From: t.figa@samsung•com (Tomasz Figa)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v11 20/27] iommu/exynos: allow having multiple System MMUs for a master H/W
Date: Fri, 14 Mar 2014 17:12:03 +0100 [thread overview]
Message-ID: <53232A53.4040708@samsung.com> (raw)
In-Reply-To: <20140314141050.c8bedcb66532d277c496796d@samsung.com>
Hi KyongHo,
On 14.03.2014 06:10, Cho KyongHo wrote:
> Some master device descriptor like fimc-is which is an abstraction
> of very complex H/W may have multiple System MMUs. For those devices,
> the design of the link between System MMU and its master H/W is needed
> to be reconsidered.
>
> A link structure, sysmmu_list_data is introduced that provides a link
> to master H/W and that has a pointer to the device descriptor of a
> System MMU. Given a device descriptor of a master H/W, it is possible
> to traverse all System MMUs that must be controlled along with the
> master H/W.
NAK.
A device driver should handle particular hardware instances separately,
without abstracting a virtual hardware instance consisting of multiple
physical ones.
If such abstraction is needed, it should be done above the exynos-iommu
driver, e.g. by something like iommu-composite driver that would
aggregate several IOMMUs. Keep in mind that such IOMMUs in a group could
be different, e.g. different Exynos SysMMU versions or even completely
different IPs handled by different drivers.
Still, I don't think there is a real need for such abstraction. Instead,
related drivers shall be fixed to properly handle multiple memory
masters and their IOMMUs.
Best regards,
Tomasz
next prev parent reply other threads:[~2014-03-14 16:12 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-14 5:10 [PATCH v11 20/27] iommu/exynos: allow having multiple System MMUs for a master H/W Cho KyongHo
2014-03-14 16:12 ` Tomasz Figa [this message]
2014-03-18 13:01 ` Cho KyongHo
2014-03-18 14:26 ` Tomasz Figa
2014-03-19 0:39 ` Cho KyongHo
2014-03-19 13:20 ` Tomasz Figa
2014-03-19 15:14 ` Tomasz Figa
2014-03-20 10:22 ` Cho KyongHo
2014-03-20 10:54 ` Tomasz Figa
2014-03-21 5:21 ` Cho KyongHo
2014-03-21 10:07 ` Tomasz Figa
2014-04-22 13:23 ` Shaik Ameer Basha
2014-04-23 1:15 ` Cho KyongHo
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