[PATCH 3/4] mtd: rawnand: brcmnand: Add BCMBCA read data bus interface

[Michael Nazzareno Trimarchi]

Hi all

On Fri, Nov 8, 2024 at 3:22 AM William Zhang <william.zhang at broadcom.com> wrote:
>
> Hi Linus,
>
> > -----Original Message-----
> > From: Linus Walleij <linus.walleij at linaro.org>
> > Sent: Thursday, November 7, 2024 6:16 AM
> > To: david regan <dregan at broadcom.com>
> > Cc: u-boot <u-boot at lists.denx.de>; Dario Binacchi
> > <dario.binacchi at amarulasolutions.com>; Michael Trimarchi
> > <michael at amarulasolutions.com>; Anand Gore
> > <anand.gore at broadcom.com>; William Zhang
> > <william.zhang at broadcom.com>; Kursad Oney
> > <kursad.oney at broadcom.com>; Philippe Reynes
> > <philippe.reynes at softathome.com>; Florian Fainelli
> > <florian.fainelli at broadcom.com>; Miquel Raynal
> > <miquel.raynal at bootlin.com>; Kamal Dasu <kamal.dasu at broadcom.com>;
> > David Regan <dregan at mail.com>; Tom Rini <trini at konsulko.com>; Jiaxun
> > Yang <jiaxun.yang at flygoat.com>
> > Subject: Re: [PATCH 3/4] mtd: rawnand: brcmnand: Add BCMBCA read data
> > bus interface
> >
> > On Wed, Nov 6, 2024 at 10:04 PM david regan <dregan at broadcom.com>
> > wrote:
> >
> > > The BCMBCA broadband SoC integrates the NAND controller differently than
> > > STB, iProc and other SoCs.  It has different endianness for NAND cache
> > > data.
> > >
> > > Add a SoC read data bus shim for BCMBCA to meet the specific SoC need
> > > and performance improvement using the optimized memcpy function on
> > NAND
> > > cache memory.
> > >
> > > This is a port of the upstream Linux patch to U-Boot.
> > >
> > > https://lore.kernel.org/linux-mtd/20240223034758.13753-12-
> > william.zhang at broadcom.com/
> > >
> > > Signed-off-by: david regan <dregan at broadcom.com>
> >
> > The patch looks fine, but shouldn't the existing brcmnand_read_data_bus()
> > in drivers/mtd/nand/raw/brcmnand/brcmnand.c also be replaced with
> > brcmnand_soc_data_bus_read()?
> >
> > Maybe this is a problem in the upstream kernel driver though :/
> >
> The upstream kernel driver is correct because it uses exec_op to read the
> parameter
> page/ONFI data but exec_op is not available to the u-boot code base.  So
> this new function
> brcmnand_soc_data_bus_read tries to do that in generic way to handle the
> endianness
> difference between platforms. But I agree it causes confusing to existing
> brcmnand_read_data_bus.
>
> We are working on a better solution and will update.
>
> > Yours,
> > Linus Walleij

I'm thinking of applying this series for a general cleanup. What would
like to have in cover letter, is what board
this series was tested, due the fact that some of the code is not
necessary anymore

Michael



-- 
Michael Nazzareno Trimarchi
Co-Founder & Chief Executive Officer
M. +39 347 913 2170
michael at amarulasolutions.com
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