[PATCH v2 03/12] spi: Add a driver for the Freescale/NXP QuadSPI controller

[frieder.schrempf@xxxxxxxxx (Frieder Schrempf)]

This driver is derived from the SPI NOR driver at
mtd/spi-nor/fsl-quadspi.c. It uses the new SPI memory interface
of the SPI framework to issue flash memory operations to up to
four connected flash chips (2 buses with 2 CS each).

The controller does not support generic SPI messages.

Signed-off-by: Frieder Schrempf <frieder.schrempf at exceet.de>
---
Changes in v2:
==============
* Add Yogesh Gaur and Suresh Gupta as authors
* Use GENMASK() for generating bitmasks
* Use callback functions for read/write of registers
* Attach the seq variable to the selected CS
* Avoid using conditional in read/write loop
* Avoid infinite loop and use a timeout instead
* Return error pointer when allocation in fsl_qspi_get_name() fails
* Remove redundant iounmap()
* Put suspend()/resume() in struct dev_pm_ops instead of struct platform_driver

 drivers/spi/Kconfig        |  11 +
 drivers/spi/Makefile       |   1 +
 drivers/spi/spi-fsl-qspi.c | 954 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 966 insertions(+)

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index ad5d68e..5e95ffc 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -251,6 +251,17 @@ config SPI_FSL_LPSPI
 	help
 	  This enables Freescale i.MX LPSPI controllers in master mode.
 
+config SPI_FSL_QSPI
+	tristate "Freescale QSPI controller"
+	depends on ARCH_MXC || SOC_LS1021A || ARCH_LAYERSCAPE || COMPILE_TEST
+	depends on HAS_IOMEM
+	help
+	  This enables support for the Quad SPI controller in master mode.
+	  Up to four flash chips can be connected on two buses with two
+	  chipselects each.
+	  This controller does not support generic SPI messages. It only
+	  supports the high-level SPI memory interface.
+
 config SPI_GPIO
 	tristate "GPIO-based bitbanging SPI Master"
 	depends on GPIOLIB || COMPILE_TEST
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index cb1f437..a8f7fda 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -43,6 +43,7 @@ obj-$(CONFIG_SPI_FSL_DSPI)		+= spi-fsl-dspi.o
 obj-$(CONFIG_SPI_FSL_LIB)		+= spi-fsl-lib.o
 obj-$(CONFIG_SPI_FSL_ESPI)		+= spi-fsl-espi.o
 obj-$(CONFIG_SPI_FSL_LPSPI)		+= spi-fsl-lpspi.o
+obj-$(CONFIG_SPI_FSL_QSPI)		+= spi-fsl-qspi.o
 obj-$(CONFIG_SPI_FSL_SPI)		+= spi-fsl-spi.o
 obj-$(CONFIG_SPI_GPIO)			+= spi-gpio.o
 obj-$(CONFIG_SPI_IMG_SPFI)		+= spi-img-spfi.o
diff --git a/drivers/spi/spi-fsl-qspi.c b/drivers/spi/spi-fsl-qspi.c
new file mode 100644
index 0000000..3e17209
--- /dev/null
+++ b/drivers/spi/spi-fsl-qspi.c
@@ -0,0 +1,954 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+/*
+ * Freescale QuadSPI driver.
+ *
+ * Copyright (C) 2013 Freescale Semiconductor, Inc.
+ * Copyright (C) 2018 Bootlin
+ * Copyright (C) 2018 Exceet Electronics GmbH
+ *
+ * Transition to SPI MEM interface:
+ * Author:
+ *     Boris Brezillion <boris.brezillon at bootlin.com>
+ *     Frieder Schrempf <frieder.schrempf at exceet.de>
+ *     Yogesh Gaur <yogeshnarayan.gaur at nxp.com>
+ *     Suresh Gupta <suresh.gupta at nxp.com>
+ *
+ * Based on the original fsl-quadspi.c spi-nor driver:
+ * Author: Freescale Semiconductor, Inc.
+ *
+ */
+
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/jiffies.h>
+#include <linux/kernel.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/pm_qos.h>
+#include <linux/sizes.h>
+
+#include <linux/spi/spi.h>
+#include <linux/spi/spi-mem.h>
+
+/*
+ * The driver only uses one single LUT entry, that is updated on
+ * each call of exec_op(). Index 0 is preset at boot with a basic
+ * read operation, so let's use the last entry (15).
