Hello,
On 2015-02-04 08:58, Thierry Reding wrote:
From: Thierry Reding <[email protected]>
The Exynos System MMU driver unconditionally executes code and registers
a struct iommu_ops with the platform bus irrespective of whether it runs
on an Exynos SoC or not. This causes problems in multi-platform kernels
where drivers for other SoCs will no longer be able to register their
own struct iommu_ops or even try to use a struct iommu_ops for an IOMMU
that obviously isn't there.
The smallest fix I could think of is to check for the existence of any
Exynos System MMU devices in the device tree and skip initialization
otherwise.
This fixes a problem on Tegra20 where the DRM driver will try to use the
obviously non-existent Exynos System MMU.
Reported-by: Nicolas Chauvet <[email protected]>
Cc: Kukjin Kim <[email protected]>
Signed-off-by: Thierry Reding <[email protected]>
Frankly, you may mark the existing exynos iommu driver as BROKEN, what will
solve a few other issues as well. In the current version this driver is not
functional and not used on any platform. I thought that my fixes will get
into v3.20, but it looks that it won't happen.
---
drivers/iommu/exynos-iommu.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index 7ce52737c7a1..d4b41fa32368 100644
--- a/drivers/iommu/exynos-iommu.c
+++ b/drivers/iommu/exynos-iommu.c
@@ -1188,6 +1188,9 @@ static int __init exynos_iommu_init(void)
{
int ret;
+ if (!of_find_matching_node(NULL, sysmmu_of_match))
+ return 0;
+
lv2table_kmem_cache = kmem_cache_create("exynos-iommu-lv2table",
LV2TABLE_SIZE, LV2TABLE_SIZE, 0, NULL);
if (!lv2table_kmem_cache) {
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
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