linux-kernel - Re: [PATCH 10/18] iommu/msm: Add IOMMU_DOMAIN_DMA support

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Message-ID: <b5aa001f-6a1c-af0b-1526-c5b7a2e29ef7@arm.com>
Date:   Thu, 20 Aug 2020 17:58:12 +0100
From:   Robin Murphy <robin.murphy@....com>
To:     Rob Clark <robdclark@...il.com>
Cc:     Christoph Hellwig <hch@....de>, Joerg Roedel <joro@...tes.org>,
        Russell King - ARM Linux <linux@...linux.org.uk>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        dri-devel <dri-devel@...ts.freedesktop.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Thierry Reding <thierry.reding@...il.com>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        digetx@...il.com, Suman Anna <s-anna@...com>,
        Will Deacon <will@...nel.org>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        "moderated list:ARM/S5P EXYNOS AR..." 
        <linux-samsung-soc@...r.kernel.org>,
        Magnus Damm <magnus.damm@...il.com>,
        Kyungmin Park <kyungmin.park@...sung.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Andy Gross <agross@...nel.org>, Yong Wu <yong.wu@...iatek.com>,
        linux-media@...r.kernel.org,
        linux-arm-msm <linux-arm-msm@...r.kernel.org>,
        Krishna Reddy <vdumpa@...dia.com>,
        "moderated list:ARM/Mediatek SoC..." 
        <linux-mediatek@...ts.infradead.org>, linux-tegra@...r.kernel.org,
        "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" 
        <linux-arm-kernel@...ts.infradead.org>,
        Seung-Woo Kim <sw0312.kim@...sung.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        t-kristo@...com, iommu@...ts.linux-foundation.org
Subject: Re: [PATCH 10/18] iommu/msm: Add IOMMU_DOMAIN_DMA support

On 2020-08-20 16:55, Rob Clark wrote:
> Side note, I suspect we'll end up needing something like
> 0e764a01015dfebff8a8ffd297d74663772e248a .. if someone can dig a 32b
> device out of the closet and dust it off, the fix is easy enough.
> Just wanted to mention that here so anyone with a 32b device could
> find what is needed.

FWIW there shouldn't be any material change here - the generic default 
domain is installed under the same circumstances as the Arm 
dma_iommu_mapping was, so if any platform does have an issue, then it 
should already have started 4 years with f78ebca8ff3d ("iommu/msm: Add 
support for generic master bindings").

Robin.

> 
> BR,
> -R
> 
> On Thu, Aug 20, 2020 at 8:09 AM Robin Murphy <robin.murphy@....com> wrote:
>>
>> Now that arch/arm is wired up for default domains and iommu-dma,
>> implement the corresponding driver-side support for DMA domains.
>>
>> Signed-off-by: Robin Murphy <robin.murphy@....com>
>> ---
>>   drivers/iommu/msm_iommu.c | 7 ++++++-
>>   1 file changed, 6 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/iommu/msm_iommu.c b/drivers/iommu/msm_iommu.c
>> index 3615cd6241c4..f34efcbb0b2b 100644
>> --- a/drivers/iommu/msm_iommu.c
>> +++ b/drivers/iommu/msm_iommu.c
>> @@ -8,6 +8,7 @@
>>   #include <linux/kernel.h>
>>   #include <linux/init.h>
>>   #include <linux/platform_device.h>
>> +#include <linux/dma-iommu.h>
>>   #include <linux/errno.h>
>>   #include <linux/io.h>
>>   #include <linux/io-pgtable.h>
>> @@ -314,13 +315,16 @@ static struct iommu_domain *msm_iommu_domain_alloc(unsigned type)
>>   {
>>          struct msm_priv *priv;
>>
>> -       if (type != IOMMU_DOMAIN_UNMANAGED)
>> +       if (type != IOMMU_DOMAIN_UNMANAGED && type != IOMMU_DOMAIN_DMA)
>>                  return NULL;
>>
>>          priv = kzalloc(sizeof(*priv), GFP_KERNEL);
>>          if (!priv)
>>                  goto fail_nomem;
>>
>> +       if (type == IOMMU_DOMAIN_DMA && iommu_get_dma_cookie(&priv->domain))
>> +               goto fail_nomem;
>> +
>>          INIT_LIST_HEAD(&priv->list_attached);
>>
>>          priv->domain.geometry.aperture_start = 0;
>> @@ -339,6 +343,7 @@ static void msm_iommu_domain_free(struct iommu_domain *domain)
>>          struct msm_priv *priv;
>>          unsigned long flags;
>>
>> +       iommu_put_dma_cookie(domain);
>>          spin_lock_irqsave(&msm_iommu_lock, flags);
>>          priv = to_msm_priv(domain);
>>          kfree(priv);
>> --
>> 2.28.0.dirty
>>
>> _______________________________________________
>> dri-devel mailing list
>> dri-devel@...ts.freedesktop.org
>> https://lists.freedesktop.org/mailman/listinfo/dri-devel

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