iommu/mediatek: Add get_domain_id from dev->dma_range_map

Add a new interface _get_domain_id from dev->dma_range_map,
The iommu consumer device will use dma-ranges in dtsi node to indicate
its dma address region requirement. In this iommu driver, we will get
the requirement and decide which iova domain it should locate.

In the lastest SoC, there will be several iova-regions(domains), we will
compare and calculate which domain is right. If the start/end of device
requirement equal some region. it is best fit of course. If it is inside
some region, it is also ok. the iova requirement of a device should not
be inside two or more regions.

Signed-off-by: Yong Wu <yong.wu@mediatek.com>
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
Link: https://lore.kernel.org/r/20210111111914.22211-28-yong.wu@mediatek.com
Signed-off-by: Will Deacon <will@kernel.org>

drivers/iommu/mtk_iommu.c

@@ -8,6 +8,7 @@
 #include <linux/clk.h>
 #include <linux/component.h>
 #include <linux/device.h>
+#include <linux/dma-direct.h>
 #include <linux/dma-iommu.h>
 #include <linux/err.h>
 #include <linux/interrupt.h>
@@ -314,6 +315,36 @@ static irqreturn_t mtk_iommu_isr(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
+static int mtk_iommu_get_domain_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;
+
+	if (!dma_rgn || 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)
+			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);
+	return -EINVAL;
+}
+
 static void mtk_iommu_config(struct mtk_iommu_data *data,
 			     struct device *dev, bool enable)
 {
@@ -400,11 +431,15 @@ static int mtk_iommu_attach_device(struct iommu_domain *domain,
 	struct mtk_iommu_data *data = dev_iommu_priv_get(dev);
 	struct mtk_iommu_domain *dom = to_mtk_domain(domain);
 	struct device *m4udev = data->dev;
-	int ret;
+	int ret, domid;
 
 	if (!data)
 		return -ENODEV;
 
+	domid = mtk_iommu_get_domain_id(dev, data->plat_data);
+	if (domid < 0)
+		return domid;
+
 	if (!dom->data) {
 		if (mtk_iommu_domain_finalise(dom, data))
 			return -ENODEV;
@@ -534,10 +569,15 @@ 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();
+	int domid;
 
 	if (!data)
 		return ERR_PTR(-ENODEV);
 
+	domid = mtk_iommu_get_domain_id(dev, data->plat_data);
+	if (domid < 0)
+		return ERR_PTR(domid);
+
 	/* All the client devices are in the same m4u iommu-group */
 	if (!data->m4u_group) {
 		data->m4u_group = iommu_group_alloc();