+ */
+#define	SEQID_LUT			15
+
+/* Registers used by the driver */
+#define QUADSPI_MCR			0x00
+#define QUADSPI_MCR_RESERVED_MASK	GENMASK(19, 16)
+#define QUADSPI_MCR_MDIS_MASK		BIT(14)
+#define QUADSPI_MCR_CLR_TXF_MASK	BIT(11)
+#define QUADSPI_MCR_CLR_RXF_MASK	BIT(10)
+#define QUADSPI_MCR_DDR_EN_MASK		BIT(7)
+#define QUADSPI_MCR_END_CFG_MASK	GENMASK(3, 2)
+#define QUADSPI_MCR_SWRSTHD_MASK	BIT(1)
+#define QUADSPI_MCR_SWRSTSD_MASK	BIT(0)
+
+#define QUADSPI_IPCR			0x08
+#define QUADSPI_IPCR_SEQID_SHIFT	24
+
+#define QUADSPI_BUF3CR			0x1c
+#define QUADSPI_BUF3CR_ALLMST_MASK	BIT(31)
+#define QUADSPI_BUF3CR_ADATSZ_SHIFT	8
+#define QUADSPI_BUF3CR_ADATSZ_MASK	(0xFF << QUADSPI_BUF3CR_ADATSZ_SHIFT)
+
+#define QUADSPI_BFGENCR			0x20
+#define QUADSPI_BFGENCR_SEQID_SHIFT	12
+
+#define QUADSPI_BUF0IND			0x30
+#define QUADSPI_BUF1IND			0x34
+#define QUADSPI_BUF2IND			0x38
+#define QUADSPI_SFAR			0x100
+
+#define QUADSPI_SMPR			0x108
+#define QUADSPI_SMPR_DDRSMP_MASK	GENMASK(18, 16)
+#define QUADSPI_SMPR_FSDLY_MASK		BIT(6)
+#define QUADSPI_SMPR_FSPHS_MASK		BIT(5)
+#define QUADSPI_SMPR_HSENA_MASK		BIT(0)
+
+#define QUADSPI_RBCT			0x110
+#define QUADSPI_RBCT_WMRK_MASK		GENMASK(4, 0)
+#define QUADSPI_RBCT_RXBRD_USEIPS	BIT(8)
+
+#define QUADSPI_TBDR			0x154
+
+#define QUADSPI_SR			0x15c
+#define QUADSPI_SR_IP_ACC_MASK		BIT(1)
+#define QUADSPI_SR_AHB_ACC_MASK		BIT(2)
+
+#define QUADSPI_FR			0x160
+#define QUADSPI_FR_TFF_MASK		BIT(0)
+
+#define QUADSPI_SPTRCLR			0x16c
+#define QUADSPI_SPTRCLR_IPPTRC		BIT(8)
+#define QUADSPI_SPTRCLR_BFPTRC		BIT(0)
+
+#define QUADSPI_SFA1AD			0x180
+#define QUADSPI_SFA2AD			0x184
+#define QUADSPI_SFB1AD			0x188
+#define QUADSPI_SFB2AD			0x18c
+#define QUADSPI_RBDR(x)			(0x200 + ((x) * 4))
+
+#define QUADSPI_LUTKEY			0x300
+#define QUADSPI_LUTKEY_VALUE		0x5AF05AF0
+
+#define QUADSPI_LCKCR			0x304
+#define QUADSPI_LCKER_LOCK		BIT(0)
+#define QUADSPI_LCKER_UNLOCK		BIT(1)
+
+#define QUADSPI_RSER			0x164
+#define QUADSPI_RSER_TFIE		BIT(0)
+
+#define QUADSPI_LUT_BASE		0x310
+#define QUADSPI_LUT_OFFSET		(SEQID_LUT * 4 * 4)
+#define QUADSPI_LUT_REG(idx) \
+	(QUADSPI_LUT_BASE + QUADSPI_LUT_OFFSET + (idx) * 4)
+
+/* Instruction set for the LUT register */
+#define LUT_STOP		0
+#define LUT_CMD			1
+#define LUT_ADDR		2
+#define LUT_DUMMY		3
+#define LUT_MODE		4
+#define LUT_MODE2		5
+#define LUT_MODE4		6
+#define LUT_FSL_READ		7
+#define LUT_FSL_WRITE		8
+#define LUT_JMP_ON_CS		9
+#define LUT_ADDR_DDR		10
+#define LUT_MODE_DDR		11
+#define LUT_MODE2_DDR		12
+#define LUT_MODE4_DDR		13
+#define LUT_FSL_READ_DDR	14
+#define LUT_FSL_WRITE_DDR	15
+#define LUT_DATA_LEARN		16
+
+/*
+ * The PAD definitions for LUT register.
+ *
+ * The pad stands for the number of IO lines [0:3].
+ * For example, the quad read needs four IO lines,
+ * so you should use LUT_PAD(4).
+ */
+#define LUT_PAD(x) (fls(x) - 1)
+
+/*
+ * Macro for constructing the LUT entries with the following
+ * register layout:
+ *
+ *  ---------------------------------------------------
+ *  | INSTR1 | PAD1 | OPRND1 | INSTR0 | PAD0 | OPRND0 |
+ *  ---------------------------------------------------
+ */
+#define LUT_DEF(idx, ins, pad, opr)					\
+	((((ins) << 10) | ((pad) << 8) | (opr)) << (((idx) % 2) * 16))
+
+/* Controller needs driver to swap endianness */
+#define QUADSPI_QUIRK_SWAP_ENDIAN	BIT(0)
+
+/* Controller needs 4x internal clock */
+#define QUADSPI_QUIRK_4X_INT_CLK	BIT(1)
+
+/*
+ * TKT253890, the controller needs the driver to fill the txfifo with
+ * 16 bytes at least to trigger a data transfer, even though the extra
+ * data won't be transferred.
