On Wednesday 17 April 2013, Lee Jones wrote:
> #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;
> + const char *chan_name;
> + int count, i;
> + bool do_tx = false, do_rx = false;
>
> if (!plat || !plat->dma_filter) {
> - dev_info(mmc_dev(host->mmc), "no DMA platform data\n");
> - return;
> + if (np) {
> + count = of_property_count_strings(np, "dma-names");
> + for (i = 0; i < count; i++) {
> + of_property_read_string_index(np, "dma-names",
> + i, &chan_name);
> + if (strcmp(chan_name, "tx"))
> + do_tx = true;
> + else if (strcmp(chan_name, "rx"))
> + do_rx = true;
> + }
> + } else {
> + dev_info(mmc_dev(host->mmc), "no DMA platform data\n");
> + return;
> + }
> }
This looks unnecessarily complex.
> /* initialize pre request cookie */
> @@ -321,19 +338,21 @@ 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->dma_rx_param || do_rx) {
> + 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");
> }
Why not just do dma_request_slave_channel_compat() unconditionally here?
It's not an error for MMCI if that fails. If you want to keep the warning
in the case dma_rx_channel is provided by not working, you can do it like
host->dma_rx_channel = dma_request_slave_channel(dev, "rx");
if (!host->dma_rx_channel && plat->dma_rx_param) {
host->dma_rx_channel = dma_request_channel(mask,
plat->dma_filter,
plat->dma_rx_param);
...
}
Arnd
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