[linux.git] / drivers / spi / spi-mxs.c

/*
 * Freescale MXS SPI master driver
 *
 * Copyright 2012 DENX Software Engineering, GmbH.
 * Copyright 2012 Freescale Semiconductor, Inc.
 * Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved.
 *
 * Rework and transition to new API by:
 * Marek Vasut <[email protected]>
 *
 * Based on previous attempt by:
 * Fabio Estevam <[email protected]>
 *
 * Based on code from U-Boot bootloader by:
 * Marek Vasut <[email protected]>
 *
 * Based on spi-stmp.c, which is:
 * Author: Dmitry Pervushin <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_gpio.h>
#include <linux/platform_device.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/highmem.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/completion.h>
#include <linux/gpio.h>
#include <linux/regulator/consumer.h>
#include <linux/module.h>
#include <linux/pinctrl/consumer.h>
#include <linux/stmp_device.h>
#include <linux/spi/spi.h>
#include <linux/spi/mxs-spi.h>

#define DRIVER_NAME		"mxs-spi"

/* Use 10S timeout for very long transfers, it should suffice. */
#define SSP_TIMEOUT		10000

#define SG_MAXLEN		0xff00

struct mxs_spi {
	struct mxs_ssp		ssp;
	struct completion	c;
};

static int mxs_spi_setup_transfer(struct spi_device *dev,
				struct spi_transfer *t)
{
	struct mxs_spi *spi = spi_master_get_devdata(dev->master);
	struct mxs_ssp *ssp = &spi->ssp;
	uint8_t bits_per_word;
	uint32_t hz = 0;

	bits_per_word = dev->bits_per_word;
	if (t && t->bits_per_word)
		bits_per_word = t->bits_per_word;

	if (bits_per_word != 8) {
		dev_err(&dev->dev, "%s, unsupported bits_per_word=%d\n",
					__func__, bits_per_word);
		return -EINVAL;
	}

	hz = dev->max_speed_hz;
	if (t && t->speed_hz)
		hz = min(hz, t->speed_hz);
	if (hz == 0) {
		dev_err(&dev->dev, "Cannot continue with zero clock\n");
		return -EINVAL;
	}

	mxs_ssp_set_clk_rate(ssp, hz);

	writel(BF_SSP_CTRL1_SSP_MODE(BV_SSP_CTRL1_SSP_MODE__SPI) |
		     BF_SSP_CTRL1_WORD_LENGTH
		     (BV_SSP_CTRL1_WORD_LENGTH__EIGHT_BITS) |
		     ((dev->mode & SPI_CPOL) ? BM_SSP_CTRL1_POLARITY : 0) |
		     ((dev->mode & SPI_CPHA) ? BM_SSP_CTRL1_PHASE : 0),
		     ssp->base + HW_SSP_CTRL1(ssp));

	writel(0x0, ssp->base + HW_SSP_CMD0);
	writel(0x0, ssp->base + HW_SSP_CMD1);

	return 0;
}

static int mxs_spi_setup(struct spi_device *dev)
{
	int err = 0;

	if (!dev->bits_per_word)
		dev->bits_per_word = 8;

	if (dev->mode & ~(SPI_CPOL | SPI_CPHA))
		return -EINVAL;

	err = mxs_spi_setup_transfer(dev, NULL);
	if (err) {
		dev_err(&dev->dev,
			"Failed to setup transfer, error = %d\n", err);
	}

	return err;
}

static uint32_t mxs_spi_cs_to_reg(unsigned cs)
{
	uint32_t select = 0;

	/*
	 * i.MX28 Datasheet: 17.10.1: HW_SSP_CTRL0
	 *
	 * The bits BM_SSP_CTRL0_WAIT_FOR_CMD and BM_SSP_CTRL0_WAIT_FOR_IRQ
	 * in HW_SSP_CTRL0 register do have multiple usage, please refer to
	 * the datasheet for further details. In SPI mode, they are used to
	 * toggle the chip-select lines (nCS pins).
	 */
	if (cs & 1)
		select |= BM_SSP_CTRL0_WAIT_FOR_CMD;
	if (cs & 2)
		select |= BM_SSP_CTRL0_WAIT_FOR_IRQ;

	return select;
}

static void mxs_spi_set_cs(struct mxs_spi *spi, unsigned cs)
{
	const uint32_t mask =
		BM_SSP_CTRL0_WAIT_FOR_CMD | BM_SSP_CTRL0_WAIT_FOR_IRQ;
	uint32_t select;
	struct mxs_ssp *ssp = &spi->ssp;

	writel(mask, ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_CLR);
	select = mxs_spi_cs_to_reg(cs);
	writel(select, ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);
}

static inline void mxs_spi_enable(struct mxs_spi *spi)
{
	struct mxs_ssp *ssp = &spi->ssp;

	writel(BM_SSP_CTRL0_LOCK_CS,
		ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);
	writel(BM_SSP_CTRL0_IGNORE_CRC,
		ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_CLR);
}

static inline void mxs_spi_disable(struct mxs_spi *spi)
{
	struct mxs_ssp *ssp = &spi->ssp;

	writel(BM_SSP_CTRL0_LOCK_CS,
		ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_CLR);
	writel(BM_SSP_CTRL0_IGNORE_CRC,
		ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);
}

static int mxs_ssp_wait(struct mxs_spi *spi, int offset, int mask, bool set)
{
	const unsigned long timeout = jiffies + msecs_to_jiffies(SSP_TIMEOUT);
	struct mxs_ssp *ssp = &spi->ssp;
	uint32_t reg;

	do {
		reg = readl_relaxed(ssp->base + offset);

		if (!set)
			reg = ~reg;

		reg &= mask;

		if (reg == mask)
			return 0;
	} while (time_before(jiffies, timeout));