+ */
+#define QUADSPI_QUIRK_TKT253890		BIT(2)
+
+/* TKT245618, the controller cannot wake up from wait mode */
+#define QUADSPI_QUIRK_TKT245618		BIT(3)
+
+enum fsl_qspi_devtype {
+	FSL_QUADSPI_VYBRID,
+	FSL_QUADSPI_IMX6SX,
+	FSL_QUADSPI_IMX7D,
+	FSL_QUADSPI_IMX6UL,
+	FSL_QUADSPI_LS1021A,
+	FSL_QUADSPI_LS2080A,
+};
+
+struct fsl_qspi_devtype_data {
+	enum fsl_qspi_devtype devtype;
+	unsigned int rxfifo;
+	unsigned int txfifo;
+	unsigned int ahb_buf_size;
+	unsigned int quirks;
+};
+
+static const struct fsl_qspi_devtype_data vybrid_data = {
+	.devtype = FSL_QUADSPI_VYBRID,
+	.rxfifo = SZ_128,
+	.txfifo = SZ_64,
+	.ahb_buf_size = SZ_1K,
+	.quirks = QUADSPI_QUIRK_SWAP_ENDIAN,
+};
+
+static const struct fsl_qspi_devtype_data imx6sx_data = {
+	.devtype = FSL_QUADSPI_IMX6SX,
+	.rxfifo = SZ_128,
+	.txfifo = SZ_512,
+	.ahb_buf_size = SZ_1K,
+	.quirks = QUADSPI_QUIRK_4X_INT_CLK | QUADSPI_QUIRK_TKT245618,
+};
+
+static const struct fsl_qspi_devtype_data imx7d_data = {
+	.devtype = FSL_QUADSPI_IMX7D,
+	.rxfifo = SZ_512,
+	.txfifo = SZ_512,
+	.ahb_buf_size = SZ_1K,
+	.quirks = QUADSPI_QUIRK_TKT253890 | QUADSPI_QUIRK_4X_INT_CLK,
+};
+
+static const struct fsl_qspi_devtype_data imx6ul_data = {
+	.devtype = FSL_QUADSPI_IMX6UL,
+	.rxfifo = SZ_128,
+	.txfifo = SZ_512,
+	.ahb_buf_size = SZ_1K,
+	.quirks = QUADSPI_QUIRK_TKT253890 | QUADSPI_QUIRK_4X_INT_CLK,
+};
+
+static const struct fsl_qspi_devtype_data ls1021a_data = {
+	.devtype = FSL_QUADSPI_LS1021A,
+	.rxfifo = SZ_128,
+	.txfifo = SZ_64,
+	.ahb_buf_size = SZ_1K,
+	.quirks = 0,
+};
+
+static const struct fsl_qspi_devtype_data ls2080a_data = {
+	.devtype = FSL_QUADSPI_LS2080A,
+	.rxfifo = SZ_128,
+	.txfifo = SZ_64,
+	.ahb_buf_size = SZ_1K,
+	.quirks = QUADSPI_QUIRK_TKT253890,
+};
+
+struct fsl_qspi {
+	void __iomem *iobase;
+	void __iomem *ahb_addr;
+	u32 memmap_phy;
+	struct clk *clk, *clk_en;
+	struct device *dev;
+	struct completion c;
+	const struct fsl_qspi_devtype_data *devtype_data;
+	bool big_endian;
+	struct mutex lock;
+	struct pm_qos_request pm_qos_req;
+	int selected;
+	u8 seq;
+	void (*write)(u32 val, void __iomem *addr);
+	u32 (*read)(void __iomem *addr);
+};
+
+static inline int needs_swap_endian(struct fsl_qspi *q)
+{
+	return q->devtype_data->quirks & QUADSPI_QUIRK_SWAP_ENDIAN;
+}
+
+static inline int needs_4x_clock(struct fsl_qspi *q)
+{
+	return q->devtype_data->quirks & QUADSPI_QUIRK_4X_INT_CLK;
+}
+
+static inline int needs_fill_txfifo(struct fsl_qspi *q)
+{
+	return q->devtype_data->quirks & QUADSPI_QUIRK_TKT253890;
+}
+
+static inline int needs_wakeup_wait_mode(struct fsl_qspi *q)
+{
+	return q->devtype_data->quirks & QUADSPI_QUIRK_TKT245618;
+}
+
+/*
+ * An IC bug makes it necessary to rearrange the 32-bit data.
+ * Later chips, such as IMX6SLX, have fixed this bug.
