From: Andy Shevchenko <[email protected]> Accordingly to the documentation the CH_DRAIN bit enforses single bursts when channel is going to be suspended. This, in case when channel will be resumed, makes data to flow in non-optimal mode until DMA returns to full burst mode. The fix differentiates pause / resume cycle from pause / terminate and sets CH_DRAIN bit accordingly.
Signed-off-by: Andy Shevchenko <[email protected]> Signed-off-by: Vinod Koul <[email protected]> (cherry picked from commit 2e9b55becc905207eb01e24bc282f8062cc497b5) Signed-off-by: Tan Jui Nee <[email protected]> --- drivers/dma/idma64.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/drivers/dma/idma64.c b/drivers/dma/idma64.c index c7da43c..7d56b47 100644 --- a/drivers/dma/idma64.c +++ b/drivers/dma/idma64.c @@ -65,9 +65,6 @@ static void idma64_chan_init(struct idma64 *idma64, struct idma64_chan *idma64c) u32 cfghi = IDMA64C_CFGH_SRC_PER(1) | IDMA64C_CFGH_DST_PER(0); u32 cfglo = 0; - /* Enforce FIFO drain when channel is suspended */ - cfglo |= IDMA64C_CFGL_CH_DRAIN; - /* Set default burst alignment */ cfglo |= IDMA64C_CFGL_DST_BURST_ALIGN | IDMA64C_CFGL_SRC_BURST_ALIGN; @@ -428,12 +425,17 @@ static int idma64_slave_config(struct dma_chan *chan, return 0; } -static void idma64_chan_deactivate(struct idma64_chan *idma64c) +static void idma64_chan_deactivate(struct idma64_chan *idma64c, bool drain) { unsigned short count = 100; u32 cfglo; cfglo = channel_readl(idma64c, CFG_LO); + if (drain) + cfglo |= IDMA64C_CFGL_CH_DRAIN; + else + cfglo &= ~IDMA64C_CFGL_CH_DRAIN; + channel_writel(idma64c, CFG_LO, cfglo | IDMA64C_CFGL_CH_SUSP); do { udelay(1); @@ -456,7 +458,7 @@ static int idma64_pause(struct dma_chan *chan) spin_lock_irqsave(&idma64c->vchan.lock, flags); if (idma64c->desc && idma64c->desc->status == DMA_IN_PROGRESS) { - idma64_chan_deactivate(idma64c); + idma64_chan_deactivate(idma64c, false); idma64c->desc->status = DMA_PAUSED; } spin_unlock_irqrestore(&idma64c->vchan.lock, flags); @@ -486,7 +488,7 @@ static int idma64_terminate_all(struct dma_chan *chan) LIST_HEAD(head); spin_lock_irqsave(&idma64c->vchan.lock, flags); - idma64_chan_deactivate(idma64c); + idma64_chan_deactivate(idma64c, true); idma64_stop_transfer(idma64c); if (idma64c->desc) { idma64_vdesc_free(&idma64c->desc->vdesc); -- 1.9.1 -- _______________________________________________ linux-yocto mailing list [email protected] https://lists.yoctoproject.org/listinfo/linux-yocto