	return -ETIMEDOUT;
}

static void mxs_ssp_dma_irq_callback(void *param)
{
	struct mxs_spi *spi = param;
	complete(&spi->c);
}

static irqreturn_t mxs_ssp_irq_handler(int irq, void *dev_id)
{
	struct mxs_ssp *ssp = dev_id;
	dev_err(ssp->dev, "%s[%i] CTRL1=%08x STATUS=%08x\n",
		__func__, __LINE__,
		readl(ssp->base + HW_SSP_CTRL1(ssp)),
		readl(ssp->base + HW_SSP_STATUS(ssp)));
	return IRQ_HANDLED;
}

static int mxs_spi_txrx_dma(struct mxs_spi *spi, int cs,
			    unsigned char *buf, int len,
			    int *first, int *last, int write)
{
	struct mxs_ssp *ssp = &spi->ssp;
	struct dma_async_tx_descriptor *desc = NULL;
	const bool vmalloced_buf = is_vmalloc_addr(buf);
	const int desc_len = vmalloced_buf ? PAGE_SIZE : SG_MAXLEN;
	const int sgs = DIV_ROUND_UP(len, desc_len);
	int sg_count;
	int min, ret;
	uint32_t ctrl0;
	struct page *vm_page;
	void *sg_buf;
	struct {
		uint32_t		pio[4];
		struct scatterlist	sg;
	} *dma_xfer;

	if (!len)
		return -EINVAL;

	dma_xfer = kzalloc(sizeof(*dma_xfer) * sgs, GFP_KERNEL);
	if (!dma_xfer)
		return -ENOMEM;

	INIT_COMPLETION(spi->c);

	ctrl0 = readl(ssp->base + HW_SSP_CTRL0);
	ctrl0 &= ~BM_SSP_CTRL0_XFER_COUNT;
	ctrl0 |= BM_SSP_CTRL0_DATA_XFER | mxs_spi_cs_to_reg(cs);

	if (*first)
		ctrl0 |= BM_SSP_CTRL0_LOCK_CS;
	if (!write)
		ctrl0 |= BM_SSP_CTRL0_READ;

	/* Queue the DMA data transfer. */
	for (sg_count = 0; sg_count < sgs; sg_count++) {
		min = min(len, desc_len);

		/* Prepare the transfer descriptor. */
		if ((sg_count + 1 == sgs) && *last)
			ctrl0 |= BM_SSP_CTRL0_IGNORE_CRC;

		if (ssp->devid == IMX23_SSP) {
			ctrl0 &= ~BM_SSP_CTRL0_XFER_COUNT;
			ctrl0 |= min;
		}

		dma_xfer[sg_count].pio[0] = ctrl0;
		dma_xfer[sg_count].pio[3] = min;

		if (vmalloced_buf) {
			vm_page = vmalloc_to_page(buf);
			if (!vm_page) {
				ret = -ENOMEM;
				goto err_vmalloc;
			}
			sg_buf = page_address(vm_page) +
				((size_t)buf & ~PAGE_MASK);
		} else {
			sg_buf = buf;
		}

		sg_init_one(&dma_xfer[sg_count].sg, sg_buf, min);
		ret = dma_map_sg(ssp->dev, &dma_xfer[sg_count].sg, 1,
			write ? DMA_TO_DEVICE : DMA_FROM_DEVICE);

		len -= min;
		buf += min;

		/* Queue the PIO register write transfer. */
		desc = dmaengine_prep_slave_sg(ssp->dmach,
				(struct scatterlist *)dma_xfer[sg_count].pio,
				(ssp->devid == IMX23_SSP) ? 1 : 4,
				DMA_TRANS_NONE,
				sg_count ? DMA_PREP_INTERRUPT : 0);
		if (!desc) {
			dev_err(ssp->dev,
				"Failed to get PIO reg. write descriptor.\n");
			ret = -EINVAL;
			goto err_mapped;
		}

		desc = dmaengine_prep_slave_sg(ssp->dmach,
				&dma_xfer[sg_count].sg, 1,
				write ? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM,
				DMA_PREP_INTERRUPT | DMA_CTRL_ACK);

		if (!desc) {
			dev_err(ssp->dev,
				"Failed to get DMA data write descriptor.\n");
			ret = -EINVAL;
			goto err_mapped;
		}
	}

	/*
	 * The last descriptor must have this callback,
	 * to finish the DMA transaction.
	 */
	desc->callback = mxs_ssp_dma_irq_callback;
	desc->callback_param = spi;

	/* Start the transfer. */
	dmaengine_submit(desc);
	dma_async_issue_pending(ssp->dmach);

	ret = wait_for_completion_timeout(&spi->c,
				msecs_to_jiffies(SSP_TIMEOUT));
	if (!ret) {
		dev_err(ssp->dev, "DMA transfer timeout\n");
		ret = -ETIMEDOUT;
		dmaengine_terminate_all(ssp->dmach);
		goto err_vmalloc;
	}

	ret = 0;

err_vmalloc:
	while (--sg_count >= 0) {
err_mapped:
		dma_unmap_sg(ssp->dev, &dma_xfer[sg_count].sg, 1,
			write ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
	}

	kfree(dma_xfer);

	return ret;
}

static int mxs_spi_txrx_pio(struct mxs_spi *spi, int cs,
			    unsigned char *buf, int len,
			    int *first, int *last, int write)
{
	struct mxs_ssp *ssp = &spi->ssp;

	if (*first)
		mxs_spi_enable(spi);

	mxs_spi_set_cs(spi, cs);

	while (len--) {
		if (*last && len == 0)
			mxs_spi_disable(spi);

