Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/spi/spi-nxp-fspi.c b/drivers/spi/spi-nxp-fspi.c
new file mode 100644
index 0000000..501b923
--- /dev/null
+++ b/drivers/spi/spi-nxp-fspi.c
@@ -0,0 +1,1104 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+/*
+ * NXP FlexSPI(FSPI) controller driver.
+ *
+ * Copyright 2019 NXP.
+ *
+ * FlexSPI is a flexsible SPI host controller which supports two SPI
+ * channels and up to 4 external devices. Each channel supports
+ * Single/Dual/Quad/Octal mode data transfer (1/2/4/8 bidirectional
+ * data lines).
+ *
+ * FlexSPI controller is driven by the LUT(Look-up Table) registers
+ * LUT registers are a look-up-table for sequences of instructions.
+ * A valid sequence consists of four LUT registers.
+ * Maximum 32 LUT sequences can be programmed simultaneously.
+ *
+ * LUTs are being created at run-time based on the commands passed
+ * from the spi-mem framework, thus using single LUT index.
+ *
+ * Software triggered Flash read/write access by IP Bus.
+ *
+ * Memory mapped read access by AHB Bus.
+ *
+ * Based on SPI MEM interface and spi-fsl-qspi.c driver.
+ *
+ * Author:
+ *     Yogesh Narayan Gaur <yogeshnarayan.gaur@nxp.com>
+ *     Boris Brezillon <bbrezillon@kernel.org>
+ *     Frieder Schrempf <frieder.schrempf@kontron.de>
+ */
+
+#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/iopoll.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 (31).
+ */
+#define	SEQID_LUT			31
+
+/* Registers used by the driver */
+#define FSPI_MCR0			0x00
+#define FSPI_MCR0_AHB_TIMEOUT(x)	((x) << 24)
+#define FSPI_MCR0_IP_TIMEOUT(x)		((x) << 16)
+#define FSPI_MCR0_LEARN_EN		BIT(15)
+#define FSPI_MCR0_SCRFRUN_EN		BIT(14)
+#define FSPI_MCR0_OCTCOMB_EN		BIT(13)
+#define FSPI_MCR0_DOZE_EN		BIT(12)
+#define FSPI_MCR0_HSEN			BIT(11)
+#define FSPI_MCR0_SERCLKDIV		BIT(8)
+#define FSPI_MCR0_ATDF_EN		BIT(7)
+#define FSPI_MCR0_ARDF_EN		BIT(6)
+#define FSPI_MCR0_RXCLKSRC(x)		((x) << 4)
+#define FSPI_MCR0_END_CFG(x)		((x) << 2)
+#define FSPI_MCR0_MDIS			BIT(1)
+#define FSPI_MCR0_SWRST			BIT(0)
+
+#define FSPI_MCR1			0x04
+#define FSPI_MCR1_SEQ_TIMEOUT(x)	((x) << 16)
+#define FSPI_MCR1_AHB_TIMEOUT(x)	(x)
+
+#define FSPI_MCR2			0x08
+#define FSPI_MCR2_IDLE_WAIT(x)		((x) << 24)
+#define FSPI_MCR2_SAMEDEVICEEN		BIT(15)
+#define FSPI_MCR2_CLRLRPHS		BIT(14)
+#define FSPI_MCR2_ABRDATSZ		BIT(8)
+#define FSPI_MCR2_ABRLEARN		BIT(7)
+#define FSPI_MCR2_ABR_READ		BIT(6)
+#define FSPI_MCR2_ABRWRITE		BIT(5)
+#define FSPI_MCR2_ABRDUMMY		BIT(4)
+#define FSPI_MCR2_ABR_MODE		BIT(3)
+#define FSPI_MCR2_ABRCADDR		BIT(2)
+#define FSPI_MCR2_ABRRADDR		BIT(1)
+#define FSPI_MCR2_ABR_CMD		BIT(0)
+
+#define FSPI_AHBCR			0x0c
+#define FSPI_AHBCR_RDADDROPT		BIT(6)
