From: Yong Wu <yong.wu-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
To: Robin Murphy <robin.murphy-5wv7dgnIgG8@public.gmane.org>
Cc: "laurent.pinchart+renesas-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org"
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<arnd-r2nGTMty4D4@public.gmane.org>,
Catalin Marinas <Catalin.Marinas-5wv7dgnIgG8@public.gmane.org>,
Will Deacon <Will.Deacon-5wv7dgnIgG8@public.gmane.org>,
"tomasz.figa-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org"
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<linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org>
Subject: Re: [PATCH v2 2/4] iommu: Implement common IOMMU ops for DMA mapping
Date: Fri, 19 Jun 2015 09:06:12 +0800 [thread overview]
Message-ID: <1434675972.30129.0.camel@mhfsdcap03> (raw)
In-Reply-To: <5582F7C5.8060901-5wv7dgnIgG8@public.gmane.org>
On Thu, 2015-06-18 at 17:54 +0100, Robin Murphy wrote:
> On 18/06/15 16:00, Yong Wu wrote:
> > Hi Robin,
> > while our drm test, we meet a problem while dma-mmap.
> >
> > On Thu, 2015-06-11 at 16:54 +0100, Robin Murphy wrote:
> >> Taking inspiration from the existing arch/arm code, break out some
> >> generic functions to interface the DMA-API to the IOMMU-API. This will
> >> do the bulk of the heavy lifting for IOMMU-backed dma-mapping.
> >>
> >> Signed-off-by: Robin Murphy <robin.murphy-5wv7dgnIgG8@public.gmane.org>
> >> ---
> >> drivers/iommu/Kconfig | 7 +
> >> drivers/iommu/Makefile | 1 +
> >> drivers/iommu/dma-iommu.c | 560 ++++++++++++++++++++++++++++++++++++++++++++++
> >> include/linux/dma-iommu.h | 94 ++++++++
> >> 4 files changed, 662 insertions(+)
> >> create mode 100644 drivers/iommu/dma-iommu.c
> >> create mode 100644 include/linux/dma-iommu.h
> >>
> > [snip]
> >> +/**
> >> + * iommu_dma_mmap - Map a buffer into provided user VMA
> >> + * @pages: Array representing buffer from iommu_dma_alloc()
> >> + * @size: Size of buffer in bytes
> >> + * @vma: VMA describing requested userspace mapping
> >> + *
> >> + * Maps the pages of the buffer in @pages into @vma. The caller is responsible
> >> + * for verifying the correct size and protection of @vma beforehand.
> >> + */
> >> +
> >> +int iommu_dma_mmap(struct page **pages, size_t size, struct vm_area_struct *vma)
> >> +{
> >> + unsigned long uaddr = vma->vm_start;
> >> + unsigned int i, count = PAGE_ALIGN(size) >> PAGE_SHIFT;
> >> + int ret = -ENXIO;
> >> +
> >> + for (i = vma->vm_pgoff; i < count && uaddr < vma->vm_end; i++) {
> > Is it : for (i = 0; i < count && uaddr < vma->vm_end; i++)
>
> According to the patches at [1], respecting vma->pgoff is necessary for
> users who only want to mmap part of the buffer. Does your DRM driver by
> any chance need the same fix as the Rockchip one?
Thanks. We will try to add it.
>
> >> + ret = vm_insert_page(vma, uaddr, pages[i]);
> >> + if (ret)
> >> + break;
> >> + uaddr += PAGE_SIZE;
> >> + }
> >> + return ret;
> >> +}
> >> +
>
> And to save another email:
>
> >> + if (WARN_ON(!area || area->pages))
> > Is it: if (WARN_ON(!area || !area->pages))
> >> + return -ENXIO;
>
> You're absolutely right, thanks. I've got a couple more bugfixes in
> progress too, so I'll try to get an updated branch pushed out soon; I'll
> hold off posting a v3 to the list until after the upcoming merge window,
> though.
>
> Robin.
>
> [1]:http://thread.gmane.org/gmane.linux.kernel/1932343
>
WARNING: multiple messages have this Message-ID (diff)
From: yong.wu@mediatek.com (Yong Wu)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 2/4] iommu: Implement common IOMMU ops for DMA mapping
Date: Fri, 19 Jun 2015 09:06:12 +0800 [thread overview]
Message-ID: <1434675972.30129.0.camel@mhfsdcap03> (raw)
In-Reply-To: <5582F7C5.8060901@arm.com>
On Thu, 2015-06-18 at 17:54 +0100, Robin Murphy wrote:
> On 18/06/15 16:00, Yong Wu wrote:
> > Hi Robin,
> > while our drm test, we meet a problem while dma-mmap.
> >
> > On Thu, 2015-06-11 at 16:54 +0100, Robin Murphy wrote:
> >> Taking inspiration from the existing arch/arm code, break out some
> >> generic functions to interface the DMA-API to the IOMMU-API. This will
> >> do the bulk of the heavy lifting for IOMMU-backed dma-mapping.
