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path: root/drivers/spi/spi-mxs.c
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Diffstat (limited to 'drivers/spi/spi-mxs.c')
-rw-r--r--drivers/spi/spi-mxs.c583
1 files changed, 583 insertions, 0 deletions
diff --git a/drivers/spi/spi-mxs.c b/drivers/spi/spi-mxs.c
new file mode 100644
index 000000000..5b0e9a3e8
--- /dev/null
+++ b/drivers/spi/spi-mxs.c
@@ -0,0 +1,583 @@
+/*
+ * 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/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/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
+
+/*
+ * Flags for txrx functions. More efficient that using an argument register for
+ * each one.
+ */
+#define TXRX_WRITE (1<<0) /* This is a write */
+#define TXRX_DEASSERT_CS (1<<1) /* De-assert CS at end of txrx */
+
+struct mxs_spi {
+ struct mxs_ssp ssp;
+ struct completion c;
+ unsigned int sck; /* Rate requested (vs actual) */
+};
+
+static int mxs_spi_setup_transfer(struct spi_device *dev,
+ const struct spi_transfer *t)
+{
+ struct mxs_spi *spi = spi_master_get_devdata(dev->master);
+ struct mxs_ssp *ssp = &spi->ssp;
+ const unsigned int hz = min(dev->max_speed_hz, t->speed_hz);
+
+ if (hz == 0) {
+ dev_err(&dev->dev, "SPI clock rate of zero not allowed\n");
+ return -EINVAL;
+ }
+
+ if (hz != spi->sck) {
+ mxs_ssp_set_clk_rate(ssp, hz);
+ /*
+ * Save requested rate, hz, rather than the actual rate,
+ * ssp->clk_rate. Otherwise we would set the rate every transfer
+ * when the actual rate is not quite the same as requested rate.
+ */
+ spi->sck = hz;
+ /*
+ * Perhaps we should return an error if the actual clock is
+ * nowhere close to what was requested?
+ */
+ }
+
+ writel(BM_SSP_CTRL0_LOCK_CS,
+ ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);
+
+ 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 u32 mxs_spi_cs_to_reg(unsigned cs)
+{
+ u32 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 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;
+ u32 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,
+ unsigned char *buf, int len,
+ unsigned int flags)
+{
+ 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;
+ u32 ctrl0;
+ struct page *vm_page;
+ struct {
+ u32 pio[4];
+ struct scatterlist sg;
+ } *dma_xfer;
+
+ if (!len)
+ return -EINVAL;
+
+ dma_xfer = kcalloc(sgs, sizeof(*dma_xfer), GFP_KERNEL);
+ if (!dma_xfer)
+ return -ENOMEM;
+
+ reinit_completion(&spi->c);
+
+ /* Chip select was already programmed into CTRL0 */
+ ctrl0 = readl(ssp->base + HW_SSP_CTRL0);
+ ctrl0 &= ~(BM_SSP_CTRL0_XFER_COUNT | BM_SSP_CTRL0_IGNORE_CRC |
+ BM_SSP_CTRL0_READ);
+ ctrl0 |= BM_SSP_CTRL0_DATA_XFER;
+
+ if (!(flags & TXRX_WRITE))
+ ctrl0 |= BM_SSP_CTRL0_READ;
+
+ /* Queue the DMA data transfer. */
+ for (sg_count = 0; sg_count < sgs; sg_count++) {
+ /* Prepare the transfer descriptor. */
+ min = min(len, desc_len);
+
+ /*
+ * De-assert CS on last segment if flag is set (i.e., no more
+ * transfers will follow)
+ */
+ if ((sg_count + 1 == sgs) && (flags & TXRX_DEASSERT_CS))
+ 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_init_table(&dma_xfer[sg_count].sg, 1);
+ sg_set_page(&dma_xfer[sg_count].sg, vm_page,
+ min, offset_in_page(buf));
+ } else {
+ sg_init_one(&dma_xfer[sg_count].sg, buf, min);
+ }
+
+ ret = dma_map_sg(ssp->dev, &dma_xfer[sg_count].sg, 1,
+ (flags & TXRX_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,
+ (flags & TXRX_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);
+
+ if (!wait_for_completion_timeout(&spi->c,