+#define FSPI_AHBCR_PREF_EN		BIT(5)
+#define FSPI_AHBCR_BUFF_EN		BIT(4)
+#define FSPI_AHBCR_CACH_EN		BIT(3)
+#define FSPI_AHBCR_CLRTXBUF		BIT(2)
+#define FSPI_AHBCR_CLRRXBUF		BIT(1)
+#define FSPI_AHBCR_PAR_EN		BIT(0)
+
+#define FSPI_INTEN			0x10
+#define FSPI_INTEN_SCLKSBWR		BIT(9)
+#define FSPI_INTEN_SCLKSBRD		BIT(8)
+#define FSPI_INTEN_DATALRNFL		BIT(7)
+#define FSPI_INTEN_IPTXWE		BIT(6)
+#define FSPI_INTEN_IPRXWA		BIT(5)
+#define FSPI_INTEN_AHBCMDERR		BIT(4)
+#define FSPI_INTEN_IPCMDERR		BIT(3)
+#define FSPI_INTEN_AHBCMDGE		BIT(2)
+#define FSPI_INTEN_IPCMDGE		BIT(1)
+#define FSPI_INTEN_IPCMDDONE		BIT(0)
+
+#define FSPI_INTR			0x14
+#define FSPI_INTR_SCLKSBWR		BIT(9)
+#define FSPI_INTR_SCLKSBRD		BIT(8)
+#define FSPI_INTR_DATALRNFL		BIT(7)
+#define FSPI_INTR_IPTXWE		BIT(6)
+#define FSPI_INTR_IPRXWA		BIT(5)
+#define FSPI_INTR_AHBCMDERR		BIT(4)
+#define FSPI_INTR_IPCMDERR		BIT(3)
+#define FSPI_INTR_AHBCMDGE		BIT(2)
+#define FSPI_INTR_IPCMDGE		BIT(1)
+#define FSPI_INTR_IPCMDDONE		BIT(0)
+
+#define FSPI_LUTKEY			0x18
+#define FSPI_LUTKEY_VALUE		0x5AF05AF0
+
+#define FSPI_LCKCR			0x1C
+
+#define FSPI_LCKER_LOCK			0x1
+#define FSPI_LCKER_UNLOCK		0x2
+
+#define FSPI_BUFXCR_INVALID_MSTRID	0xE
+#define FSPI_AHBRX_BUF0CR0		0x20
+#define FSPI_AHBRX_BUF1CR0		0x24
+#define FSPI_AHBRX_BUF2CR0		0x28
+#define FSPI_AHBRX_BUF3CR0		0x2C
+#define FSPI_AHBRX_BUF4CR0		0x30
+#define FSPI_AHBRX_BUF5CR0		0x34
+#define FSPI_AHBRX_BUF6CR0		0x38
+#define FSPI_AHBRX_BUF7CR0		0x3C
+#define FSPI_AHBRXBUF0CR7_PREF		BIT(31)
+
+#define FSPI_AHBRX_BUF0CR1		0x40
+#define FSPI_AHBRX_BUF1CR1		0x44
+#define FSPI_AHBRX_BUF2CR1		0x48
+#define FSPI_AHBRX_BUF3CR1		0x4C
+#define FSPI_AHBRX_BUF4CR1		0x50
+#define FSPI_AHBRX_BUF5CR1		0x54
+#define FSPI_AHBRX_BUF6CR1		0x58
+#define FSPI_AHBRX_BUF7CR1		0x5C
+
+#define FSPI_FLSHA1CR0			0x60
+#define FSPI_FLSHA2CR0			0x64
+#define FSPI_FLSHB1CR0			0x68
+#define FSPI_FLSHB2CR0			0x6C
+#define FSPI_FLSHXCR0_SZ_KB		10
+#define FSPI_FLSHXCR0_SZ(x)		((x) >> FSPI_FLSHXCR0_SZ_KB)
+
+#define FSPI_FLSHA1CR1			0x70
+#define FSPI_FLSHA2CR1			0x74
+#define FSPI_FLSHB1CR1			0x78
+#define FSPI_FLSHB2CR1			0x7C
+#define FSPI_FLSHXCR1_CSINTR(x)		((x) << 16)
+#define FSPI_FLSHXCR1_CAS(x)		((x) << 11)
+#define FSPI_FLSHXCR1_WA		BIT(10)
+#define FSPI_FLSHXCR1_TCSH(x)		((x) << 5)
+#define FSPI_FLSHXCR1_TCSS(x)		(x)
+
+#define FSPI_FLSHA1CR2			0x80
+#define FSPI_FLSHA2CR2			0x84
+#define FSPI_FLSHB1CR2			0x88
+#define FSPI_FLSHB2CR2			0x8C
+#define FSPI_FLSHXCR2_CLRINSP		BIT(24)
+#define FSPI_FLSHXCR2_AWRWAIT		BIT(16)
+#define FSPI_FLSHXCR2_AWRSEQN_SHIFT	13
+#define FSPI_FLSHXCR2_AWRSEQI_SHIFT	8
+#define FSPI_FLSHXCR2_ARDSEQN_SHIFT	5
+#define FSPI_FLSHXCR2_ARDSEQI_SHIFT	0
