spi: spi-mem: add stm32 qspi controller

The qspi controller is a specialized communication interface
targeting single, dual or quad SPI Flash memories (NOR/NAND).

It can operate in any of the following modes:
-indirect mode: all the operations are performed using the quadspi
 registers
-read memory-mapped mode: the external Flash memory is mapped to the
 microcontroller address space and is seen by the system as if it was
 an internal memory

tested on:
-NOR: mx66l51235l
-NAND: MT29F2G01ABAGD

Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 512 insertions, 0 deletions

diff --git a/drivers/spi/spi-stm32-qspi.c b/drivers/spi/spi-stm32-qspi.c
new file mode 100644
index 000000000000..3b2a9a6b990d
--- /dev/null
+++ b/drivers/spi/spi-stm32-qspi.c
@@ -0,0 +1,512 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) STMicroelectronics 2018 - All Rights Reserved
+ * Author: Ludovic Barre <ludovic.barre@st.com> for STMicroelectronics.
+ */
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/errno.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+#include <linux/sizes.h>
+#include <linux/spi/spi-mem.h>
+
+#define QSPI_CR			0x00
+#define CR_EN			BIT(0)
+#define CR_ABORT		BIT(1)
+#define CR_DMAEN		BIT(2)
+#define CR_TCEN			BIT(3)
+#define CR_SSHIFT		BIT(4)
+#define CR_DFM			BIT(6)
+#define CR_FSEL			BIT(7)
+#define CR_FTHRES_MASK		GENMASK(12, 8)
+#define CR_TEIE			BIT(16)
+#define CR_TCIE			BIT(17)
+#define CR_FTIE			BIT(18)
+#define CR_SMIE			BIT(19)
+#define CR_TOIE			BIT(20)
+#define CR_PRESC_MASK		GENMASK(31, 24)
+
+#define QSPI_DCR		0x04
+#define DCR_FSIZE_MASK		GENMASK(20, 16)
+
+#define QSPI_SR			0x08
+#define SR_TEF			BIT(0)
+#define SR_TCF			BIT(1)
+#define SR_FTF			BIT(2)
+#define SR_SMF			BIT(3)
+#define SR_TOF			BIT(4)
+#define SR_BUSY			BIT(5)
+#define SR_FLEVEL_MASK		GENMASK(13, 8)
+
+#define QSPI_FCR		0x0c
+#define FCR_CTEF		BIT(0)
+#define FCR_CTCF		BIT(1)
+
+#define QSPI_DLR		0x10
+
+#define QSPI_CCR		0x14
+#define CCR_INST_MASK		GENMASK(7, 0)
+#define CCR_IMODE_MASK		GENMASK(9, 8)
+#define CCR_ADMODE_MASK		GENMASK(11, 10)
+#define CCR_ADSIZE_MASK		GENMASK(13, 12)
+#define CCR_DCYC_MASK		GENMASK(22, 18)
+#define CCR_DMODE_MASK		GENMASK(25, 24)
+#define CCR_FMODE_MASK		GENMASK(27, 26)
+#define CCR_FMODE_INDW		(0U << 26)
+#define CCR_FMODE_INDR		(1U << 26)
+#define CCR_FMODE_APM		(2U << 26)
+#define CCR_FMODE_MM		(3U << 26)
+#define CCR_BUSWIDTH_0		0x0
+#define CCR_BUSWIDTH_1		0x1
+#define CCR_BUSWIDTH_2		0x2
+#define CCR_BUSWIDTH_4		0x3
+
+#define QSPI_AR			0x18
+#define QSPI_ABR		0x1c
+#define QSPI_DR			0x20
+#define QSPI_PSMKR		0x24
+#define QSPI_PSMAR		0x28
+#define QSPI_PIR		0x2c
+#define QSPI_LPTR		0x30
+#define LPTR_DFT_TIMEOUT	0x10
+
+#define STM32_QSPI_MAX_MMAP_SZ	SZ_256M
+#define STM32_QSPI_MAX_NORCHIP	2
+
+#define STM32_FIFO_TIMEOUT_US 30000
+#define STM32_BUSY_TIMEOUT_US 100000