+ msecs_to_jiffies(SSP_TIMEOUT))) {
+ 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,
+ (flags & TXRX_WRITE) ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
+ }
+
+ kfree(dma_xfer);
+
+ return ret;
+}
+
+static int mxs_spi_txrx_pio(struct mxs_spi *spi,
+ unsigned char *buf, int len,
+ unsigned int flags)
+{
+ struct mxs_ssp *ssp = &spi->ssp;
+
+ writel(BM_SSP_CTRL0_IGNORE_CRC,
+ ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_CLR);
+
+ while (len--) {
+ if (len == 0 && (flags & TXRX_DEASSERT_CS))
+ writel(BM_SSP_CTRL0_IGNORE_CRC,
+ ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);
+
+ 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 (flags & TXRX_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 (flags & TXRX_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 (!(flags & TXRX_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;
+ struct spi_transfer *t;
+ unsigned int flag;
+ int status = 0;
+
+ /* Program CS register bits here, it will be used for all transfers. */
+ writel(BM_SSP_CTRL0_WAIT_FOR_CMD | BM_SSP_CTRL0_WAIT_FOR_IRQ,
+ ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_CLR);
+ writel(mxs_spi_cs_to_reg(m->spi->chip_select),
+ ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);
+
+ list_for_each_entry(t, &m->transfers, transfer_list) {
+
+ status = mxs_spi_setup_transfer(m->spi, t);
+ if (status)
+ break;
+
+ /* De-assert on last transfer, inverted by cs_change flag */
+ flag = (&t->transfer_list == m->transfers.prev) ^ t->cs_change ?
+ TXRX_DEASSERT_CS : 0;
+
+ /*
+ * 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,
+ (void *)t->tx_buf,
+ t->len, flag | TXRX_WRITE);
+ if (t->rx_buf)
+ status = mxs_spi_txrx_pio(spi,
+ t->rx_buf, t->len,
+ flag);
+ } 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,
+ (void *)t->tx_buf, t->len,
+ flag | TXRX_WRITE);
+ if (t->rx_buf)
+ status = mxs_spi_txrx_dma(spi,
+ t->rx_buf, t->len,
+ flag);
+ }
+
+ if (status) {
+ stmp_reset_block(ssp->base);
+ break;
+ }
+
+ m->actual_length += t->len;
+ }
+
+ 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 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 (irq_err < 0)
+ return irq_err;
+
+ base = devm_ioremap_resource(&pdev->dev, iores);
+ if (IS_ERR(base))
+ return PTR_ERR(base);
+
+ 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->bits_per_word_mask = SPI_BPW_MASK(8);
+ 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,
+ dev_name(&pdev->dev), 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;
+ }
+
+ ret = clk_prepare_enable(ssp->clk);
+ if (ret)
+ goto out_dma_release;
+
+ clk_set_rate(ssp->clk, clk_freq);
+
+ ret = stmp_reset_block(ssp->base);
+ if (ret)
+ goto out_disable_clk;
+
+ platform_set_drvdata(pdev, master);
+
+ ret = devm_spi_register_master(&pdev->dev, master);
+ if (ret) {
+ dev_err(&pdev->dev, "Cannot register SPI master, %d\n", ret);
+ goto out_disable_clk;
+ }
+
+ return 0;
+
+out_disable_clk:
+ clk_disable_unprepare(ssp->clk);
+out_dma_release:
+ dma_release_channel(ssp->dmach);
+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 = platform_get_drvdata(pdev);
+ spi = spi_master_get_devdata(master);
+ ssp = &spi->ssp;
+
+ clk_disable_unprepare(ssp->clk);
+ dma_release_channel(ssp->dmach);
+
+ return 0;
+}
+
+static struct platform_driver mxs_spi_driver = {
+ .probe = mxs_spi_probe,
+ .remove = mxs_spi_remove,
+ .driver = {
+ .name = DRIVER_NAME,
+ .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");
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-17 12:07:44 +0000