commit ff174f9f0d37217792d2701b7ae35d70e4ddb2eb
author Olav Haugan <ohaugan@codeaurora.org> Sat Aug 10 11:17:57 2013 -0700
committer Olav Haugan <ohaugan@codeaurora.org> Thu Mar 27 17:03:21 2014 -0700
tree 00f7caf7dd4effd78d7946636fc0b9f906e90745
parent 8f52386c8b3369f4d5788106c8acd23800c279ed

iommu: msm: Add reference counting to IOMMUv1

Add reference counting to IOMMU attach and detach so that clients
can attach to the same context bank which allows for sharing of
context banks among client.

Change-Id: I38293a0097ff4bba616288f0b1c384db51aeed28
Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>

drivers/iommu/msm_iommu-v1.c

diff --git a/drivers/iommu/msm_iommu-v1.c b/drivers/iommu/msm_iommu-v1.c
index 911a9e7..d0c2bbf 100644
--- a/drivers/iommu/msm_iommu-v1.c
+++ b/drivers/iommu/msm_iommu-v1.c
@@ -667,7 +667,7 @@
 	struct msm_iommu_drvdata *iommu_drvdata;
 	struct msm_iommu_ctx_drvdata *ctx_drvdata;
 	struct msm_iommu_ctx_drvdata *tmp_drvdata;
-	int ret;
+	int ret = 0;
 	int is_secure;
 
 	mutex_lock(&msm_iommu_lock);
@@ -675,41 +675,46 @@
 	priv = domain->priv;
 	if (!priv || !dev) {
 		ret = -EINVAL;
-		goto fail;
+		goto unlock;
 	}
 
 	iommu_drvdata = dev_get_drvdata(dev->parent);
 	ctx_drvdata = dev_get_drvdata(dev);
 	if (!iommu_drvdata || !ctx_drvdata) {
 		ret = -EINVAL;
-		goto fail;
+		goto unlock;
 	}
 
+	++ctx_drvdata->attach_count;
+
+	if (ctx_drvdata->attach_count > 1)
+		goto already_attached;
+
 	if (!list_empty(&ctx_drvdata->attached_elm)) {
 		ret = -EBUSY;
-		goto fail;
+		goto unlock;
 	}
 
 	list_for_each_entry(tmp_drvdata, &priv->list_attached, attached_elm)
 		if (tmp_drvdata == ctx_drvdata) {
 			ret = -EBUSY;
-			goto fail;
+			goto unlock;
 		}
 
 	is_secure = iommu_drvdata->sec_id != -1;
 
 	ret = __enable_regulators(iommu_drvdata);
 	if (ret)
-		goto fail;
+		goto unlock;
 
 	ret = apply_bus_vote(iommu_drvdata, 1);
 	if (ret)
-		goto fail;
+		goto unlock;
 
 	ret = __enable_clocks(iommu_drvdata);
 	if (ret) {
 		__disable_regulators(iommu_drvdata);
-		goto fail;
+		goto unlock;
 	}
 
 	/* We can only do this once */
@@ -724,7 +729,7 @@
 			if (ret) {
 				__disable_regulators(iommu_drvdata);
 				__disable_clocks(iommu_drvdata);
-				goto fail;
+				goto unlock;
 			}
 		}
 		program_iommu_bfb_settings(iommu_drvdata->base,
@@ -743,11 +748,12 @@
 	ctx_drvdata->attached_domain = domain;
 	++iommu_drvdata->ctx_attach_count;
 
+already_attached:
 	mutex_unlock(&msm_iommu_lock);
 
 	msm_iommu_attached(dev->parent);
 	return ret;
-fail:
+unlock:
 	mutex_unlock(&msm_iommu_lock);
 	return ret;
 }
@@ -766,16 +772,22 @@
 	mutex_lock(&msm_iommu_lock);
 	priv = domain->priv;
 	if (!priv || !dev)
-		goto fail;
+		goto unlock;
 
 	iommu_drvdata = dev_get_drvdata(dev->parent);
 	ctx_drvdata = dev_get_drvdata(dev);
 	if (!iommu_drvdata || !ctx_drvdata || !ctx_drvdata->attached_domain)
-		goto fail;
+		goto unlock;
+
+	--ctx_drvdata->attach_count;
+	BUG_ON(ctx_drvdata->attach_count < 0);
+
+	if (ctx_drvdata->attach_count > 0)
+		goto unlock;
 
 	ret = __enable_clocks(iommu_drvdata);
 	if (ret)
-		goto fail;
+		goto unlock;
 
 	is_secure = iommu_drvdata->sec_id != -1;
 
@@ -803,7 +815,7 @@
 	ctx_drvdata->attached_domain = NULL;
 	BUG_ON(iommu_drvdata->ctx_attach_count == 0);
 	--iommu_drvdata->ctx_attach_count;
-fail:
+unlock:
 	mutex_unlock(&msm_iommu_lock);
 }