> >>
> >> Signed-off-by: Robin Murphy <robin.murphy@arm.com>
> >> ---
> >> drivers/iommu/Kconfig | 7 +
> >> drivers/iommu/Makefile | 1 +
> >> drivers/iommu/dma-iommu.c | 560 ++++++++++++++++++++++++++++++++++++++++++++++
> >> include/linux/dma-iommu.h | 94 ++++++++
> >> 4 files changed, 662 insertions(+)
> >> create mode 100644 drivers/iommu/dma-iommu.c
> >> create mode 100644 include/linux/dma-iommu.h
> >>
> > [snip]
> >> +/**
> >> + * iommu_dma_mmap - Map a buffer into provided user VMA
> >> + * @pages: Array representing buffer from iommu_dma_alloc()
> >> + * @size: Size of buffer in bytes
> >> + * @vma: VMA describing requested userspace mapping
> >> + *
> >> + * Maps the pages of the buffer in @pages into @vma. The caller is responsible
> >> + * for verifying the correct size and protection of @vma beforehand.
> >> + */
> >> +
> >> +int iommu_dma_mmap(struct page **pages, size_t size, struct vm_area_struct *vma)
> >> +{
> >> + unsigned long uaddr = vma->vm_start;
> >> + unsigned int i, count = PAGE_ALIGN(size) >> PAGE_SHIFT;
> >> + int ret = -ENXIO;
> >> +
> >> + for (i = vma->vm_pgoff; i < count && uaddr < vma->vm_end; i++) {
> > Is it : for (i = 0; i < count && uaddr < vma->vm_end; i++)
>
> According to the patches at [1], respecting vma->pgoff is necessary for
> users who only want to mmap part of the buffer. Does your DRM driver by
> any chance need the same fix as the Rockchip one?
Thanks. We will try to add it.
>
> >> + ret = vm_insert_page(vma, uaddr, pages[i]);
> >> + if (ret)
> >> + break;
> >> + uaddr += PAGE_SIZE;
> >> + }
> >> + return ret;
> >> +}
> >> +
>
> And to save another email:
>
> >> + if (WARN_ON(!area || area->pages))
> > Is it: if (WARN_ON(!area || !area->pages))
> >> + return -ENXIO;
>
> You're absolutely right, thanks. I've got a couple more bugfixes in
> progress too, so I'll try to get an updated branch pushed out soon; I'll
> hold off posting a v3 to the list until after the upcoming merge window,
> though.
>
> Robin.
>
> [1]:http://thread.gmane.org/gmane.linux.kernel/1932343
>
next prev parent reply other threads:[~2015-06-19 1:06 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-11 15:54 [PATCH v2 0/4] arm64: IOMMU-backed DMA mapping Robin Murphy
2015-06-11 15:54 ` Robin Murphy
[not found] ` <cover.1434036796.git.robin.murphy-5wv7dgnIgG8@public.gmane.org>
2015-06-11 15:54 ` [PATCH v2 1/4] iommu/iova: Avoid over-allocating when size-aligned Robin Murphy
2015-06-11 15:54 ` Robin Murphy
2015-06-11 15:54 ` [PATCH v2 2/4] iommu: Implement common IOMMU ops for DMA mapping Robin Murphy
2015-06-11 15:54 ` Robin Murphy
[not found] ` <bf63d80c36533aa4dcc401b5a4b312ba00237e1c.1434036796.git.robin.murphy-5wv7dgnIgG8@public.gmane.org>
2015-06-18 15:00 ` Yong Wu
2015-06-18 15:00 ` Yong Wu
2015-06-18 16:54 ` Robin Murphy
2015-06-18 16:54 ` Robin Murphy
[not found] ` <5582F7C5.8060901-5wv7dgnIgG8@public.gmane.org>
2015-06-19 1:06 ` Yong Wu [this message]
2015-06-19 1:06 ` Yong Wu
2015-07-03 9:27 ` Yong Wu
2015-07-03 9:27 ` Yong Wu
2015-07-03 16:44 ` Robin Murphy
2015-07-03 16:44 ` Robin Murphy
[not found] ` <5596BBD3.1040708-5wv7dgnIgG8@public.gmane.org>
2015-07-07 7:37 ` Yong Wu
2015-07-07 7:37 ` Yong Wu
2015-06-11 15:54 ` [PATCH v2 3/4] arm64: Add IOMMU dma_ops Robin Murphy
2015-06-11 15:54 ` Robin Murphy
[not found] ` <4e298538ccedbe6f593d8edc40eb3a08ad9e4df5.1434036796.git.robin.murphy-5wv7dgnIgG8@public.gmane.org>
2015-06-18 15:00 ` Yong Wu
2015-06-18 15:00 ` Yong Wu
2015-06-11 15:54 ` [PATCH v2 4/4] arm64: Hook up " Robin Murphy
2015-06-11 15:54 ` Robin Murphy
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