media: aspeed: Fix dram hang at res-change

Dram hang could happen in the steps below:
1. start capture/compression
2. out-of-lock watchdog raise irq because of res-change.
3. aspeed_video_irq_res_change do clk-off

At step3, capture/compression could be not accomplished yet. If clk-off
in the middle of video operation, dram controller could hang at ast2500.

Use reset rather than clk-off/on to avoid this problem.

Signed-off-by: Jammy Huang <jammy_huang@aspeedtech.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>

diff --git a/drivers/media/platform/aspeed/aspeed-video.c b/drivers/media/platform/aspeed/aspeed-video.c
index b83e43245277b4730603280e4f00b2b75b25f06b..41cb96f6011021ddd66b2ef322072faca46d0ce0 100644 (file)
--- a/drivers/media/platform/aspeed/aspeed-video.c
+++ b/drivers/media/platform/aspeed/aspeed-video.c
@@ -26,6 +26,7 @@
 #include <linux/workqueue.h>
 #include <linux/debugfs.h>
 #include <linux/ktime.h>
+#include <linux/reset.h>
 #include <linux/regmap.h>
 #include <linux/mfd/syscon.h>
 #include <media/v4l2-ctrls.h>
@@ -310,6 +311,7 @@ struct aspeed_video {
        void __iomem *base;
        struct clk *eclk;
        struct clk *vclk;
+       struct reset_control *reset;
 
        struct device *dev;
        struct v4l2_ctrl_handler ctrl_handler;
@@ -720,6 +722,13 @@ static void aspeed_video_on(struct aspeed_video *video)
        set_bit(VIDEO_CLOCKS_ON, &video->flags);
 }
 
+static void aspeed_video_reset(struct aspeed_video *v)
+{
+       reset_control_assert(v->reset);
+       usleep_range(100, 150);
+       reset_control_deassert(v->reset);
+}
+
 static void aspeed_video_bufs_done(struct aspeed_video *video,
                                   enum vb2_buffer_state state)
 {
@@ -742,7 +751,9 @@ static void aspeed_video_irq_res_change(struct aspeed_video *video, ulong delay)
 
        video->v4l2_input_status = V4L2_IN_ST_NO_SIGNAL;
 
-       aspeed_video_off(video);
+       aspeed_video_write(video, VE_INTERRUPT_CTRL, 0);
+       aspeed_video_write(video, VE_INTERRUPT_STATUS, 0xffffffff);
+       aspeed_video_reset(video);
        aspeed_video_bufs_done(video, VB2_BUF_STATE_ERROR);
 
        schedule_delayed_work(&video->res_work, delay);
@@ -1984,8 +1995,7 @@ static void aspeed_video_stop_streaming(struct vb2_queue *q)
                 * Need to force stop any DMA and try and get HW into a good
                 * state for future calls to start streaming again.
                 */
-               aspeed_video_off(video);
-               aspeed_video_on(video);
+               aspeed_video_reset(video);
 
                aspeed_video_init_regs(video);
 
@@ -2230,6 +2240,12 @@ static int aspeed_video_init(struct aspeed_video *video)
        }
        dev_info(video->dev, "irq %d\n", irq);
 
+       video->reset = devm_reset_control_get(dev, NULL);
+       if (IS_ERR(video->reset)) {
+               dev_err(dev, "Unable to get reset\n");
+               return PTR_ERR(video->reset);
+       }
+
        video->eclk = devm_clk_get(dev, "eclk");
        if (IS_ERR(video->eclk)) {
                dev_err(dev, "Unable to get ECLK\n");