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Subject[PATCH 06/19] AMD IOMMU: refactor completion wait handling into separate functions
Date
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>
---
arch/x86/kernel/amd_iommu.c | 67 +++++++++++++++++++++++++++++--------------
1 files changed, 45 insertions(+), 22 deletions(-)
diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index b774638..ac801f1 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -193,31 +193,14 @@ static int iommu_queue_command(struct amd_iommu *iommu, struct iommu_cmd *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
- * us about that by writing a value to a physical address we pass with
- * the command.
+ * This function waits until an IOMMU has completed a completion
+ * wait command
*/
-static int iommu_completion_wait(struct amd_iommu *iommu)
+static void __iommu_wait_for_completion(struct amd_iommu *iommu)
{
- int ret = 0, ready = 0;
+ int 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);
-
- iommu->need_sync = 0;
-
- spin_lock_irqsave(&iommu->lock, flags);
-
- ret = __iommu_queue_command(iommu, &cmd);
-
- if (ret)
- goto out;
+ unsigned long i = 0;

while (!ready && (i < EXIT_LOOP_COUNT)) {
++i;
@@ -232,6 +215,46 @@ static int iommu_completion_wait(struct amd_iommu *iommu)

if (unlikely((i == EXIT_LOOP_COUNT) && printk_ratelimit()))
printk(KERN_WARNING "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
+ * us about that by writing a value to a physical address we pass with
+ * the command.
+ */
+static int iommu_completion_wait(struct amd_iommu *iommu)
+{
+ int ret;
+ unsigned long flags;
+
+ iommu->need_sync = 0;
+
+ spin_lock_irqsave(&iommu->lock, flags);
+
+ ret = __iommu_completion_wait(iommu);
+
+ if (ret)
+ goto out;
+
+ __iommu_wait_for_completion(iommu);
out:
spin_unlock_irqrestore(&iommu->lock, flags);

--
1.5.6.4



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