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[v5,3/8] drm/tilcdc: Write to LCDC_END_OF_INT_IND_REG at the end of IRQ function

Message ID 992aae88f85d588cec5d6f221cd68afb166d5f6d.1466155291.git.jsarha@ti.com (mailing list archive)
State New, archived
Headers show

Commit Message

Jyri Sarha June 17, 2016, 9:22 a.m. UTC 
Reorder the IRQ function so that the write to LCDC_END_OF_INT_IND_REG
is done last. The write to LCDC_END_OF_INT_IND_REG indicates to LCDC
that the interrupt service routine has completed (see section
13.3.6.1.6 in AM335x TRM). This is needed if LCDC's ipgvmodirq module
is configured for pulse interrupts.

Signed-off-by: Jyri Sarha <jsarha@ti.com>
---
 drivers/gpu/drm/tilcdc/tilcdc_crtc.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)
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Patch

diff --git a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
index 6309d3c..65284e9 100644
--- a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
+++ b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
@@ -725,12 +725,16 @@  irqreturn_t tilcdc_crtc_irq(struct drm_crtc *crtc)
 			tilcdc_crtc->frame_intact = true;
 	}
 
+	if (stat & LCDC_FIFO_UNDERFLOW)
+		dev_err_ratelimited(dev->dev, "%s(0x%08x): FIFO underfow",
+				    __func__, stat);
+
+	/* For revision 2 only */
 	if (priv->rev == 2) {
 		if (stat & LCDC_FRAME_DONE) {
 			tilcdc_crtc->frame_done = true;
 			wake_up(&tilcdc_crtc->frame_done_wq);
 		}
-		tilcdc_write(dev, LCDC_END_OF_INT_IND_REG, 0);
 
 		if (stat & LCDC_SYNC_LOST) {
 			dev_err_ratelimited(dev->dev, "%s(0x%08x): Sync lost",
@@ -743,11 +747,12 @@  irqreturn_t tilcdc_crtc_irq(struct drm_crtc *crtc)
 					     LCDC_SYNC_LOST);
 			}
 		}
-	}
 
-	if (stat & LCDC_FIFO_UNDERFLOW)
-		dev_err_ratelimited(dev->dev, "%s(0x%08x): FIFO underfow",
-				    __func__, stat);
+		/* Indicate to LCDC that the interrupt service routine has
+		 * completed, see 13.3.6.1.6 in AM335x TRM.
+		 */
+		tilcdc_write(dev, LCDC_END_OF_INT_IND_REG, 0);
+	}
 
 	return IRQ_HANDLED;
 }