1 files changed, 19 insertions, 7 deletions

diff --git a/arch/x86/kernel/amd_iommu_init.c b/arch/x86/kernel/amd_iommu_init.c
index 238989ec077d..10b2accd12ea 100644
--- a/arch/x86/kernel/amd_iommu_init.c
+++ b/arch/x86/kernel/amd_iommu_init.c
@@ -260,6 +260,14 @@ static void iommu_enable(struct amd_iommu *iommu)
 
 static void iommu_disable(struct amd_iommu *iommu)
 {
+        /* Disable command buffer */
+        iommu_feature_disable(iommu, CONTROL_CMDBUF_EN);
+
+        /* Disable event logging and event interrupts */
+        iommu_feature_disable(iommu, CONTROL_EVT_INT_EN);
+        iommu_feature_disable(iommu, CONTROL_EVT_LOG_EN);
+
+        /* Disable IOMMU hardware itself */
         iommu_feature_disable(iommu, CONTROL_IOMMU_EN);
 }
 
@@ -478,6 +486,10 @@ static void iommu_enable_event_buffer(struct amd_iommu *iommu)
         memcpy_toio(iommu->mmio_base + MMIO_EVT_BUF_OFFSET,
                     &entry, sizeof(entry));
 
+        /* set head and tail to zero manually */
+        writel(0x00, iommu->mmio_base + MMIO_EVT_HEAD_OFFSET);
+        writel(0x00, iommu->mmio_base + MMIO_EVT_TAIL_OFFSET);
+
         iommu_feature_enable(iommu, CONTROL_EVT_LOG_EN);
 }
 
@@ -1042,6 +1054,7 @@ static void enable_iommus(void)
         struct amd_iommu *iommu;
 
         for_each_iommu(iommu) {
+                iommu_disable(iommu);
                 iommu_set_device_table(iommu);
                 iommu_enable_command_buffer(iommu);
                 iommu_enable_event_buffer(iommu);
@@ -1066,12 +1079,6 @@ static void disable_iommus(void)
 
 static int amd_iommu_resume(struct sys_device *dev)
 {
-        /*
-         * Disable IOMMUs before reprogramming the hardware registers.
-         * IOMMU is still enabled from the resume kernel.
-         */
-        disable_iommus();
-
         /* re-load the hardware */
         enable_iommus();
 
@@ -1079,8 +1086,8 @@ static int amd_iommu_resume(struct sys_device *dev)
          * we have to flush after the IOMMUs are enabled because a
          * disabled IOMMU will never execute the commands we send
          */
-        amd_iommu_flush_all_domains();
         amd_iommu_flush_all_devices();
+        amd_iommu_flush_all_domains();
 
         return 0;
 }
@@ -1273,6 +1280,11 @@ free:
         goto out;
 }
 
+void amd_iommu_shutdown(void)
+{
+        disable_iommus();
+}
+
 /****************************************************************************
  *
  * Early detect code. This code runs at IOMMU detection time in the DMA