+
+#define FSPI_IPCR0			0xA0
+
+#define FSPI_IPCR1			0xA4
+#define FSPI_IPCR1_IPAREN		BIT(31)
+#define FSPI_IPCR1_SEQNUM_SHIFT		24
+#define FSPI_IPCR1_SEQID_SHIFT		16
+#define FSPI_IPCR1_IDATSZ(x)		(x)
+
+#define FSPI_IPCMD			0xB0
+#define FSPI_IPCMD_TRG			BIT(0)
+
+#define FSPI_DLPR			0xB4
+
+#define FSPI_IPRXFCR			0xB8
+#define FSPI_IPRXFCR_CLR		BIT(0)
+#define FSPI_IPRXFCR_DMA_EN		BIT(1)
+#define FSPI_IPRXFCR_WMRK(x)		((x) << 2)
+
+#define FSPI_IPTXFCR			0xBC
+#define FSPI_IPTXFCR_CLR		BIT(0)
+#define FSPI_IPTXFCR_DMA_EN		BIT(1)
+#define FSPI_IPTXFCR_WMRK(x)		((x) << 2)
+
+#define FSPI_DLLACR			0xC0
+#define FSPI_DLLACR_OVRDEN		BIT(8)
+
+#define FSPI_DLLBCR			0xC4
+#define FSPI_DLLBCR_OVRDEN		BIT(8)
+
+#define FSPI_STS0			0xE0
+#define FSPI_STS0_DLPHB(x)		((x) << 8)
+#define FSPI_STS0_DLPHA(x)		((x) << 4)
+#define FSPI_STS0_CMD_SRC(x)		((x) << 2)
+#define FSPI_STS0_ARB_IDLE		BIT(1)
+#define FSPI_STS0_SEQ_IDLE		BIT(0)
+
+#define FSPI_STS1			0xE4
+#define FSPI_STS1_IP_ERRCD(x)		((x) << 24)
+#define FSPI_STS1_IP_ERRID(x)		((x) << 16)
+#define FSPI_STS1_AHB_ERRCD(x)		((x) << 8)
+#define FSPI_STS1_AHB_ERRID(x)		(x)
+
+#define FSPI_AHBSPNST			0xEC
+#define FSPI_AHBSPNST_DATLFT(x)		((x) << 16)
+#define FSPI_AHBSPNST_BUFID(x)		((x) << 1)
+#define FSPI_AHBSPNST_ACTIVE		BIT(0)
+
+#define FSPI_IPRXFSTS			0xF0
+#define FSPI_IPRXFSTS_RDCNTR(x)		((x) << 16)
+#define FSPI_IPRXFSTS_FILL(x)		(x)
+
+#define FSPI_IPTXFSTS			0xF4
+#define FSPI_IPTXFSTS_WRCNTR(x)		((x) << 16)
+#define FSPI_IPTXFSTS_FILL(x)		(x)
+
+#define FSPI_RFDR			0x100
+#define FSPI_TFDR			0x180
+
+#define FSPI_LUT_BASE			0x200
+#define FSPI_LUT_OFFSET			(SEQID_LUT * 4 * 4)
+#define FSPI_LUT_REG(idx) \
+	(FSPI_LUT_BASE + FSPI_LUT_OFFSET + (idx) * 4)
+
+/* register map end */
+
+/* Instruction set for the LUT register. */
+#define LUT_STOP			0x00
+#define LUT_CMD				0x01
+#define LUT_ADDR			0x02
+#define LUT_CADDR_SDR			0x03
+#define LUT_MODE			0x04
+#define LUT_MODE2			0x05
+#define LUT_MODE4			0x06
+#define LUT_MODE8			0x07
+#define LUT_NXP_WRITE			0x08
+#define LUT_NXP_READ			0x09
+#define LUT_LEARN_SDR			0x0A
+#define LUT_DATSZ_SDR			0x0B
+#define LUT_DUMMY			0x0C
+#define LUT_DUMMY_RWDS_SDR		0x0D
+#define LUT_JMP_ON_CS			0x1F
+#define LUT_CMD_DDR			0x21
+#define LUT_ADDR_DDR			0x22
+#define LUT_CADDR_DDR			0x23
+#define LUT_MODE_DDR			0x24
+#define LUT_MODE2_DDR			0x25
+#define LUT_MODE4_DDR			0x26
+#define LUT_MODE8_DDR			0x27
+#define LUT_WRITE_DDR			0x28
+#define LUT_READ_DDR			0x29
+#define LUT_LEARN_DDR			0x2A
+#define LUT_DATSZ_DDR			0x2B
+#define LUT_DUMMY_DDR			0x2C
+#define LUT_DUMMY_RWDS_DDR		0x2D
+
+/*
+ * Calculate number of required PAD bits for LUT register.