		if (ssp->devid == IMX23_SSP) {
			writel(BM_SSP_CTRL0_XFER_COUNT,
				ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_CLR);
			writel(1,
				ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);
		} else {
			writel(1, ssp->base + HW_SSP_XFER_SIZE);
		}

		if (write)
			writel(BM_SSP_CTRL0_READ,
				ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_CLR);
		else
			writel(BM_SSP_CTRL0_READ,
				ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);

		writel(BM_SSP_CTRL0_RUN,
				ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);

		if (mxs_ssp_wait(spi, HW_SSP_CTRL0, BM_SSP_CTRL0_RUN, 1))
			return -ETIMEDOUT;

		if (write)
			writel(*buf, ssp->base + HW_SSP_DATA(ssp));

		writel(BM_SSP_CTRL0_DATA_XFER,
			     ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);

		if (!write) {
			if (mxs_ssp_wait(spi, HW_SSP_STATUS(ssp),
						BM_SSP_STATUS_FIFO_EMPTY, 0))
				return -ETIMEDOUT;

			*buf = (readl(ssp->base + HW_SSP_DATA(ssp)) & 0xff);
		}

		if (mxs_ssp_wait(spi, HW_SSP_CTRL0, BM_SSP_CTRL0_RUN, 0))
			return -ETIMEDOUT;

		buf++;
	}

	if (len <= 0)
		return 0;

	return -ETIMEDOUT;
}

static int mxs_spi_transfer_one(struct spi_master *master,
				struct spi_message *m)
{
	struct mxs_spi *spi = spi_master_get_devdata(master);
	struct mxs_ssp *ssp = &spi->ssp;
	int first, last;
	struct spi_transfer *t, *tmp_t;
	int status = 0;
	int cs;

	first = last = 0;

	cs = m->spi->chip_select;

	list_for_each_entry_safe(t, tmp_t, &m->transfers, transfer_list) {

		status = mxs_spi_setup_transfer(m->spi, t);
		if (status)
			break;

		if (&t->transfer_list == m->transfers.next)
			first = 1;
		if (&t->transfer_list == m->transfers.prev)
			last = 1;
		if ((t->rx_buf && t->tx_buf) || (t->rx_dma && t->tx_dma)) {
			dev_err(ssp->dev,
				"Cannot send and receive simultaneously\n");
			status = -EINVAL;
			break;
		}

		/*
		 * Small blocks can be transfered via PIO.
		 * Measured by empiric means:
		 *
		 * dd if=/dev/mtdblock0 of=/dev/null bs=1024k count=1
		 *
		 * DMA only: 2.164808 seconds, 473.0KB/s
		 * Combined: 1.676276 seconds, 610.9KB/s
		 */
		if (t->len < 32) {
			writel(BM_SSP_CTRL1_DMA_ENABLE,
				ssp->base + HW_SSP_CTRL1(ssp) +
				STMP_OFFSET_REG_CLR);

			if (t->tx_buf)
				status = mxs_spi_txrx_pio(spi, cs,
						(void *)t->tx_buf,
						t->len, &first, &last, 1);
			if (t->rx_buf)
				status = mxs_spi_txrx_pio(spi, cs,
						t->rx_buf, t->len,
						&first, &last, 0);
		} else {
			writel(BM_SSP_CTRL1_DMA_ENABLE,
				ssp->base + HW_SSP_CTRL1(ssp) +
				STMP_OFFSET_REG_SET);

			if (t->tx_buf)
				status = mxs_spi_txrx_dma(spi, cs,
						(void *)t->tx_buf, t->len,
						&first, &last, 1);
			if (t->rx_buf)
				status = mxs_spi_txrx_dma(spi, cs,
						t->rx_buf, t->len,
						&first, &last, 0);
		}

		if (status) {
			stmp_reset_block(ssp->base);
			break;
		}

		m->actual_length += t->len;
		first = last = 0;
	}

	m->status = status;
	spi_finalize_current_message(master);

	return status;
}

static const struct of_device_id mxs_spi_dt_ids[] = {
	{ .compatible = "fsl,imx23-spi", .data = (void *) IMX23_SSP, },
	{ .compatible = "fsl,imx28-spi", .data = (void *) IMX28_SSP, },
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, mxs_spi_dt_ids);

static int mxs_spi_probe(struct platform_device *pdev)
{
	const struct of_device_id *of_id =
			of_match_device(mxs_spi_dt_ids, &pdev->dev);
	struct device_node *np = pdev->dev.of_node;
	struct spi_master *master;
	struct mxs_spi *spi;
	struct mxs_ssp *ssp;
	struct resource *iores;
	struct pinctrl *pinctrl;
	struct clk *clk;
	void __iomem *base;
	int devid, clk_freq;
	int ret = 0, irq_err;

	/*
	 * Default clock speed for the SPI core. 160MHz seems to
	 * work reasonably well with most SPI flashes, so use this
	 * as a default. Override with "clock-frequency" DT prop.
	 */
	const int clk_freq_default = 160000000;

	iores = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	irq_err = platform_get_irq(pdev, 0);
	if (!iores || irq_err < 0)
		return -EINVAL;

	base = devm_ioremap_resource(&pdev->dev, iores);
	if (IS_ERR(base))
		return PTR_ERR(base);

	pinctrl = devm_pinctrl_get_select_default(&pdev->dev);
	if (IS_ERR(pinctrl))
		return PTR_ERR(pinctrl);

	clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(clk))
		return PTR_ERR(clk);

	devid = (enum mxs_ssp_id) of_id->data;
	ret = of_property_read_u32(np, "clock-frequency",
				   &clk_freq);
	if (ret)
		clk_freq = clk_freq_default;

	master = spi_alloc_master(&pdev->dev, sizeof(*spi));
	if (!master)
		return -ENOMEM;

