[RFC PATCH 1/7] iommu/arm-smmu-v3: Introduce smmu option PAGE0_REGS_ONLY for Silicon errata.

[linucherian@gmail.com]

From: Linu Cherian <linu.cherian@cavium.com>

Cavium 99xx SMMU implementation doesn't support page 1 register space
and PAGE0_REGS_ONLY option will be enabled as an errata workaround.

This option when turned on, replaces all page 1 offsets used for
EVTQ_PROD/CONS, PRIQ_PROD/CONS register access with page 0 offsets.

Signed-off-by: Linu Cherian <linu.cherian@cavium.com>
---
 drivers/iommu/arm-smmu-v3.c | 44 ++++++++++++++++++++++++++++++++------------
 1 file changed, 32 insertions(+), 12 deletions(-)

diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index 05b4592..df9f27b 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -176,15 +176,15 @@
 #define ARM_SMMU_CMDQ_CONS		0x9c
 
 #define ARM_SMMU_EVTQ_BASE		0xa0
-#define ARM_SMMU_EVTQ_PROD		0x100a8
-#define ARM_SMMU_EVTQ_CONS		0x100ac
+#define ARM_SMMU_EVTQ_PROD(s)	        (page1_offset_adjust(0x100a8, s))
+#define ARM_SMMU_EVTQ_CONS(s)		(page1_offset_adjust(0x100ac, s))
 #define ARM_SMMU_EVTQ_IRQ_CFG0		0xb0
 #define ARM_SMMU_EVTQ_IRQ_CFG1		0xb8
 #define ARM_SMMU_EVTQ_IRQ_CFG2		0xbc
 
 #define ARM_SMMU_PRIQ_BASE		0xc0
-#define ARM_SMMU_PRIQ_PROD		0x100c8
-#define ARM_SMMU_PRIQ_CONS		0x100cc
+#define ARM_SMMU_PRIQ_PROD(s)		(page1_offset_adjust(0x100c8, s))
+#define ARM_SMMU_PRIQ_CONS(s)		(page1_offset_adjust(0x100cc, s))
 #define ARM_SMMU_PRIQ_IRQ_CFG0		0xd0
 #define ARM_SMMU_PRIQ_IRQ_CFG1		0xd8
 #define ARM_SMMU_PRIQ_IRQ_CFG2		0xdc
@@ -412,6 +412,9 @@
 #define MSI_IOVA_BASE			0x8000000
 #define MSI_IOVA_LENGTH			0x100000
 
+#define ARM_SMMU_PAGE0_REGS_ONLY(s)		\
+	((s)->options & ARM_SMMU_OPT_PAGE0_REGS_ONLY)
+
 static bool disable_bypass;
 module_param_named(disable_bypass, disable_bypass, bool, S_IRUGO);
 MODULE_PARM_DESC(disable_bypass,
@@ -597,6 +600,7 @@ struct arm_smmu_device {
 	u32				features;
 
 #define ARM_SMMU_OPT_SKIP_PREFETCH	(1 << 0)
+#define ARM_SMMU_OPT_PAGE0_REGS_ONLY    (1 << 1)
 	u32				options;
 
 	struct arm_smmu_cmdq		cmdq;
@@ -663,9 +667,19 @@ struct arm_smmu_option_prop {
 
 static struct arm_smmu_option_prop arm_smmu_options[] = {
 	{ ARM_SMMU_OPT_SKIP_PREFETCH, "hisilicon,broken-prefetch-cmd" },
+	{ ARM_SMMU_OPT_PAGE0_REGS_ONLY, "cavium-cn99xx,broken-page1-regspace"},
 	{ 0, NULL},
 };
 
+static inline unsigned long page1_offset_adjust(
+	unsigned long off, struct arm_smmu_device *smmu)
+{
+	if (!ARM_SMMU_PAGE0_REGS_ONLY(smmu))
+		return off;
+	else
+		return (off - SZ_64K);
+}
+
 static struct arm_smmu_domain *to_smmu_domain(struct iommu_domain *dom)
 {
 	return container_of(dom, struct arm_smmu_domain, domain);
@@ -1983,8 +1997,10 @@ static int arm_smmu_init_queues(struct arm_smmu_device *smmu)
 		return ret;
 
 	/* evtq */
-	ret = arm_smmu_init_one_queue(smmu, &smmu->evtq.q, ARM_SMMU_EVTQ_PROD,
-				      ARM_SMMU_EVTQ_CONS, EVTQ_ENT_DWORDS);
+	ret = arm_smmu_init_one_queue(smmu, &smmu->evtq.q,
+				      ARM_SMMU_EVTQ_PROD(smmu),
+				      ARM_SMMU_EVTQ_CONS(smmu),
+				      EVTQ_ENT_DWORDS);
 	if (ret)
 		return ret;
 
@@ -1992,8 +2008,10 @@ static int arm_smmu_init_queues(struct arm_smmu_device *smmu)
 	if (!(smmu->features & ARM_SMMU_FEAT_PRI))
 		return 0;
 
-	return arm_smmu_init_one_queue(smmu, &smmu->priq.q, ARM_SMMU_PRIQ_PROD,
-				       ARM_SMMU_PRIQ_CONS, PRIQ_ENT_DWORDS);
+	return arm_smmu_init_one_queue(smmu, &smmu->priq.q,
+				       ARM_SMMU_PRIQ_PROD(smmu),
+				       ARM_SMMU_PRIQ_CONS(smmu),
+				       PRIQ_ENT_DWORDS);
 }
 
 static int arm_smmu_init_l1_strtab(struct arm_smmu_device *smmu)
@@ -2360,8 +2378,10 @@ static int arm_smmu_device_reset(struct arm_smmu_device *smmu, bool bypass)
 
 	/* Event queue */
 	writeq_relaxed(smmu->evtq.q.q_base, smmu->base + ARM_SMMU_EVTQ_BASE);
-	writel_relaxed(smmu->evtq.q.prod, smmu->base + ARM_SMMU_EVTQ_PROD);
-	writel_relaxed(smmu->evtq.q.cons, smmu->base + ARM_SMMU_EVTQ_CONS);
+	writel_relaxed(smmu->evtq.q.prod, smmu->base +
+		       ARM_SMMU_EVTQ_PROD(smmu));
+	writel_relaxed(smmu->evtq.q.cons, smmu->base +
+		       ARM_SMMU_EVTQ_CONS(smmu));
 
 	enables |= CR0_EVTQEN;
 	ret = arm_smmu_write_reg_sync(smmu, enables, ARM_SMMU_CR0,
@@ -2376,9 +2396,9 @@ static int arm_smmu_device_reset(struct arm_smmu_device *smmu, bool bypass)
 		writeq_relaxed(smmu->priq.q.q_base,
 			       smmu->base + ARM_SMMU_PRIQ_BASE);
 		writel_relaxed(smmu->priq.q.prod,
-			       smmu->base + ARM_SMMU_PRIQ_PROD);
+			       smmu->base + ARM_SMMU_PRIQ_PROD(smmu));
 		writel_relaxed(smmu->priq.q.cons,
-			       smmu->base + ARM_SMMU_PRIQ_CONS);
+			       smmu->base + ARM_SMMU_PRIQ_CONS(smmu));
 
 		enables |= CR0_PRIQEN;
 		ret = arm_smmu_write_reg_sync(smmu, enables, ARM_SMMU_CR0,
-- 
1.9.1