From: Laurentiu Tudor <laurentiu.tudor@nxp.com>
To: Christoph Hellwig <hch@lst.de>
Cc: "robin.murphy@arm.com" <robin.murphy@arm.com>,
"m.szyprowski@samsung.com" <m.szyprowski@samsung.com>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>, Leo Li <leoyang.li@nxp.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [RFC PATCH] dma-mapping: create iommu mapping for newly allocated dma coherent mem
Date: Thu, 25 Apr 2019 11:30:54 +0000 [thread overview]
Message-ID: <b9f2b425-dde9-f9a1-b8fa-b7710e764b16@nxp.com> (raw)
In-Reply-To: <20190424145705.GB21480@lst.de>
Hi Christoph,
On 24.04.2019 17:57, Christoph Hellwig wrote:
> I'd be happy to offload all of the mentioned tasks to you if you
> volunteer.
Alright, I think I mostly got it and can start with the two usb drivers
you mentioned. Just need a few clarifications, please see inline.
> I think the first step is to move the two USB controller that can only
> DMA to their own BAR off the existing DMA coherent infrastructure. The
> controllers are already identified using the HCD_LOCAL_MEM flag, so we
> just need to key off that in the hcd_buffer_* routines and call into a
So if HCD_LOCAL_MEM is set I should call into the gen_pool api instead
of existing dma_{alloc,free}_coherent().
> genalloc that has been fed using the bar, replacing the current
> dma_declare_coherent usage. Take a look at drivers/pci/p2pdma.c
> for another example of allocating bits of a BAR using genalloc.
Where should I place the reference to the gen_pool? How does local_pool
in 'struct hcd_usb' sound?
---
Thanks & Best Regards, Laurentiu
next prev parent reply other threads:[~2019-04-25 11:31 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-22 16:51 [RFC PATCH] dma-mapping: create iommu mapping for newly allocated dma coherent mem laurentiu.tudor
2019-04-22 18:11 ` Christoph Hellwig
2019-04-23 22:09 ` Laurentiu Tudor
2019-04-24 14:57 ` Christoph Hellwig
2019-04-25 11:30 ` Laurentiu Tudor [this message]
2019-04-26 15:13 ` Christoph Hellwig
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