1 files changed, 674 insertions, 0 deletions

diff --git a/drivers/spi/spi-mxs.c b/drivers/spi/spi-mxs.c
new file mode 100644
index 000000000000..edf1360ab09e
--- /dev/null
+++ b/drivers/spi/spi-mxs.c
@@ -0,0 +1,674 @@
+/*
+ * 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 <marex@denx.de>
+ *
+ * Based on previous attempt by:
+ * Fabio Estevam <fabio.estevam@freescale.com>
+ *
+ * Based on code from U-Boot bootloader by:
+ * Marek Vasut <marex@denx.de>
+ *
+ * Based on spi-stmp.c, which is:
+ * Author: Dmitry Pervushin <dimka@embeddedalley.com>
+ *
+ * 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_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 |= 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;
+		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 = 0;
+	spi_finalize_current_message(master);
+
+	return status;
+}
+
+static bool mxs_ssp_dma_filter(struct dma_chan *chan, void *param)
+{
+	struct mxs_ssp *ssp = param;
+
+	if (!mxs_dma_is_apbh(chan))
+		return false;
+
+	if (chan->chan_id != ssp->dma_channel)
+		return false;
+
+	chan->private = &ssp->dma_data;
+
+	return true;
+}
+
+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 __devinit 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, *dmares;
+	struct pinctrl *pinctrl;
+	struct clk *clk;
+	void __iomem *base;
+	int devid, dma_channel, clk_freq;
+	int ret = 0, irq_err, irq_dma;
+	dma_cap_mask_t mask;
+
+	/*
+	 * 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);
+	irq_dma = platform_get_irq(pdev, 1);
+	if (!iores || irq_err < 0 || irq_dma < 0)
+		return -EINVAL;
+
+	base = devm_request_and_ioremap(&pdev->dev, iores);
+	if (!base)
+		return -EADDRNOTAVAIL;
+
+	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);
+
+	if (np) {
+		devid = (enum mxs_ssp_id) of_id->data;
+		/*
+		 * TODO: This is a temporary solution and should be changed
+		 * to use generic DMA binding later when the helpers get in.
+		 */
+		ret = of_property_read_u32(np, "fsl,ssp-dma-channel",
+					   &dma_channel);
+		if (ret) {
+			dev_err(&pdev->dev,
+				"Failed to get DMA channel\n");
+			return -EINVAL;
+		}
+
+		ret = of_property_read_u32(np, "clock-frequency",
+					   &clk_freq);
+		if (ret)
+			clk_freq = clk_freq_default;
+	} else {
+		dmares = platform_get_resource(pdev, IORESOURCE_DMA, 0);
+		if (!dmares)
+			return -EINVAL;
+		devid = pdev->id_entry->driver_data;
+		dma_channel = dmares->start;
+		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;
+	ssp->dma_channel = dma_channel;
+
+	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;
+
+	dma_cap_zero(mask);
+	dma_cap_set(DMA_SLAVE, mask);
+	ssp->dma_data.chan_irq = irq_dma;
+	ssp->dmach = dma_request_channel(mask, mxs_ssp_dma_filter, ssp);
+	if (!ssp->dmach) {
+		dev_err(ssp->dev, "Failed to request DMA\n");
+		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 __devexit 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	= __devexit_p(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 <marex@denx.de>");
+MODULE_DESCRIPTION("MXS SPI master driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:mxs-spi");