[PATCH 1/3] gpu: host1x: Select context device based on attached IOMMU

[Mikko Perttunen]

From: Mikko Perttunen <mperttunen at nvidia.com>

On Tegra234, engines that are programmed through Host1x channels can
be attached to either the NISO0 or NISO1 SMMU. Because of that, when
selecting a context device to use with an engine, we need to select
one that is also attached to the same SMMU.

Add a parameter to host1x_memory_context_alloc to specify which device
we are allocating a context for, and use it to pick an appropriate
context device.

Signed-off-by: Mikko Perttunen <mperttunen at nvidia.com>
---
 drivers/gpu/drm/tegra/uapi.c | 2 +-
 drivers/gpu/host1x/context.c | 5 +++++
 include/linux/host1x.h       | 1 +
 3 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/tegra/uapi.c b/drivers/gpu/drm/tegra/uapi.c
index a98239cb0e29..5adab6b22916 100644
--- a/drivers/gpu/drm/tegra/uapi.c
+++ b/drivers/gpu/drm/tegra/uapi.c
@@ -116,7 +116,7 @@ int tegra_drm_ioctl_channel_open(struct drm_device *drm, void *data, struct drm_
 
 		if (supported)
 			context->memory_context = host1x_memory_context_alloc(
-				host, get_task_pid(current, PIDTYPE_TGID));
+				host, client->base.dev, get_task_pid(current, PIDTYPE_TGID));
 
 		if (IS_ERR(context->memory_context)) {
 			if (PTR_ERR(context->memory_context) != -EOPNOTSUPP) {
diff --git a/drivers/gpu/host1x/context.c b/drivers/gpu/host1x/context.c
index b08cf11f9a66..8d6447cdd882 100644
--- a/drivers/gpu/host1x/context.c
+++ b/drivers/gpu/host1x/context.c
@@ -104,6 +104,7 @@ void host1x_memory_context_list_free(struct host1x_memory_context_list *cdl)
 }
 
 struct host1x_memory_context *host1x_memory_context_alloc(struct host1x *host1x,
+							  struct device *dev,
 							  struct pid *pid)
 {
 	struct host1x_memory_context_list *cdl = &host1x->context_list;
@@ -118,6 +119,10 @@ struct host1x_memory_context *host1x_memory_context_alloc(struct host1x *host1x,
 	for (i = 0; i < cdl->len; i++) {
 		struct host1x_memory_context *cd = &cdl->devs[i];
 
+		if (cd->dev.iommu->iommu_dev != dev->iommu->iommu_dev) {
+			continue;
+		}
+
 		if (cd->owner == pid) {
 			refcount_inc(&cd->ref);
 			mutex_unlock(&cdl->lock);
diff --git a/include/linux/host1x.h b/include/linux/host1x.h
index cb2100d9b0ff..ef05de1f4f1e 100644
--- a/include/linux/host1x.h
+++ b/include/linux/host1x.h
@@ -469,6 +469,7 @@ struct host1x_memory_context {
 
 #ifdef CONFIG_IOMMU_API
 struct host1x_memory_context *host1x_memory_context_alloc(struct host1x *host1x,
+							  struct device *dev,
 							  struct pid *pid);
 void host1x_memory_context_get(struct host1x_memory_context *cd);
 void host1x_memory_context_put(struct host1x_memory_context *cd);
-- 
2.37.0