From 935da5e5100f57d843cac4781b21f1c235059aa0 Mon Sep 17 00:00:00 2001 From: Vignesh Raghavendra Date: Mon, 1 Jun 2020 12:34:41 +0530 Subject: [PATCH] mtd: spi-nor: cadence-quadspi: Handle probe deferral while requesting DMA channel dma_request_chan_by_mask() can throw EPROBE_DEFER if DMA provider is not yet probed. Currently driver just falls back to using PIO mode (which is less efficient) in this case. Instead return probe deferral error as is so that driver will be re probed once DMA provider is available. Signed-off-by: Vignesh Raghavendra Reviewed-by: Tudor Ambarus Acked-by: Tudor Ambarus Link: https://lore.kernel.org/r/20200601070444.16923-6-vigneshr@ti.com Signed-off-by: Mark Brown --- .../mtd/spi-nor/controllers/cadence-quadspi.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) diff --git a/drivers/mtd/spi-nor/controllers/cadence-quadspi.c b/drivers/mtd/spi-nor/controllers/cadence-quadspi.c index 608ca657ff7f..0570ebca135a 100644 --- a/drivers/mtd/spi-nor/controllers/cadence-quadspi.c +++ b/drivers/mtd/spi-nor/controllers/cadence-quadspi.c @@ -1169,7 +1169,7 @@ static void cqspi_controller_init(struct cqspi_st *cqspi) cqspi_controller_enable(cqspi, 1); } -static void cqspi_request_mmap_dma(struct cqspi_st *cqspi) +static int cqspi_request_mmap_dma(struct cqspi_st *cqspi) { dma_cap_mask_t mask; @@ -1178,11 +1178,16 @@ static void cqspi_request_mmap_dma(struct cqspi_st *cqspi) cqspi->rx_chan = dma_request_chan_by_mask(&mask); if (IS_ERR(cqspi->rx_chan)) { - dev_err(&cqspi->pdev->dev, "No Rx DMA available\n"); + int ret = PTR_ERR(cqspi->rx_chan); + + if (ret != -EPROBE_DEFER) + dev_err(&cqspi->pdev->dev, "No Rx DMA available\n"); cqspi->rx_chan = NULL; - return; + return ret; } init_completion(&cqspi->rx_dma_complete); + + return 0; } static const struct spi_nor_controller_ops cqspi_controller_ops = { @@ -1269,8 +1274,11 @@ static int cqspi_setup_flash(struct cqspi_st *cqspi, struct device_node *np) dev_dbg(nor->dev, "using direct mode for %s\n", mtd->name); - if (!cqspi->rx_chan) - cqspi_request_mmap_dma(cqspi); + if (!cqspi->rx_chan) { + ret = cqspi_request_mmap_dma(cqspi); + if (ret == -EPROBE_DEFER) + goto err; + } } }