[PATCH v2 4/4] mmc: atmel-mci: use probe deferring if dma controller is not ready yet
From: Ulf Hansson <hidden>
Date: 2014-11-25 12:37:20
Also in:
linux-mmc
On 21 November 2014 at 16:33, Ludovic Desroches [off-list ref] wrote:
quoted hunk ↗ jump to hunk
Return probe defer if requesting a dma channel without a dma controller probed. Signed-off-by: Ludovic Desroches <redacted> --- drivers/mmc/host/atmel-mci.c | 46 ++++++++++++++++++++++++-------------------- 1 file changed, 25 insertions(+), 21 deletions(-)diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c index 28546c3..d3c269e 100644 --- a/drivers/mmc/host/atmel-mci.c +++ b/drivers/mmc/host/atmel-mci.c@@ -2265,29 +2265,29 @@ 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; + int ret = 0; - 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; + host->dma.chan = dma_request_slave_channel_reason(&host->pdev->dev, "rxtx"); + if (IS_ERR(host->dma.chan)) { + ret = PTR_ERR(host->dma.chan); + host->dma.chan = NULL; + return ret;
As minor improvement you could just do "return PTR_ERR(host->dma.chan);" Then add a check for "IS_ERR(host->dma.chan)" at those other places that needs it.
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} + + 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 ret; } /*@@ -2403,7 +2403,10 @@ 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;@@ -2476,6 +2479,7 @@ err_init_slot: del_timer_sync(&host->timer); if (host->dma.chan) dma_release_channel(host->dma.chan); +err_dma_probe_defer: free_irq(irq, host); return ret; } --2.0.3
Kind regards Uffe