linux-kernel - [PATCH 06/19] AMD IOMMU: refactor completion wait handling into separate functions

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Date:	Thu, 4 Dec 2008 18:31:43 +0100
From:	Joerg Roedel <joerg.roedel@....com>
To:	avi@...hat.com, mingo@...hat.com, dwmw2@...radead.org,
	gregkh@...e.de, weidong.han@...el.com
CC:	iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
	kvm@...r.kernel.org, Joerg Roedel <joerg.roedel@....com>
Subject: [PATCH 06/19] 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@....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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