[PATCH v2 20/23] iommu/mediatek: Add support for multi domain

[Yong Wu <yong.wu@mediatek.com>]

Some HW IP(ex: CCU) require the special iova range. That means the
iova got from dma_alloc_attrs for that devices must locate in his
special range. In this patch, we allocate a special iova_range for
each a special requirement and create each a iommu domain for each
a iova_range.

meanwhile we still use one pagetable which support 16GB iova.

After this patch, If the iova range of a master is over 4G, the master
should:
a) Declare its special dma_ranges in its dtsi node. For example, If we
   preassign the iova 4G-8G for vcodec, then the vcodec dtsi node should
   add this:
   /*
    * iova start at 0x1_0000_0000, pa still start at 0x4000_0000
    * size is 0x1_0000_0000.
    */
   dma-ranges = <0x1 0x0 0x0 0x40000000 0x1 0x0>;  /* 4G ~ 8G */
 Note: we don't have a actual bus concept here. the master doesn't have its
 special parent node, thus this dma-ranges can only be put in the master's
 node.

b) Update the dma_mask:
  dma_set_mask_and_coherent(dev, DMA_BIT_MASK(33));

Signed-off-by: Yong Wu <yong.wu@mediatek.com>
---
 drivers/iommu/mtk_iommu.c | 47 +++++++++++++++++++++++++++++++--------
 drivers/iommu/mtk_iommu.h |  3 ++-
 2 files changed, 40 insertions(+), 10 deletions(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index 4da92e5739f3..93ce4fa806cf 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -350,6 +350,14 @@ static int mtk_iommu_domain_finalise(struct mtk_iommu_domain *dom)
 {
 	struct mtk_iommu_data *data = mtk_iommu_get_m4u_data();
 
+	/* Use the exist domain as there is only one m4u pgtable here. */
+	if (data->m4u_dom) {
+		dom->iop = data->m4u_dom->iop;
+		dom->cfg = data->m4u_dom->cfg;
+		dom->domain.pgsize_bitmap = data->m4u_dom->cfg.pgsize_bitmap;
+		return 0;
+	}
+
 	dom->cfg = (struct io_pgtable_cfg) {
 		.quirks = IO_PGTABLE_QUIRK_ARM_NS |
 			IO_PGTABLE_QUIRK_NO_PERMS |
@@ -375,6 +383,8 @@ static int mtk_iommu_domain_finalise(struct mtk_iommu_domain *dom)
 
 static struct iommu_domain *mtk_iommu_domain_alloc(unsigned type)
 {
+	struct mtk_iommu_data *data = mtk_iommu_get_m4u_data();
+	const struct mtk_iommu_iova_region *region;
 	struct mtk_iommu_domain *dom;
 
 	if (type != IOMMU_DOMAIN_DMA)
@@ -390,8 +400,9 @@ static struct iommu_domain *mtk_iommu_domain_alloc(unsigned type)
 	if (mtk_iommu_domain_finalise(dom))
 		goto  put_dma_cookie;
 
-	dom->domain.geometry.aperture_start = 0;
-	dom->domain.geometry.aperture_end = DMA_BIT_MASK(32);
+	region = data->plat_data->iova_region + data->cur_domid;
+	dom->domain.geometry.aperture_start = region->iova_base;
+	dom->domain.geometry.aperture_end = region->iova_base + region->size - 1;
 	dom->domain.geometry.force_aperture = true;
 
 	return &dom->domain;
@@ -535,19 +546,31 @@ static void mtk_iommu_release_device(struct device *dev)
 static struct iommu_group *mtk_iommu_device_group(struct device *dev)
 {
 	struct mtk_iommu_data *data = mtk_iommu_get_m4u_data();
+	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
+	struct iommu_group *group;
+	int domid;
 
 	if (!data)
 		return ERR_PTR(-ENODEV);
 
-	/* All the client devices are in the same m4u iommu-group */
-	if (!data->m4u_group) {
-		data->m4u_group = iommu_group_alloc();
-		if (IS_ERR(data->m4u_group))
+	domid = MTK_M4U_TO_DOM(fwspec->ids[0]);
+	if (domid >= data->plat_data->iova_region_nr) {
+		dev_err(dev, "iommu domain id(%d/%d) is error.\n", domid,
+			data->plat_data->iova_region_nr);
+		return ERR_PTR(-EINVAL);
+	}
+
+	group = data->m4u_group[domid];
+	if (!group) {
+		group = iommu_group_alloc();
+		if (IS_ERR(group))
 			dev_err(dev, "Failed to allocate M4U IOMMU group\n");
+		data->m4u_group[domid] = group;
 	} else {
-		iommu_group_ref_get(data->m4u_group);
+		iommu_group_ref_get(group);
 	}
-	return data->m4u_group;
+	data->cur_domid = domid;
+	return group;
 }
 
 static int mtk_iommu_of_xlate(struct device *dev, struct of_phandle_args *args)
@@ -576,14 +599,20 @@ static void mtk_iommu_get_resv_regions(struct device *dev,
 				       struct list_head *head)
 {
 	struct mtk_iommu_data *data = dev_iommu_priv_get(dev);
-	const struct mtk_iommu_iova_region *resv;
+	const struct mtk_iommu_iova_region *resv, *curdom;
 	struct iommu_resv_region *region;
 	int prot = IOMMU_WRITE | IOMMU_READ;
 	unsigned int i;
 
+	curdom = data->plat_data->iova_region + data->cur_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 in 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)
diff --git a/drivers/iommu/mtk_iommu.h b/drivers/iommu/mtk_iommu.h
index d45c13c9d324..5e346464cdf8 100644
--- a/drivers/iommu/mtk_iommu.h
+++ b/drivers/iommu/mtk_iommu.h
@@ -66,7 +66,7 @@ struct mtk_iommu_data {
 	phys_addr_t			protect_base; /* protect memory base */
 	struct mtk_iommu_suspend_reg	reg;
 	struct mtk_iommu_domain		*m4u_dom;
-	struct iommu_group		*m4u_group;
+	struct iommu_group		*m4u_group[MTK_M4U_DOM_NR_MAX];
 	bool                            enable_4GB;
 	spinlock_t			tlb_lock; /* lock for tlb range flush */
 
@@ -76,6 +76,7 @@ struct mtk_iommu_data {
 
 	struct dma_iommu_mapping	*mapping; /* For mtk_iommu_v1.c */
 
+	unsigned int			cur_domid;
 	struct list_head		list;
 	struct mtk_smi_larb_iommu	larb_imu[MTK_LARB_NR_MAX];
 };
-- 
2.18.0