	master->transfer_one_message = mxs_spi_transfer_one;
	master->setup = mxs_spi_setup;
	master->mode_bits = SPI_CPOL | SPI_CPHA;
	master->num_chipselect = 3;
	master->dev.of_node = np;
	master->flags = SPI_MASTER_HALF_DUPLEX;

	spi = spi_master_get_devdata(master);
	ssp = &spi->ssp;
	ssp->dev = &pdev->dev;
	ssp->clk = clk;
	ssp->base = base;
	ssp->devid = devid;

	init_completion(&spi->c);

	ret = devm_request_irq(&pdev->dev, irq_err, mxs_ssp_irq_handler, 0,
			       DRIVER_NAME, ssp);
	if (ret)
		goto out_master_free;

	ssp->dmach = dma_request_slave_channel(&pdev->dev, "rx-tx");
	if (!ssp->dmach) {
		dev_err(ssp->dev, "Failed to request DMA\n");
		ret = -ENODEV;
		goto out_master_free;
	}

	clk_prepare_enable(ssp->clk);
	clk_set_rate(ssp->clk, clk_freq);
	ssp->clk_rate = clk_get_rate(ssp->clk) / 1000;

	stmp_reset_block(ssp->base);

	platform_set_drvdata(pdev, master);

	ret = spi_register_master(master);
	if (ret) {
		dev_err(&pdev->dev, "Cannot register SPI master, %d\n", ret);
		goto out_free_dma;
	}

	return 0;

out_free_dma:
	dma_release_channel(ssp->dmach);
	clk_disable_unprepare(ssp->clk);
out_master_free:
	spi_master_put(master);
	return ret;
}

static int mxs_spi_remove(struct platform_device *pdev)
{
	struct spi_master *master;
	struct mxs_spi *spi;
	struct mxs_ssp *ssp;

	master = spi_master_get(platform_get_drvdata(pdev));
	spi = spi_master_get_devdata(master);
	ssp = &spi->ssp;

	spi_unregister_master(master);

	dma_release_channel(ssp->dmach);

	clk_disable_unprepare(ssp->clk);

	spi_master_put(master);

	return 0;
}

static struct platform_driver mxs_spi_driver = {
	.probe	= mxs_spi_probe,
	.remove	= mxs_spi_remove,
	.driver	= {
		.name	= DRIVER_NAME,
		.owner	= THIS_MODULE,
		.of_match_table = mxs_spi_dt_ids,
	},
};

module_platform_driver(mxs_spi_driver);

