From: hch@infradead.org (Christoph Hellwig)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC 2/3] USB: core: Add non-coherent buffer allocation helpers
Date: Thu, 30 Aug 2018 22:50:47 -0700 [thread overview]
Message-ID: <20180831055047.GA9140@infradead.org> (raw)
In-Reply-To: <4fc5107f93871599ead017af7ad50f22535a7683.camel@collabora.com>
On Thu, Aug 30, 2018 at 07:11:35PM -0300, Ezequiel Garcia wrote:
> On Thu, 2018-08-30 at 10:58 -0700, Christoph Hellwig wrote:
> > Please don't introduce new DMA_ATTR_NON_CONSISTENT users, it is
> > a rather horrible interface, and I plan to kill it off rather sooner
> > than later. I plan to post some patches for a better interface
> > that can reuse the normal dma_sync_single_* interfaces for ownership
> > transfers. I can happily include usb in that initial patch set based
> > on your work here if that helps.
>
> Please do. Until we have proper allocators that go thru the DMA API,
> drivers will have to kmalloc the USB transfer buffers, and have
> streaming mappings. Which in turns mean not using IOMMU or CMA.
dma_map_page will of course use the iommu.
next prev parent reply other threads:[~2018-08-31 5:50 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-30 17:20 [RFC 0/3] Introduce usb_{alloc,free}_noncoherent API Ezequiel Garcia
2018-08-30 17:20 ` [RFC 1/3] HACK: ARM: dma-mapping: Get writeback memory for non-consistent mappings Ezequiel Garcia
2018-08-30 17:20 ` [RFC 2/3] USB: core: Add non-coherent buffer allocation helpers Ezequiel Garcia
2018-08-30 17:58 ` Christoph Hellwig
2018-08-30 22:11 ` Ezequiel Garcia
2018-08-31 5:50 ` Christoph Hellwig [this message]
2018-08-31 6:51 ` Tomasz Figa
2018-10-31 1:55 ` Tomasz Figa
2018-08-30 17:20 ` [RFC 3/3] stk1160: Use non-coherent buffers for USB transfers Ezequiel Garcia
2018-08-30 17:59 ` Christoph Hellwig
2018-09-07 8:54 ` Tomasz Figa
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