+ *
+ * The pad stands for the number of IO lines [0:7].
+ * For example, the octal read needs eight IO lines,
+ * so you should use LUT_PAD(8). This macro
+ * returns 3 i.e. use eight (2^3) IP lines for read.
+ */
+#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 PAD_SHIFT		8
+#define INSTR_SHIFT		10
+#define OPRND_SHIFT		16
+
+/* Macros for constructing the LUT register. */
+#define LUT_DEF(idx, ins, pad, opr)			  \
+	((((ins) << INSTR_SHIFT) | ((pad) << PAD_SHIFT) | \
+	(opr)) << (((idx) % 2) * OPRND_SHIFT))
+
+#define POLL_TOUT		5000
+#define NXP_FSPI_MAX_CHIPSELECT		4
+
+struct nxp_fspi_devtype_data {
+	unsigned int rxfifo;
+	unsigned int txfifo;
+	unsigned int ahb_buf_size;
+	unsigned int quirks;
+	bool little_endian;
+};
+
+static const struct nxp_fspi_devtype_data lx2160a_data = {
+	.rxfifo = SZ_512,       /* (64  * 64 bits)  */
+	.txfifo = SZ_1K,        /* (128 * 64 bits)  */
+	.ahb_buf_size = SZ_2K,  /* (256 * 64 bits)  */
+	.quirks = 0,
+	.little_endian = true,  /* little-endian    */
+};
+
+struct nxp_fspi {
+	void __iomem *iobase;
+	void __iomem *ahb_addr;
+	u32 memmap_phy;
+	u32 memmap_phy_size;
+	struct clk *clk, *clk_en;
+	struct device *dev;
+	struct completion c;
+	const struct nxp_fspi_devtype_data *devtype_data;
+	struct mutex lock;
+	struct pm_qos_request pm_qos_req;
+	int selected;
+};
+
+/*
+ * R/W functions for big- or little-endian registers:
+ * The FSPI controller's endianness is independent of
+ * the CPU core's endianness. So far, although the CPU
+ * core is little-endian the FSPI controller can use
+ * big-endian or little-endian.
+ */
+static void fspi_writel(struct nxp_fspi *f, u32 val, void __iomem *addr)
+{
+	if (f->devtype_data->little_endian)
+		iowrite32(val, addr);
+	else
+		iowrite32be(val, addr);
+}
+
+static u32 fspi_readl(struct nxp_fspi *f, void __iomem *addr)
+{
+	if (f->devtype_data->little_endian)
+		return ioread32(addr);
+	else
+		return ioread32be(addr);
+}
+
+static irqreturn_t nxp_fspi_irq_handler(int irq, void *dev_id)
+{
+	struct nxp_fspi *f = dev_id;
+	u32 reg;
+
+	/* clear interrupt */
+	reg = fspi_readl(f, f->iobase + FSPI_INTR);
+	fspi_writel(f, FSPI_INTR_IPCMDDONE, f->iobase + FSPI_INTR);
+
+	if (reg & FSPI_INTR_IPCMDDONE)
+		complete(&f->c);
+
+	return IRQ_HANDLED;
+}
+
+static int nxp_fspi_check_buswidth(struct nxp_fspi *f, u8 width)
+{
+	switch (width) {
+	case 1:
+	case 2:
+	case 4:
+	case 8:
+		return 0;
+	}
+
+	return -ENOTSUPP;
+}
+
+static bool nxp_fspi_supports_op(struct spi_mem *mem,
+				 const struct spi_mem_op *op)
+{
+	struct nxp_fspi *f = spi_controller_get_devdata(mem->spi->master);
+	int ret;
+
+	ret = nxp_fspi_check_buswidth(f, op->cmd.buswidth);
+
+	if (op->addr.nbytes)
+		ret |= nxp_fspi_check_buswidth(f, op->addr.buswidth);
+
+	if (op->dummy.nbytes)
+		ret |= nxp_fspi_check_buswidth(f, op->dummy.buswidth);
+
+	if (op->data.nbytes)
+		ret |= nxp_fspi_check_buswidth(f, op->data.buswidth);
+
+	if (ret)
+		return false;
+
+	/*
+	 * The number of address bytes should be equal to or less than 4 bytes.
+	 */
+	if (op->addr.nbytes > 4)
+		return false;
+
+	/*
+	 * If requested address value is greater than controller assigned
+	 * memory mapped space, return error as it didn't fit in the range
+	 * of assigned address space.