+#define STM32_ABT_TIMEOUT_US 100000
+
+struct stm32_qspi_flash {
+	struct stm32_qspi *qspi;
+	u32 cs;
+	u32 presc;
+};
+
+struct stm32_qspi {
+	struct device *dev;
+	void __iomem *io_base;
+	void __iomem *mm_base;
+	resource_size_t mm_size;
+	struct clk *clk;
+	u32 clk_rate;
+	struct stm32_qspi_flash flash[STM32_QSPI_MAX_NORCHIP];
+	struct completion data_completion;
+	u32 fmode;
+
+	/*
+	 * to protect device configuration, could be different between
+	 * 2 flash access (bk1, bk2)
+	 */
+	struct mutex lock;
+};
+
+static irqreturn_t stm32_qspi_irq(int irq, void *dev_id)
+{
+	struct stm32_qspi *qspi = (struct stm32_qspi *)dev_id;
+	u32 cr, sr;
+
+	sr = readl_relaxed(qspi->io_base + QSPI_SR);
+
+	if (sr & (SR_TEF | SR_TCF)) {
+		/* disable irq */
+		cr = readl_relaxed(qspi->io_base + QSPI_CR);
+		cr &= ~CR_TCIE & ~CR_TEIE;
+		writel_relaxed(cr, qspi->io_base + QSPI_CR);
+		complete(&qspi->data_completion);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static void stm32_qspi_read_fifo(u8 *val, void __iomem *addr)
+{
+	*val = readb_relaxed(addr);
+}
+
+static void stm32_qspi_write_fifo(u8 *val, void __iomem *addr)
+{
+	writeb_relaxed(*val, addr);
+}
+
+static int stm32_qspi_tx_poll(struct stm32_qspi *qspi,
+			      const struct spi_mem_op *op)
+{
+	void (*tx_fifo)(u8 *val, void __iomem *addr);
+	u32 len = op->data.nbytes, sr;
+	u8 *buf;
+	int ret;
+
+	if (op->data.dir == SPI_MEM_DATA_IN) {
+		tx_fifo = stm32_qspi_read_fifo;
+		buf = op->data.buf.in;
+
+	} else {
+		tx_fifo = stm32_qspi_write_fifo;
+		buf = (u8 *)op->data.buf.out;
+	}
+
+	while (len--) {
+		ret = readl_relaxed_poll_timeout_atomic(qspi->io_base + QSPI_SR,
+							sr, (sr & SR_FTF), 1,
+							STM32_FIFO_TIMEOUT_US);
+		if (ret) {
+			dev_err(qspi->dev, "fifo timeout (len:%d stat:%#x)\n",
+				len, sr);
+			return ret;
+		}
+		tx_fifo(buf++, qspi->io_base + QSPI_DR);
+	}
+
+	return 0;
+}
+
+static int stm32_qspi_tx_mm(struct stm32_qspi *qspi,
+			    const struct spi_mem_op *op)
+{
+	memcpy_fromio(op->data.buf.in, qspi->mm_base + op->addr.val,
+		      op->data.nbytes);
+	return 0;
+}
+
+static int stm32_qspi_tx(struct stm32_qspi *qspi, const struct spi_mem_op *op)
+{
+	if (!op->data.nbytes)
+		return 0;
+
+	if (qspi->fmode == CCR_FMODE_MM)
+		return stm32_qspi_tx_mm(qspi, op);
+
+	return stm32_qspi_tx_poll(qspi, op);
+}
+
+static int stm32_qspi_wait_nobusy(struct stm32_qspi *qspi)
+{
+	u32 sr;
+
+	return readl_relaxed_poll_timeout_atomic(qspi->io_base + QSPI_SR, sr,
+						 !(sr & SR_BUSY), 1,
+						 STM32_BUSY_TIMEOUT_US);
+}
+
+static int stm32_qspi_wait_cmd(struct stm32_qspi *qspi,
+			       const struct spi_mem_op *op)
+{
+	u32 cr, sr;
+	int err = 0;
+
+	if (!op->data.nbytes)
+		return stm32_qspi_wait_nobusy(qspi);
+
+	if (readl_relaxed(qspi->io_base + QSPI_SR) & SR_TCF)
+		goto out;
+
