iommu/mediatek: Add iova reserved function

For multiple iommu_domains, we need to reserve some iova regions. Take a
example, If the default iova region is 0 ~ 4G, but the 0x4000_0000 ~
0x43ff_ffff is only for the special CCU0 domain. Thus we should exclude
this region for the default iova region.

Signed-off-by: Anan sun <anan.sun@mediatek.com>
Signed-off-by: Chao Hao <chao.hao@mediatek.com>
Signed-off-by: Yong Wu <yong.wu@mediatek.com>
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
Link: https://lore.kernel.org/r/20210111111914.22211-30-yong.wu@mediatek.com
Signed-off-by: Will Deacon <will@kernel.org>

Author: YongWu-HF

drivers/iommu/mtk_iommu.c

@@ -626,6 +626,35 @@ static int mtk_iommu_of_xlate(struct device *dev, struct of_phandle_args *args)
 	return iommu_fwspec_add_ids(dev, args->args, 1);
 }
 
+static void mtk_iommu_get_resv_regions(struct device *dev,
+				       struct list_head *head)
+{
+	struct mtk_iommu_data *data = dev_iommu_priv_get(dev);
+	unsigned int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
+	const struct mtk_iommu_iova_region *resv, *curdom;
+	struct iommu_resv_region *region;
+	int prot = IOMMU_WRITE | IOMMU_READ;
+
+	if (domid < 0)
+		return;
+	curdom = data->plat_data->iova_region + domid;
+	for (i = 0; i < data->plat_data->iova_region_nr; i++) {
+		resv = data->plat_data->iova_region + i;
+
+		/* Only reserve when the region is inside the current domain */
+		if (resv->iova_base <= curdom->iova_base ||
+		    resv->iova_base + resv->size >= curdom->iova_base + curdom->size)
+			continue;
+
+		region = iommu_alloc_resv_region(resv->iova_base, resv->size,
+						 prot, IOMMU_RESV_RESERVED);
+		if (!region)
+			return;
+
+		list_add_tail(&region->list, head);
+	}
+}
+
 static const struct iommu_ops mtk_iommu_ops = {
 	.domain_alloc	= mtk_iommu_domain_alloc,
 	.domain_free	= mtk_iommu_domain_free,
@@ -641,6 +670,8 @@ static const struct iommu_ops mtk_iommu_ops = {
 	.release_device	= mtk_iommu_release_device,
 	.device_group	= mtk_iommu_device_group,
 	.of_xlate	= mtk_iommu_of_xlate,
+	.get_resv_regions = mtk_iommu_get_resv_regions,
+	.put_resv_regions = generic_iommu_put_resv_regions,
 	.pgsize_bitmap	= SZ_4K | SZ_64K | SZ_1M | SZ_16M,
 };