drm/lima: handle shared irq case for lima_pp_bcast_irq_handler

On Hikey board all lima ip blocks are shared with one irq.
This patch avoids a NULL ptr deref crash on this platform
on startup. Tested with Weston and kmscube.

Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Qiang Yu <yuq825@gmail.com>
Signed-off-by: Qiang Yu <yuq825@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1555662781-22570-7-git-send-email-peter.griffin@linaro.org

diff --git a/drivers/gpu/drm/lima/lima_pp.c b/drivers/gpu/drm/lima/lima_pp.c
index d29721e177bf97f7595cb6605c6d6c79795e5a4e..8fef224b93c8568fc70bd483739a7cd84d5e49e6 100644 (file)
--- a/drivers/gpu/drm/lima/lima_pp.c
+++ b/drivers/gpu/drm/lima/lima_pp.c
@@ -64,7 +64,13 @@ static irqreturn_t lima_pp_bcast_irq_handler(int irq, void *data)
        struct lima_ip *pp_bcast = data;
        struct lima_device *dev = pp_bcast->dev;
        struct lima_sched_pipe *pipe = dev->pipe + lima_pipe_pp;
-       struct drm_lima_m450_pp_frame *frame = pipe->current_task->frame;
+       struct drm_lima_m450_pp_frame *frame;
+
+       /* for shared irq case */
+       if (!pipe->current_task)
+               return IRQ_NONE;
+
+       frame = pipe->current_task->frame;
 
        for (i = 0; i < frame->num_pp; i++) {
                struct lima_ip *ip = pipe->processor[i];