MODULE_AUTHOR("Marek Vasut <[email protected]>");
MODULE_DESCRIPTION("MXS SPI master driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:mxs-spi");
Commit	Line	Data
646781d3 MV	1	/*
	2	* Freescale MXS SPI master driver
	3	*
	4	* Copyright 2012 DENX Software Engineering, GmbH.
	5	* Copyright 2012 Freescale Semiconductor, Inc.
	6	* Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved.
	7	*
	8	* Rework and transition to new API by:
	9	* Marek Vasut <[email protected]>
	10	*
	11	* Based on previous attempt by:
	12	* Fabio Estevam <[email protected]>
	13	*
	14	* Based on code from U-Boot bootloader by:
	15	* Marek Vasut <[email protected]>
	16	*
	17	* Based on spi-stmp.c, which is:
	18	* Author: Dmitry Pervushin <[email protected]>
	19	*
	20	* This program is free software; you can redistribute it and/or modify
	21	* it under the terms of the GNU General Public License as published by
	22	* the Free Software Foundation; either version 2 of the License, or
	23	* (at your option) any later version.
	24	*
	25	* This program is distributed in the hope that it will be useful,
	26	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	27	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	28	* GNU General Public License for more details.
	29	*/
	30
	31	#include <linux/kernel.h>
	32	#include <linux/init.h>
	33	#include <linux/ioport.h>
	34	#include <linux/of.h>
	35	#include <linux/of_device.h>
	36	#include <linux/of_gpio.h>
	37	#include <linux/platform_device.h>
	38	#include <linux/delay.h>
	39	#include <linux/interrupt.h>
	40	#include <linux/dma-mapping.h>
	41	#include <linux/dmaengine.h>
	42	#include <linux/highmem.h>
	43	#include <linux/clk.h>
	44	#include <linux/err.h>
	45	#include <linux/completion.h>
	46	#include <linux/gpio.h>
	47	#include <linux/regulator/consumer.h>
	48	#include <linux/module.h>
646781d3 MV	49	#include <linux/pinctrl/consumer.h>
	50	#include <linux/stmp_device.h>
	51	#include <linux/spi/spi.h>
	52	#include <linux/spi/mxs-spi.h>
	53
	54	#define DRIVER_NAME "mxs-spi"
	55
010b4818 MV	56	/* Use 10S timeout for very long transfers, it should suffice. */
010b4818 MV	57	#define SSP_TIMEOUT 10000
646781d3	58
474afc04 MV	59	#define SG_MAXLEN 0xff00
474afc04 MV	60
646781d3 MV	61	struct mxs_spi {
646781d3 MV	62	struct mxs_ssp ssp;
474afc04	63	struct completion c;
646781d3 MV	64	};
	65
	66	static int mxs_spi_setup_transfer(struct spi_device *dev,
	67	struct spi_transfer *t)
	68	{
	69	struct mxs_spi *spi = spi_master_get_devdata(dev->master);
	70	struct mxs_ssp *ssp = &spi->ssp;
	71	uint8_t bits_per_word;
	72	uint32_t hz = 0;
	73
	74	bits_per_word = dev->bits_per_word;
	75	if (t && t->bits_per_word)
	76	bits_per_word = t->bits_per_word;
	77
	78	if (bits_per_word != 8) {
	79	dev_err(&dev->dev, "%s, unsupported bits_per_word=%d\n",
	80	__func__, bits_per_word);
	81	return -EINVAL;
	82	}
	83
	84	hz = dev->max_speed_hz;
	85	if (t && t->speed_hz)
	86	hz = min(hz, t->speed_hz);
	87	if (hz == 0) {
	88	dev_err(&dev->dev, "Cannot continue with zero clock\n");
	89	return -EINVAL;
	90	}
	91
	92	mxs_ssp_set_clk_rate(ssp, hz);
	93
	94	writel(BF_SSP_CTRL1_SSP_MODE(BV_SSP_CTRL1_SSP_MODE__SPI) \|
	95	BF_SSP_CTRL1_WORD_LENGTH
	96	(BV_SSP_CTRL1_WORD_LENGTH__EIGHT_BITS) \|
	97	((dev->mode & SPI_CPOL) ? BM_SSP_CTRL1_POLARITY : 0) \|
	98	((dev->mode & SPI_CPHA) ? BM_SSP_CTRL1_PHASE : 0),
	99	ssp->base + HW_SSP_CTRL1(ssp));
	100
	101	writel(0x0, ssp->base + HW_SSP_CMD0);
	102	writel(0x0, ssp->base + HW_SSP_CMD1);
	103
	104	return 0;
	105	}
	106
	107	static int mxs_spi_setup(struct spi_device *dev)
	108	{
	109	int err = 0;
	110
	111	if (!dev->bits_per_word)
	112	dev->bits_per_word = 8;
	113
	114	if (dev->mode & ~(SPI_CPOL \| SPI_CPHA))
	115	return -EINVAL;
	116
	117	err = mxs_spi_setup_transfer(dev, NULL);
	118	if (err) {
	119	dev_err(&dev->dev,
	120	"Failed to setup transfer, error = %d\n", err);
	121	}
	122
	123	return err;
	124	}
	125
	126	static uint32_t mxs_spi_cs_to_reg(unsigned cs)
	127	{
128	uint32_t select = 0;
129
130	/*
131	* i.MX28 Datasheet: 17.10.1: HW_SSP_CTRL0
132	*
133	* The bits BM_SSP_CTRL0_WAIT_FOR_CMD and BM_SSP_CTRL0_WAIT_FOR_IRQ
134	* in HW_SSP_CTRL0 register do have multiple usage, please refer to
135	* the datasheet for further details. In SPI mode, they are used to
136	* toggle the chip-select lines (nCS pins).
137	*/
138	if (cs & 1)
139	select \|= BM_SSP_CTRL0_WAIT_FOR_CMD;
140	if (cs & 2)
141	select \|= BM_SSP_CTRL0_WAIT_FOR_IRQ;
142
143	return select;
144	}
145
146	static void mxs_spi_set_cs(struct mxs_spi *spi, unsigned cs)
147	{
148	const uint32_t mask =
149	BM_SSP_CTRL0_WAIT_FOR_CMD \| BM_SSP_CTRL0_WAIT_FOR_IRQ;
150	uint32_t select;
151	struct mxs_ssp *ssp = &spi->ssp;
152
