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
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