msm: mdss: add iommu attach in bus bandwidth control request

Add mdss_iommu_attach in mdss_bus_bandwidth_ctrl to
attach iommu on bus bandwidth enable request.
mdss_iommu_attach/mdss_iommu_dettach can happen in
separate thread, which may lead to a race condition
where attach/detach may happen at same time. Add lock
to properly synchronize the iommu attach/detach to
fix race condition.

Change-Id: I45c8ef1fa1fa1c2da9c6c3702bd007856e469b9d
Signed-off-by: Pawan Kumar <pavaku@codeaurora.org>

3 files changed, 14 insertions, 1 deletions

diff --git a/drivers/video/fbdev/msm/mdss.h b/drivers/video/fbdev/msm/mdss.h
index fc394f70c967..9bda5f0e568d 100644
--- a/drivers/video/fbdev/msm/mdss.h
+++ b/drivers/video/fbdev/msm/mdss.h
@@ -189,6 +189,8 @@ struct mdss_data_type {
 	bool mixer_switched;
 	struct mdss_panel_cfg pan_cfg;
 	struct mdss_prefill_data prefill_data;
+
+	int handoff_pending;
 };
 extern struct mdss_data_type *mdss_res;
 
diff --git a/drivers/video/fbdev/msm/mdss_mdp.c b/drivers/video/fbdev/msm/mdss_mdp.c
index 70f06802dc50..7043281575ff 100644
--- a/drivers/video/fbdev/msm/mdss_mdp.c
+++ b/drivers/video/fbdev/msm/mdss_mdp.c
@@ -83,6 +83,7 @@ struct msm_mdp_interface mdp5 = {
 static DEFINE_SPINLOCK(mdp_lock);
 static DEFINE_MUTEX(mdp_clk_lock);
 static DEFINE_MUTEX(bus_bw_lock);
+static DEFINE_MUTEX(mdp_iommu_lock);
 
 static struct mdss_panel_intf pan_types[] = {
 	{"dsi", MDSS_PANEL_INTF_DSI},
@@ -695,6 +696,8 @@ void mdss_bus_bandwidth_ctrl(int enable)
 			pm_runtime_get_sync(&mdata->pdev->dev);
 			msm_bus_scale_client_update_request(
 				mdata->bus_hdl, mdata->curr_bw_uc_idx);
+			if (!mdata->handoff_pending)
+				mdss_iommu_attach(mdata);
 		}
 	}
 
@@ -827,8 +830,10 @@ int mdss_iommu_attach(struct mdss_data_type *mdata)
 	struct mdss_iommu_map_type *iomap;
 	int i;
 
+	mutex_lock(&mdp_iommu_lock);
 	if (mdata->iommu_attached) {
 		pr_debug("mdp iommu already attached\n");
+		mutex_unlock(&mdp_iommu_lock);
 		return 0;
 	}
 
@@ -845,6 +850,7 @@ int mdss_iommu_attach(struct mdss_data_type *mdata)
 	}
 
 	mdata->iommu_attached = true;
+	mutex_unlock(&mdp_iommu_lock);
 
 	return 0;
 }
@@ -855,8 +861,10 @@ int mdss_iommu_dettach(struct mdss_data_type *mdata)
 	struct mdss_iommu_map_type *iomap;
 	int i;
 
+	mutex_lock(&mdp_iommu_lock);
 	if (!mdata->iommu_attached) {
 		pr_debug("mdp iommu already dettached\n");
+		mutex_unlock(&mdp_iommu_lock);
 		return 0;
 	}
 
@@ -873,6 +881,7 @@ int mdss_iommu_dettach(struct mdss_data_type *mdata)
 	}
 
 	mdata->iommu_attached = false;
+	mutex_unlock(&mdp_iommu_lock);
 
 	return 0;
 }
@@ -1093,6 +1102,7 @@ void mdss_mdp_footswitch_ctrl_splash(int on)
 	if (mdata != NULL) {
 		if (on) {
 			pr_debug("Enable MDP FS for splash.\n");
+			mdata->handoff_pending = true;
 			ret = regulator_enable(mdata->fs);
 			if (ret)
 				pr_err("Footswitch failed to enable\n");
@@ -1100,6 +1110,7 @@ void mdss_mdp_footswitch_ctrl_splash(int on)
 		} else {
 			pr_debug("Disable MDP FS for splash.\n");
 			regulator_disable(mdata->fs);
+			mdata->handoff_pending = false;
 		}
 	} else {
 		pr_warn("mdss mdata not initialized\n");
diff --git a/drivers/video/fbdev/msm/mdss_mdp_overlay.c b/drivers/video/fbdev/msm/mdss_mdp_overlay.c
index ebe0b41eacad..e0f109800549 100644
--- a/drivers/video/fbdev/msm/mdss_mdp_overlay.c
+++ b/drivers/video/fbdev/msm/mdss_mdp_overlay.c
@@ -2617,8 +2617,8 @@ int mdss_panel_register_done(struct mdss_panel_data *pdata)
 	 * increasing ref_cnt to help balance clocks once done.
 	 */
 	if (pdata->panel_info.cont_splash_enabled) {
-		mdss_mdp_clk_ctrl(MDP_BLOCK_POWER_ON, false);
 		mdss_mdp_footswitch_ctrl_splash(1);
+		mdss_mdp_clk_ctrl(MDP_BLOCK_POWER_ON, false);
 	}
 	return 0;
 }