From: ezequiel.garcia@free-electrons.com (Ezequiel Garcia)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 04/10] bus: introduce an Marvell EBU MBus driver
Date: Thu, 7 Mar 2013 19:20:05 -0300 [thread overview]
Message-ID: <20130307222004.GA2450@localhost> (raw)
In-Reply-To: <20130306230412.GA5870@obsidianresearch.com>
Hi Jason,
On Wed, Mar 06, 2013 at 04:04:12PM -0700, Jason Gunthorpe wrote:
>
> nor at 0 {
> compatible = 'linux mtd nor driver';
> regs = <MAPDEF(1, 0xab, MAPDEF_NOMASK) 0x10000>;
> }
>
> We can now tell directly that 'linux mtd nor driver' is behind MBUS
> target 0xab, and the OF code already knows the base for this MBUS
> target from the ranges property, as modified by the MBUS driver. The
> MBUS driver also knows which targets to configure windows for
> immediately at boot without having to consult internal tables. Plus we
> don't need to modify the NOR driver to call out to MBUS window
> functions to fetch an address.
>
> There are a few other variants on how to do this in DT, but they all
> come down to modeling the MBUS target using a ranges property and
> having the mbus driver adjust the range mapping at runtime.
>
At least in the flash (NOR and friends) case, this is not necessarily true.
Now that the Device Bus driver is posted I think we have a nice example
on how address decoding windows would be allocated through the mbus
driver, *without* touching the child driver (i.e. NOR driver).
The windows are allocated as part of the "preparing" tasks the Device
Bus does as the parent device and it seems like a very clean solution.
The windows are specifically related to him, so I think this driver is
the most appropriate to perform the window management.
In a certain way, this is similar to other memory-controller devices
(e.g. OMAP's GPMC) that need to request a chip select before the child
device can be accessed.
Moreover -as I already stated in the patchset- I believe we can make the
Device Bus implement dynamic window allocation, if he can't find a 'ranges'
property for a given child.
In conclusion: there is absolutely no need to change the NOR driver,
and there is no need to explictly add an explicit description of the
NOR window in the device tree.
Thanks,
--
Ezequiel Garc?a, Free Electrons
Embedded Linux, Kernel and Android Engineering
http://free-electrons.com
next prev parent reply other threads:[~2013-03-07 22:20 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-06 13:43 [PATCH 3.10] Introduce a Marvell EBU MBus driver Thomas Petazzoni
2013-03-06 13:43 ` [PATCH 01/10] arm: plat-orion: only build addr-map.c when needed Thomas Petazzoni
2013-03-06 13:43 ` [PATCH 02/10] arm: plat-orion: use mv_mbus_dram_info() in PCIe code Thomas Petazzoni
2013-03-06 13:43 ` [PATCH 03/10] arm: mach-orion5x: use mv_mbus_dram_info() in PCI code Thomas Petazzoni
2013-03-06 13:43 ` [PATCH 04/10] bus: introduce an Marvell EBU MBus driver Thomas Petazzoni
2013-03-06 19:08 ` Jason Gunthorpe
2013-03-06 19:27 ` Thomas Petazzoni
2013-03-06 20:24 ` Jason Gunthorpe
2013-03-06 20:40 ` Thomas Petazzoni
2013-03-06 21:50 ` Jason Gunthorpe
2013-03-06 22:27 ` Jason Cooper
2013-03-06 23:04 ` Jason Gunthorpe
2013-03-07 10:39 ` Thomas Petazzoni
2013-03-08 13:50 ` Arnd Bergmann
2013-03-08 14:06 ` Thomas Petazzoni
2013-03-08 15:41 ` Arnd Bergmann
2013-03-08 17:50 ` Jason Gunthorpe
2013-03-08 19:42 ` Arnd Bergmann
2013-03-08 20:05 ` Jason Gunthorpe
2013-03-08 22:46 ` Arnd Bergmann
2013-03-08 17:43 ` Jason Gunthorpe
2013-03-08 22:58 ` Arnd Bergmann
2013-03-07 22:20 ` Ezequiel Garcia [this message]
2013-03-07 23:05 ` Jason Gunthorpe
2013-03-08 1:02 ` Ezequiel Garcia
2013-03-08 8:10 ` Thomas Petazzoni
2013-03-08 17:29 ` Jason Gunthorpe
2013-03-08 17:59 ` Ezequiel Garcia
2013-03-08 18:31 ` Jason Gunthorpe
2013-03-08 18:53 ` Ezequiel Garcia
2013-03-18 16:27 ` Thomas Petazzoni
2013-03-18 17:18 ` Jason Gunthorpe
2013-03-08 15:59 ` Maxime Bizon
2013-03-08 16:48 ` Jason Gunthorpe
2013-03-08 17:12 ` Ezequiel Garcia
2013-03-08 8:14 ` Thomas Petazzoni
2013-03-08 18:26 ` Jason Gunthorpe
2013-03-07 3:50 ` Arnd Bergmann
2013-03-07 3:37 ` Arnd Bergmann
2013-03-07 6:35 ` Jason Gunthorpe
2013-03-08 16:48 ` Jason Cooper
2013-03-08 19:47 ` Jason Gunthorpe
2013-03-08 22:54 ` Arnd Bergmann
2013-03-07 10:58 ` Thomas Petazzoni
2013-03-07 17:37 ` Jason Gunthorpe
2013-03-07 19:11 ` Thomas Petazzoni
2013-03-07 19:55 ` Jason Gunthorpe
2013-03-07 20:28 ` Thomas Petazzoni
2013-03-07 20:47 ` Jason Gunthorpe
2013-03-06 13:43 ` [PATCH 05/10] arm: mach-mvebu: convert to use mvebu-mbus driver Thomas Petazzoni
2013-03-06 13:58 ` Thomas Petazzoni
2013-03-06 13:43 ` [PATCH 06/10] arm: mach-kirkwood: " Thomas Petazzoni
2013-03-06 19:09 ` Jason Gunthorpe
2013-03-06 19:31 ` Thomas Petazzoni
2013-03-06 13:43 ` [PATCH 07/10] arm: mach-dove: " Thomas Petazzoni
2013-03-06 13:43 ` [PATCH 08/10] arm: mach-orion5x: " Thomas Petazzoni
2013-03-06 13:43 ` [PATCH 09/10] arm: mach-mv78xx0: convert to use the " Thomas Petazzoni
2013-03-06 13:43 ` [PATCH 10/10] arm: plat-orion: remove addr-map code Thomas Petazzoni
2013-03-06 16:59 [PATCH v2 for 3.10] Introduce a Marvell EBU MBus driver Thomas Petazzoni
2013-03-06 16:59 ` [PATCH 04/10] bus: introduce an " Thomas Petazzoni
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=20130307222004.GA2450@localhost \
--to=ezequiel.garcia@free-electrons.com \
--cc=linux-arm-kernel@lists.infradead.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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).