From 0b92e2f40378d4426145467301f9a249bba5907d Mon Sep 17 00:00:00 2001 From: Philipp Zabel Date: Fri, 21 Jun 2013 10:57:19 +0200 Subject: [PATCH] staging: drm/imx: ipu-dmfc: fix bandwidth allocation The IPU can request up to four pixels per access, which gives four times the bandwidth compared to what the driver currently assumes. After correcting this, we have to increase safety margins for bandwidth requirement calculations. Signed-off-by: Philipp Zabel Acked-by: Sascha Hauer Signed-off-by: Greg Kroah-Hartman --- drivers/staging/imx-drm/ipu-v3/ipu-dmfc.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/drivers/staging/imx-drm/ipu-v3/ipu-dmfc.c b/drivers/staging/imx-drm/ipu-v3/ipu-dmfc.c index 91821bc30f41..1dc9817034b8 100644 --- a/drivers/staging/imx-drm/ipu-v3/ipu-dmfc.c +++ b/drivers/staging/imx-drm/ipu-v3/ipu-dmfc.c @@ -292,7 +292,7 @@ int ipu_dmfc_alloc_bandwidth(struct dmfc_channel *dmfc, { struct ipu_dmfc_priv *priv = dmfc->priv; int slots = dmfc_bandwidth_to_slots(priv, bandwidth_pixel_per_second); - int segment = 0, ret = 0; + int segment = -1, ret = 0; dev_dbg(priv->dev, "dmfc: trying to allocate %ldMpixel/s for IPU channel %d\n", bandwidth_pixel_per_second / 1000000, @@ -307,7 +307,17 @@ int ipu_dmfc_alloc_bandwidth(struct dmfc_channel *dmfc, goto out; } - segment = dmfc_find_slots(priv, slots); + /* Always allocate at least 128*4 bytes (2 slots) */ + if (slots < 2) + slots = 2; + + /* For the MEM_BG channel, first try to allocate twice the slots */ + if (dmfc->data->ipu_channel == IPUV3_CHANNEL_MEM_BG_SYNC) + segment = dmfc_find_slots(priv, slots * 2); + if (segment >= 0) + slots *= 2; + else + segment = dmfc_find_slots(priv, slots); if (segment < 0) { ret = -EBUSY; goto out; @@ -391,7 +401,7 @@ int ipu_dmfc_init(struct ipu_soc *ipu, struct device *dev, unsigned long base, * We have a total bandwidth of clkrate * 4pixel divided * into 8 slots. */ - priv->bandwidth_per_slot = clk_get_rate(ipu_clk) / 8; + priv->bandwidth_per_slot = clk_get_rate(ipu_clk) * 4 / 8; dev_dbg(dev, "dmfc: 8 slots with %ldMpixel/s bandwidth each\n", priv->bandwidth_per_slot / 1000000);