[PATCH 2/9] iommu/arm-smmu: Calculate SMMU_CB_BASE from smmu register values

[Andreas Herrmann]

Currently it is derived from smmu resource size.  In case of a
mismatchin between the two calculations trust DT more than register
values and overwrite cb_base.

Signed-off-by: Andreas Herrmann <andreas.herrmann at calxeda.com>
---
 drivers/iommu/arm-smmu.c |   17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 6808577..4307fbc 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -207,7 +207,7 @@
 #define CBA2R_RW64_64BIT		(1 << 0)
 
 /* Translation context bank */
-#define ARM_SMMU_CB_BASE(smmu)		((smmu)->base + ((smmu)->size >> 1))
+#define ARM_SMMU_CB_BASE(smmu)		((smmu)->cb_base)
 #define ARM_SMMU_CB(smmu, n)		((n) * (smmu)->pagesize)
 
 #define ARM_SMMU_CB_SCTLR		0x0
@@ -339,6 +339,7 @@ struct arm_smmu_device {
 	struct device_node		*parent_of_node;
 
 	void __iomem			*base;
+	void __iomem			*cb_base;
 	unsigned long			size;
 	unsigned long			pagesize;
 
@@ -1622,6 +1623,7 @@ static int arm_smmu_device_cfg_probe(struct arm_smmu_device *smmu)
 	unsigned long size;
 	void __iomem *gr0_base = ARM_SMMU_GR0(smmu);
 	u32 id;
+	unsigned long t;
 
 	dev_notice(smmu->dev, "probing hardware configuration...\n");
 
@@ -1702,12 +1704,23 @@ static int arm_smmu_device_cfg_probe(struct arm_smmu_device *smmu)
 
 	/* Check that we ioremapped enough */
 	size = 1 << (((id >> ID1_NUMPAGENDXB_SHIFT) & ID1_NUMPAGENDXB_MASK) + 1);
-	size *= (smmu->pagesize << 1);
+	size *= smmu->pagesize;
+	smmu->cb_base = smmu->base + size;
+	size *= 2;
+
 	if (smmu->size < size)
 		dev_warn(smmu->dev,
 			 "device is 0x%lx bytes but only mapped 0x%lx!\n",
 			 size, smmu->size);
 
+	t = (unsigned long) smmu->base + (smmu->size >> 1);
+	if ((unsigned long)smmu->cb_base != t) {
+		dev_warn(smmu->dev, "address space mismatch, "
+			"overwriting cb_base (old: 0x%lx, new: 0x%lx)\n",
+			(unsigned long) smmu->cb_base, t);
+		smmu->cb_base = (void *) t;
+	}
+
 	smmu->num_s2_context_banks = (id >> ID1_NUMS2CB_SHIFT) &
 				      ID1_NUMS2CB_MASK;
 	smmu->num_context_banks = (id >> ID1_NUMCB_SHIFT) & ID1_NUMCB_MASK;
-- 
1.7.9.5