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Commit f12ae171 authored by Anton Bondarenko's avatar Anton Bondarenko Committed by Mark Brown
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spi: imx: add support for all SPI word width for DMA 



DMA transfer for SPI was limited to up to 8 bits word size until now.
Sync in SPI burst size and DMA bus width is necessary to correctly
support 16 and 32 BPW.

Signed-off-by: default avatarAnton Bondarenko <anton.bondarenko.sama@gmail.com>
Signed-off-by: default avatarSascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent 882f329f

drivers/spi/spi-imx.c

+91 −27
Original line number Diff line number Diff line
@@ -89,11 +89,15 @@ struct spi_imx_data { 


	struct completion xfer_done;

	void __iomem *base;

	unsigned long base_phys;



	struct clk *clk_per;

	struct clk *clk_ipg;

	unsigned long spi_clk;

	unsigned int spi_bus_clk;



	unsigned int bytes_per_word;



	unsigned int count;

	void (*tx)(struct spi_imx_data *);

	void (*rx)(struct spi_imx_data *);
@@ -199,15 +203,35 @@ static unsigned int spi_imx_clkdiv_2(unsigned int fin, 
	return 7;

}



static int spi_imx_bytes_per_word(const int bpw)

{

	return DIV_ROUND_UP(bpw, BITS_PER_BYTE);

}



static bool spi_imx_can_dma(struct spi_master *master, struct spi_device *spi,

			 struct spi_transfer *transfer)

{

	struct spi_imx_data *spi_imx = spi_master_get_devdata(master);

	unsigned int bpw = transfer->bits_per_word;



	if (master->dma_rx && transfer->len >= spi_imx->wml &&

	    (transfer->len % spi_imx->wml) == 0)

		return true;

	if (!master->dma_rx)

		return false;



	if (!bpw)

		bpw = spi->bits_per_word;



	bpw = spi_imx_bytes_per_word(bpw);



	if (bpw != 1 && bpw != 2 && bpw != 4)

		return false;



	if (transfer->len < spi_imx->wml * bpw)

		return false;



	if (transfer->len % (spi_imx->wml * bpw))

		return false;



	return true;

}



#define MX51_ECSPI_CTRL		0x08
@@ -775,11 +799,63 @@ static irqreturn_t spi_imx_isr(int irq, void *dev_id) 
	return IRQ_HANDLED;

}



static int spi_imx_dma_configure(struct spi_master *master,

				 int bytes_per_word)

{

	int ret;

	enum dma_slave_buswidth buswidth;

	struct dma_slave_config rx = {}, tx = {};

	struct spi_imx_data *spi_imx = spi_master_get_devdata(master);



	if (bytes_per_word == spi_imx->bytes_per_word)

		/* Same as last time */

		return 0;



	switch (bytes_per_word) {

	case 4:

		buswidth = DMA_SLAVE_BUSWIDTH_4_BYTES;

		break;

	case 2:

		buswidth = DMA_SLAVE_BUSWIDTH_2_BYTES;

		break;

	case 1:

		buswidth = DMA_SLAVE_BUSWIDTH_1_BYTE;

		break;

	default:

		return -EINVAL;

	}



	tx.direction = DMA_MEM_TO_DEV;

	tx.dst_addr = spi_imx->base_phys + MXC_CSPITXDATA;

	tx.dst_addr_width = buswidth;

	tx.dst_maxburst = spi_imx->wml;

	ret = dmaengine_slave_config(master->dma_tx, &tx);

	if (ret) {

		dev_err(spi_imx->dev, "TX dma configuration failed with %d\n", ret);

		return ret;

	}



	rx.direction = DMA_DEV_TO_MEM;

	rx.src_addr = spi_imx->base_phys + MXC_CSPIRXDATA;

	rx.src_addr_width = buswidth;

	rx.src_maxburst = spi_imx->wml;

	ret = dmaengine_slave_config(master->dma_rx, &rx);

	if (ret) {

		dev_err(spi_imx->dev, "RX dma configuration failed with %d\n", ret);

		return ret;

	}



	spi_imx->bytes_per_word = bytes_per_word;



	return 0;

}



static int spi_imx_setupxfer(struct spi_device *spi,

				 struct spi_transfer *t)

{

	struct spi_imx_data *spi_imx = spi_master_get_devdata(spi->master);

	struct spi_imx_config config;

	int ret;



	config.bpw = t ? t->bits_per_word : spi->bits_per_word;

	config.speed_hz  = t ? t->speed_hz : spi->max_speed_hz;
@@ -808,6 +884,13 @@ static int spi_imx_setupxfer(struct spi_device *spi, 
	else

		spi_imx->usedma = 0;



	if (spi_imx->usedma) {

		ret = spi_imx_dma_configure(spi->master,

					    spi_imx_bytes_per_word(config.bpw));

		if (ret)

			return ret;

	}



	spi_imx->devtype_data->config(spi_imx, &config);



	return 0;
@@ -829,10 +912,8 @@ static void spi_imx_sdma_exit(struct spi_imx_data *spi_imx) 
}



static int spi_imx_sdma_init(struct device *dev, struct spi_imx_data *spi_imx,

			     struct spi_master *master,

			     const struct resource *res)

			     struct spi_master *master)

{

	struct dma_slave_config slave_config = {};

	int ret;



	/* use pio mode for i.mx6dl chip TKT238285 */
@@ -850,16 +931,6 @@ static int spi_imx_sdma_init(struct device *dev, struct spi_imx_data *spi_imx, 
		goto err;

	}



	slave_config.direction = DMA_MEM_TO_DEV;

	slave_config.dst_addr = res->start + MXC_CSPITXDATA;

	slave_config.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;

	slave_config.dst_maxburst = spi_imx->wml;

	ret = dmaengine_slave_config(master->dma_tx, &slave_config);

	if (ret) {

		dev_err(dev, "error in TX dma configuration.\n");

		goto err;

	}



	/* Prepare for RX : */

	master->dma_rx = dma_request_slave_channel_reason(dev, "rx");

	if (IS_ERR(master->dma_rx)) {
@@ -869,15 +940,7 @@ static int spi_imx_sdma_init(struct device *dev, struct spi_imx_data *spi_imx, 
		goto err;

	}



	slave_config.direction = DMA_DEV_TO_MEM;

	slave_config.src_addr = res->start + MXC_CSPIRXDATA;

	slave_config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;

	slave_config.src_maxburst = spi_imx->wml;

	ret = dmaengine_slave_config(master->dma_rx, &slave_config);

	if (ret) {

		dev_err(dev, "error in RX dma configuration.\n");

		goto err;

	}

	spi_imx_dma_configure(master, 1);



	init_completion(&spi_imx->dma_rx_completion);

	init_completion(&spi_imx->dma_tx_completion);
@@ -1164,6 +1227,7 @@ static int spi_imx_probe(struct platform_device *pdev) 
		ret = PTR_ERR(spi_imx->base);

		goto out_master_put;

	}

	spi_imx->base_phys = res->start;



	irq = platform_get_irq(pdev, 0);

	if (irq < 0) {
@@ -1204,7 +1268,7 @@ static int spi_imx_probe(struct platform_device *pdev) 
	 * other chips.

	 */

	if (is_imx51_ecspi(spi_imx)) {

		ret = spi_imx_sdma_init(&pdev->dev, spi_imx, master, res);

		ret = spi_imx_sdma_init(&pdev->dev, spi_imx, master);

		if (ret == -EPROBE_DEFER)

			goto out_clk_put;