iommu/mediatek: Move hw_init into attach_device

In attach device, it will update the pagetable base address register.
Move the hw_init function also here. Then it only need call
pm_runtime_get/put one time here if m4u has power domain.
Signed-off-by: Yong Wu <yong.wu@mediatek.com>
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
Link: https://lore.kernel.org/r/20210111111914.22211-17-yong.wu@mediatek.comSigned-off-by: Will Deacon <will@kernel.org>

drivers/iommu/mtk_iommu.c

@@ -126,6 +126,8 @@ struct mtk_iommu_domain {
 
 static const struct iommu_ops mtk_iommu_ops;
 
+static int mtk_iommu_hw_init(const struct mtk_iommu_data *data);
+
 /*
  * In M4U 4GB mode, the physical address is remapped as below:
  *
@@ -364,12 +366,15 @@ 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);
+	int ret;
 
 	if (!data)
 		return -ENODEV;
 
-	/* Update the pgtable base address register of the M4U HW */
-	if (!data->m4u_dom) {
+	if (!data->m4u_dom) { /* Initialize the M4U HW */
+		ret = mtk_iommu_hw_init(data);
+		if (ret)
+			return ret;
 		data->m4u_dom = dom;
 		writel(dom->cfg.arm_v7s_cfg.ttbr & MMU_PT_ADDR_MASK,
 		       data->base + REG_MMU_PT_BASE_ADDR);
@@ -724,10 +729,6 @@ static int mtk_iommu_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, data);
 
-	ret = mtk_iommu_hw_init(data);
-	if (ret)
-		return ret;
-
 	ret = iommu_device_sysfs_add(&data->iommu, dev, NULL,
 				     "mtk-iommu.%pa", &ioaddr);
 	if (ret)