x86, AMD IOMMU: add mapping functions for coherent mappings

This patch adds the dma_ops functions for coherent mappings.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Cc: iommu@lists.linux-foundation.org
Cc: bhavna.sarathy@amd.com
Cc: Sebastian.Biemueller@amd.com
Cc: robert.richter@amd.com
Cc: joro@8bytes.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/amd_iommu.c

@@ -798,3 +798,77 @@ static void unmap_sg(struct device *dev, struct scatterlist *sglist,
 	spin_unlock_irqrestore(&domain->lock, flags);
 }
 
+static void *alloc_coherent(struct device *dev, size_t size,
+			    dma_addr_t *dma_addr, gfp_t flag)
+{
+	unsigned long flags;
+	void *virt_addr;
+	struct amd_iommu *iommu;
+	struct protection_domain *domain;
+	u16 devid;
+	phys_addr_t paddr;
+
+	virt_addr = (void *)__get_free_pages(flag, get_order(size));
+	if (!virt_addr)
+		return 0;
+
+	memset(virt_addr, 0, size);
+	paddr = virt_to_phys(virt_addr);
+
+	get_device_resources(dev, &iommu, &domain, &devid);
+
+	if (!iommu || !domain) {
+		*dma_addr = (dma_addr_t)paddr;
+		return virt_addr;
+	}
+
+	spin_lock_irqsave(&domain->lock, flags);
+
+	*dma_addr = __map_single(dev, iommu, domain->priv, paddr,
+				 size, DMA_BIDIRECTIONAL);
+
+	if (*dma_addr == bad_dma_address) {
+		free_pages((unsigned long)virt_addr, get_order(size));
+		virt_addr = NULL;
+		goto out;
+	}
+
+	if (iommu_has_npcache(iommu))
+		iommu_flush_pages(iommu, domain->id, *dma_addr, size);
+
+	if (iommu->need_sync)
+		iommu_completion_wait(iommu);
+
+out:
+	spin_unlock_irqrestore(&domain->lock, flags);
+
+	return virt_addr;
+}
+
+static void free_coherent(struct device *dev, size_t size,
+			  void *virt_addr, dma_addr_t dma_addr)
+{
+	unsigned long flags;
+	struct amd_iommu *iommu;
+	struct protection_domain *domain;
+	u16 devid;
+
+	get_device_resources(dev, &iommu, &domain, &devid);
+
+	if (!iommu || !domain)
+		goto free_mem;
+
+	spin_lock_irqsave(&domain->lock, flags);
+
+	__unmap_single(iommu, domain->priv, dma_addr, size, DMA_BIDIRECTIONAL);
+	iommu_flush_pages(iommu, domain->id, dma_addr, size);
+
+	if (iommu->need_sync)
+		iommu_completion_wait(iommu);
+
+	spin_unlock_irqrestore(&domain->lock, flags);
+
+free_mem:
+	free_pages((unsigned long)virt_addr, get_order(size));
+}
+