After commit f1ad5338a4d5 ("of: Fix "dma-ranges" handling for bus
controllers"), the dma-ranges is not allowed for dts leaf node.
but we still would like to separate to different masters
into different iova regions.

Thus we have to separate it by the HW larbid and portid. For example,
larb1/2 are in region2 and larb3 is in region3. The problem is that
some ports inside a larb are in region4 while some ports inside this
larb are in region5. Therefore I define a "iova_region_larb_msk" to help
record the information for each a port. Take a example for a larb:
 [1] = ~0: means all ports in this larb are in region1;
 [2] = BIT(3) | BIT(4): means port3/4 in this larb are region2;
 [3] = ~(BIT(3) | BIT(4)): means all the other ports except port3/4
                           in this larb are region3.

This method also avoids the users forget/abuse the iova regions.

Signed-off-by: Yong Wu <yong.wu@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
---
 drivers/iommu/mtk_iommu.c | 45 ++++++++++++++++++++++-----------------
 1 file changed, 26 insertions(+), 19 deletions(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index aa4bdcb65ea7..bc936709fbe6 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -8,7 +8,6 @@
 #include <linux/clk.h>
 #include <linux/component.h>
 #include <linux/device.h>
-#include <linux/dma-direct.h>
 #include <linux/err.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
@@ -212,6 +211,15 @@ struct mtk_iommu_plat_data {
 	struct {
 		unsigned int	iova_region_nr;
 		const struct mtk_iommu_iova_region	*iova_region;
+		/*
+		 * Indicate the correspondance between larbs, ports and regions.
+		 *
+		 * The index is the same as iova_region and larb port numbers are
+		 * described as bit positions.
+		 * For example, storing BIT(0) at index 2,1 means "larb 1, port0 is in region 2".
+		 *              [2] = { [1] = BIT(0) }
+		 */
+		const u32	(*iova_region_larb_msk)[MTK_LARB_NR_MAX];
 	};
 
 	/*
@@ -529,30 +537,29 @@ static unsigned int mtk_iommu_get_bank_id(struct device *dev,
 static int mtk_iommu_get_iova_region_id(struct device *dev,
 					const struct mtk_iommu_plat_data *plat_data)
 {
-	const struct mtk_iommu_iova_region *rgn = plat_data->iova_region;
-	const struct bus_dma_region *dma_rgn = dev->dma_range_map;
-	int i, candidate = -1;
-	dma_addr_t dma_end;
+	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
+	unsigned int portidmsk = 0, larbid;
+	const u32 *rgn_larb_msk;
+	int i;
 
-	if (!dma_rgn || plat_data->iova_region_nr == 1)
+	if (plat_data->iova_region_nr == 1)
 		return 0;
 
-	dma_end = dma_rgn->dma_start + dma_rgn->size - 1;
-	for (i = 0; i < plat_data->iova_region_nr; i++, rgn++) {
-		/* Best fit. */
-		if (dma_rgn->dma_start == rgn->iova_base &&
-		    dma_end == rgn->iova_base + rgn->size - 1)
+	larbid = MTK_M4U_TO_LARB(fwspec->ids[0]);
+	for (i = 0; i < fwspec->num_ids; i++)
+		portidmsk |= BIT(MTK_M4U_TO_PORT(fwspec->ids[i]));
+
+	for (i = 0; i < plat_data->iova_region_nr; i++) {
+		rgn_larb_msk = plat_data->iova_region_larb_msk[i];
+		if (!rgn_larb_msk)
+			continue;
+
+		if ((rgn_larb_msk[larbid] & portidmsk) == portidmsk)
 			return i;
-		/* ok if it is inside this region. */
-		if (dma_rgn->dma_start >= rgn->iova_base &&
-		    dma_end < rgn->iova_base + rgn->size)
-			candidate = i;
 	}
 
-	if (candidate >= 0)
-		return candidate;
-	dev_err(dev, "Can NOT find the iommu domain id(%pad 0x%llx).\n",
-		&dma_rgn->dma_start, dma_rgn->size);
+	dev_err(dev, "Can NOT find the region for larb(%d-%x).\n",
+		larbid, portidmsk);
 	return -EINVAL;
 }
 
-- 
2.25.1