On Mon, Oct 05, 2015 at 01:10:07PM +0100, Jon Hunter wrote: > +static enum dma_status tegra_adma_tx_status(struct dma_chan *dc, > + dma_cookie_t cookie, > + struct dma_tx_state *txstate) > +{ > + struct tegra_adma_chan *tdc = to_tegra_adma_chan(dc); > + struct tegra_adma_desc *desc; > + struct virt_dma_desc *vd; > + enum dma_status ret; > + unsigned long flags; > + unsigned int residual; > + > + spin_lock_irqsave(&tdc->lock, flags); > + > + ret = dma_cookie_status(dc, cookie, txstate); > + if (ret == DMA_COMPLETE) { > + spin_unlock_irqrestore(&tdc->lock, flags); > + return ret; > + } txstate can be NULL, upon which below code doesn't help in getting executed so bailing here or above case is fine > +static struct dma_async_tx_descriptor *tegra_adma_prep_dma_cyclic( > + struct dma_chan *dc, dma_addr_t buf_addr, size_t buf_len, > + size_t period_len, enum dma_transfer_direction direction, > + unsigned long flags) > +{ > + struct tegra_adma_chan *tdc = to_tegra_adma_chan(dc); > + struct tegra_adma_desc *desc = NULL; > + > + if (!tdc->config_valid) { > + dev_err(tdc2dev(tdc), "ADMA slave configuration not set\n"); > + return NULL; > + } > + > + if (!buf_len || !period_len || period_len > ADMA_CH_TC_COUNT_MASK) { > + dev_err(tdc2dev(tdc), "invalid buffer/period len\n"); > + return NULL; > + } > + > + if (buf_len % period_len) { > + dev_err(tdc2dev(tdc), "buf_len not a multiple of period_len\n"); > + return NULL; > + } > + > + if (!IS_ALIGNED(buf_addr, 4)) { > + dev_err(tdc2dev(tdc), "invalid buffer alignment\n"); > + return NULL; > + } > + > + desc = kzalloc(sizeof(*desc), GFP_ATOMIC); we recommend GFP_NOWAIT for the subsystem > +static int tegra_adma_remove(struct platform_device *pdev) > +{ > + struct tegra_adma *tdma = platform_get_drvdata(pdev); > + struct tegra_adma_chan *tdc; > + int i; > + > + dma_async_device_unregister(&tdma->dma_dev); > + > + for (i = 0; i < tdma->nr_channels; ++i) { > + tdc = &tdma->channels[i]; > + tasklet_kill(&tdc->vc.task); > + } this is good, but your irq is still active and can fire and thus trigger more tasklets! -- ~Vinod -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html