+ */
+static inline u32 fsl_qspi_endian_xchg(struct fsl_qspi *q, u32 a)
+{
+	return needs_swap_endian(q) ? __swab32(a) : a;
+}
+
+static void qspi_writel_be(u32 val, void __iomem *addr)
+{
+	iowrite32be(val, addr);
+}
+
+static void qspi_writel(u32 val, void __iomem *addr)
+{
+	iowrite32(val, addr);
+}
+
+static u32 qspi_readl_be(void __iomem *addr)
+{
+	return ioread32be(addr);
+}
+
+static u32 qspi_readl(void __iomem *addr)
+{
+	return ioread32(addr);
+}
+
+static irqreturn_t fsl_qspi_irq_handler(int irq, void *dev_id)
+{
+	struct fsl_qspi *q = dev_id;
+	u32 reg;
+
+	/* clear interrupt */
+	reg = q->read(q->iobase + QUADSPI_FR);
+	q->write(reg, q->iobase + QUADSPI_FR);
+
+	if (reg & QUADSPI_FR_TFF_MASK)
+		complete(&q->c);
+
+	dev_dbg(q->dev, "QUADSPI_FR : 0x%.8x:0x%.8x\n", 0, reg);
+	return IRQ_HANDLED;
+}
+
+static int fsl_qspi_check_buswidth(struct fsl_qspi *q, u8 width)
+{
+	switch (width) {
+	case 1:
+	case 2:
+	case 4:
+		return 0;
+	}
+
+	return -ENOTSUPP;
+}
+
+static bool fsl_qspi_supports_op(struct spi_mem *mem,
+				 const struct spi_mem_op *op)
+{
+	struct fsl_qspi *q = spi_controller_get_devdata(mem->spi->master);
+	int ret;
+
+	ret = fsl_qspi_check_buswidth(q, op->cmd.buswidth);
+
+	if (op->addr.nbytes)
+		ret |= fsl_qspi_check_buswidth(q, op->addr.buswidth);
+
+	if (op->dummy.nbytes)
+		ret |= fsl_qspi_check_buswidth(q, op->dummy.buswidth);
+
+	if (op->data.nbytes)
+		ret |= fsl_qspi_check_buswidth(q, op->data.buswidth);
+
+	if (ret)
+		return false;
+
+	/*
+	 * The number of instructions needed for the op, needs
+	 * to fit into a single LUT entry.
+	 */
+	if (op->addr.nbytes +
+	   (op->dummy.nbytes ? 1:0) +
+	   (op->data.nbytes ? 1:0) > 6)
+		return false;
+
+	/* Max 64 dummy clock cycles supported */
+	if (op->dummy.nbytes * 8 / op->dummy.buswidth > 64)
+		return false;
+
+	/* Max data length, check controller limits and alignment */
+	if (op->data.dir == SPI_MEM_DATA_IN &&
+	    (op->data.nbytes > q->devtype_data->ahb_buf_size ||
+	     (op->data.nbytes > q->devtype_data->rxfifo - 4 &&
+	      !IS_ALIGNED(op->data.nbytes, 8))))
+		return false;
+
+	if (op->data.dir == SPI_MEM_DATA_OUT &&
+	    op->data.nbytes > q->devtype_data->txfifo)
+		return false;
+
+	return true;
+}
+
+static void fsl_qspi_prepare_lut(struct fsl_qspi *q,
+				 const struct spi_mem_op *op)
+{
+	void __iomem *base = q->iobase;
+	u32 lutval[4] = {};
+	int lutidx = 1, i;
+
+	lutval[0] |= LUT_DEF(0, LUT_CMD, LUT_PAD(op->cmd.buswidth),
+			     op->cmd.opcode);
+
+	/*
+	 * For some unknown reason, using LUT_ADDR doesn't work in some
+	 * cases (at least with only one byte long addresses), so
+	 * let's use LUT_MODE to write the address bytes one by one
+	 */
+	for (i = 0; i < op->addr.nbytes; i++) {
+		u8 addrbyte = op->addr.val >> (8 * (op->addr.nbytes - i - 1));
+
+		lutval[lutidx / 2] |= LUT_DEF(lutidx, LUT_MODE,
+					      LUT_PAD(op->addr.buswidth),
+					      addrbyte);
+		lutidx++;
+	}
+
+	if (op->dummy.nbytes) {
+		lutval[lutidx / 2] |= LUT_DEF(lutidx, LUT_DUMMY,
+					      LUT_PAD(op->dummy.buswidth),
+					      op->dummy.nbytes * 8 /
+					      op->dummy.buswidth);
+		lutidx++;
+	}
+
+	if (op->data.nbytes) {
+		lutval[lutidx / 2] |= LUT_DEF(lutidx,
+					      op->data.dir == SPI_MEM_DATA_IN ?