+	reinit_completion(&qspi->data_completion);
+	cr = readl_relaxed(qspi->io_base + QSPI_CR);
+	writel_relaxed(cr | CR_TCIE | CR_TEIE, qspi->io_base + QSPI_CR);
+
+	if (!wait_for_completion_interruptible_timeout(&qspi->data_completion,
+						msecs_to_jiffies(1000))) {
+		err = -ETIMEDOUT;
+	} else {
+		sr = readl_relaxed(qspi->io_base + QSPI_SR);
+		if (sr & SR_TEF)
+			err = -EIO;
+	}
+
+out:
+	/* clear flags */
+	writel_relaxed(FCR_CTCF | FCR_CTEF, qspi->io_base + QSPI_FCR);
+
+	return err;
+}
+
+static int stm32_qspi_get_mode(struct stm32_qspi *qspi, u8 buswidth)
+{
+	if (buswidth == 4)
+		return CCR_BUSWIDTH_4;
+
+	return buswidth;
+}
+
+static int stm32_qspi_send(struct spi_mem *mem, const struct spi_mem_op *op)
+{
+	struct stm32_qspi *qspi = spi_controller_get_devdata(mem->spi->master);
+	struct stm32_qspi_flash *flash = &qspi->flash[mem->spi->chip_select];
+	u32 ccr, cr, addr_max;
+	int timeout, err = 0;
+
+	dev_dbg(qspi->dev, "cmd:%#x mode:%d.%d.%d.%d addr:%#llx len:%#x\n",
+		op->cmd.opcode, op->cmd.buswidth, op->addr.buswidth,
+		op->dummy.buswidth, op->data.buswidth,
+		op->addr.val, op->data.nbytes);
+
+	err = stm32_qspi_wait_nobusy(qspi);
+	if (err)
+		goto abort;
+
+	addr_max = op->addr.val + op->data.nbytes + 1;
+
+	if (op->data.dir == SPI_MEM_DATA_IN) {
+		if (addr_max < qspi->mm_size &&
+		    op->addr.buswidth)
+			qspi->fmode = CCR_FMODE_MM;
+		else
+			qspi->fmode = CCR_FMODE_INDR;
+	} else {
+		qspi->fmode = CCR_FMODE_INDW;
+	}
+
+	cr = readl_relaxed(qspi->io_base + QSPI_CR);
+	cr &= ~CR_PRESC_MASK & ~CR_FSEL;
+	cr |= FIELD_PREP(CR_PRESC_MASK, flash->presc);
+	cr |= FIELD_PREP(CR_FSEL, flash->cs);
+	writel_relaxed(cr, qspi->io_base + QSPI_CR);
+
+	if (op->data.nbytes)
+		writel_relaxed(op->data.nbytes - 1,
+			       qspi->io_base + QSPI_DLR);
+	else
+		qspi->fmode = CCR_FMODE_INDW;
+
+	ccr = qspi->fmode;
+	ccr |= FIELD_PREP(CCR_INST_MASK, op->cmd.opcode);
+	ccr |= FIELD_PREP(CCR_IMODE_MASK,
+			  stm32_qspi_get_mode(qspi, op->cmd.buswidth));
+
+	if (op->addr.nbytes) {
+		ccr |= FIELD_PREP(CCR_ADMODE_MASK,
+				  stm32_qspi_get_mode(qspi, op->addr.buswidth));
+		ccr |= FIELD_PREP(CCR_ADSIZE_MASK, op->addr.nbytes - 1);
+	}
+
+	if (op->dummy.buswidth && op->dummy.nbytes)
+		ccr |= FIELD_PREP(CCR_DCYC_MASK,
+				  op->dummy.nbytes * 8 / op->dummy.buswidth);
+
+	if (op->data.nbytes) {
+		ccr |= FIELD_PREP(CCR_DMODE_MASK,
+				  stm32_qspi_get_mode(qspi, op->data.buswidth));
+	}
+
+	writel_relaxed(ccr, qspi->io_base + QSPI_CCR);
+
+	if (op->addr.nbytes && qspi->fmode != CCR_FMODE_MM)
+		writel_relaxed(op->addr.val, qspi->io_base + QSPI_AR);
+
+	err = stm32_qspi_tx(qspi, op);
+
+	/*
+	 * Abort in:
+	 * -error case
+	 * -read memory map: prefetching must be stopped if we read the last
+	 *  byte of device (device size - fifo size). like device size is not
+	 *  knows, the prefetching is always stop.
