[PATCH 1/5] iommu/arm-smmu: Introduce driver option handling

[Andreas Herrmann]

Introduce handling of driver options. Options are set based on DT
information when probing an SMMU device. The first option introduced
is "arm,smmu-isolate-devices". (It will be used in the bus notifier
block.)

Signed-off-by: Andreas Herrmann <andreas.herrmann at calxeda.com>
---
 drivers/iommu/arm-smmu.c |   49 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index b632bcd..b127f0f 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -348,6 +348,7 @@ struct arm_smmu_device {
 #define ARM_SMMU_FEAT_TRANS_S2		(1 << 3)
 #define ARM_SMMU_FEAT_TRANS_NESTED	(1 << 4)
 	u32				features;
+	u32				options;
 	int				version;
 
 	u32				num_context_banks;
@@ -398,6 +399,52 @@ struct arm_smmu_domain {
 static DEFINE_SPINLOCK(arm_smmu_devices_lock);
 static LIST_HEAD(arm_smmu_devices);
 
+/* driver options */
+enum arm_smmu_option {
+	ISOLATE_DEVICES = 0,
+	OPTION_MAX,
+};
+
+struct arm_smmu_option_prop {
+	enum arm_smmu_option opt;
+	const char *prop;
+};
+
+static struct arm_smmu_option_prop arm_smmu_options [] = {
+	{ ISOLATE_DEVICES, "arm,smmu-isolate-devices" },
+	{ OPTION_MAX, NULL},
+};
+
+static inline int arm_smmu_has_option(struct arm_smmu_device *smmu,
+				enum arm_smmu_option opt)
+{
+	return (smmu->options & (1 << opt));
+}
+
+static inline void arm_smmu_set_option(struct arm_smmu_device *smmu,
+				enum arm_smmu_option opt)
+{
+	smmu->options |= (1 << opt);
+}
+
+static inline void arm_smmu_clear_option(struct arm_smmu_device *smmu,
+				enum arm_smmu_option opt)
+{
+	smmu->options &= ~(1 << opt);
+}
+
+static void arm_smmu_check_options(struct arm_smmu_device *smmu)
+{
+	int i = 0;
+
+	do {
+		if (of_property_read_bool(smmu->dev->of_node,
+						arm_smmu_options[i].prop))
+			arm_smmu_set_option(smmu, arm_smmu_options[i].opt);
+		i++;
+	} while (arm_smmu_options[i].opt < OPTION_MAX);
+}
+
 static struct arm_smmu_master *find_smmu_master(struct arm_smmu_device *smmu,
 						struct device_node *dev_node)
 {
@@ -1791,6 +1838,8 @@ static int arm_smmu_device_dt_probe(struct platform_device *pdev)
 	}
 	smmu->dev = dev;
 
+	arm_smmu_check_options(smmu);
+
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (!res) {
 		dev_err(dev, "missing base address/size\n");
-- 
1.7.9.5