linux-kernel - [PATCH] mmc: mmci: Use dma_request_chan() instead dma_request_slave

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Date:   Tue, 17 Dec 2019 13:27:37 +0200
From:   Peter Ujfalusi <peter.ujfalusi@...com>
To:     <ulf.hansson@...aro.org>
CC:     <vkoul@...nel.org>, <linux-mmc@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: [PATCH] mmc: mmci: Use dma_request_chan() instead dma_request_slave_channel()

dma_request_slave_channel() is a wrapper on top of dma_request_chan()
eating up the error code.

By using dma_request_chan() directly the driver can support deferred
probing against DMA.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@...com>
---
 drivers/mmc/host/mmci.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
index caaa4687de93..bf9573274481 100644
--- a/drivers/mmc/host/mmci.c
+++ b/drivers/mmc/host/mmci.c
@@ -706,10 +706,20 @@ int mmci_dmae_setup(struct mmci_host *host)
 
 	host->dma_priv = dmae;
 
-	dmae->rx_channel = dma_request_slave_channel(mmc_dev(host->mmc),
-						     "rx");
-	dmae->tx_channel = dma_request_slave_channel(mmc_dev(host->mmc),
-						     "tx");
+	dmae->rx_channel = dma_request_chan(mmc_dev(host->mmc), "rx");
+	if (IS_ERR(dmae->rx_channel)) {
+		int ret = PTR_ERR(dmae->rx_channel);
+		dmae->rx_channel = NULL;
+		return ret;
+	}
+
+	dmae->tx_channel = dma_request_chan(mmc_dev(host->mmc), "tx");
+	if (IS_ERR(dmae->tx_channel)) {
+		if (PTR_ERR(dmae->tx_channel) == -EPROBE_DEFER)
+			dev_warn(mmc_dev(host->mmc),
+				 "Deferred probe for TX channel ignored\n");
+		dmae->tx_channel = NULL;
+	}
 
 	/*
 	 * If only an RX channel is specified, the driver will
-- 
Peter

Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
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