introcude linux/iommu.h for an iommu api

This patch introduces the API to abstract the exported VT-d functions
for KVM into a generic API. This way the AMD IOMMU implementation can
plug into this API later.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

include/linux/iommu.h

+/*
+ * Copyright (C) 2007-2008 Advanced Micro Devices, Inc.
+ * Author: Joerg Roedel <joerg.roedel@amd.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+ */
+
+#ifndef __LINUX_IOMMU_H
+#define __LINUX_IOMMU_H
+
+#define IOMMU_READ	(1)
+#define IOMMU_WRITE	(2)
+
+struct device;
+
+struct iommu_domain {
+	void *priv;
+};
+
+struct iommu_ops {
+	int (*domain_init)(struct iommu_domain *domain);
+	void (*domain_destroy)(struct iommu_domain *domain);
+	int (*attach_dev)(struct iommu_domain *domain, struct device *dev);
+	void (*detach_dev)(struct iommu_domain *domain, struct device *dev);
+	int (*map)(struct iommu_domain *domain, unsigned long iova,
+		   phys_addr_t paddr, size_t size, int prot);
+	void (*unmap)(struct iommu_domain *domain, unsigned long iova,
+		      size_t size);
+	phys_addr_t (*iova_to_phys)(struct iommu_domain *domain,
+				    unsigned long iova);
+};
+
+#ifdef CONFIG_IOMMU_API
+
+extern void register_iommu(struct iommu_ops *ops);
+extern bool iommu_found(void);
+extern struct iommu_domain *iommu_domain_alloc(void);
+extern void iommu_domain_free(struct iommu_domain *domain);
+extern int iommu_attach_device(struct iommu_domain *domain,
+			       struct device *dev);
+extern void iommu_detach_device(struct iommu_domain *domain,
+				struct device *dev);
+extern int iommu_map_range(struct iommu_domain *domain, unsigned long iova,
+			   phys_addr_t paddr, size_t size, int prot);
+extern void iommu_unmap_range(struct iommu_domain *domain, unsigned long iova,
+			      size_t size);
+extern phys_addr_t iommu_iova_to_phys(struct iommu_domain *domain,
+				      unsigned long iova);
+
+#else /* CONFIG_IOMMU_API */
+
+static inline void register_iommu(struct iommu_ops *ops)
+{
+}
+
+static inline bool iommu_found(void)
+{
+	return false;
+}
+
+static inline struct iommu_domain *iommu_domain_alloc(void)
+{
+	return NULL;
+}
+
+static inline void iommu_domain_free(struct iommu_domain *domain)
+{
+}
+
+static inline int iommu_attach_device(struct iommu_domain *domain,
+				      struct device *dev)
+{
+	return -ENODEV;
+}
+
+static inline void iommu_detach_device(struct iommu_domain *domain,
+				       struct device *dev)
+{
+}
+
+static inline int iommu_map_range(struct iommu_domain *domain,
+				  unsigned long iova, phys_addr_t paddr,
+				  size_t size, int prot)
+{
+	return -ENODEV;
+}
+
+static inline void iommu_unmap_range(struct iommu_domain *domain,
+				     unsigned long iova, size_t size)
+{
+}
+
+static inline phys_addr_t iommu_iova_to_phys(struct iommu_domain *domain,
+					     unsigned long iova)
+{
+	return 0;
+}
+
+#endif /* CONFIG_IOMMU_API */
+
+#endif /* __LINUX_IOMMU_H */