+	 */
+	if (op->addr.val >= f->memmap_phy_size)
+		return false;
+
+	/* Max 64 dummy clock cycles supported */
+	if (op->dummy.buswidth &&
+	    (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 > f->devtype_data->ahb_buf_size ||
+	     (op->data.nbytes > f->devtype_data->rxfifo - 4 &&
+	      !IS_ALIGNED(op->data.nbytes, 8))))
+		return false;
+
+	if (op->data.dir == SPI_MEM_DATA_OUT &&
+	    op->data.nbytes > f->devtype_data->txfifo)
+		return false;
+
+	return true;
+}
+
+/* Instead of busy looping invoke readl_poll_timeout functionality. */
+static int fspi_readl_poll_tout(struct nxp_fspi *f, void __iomem *base,
+				u32 mask, u32 delay_us,
+				u32 timeout_us, bool c)
+{
+	u32 reg;
+
+	if (!f->devtype_data->little_endian)
+		mask = (u32)cpu_to_be32(mask);
+
+	if (c)
+		return readl_poll_timeout(base, reg, (reg & mask),
+					  delay_us, timeout_us);
+	else
+		return readl_poll_timeout(base, reg, !(reg & mask),
+					  delay_us, timeout_us);
+}
+
+/*
+ * If the slave device content being changed by Write/Erase, need to
+ * invalidate the AHB buffer. This can be achieved by doing the reset
+ * of controller after setting MCR0[SWRESET] bit.
+ */
+static inline void nxp_fspi_invalid(struct nxp_fspi *f)
+{
+	u32 reg;
+	int ret;
+
+	reg = fspi_readl(f, f->iobase + FSPI_MCR0);
+	fspi_writel(f, reg | FSPI_MCR0_SWRST, f->iobase + FSPI_MCR0);
+
+	/* w1c register, wait unit clear */
+	ret = fspi_readl_poll_tout(f, f->iobase + FSPI_MCR0,
+				   FSPI_MCR0_SWRST, 0, POLL_TOUT, false);
+	WARN_ON(ret);
+}
+
+static void nxp_fspi_prepare_lut(struct nxp_fspi *f,
+				 const struct spi_mem_op *op)
+{
+	void __iomem *base = f->iobase;
+	u32 lutval[4] = {};
+	int lutidx = 1, i;
+
+	/* cmd */
+	lutval[0] |= LUT_DEF(0, LUT_CMD, LUT_PAD(op->cmd.buswidth),
+			     op->cmd.opcode);
+
+	/* addr bytes */
+	if (op->addr.nbytes) {
+		lutval[lutidx / 2] |= LUT_DEF(lutidx, LUT_ADDR,
+					      LUT_PAD(op->addr.buswidth),
+					      op->addr.nbytes * 8);
+		lutidx++;
+	}
+
+	/* dummy bytes, if needed */
+	if (op->dummy.nbytes) {
+		lutval[lutidx / 2] |= LUT_DEF(lutidx, LUT_DUMMY,
+		/*
+		 * Due to FlexSPI controller limitation number of PAD for dummy
+		 * buswidth needs to be programmed as equal to data buswidth.
+		 */
+					      LUT_PAD(op->data.buswidth),
+					      op->dummy.nbytes * 8 /
+					      op->dummy.buswidth);
+		lutidx++;
+	}
+
+	/* read/write data bytes */
+	if (op->data.nbytes) {
+		lutval[lutidx / 2] |= LUT_DEF(lutidx,
+					      op->data.dir == SPI_MEM_DATA_IN ?
+					      LUT_NXP_READ : LUT_NXP_WRITE,
+					      LUT_PAD(op->data.buswidth),
+					      0);
+		lutidx++;
+	}
+
+	/* stop condition. */
+	lutval[lutidx / 2] |= LUT_DEF(lutidx, LUT_STOP, 0, 0);
+
+	/* unlock LUT */
+	fspi_writel(f, FSPI_LUTKEY_VALUE, f->iobase + FSPI_LUTKEY);
+	fspi_writel(f, FSPI_LCKER_UNLOCK, f->iobase + FSPI_LCKCR);
+
+	/* fill LUT */
+	for (i = 0; i < ARRAY_SIZE(lutval); i++)
+		fspi_writel(f, lutval[i], base + FSPI_LUT_REG(i));
+
+	dev_dbg(f->dev, "CMD[%x] lutval[0:%x \t 1:%x \t 2:%x \t 3:%x]\n",
+		op->cmd.opcode, lutval[0], lutval[1], lutval[2], lutval[3]);
+
+	/* lock LUT */
+	fspi_writel(f, FSPI_LUTKEY_VALUE, f->iobase + FSPI_LUTKEY);
+	fspi_writel(f, FSPI_LCKER_LOCK, f->iobase + FSPI_LCKCR);
+}
+
+static int nxp_fspi_clk_prep_enable(struct nxp_fspi *f)
+{
+	int ret;
+
+	ret = clk_prepare_enable(f->clk_en);
+	if (ret)
+		return ret;
+
+	ret = clk_prepare_enable(f->clk);
+	if (ret) {
+		clk_disable_unprepare(f->clk_en);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void nxp_fspi_clk_disable_unprep(struct nxp_fspi *f)
+{
+	clk_disable_unprepare(f->clk);
+	clk_disable_unprepare(f->clk_en);
+}
+
+/*
+ * In FlexSPI controller, flash access is based on value of FSPI_FLSHXXCR0
+ * register and start base address of the slave device.
