Unverified Commit 32f2fc5d authored by Vignesh Raghavendra's avatar Vignesh Raghavendra Committed by Mark Brown
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spi: spi-omap2-mcspi: Support probe deferral for DMA channels 



dma_request_channel() can return -EPROBE_DEFER, if DMA driver is not
ready. Currently driver just falls back to PIO mode on probe deferral.
Fix this by requesting all required channels during probe and
propagating EPROBE_DEFER error code.

Signed-off-by: default avatarVignesh Raghavendra <vigneshr@ti.com>
Link: https://lore.kernel.org/r/20200204124816.16735-3-vigneshr@ti.com


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent e4e8276a

drivers/spi/spi-omap2-mcspi.c

+38 −39
Original line number Diff line number Diff line
@@ -975,20 +975,12 @@ static int omap2_mcspi_setup_transfer(struct spi_device *spi, 
 * Note that we currently allow DMA only if we get a channel

 * for both rx and tx. Otherwise we'll do PIO for both rx and tx.

 */

static int omap2_mcspi_request_dma(struct spi_device *spi)

static int omap2_mcspi_request_dma(struct omap2_mcspi *mcspi,

				   struct omap2_mcspi_dma *mcspi_dma)

{

	struct spi_master	*master = spi->master;

	struct omap2_mcspi	*mcspi;

	struct omap2_mcspi_dma	*mcspi_dma;

	int ret = 0;



	mcspi = spi_master_get_devdata(master);

	mcspi_dma = mcspi->dma_channels + spi->chip_select;



	init_completion(&mcspi_dma->dma_rx_completion);

	init_completion(&mcspi_dma->dma_tx_completion);



	mcspi_dma->dma_rx = dma_request_chan(&master->dev,

	mcspi_dma->dma_rx = dma_request_chan(mcspi->dev,

					     mcspi_dma->dma_rx_ch_name);

	if (IS_ERR(mcspi_dma->dma_rx)) {

		ret = PTR_ERR(mcspi_dma->dma_rx);
@@ -996,7 +988,7 @@ static int omap2_mcspi_request_dma(struct spi_device *spi) 
		goto no_dma;

	}



	mcspi_dma->dma_tx = dma_request_chan(&master->dev,

	mcspi_dma->dma_tx = dma_request_chan(mcspi->dev,

					     mcspi_dma->dma_tx_ch_name);

	if (IS_ERR(mcspi_dma->dma_tx)) {

		ret = PTR_ERR(mcspi_dma->dma_tx);
@@ -1005,20 +997,40 @@ static int omap2_mcspi_request_dma(struct spi_device *spi) 
		mcspi_dma->dma_rx = NULL;

	}



	init_completion(&mcspi_dma->dma_rx_completion);

	init_completion(&mcspi_dma->dma_tx_completion);



no_dma:

	return ret;

}



static void omap2_mcspi_release_dma(struct spi_master *master)

{

	struct omap2_mcspi *mcspi = spi_master_get_devdata(master);

	struct omap2_mcspi_dma	*mcspi_dma;

	int i;



	for (i = 0; i < master->num_chipselect; i++) {

		mcspi_dma = &mcspi->dma_channels[i];



		if (mcspi_dma->dma_rx) {

			dma_release_channel(mcspi_dma->dma_rx);

			mcspi_dma->dma_rx = NULL;

		}

		if (mcspi_dma->dma_tx) {

			dma_release_channel(mcspi_dma->dma_tx);

			mcspi_dma->dma_tx = NULL;

		}

	}

}



static int omap2_mcspi_setup(struct spi_device *spi)

{

	int			ret;

	struct omap2_mcspi	*mcspi = spi_master_get_devdata(spi->master);

	struct omap2_mcspi_regs	*ctx = &mcspi->ctx;

	struct omap2_mcspi_dma	*mcspi_dma;

	struct omap2_mcspi_cs	*cs = spi->controller_state;



	mcspi_dma = &mcspi->dma_channels[spi->chip_select];



	if (!cs) {

		cs = kzalloc(sizeof *cs, GFP_KERNEL);

		if (!cs)
@@ -1043,13 +1055,6 @@ static int omap2_mcspi_setup(struct spi_device *spi) 
		}

	}



	if (!mcspi_dma->dma_rx || !mcspi_dma->dma_tx) {

		ret = omap2_mcspi_request_dma(spi);

		if (ret)

			dev_warn(&spi->dev, "not using DMA for McSPI (%d)\n",

				 ret);

	}



	ret = pm_runtime_get_sync(mcspi->dev);

	if (ret < 0) {

		pm_runtime_put_noidle(mcspi->dev);
@@ -1066,12 +1071,8 @@ static int omap2_mcspi_setup(struct spi_device *spi) 


static void omap2_mcspi_cleanup(struct spi_device *spi)

{

	struct omap2_mcspi	*mcspi;

	struct omap2_mcspi_dma	*mcspi_dma;

	struct omap2_mcspi_cs	*cs;



	mcspi = spi_master_get_devdata(spi->master);



	if (spi->controller_state) {

		/* Unlink controller state from context save list */

		cs = spi->controller_state;
@@ -1080,19 +1081,6 @@ static void omap2_mcspi_cleanup(struct spi_device *spi) 
		kfree(cs);

	}



	if (spi->chip_select < spi->master->num_chipselect) {

		mcspi_dma = &mcspi->dma_channels[spi->chip_select];



		if (mcspi_dma->dma_rx) {

			dma_release_channel(mcspi_dma->dma_rx);

			mcspi_dma->dma_rx = NULL;

		}

		if (mcspi_dma->dma_tx) {

			dma_release_channel(mcspi_dma->dma_tx);

			mcspi_dma->dma_tx = NULL;

		}

	}



	if (gpio_is_valid(spi->cs_gpio))

		gpio_free(spi->cs_gpio);

}
@@ -1303,6 +1291,9 @@ static bool omap2_mcspi_can_dma(struct spi_master *master, 
	if (spi_controller_is_slave(master))

		return true;



	master->dma_rx = mcspi_dma->dma_rx;

	master->dma_tx = mcspi_dma->dma_tx;



	return (xfer->len >= DMA_MIN_BYTES);

}
@@ -1490,6 +1481,11 @@ static int omap2_mcspi_probe(struct platform_device *pdev) 
	for (i = 0; i < master->num_chipselect; i++) {

		sprintf(mcspi->dma_channels[i].dma_rx_ch_name, "rx%d", i);

		sprintf(mcspi->dma_channels[i].dma_tx_ch_name, "tx%d", i);



		status = omap2_mcspi_request_dma(mcspi,

						 &mcspi->dma_channels[i]);

		if (status == -EPROBE_DEFER)

			goto free_master;

	}



	status = platform_get_irq(pdev, 0);
@@ -1527,6 +1523,7 @@ disable_pm: 
	pm_runtime_put_sync(&pdev->dev);

	pm_runtime_disable(&pdev->dev);

free_master:

	omap2_mcspi_release_dma(master);

	spi_master_put(master);

	return status;

}
@@ -1536,6 +1533,8 @@ static int omap2_mcspi_remove(struct platform_device *pdev) 
	struct spi_master *master = platform_get_drvdata(pdev);

	struct omap2_mcspi *mcspi = spi_master_get_devdata(master);



	omap2_mcspi_release_dma(master);



	pm_runtime_dont_use_autosuspend(mcspi->dev);

	pm_runtime_put_sync(mcspi->dev);

	pm_runtime_disable(&pdev->dev);

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