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imx-drm: ipu-dmfc: wait for FIFOs to run empty before disabling

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Disabling the DMFC module while there is still data in the FIFOs could
cause the "new frame before end of frame" error state when the DMFC is
enabled again.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Philipp Zabel 2014-04-14 23:53:18 +02:00 committed by Russell King
parent 1707550468
commit 47348661c4
1 changed files with 23 additions and 2 deletions
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25
drivers/staging/imx-drm/ipu-v3/ipu-dmfc.c
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@ -28,7 +28,12 @@
#define DMFC_GENERAL1 0x0014
#define DMFC_GENERAL2 0x0018
#define DMFC_IC_CTRL 0x001c
#define DMFC_STAT 0x0020
#define DMFC_WR_CHAN_ALT 0x0020
#define DMFC_WR_CHAN_DEF_ALT 0x0024
#define DMFC_DP_CHAN_ALT 0x0028
#define DMFC_DP_CHAN_DEF_ALT 0x002c
#define DMFC_GENERAL1_ALT 0x0030
#define DMFC_STAT 0x0034
#define DMFC_WR_CHAN_1_28 0
#define DMFC_WR_CHAN_2_41 8
@ -133,6 +138,20 @@ int ipu_dmfc_enable_channel(struct dmfc_channel *dmfc)
}
EXPORT_SYMBOL_GPL(ipu_dmfc_enable_channel);
static void ipu_dmfc_wait_fifos(struct ipu_dmfc_priv *priv)
{
unsigned long timeout = jiffies + msecs_to_jiffies(1000);
while ((readl(priv->base + DMFC_STAT) & 0x02fff000) != 0x02fff000) {
if (time_after(jiffies, timeout)) {
dev_warn(priv->dev,
"Timeout waiting for DMFC FIFOs to clear\n");
break;
}
cpu_relax();
}
}
void ipu_dmfc_disable_channel(struct dmfc_channel *dmfc)
{
struct ipu_dmfc_priv *priv = dmfc->priv;
@ -141,8 +160,10 @@ void ipu_dmfc_disable_channel(struct dmfc_channel *dmfc)
priv->use_count--;
if (!priv->use_count)
if (!priv->use_count) {
ipu_dmfc_wait_fifos(priv);
ipu_module_disable(priv->ipu, IPU_CONF_DMFC_EN);
}
if (priv->use_count < 0)
priv->use_count = 0;