Re: [PATCH 2/2][v5] driver: mtd: update struct map_info's swap as per map requirement

Boris Brezillon
2018-03-06T08:14:11Z

Hi Prabhakar,

On Tue, 6 Mar 2018 06:02:08 +0000
Prabhakar Kushwaha <prabhakar.kushwaha@nxp.com> wrote:

> Dear Boris,
>
> > -----Original Message-----
> > From: Prabhakar Kushwaha
> > Sent: Wednesday, February 28, 2018 1:04 PM
> > To: linux-mtd@lists.infradead.org; devicetree@vger.kernel.org;
> > robh@kernel.org; mark.rutland@arm.com; shawnguo@kernel.org
> > Cc: linux-arm-kernel@lists.infradead.org; boris.brezillon@free-
> > electrons.com; cyrille.pitchen@wedev4u.fr; computersforpeace@gmail.com;
> > oss@buserror.net; Leo Li <leoyang.li@nxp.com>; Prabhakar Kushwaha
> > <prabhakar.kushwaha@nxp.com>; Jagdish Gediya
> > <jagdish.gediya@nxp.com>
> > Subject: [PATCH 2/2][v5] driver: mtd: update struct map_info's swap as per
> > map requirement
> >
> > It is not necessary for all device's maps to be CFI_HOST_ENDIAN.
> > Maps device can be Big endian or little endian.
> >
> > Currently it is being taken care using CONFIG_MTD_CFI_LE_BYTE_SWAP or
> > CONFIG_MTD_CFI_BE_BYTE_SWAP i.e. compile time.
> >
> > Now update struct map_info's swap field based on device characteristics
> > defined in device tree.
> >
> > Signed-off-by: Jagdish Gediya <jagdish.gediya@nxp.com>
> > Signed-off-by: Prabhakar Kushwaha <prabhakar.kushwaha@nxp.com>
> > ---
> > Changes for v2: Incorporated review comments from Boris Brezillon
> > http://patchwork.ozlabs.org/patch/758381/
> > Changes for v3: None
> > Changes for v4: Updated code as per new defined binding of physmap.txt
> > Changes for v5: Avoid map.swap set in case of endiannes not defined in dts
> > file
> >
> > drivers/mtd/maps/physmap_of_core.c | 6 ++++++
> > 1 file changed, 6 insertions(+)
> >
> > diff --git a/drivers/mtd/maps/physmap_of_core.c
> > b/drivers/mtd/maps/physmap_of_core.c
> > index b1bd4faecfb2..527b1682381f 100644
> > --- a/drivers/mtd/maps/physmap_of_core.c
> > +++ b/drivers/mtd/maps/physmap_of_core.c
> > @@ -20,6 +20,7 @@
> > #include <linux/mtd/map.h>
> > #include <linux/mtd/partitions.h>
> > #include <linux/mtd/concat.h>
> > +#include <linux/mtd/cfi_endian.h>
> > #include <linux/of.h>
> > #include <linux/of_address.h>
> > #include <linux/of_platform.h>
> > @@ -233,6 +234,11 @@ static int of_flash_probe(struct platform_device
> > *dev)
> > info->list[i].map.bankwidth = be32_to_cpup(width);
> > info->list[i].map.device_node = dp;
> >
> > + if (of_property_read_bool(dp, "big-endian"))
> > + info->list[i].map.swap = CFI_BIG_ENDIAN;
> > + else if (of_property_read_bool(dp, "little-endian"))
> > + info->list[i].map.swap = CFI_LITTLE_ENDIAN;
> > +
> > err = of_flash_probe_gemini(dev, dp, &info->list[i].map);
> > if (err)
> > goto err_out;
> > --
> > 2.14.1
>
> Is this patch correct with respect to device binding (http://patchwork.ozlabs.org/patch/878974/)

This patch looks good, but patch 1 is not describing what really
happens when the xxx-endian props are missing.

> May I go ahead and send device tree patches for other NXP platforms

Nope, please wait till we sorted out the last issues I pointed on patch
1.

>
> will http://patchwork.ozlabs.org/patch/878974/ along with this patch be send via linux-mtd repo?

Yes, once you've fixed the description or explained why you think the
current description is valid.

Regards,

Boris

--
Boris Brezillon, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering