[PATCH v9 13/16] iommu/exynos: turn on useful configuration options

[Cho KyongHo]

This turns on ACGEN and SYSSEL.

ACGEN is architectural clock gating that gates clocks by System MMU
itself if it is not active. Note that ACGEN is different from clock
gating by the CPU. ACGEN just gates clocks to the internal logic of
System MMU while clock gating by the CPU gates clocks to the System
MMU.

SYSSEL selects System MMU version in some Exynos SoCs. Some Exynos
SoCs have an option to select System MMU versions exclusively because
the SoCs adopts new System MMU version experimentally.

This also always selects LRU as TLB replacement policy. Selecting TLB
replacement policy is deprecated from System MMU 3.2. TLB in System
MMU 3.3 has single TLB replacement policy, LRU. The bit of MMU_CFG
selecting TLB replacement policy is remained as reserved.

QoS value of page table walking is set to 15 (highst value). System
MMU 3.3 can inherit QoS value of page table walking from its master
H/W's transaction. This new feature is enabled by default and QoS
value written to MMU_CFG is ignored.

Signed-off-by: Cho KyongHo <pullip.cho@xxxxxxxxxxx>
---
 drivers/iommu/exynos-iommu.c |   20 +++++++++++++++++---
 1 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index 8240f7f..9e64483 100644
--- a/drivers/iommu/exynos-iommu.c
+++ b/drivers/iommu/exynos-iommu.c
@@ -82,6 +82,11 @@
 #define CTRL_BLOCK	0x7
 #define CTRL_DISABLE	0x0
 
+#define CFG_LRU		0x1
+#define CFG_QOS(n)	((n & 0xF) << 7)
+#define CFG_MASK	0x0150FFFF /* Selecting bit 0-15, 20, 22 and 24 */
+#define CFG_ACGEN	(1 << 24) /* System MMU 3.3 only */
+#define CFG_SYSSEL	(1 << 22) /* System MMU 3.2 only */
 #define CFG_FLPDCACHE	(1 << 20) /* System MMU 3.2+ only */
 
 #define REG_MMU_CTRL		0x000
@@ -449,12 +454,21 @@ static bool __sysmmu_disable(struct sysmmu_drvdata *data)
 
 static void __sysmmu_init_config(struct sysmmu_drvdata *data, int idx)
 {
-	unsigned long cfg = 0;
+	unsigned long cfg = CFG_LRU | CFG_QOS(15);
 	int maj, min = 0;
 
 	maj = __sysmmu_version(data, idx, &min);
-	if ((maj == 3) && (min > 1))
-		cfg |= CFG_FLPDCACHE;
+	if (maj == 3) {
+		if (min >= 2) {
+			cfg |= CFG_FLPDCACHE;
+			if (min == 3) {
+				cfg |= CFG_ACGEN;
+				cfg &= ~CFG_LRU;
+			} else {
+				cfg |= CFG_SYSSEL;
+			}
+		}
+	}
 
 	__raw_writel(cfg, data->sfrbases[idx] + REG_MMU_CFG);
 }
-- 
1.7.2.5


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