[PATCH] mmc: mmci: Use dma_request_chan() instead dma_request_slave_channel()

From: Peter Ujfalusi
Date: Tue Dec 17 2019 - 06:27:30 EST


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@xxxxxx>
---
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

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