > new file mode 100644
>> > index 0000000000..1aabe56819
>> > --- /dev/null
>> > +++ b/drivers/spi/spi-mem.c
>> > @@ -0,0 +1,500 @@
>> > +// SPDX-License-Identifier: GPL-2.0+
>> > +/*
>> > + * Copyright (C) 2018 Exceet Electronics GmbH
>> > + * Copyright (C) 2018 Bootlin
>> > + *
>> > + * Author: Boris Brezillon <boris.brezillon@bootlin.com>
>> > + */
>> > +
>> > +#ifndef __UBOOT__
>> > +#include <linux/dmaengine.h>
>> > +#include <linux/pm_runtime.h>
>> > +#include "internals.h"
>> > +#else
>> > +#include <spi.h>
>> > +#include <spi-mem.h>
>> > +#endif
>> > +
>> > +#ifndef __UBOOT__
>>
>> I would like remove Linux stuff atleast on this file becuase it's
>> difficult for me to read or review the code and also driver/spi have
>> fully u-boot dm stuff. I know it's easy for Linux sync but for this we
>> can do manual sync what ever need. I'm on something what from Linux.
>
> I'm not sure this is a wise idea.
>
> And I don't understand how "driver/spi have fully u-boot dm stuff" is
> related in any manner to this request.

The code in driver/spi is more or less u-boot code it doesn't have
Linux sync. ie reason I want to maintain the similar integrity here,
but on the other-side spi-mem depend more on Linux like MTD. OK let's
move as-it-is like what you added, may be we can simulate if require
in future need.