+	 */
+	if (err || qspi->fmode == CCR_FMODE_MM)
+		goto abort;
+
+	/* wait end of tx in indirect mode */
+	err = stm32_qspi_wait_cmd(qspi, op);
+	if (err)
+		goto abort;
+
+	return 0;
+
+abort:
+	cr = readl_relaxed(qspi->io_base + QSPI_CR) | CR_ABORT;
+	writel_relaxed(cr, qspi->io_base + QSPI_CR);
+
+	/* wait clear of abort bit by hw */
+	timeout = readl_relaxed_poll_timeout_atomic(qspi->io_base + QSPI_CR,
+						    cr, !(cr & CR_ABORT), 1,
+						    STM32_ABT_TIMEOUT_US);
+
+	writel_relaxed(FCR_CTCF, qspi->io_base + QSPI_FCR);
+
+	if (err || timeout)
+		dev_err(qspi->dev, "%s err:%d abort timeout:%d\n",
+			__func__, err, timeout);
+
+	return err;
+}
+
+static int stm32_qspi_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
+{
+	struct stm32_qspi *qspi = spi_controller_get_devdata(mem->spi->master);
+	int ret;
+
+	mutex_lock(&qspi->lock);
+	ret = stm32_qspi_send(mem, op);
+	mutex_unlock(&qspi->lock);
+
+	return ret;
+}
+
+static int stm32_qspi_setup(struct spi_device *spi)
+{
+	struct spi_controller *ctrl = spi->master;
+	struct stm32_qspi *qspi = spi_controller_get_devdata(ctrl);
+	struct stm32_qspi_flash *flash;
+	u32 cr, presc;
+
+	if (ctrl->busy)
+		return -EBUSY;
+
+	if (!spi->max_speed_hz)
+		return -EINVAL;
+
+	presc = DIV_ROUND_UP(qspi->clk_rate, spi->max_speed_hz) - 1;
+
+	flash = &qspi->flash[spi->chip_select];
+	flash->qspi = qspi;
+	flash->cs = spi->chip_select;
+	flash->presc = presc;
+
+	mutex_lock(&qspi->lock);
+	writel_relaxed(LPTR_DFT_TIMEOUT, qspi->io_base + QSPI_LPTR);
+	cr = FIELD_PREP(CR_FTHRES_MASK, 3) | CR_TCEN | CR_SSHIFT | CR_EN;
+	writel_relaxed(cr, qspi->io_base + QSPI_CR);
+
+	/* set dcr fsize to max address */
+	writel_relaxed(DCR_FSIZE_MASK, qspi->io_base + QSPI_DCR);
+	mutex_unlock(&qspi->lock);
+
+	return 0;
+}
+
+/*
+ * no special host constraint, so use default spi_mem_default_supports_op
+ * to check supported mode.
