On Wednesday 17 April 2013, Lee Jones wrote:
> > This looks unnecessarily complex.
>
> That thought did cross my mind.
>
> > Why not just do dma_request_slave_channel_compat() unconditionally here?
>
> So how about something like this instead, as it keeps the current
> semantics, and only differs in the case of DT.
Yes, looks better.
> @@ -298,14 +298,16 @@ static void mmci_init_sg(struct mmci_host *host, struct
> mmc_data *data)
> * no custom DMA interfaces are supported.
> */
> #ifdef CONFIG_DMA_ENGINE
> -static void mmci_dma_setup(struct mmci_host *host)
> +static void mmci_dma_setup(struct amba_device *dev,
> + struct mmci_host *host)
> {
> + struct device_node *np = dev->dev.of_node;
> struct mmci_platform_data *plat = host->plat;
> const char *rxname, *txname;
> dma_cap_mask_t mask;
>
> - if (!plat || !plat->dma_filter) {
> - dev_info(mmc_dev(host->mmc), "no DMA platform data\n");
> + if (!(plat && plat->dma_filter) && !np) {
> + dev_info(mmc_dev(host->mmc), "no DMA platform data or DT\n");
> return;
> }
I think you can further simplify this, given that in the DT case we always
allocate a zeroed mmci_platform_data for host->plat, so !plat cannot happen
when we get here.
> @@ -321,19 +323,21 @@ static void mmci_dma_setup(struct mmci_host *host)
> * attempt to use it bidirectionally, however if it is
> * is specified but cannot be located, DMA will be disabled.
> */
> - if (plat->dma_rx_param) {
> - host->dma_rx_channel = dma_request_channel(mask,
> - plat->dma_filter,
> - plat->dma_rx_param);
> + if ((plat && plat->dma_rx_param) || np) {
> + host->dma_rx_channel = dma_request_slave_channel_compat(mask,
> + (plat) ? plat->dma_filter : NULL,
> + (plat) ? plat->dma_rx_param : NULL,
> + &dev->dev, "rx");
> /* E.g if no DMA hardware is present */
> if (!host->dma_rx_channel)
> dev_err(mmc_dev(host->mmc), "no RX DMA channel\n");
And based on that, you can unconditionally pass plat->dma_filter and
plat->dma_rx_param here. In case of DT, they will be NULL, and they
will not be used either.
Arnd
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