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authorLucas Stach <l.stach@pengutronix.de>2017-03-24 18:01:53 +0100
committerPhilipp Zabel <p.zabel@pengutronix.de>2017-10-11 12:04:23 +0200
commit263c3b8044f9c9356a34fdb2640b52d27e378f9c (patch)
treea42fcead7aad413e5b24dee7c1f34beabf8ad792 /drivers/gpu
parentcda77556447c782b3c9c068f81ef58136cb487c3 (diff)
gpu: ipu-v3: prg: wait for double buffers to be filled on channel startup
Wait for both double buffer to be filled when first starting a channel. This makes channel startup a lot more reliable, probably because it allows the internal state machine to settle before the requests from the IPU are coming in. Signed-off-by: Lucas Stach <l.stach@pengutronix.de> [p.zabel@pengutronix.de: rebased before switch to runtime PM] Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Diffstat (limited to 'drivers/gpu')
-rw-r--r--drivers/gpu/ipu-v3/ipu-prg.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/drivers/gpu/ipu-v3/ipu-prg.c b/drivers/gpu/ipu-v3/ipu-prg.c
index ecc9ea44dc50..0013ca9f72c8 100644
--- a/drivers/gpu/ipu-v3/ipu-prg.c
+++ b/drivers/gpu/ipu-v3/ipu-prg.c
@@ -14,6 +14,7 @@
#include <drm/drm_fourcc.h>
#include <linux/clk.h>
#include <linux/err.h>
+#include <linux/iopoll.h>
#include <linux/mfd/syscon.h>
#include <linux/mfd/syscon/imx6q-iomuxc-gpr.h>
#include <linux/module.h>
@@ -329,6 +330,12 @@ int ipu_prg_channel_configure(struct ipuv3_channel *ipu_chan,
val = IPU_PRG_REG_UPDATE_REG_UPDATE;
writel(val, prg->regs + IPU_PRG_REG_UPDATE);
+ /* wait for both double buffers to be filled */
+ readl_poll_timeout(prg->regs + IPU_PRG_STATUS, val,
+ (val & IPU_PRG_STATUS_BUFFER0_READY(prg_chan)) &&
+ (val & IPU_PRG_STATUS_BUFFER1_READY(prg_chan)),
+ 5, 1000);
+
clk_disable_unprepare(prg->clk_ipg);
chan->enabled = true;