+					      LUT_FSL_READ : LUT_FSL_WRITE,
+					      LUT_PAD(op->data.buswidth),
+					      0);
+		lutidx++;
+	}
+
+	lutval[lutidx / 2] |= LUT_DEF(lutidx, LUT_STOP, 0, 0);
+
+	/* unlock LUT */
+	q->write(QUADSPI_LUTKEY_VALUE, q->iobase + QUADSPI_LUTKEY);
+	q->write(QUADSPI_LCKER_UNLOCK, q->iobase + QUADSPI_LCKCR);
+
+	/* fill LUT */
+	for (i = 0; i < ARRAY_SIZE(lutval); i++)
+		q->write(lutval[i], base + QUADSPI_LUT_REG(i));
+
+	/* lock LUT */
+	q->write(QUADSPI_LUTKEY_VALUE, q->iobase + QUADSPI_LUTKEY);
+	q->write(QUADSPI_LCKER_LOCK, q->iobase + QUADSPI_LCKCR);
+}
+
+static int fsl_qspi_clk_prep_enable(struct fsl_qspi *q)
+{
+	int ret;
+
+	ret = clk_prepare_enable(q->clk_en);
+	if (ret)
+		return ret;
+
+	ret = clk_prepare_enable(q->clk);
+	if (ret) {
+		clk_disable_unprepare(q->clk_en);
+		return ret;
+	}
+
+	if (needs_wakeup_wait_mode(q))
+		pm_qos_add_request(&q->pm_qos_req, PM_QOS_CPU_DMA_LATENCY, 0);
+
+	return 0;
+}
+
+static void fsl_qspi_clk_disable_unprep(struct fsl_qspi *q)
+{
+	if (needs_wakeup_wait_mode(q))
+		pm_qos_remove_request(&q->pm_qos_req);
+
+	clk_disable_unprepare(q->clk);
+	clk_disable_unprepare(q->clk_en);
+}
+
+static void fsl_qspi_select_mem(struct fsl_qspi *q, struct spi_device *spi)
+{
+	unsigned long rate = spi->max_speed_hz;
+	int ret, i;
+	u32 map_addr;
+
+	if (q->selected == spi->chip_select)
+		return;
+
+	/*
+	 * In HW there can be a maximum of four chips on two buses with
+	 * two chip selects on each bus. We use four chip selects in SW
+	 * to differentiate between the four chips.
+	 * We use the SFA1AD, SFA2AD, SFB1AD, SFB2AD registers to select
+	 * the chip we want to access.
+	 */
+	for (i = 0; i < 4; i++) {
+		if (i < spi->chip_select)
+			map_addr = q->memmap_phy;
+		else
+			map_addr = q->memmap_phy +
+				   2 * q->devtype_data->ahb_buf_size;
+
+		q->write(map_addr, q->iobase + QUADSPI_SFA1AD + (i * 4));
+	}
+
+	if (needs_4x_clock(q))
+		rate *= 4;
+
+	fsl_qspi_clk_disable_unprep(q);
+
+	ret = clk_set_rate(q->clk, rate);
+	if (ret)
+		return;
+
+	ret = fsl_qspi_clk_prep_enable(q);
+	if (ret)
+		return;
+
+	q->selected = spi->chip_select;
+}
+
+static void fsl_qspi_read_ahb(struct fsl_qspi *q, const struct spi_mem_op *op)
+{
+	/*
+	 * We want to avoid needing to invalidate the cache by issueing
+	 * a reset to the AHB and Serial Flash domain, as this needs
+	 * time. So we change the address on each read to trigger an
+	 * actual read operation on the flash. The actual address for
+	 * the flash memory is set by programming the LUT.
+	 */
+	memcpy_fromio(op->data.buf.in,
+		      q->ahb_addr +
+		      (((q->seq & (1 << q->selected)) == 0 ? 0:1) *
+		       q->devtype_data->ahb_buf_size),
+		      op->data.nbytes);
+
+	q->seq ^= 1 << q->selected;
+}
+
+static void fsl_qspi_fill_txfifo(struct fsl_qspi *q,
+				 const struct spi_mem_op *op)
+{
+	void __iomem *base = q->iobase;
+	int i;
+	u32 val;
+
+	for (i = 0; i < ALIGN_DOWN(op->data.nbytes, 4); i += 4) {
+		memcpy(&val, op->data.buf.out + i, 4);
+		val = fsl_qspi_endian_xchg(q, val);
+		q->write(val, base + QUADSPI_TBDR);
+	}
+
+	if (i < op->data.nbytes) {
+		memcpy(&val, op->data.buf.out + i, op->data.nbytes - i);
+		val = fsl_qspi_endian_xchg(q, val);
+		q->write(val, base + QUADSPI_TBDR);
+	}
+
+	if (needs_fill_txfifo(q)) {
+		for (i = op->data.nbytes; i < 16; i += 4)
+			q->write(0, base + QUADSPI_TBDR);
+	}
+}
+
+static void fsl_qspi_read_rxfifo(struct fsl_qspi *q,
+			  const struct spi_mem_op *op)
+{
+	void __iomem *base = q->iobase;
+	int i;
+	u8 *buf = op->data.buf.in;
+	u32 val;
+
+	for (i = 0; i < ALIGN_DOWN(op->data.nbytes, 4); i += 4) {
+		val = q->read(base + QUADSPI_RBDR(i / 4));
+		val = fsl_qspi_endian_xchg(q, val);
+		memcpy(buf + i, &val, 4);
+	}
+
+	if (i < op->data.nbytes) {
+		val = q->read(base + QUADSPI_RBDR(i / 4));
+		val = fsl_qspi_endian_xchg(q, val);
+		memcpy(buf + i, &val, op->data.nbytes - i);
+	}
+}
+
+static int fsl_qspi_do_op(struct fsl_qspi *q, const struct spi_mem_op *op)
+{
+	void __iomem *base = q->iobase;
+	int err = 0;
+
+	init_completion(&q->c);
+
+	/*
+	 * Always start the sequence at the same index since we update
+	 * the LUT at each exec_op() call. And also specify the DATA
+	 * length, since it's has not been specified in the LUT.
