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Commit 8d201968 authored by Joerg Roedel's avatar Joerg Roedel
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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: default avatarJoerg Roedel <joerg.roedel@amd.com>
parent a2acfb75

arch/x86/kernel/amd_iommu.c

+45 −23
Original line number Diff line number Diff line
@@ -196,48 +196,70 @@ 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;

	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;

	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);



	 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 = 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);