+ *
+ *							    (Higher address)
+ *				--------    <-- FLSHB2CR0
+ *				|  B2  |
+ *				|      |
+ *	B2 start address -->	--------    <-- FLSHB1CR0
+ *				|  B1  |
+ *				|      |
+ *	B1 start address -->	--------    <-- FLSHA2CR0
+ *				|  A2  |
+ *				|      |
+ *	A2 start address -->	--------    <-- FLSHA1CR0
+ *				|  A1  |
+ *				|      |
+ *	A1 start address -->	--------		    (Lower address)
+ *
+ *
+ * Start base address defines the starting address range for given CS and
+ * FSPI_FLSHXXCR0 defines the size of the slave device connected at given CS.
+ *
+ * But, different targets are having different combinations of number of CS,
+ * some targets only have single CS or two CS covering controller's full
+ * memory mapped space area.
+ * Thus, implementation is being done as independent of the size and number
+ * of the connected slave device.
+ * Assign controller memory mapped space size as the size to the connected
+ * slave device.
+ * Mark FLSHxxCR0 as zero initially and then assign value only to the selected
+ * chip-select Flash configuration register.
+ *
+ * For e.g. to access CS2 (B1), FLSHB1CR0 register would be equal to the
+ * memory mapped size of the controller.
+ * Value for rest of the CS FLSHxxCR0 register would be zero.
+ *
+ */
+static void nxp_fspi_select_mem(struct nxp_fspi *f, struct spi_device *spi)
+{
+	unsigned long rate = spi->max_speed_hz;
+	int ret;
+	uint64_t size_kb;
+
+	/*
+	 * Return, if previously selected slave device is same as current
+	 * requested slave device.
+	 */
+	if (f->selected == spi->chip_select)
+		return;
+
+	/* Reset FLSHxxCR0 registers */
+	fspi_writel(f, 0, f->iobase + FSPI_FLSHA1CR0);
+	fspi_writel(f, 0, f->iobase + FSPI_FLSHA2CR0);
+	fspi_writel(f, 0, f->iobase + FSPI_FLSHB1CR0);
+	fspi_writel(f, 0, f->iobase + FSPI_FLSHB2CR0);
+
+	/* Assign controller memory mapped space as size, KBytes, of flash. */
+	size_kb = FSPI_FLSHXCR0_SZ(f->memmap_phy_size);
+
+	fspi_writel(f, size_kb, f->iobase + FSPI_FLSHA1CR0 +
+		    4 * spi->chip_select);
+
+	dev_dbg(f->dev, "Slave device [CS:%x] selected\n", spi->chip_select);
+
+	nxp_fspi_clk_disable_unprep(f);
+
+	ret = clk_set_rate(f->clk, rate);
+	if (ret)
+		return;
+
+	ret = nxp_fspi_clk_prep_enable(f);
+	if (ret)
+		return;
+
+	f->selected = spi->chip_select;
+}
+
+static void nxp_fspi_read_ahb(struct nxp_fspi *f, const struct spi_mem_op *op)
+{
+	u32 len = op->data.nbytes;
+
+	/* Read out the data directly from the AHB buffer. */
+	memcpy_fromio(op->data.buf.in, (f->ahb_addr + op->addr.val), len);
+}
+
+static void nxp_fspi_fill_txfifo(struct nxp_fspi *f,
+				 const struct spi_mem_op *op)
+{
+	void __iomem *base = f->iobase;
+	int i, ret;
+	u8 *buf = (u8 *) op->data.buf.out;
+
+	/* clear the TX FIFO. */
+	fspi_writel(f, FSPI_IPTXFCR_CLR, base + FSPI_IPTXFCR);
+
+	/*
+	 * Default value of water mark level is 8 bytes, hence in single
+	 * write request controller can write max 8 bytes of data.
