iommu/shmobile: Turn the flush_lock mutex into a spinlock

The lock is taken in atomic context, replace it with a spinlock.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Joerg Roedel <joro@8bytes.org>

drivers/iommu/shmobile-ipmmu.c

@@ -35,12 +35,12 @@ void ipmmu_tlb_flush(struct shmobile_ipmmu *ipmmu)
 	if (!ipmmu)
 		return;
 
-	mutex_lock(&ipmmu->flush_lock);
+	spin_lock(&ipmmu->flush_lock);
 	if (ipmmu->tlb_enabled)
 		ipmmu_reg_write(ipmmu, IMCTR1, IMCTR1_FLUSH | IMCTR1_TLBEN);
 	else
 		ipmmu_reg_write(ipmmu, IMCTR1, IMCTR1_FLUSH);
-	mutex_unlock(&ipmmu->flush_lock);
+	spin_unlock(&ipmmu->flush_lock);
 }
 
 void ipmmu_tlb_set(struct shmobile_ipmmu *ipmmu, unsigned long phys, int size,
@@ -49,7 +49,7 @@ void ipmmu_tlb_set(struct shmobile_ipmmu *ipmmu, unsigned long phys, int size,
 	if (!ipmmu)
 		return;
 
-	mutex_lock(&ipmmu->flush_lock);
+	spin_lock(&ipmmu->flush_lock);
 	switch (size) {
 	default:
 		ipmmu->tlb_enabled = 0;
@@ -85,7 +85,7 @@ void ipmmu_tlb_set(struct shmobile_ipmmu *ipmmu, unsigned long phys, int size,
 	}
 	ipmmu_reg_write(ipmmu, IMTTBR, phys);
 	ipmmu_reg_write(ipmmu, IMASID, asid);
-	mutex_unlock(&ipmmu->flush_lock);
+	spin_unlock(&ipmmu->flush_lock);
 }
 
 static int ipmmu_probe(struct platform_device *pdev)
@@ -104,7 +104,7 @@ static int ipmmu_probe(struct platform_device *pdev)
 		dev_err(&pdev->dev, "cannot allocate device data\n");
 		return -ENOMEM;
 	}
-	mutex_init(&ipmmu->flush_lock);
+	spin_lock_init(&ipmmu->flush_lock);
 	ipmmu->dev = &pdev->dev;
 	ipmmu->ipmmu_base = devm_ioremap_nocache(&pdev->dev, res->start,
 						resource_size(res));

drivers/iommu/shmobile-ipmmu.h

@@ -14,7 +14,7 @@ struct shmobile_ipmmu {
 	struct device *dev;
 	void __iomem *ipmmu_base;
 	int tlb_enabled;
-	struct mutex flush_lock;
+	spinlock_t flush_lock;
 	const char * const *dev_names;
 	unsigned int num_dev_names;
 };