+	 */
+	q->write(op->data.nbytes |
+		    (SEQID_LUT << QUADSPI_IPCR_SEQID_SHIFT),
+		    base + QUADSPI_IPCR);
+
+	/* Wait for the interrupt. */
+	if (!wait_for_completion_timeout(&q->c, msecs_to_jiffies(1000)))
+		err = -ETIMEDOUT;
+
+	if (!err && op->data.nbytes && op->data.dir == SPI_MEM_DATA_IN)
+		fsl_qspi_read_rxfifo(q, op);
+
+	return err;
+}
+
+static int fsl_qspi_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
+{
+	struct fsl_qspi *q = spi_controller_get_devdata(mem->spi->master);
+	void __iomem *base = q->iobase;
+	int err = 0;
+	unsigned int timeout = 1000;
+
+	mutex_lock(&q->lock);
+
+	/* wait for the controller being ready */
+	do {
+		u32 status;
+
+		status = q->read(base + QUADSPI_SR);
+		if (status &
+		    (QUADSPI_SR_IP_ACC_MASK | QUADSPI_SR_AHB_ACC_MASK)) {
+			udelay(1);
+			dev_dbg(q->dev, "The controller is busy, 0x%x\n",
+				status);
+			continue;
+		}
+		break;
+	} while (--timeout);
+
+	fsl_qspi_select_mem(q, mem->spi);
+
+	q->write(q->memmap_phy, base + QUADSPI_SFAR);
+
+	q->write(q->read(base + QUADSPI_MCR) |
+		 QUADSPI_MCR_CLR_RXF_MASK | QUADSPI_MCR_CLR_TXF_MASK,
+		 base + QUADSPI_MCR);
+
+	q->write(QUADSPI_SPTRCLR_BFPTRC | QUADSPI_SPTRCLR_IPPTRC,
+		    base + QUADSPI_SPTRCLR);
+
+	fsl_qspi_prepare_lut(q, op);
+
+	/*
+	 * If we have large chunks of data, we read them through the AHB bus
+	 * by accessing the mapped memory. In all other cases we use
+	 * IP commands to access the flash.
+	 */
+	if (op->data.nbytes > (q->devtype_data->rxfifo - 4) &&
+	    op->data.dir == SPI_MEM_DATA_IN) {
+		fsl_qspi_read_ahb(q, op);
+	} else {
+		q->write(QUADSPI_RBCT_WMRK_MASK | QUADSPI_RBCT_RXBRD_USEIPS,
+			 base + QUADSPI_RBCT);
+
+		if (op->data.nbytes && op->data.dir == SPI_MEM_DATA_OUT)
+			fsl_qspi_fill_txfifo(q, op);
+
+		err = fsl_qspi_do_op(q, op);
+	}
+
+	mutex_unlock(&q->lock);
+
+	return err;
+}
+
+static int fsl_qspi_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
+{
+	struct fsl_qspi *q = spi_controller_get_devdata(mem->spi->master);
+
+	if (op->data.dir == SPI_MEM_DATA_OUT) {
+		if (op->data.nbytes > q->devtype_data->txfifo)
+			op->data.nbytes = q->devtype_data->txfifo;
+	} else {
+		if (op->data.nbytes > q->devtype_data->ahb_buf_size)
+			op->data.nbytes = q->devtype_data->ahb_buf_size;
+		else if (op->data.nbytes > (q->devtype_data->rxfifo - 4))
+			op->data.nbytes = ALIGN_DOWN(op->data.nbytes, 8);
+	}
+
+	return 0;
+}
+
+static int fsl_qspi_default_setup(struct fsl_qspi *q)
+{
+	void __iomem *base = q->iobase;
+	u32 reg;
+	int ret;
+
+	/* disable and unprepare clock to avoid glitch pass to controller */
+	fsl_qspi_clk_disable_unprep(q);
+
+	/* the default frequency, we will change it later if necessary. */
+	ret = clk_set_rate(q->clk, 66000000);
+	if (ret)
+		return ret;
+
+	ret = fsl_qspi_clk_prep_enable(q);
+	if (ret)
+		return ret;
+
+	/* Reset the module */
+	q->write(QUADSPI_MCR_SWRSTSD_MASK | QUADSPI_MCR_SWRSTHD_MASK,
+		 base + QUADSPI_MCR);
+	udelay(1);
+
+	/* Disable the module */
+	q->write(QUADSPI_MCR_MDIS_MASK | QUADSPI_MCR_RESERVED_MASK,
