iommu/amd: Detect pre enabled translation

Add functions to check whether translation is already enabled in IOMMU.
Signed-off-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/amd_iommu_init.c

@@ -258,6 +258,25 @@ static int amd_iommu_enable_interrupts(void);
 static int __init iommu_go_to_state(enum iommu_init_state state);
 static void init_device_table_dma(void);
 
+bool translation_pre_enabled(struct amd_iommu *iommu)
+{
+	return (iommu->flags & AMD_IOMMU_FLAG_TRANS_PRE_ENABLED);
+}
+
+static void clear_translation_pre_enabled(struct amd_iommu *iommu)
+{
+	iommu->flags &= ~AMD_IOMMU_FLAG_TRANS_PRE_ENABLED;
+}
+
+static void init_translation_status(struct amd_iommu *iommu)
+{
+	u32 ctrl;
+
+	ctrl = readl(iommu->mmio_base + MMIO_CONTROL_OFFSET);
+	if (ctrl & (1<<CONTROL_IOMMU_EN))
+		iommu->flags |= AMD_IOMMU_FLAG_TRANS_PRE_ENABLED;
+}
+
 static inline void update_last_devid(u16 devid)
 {
 	if (devid > amd_iommu_last_bdf)
@@ -1399,6 +1418,11 @@ static int __init init_iommu_one(struct amd_iommu *iommu, struct ivhd_header *h)
 
 	iommu->int_enabled = false;
 
+	init_translation_status(iommu);
+
+	if (translation_pre_enabled(iommu))
+		pr_warn("Translation is already enabled - trying to copy translation structures\n");
+
 	ret = init_iommu_from_acpi(iommu, h);
 	if (ret)
 		return ret;

drivers/iommu/amd_iommu_proto.h

@@ -87,4 +87,5 @@ static inline bool iommu_feature(struct amd_iommu *iommu, u64 f)
 	return !!(iommu->features & f);
 }
 
+extern bool translation_pre_enabled(struct amd_iommu *iommu);
 #endif /* _ASM_X86_AMD_IOMMU_PROTO_H  */

drivers/iommu/amd_iommu_types.h

@@ -435,6 +435,8 @@ struct iommu_domain;
 struct irq_domain;
 struct amd_irte_ops;
 
+#define AMD_IOMMU_FLAG_TRANS_PRE_ENABLED      (1 << 0)
+
 /*
  * This structure contains generic data for  IOMMU protection domains
  * independent of their use.
@@ -569,6 +571,7 @@ struct amd_iommu {
 	struct amd_irte_ops *irte_ops;
 #endif
 
+	u32 flags;
 	volatile u64 __aligned(8) cmd_sem;
 };