+	 */
+
+	for (i = 0; i < ALIGN_DOWN(op->data.nbytes, 8); i += 8) {
+		/* Wait for TXFIFO empty */
+		ret = fspi_readl_poll_tout(f, f->iobase + FSPI_INTR,
+					   FSPI_INTR_IPTXWE, 0,
+					   POLL_TOUT, true);
+		WARN_ON(ret);
+
+		fspi_writel(f, *(u32 *) (buf + i), base + FSPI_TFDR);
+		fspi_writel(f, *(u32 *) (buf + i + 4), base + FSPI_TFDR + 4);
+		fspi_writel(f, FSPI_INTR_IPTXWE, base + FSPI_INTR);
+	}
+
+	if (i < op->data.nbytes) {
+		u32 data = 0;
+		int j;
+		/* Wait for TXFIFO empty */
+		ret = fspi_readl_poll_tout(f, f->iobase + FSPI_INTR,
+					   FSPI_INTR_IPTXWE, 0,
+					   POLL_TOUT, true);
+		WARN_ON(ret);
+
+		for (j = 0; j < ALIGN(op->data.nbytes - i, 4); j += 4) {
+			memcpy(&data, buf + i + j, 4);
+			fspi_writel(f, data, base + FSPI_TFDR + j);
+		}
+		fspi_writel(f, FSPI_INTR_IPTXWE, base + FSPI_INTR);
+	}
+}
+
+static void nxp_fspi_read_rxfifo(struct nxp_fspi *f,
+			  const struct spi_mem_op *op)
+{
+	void __iomem *base = f->iobase;
+	int i, ret;
+	int len = op->data.nbytes;
+	u8 *buf = (u8 *) op->data.buf.in;
+
+	/*
+	 * Default value of water mark level is 8 bytes, hence in single
+	 * read request controller can read max 8 bytes of data.
+	 */
+	for (i = 0; i < ALIGN_DOWN(len, 8); i += 8) {
+		/* Wait for RXFIFO available */
+		ret = fspi_readl_poll_tout(f, f->iobase + FSPI_INTR,
+					   FSPI_INTR_IPRXWA, 0,
+					   POLL_TOUT, true);
+		WARN_ON(ret);
+
+		*(u32 *)(buf + i) = fspi_readl(f, base + FSPI_RFDR);
+		*(u32 *)(buf + i + 4) = fspi_readl(f, base + FSPI_RFDR + 4);
+		/* move the FIFO pointer */
+		fspi_writel(f, FSPI_INTR_IPRXWA, base + FSPI_INTR);
+	}
+
+	if (i < len) {
+		u32 tmp;
+		int size, j;
+
+		buf = op->data.buf.in + i;
+		/* Wait for RXFIFO available */
+		ret = fspi_readl_poll_tout(f, f->iobase + FSPI_INTR,
+					   FSPI_INTR_IPRXWA, 0,
+					   POLL_TOUT, true);
+		WARN_ON(ret);
+
+		len = op->data.nbytes - i;
+		for (j = 0; j < op->data.nbytes - i; j += 4) {
+			tmp = fspi_readl(f, base + FSPI_RFDR + j);
+			size = min(len, 4);
+			memcpy(buf + j, &tmp, size);
+			len -= size;
+		}
+	}
+
+	/* invalid the RXFIFO */
+	fspi_writel(f, FSPI_IPRXFCR_CLR, base + FSPI_IPRXFCR);
+	/* move the FIFO pointer */
+	fspi_writel(f, FSPI_INTR_IPRXWA, base + FSPI_INTR);
+}
+
+static int nxp_fspi_do_op(struct nxp_fspi *f, const struct spi_mem_op *op)
+{
+	void __iomem *base = f->iobase;
+	int seqnum = 0;
+	int err = 0;
+	u32 reg;
+
+	reg = fspi_readl(f, base + FSPI_IPRXFCR);
+	/* invalid RXFIFO first */
+	reg &= ~FSPI_IPRXFCR_DMA_EN;
+	reg = reg | FSPI_IPRXFCR_CLR;
+	fspi_writel(f, reg, base + FSPI_IPRXFCR);
+
+	init_completion(&f->c);
+
+	fspi_writel(f, op->addr.val, base + FSPI_IPCR0);
+	/*
+	 * 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.
