[PATCH v5 2/2] iommu/exynos: Add iommu driver for Exynos Platforms

On Thu, Oct 13, 2011 at 04:13:23AM -0400, KyongHo Cho wrote:

+struct exynos_iommu_domain {
+       struct device *dev;
+       unsigned long *pgtable;
+       spinlock_t lock;
+       spinlock_t pgtablelock;
+};

Can you please add comments to document what these spinlocks protect?

+static int exynos_iommu_attach_device(struct iommu_domain *domain,
+                                  struct device *dev)
+{
+       struct exynos_iommu_domain *priv = domain->priv;
+       int ret;
+
+       spin_lock(&priv->lock);
+
+       priv->dev = dev;
+
+       spin_unlock(&priv->lock);
+
+       ret = exynos_iommu_enable(domain);
+
+       return ret;
+}
+
+static void exynos_iommu_detach_device(struct iommu_domain *domain,
+                                   struct device *dev)
+{
+       struct exynos_iommu_domain *priv = domain->priv;
+
+       spin_lock(&priv->lock);
+
+       if (priv->dev == dev) {
+               priv->dev = NULL;
+
+               spin_unlock(&priv->lock);
+
+               exynos_iommu_disable(domain);
+       } else {
+               spin_unlock(&priv->lock);
+       }
+}

That looks weird. As I read this code there is a 1-1 mapping between a
device and a domain. This breaks semantics of the iommu-api where a
domain can contain multiple devices.


	Joerg

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