From: Christian Eggers <ceggers@arri.de>
To: David Laight <David.Laight@aculab.com>
Cc: Arnd Bergmann <arnd@arndb.de>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"stable@vger.kernel.org" <stable@vger.kernel.org>
Subject: Re: [PATCH] eeprom: at25: set minimum read/write access stride to 1
Date: Tue, 28 Jul 2020 14:03:30 +0200 [thread overview]
Message-ID: <2379124.UCELOXW4Ax@n95hx1g2> (raw)
In-Reply-To: <02cb3be60abf4a54affe239009c6e157@AcuMS.aculab.com>
On Tuesday, 28 July 2020, 13:20:15 CEST, David Laight wrote:
> From: Christian Eggers
>
> > &spi {
> > ....
> > fram: fram@0 {
> > ...
> > mac_address_fec2: mac-address@126 {
> > reg = <0x126 6>;
> > };
> > ...
> > };
> > };
>
>
> Hmmmm.... the 'stride' only constrains the alignment of 'cells'.
> (ie address ranges from the device tree.)
My mac-address is not aligned to 4 bytes...
> It looks as though you can open the entire NVMEM device and
> then do reads from byte offsets.
> The 'stride' and 'word_size' are then not checked!
When I set back the stride to 4, I get the following errors:
[ 6.998788] 000: nvmem spi0.00: cell mac-address unaligned to nvmem stride 4
[ 6.998902] 000: at25: probe of spi0.0 failed with error -22
...
[ 7.146454] 000: fec 20b4000.ethernet: Invalid MAC address: 00:00:00:00:00:00
[ 7.146480] 000: fec 20b4000.ethernet: Using random MAC address: 6e:9d:37:49:6d:15
> Actually it might be that before 01973a01f9ec3 byte aligned
> 'cells' were allowed.
I use linux-5.4.x (latest), the mentioned patch has been included long time ago.
regards
Christian
prev parent reply other threads:[~2020-07-28 12:13 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-28 9:29 [PATCH] eeprom: at25: set minimum read/write access stride to 1 Christian Eggers
2020-07-28 9:52 ` David Laight
2020-07-28 10:30 ` Christian Eggers
2020-07-28 11:20 ` David Laight
2020-07-28 12:03 ` Christian Eggers [this message]
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