On 2024/8/28 23:27, Thierry Reding wrote:
On Mon, Aug 12, 2024 at 03:10:34PM GMT, Lu Baolu wrote:
Commit <17de3f5fdd35> ("iommu: Retire bus ops") removes iommu ops from
the bus structure. The iommu subsystem no longer relies on bus for
operations. So iommu_domain_alloc() interface is no longer relevant.
Normally, iommu_paging_domain_alloc() could be a replacement for
iommu_domain_alloc() if the caller has the right device for IOMMU API
use. Unfortunately, this is not the case for this driver.
Iterate the devices on the platform bus and find a suitable device
whose device DMA is translated by an IOMMU. Then use this device to
allocate an iommu domain. The iommu subsystem prevents domains
allocated by one iommu driver from being attached to devices managed
by any different iommu driver.
Signed-off-by: Lu Baolu<baolu.lu@xxxxxxxxxxxxxxx>
Link:https://lore.kernel.org/r/20240610085555.88197-20-baolu.lu@xxxxxxxxxxxxxxx
---
drivers/gpu/drm/tegra/drm.c | 34 +++++++++++++++++++++++++---------
1 file changed, 25 insertions(+), 9 deletions(-)
Actually I think we can just do something like this:
--- >8 ---
diff --git a/drivers/gpu/drm/tegra/drm.c b/drivers/gpu/drm/tegra/drm.c
index d9f0728c3afd..d35e411d536b 100644
--- a/drivers/gpu/drm/tegra/drm.c
+++ b/drivers/gpu/drm/tegra/drm.c
@@ -1150,7 +1150,7 @@ static int host1x_drm_probe(struct host1x_device *dev)
}
if (host1x_drm_wants_iommu(dev) && iommu_present(&platform_bus_type)) {
- tegra->domain = iommu_domain_alloc(&platform_bus_type);
+ tegra->domain = iommu_paging_domain_alloc(dev->dev.parent);
if (!tegra->domain) {
err = -ENOMEM;
goto free;
--- >8 ---
That refers to the physical device that the host1x_device virtual device
was instantiated from and is a common parent to all physical devices
that are part of the virtual device.
Yes, this is really what we want. I will update the patch series later.
Thanks,
baolu
