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From: Russell King - ARM Linux <linux@arm.linux.org.uk>
To: Stephen Boyd <sboyd@codeaurora.org>
Cc: Grant Likely <grant.likely@linaro.org>,
	Stanimir Varbanov <svarbanov@mm-sol.com>,
	Rob Herring <rob.herring@linaro.org>,
	Arnd Bergmann <arnd@arndb.de>,
	devicetree@vger.kernel.org, linux-arm-msm@vger.kernel.org,
	linux-kernel@vger.kernel.org, Mark Brown <broonie@kernel.org>,
	Lee Jones <lee.jones@linaro.org>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] RFC: add function for localbus address
Date: Thu, 23 Oct 2014 00:20:21 +0100	[thread overview]
Message-ID: <20141022232021.GF27405@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <54483746.9060104@codeaurora.org>

On Wed, Oct 22, 2014 at 04:01:26PM -0700, Stephen Boyd wrote:
> Where did this end up? When we talked at Connect I think we settled on
> exploring a driver core specific API like dev_get_localbus_address()
> that calls of_get_localbus_address() for devices with an of_node and in
> the future it could call something like acpi_get_localbus_address() when
> there's an acpi_node. I believe the biggest concern is that we're making
> an API that is OF or platform bus specific when it doesn't need to be.
> Making a driver core specific API avoids this problem by making it bus
> agnostic.

Given how little information there is in the original patch as to exactly
what problem this is addressing, I could be getting the wrong end of the
stick here.

Is this about trying to have a way to obtain the bus local addresses
associated with CPU-view resources?

If so, how about looking towards PCI, which has had this problem for the
last 15+ years, where PCI bus addresses are not necessarily the same as
CPU physical addresses?

There, we don't end up with multiple addresses specified in resources.
We instead have a way to translate between resources and bus-local
addresses, which IMHO is far nicer and less error-prone than having to
specify the same information twice, once with an offset and once without.

-- 
FTTC broadband for 0.8mile line: currently at 9.5Mbps down 400kbps up
according to speedtest.net.

  reply	other threads:[~2014-10-22 23:20 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-07-29 11:42 use IORESOURCE_REG resource type for non-translatable addresses in DT Stanimir Varbanov
2014-07-29 12:00 ` Arnd Bergmann
2014-07-29 14:06   ` Stanimir Varbanov
2014-07-29 15:29     ` Rob Herring
2014-07-29 23:45     ` Grant Likely
2014-07-30  1:07       ` Stephen Boyd
2014-07-30  2:53         ` Rob Herring
2014-07-30  6:06           ` Stephen Boyd
2014-08-27 16:27             ` Stanimir Varbanov
2014-08-27 18:24             ` Bjorn Andersson
2014-08-27 21:55               ` Stephen Boyd
2014-08-29  4:09                 ` Bjorn Andersson
2014-08-28  7:58               ` Stanimir Varbanov
2014-09-02 15:45       ` [PATCH] RFC: add function for localbus address Stanimir Varbanov
2014-09-05 23:29         ` Stephen Boyd
2014-09-08 14:52         ` Grant Likely
2014-09-08 20:22           ` Stephen Boyd
2014-09-08 21:21             ` Mark Brown
2014-09-14  4:46             ` Grant Likely
2014-10-22 23:01               ` Stephen Boyd
2014-10-22 23:20                 ` Russell King - ARM Linux [this message]
2014-10-22 23:53                   ` Stephen Boyd
2014-10-22 23:51                 ` Mark Brown
2014-09-09 15:07           ` Stanimir Varbanov

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