Patchwork mmc: mmci: Allow MMCI to request channels with information acquired from DT

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Submitter Lee Jones
Date April 17, 2013, 3:04 p.m.
Message ID <20130417150437.GA3137@gmail.com>
Download mbox | patch
Permalink /patch/237266/
State New
Headers show

Comments

Lee Jones - April 17, 2013, 3:04 p.m.
> 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.
Arnd Bergmann - April 17, 2013, 3:31 p.m.
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

Patch

diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
index 372e921..1fd212a 100644
--- a/drivers/mmc/host/mmci.c
+++ b/drivers/mmc/host/mmci.c
@@ -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;
 	}
 
@@ -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");
 	}
 
-	if (plat->dma_tx_param) {
-		host->dma_tx_channel = dma_request_channel(mask,
-							   plat->dma_filter,
-							   plat->dma_tx_param);
+	if ((plat && plat->dma_tx_param) || np) {
+		host->dma_tx_channel = dma_request_slave_channel_compat(mask,
+					(plat) ? plat->dma_filter : NULL,
+					(plat) ? plat->dma_tx_param : NULL,
+					&dev->dev, "tx");
 		if (!host->dma_tx_channel)
 			dev_warn(mmc_dev(host->mmc), "no TX DMA channel\n");
 	} else {
@@ -1538,7 +1542,7 @@  static int mmci_probe(struct amba_device *dev,
 		 amba_rev(dev), (unsigned long long)dev->res.start,
 		 dev->irq[0], dev->irq[1]);
 
-	mmci_dma_setup(host);
+	mmci_dma_setup(dev, host);
 
 	pm_runtime_set_autosuspend_delay(&dev->dev, 50);
 	pm_runtime_use_autosuspend(&dev->dev);