On 21 November 2014 at 16:33, Ludovic Desroches
<ludovic.desroches@xxxxxxxxx> wrote:
> Return probe defer if requesting a dma channel without a dma controller
> probed.
>
> Signed-off-by: Ludovic Desroches <ludovic.desroches@xxxxxxxxx>
> ---
> drivers/mmc/host/atmel-mci.c | 46 ++++++++++++++++++++++++--------------------
> 1 file changed, 25 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c
> index 28546c3..d3c269e 100644
> --- a/drivers/mmc/host/atmel-mci.c
> +++ b/drivers/mmc/host/atmel-mci.c
> @@ -2265,29 +2265,29 @@ static void atmci_cleanup_slot(struct atmel_mci_slot *slot,
> mmc_free_host(slot->mmc);
> }
>
> -static bool atmci_configure_dma(struct atmel_mci *host)
> +static int atmci_configure_dma(struct atmel_mci *host)
> {
> - if (host == NULL)
> - return false;
> + int ret = 0;
>
> - host->dma.chan = dma_request_slave_channel(&host->pdev->dev, "rxtx");
> - if (!host->dma.chan) {
> - dev_warn(&host->pdev->dev, "no DMA channel available\n");
> - return false;
> - } else {
> - dev_info(&host->pdev->dev,
> - "using %s for DMA transfers\n",
> - dma_chan_name(host->dma.chan));
> -
> - host->dma_conf.src_addr = host->mapbase + ATMCI_RDR;
> - host->dma_conf.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
> - host->dma_conf.src_maxburst = 1;
> - host->dma_conf.dst_addr = host->mapbase + ATMCI_TDR;
> - host->dma_conf.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
> - host->dma_conf.dst_maxburst = 1;
> - host->dma_conf.device_fc = false;
> - return true;
> + host->dma.chan = dma_request_slave_channel_reason(&host->pdev->dev, "rxtx");
> + if (IS_ERR(host->dma.chan)) {
> + ret = PTR_ERR(host->dma.chan);
> + host->dma.chan = NULL;
> + return ret;
As minor improvement you could just do "return PTR_ERR(host->dma.chan);"
Then add a check for "IS_ERR(host->dma.chan)" at those other places
that needs it.
> }
> +
> + dev_info(&host->pdev->dev, "using %s for DMA transfers\n",
> + dma_chan_name(host->dma.chan));
> +
> + host->dma_conf.src_addr = host->mapbase + ATMCI_RDR;
> + host->dma_conf.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
> + host->dma_conf.src_maxburst = 1;
> + host->dma_conf.dst_addr = host->mapbase + ATMCI_TDR;
> + host->dma_conf.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
> + host->dma_conf.dst_maxburst = 1;
> + host->dma_conf.device_fc = false;
> +
> + return ret;
> }
>
> /*
> @@ -2403,7 +2403,10 @@ static int atmci_probe(struct platform_device *pdev)
>
> /* Get MCI capabilities and set operations according to it */
> atmci_get_cap(host);
> - if (atmci_configure_dma(host)) {
> + ret = atmci_configure_dma(host);
> + if (ret == -EPROBE_DEFER)
> + goto err_dma_probe_defer;
> + if (ret == 0) {
> host->prepare_data = &atmci_prepare_data_dma;
> host->submit_data = &atmci_submit_data_dma;
> host->stop_transfer = &atmci_stop_transfer_dma;
> @@ -2476,6 +2479,7 @@ err_init_slot:
> del_timer_sync(&host->timer);
> if (host->dma.chan)
> dma_release_channel(host->dma.chan);
> +err_dma_probe_defer:
> free_irq(irq, host);
> return ret;
> }
> --
> 2.0.3
>
Kind regards
Uffe
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