iommu/exynos: remove prefetch buffer setting when enabling System MMU

Prefetch buffer must be handled accurately, exact range of a buffer,
frame by frame manually. Otherwise, it may causes page fault or
deadlock in System MMU.
Thus this patch removes prefetch buffer setting when System MMU is
initialized(enabled).

Signed-off-by: Cho KyongHo <pullip.cho@samsung.com>

diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index cfc02ed..87f6bb7 100644 (file)
--- a/drivers/iommu/exynos-iommu.c
+++ b/drivers/iommu/exynos-iommu.c
@@ -80,6 +80,8 @@
 #define CTRL_BLOCK     0x7
 #define CTRL_DISABLE   0x0
 
+#define CFG_FLPDCACHE  (1 << 20) /* System MMU 3.2+ only */
+
 #define REG_MMU_CTRL           0x000
 #define REG_MMU_CFG            0x004
 #define REG_MMU_STATUS         0x008
@@ -96,6 +98,9 @@
 
 #define REG_MMU_VERSION                0x034
 
+#define MMU_MAJ_VER(reg)       (reg >> 28)
+#define MMU_MIN_VER(reg)       ((reg >> 21) & 0x7F)
+
 #define REG_PB0_SADDR          0x04C
 #define REG_PB0_EADDR          0x050
 #define REG_PB1_SADDR          0x054
@@ -200,6 +205,22 @@ static bool is_sysmmu_active(struct sysmmu_drvdata *data)
        return data->activations > 0;
 }
 
+static unsigned int __sysmmu_version(struct sysmmu_drvdata *data,
+                                    int idx, unsigned int *minor)
+{
+       unsigned long major;
+
+       major = readl(data->sfrbases[idx] + REG_MMU_VERSION);
+
+       if (minor)
+               *minor = MMU_MIN_VER(major);
+
+       if (MMU_MAJ_VER(major) > 3)
+               return 1;
+
+       return MMU_MAJ_VER(major);
+}
+
 static void sysmmu_unblock(void __iomem *sfrbase)
 {
        __raw_writel(CTRL_ENABLE, sfrbase + REG_MMU_CTRL);
@@ -460,14 +481,15 @@ static int __exynos_sysmmu_enable(struct sysmmu_drvdata *data,
        data->pgtable = pgtable;
 
        for (i = 0; i < data->nsfrs; i++) {
+               unsigned int min;
+
                __sysmmu_set_ptbase(data->sfrbases[i], pgtable);
 
-               if ((readl(data->sfrbases[i] + REG_MMU_VERSION) >> 28) == 3) {
-                       /* System MMU version is 3.x */
-                       __raw_writel((1 << 12) | (2 << 28),
+               if ((__sysmmu_version(data, i, &min) == 3) && (min > 1)) {
+                       unsigned long cfg;
+                       cfg = __raw_readl(data->sfrbases[i] + REG_MMU_CFG);
+                       __raw_writel(cfg | CFG_FLPDCACHE,
                                        data->sfrbases[i] + REG_MMU_CFG);
-                       __sysmmu_set_prefbuf(data->sfrbases[i], 0, -1, 0);
-                       __sysmmu_set_prefbuf(data->sfrbases[i], 0, -1, 1);
                }
 
                __raw_writel(CTRL_ENABLE, data->sfrbases[i] + REG_MMU_CTRL);