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Commit 37e06a12 authored by Vignesh Raghavendra's avatar Vignesh Raghavendra Committed by Greg Kroah-Hartman
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mtd: spi-nor: cadence-quadspi: Handle probe deferral while requesting DMA channel 



[ Upstream commit 935da5e5100f57d843cac4781b21f1c235059aa0 ]

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: default avatarVignesh Raghavendra <vigneshr@ti.com>
Reviewed-by: default avatarTudor Ambarus <tudor.ambarus@microchip.com>
Acked-by: default avatarTudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20200601070444.16923-6-vigneshr@ti.com


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
Stable-dep-of: 2087e85bb66e ("spi: cadence-quadspi: fix suspend-resume implementations")
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent cf2ed090

drivers/mtd/spi-nor/cadence-quadspi.c

+13 −5
Original line number Diff line number Diff line
@@ -1162,7 +1162,7 @@ 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;
@@ -1171,11 +1171,16 @@ 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)) {

		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 int cqspi_setup_flash(struct cqspi_st *cqspi, struct device_node *np)
@@ -1256,8 +1261,11 @@ 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;

			}

		}

	}