From: Stephen Warren <swarren@wwwdotorg.org>
To: Thierry Reding <thierry.reding@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Grant Likely <grant.likely@linaro.org>,
Rob Herring <rob.herring@calxeda.com>,
Hiroshi Doyu <hdoyu@nvidia.com>,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>,
devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC 2/4] driver core: Allow early registration of devices
Date: Mon, 19 Aug 2013 13:43:59 -0600 [thread overview]
Message-ID: <5212757F.2080107@wwwdotorg.org> (raw)
In-Reply-To: <20130817111747.GB1536@mithrandir>
On 08/17/2013 05:17 AM, Thierry Reding wrote:
...
> Well, the most obvious cases where early initialization is needed
> are interrupt controllers and clocks.
... and IOMMUs, which apparently need to initialize before any devices
whose transactions are routed through the IOMMU, in order to set
themselves up as the IOMMU for the relevant devices.
It's possible that the CPU-visible bus structure isn't a strict
inverse/reverse of the device-visible bus-structure. A device may have
CPU-visible registers on one bus segment, but inject master
transactions onto an unrelated bus segment. So it may not be as simple
as making a bus driver for the bus segment affected by the IOMMU, and
having that driver trigger instantiation of all its children.
next prev parent reply other threads:[~2013-08-19 19:44 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-16 20:39 [RFC 0/4] Early device registration Thierry Reding
2013-08-16 20:39 ` [RFC 1/4] driver core: Register SoC bus after platform bus Thierry Reding
2013-08-16 20:39 ` [RFC 2/4] driver core: Allow early registration of devices Thierry Reding
2013-08-16 21:06 ` Greg Kroah-Hartman
2013-08-16 21:55 ` Thierry Reding
2013-08-16 22:08 ` Greg Kroah-Hartman
2013-08-17 11:17 ` Thierry Reding
2013-08-19 19:43 ` Stephen Warren [this message]
2013-08-19 20:10 ` Thierry Reding
2013-08-19 20:53 ` Stephen Warren
2013-08-19 21:41 ` Thierry Reding
2013-08-16 22:20 ` Grant Likely
2013-08-16 22:35 ` Greg Kroah-Hartman
2013-08-17 10:26 ` Tomasz Figa
2013-08-19 19:49 ` Stephen Warren
2013-08-19 20:04 ` Thierry Reding
2013-08-17 11:07 ` Thierry Reding
2013-08-16 20:39 ` [RFC 3/4] ARM: tegra: Call of_platform_populate() early Thierry Reding
2013-08-16 20:39 ` [RFC 4/4] OF: Add device pointer to struct device_node Thierry Reding
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