From: Arnd Bergmann <arnd@arndb.de>
To: Russell King - ARM Linux <linux@arm.linux.org.uk>
Cc: Fernando Guzman Lugo <fernando.lugo@ti.com>,
linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, tony@atomide.com,
Ramesh Gupta <grgupta@ti.com>, Hari Kanigeri <h-kanigeri2@ti.com>
Subject: Re: [PATCH] OMAP: iommu flush page table entries from L1 and L2 cache
Date: Mon, 18 Apr 2011 09:29:33 +0200 [thread overview]
Message-ID: <201104180929.33569.arnd@arndb.de> (raw)
In-Reply-To: <20110414223036.GA7335@n2100.arm.linux.org.uk>
On Friday 15 April 2011, Russell King - ARM Linux wrote:
> On Thu, Apr 14, 2011 at 04:52:48PM -0500, Fernando Guzman Lugo wrote:
> > From: Ramesh Gupta <grgupta@ti.com>
> >
> > This patch is to flush the iommu page table entries from L1 and L2
> > caches using dma_map_single. This also simplifies the implementation
> > by removing the functions flush_iopgd_range/flush_iopte_range.
>
> No. This usage is just wrong. If you're going to use the DMA API then
> unmap it, otherwise the DMA API debugging will go awol.
It's also completely upside-down: The iommu support should provide interfaces
using the dma-mapping API, not use that API to provide a machine specific
version of the generic interface.
As far as I can tell, nothing actually uses these drivers, maybe we should just
remove them before we get any code in the mainline kernel that depends on it.
Arnd
WARNING: multiple messages have this Message-ID (diff)
From: arnd@arndb.de (Arnd Bergmann)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] OMAP: iommu flush page table entries from L1 and L2 cache
Date: Mon, 18 Apr 2011 09:29:33 +0200 [thread overview]
Message-ID: <201104180929.33569.arnd@arndb.de> (raw)
In-Reply-To: <20110414223036.GA7335@n2100.arm.linux.org.uk>
On Friday 15 April 2011, Russell King - ARM Linux wrote:
> On Thu, Apr 14, 2011 at 04:52:48PM -0500, Fernando Guzman Lugo wrote:
> > From: Ramesh Gupta <grgupta@ti.com>
> >
> > This patch is to flush the iommu page table entries from L1 and L2
> > caches using dma_map_single. This also simplifies the implementation
> > by removing the functions flush_iopgd_range/flush_iopte_range.
>
> No. This usage is just wrong. If you're going to use the DMA API then
> unmap it, otherwise the DMA API debugging will go awol.
It's also completely upside-down: The iommu support should provide interfaces
using the dma-mapping API, not use that API to provide a machine specific
version of the generic interface.
As far as I can tell, nothing actually uses these drivers, maybe we should just
remove them before we get any code in the mainline kernel that depends on it.
Arnd
next prev parent reply other threads:[~2011-04-18 7:29 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-14 21:52 [PATCH] OMAP: iommu flush page table entries from L1 and L2 cache Fernando Guzman Lugo
2011-04-14 21:52 ` Fernando Guzman Lugo
2011-04-14 21:52 ` Fernando Guzman Lugo
2011-04-14 22:30 ` Russell King - ARM Linux
2011-04-14 22:30 ` Russell King - ARM Linux
2011-04-15 2:24 ` KyongHo Cho
2011-04-15 2:24 ` KyongHo Cho
2011-04-15 8:12 ` Russell King - ARM Linux
2011-04-15 8:12 ` Russell King - ARM Linux
2011-04-15 11:26 ` Gupta, Ramesh
2011-04-15 11:26 ` Gupta, Ramesh
2011-04-28 13:40 ` Russell King - ARM Linux
2011-04-28 13:40 ` Russell King - ARM Linux
2011-04-28 13:40 ` Russell King - ARM Linux
2011-04-28 16:48 ` Gupta, Ramesh
2011-04-28 16:48 ` Gupta, Ramesh
2011-08-11 19:28 ` Gupta, Ramesh
2011-08-11 19:28 ` Gupta, Ramesh
2011-08-11 22:29 ` Russell King - ARM Linux
2011-08-11 22:29 ` Russell King - ARM Linux
2011-08-11 22:29 ` Russell King - ARM Linux
2011-08-12 16:05 ` Gupta, Ramesh
2011-08-12 16:05 ` Gupta, Ramesh
2011-08-12 16:05 ` Gupta, Ramesh
2011-10-16 18:32 ` C.A, Subramaniam
2011-10-16 18:32 ` C.A, Subramaniam
2012-05-29 15:53 ` Gupta, Ramesh
2012-05-29 15:53 ` Gupta, Ramesh
2011-04-18 7:29 ` Arnd Bergmann [this message]
2011-04-18 7:29 ` Arnd Bergmann
2011-04-18 11:05 ` Tony Lindgren
2011-04-18 11:05 ` Tony Lindgren
2011-04-18 11:42 ` Hiroshi DOYU
2011-04-18 11:42 ` Hiroshi DOYU
2011-04-18 13:25 ` Arnd Bergmann
2011-04-18 13:25 ` Arnd Bergmann
2011-04-18 11:58 ` Arnd Bergmann
2011-04-18 11:58 ` Arnd Bergmann
2011-04-18 12:55 ` Kyungmin Park
2011-04-18 12:55 ` Kyungmin Park
2011-04-18 12:55 ` Kyungmin Park
2011-04-18 14:13 ` Arnd Bergmann
2011-04-18 14:13 ` Arnd Bergmann
2011-04-19 9:11 ` Kyungmin Park
2011-04-19 9:11 ` Kyungmin Park
2011-04-19 12:01 ` Arnd Bergmann
2011-04-19 12:01 ` Arnd Bergmann
2011-04-19 12:35 ` Kyungmin Park
2011-04-19 12:35 ` Kyungmin Park
2011-04-19 13:02 ` Russell King - ARM Linux
2011-04-19 13:02 ` Russell King - ARM Linux
2011-04-19 13:11 ` Arnd Bergmann
2011-04-19 13:11 ` Arnd Bergmann
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