153	writel(mask, ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_CLR);
154	select = mxs_spi_cs_to_reg(cs);
155	writel(select, ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);
156	}
157
158	static inline void mxs_spi_enable(struct mxs_spi *spi)
159	{
160	struct mxs_ssp *ssp = &spi->ssp;
161
162	writel(BM_SSP_CTRL0_LOCK_CS,
163	ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);
164	writel(BM_SSP_CTRL0_IGNORE_CRC,
165	ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_CLR);
166	}
167
168	static inline void mxs_spi_disable(struct mxs_spi *spi)
169	{
170	struct mxs_ssp *ssp = &spi->ssp;
171
172	writel(BM_SSP_CTRL0_LOCK_CS,
173	ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_CLR);
174	writel(BM_SSP_CTRL0_IGNORE_CRC,
175	ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);
176	}
177
178	static int mxs_ssp_wait(struct mxs_spi *spi, int offset, int mask, bool set)
179	{
f13639dc	180	const unsigned long timeout = jiffies + msecs_to_jiffies(SSP_TIMEOUT);
646781d3 MV	181	struct mxs_ssp *ssp = &spi->ssp;
	182	uint32_t reg;
	183
f13639dc	184	do {
646781d3 MV	185	reg = readl_relaxed(ssp->base + offset);
646781d3 MV	186
f13639dc MV	187	if (!set)
f13639dc MV	188	reg = ~reg;
646781d3	189
f13639dc	190	reg &= mask;
646781d3	191
f13639dc MV	192	if (reg == mask)
	193	return 0;
	194	} while (time_before(jiffies, timeout));
646781d3	195
f13639dc	196	return -ETIMEDOUT;
646781d3 MV	197	}
646781d3 MV	198
474afc04 MV	199	static void mxs_ssp_dma_irq_callback(void *param)
	200	{
	201	struct mxs_spi *spi = param;
	202	complete(&spi->c);
	203	}
	204
	205	static irqreturn_t mxs_ssp_irq_handler(int irq, void *dev_id)
	206	{
	207	struct mxs_ssp *ssp = dev_id;
	208	dev_err(ssp->dev, "%s[%i] CTRL1=%08x STATUS=%08x\n",
	209	__func__, __LINE__,
	210	readl(ssp->base + HW_SSP_CTRL1(ssp)),
	211	readl(ssp->base + HW_SSP_STATUS(ssp)));
	212	return IRQ_HANDLED;
	213	}
	214
	215	static int mxs_spi_txrx_dma(struct mxs_spi *spi, int cs,
	216	unsigned char *buf, int len,
	217	int first, int last, int write)
	218	{
	219	struct mxs_ssp *ssp = &spi->ssp;
010b4818 MV	220	struct dma_async_tx_descriptor *desc = NULL;
	221	const bool vmalloced_buf = is_vmalloc_addr(buf);
	222	const int desc_len = vmalloced_buf ? PAGE_SIZE : SG_MAXLEN;
	223	const int sgs = DIV_ROUND_UP(len, desc_len);
474afc04	224	int sg_count;
010b4818 MV	225	int min, ret;
	226	uint32_t ctrl0;
	227	struct page *vm_page;
	228	void *sg_buf;
	229	struct {
	230	uint32_t pio[4];
	231	struct scatterlist sg;
	232	} *dma_xfer;
	233
	234	if (!len)
474afc04	235	return -EINVAL;
010b4818 MV	236
	237	dma_xfer = kzalloc(sizeof(dma_xfer) sgs, GFP_KERNEL);
	238	if (!dma_xfer)
	239	return -ENOMEM;
474afc04	240
41682e03	241	INIT_COMPLETION(spi->c);
474afc04	242
010b4818	243	ctrl0 = readl(ssp->base + HW_SSP_CTRL0);
ba486a2a	244	ctrl0 &= ~BM_SSP_CTRL0_XFER_COUNT;
010b4818 MV	245	ctrl0 \|= BM_SSP_CTRL0_DATA_XFER \| mxs_spi_cs_to_reg(cs);
010b4818 MV	246
474afc04	247	if (*first)
010b4818	248	ctrl0 \|= BM_SSP_CTRL0_LOCK_CS;
474afc04	249	if (!write)
010b4818	250	ctrl0 \|= BM_SSP_CTRL0_READ;
474afc04 MV	251
474afc04 MV	252	/* Queue the DMA data transfer. */
010b4818 MV	253	for (sg_count = 0; sg_count < sgs; sg_count++) {
	254	min = min(len, desc_len);
	255
	256	/* Prepare the transfer descriptor. */
	257	if ((sg_count + 1 == sgs) && *last)
	258	ctrl0 \|= BM_SSP_CTRL0_IGNORE_CRC;
	259
ba486a2a JL	260	if (ssp->devid == IMX23_SSP) {
ba486a2a JL	261	ctrl0 &= ~BM_SSP_CTRL0_XFER_COUNT;
010b4818	262	ctrl0 \|= min;
ba486a2a	263	}
010b4818 MV	264
	265	dma_xfer[sg_count].pio[0] = ctrl0;
	266	dma_xfer[sg_count].pio[3] = min;
	267
	268	if (vmalloced_buf) {
	269	vm_page = vmalloc_to_page(buf);
	270	if (!vm_page) {
	271	ret = -ENOMEM;
	272	goto err_vmalloc;
	273	}
	274	sg_buf = page_address(vm_page) +
	275	((size_t)buf & ~PAGE_MASK);
	276	} else {
	277	sg_buf = buf;
	278	}
	279
	280	sg_init_one(&dma_xfer[sg_count].sg, sg_buf, min);
	281	ret = dma_map_sg(ssp->dev, &dma_xfer[sg_count].sg, 1,
	282	write ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
	283
	284	len -= min;
	285	buf += min;
	286
	287	/* Queue the PIO register write transfer. */
	288	desc = dmaengine_prep_slave_sg(ssp->dmach,
	289	(struct scatterlist *)dma_xfer[sg_count].pio,
	290	(ssp->devid == IMX23_SSP) ? 1 : 4,
	291	DMA_TRANS_NONE,
	292	sg_count ? DMA_PREP_INTERRUPT : 0);
	293	if (!desc) {
	294	dev_err(ssp->dev,
	295	"Failed to get PIO reg. write descriptor.\n");
	296	ret = -EINVAL;
	297	goto err_mapped;
	298	}
	299
	300	desc = dmaengine_prep_slave_sg(ssp->dmach,
	301	&dma_xfer[sg_count].sg, 1,
	302	write ? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM,
	303	DMA_PREP_INTERRUPT \| DMA_CTRL_ACK);
	304
	305	if (!desc) {