+ */
+static const struct spi_controller_mem_ops stm32_qspi_mem_ops = {
+	.exec_op = stm32_qspi_exec_op,
+};
+
+static void stm32_qspi_release(struct stm32_qspi *qspi)
+{
+	/* disable qspi */
+	writel_relaxed(0, qspi->io_base + QSPI_CR);
+	mutex_destroy(&qspi->lock);
+	clk_disable_unprepare(qspi->clk);
+}
+
+static int stm32_qspi_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct spi_controller *ctrl;
+	struct reset_control *rstc;
+	struct stm32_qspi *qspi;
+	struct resource *res;
+	int ret, irq;
+
+	ctrl = spi_alloc_master(dev, sizeof(*qspi));
+	if (!ctrl)
+		return -ENOMEM;
+
+	qspi = spi_controller_get_devdata(ctrl);
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "qspi");
+	qspi->io_base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(qspi->io_base))
+		return PTR_ERR(qspi->io_base);
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "qspi_mm");
+	qspi->mm_base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(qspi->mm_base))
+		return PTR_ERR(qspi->mm_base);
+
+	qspi->mm_size = resource_size(res);
+	if (qspi->mm_size > STM32_QSPI_MAX_MMAP_SZ)
+		return -EINVAL;
+
+	irq = platform_get_irq(pdev, 0);
+	ret = devm_request_irq(dev, irq, stm32_qspi_irq, 0,
+			       dev_name(dev), qspi);
+	if (ret) {
+		dev_err(dev, "failed to request irq\n");
+		return ret;
+	}
+
+	init_completion(&qspi->data_completion);
+
+	qspi->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(qspi->clk))
+		return PTR_ERR(qspi->clk);
+
+	qspi->clk_rate = clk_get_rate(qspi->clk);
+	if (!qspi->clk_rate)
+		return -EINVAL;
+
+	ret = clk_prepare_enable(qspi->clk);
+	if (ret) {
+		dev_err(dev, "can not enable the clock\n");
+		return ret;
+	}
+
+	rstc = devm_reset_control_get_exclusive(dev, NULL);
+	if (!IS_ERR(rstc)) {
+		reset_control_assert(rstc);
+		udelay(2);
+		reset_control_deassert(rstc);
+	}
+
+	qspi->dev = dev;
+	platform_set_drvdata(pdev, qspi);
+	mutex_init(&qspi->lock);
+
+	ctrl->mode_bits = SPI_RX_DUAL | SPI_RX_QUAD
+		| SPI_TX_DUAL | SPI_TX_QUAD;
+	ctrl->setup = stm32_qspi_setup;
+	ctrl->bus_num = -1;
+	ctrl->mem_ops = &stm32_qspi_mem_ops;
+	ctrl->num_chipselect = STM32_QSPI_MAX_NORCHIP;
+	ctrl->dev.of_node = dev->of_node;
+
+	ret = devm_spi_register_master(dev, ctrl);
+	if (ret)
+		goto err_spi_register;
+
+	return 0;
+
+err_spi_register:
+	stm32_qspi_release(qspi);
+
+	return ret;
+}
+
+static int stm32_qspi_remove(struct platform_device *pdev)
+{
+	struct stm32_qspi *qspi = platform_get_drvdata(pdev);
+
+	stm32_qspi_release(qspi);
+	return 0;
+}
+
+static const struct of_device_id stm32_qspi_match[] = {
+	{.compatible = "st,stm32f469-qspi"},
+	{}
+};
+MODULE_DEVICE_TABLE(of, stm32_qspi_match);
+
+static struct platform_driver stm32_qspi_driver = {
+	.probe	= stm32_qspi_probe,
+	.remove	= stm32_qspi_remove,
+	.driver	= {
+		.name = "stm32-qspi",
+		.of_match_table = stm32_qspi_match,
+	},
+};
+module_platform_driver(stm32_qspi_driver);
+
+MODULE_AUTHOR("Ludovic Barre <ludovic.barre@st.com>");
+MODULE_DESCRIPTION("STMicroelectronics STM32 quad spi driver");
+MODULE_LICENSE("GPL v2");