From f16921275cc3c2442d0b95225785a601603b990f Mon Sep 17 00:00:00 2001 From: Robert Jarzmik Date: Tue, 16 Feb 2016 22:54:02 +0100 Subject: [PATCH] dmaengine: pxa_dma: fix cyclic transfers While testing audio with pxa2xx-ac97, underrun were happening while the user application was correctly feeding the music. Debug proved that the cyclic transfer is not cyclic, ie. the last descriptor did not loop on the first. Another issue is that the descriptor length was always set to 8192, because of an trivial operator issue. This was tested on a pxa27x platform. Fixes: a57e16cf0333 ("dmaengine: pxa: add pxa dmaengine driver") Reported-by: Vasily Khoruzhick Tested-by: Vasily Khoruzhick Signed-off-by: Robert Jarzmik Signed-off-by: Vinod Koul --- drivers/dma/pxa_dma.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/dma/pxa_dma.c b/drivers/dma/pxa_dma.c index f2a0310ae771..debca824bed6 100644 --- a/drivers/dma/pxa_dma.c +++ b/drivers/dma/pxa_dma.c @@ -583,6 +583,8 @@ static void set_updater_desc(struct pxad_desc_sw *sw_desc, (PXA_DCMD_LENGTH & sizeof(u32)); if (flags & DMA_PREP_INTERRUPT) updater->dcmd |= PXA_DCMD_ENDIRQEN; + if (sw_desc->cyclic) + sw_desc->hw_desc[sw_desc->nb_desc - 2]->ddadr = sw_desc->first; } static bool is_desc_completed(struct virt_dma_desc *vd) @@ -673,6 +675,10 @@ static irqreturn_t pxad_chan_handler(int irq, void *dev_id) dev_dbg(&chan->vc.chan.dev->device, "%s(): checking txd %p[%x]: completed=%d\n", __func__, vd, vd->tx.cookie, is_desc_completed(vd)); + if (to_pxad_sw_desc(vd)->cyclic) { + vchan_cyclic_callback(vd); + break; + } if (is_desc_completed(vd)) { list_del(&vd->node); vchan_cookie_complete(vd); @@ -1080,7 +1086,7 @@ pxad_prep_dma_cyclic(struct dma_chan *dchan, return NULL; pxad_get_config(chan, dir, &dcmd, &dsadr, &dtadr); - dcmd |= PXA_DCMD_ENDIRQEN | (PXA_DCMD_LENGTH | period_len); + dcmd |= PXA_DCMD_ENDIRQEN | (PXA_DCMD_LENGTH & period_len); dev_dbg(&chan->vc.chan.dev->device, "%s(): buf_addr=0x%lx len=%zu period=%zu dir=%d flags=%lx\n", __func__, (unsigned long)buf_addr, len, period_len, dir, flags); -- 2.20.1