	306	dev_err(ssp->dev,
	307	"Failed to get DMA data write descriptor.\n");
	308	ret = -EINVAL;
	309	goto err_mapped;
	310	}
474afc04 MV	311	}
	312
	313	/*
	314	* The last descriptor must have this callback,
	315	* to finish the DMA transaction.
	316	*/
	317	desc->callback = mxs_ssp_dma_irq_callback;
	318	desc->callback_param = spi;
	319
	320	/* Start the transfer. */
	321	dmaengine_submit(desc);
	322	dma_async_issue_pending(ssp->dmach);
	323
	324	ret = wait_for_completion_timeout(&spi->c,
	325	msecs_to_jiffies(SSP_TIMEOUT));
474afc04 MV	326	if (!ret) {
	327	dev_err(ssp->dev, "DMA transfer timeout\n");
	328	ret = -ETIMEDOUT;
44968466	329	dmaengine_terminate_all(ssp->dmach);
010b4818	330	goto err_vmalloc;
474afc04 MV	331	}
	332
	333	ret = 0;
	334
010b4818 MV	335	err_vmalloc:
	336	while (--sg_count >= 0) {
	337	err_mapped:
	338	dma_unmap_sg(ssp->dev, &dma_xfer[sg_count].sg, 1,
474afc04 MV	339	write ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
	340	}
	341
010b4818 MV	342	kfree(dma_xfer);
010b4818 MV	343
474afc04 MV	344	return ret;
	345	}
	346
646781d3 MV	347	static int mxs_spi_txrx_pio(struct mxs_spi *spi, int cs,
	348	unsigned char *buf, int len,
	349	int first, int last, int write)
	350	{
	351	struct mxs_ssp *ssp = &spi->ssp;
	352
	353	if (*first)
	354	mxs_spi_enable(spi);
	355
	356	mxs_spi_set_cs(spi, cs);
	357
	358	while (len--) {
	359	if (*last && len == 0)
	360	mxs_spi_disable(spi);
	361
	362	if (ssp->devid == IMX23_SSP) {
	363	writel(BM_SSP_CTRL0_XFER_COUNT,
	364	ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_CLR);
	365	writel(1,
	366	ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);
	367	} else {
	368	writel(1, ssp->base + HW_SSP_XFER_SIZE);
	369	}
	370
	371	if (write)
	372	writel(BM_SSP_CTRL0_READ,
	373	ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_CLR);
	374	else
	375	writel(BM_SSP_CTRL0_READ,
	376	ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);
	377
	378	writel(BM_SSP_CTRL0_RUN,
	379	ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);
	380
	381	if (mxs_ssp_wait(spi, HW_SSP_CTRL0, BM_SSP_CTRL0_RUN, 1))
	382	return -ETIMEDOUT;
	383
	384	if (write)
	385	writel(*buf, ssp->base + HW_SSP_DATA(ssp));
	386
	387	writel(BM_SSP_CTRL0_DATA_XFER,
	388	ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);
	389
	390	if (!write) {
	391	if (mxs_ssp_wait(spi, HW_SSP_STATUS(ssp),
	392	BM_SSP_STATUS_FIFO_EMPTY, 0))
	393	return -ETIMEDOUT;
	394
	395	*buf = (readl(ssp->base + HW_SSP_DATA(ssp)) & 0xff);
	396	}
	397
	398	if (mxs_ssp_wait(spi, HW_SSP_CTRL0, BM_SSP_CTRL0_RUN, 0))
	399	return -ETIMEDOUT;
	400
	401	buf++;
	402	}
	403
	404	if (len <= 0)
	405	return 0;
	406
	407	return -ETIMEDOUT;
	408	}
	409
	410	static int mxs_spi_transfer_one(struct spi_master *master,
411	struct spi_message *m)
412	{
413	struct mxs_spi *spi = spi_master_get_devdata(master);
414	struct mxs_ssp *ssp = &spi->ssp;
415	int first, last;
416	struct spi_transfer t, tmp_t;
417	int status = 0;
418	int cs;
419
420	first = last = 0;
421
422	cs = m->spi->chip_select;
423
424	list_for_each_entry_safe(t, tmp_t, &m->transfers, transfer_list) {
425
426	status = mxs_spi_setup_transfer(m->spi, t);
427	if (status)
428	break;
429
430	if (&t->transfer_list == m->transfers.next)
431	first = 1;
432	if (&t->transfer_list == m->transfers.prev)
433	last = 1;
474afc04	434	if ((t->rx_buf && t->tx_buf) \|\| (t->rx_dma && t->tx_dma)) {
646781d3 MV	435	dev_err(ssp->dev,
	436	"Cannot send and receive simultaneously\n");
	437	status = -EINVAL;
	438	break;
	439	}
	440
474afc04 MV	441	/*
	442	* Small blocks can be transfered via PIO.
	443	* Measured by empiric means:
	444	*
	445	* dd if=/dev/mtdblock0 of=/dev/null bs=1024k count=1
	446	*
	447	* DMA only: 2.164808 seconds, 473.0KB/s
	448	* Combined: 1.676276 seconds, 610.9KB/s
	449	*/
727c10e3	450	if (t->len < 32) {
474afc04 MV	451	writel(BM_SSP_CTRL1_DMA_ENABLE,
	452	ssp->base + HW_SSP_CTRL1(ssp) +
	453	STMP_OFFSET_REG_CLR);
	454
	455	if (t->tx_buf)
	456	status = mxs_spi_txrx_pio(spi, cs,
	457	(void *)t->tx_buf,
	458	t->len, &first, &last, 1);
	459	if (t->rx_buf)
	460	status = mxs_spi_txrx_pio(spi, cs,
	461	t->rx_buf, t->len,
	462	&first, &last, 0);
	463	} else {
	464	writel(BM_SSP_CTRL1_DMA_ENABLE,
	465	ssp->base + HW_SSP_CTRL1(ssp) +
	466	STMP_OFFSET_REG_SET);
	467
	468	if (t->tx_buf)
	469	status = mxs_spi_txrx_dma(spi, cs,
	470	(void *)t->tx_buf, t->len,
	471	&first, &last, 1);
	472	if (t->rx_buf)
	473	status = mxs_spi_txrx_dma(spi, cs,
	474	t->rx_buf, t->len,
	475	&first, &last, 0);
	476	}
646781d3	477
c895db0f MV	478	if (status) {
c895db0f MV	479	stmp_reset_block(ssp->base);
646781d3	480	break;
c895db0f	481	}
646781d3	482
204e706f	483	m->actual_length += t->len;
