ARM: 7713/1: mmc: mmci: Allow MMCI to request channels with information acquired from DT

Currently, if DMA information isn't passed from platform data, then DMA
will not be used. This patch allows DMA information obtained though Device
Tree to be used as well.

Cc: Chris Ball <cjb@laptop.org>
Cc: linux-mmc@vger.kernel.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

drivers/mmc/host/mmci.c

@@ -310,10 +310,8 @@ static void mmci_dma_setup(struct mmci_host *host)
 	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");
-		return;
-	}
+	host->dma_rx_channel = dma_request_slave_channel(mmc_dev(host->mmc), "rx");
+	host->dma_tx_channel = dma_request_slave_channel(mmc_dev(host->mmc), "tx");
 
 	/* initialize pre request cookie */
 	host->next_data.cookie = 1;
@@ -322,30 +320,33 @@ static void mmci_dma_setup(struct mmci_host *host)
 	dma_cap_zero(mask);
 	dma_cap_set(DMA_SLAVE, mask);
 
-	/*
-	 * If only an RX channel is specified, the driver will
-	 * 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,
+	if (plat && plat->dma_filter) {
+		if (!host->dma_rx_channel && plat->dma_rx_param) {
+			host->dma_rx_channel = dma_request_channel(mask,
 							   plat->dma_filter,
 							   plat->dma_rx_param);
-		/* E.g if no DMA hardware is present */
-		if (!host->dma_rx_channel)
-			dev_err(mmc_dev(host->mmc), "no RX DMA channel\n");
-	}
+			/* 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,
+		if (!host->dma_tx_channel && plat->dma_tx_param) {
+			host->dma_tx_channel = dma_request_channel(mask,
 							   plat->dma_filter,
 							   plat->dma_tx_param);
-		if (!host->dma_tx_channel)
-			dev_warn(mmc_dev(host->mmc), "no TX DMA channel\n");
-	} else {
-		host->dma_tx_channel = host->dma_rx_channel;
+			if (!host->dma_tx_channel)
+				dev_warn(mmc_dev(host->mmc), "no TX DMA channel\n");
+		}
 	}
 
+	/*
+	 * If only an RX channel is specified, the driver will
+	 * attempt to use it bidirectionally, however if it is
+	 * is specified but cannot be located, DMA will be disabled.
+	 */
+	if (host->dma_rx_channel && !host->dma_tx_channel)
+		host->dma_tx_channel = host->dma_rx_channel;
+
 	if (host->dma_rx_channel)
 		rxname = dma_chan_name(host->dma_rx_channel);
 	else