+		 base + QUADSPI_MCR);
+
+	reg = q->read(base + QUADSPI_SMPR);
+	q->write(reg & ~(QUADSPI_SMPR_FSDLY_MASK
+			| QUADSPI_SMPR_FSPHS_MASK
+			| QUADSPI_SMPR_HSENA_MASK
+			| QUADSPI_SMPR_DDRSMP_MASK), base + QUADSPI_SMPR);
+
+	/* We only use the buffer3 for AHB read */
+	q->write(0, base + QUADSPI_BUF0IND);
+	q->write(0, base + QUADSPI_BUF1IND);
+	q->write(0, base + QUADSPI_BUF2IND);
+
+	q->write(SEQID_LUT << QUADSPI_BFGENCR_SEQID_SHIFT,
+		 q->iobase + QUADSPI_BFGENCR);
+	q->write(QUADSPI_RBCT_WMRK_MASK, base + QUADSPI_RBCT);
+	q->write(QUADSPI_BUF3CR_ALLMST_MASK |
+		 ((q->devtype_data->ahb_buf_size / 8) <<
+		  QUADSPI_BUF3CR_ADATSZ_SHIFT),
+		 base + QUADSPI_BUF3CR);
+
+	q->selected = -1;
+	q->seq = 0;
+
+	/* Enable the module */
+	q->write(QUADSPI_MCR_RESERVED_MASK | QUADSPI_MCR_END_CFG_MASK,
+		 base + QUADSPI_MCR);
+
+	/* clear all interrupt status */
+	q->write(0xffffffff, q->iobase + QUADSPI_FR);
+
+	/* enable the interrupt */
+	q->write(QUADSPI_RSER_TFIE, q->iobase + QUADSPI_RSER);
+
+	return 0;
+}
+
+static const char *fsl_qspi_get_name(struct spi_mem *mem)
+{
+	struct fsl_qspi *q = spi_controller_get_devdata(mem->spi->master);
+	struct device *dev = &mem->spi->dev;
+	const char *name;
+
+	/*
+	 * In order to keep mtdparts compatible with the old MTD driver at
+	 * mtd/spi-nor/fsl-quadspi.c, we set a custom name derived from the
+	 * platform_device of the controller.
+	 */
+	if (of_get_available_child_count(q->dev->of_node) == 1)
+		return dev_name(q->dev);
+
+	name = devm_kasprintf(dev, GFP_KERNEL,
+			      "%s-%d", dev_name(q->dev),
+			      mem->spi->chip_select);
+
+	if (!name) {
+		dev_err(dev, "failed to get memory for custom flash name\n");
+		return ERR_PTR(-ENOMEM);
+	}
+
+	return name;
+}
+
+static const struct spi_controller_mem_ops fsl_qspi_mem_ops = {
+	.adjust_op_size = fsl_qspi_adjust_op_size,
+	.supports_op = fsl_qspi_supports_op,
+	.exec_op = fsl_qspi_exec_op,
+	.get_name = fsl_qspi_get_name,
+};
+
+static int fsl_qspi_probe(struct platform_device *pdev)
+{
+	struct spi_controller *ctlr;
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	struct resource *res;
+	struct fsl_qspi *q;
+	int ret;
+
+	ctlr = spi_alloc_master(&pdev->dev, sizeof(*q));
+	if (!ctlr)
+		return -ENOMEM;
+
+	ctlr->mode_bits = SPI_RX_DUAL | SPI_RX_QUAD |
+			  SPI_TX_DUAL | SPI_TX_QUAD;
+
+	q = spi_controller_get_devdata(ctlr);
+	q->dev = dev;
+	q->devtype_data = of_device_get_match_data(dev);
+	if (!q->devtype_data) {
+		ret = -ENODEV;
+		goto err_put_ctrl;
+	}
+
+	platform_set_drvdata(pdev, q);
+
+	/* find the resources */
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "QuadSPI");
+	q->iobase = devm_ioremap_resource(dev, res);
+	if (IS_ERR(q->iobase)) {
+		ret = PTR_ERR(q->iobase);
+		goto err_put_ctrl;
+	}
+
+	/*
+	 * R/W functions for big- or little-endian registers:
+	 * The QSPI controller's endianness is independent of
+	 * the CPU core's endianness. So far, although the CPU
+	 * core is little-endian the QSPI controller can use
+	 * big-endian or little-endian.
