Hi Stan,
On Tue, 2015-02-24 at 15:00 +0200, Stanimir Varbanov wrote:
>
<snip>
> #define SPI_MAX_RATE 50000000
> @@ -143,6 +147,11 @@ struct spi_qup {
> int tx_bytes;
> int rx_bytes;
> int qup_v1;
> +
> + int dma_available;
This is more like 'use dma for this transfer", right?
> + struct dma_slave_configrx_conf;
> + struct dma_slave_configtx_conf;
> + atomic_t dma_outstanding;
Do we really need this one. See below.
> };
>
<snip>
> +
> +static int spi_qup_prep_sg(struct spi_master *master, struct spi_transfer *xfer,
> + enum dma_transfer_direction dir)
> +{
> + struct spi_qup *qup = spi_master_get_devdata(master);
> + unsigned long flags = DMA_PREP_INTERRUPT | DMA_PREP_FENCE;
> + struct dma_async_tx_descriptor *desc;
> + struct scatterlist *sgl;
> + dma_cookie_t cookie;
> + unsigned int nents;
> + struct dma_chan *chan;
> + int ret;
> +
> + if (dir == DMA_MEM_TO_DEV) {
> + chan = master->dma_tx;
> + nents = xfer->tx_sg.nents;
> + sgl = xfer->tx_sg.sgl;
> + } else {
> + chan = master->dma_rx;
> + nents = xfer->rx_sg.nents;
> + sgl = xfer->rx_sg.sgl;
> + }
> +
> + desc = dmaengine_prep_slave_sg(chan, sgl, nents, dir, flags);
> + if (!desc)
> + return -EINVAL;
> +
> + desc->callback = spi_qup_dma_done;
> + desc->callback_param = qup;
What if we attach callback only on RX descriptor and use
dmaengine_tx_status() for TX channel in wait for completion?
> +
> + cookie = dmaengine_submit(desc);
> + ret = dma_submit_error(cookie);
> + if (ret)
> + return ret;
> +
> + atomic_inc(&qup->dma_outstanding);
> +
> + return 0;
> +}
> +
> +static int spi_qup_do_dma(struct spi_master *master, struct spi_transfer *xfer)
> +{
> + struct spi_qup *qup = spi_master_get_devdata(master);
> + int ret;
> +
> + atomic_set(&qup->dma_outstanding, 0);
> +
> + reinit_completion(&qup->done);
Redundant, already done in transfer_one().
> +
> + if (xfer->rx_buf) {
Always true.
> + ret = spi_qup_prep_sg(master, xfer, DMA_DEV_TO_MEM);
> + if (ret)
> + return ret;
> +
> + dma_async_issue_pending(master->dma_rx);
> + }
> +
> + if (xfer->tx_buf) {
Same.
>
+ ret = spi_qup_prep_sg(master, xfer, DMA_MEM_TO_DEV);
> + if (ret)
> + goto err_rx;
> +
> + dma_async_issue_pending(master->dma_tx);
> + }
> +
> + ret = spi_qup_set_state(qup, QUP_STATE_RUN);
> + if (ret) {
> + dev_warn(qup->dev, "cannot set RUN state\n");
> + goto err_tx;
> + }
> +
> + if (!wait_for_completion_timeout(&qup->done, msecs_to_jiffies(1000))) {
transfer_one() calculates timeout dynamically based on transfer length.
Transition in state RUN and wait for completion are already coded in transfer_one().
With little rearrangement they could be removed from here.
> + ret = -ETIMEDOUT;
> + goto err_tx;
> + }
> +
> + return 0;
> +
> +err_tx:
> + if (xfer->tx_buf)
Always true.
> + dmaengine_terminate_all(master->dma_tx);
> +err_rx:
> + if (xfer->rx_buf)
>
Same.
> + dmaengine_terminate_all(master->dma_rx);
> +
> + return ret;
> +}
I don't see reason for this function, based on comments so far :-).
<snip>
>
> @@ -621,10 +881,16 @@ static int spi_qup_probe(struct platform_device *pdev)
> writel_relaxed(0, base + SPI_CONFIG);
> writel_relaxed(SPI_IO_C_NO_TRI_STATE, base + SPI_IO_CONTROL);
>
> + ret = spi_qup_init_dma(master, res->start);
> + if (ret == -EPROBE_DEFER)
> + goto error;
Better move resource allocation before touching hardware.
Otherwise is looking good and I know that is working :-)
Regards,
Ivan
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