Hello,
On 2015-06-29 10:35, Joerg Roedel wrote:
Hi Marek,
On Thu, Jun 25, 2015 at 03:10:44PM +0200, Marek Szyprowski wrote:
+ /* skip devices which doesn't have sysmmu controller */
if (!has_sysmmu(dev))
- return -ENODEV;
+ return 0;
Thanks for reporting this! But I think that the -ENODEV return value
could be of use for the iommu core in the future. Can you please try the
attached patch, which just ignores -ENODEV as a return value from
add_device?
>From 3c9e7507e93ff6c6e05e6ee2cb123b5d35d8c412 Mon Sep 17 00:00:00 2001
From: Joerg Roedel <jroedel@xxxxxxx>
Date: Mon, 29 Jun 2015 10:16:08 +0200
Subject: [PATCH] iommu: Ignore -ENODEV errors from add_device call-back
The -ENODEV error just means that the device is not
translated by an IOMMU. We shouldn't bail out of iommu
driver initialization when that happens, as this is a common
scenario on ARM.
No returning -ENODEV in the drivers would be a bad idea, as
the IOMMU core would have no indication whether a device is
translated or not. This information is not used at the
moment, but will probably be in the future.
Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
Works fine!
Tested-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
---
drivers/iommu/iommu.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 49e7542..f286090 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -847,13 +847,24 @@ static int add_iommu_group(struct device *dev, void *data)
{
struct iommu_callback_data *cb = data;
const struct iommu_ops *ops = cb->ops;
+ int ret;
if (!ops->add_device)
return 0;
WARN_ON(dev->iommu_group);
- return ops->add_device(dev);
+ ret = ops->add_device(dev);
+
+ /*
+ * We ignore -ENODEV errors for now, as they just mean that the
+ * device is not translated by an IOMMU. We still care about
+ * other errors and fail to initialize when they happen.
+ */
+ if (ret == -ENODEV)
+ ret = 0;
+
+ return ret;
}
static int remove_iommu_group(struct device *dev, void *data)
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
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