Thread (50 messages) flat view 50 messages, 12 authors, 2020-09-28

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

From: Robin Murphy <robin.murphy@arm.com>
Date: 2020-08-20 16:58:22
Also in: dri-devel, linux-arm-msm, linux-iommu, linux-media, linux-mediatek, linux-samsung-soc, linux-tegra, lkml

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 [off-list ref] wrote:
quoted
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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