From: laurent.pinchart@ideasonboard.com (Laurent Pinchart)
To: linux-arm-kernel@lists.infradead.org
Subject: [Linaro-mm-sig] [PATCH v3 18/19] iommu: exynos: init from dt-specific callback instead of initcall
Date: Wed, 17 Dec 2014 16:39:02 +0200 [thread overview]
Message-ID: <1652261.Tf8nxQyMRf@avalon> (raw)
In-Reply-To: <3015182.XtvMmOW5GD@wuerfel>
Hi Arnd,
On Wednesday 17 December 2014 15:27:36 Arnd Bergmann wrote:
> On Wednesday 17 December 2014 01:24:42 Laurent Pinchart wrote:
> > If we forbid the IOMMU driver from being compiled as a module can't we
> > just rely on deferred probing ? The bus master driver will just be
> > reprobed after the IOMMU gets probed, like for other devices.
> >
> > This could fail in case the IOMMU device permanently fails to probe. There
> > would be something very wrong in the system in that case, Enabling the bus
> > masters totally transparently without IOMMU support could not be such a
> > good idea.
>
> I believe in the majority of cases today, the IOMMU is entirely optional.
> There are valid reasons for not including the IOMMU driver in the kernel,
> e.g. when you know that all the machines with that driver can DMA to
> all of their RAM and you want to avoid the overhead of IOTLB misses.
Should that really be controlled by compiling the IOMMU driver out, wouldn't
it be better to disable the IOMMU devices in DT in that case ?
--
Regards,
Laurent Pinchart
next prev parent reply other threads:[~2014-12-17 14:39 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-19 11:15 [PATCH v3 00/19] Exynos SYSMMU (IOMMU) integration with DT and DMA-mapping subsystem Marek Szyprowski
2014-11-19 11:15 ` [PATCH v3 01/19] iommu: fix const qualifier in of_iommu_set_ops Marek Szyprowski
2014-11-19 11:15 ` [PATCH v3 02/19] iommu: fix initialization without 'add_device' callback Marek Szyprowski
2014-11-19 11:15 ` [PATCH v3 03/19] arm: dma-mapping: add missing check for iommu Marek Szyprowski
2014-11-19 11:15 ` [PATCH v3 04/19] drm: exynos: detach from default dma-mapping domain on init Marek Szyprowski
2014-11-19 11:15 ` [PATCH v3 05/19] arm: exynos: pm_domains: add support for devices registered before arch_initcall Marek Szyprowski
2014-11-19 11:15 ` [PATCH v3 06/19] ARM: dts: exynos4: add sysmmu nodes Marek Szyprowski
2014-11-19 11:15 ` [PATCH v3 07/19] iommu: exynos: don't read version register on every tlb operation Marek Szyprowski
2014-11-19 11:15 ` [PATCH v3 08/19] iommu: exynos: remove unused functions Marek Szyprowski
2014-11-19 11:15 ` [PATCH v3 09/19] iommu: exynos: remove useless spinlock Marek Szyprowski
2014-11-19 11:15 ` [PATCH v3 10/19] iommu: exynos: refactor function parameters to simplify code Marek Szyprowski
2014-11-19 11:15 ` [PATCH v3 11/19] iommu: exynos: remove unused functions, part 2 Marek Szyprowski
2014-11-19 11:15 ` [PATCH v3 12/19] iommu: exynos: remove useless device_add/remove callbacks Marek Szyprowski
2014-11-19 11:15 ` [PATCH v3 13/19] iommu: exynos: add support for binding more than one sysmmu to master device Marek Szyprowski
2014-11-19 11:15 ` [PATCH v3 14/19] iommu: exynos: add support for runtime_pm Marek Szyprowski
2014-11-19 11:15 ` [PATCH v3 15/19] iommu: exynos: rename variables to reflect their purpose Marek Szyprowski
2014-11-19 11:15 ` [PATCH v3 16/19] iommu: exynos: document internal structures Marek Szyprowski
2014-11-19 11:15 ` [PATCH v3 17/19] iommu: exynos: remove excessive includes and sort others alphabetically Marek Szyprowski
2014-11-19 11:15 ` [PATCH v3 18/19] iommu: exynos: init from dt-specific callback instead of initcall Marek Szyprowski
2014-12-14 12:45 ` Laurent Pinchart
2014-12-15 9:47 ` Thierry Reding
2014-12-15 17:17 ` Will Deacon
2014-12-15 17:27 ` Laurent Pinchart
2014-12-15 17:43 ` Will Deacon
2014-12-15 17:53 ` Laurent Pinchart
2014-12-15 18:13 ` Will Deacon
2014-12-15 18:19 ` Laurent Pinchart
2014-12-16 10:58 ` Marek Szyprowski
2014-12-16 11:40 ` Arnd Bergmann
2014-12-16 12:07 ` Laurent Pinchart
2014-12-16 12:10 ` [Linaro-mm-sig] " Arnd Bergmann
2014-12-16 23:24 ` Laurent Pinchart
2014-12-17 14:27 ` Arnd Bergmann
2014-12-17 14:39 ` Laurent Pinchart [this message]
2014-12-17 15:41 ` Arnd Bergmann
2014-12-17 16:02 ` Laurent Pinchart
2014-12-17 21:58 ` Arnd Bergmann
2014-12-17 22:38 ` Laurent Pinchart
2014-12-17 14:53 ` Lucas Stach
2014-12-17 15:56 ` Arnd Bergmann
2014-12-18 20:36 ` Laurent Pinchart
2014-12-18 23:21 ` Arnd Bergmann
2014-11-19 11:15 ` [PATCH v3 19/19] iommu: exynos: add callback for initializing devices from device tree Marek Szyprowski
2014-12-02 9:59 ` [PATCH v3 00/19] Exynos SYSMMU (IOMMU) integration with DT and DMA-mapping subsystem Sjoerd Simons
2014-12-05 10:22 ` Marek Szyprowski
2015-01-06 9:49 ` Javier Martinez Canillas
2015-01-07 2:03 ` Joonyoung Shim
2015-01-07 9:33 ` Javier Martinez Canillas
2015-01-07 9:55 ` Joonyoung Shim
2015-01-08 16:42 ` Javier Martinez Canillas
2015-01-12 6:40 ` Joonyoung Shim
2015-01-12 9:43 ` Joonyoung Shim
2015-01-12 16:09 ` Javier Martinez Canillas
2015-01-13 5:24 ` Joonyoung Shim
2015-01-13 8:40 ` Joonyoung Shim
2015-01-13 9:43 ` Javier Martinez Canillas
2015-01-13 9:21 ` Javier Martinez Canillas
2015-01-14 0:19 ` Javier Martinez Canillas
2015-01-14 0:24 ` Javier Martinez Canillas
2015-01-20 11:12 ` Joonyoung Shim
2015-01-20 14:05 ` Javier Martinez Canillas
2015-01-16 10:33 ` Marek Szyprowski
2015-01-16 15:44 ` Sjoerd Simons
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