mmc: atmel-mci: use probe deferring if dma controller is not ready yet

Return probe defer if requesting a dma channel without a dma controller
probed.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c
index 00f60886c1e5962a1add6cb229a5d8f66e88a30a..62aba9af19f49b19a1bd212bd054f2caff60b71d 100644 (file)
--- a/drivers/mmc/host/atmel-mci.c
+++ b/drivers/mmc/host/atmel-mci.c
@@ -2272,29 +2272,25 @@ static void atmci_cleanup_slot(struct atmel_mci_slot *slot,
        mmc_free_host(slot->mmc);
 }
 
-static bool atmci_configure_dma(struct atmel_mci *host)
+static int atmci_configure_dma(struct atmel_mci *host)
 {
-       if (host == NULL)
-               return false;
+       host->dma.chan = dma_request_slave_channel_reason(&host->pdev->dev,
+                                                       "rxtx");
+       if (IS_ERR(host->dma.chan))
+               return PTR_ERR(host->dma.chan);
+
+       dev_info(&host->pdev->dev, "using %s for DMA transfers\n",
+                dma_chan_name(host->dma.chan));
+
+       host->dma_conf.src_addr = host->mapbase + ATMCI_RDR;
+       host->dma_conf.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+       host->dma_conf.src_maxburst = 1;
+       host->dma_conf.dst_addr = host->mapbase + ATMCI_TDR;
+       host->dma_conf.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+       host->dma_conf.dst_maxburst = 1;
+       host->dma_conf.device_fc = false;
 
-       host->dma.chan = dma_request_slave_channel(&host->pdev->dev, "rxtx");
-       if (!host->dma.chan) {
-               dev_warn(&host->pdev->dev, "no DMA channel available\n");
-               return false;
-       } else {
-               dev_info(&host->pdev->dev,
-                                       "using %s for DMA transfers\n",
-                                       dma_chan_name(host->dma.chan));
-
-               host->dma_conf.src_addr = host->mapbase + ATMCI_RDR;
-               host->dma_conf.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
-               host->dma_conf.src_maxburst = 1;
-               host->dma_conf.dst_addr = host->mapbase + ATMCI_TDR;
-               host->dma_conf.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
-               host->dma_conf.dst_maxburst = 1;
-               host->dma_conf.device_fc = false;
-               return true;
-       }
+       return 0;
 }
 
 /*
@@ -2411,7 +2407,10 @@ static int atmci_probe(struct platform_device *pdev)
 
        /* Get MCI capabilities and set operations according to it */
        atmci_get_cap(host);
-       if (atmci_configure_dma(host)) {
+       ret = atmci_configure_dma(host);
+       if (ret == -EPROBE_DEFER)
+               goto err_dma_probe_defer;
+       if (ret == 0) {
                host->prepare_data = &atmci_prepare_data_dma;
                host->submit_data = &atmci_submit_data_dma;
                host->stop_transfer = &atmci_stop_transfer_dma;
@@ -2496,8 +2495,9 @@ err_init_slot:
        pm_runtime_put_noidle(&pdev->dev);
 
        del_timer_sync(&host->timer);
-       if (host->dma.chan)
+       if (!IS_ERR(host->dma.chan))
                dma_release_channel(host->dma.chan);
+err_dma_probe_defer:
        free_irq(irq, host);
        return ret;
 }
@@ -2523,7 +2523,7 @@ static int atmci_remove(struct platform_device *pdev)
        atmci_readl(host, ATMCI_SR);
 
        del_timer_sync(&host->timer);
-       if (host->dma.chan)
+       if (!IS_ERR(host->dma.chan))
                dma_release_channel(host->dma.chan);
 
        free_irq(platform_get_irq(pdev, 0), host);