AMD IOMMU: refactor completion wait handling into separate functions

Impact: split one function into three

The separate functions are required synchronize commands across all
hardware IOMMUs in the system.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

1 files changed, 45 insertions, 23 deletions

diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index 0922d5fe633c..2280ef86651f 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -196,6 +196,46 @@ static int iommu_queue_command(struct amd_iommu *iommu, struct iommu_cmd *cmd)
 }
 
 /*
+ * This function waits until an IOMMU has completed a completion
+ * wait command
+ */
+static void __iommu_wait_for_completion(struct amd_iommu *iommu)
+{
+        int ready = 0;
+        unsigned status = 0;
+        unsigned long i = 0;
+
+        while (!ready && (i < EXIT_LOOP_COUNT)) {
+                ++i;
+                /* wait for the bit to become one */
+                status = readl(iommu->mmio_base + MMIO_STATUS_OFFSET);
+                ready = status & MMIO_STATUS_COM_WAIT_INT_MASK;
+        }
+
+        /* set bit back to zero */
+        status &= ~MMIO_STATUS_COM_WAIT_INT_MASK;
+        writel(status, iommu->mmio_base + MMIO_STATUS_OFFSET);
+
+        if (unlikely(i == EXIT_LOOP_COUNT))
+                panic("AMD IOMMU: Completion wait loop failed\n");
+}
+
+/*
+ * This function queues a completion wait command into the command
+ * buffer of an IOMMU
+ */
+static int __iommu_completion_wait(struct amd_iommu *iommu)
+{
+        struct iommu_cmd cmd;
+
+         memset(&cmd, 0, sizeof(cmd));
+         cmd.data[0] = CMD_COMPL_WAIT_INT_MASK;
+         CMD_SET_TYPE(&cmd, CMD_COMPL_WAIT);
+
+         return __iommu_queue_command(iommu, &cmd);
+}
+
+/*
  * This function is called whenever we need to ensure that the IOMMU has
  * completed execution of all commands we sent. It sends a
  * COMPLETION_WAIT command and waits for it to finish. The IOMMU informs
@@ -204,40 +244,22 @@ static int iommu_queue_command(struct amd_iommu *iommu, struct iommu_cmd *cmd)
  */
 static int iommu_completion_wait(struct amd_iommu *iommu)
 {
-        int ret = 0, ready = 0;
-        unsigned status = 0;
-        struct iommu_cmd cmd;
-        unsigned long flags, i = 0;
-
-        memset(&cmd, 0, sizeof(cmd));
-        cmd.data[0] = CMD_COMPL_WAIT_INT_MASK;
-        CMD_SET_TYPE(&cmd, CMD_COMPL_WAIT);
+        int ret = 0;
+        unsigned long flags;
 
         spin_lock_irqsave(&iommu->lock, flags);
 
         if (!iommu->need_sync)
                 goto out;
 
-        iommu->need_sync = 0;
+        ret = __iommu_completion_wait(iommu);
 
-        ret = __iommu_queue_command(iommu, &cmd);
+        iommu->need_sync = 0;
 
         if (ret)
                 goto out;
 
-        while (!ready && (i < EXIT_LOOP_COUNT)) {
-                ++i;
-                /* wait for the bit to become one */
-                status = readl(iommu->mmio_base + MMIO_STATUS_OFFSET);
-                ready = status & MMIO_STATUS_COM_WAIT_INT_MASK;
-        }
-
-        /* set bit back to zero */
-        status &= ~MMIO_STATUS_COM_WAIT_INT_MASK;
-        writel(status, iommu->mmio_base + MMIO_STATUS_OFFSET);
-
-        if (unlikely(i == EXIT_LOOP_COUNT))
-                panic("AMD IOMMU: Completion wait loop failed\n");
+        __iommu_wait_for_completion(iommu);
 
 out:
         spin_unlock_irqrestore(&iommu->lock, flags);