[PATCH v2 13/23] iommu/mediatek: Add device link for smi-common and m4u

[Yong Wu]

In the lastest SoC, M4U has its special power domain. thus, If the engine
begin to work, it should help enable the power for M4U firstly.
Currently if the engine work, it always enable the power/clocks for
smi-larbs/smi-common. This patch adds device_link for smi-common and M4U.
then, if smi-common power is enabled, the M4U power also is powered on
automatically.

Normally M4U connect with several smi-larbs and their smi-common always
are the same, In this patch it get smi-common dev from the first smi-larb
device(i==0), then add the device_link only while m4u has power-domain.

Signed-off-by: Yong Wu <yong.wu@xxxxxxxxxxxx>
---
 drivers/iommu/mtk_iommu.c | 33 ++++++++++++++++++++++++++++++---
 drivers/iommu/mtk_iommu.h |  1 +
 2 files changed, 31 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index 940b7a9191b2..68de59e0d521 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -20,6 +20,7 @@
 #include <linux/of_irq.h>
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <asm/barrier.h>
@@ -681,7 +682,7 @@ static int mtk_iommu_probe(struct platform_device *pdev)
 		return larb_nr;
 
 	for (i = 0; i < larb_nr; i++) {
-		struct device_node *larbnode;
+		struct device_node *larbnode, *smicomm_node;
 		struct platform_device *plarbdev;
 		u32 id;
 
@@ -707,6 +708,26 @@ static int mtk_iommu_probe(struct platform_device *pdev)
 
 		component_match_add_release(dev, &match, release_of,
 					    compare_of, larbnode);
+		if (!i) {
+			smicomm_node = of_parse_phandle(larbnode, "mediatek,smi", 0);
+			if (!smicomm_node)
+				return -EINVAL;
+
+			plarbdev = of_find_device_by_node(smicomm_node);
+			of_node_put(smicomm_node);
+			data->smicomm_dev = &plarbdev->dev;
+		}
+	}
+
+	if (dev->pm_domain) {
+		struct device_link *link;
+
+		link = device_link_add(data->smicomm_dev, dev,
+				       DL_FLAG_STATELESS | DL_FLAG_PM_RUNTIME);
+		if (!link) {
+			dev_err(dev, "Unable link %s.\n", dev_name(data->smicomm_dev));
+			return -EINVAL;
+		}
 	}
 
 	platform_set_drvdata(pdev, data);
@@ -714,14 +735,14 @@ static int mtk_iommu_probe(struct platform_device *pdev)
 	ret = iommu_device_sysfs_add(&data->iommu, dev, NULL,
 				     "mtk-iommu.%pa", &ioaddr);
 	if (ret)
-		return ret;
+		goto out;
 
 	iommu_device_set_ops(&data->iommu, &mtk_iommu_ops);
 	iommu_device_set_fwnode(&data->iommu, &pdev->dev.of_node->fwnode);
 
 	ret = iommu_device_register(&data->iommu);
 	if (ret)
-		return ret;
+		goto out;
 
 	spin_lock_init(&data->tlb_lock);
 	list_add_tail(&data->list, &m4ulist);
@@ -730,6 +751,10 @@ static int mtk_iommu_probe(struct platform_device *pdev)
 		bus_set_iommu(&platform_bus_type, &mtk_iommu_ops);
 
 	return component_master_add_with_match(dev, &mtk_iommu_com_ops, match);
+out:
+	if (dev->pm_domain)
+		device_link_remove(data->smicomm_dev, dev);
+	return ret;
 }
 
 static int mtk_iommu_remove(struct platform_device *pdev)
@@ -743,6 +768,8 @@ static int mtk_iommu_remove(struct platform_device *pdev)
 		bus_set_iommu(&platform_bus_type, NULL);
 
 	clk_disable_unprepare(data->bclk);
+	if (pdev->dev.pm_domain)
+		device_link_remove(data->smicomm_dev, &pdev->dev);
 	devm_free_irq(&pdev->dev, data->irq, data);
 	component_master_del(&pdev->dev, &mtk_iommu_com_ops);
 	return 0;
diff --git a/drivers/iommu/mtk_iommu.h b/drivers/iommu/mtk_iommu.h
index a2e2c844b96e..ae7909815cdb 100644
--- a/drivers/iommu/mtk_iommu.h
+++ b/drivers/iommu/mtk_iommu.h
@@ -67,6 +67,7 @@ struct mtk_iommu_data {
 
 	struct iommu_device		iommu;
 	const struct mtk_iommu_plat_data *plat_data;
+	struct device			*smicomm_dev;
 
 	struct dma_iommu_mapping	*mapping; /* For mtk_iommu_v1.c */
 
-- 
2.18.0