Add a mutex to protect the data in the structure mtk_iommu_data,
like ->"m4u_group" ->"m4u_dom". For the internal data, we should
protect it in ourselves driver. Add a mutex for this.
This could be a fix for the multi-groups support.

Fixes: c3045f39244e ("iommu/mediatek: Support for multi domains")
Signed-off-by: Yunfei Wang <redacted>
Signed-off-by: Yong Wu <yong.wu@mediatek.com>
---
  drivers/iommu/mtk_iommu.c | 13 +++++++++++--
  drivers/iommu/mtk_iommu.h |  2 ++
  2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index ec2c387abf60..095736bfb7b4 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c

@@ -464,15 +464,16 @@ static int mtk_iommu_attach_device(struct iommu_domain *domain,
  		dom->data = data;
  	}
  
+	mutex_lock(&data->mutex);
  	if (!data->m4u_dom) { /* Initialize the M4U HW */
  		ret = pm_runtime_resume_and_get(m4udev);
  		if (ret < 0)
-			return ret;
+			goto data_unlock;

  
  		ret = mtk_iommu_hw_init(data);
  		if (ret) {
  			pm_runtime_put(m4udev);
-			return ret;
+			goto data_unlock;
  		}
  		data->m4u_dom = dom;
  		writel(dom->cfg.arm_v7s_cfg.ttbr & MMU_PT_ADDR_MASK,

@@ -480,9 +481,14 @@ static int mtk_iommu_attach_device(struct iommu_domain *domain,
  
  		pm_runtime_put(m4udev);
  	}
+	mutex_unlock(&data->mutex);
  
  	mtk_iommu_config(data, dev, true, domid);
  	return 0;
+
+data_unlock:
+	mutex_unlock(&data->mutex);
+	return ret;
  }
  
  static void mtk_iommu_detach_device(struct iommu_domain *domain,

@@ -592,6 +598,7 @@ static struct iommu_group *mtk_iommu_device_group(struct device *dev)
  	if (domid < 0)
  		return ERR_PTR(domid);
  
+	mutex_lock(&data->mutex);
  	group = data->m4u_group[domid];
  	if (!group) {
  		group = iommu_group_alloc();

@@ -600,6 +607,7 @@ static struct iommu_group *mtk_iommu_device_group(struct device *dev)
  	} else {
  		iommu_group_ref_get(group);
  	}
+	mutex_unlock(&data->mutex);
  	return group;
  }
  

@@ -874,6 +882,7 @@ static int mtk_iommu_probe(struct platform_device *pdev)
  	}
  
  	platform_set_drvdata(pdev, data);
+	mutex_init(&data->mutex);
  
  	ret = iommu_device_sysfs_add(&data->iommu, dev, NULL,
  				     "mtk-iommu.%pa", &ioaddr);

diff --git a/drivers/iommu/mtk_iommu.h b/drivers/iommu/mtk_iommu.h
index f81fa8862ed0..f413546ac6e5 100644
--- a/drivers/iommu/mtk_iommu.h
+++ b/drivers/iommu/mtk_iommu.h

@@ -80,6 +80,8 @@ struct mtk_iommu_data {
  
  	struct dma_iommu_mapping	*mapping; /* For mtk_iommu_v1.c */
  
+	struct mutex			mutex; /* Protect m4u_group/m4u_dom above */
+
  	struct list_head		list;
  	struct mtk_smi_larb_iommu	larb_imu[MTK_LARB_NR_MAX];
  };