msm: mdss: avoid corner cases with DSI_INT_CTRL register read/write

To enable/disable a particular interrupt mask for DSI, we currently
read the DSI_INT_CTRL register and add/remove the interrupt mask on
top of the current register value. With this approach, we sometimes
clear some interrupts without handling them. Handle this case by
writing back only the required interrupt mask bits to the
DSI_INT_CTRL register.

Below is an instance of such issue when a DSI register read
operation is performed.

<3>[  342.509070] mdss_dsi_isr: ndx=0 isr=3200002
             -> At first, DSI error interrupt is received.

<3>[  342.512239] mdss_dsi_err_intr_ctrl: intr=1310003 enable=0
             -> During DSI_INT_CTRL read/write operation,
we clear the CMD_DMA_DONE interrupt which arrives few milli
seconds after DSI error interrupt.

<3>[  342.517620] mdss_dsi_fifo_status: status=44441000

<3>[  342.522351] mdss_dsi_timeout_status: status=1

<3>[  342.526980] mdss_dsi_err_intr_ctrl: intr=3210002 enable=1

<3>[  342.693365] mdss_dsi_cmds_rx: failed to tx cmd = 0xa
             -> This causes a CMD DMA timeout even though the
CMD_DMA_DONE interrupt arrived.

Change-Id: I82ba142d4da4ae5f4a1a2761c32b8af7964b538b
Signed-off-by: Padmanabhan Komanduru <pkomandu@codeaurora.org>

2 files changed, 8 insertions, 0 deletions

diff --git a/drivers/video/fbdev/msm/mdss_dsi.h b/drivers/video/fbdev/msm/mdss_dsi.h
index bb962ef4a7b7..54f2db5400b3 100644
--- a/drivers/video/fbdev/msm/mdss_dsi.h
+++ b/drivers/video/fbdev/msm/mdss_dsi.h
@@ -163,6 +163,8 @@ enum dsi_pm_type {
 #define DSI_INTR_CMD_MDP_DONE		BIT(8)
 #define DSI_INTR_CMD_DMA_DONE_MASK	BIT(1)
 #define DSI_INTR_CMD_DMA_DONE		BIT(0)
+/* Update this if more interrupt masks are added in future chipsets */
+#define DSI_INTR_TOTAL_MASK		0x2222AA02
 
 #define DSI_CMD_TRIGGER_NONE		0x0	/* mdp trigger */
 #define DSI_CMD_TRIGGER_TE		0x02
diff --git a/drivers/video/fbdev/msm/mdss_dsi_host.c b/drivers/video/fbdev/msm/mdss_dsi_host.c
index 7f1dae75857c..146bd524ace7 100644
--- a/drivers/video/fbdev/msm/mdss_dsi_host.c
+++ b/drivers/video/fbdev/msm/mdss_dsi_host.c
@@ -719,6 +719,7 @@ void mdss_dsi_err_intr_ctrl(struct mdss_dsi_ctrl_pdata *ctrl, u32 mask,
 	u32 intr;
 
 	intr = MIPI_INP(ctrl->ctrl_base + 0x0110);
+	intr &= DSI_INTR_TOTAL_MASK;
 
 	if (enable)
 		intr |= mask;
@@ -787,6 +788,7 @@ void mdss_dsi_restore_intr_mask(struct mdss_dsi_ctrl_pdata *ctrl)
 	u32 mask;
 
 	mask = MIPI_INP((ctrl->ctrl_base) + 0x0110);
+	mask &= DSI_INTR_TOTAL_MASK;
 	mask |= (DSI_INTR_CMD_DMA_DONE_MASK | DSI_INTR_ERROR_MASK |
 				DSI_INTR_BTA_DONE_MASK);
 	MIPI_OUTP((ctrl->ctrl_base) + 0x0110, mask);
@@ -1680,6 +1682,7 @@ void mdss_dsi_en_wait4dynamic_done(struct mdss_dsi_ctrl_pdata *ctrl)
 	u32 data;
 	/* DSI_INTL_CTRL */
 	data = MIPI_INP((ctrl->ctrl_base) + 0x0110);
+	data &= DSI_INTR_TOTAL_MASK;
 	data |= DSI_INTR_DYNAMIC_REFRESH_MASK;
 	MIPI_OUTP((ctrl->ctrl_base) + 0x0110, data);
 
@@ -1695,6 +1698,7 @@ void mdss_dsi_en_wait4dynamic_done(struct mdss_dsi_ctrl_pdata *ctrl)
 		pr_err("Dynamic interrupt timedout\n");
 
 	data = MIPI_INP((ctrl->ctrl_base) + 0x0110);
+	data &= DSI_INTR_TOTAL_MASK;
 	data &= ~DSI_INTR_DYNAMIC_REFRESH_MASK;
 	MIPI_OUTP((ctrl->ctrl_base) + 0x0110, data);
 }
@@ -1706,6 +1710,7 @@ void mdss_dsi_wait4video_done(struct mdss_dsi_ctrl_pdata *ctrl)
 
 	/* DSI_INTL_CTRL */
 	data = MIPI_INP((ctrl->ctrl_base) + 0x0110);
+	data &= DSI_INTR_TOTAL_MASK;
 	data |= DSI_INTR_VIDEO_DONE_MASK;
 
 	MIPI_OUTP((ctrl->ctrl_base) + 0x0110, data);
@@ -1719,6 +1724,7 @@ void mdss_dsi_wait4video_done(struct mdss_dsi_ctrl_pdata *ctrl)
 			msecs_to_jiffies(VSYNC_PERIOD * 4));
 
 	data = MIPI_INP((ctrl->ctrl_base) + 0x0110);
+	data &= DSI_INTR_TOTAL_MASK;
 	data &= ~DSI_INTR_VIDEO_DONE_MASK;
 	MIPI_OUTP((ctrl->ctrl_base) + 0x0110, data);
 }