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

Robin Murphy
2020-08-20T16:58:22Z

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@arm.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@arm.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
>>
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