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Subject[PATCH 06/21] 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 | 65 +++++++++++++++++++++++++++++--------------
1 files changed, 44 insertions(+), 21 deletions(-)

diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index 11de0f1..db89001 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -195,6 +195,46 @@ 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) && 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
@@ -203,14 +243,8 @@ 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);

@@ -219,24 +253,13 @@ static int iommu_completion_wait(struct amd_iommu *iommu)

iommu->need_sync = 0;

- ret = __iommu_queue_command(iommu, &cmd);
+ ret = __iommu_completion_wait(iommu);

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);
+ __iommu_wait_for_completion(iommu);

- if (unlikely((i == EXIT_LOOP_COUNT) && printk_ratelimit()))
- printk(KERN_WARNING "AMD IOMMU: Completion wait loop failed\n");
out:
spin_unlock_irqrestore(&iommu->lock, flags);

--
1.5.6.4



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