Linux-PCI Archive on lore.kernel.org
 help / color / Atom feed
From: Arnd Bergmann <arnd@arndb.de>
To: Daniel Gutson <daniel@eclypsium.com>
Cc: Derek Kiernan <derek.kiernan@xilinx.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Mauro Carvalho Chehab <mchehab+huawei@kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Richard Hughes <hughsient@gmail.com>,
	Alex Bazhaniuk <alex@eclypsium.com>,
	linux-pci <linux-pci@vger.kernel.org>
Subject: Re: [PATCH] SPI LPC information kernel module
Date: Mon, 6 Jul 2020 12:22:17 +0200
Message-ID: <CAK8P3a3rkiBMB55HJGi8T4Nw4gUrG2M=BAq+w=WMbS8DzwnPqw@mail.gmail.com> (raw)
In-Reply-To: <CAFmMkTE3z6OZQ_v3jx-4MzMr8v+4qcF2uLn0ASGydj5oqDnfjg@mail.gmail.com>

On Fri, Jul 3, 2020 at 10:43 PM Daniel Gutson <daniel@eclypsium.com> wrote:

> After analyzing the intel-spi driver, I came up to these observations that led me conclude that it is not what I need to use:
>
> * Some SPI Controllers have 0xFFFF as their VID DID bytes in the PCI config space. This causes that the PCI devices enumeration doesn't include them,
> and thus a PCI device driver won't be probed even despite listing the DID that the datasheet specifies. I effectively confirmed this by doing a PCI device driver and
> trying the intel-spi in systems with this characteristic. In short, the intel-spi driver doesn't work with these systems.

Maybe this part can be handled with a fixup in drivers/pci that
changes the effective
PCI device ID on the systems that do need to access the device.

Adding the PCI mailing list for other ideas. Basically it sounds like
the BIOS has
intentionally configured the SPI-NOR device to be hidden from PCI probing to
prevent operating systems from accessing it, but you want to ignore that and
access it anyway, correct?

      Arnd

           reply index

Thread overview: expand[flat|nested]  mbox.gz  Atom feed
 [parent not found: <CAFmMkTE3z6OZQ_v3jx-4MzMr8v+4qcF2uLn0ASGydj5oqDnfjg@mail.gmail.com>]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to='CAK8P3a3rkiBMB55HJGi8T4Nw4gUrG2M=BAq+w=WMbS8DzwnPqw@mail.gmail.com' \
    --to=arnd@arndb.de \
    --cc=alex@eclypsium.com \
    --cc=daniel@eclypsium.com \
    --cc=derek.kiernan@xilinx.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=hughsient@gmail.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-pci@vger.kernel.org \
    --cc=mchehab+huawei@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-PCI Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-pci/0 linux-pci/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-pci linux-pci/ https://lore.kernel.org/linux-pci \
		linux-pci@vger.kernel.org
	public-inbox-index linux-pci

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-pci


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git