[PATCH v7 1/3] iommu/tegra-smmu: Use fwspec in tegra_smmu_(de)attach_dev

[Nicolin Chen <nicoleotsuka@gmail.com>]

In tegra_smmu_(de)attach_dev() functions, we poll DTB for each
client's iommus property to get swgroup ID in order to prepare
"as" and enable smmu. Actually tegra_smmu_configure() prepared
an fwspec for each client, and added to the fwspec all swgroup
IDs of client DT node in DTB.

So this patch uses fwspec in tegra_smmu_(de)attach_dev() so as
to replace the redundant DT polling code.

Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Tested-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
---

Changelog
v6->v7:
 * No change
v5->v6:
 * Added Dmitry's Reviewed-by and Tested-by
v4->v5:
 * Removed "index" and "err" assigning to 0
v3->v4:
 * Seperated the change, as a cleanup, from the rework patch
v1->v3:
 * N/A

 drivers/iommu/tegra-smmu.c | 56 ++++++++++++++++----------------------
 1 file changed, 23 insertions(+), 33 deletions(-)

diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
index 6a3ecc334481..297d49f3f80e 100644
--- a/drivers/iommu/tegra-smmu.c
+++ b/drivers/iommu/tegra-smmu.c
@@ -484,60 +484,50 @@ static void tegra_smmu_as_unprepare(struct tegra_smmu *smmu,
 static int tegra_smmu_attach_dev(struct iommu_domain *domain,
 				 struct device *dev)
 {
+	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
 	struct tegra_smmu *smmu = dev_iommu_priv_get(dev);
 	struct tegra_smmu_as *as = to_smmu_as(domain);
-	struct device_node *np = dev->of_node;
-	struct of_phandle_args args;
-	unsigned int index = 0;
-	int err = 0;
-
-	while (!of_parse_phandle_with_args(np, "iommus", "#iommu-cells", index,
-					   &args)) {
-		unsigned int swgroup = args.args[0];
-
-		if (args.np != smmu->dev->of_node) {
-			of_node_put(args.np);
-			continue;
-		}
+	unsigned int index;
+	int err;
 
-		of_node_put(args.np);
+	if (!fwspec)
+		return -ENOENT;
 
+	for (index = 0; index < fwspec->num_ids; index++) {
 		err = tegra_smmu_as_prepare(smmu, as);
-		if (err < 0)
-			return err;
+		if (err)
+			goto disable;
 
-		tegra_smmu_enable(smmu, swgroup, as->id);
-		index++;
+		tegra_smmu_enable(smmu, fwspec->ids[index], as->id);
 	}
 
 	if (index == 0)
 		return -ENODEV;
 
 	return 0;
+
+disable:
+	while (index--) {
+		tegra_smmu_disable(smmu, fwspec->ids[index], as->id);
+		tegra_smmu_as_unprepare(smmu, as);
+	}
+
+	return err;
 }
 
 static void tegra_smmu_detach_dev(struct iommu_domain *domain, struct device *dev)
 {
+	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
 	struct tegra_smmu_as *as = to_smmu_as(domain);
-	struct device_node *np = dev->of_node;
 	struct tegra_smmu *smmu = as->smmu;
-	struct of_phandle_args args;
-	unsigned int index = 0;
-
-	while (!of_parse_phandle_with_args(np, "iommus", "#iommu-cells", index,
-					   &args)) {
-		unsigned int swgroup = args.args[0];
+	unsigned int index;
 
-		if (args.np != smmu->dev->of_node) {
-			of_node_put(args.np);
-			continue;
-		}
-
-		of_node_put(args.np);
+	if (!fwspec)
+		return;
 
-		tegra_smmu_disable(smmu, swgroup, as->id);
+	for (index = 0; index < fwspec->num_ids; index++) {
+		tegra_smmu_disable(smmu, fwspec->ids[index], as->id);
 		tegra_smmu_as_unprepare(smmu, as);
-		index++;
 	}
 }
 
-- 
2.17.1