646781d3 MV	484	first = last = 0;
	485	}
	486
d856f1eb	487	m->status = status;
646781d3 MV	488	spi_finalize_current_message(master);
	489
	490	return status;
	491	}
	492
	493	static const struct of_device_id mxs_spi_dt_ids[] = {
	494	{ .compatible = "fsl,imx23-spi", .data = (void *) IMX23_SSP, },
	495	{ .compatible = "fsl,imx28-spi", .data = (void *) IMX28_SSP, },
	496	{ /* sentinel */ }
	497	};
	498	MODULE_DEVICE_TABLE(of, mxs_spi_dt_ids);
	499
fd4a319b	500	static int mxs_spi_probe(struct platform_device *pdev)
646781d3 MV	501	{
	502	const struct of_device_id *of_id =
	503	of_match_device(mxs_spi_dt_ids, &pdev->dev);
	504	struct device_node *np = pdev->dev.of_node;
	505	struct spi_master *master;
	506	struct mxs_spi *spi;
	507	struct mxs_ssp *ssp;
26aafa77	508	struct resource *iores;
646781d3 MV	509	struct pinctrl *pinctrl;
	510	struct clk *clk;
	511	void __iomem *base;
26aafa77 SG	512	int devid, clk_freq;
26aafa77 SG	513	int ret = 0, irq_err;
646781d3	514
e64d07a2 MV	515	/*
	516	* Default clock speed for the SPI core. 160MHz seems to
	517	* work reasonably well with most SPI flashes, so use this
	518	* as a default. Override with "clock-frequency" DT prop.
	519	*/
	520	const int clk_freq_default = 160000000;
	521
646781d3	522	iores = platform_get_resource(pdev, IORESOURCE_MEM, 0);
474afc04	523	irq_err = platform_get_irq(pdev, 0);
26aafa77	524	if (!iores \|\| irq_err < 0)
646781d3 MV	525	return -EINVAL;
646781d3 MV	526
b0ee5605 TR	527	base = devm_ioremap_resource(&pdev->dev, iores);
	528	if (IS_ERR(base))
	529	return PTR_ERR(base);
646781d3 MV	530
	531	pinctrl = devm_pinctrl_get_select_default(&pdev->dev);
	532	if (IS_ERR(pinctrl))
	533	return PTR_ERR(pinctrl);
	534
	535	clk = devm_clk_get(&pdev->dev, NULL);
	536	if (IS_ERR(clk))
	537	return PTR_ERR(clk);
	538
26aafa77 SG	539	devid = (enum mxs_ssp_id) of_id->data;
	540	ret = of_property_read_u32(np, "clock-frequency",
	541	&clk_freq);
	542	if (ret)
e64d07a2	543	clk_freq = clk_freq_default;
646781d3 MV	544
	545	master = spi_alloc_master(&pdev->dev, sizeof(*spi));
	546	if (!master)
	547	return -ENOMEM;
	548
	549	master->transfer_one_message = mxs_spi_transfer_one;
	550	master->setup = mxs_spi_setup;
	551	master->mode_bits = SPI_CPOL \| SPI_CPHA;
	552	master->num_chipselect = 3;
	553	master->dev.of_node = np;
	554	master->flags = SPI_MASTER_HALF_DUPLEX;
	555
	556	spi = spi_master_get_devdata(master);
	557	ssp = &spi->ssp;
	558	ssp->dev = &pdev->dev;
	559	ssp->clk = clk;
	560	ssp->base = base;
	561	ssp->devid = devid;
474afc04	562
41682e03 MV	563	init_completion(&spi->c);
41682e03 MV	564
474afc04 MV	565	ret = devm_request_irq(&pdev->dev, irq_err, mxs_ssp_irq_handler, 0,
	566	DRIVER_NAME, ssp);
	567	if (ret)
	568	goto out_master_free;
	569
26aafa77	570	ssp->dmach = dma_request_slave_channel(&pdev->dev, "rx-tx");
474afc04 MV	571	if (!ssp->dmach) {
474afc04 MV	572	dev_err(ssp->dev, "Failed to request DMA\n");
58ad60bb	573	ret = -ENODEV;
474afc04 MV	574	goto out_master_free;
474afc04 MV	575	}
646781d3 MV	576
646781d3 MV	577	clk_prepare_enable(ssp->clk);
e64d07a2	578	clk_set_rate(ssp->clk, clk_freq);
646781d3 MV	579	ssp->clk_rate = clk_get_rate(ssp->clk) / 1000;
	580
	581	stmp_reset_block(ssp->base);
	582
	583	platform_set_drvdata(pdev, master);
	584
	585	ret = spi_register_master(master);
	586	if (ret) {
	587	dev_err(&pdev->dev, "Cannot register SPI master, %d\n", ret);
474afc04	588	goto out_free_dma;
646781d3 MV	589	}
	590
	591	return 0;
	592
474afc04	593	out_free_dma:
474afc04	594	dma_release_channel(ssp->dmach);
646781d3	595	clk_disable_unprepare(ssp->clk);
474afc04	596	out_master_free:
646781d3 MV	597	spi_master_put(master);
	598	return ret;
	599	}
	600
fd4a319b	601	static int mxs_spi_remove(struct platform_device *pdev)
646781d3 MV	602	{
	603	struct spi_master *master;
	604	struct mxs_spi *spi;
	605	struct mxs_ssp *ssp;
	606
7d520d28	607	master = spi_master_get(platform_get_drvdata(pdev));
646781d3 MV	608	spi = spi_master_get_devdata(master);
	609	ssp = &spi->ssp;
	610
	611	spi_unregister_master(master);
	612
474afc04 MV	613	dma_release_channel(ssp->dmach);
474afc04 MV	614
646781d3 MV	615	clk_disable_unprepare(ssp->clk);
	616
	617	spi_master_put(master);
	618
	619	return 0;
	620	}
	621
	622	static struct platform_driver mxs_spi_driver = {
	623	.probe = mxs_spi_probe,
fd4a319b	624	.remove = mxs_spi_remove,
646781d3 MV	625	.driver = {
	626	.name = DRIVER_NAME,
	627	.owner = THIS_MODULE,
	628	.of_match_table = mxs_spi_dt_ids,
	629	},
	630	};
	631
	632	module_platform_driver(mxs_spi_driver);
	633
	634	MODULE_AUTHOR("Marek Vasut <[email protected]>");
	635	MODULE_DESCRIPTION("MXS SPI master driver");
	636	MODULE_LICENSE("GPL");
	637	MODULE_ALIAS("platform:mxs-spi");