+	 */
+	if (of_property_read_bool(np, "big-endian")) {
+		q->write = qspi_writel_be;
+		q->read = qspi_readl_be;
+	} else {
+		q->write = qspi_writel;
+		q->read = qspi_readl;
+	}
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
+					"QuadSPI-memory");
+	q->ahb_addr = devm_ioremap_resource(dev, res);
+	if (IS_ERR(q->ahb_addr)) {
+		ret = PTR_ERR(q->ahb_addr);
+		goto err_put_ctrl;
+	}
+
+	q->memmap_phy = res->start;
+
+	/* find the clocks */
+	q->clk_en = devm_clk_get(dev, "qspi_en");
+	if (IS_ERR(q->clk_en)) {
+		ret = PTR_ERR(q->clk_en);
+		goto err_put_ctrl;
+	}
+
+	q->clk = devm_clk_get(dev, "qspi");
+	if (IS_ERR(q->clk)) {
+		ret = PTR_ERR(q->clk);
+		goto err_put_ctrl;
+	}
+
+	ret = fsl_qspi_clk_prep_enable(q);
+	if (ret) {
+		dev_err(dev, "can not enable the clock\n");
+		goto err_put_ctrl;
+	}
+
+	/* find the irq */
+	ret = platform_get_irq(pdev, 0);
+	if (ret < 0) {
+		dev_err(dev, "failed to get the irq: %d\n", ret);
+		goto err_disable_clk;
+	}
+
+	ret = devm_request_irq(dev, ret,
+			fsl_qspi_irq_handler, 0, pdev->name, q);
+	if (ret) {
+		dev_err(dev, "failed to request irq: %d\n", ret);
+		goto err_disable_clk;
+	}
+
+	mutex_init(&q->lock);
+
+	ctlr->bus_num = -1;
+	ctlr->num_chipselect = 4;
+	ctlr->mem_ops = &fsl_qspi_mem_ops;
+
+	fsl_qspi_default_setup(q);
+
+	ctlr->dev.of_node = np;
+
+	ret = spi_register_controller(ctlr);
+	if (ret)
+		goto err_destroy_mutex;
+
+	return 0;
+
+err_destroy_mutex:
+	mutex_destroy(&q->lock);
+
+err_disable_clk:
+	fsl_qspi_clk_disable_unprep(q);
+
+err_put_ctrl:
+	spi_controller_put(ctlr);
+
+	dev_err(dev, "Freescale QuadSPI probe failed\n");
+	return ret;
+}
+
+static int fsl_qspi_remove(struct platform_device *pdev)
+{
+	struct fsl_qspi *q = platform_get_drvdata(pdev);
+
+	/* disable the hardware */
+	q->write(QUADSPI_MCR_MDIS_MASK, q->iobase + QUADSPI_MCR);
+	q->write(0x0, q->iobase + QUADSPI_RSER);
+
+	fsl_qspi_clk_disable_unprep(q);
+
+	mutex_destroy(&q->lock);
+
+	return 0;
+}
+
+static int fsl_qspi_suspend(struct device *dev)
+{
+	return 0;
+}
+
+static int fsl_qspi_resume(struct device *dev)
+{
+	struct fsl_qspi *q = dev_get_drvdata(dev);
+
+	fsl_qspi_default_setup(q);
+
+	return 0;
+}
+
+static const struct of_device_id fsl_qspi_dt_ids[] = {
+	{ .compatible = "fsl,vf610-qspi", .data = &vybrid_data, },
+	{ .compatible = "fsl,imx6sx-qspi", .data = &imx6sx_data, },
+	{ .compatible = "fsl,imx7d-qspi", .data = &imx7d_data, },
+	{ .compatible = "fsl,imx6ul-qspi", .data = &imx6ul_data, },
+	{ .compatible = "fsl,ls1021a-qspi", .data = &ls1021a_data, },
+	{ .compatible = "fsl,ls2080a-qspi", .data = &ls2080a_data, },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, fsl_qspi_dt_ids);
+
+static const struct dev_pm_ops fsl_qspi_pm_ops = {
+	.suspend	= fsl_qspi_suspend,
+	.resume		= fsl_qspi_resume,
+};
+
+static struct platform_driver fsl_qspi_driver = {
+	.driver = {
+		.name	= "fsl-quadspi",
+		.of_match_table = fsl_qspi_dt_ids,
+		.pm =   &fsl_qspi_pm_ops,
+	},
+	.probe          = fsl_qspi_probe,
+	.remove		= fsl_qspi_remove,
+};
+module_platform_driver(fsl_qspi_driver);
+
+MODULE_DESCRIPTION("Freescale QuadSPI Controller Driver");
+MODULE_AUTHOR("Freescale Semiconductor Inc.");
+MODULE_AUTHOR("Boris Brezillion <boris.brezillon at bootlin.com>");
+MODULE_AUTHOR("Frieder Schrempf <frieder.schrempf at exceet.de>");
+MODULE_AUTHOR("Yogesh Gaur <yogeshnarayan.gaur at nxp.com>");
+MODULE_AUTHOR("Suresh Gupta <suresh.gupta at nxp.com>");
+MODULE_LICENSE("GPL v2");
-- 
2.7.4