+	 */
+	fspi_writel(f, op->data.nbytes |
+		 (SEQID_LUT << FSPI_IPCR1_SEQID_SHIFT) |
+		 (seqnum << FSPI_IPCR1_SEQNUM_SHIFT),
+		 base + FSPI_IPCR1);
+
+	/* Trigger the LUT now. */
+	fspi_writel(f, FSPI_IPCMD_TRG, base + FSPI_IPCMD);
+
+	/* Wait for the interrupt. */
+	if (!wait_for_completion_timeout(&f->c, msecs_to_jiffies(1000)))
+		err = -ETIMEDOUT;
+
+	/* Invoke IP data read, if request is of data read. */
+	if (!err && op->data.nbytes && op->data.dir == SPI_MEM_DATA_IN)
+		nxp_fspi_read_rxfifo(f, op);
+
+	return err;
+}
+
+static int nxp_fspi_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
+{
+	struct nxp_fspi *f = spi_controller_get_devdata(mem->spi->master);
+	int err = 0;
+
+	mutex_lock(&f->lock);
+
+	/* Wait for controller being ready. */
+	err = fspi_readl_poll_tout(f, f->iobase + FSPI_STS0,
+				   FSPI_STS0_ARB_IDLE, 1, POLL_TOUT, true);
+	WARN_ON(err);
+
+	nxp_fspi_select_mem(f, mem->spi);
+
+	nxp_fspi_prepare_lut(f, 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 > (f->devtype_data->rxfifo - 4) &&
+	    op->data.dir == SPI_MEM_DATA_IN) {
+		nxp_fspi_read_ahb(f, op);
+	} else {
+		if (op->data.nbytes && op->data.dir == SPI_MEM_DATA_OUT)
+			nxp_fspi_fill_txfifo(f, op);
+
+		err = nxp_fspi_do_op(f, op);
+	}
+
+	/* Invalidate the data in the AHB buffer. */
+	nxp_fspi_invalid(f);
+
+	mutex_unlock(&f->lock);
+
+	return err;
+}
+
+static int nxp_fspi_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
+{
+	struct nxp_fspi *f = spi_controller_get_devdata(mem->spi->master);
+
+	if (op->data.dir == SPI_MEM_DATA_OUT) {
+		if (op->data.nbytes > f->devtype_data->txfifo)
+			op->data.nbytes = f->devtype_data->txfifo;
+	} else {
+		if (op->data.nbytes > f->devtype_data->ahb_buf_size)
+			op->data.nbytes = f->devtype_data->ahb_buf_size;
+		else if (op->data.nbytes > (f->devtype_data->rxfifo - 4))
+			op->data.nbytes = ALIGN_DOWN(op->data.nbytes, 8);
+	}
+
+	return 0;
+}
+
+static int nxp_fspi_default_setup(struct nxp_fspi *f)
+{
+	void __iomem *base = f->iobase;
+	int ret, i;
+	u32 reg;
+
+	/* disable and unprepare clock to avoid glitch pass to controller */
+	nxp_fspi_clk_disable_unprep(f);
+
+	/* the default frequency, we will change it later if necessary. */
+	ret = clk_set_rate(f->clk, 20000000);
+	if (ret)
+		return ret;
+
+	ret = nxp_fspi_clk_prep_enable(f);
+	if (ret)
+		return ret;
+
+	/* Reset the module */
+	/* w1c register, wait unit clear */
+	ret = fspi_readl_poll_tout(f, f->iobase + FSPI_MCR0,
+				   FSPI_MCR0_SWRST, 0, POLL_TOUT, false);
+	WARN_ON(ret);
+
+	/* Disable the module */
+	fspi_writel(f, FSPI_MCR0_MDIS, base + FSPI_MCR0);
+
+	/* Reset the DLL register to default value */
+	fspi_writel(f, FSPI_DLLACR_OVRDEN, base + FSPI_DLLACR);
+	fspi_writel(f, FSPI_DLLBCR_OVRDEN, base + FSPI_DLLBCR);
+
+	/* enable module */
+	fspi_writel(f, FSPI_MCR0_AHB_TIMEOUT(0xFF) | FSPI_MCR0_IP_TIMEOUT(0xFF),
+		 base + FSPI_MCR0);
+
+	/*
+	 * Disable same device enable bit and configure all slave devices
+	 * independently.
+	 */
+	reg = fspi_readl(f, f->iobase + FSPI_MCR2);
+	reg = reg & ~(FSPI_MCR2_SAMEDEVICEEN);
+	fspi_writel(f, reg, base + FSPI_MCR2);
+
+	/* AHB configuration for access buffer 0~7. */
+	for (i = 0; i < 7; i++)
+		fspi_writel(f, 0, base + FSPI_AHBRX_BUF0CR0 + 4 * i);
+
+	/*
+	 * Set ADATSZ with the maximum AHB buffer size to improve the read
+	 * performance.
+	 */
+	fspi_writel(f, (f->devtype_data->ahb_buf_size / 8 |
+		  FSPI_AHBRXBUF0CR7_PREF), base + FSPI_AHBRX_BUF7CR0);
+
+	/* prefetch and no start address alignment limitation */
+	fspi_writel(f, FSPI_AHBCR_PREF_EN | FSPI_AHBCR_RDADDROPT,
+		 base + FSPI_AHBCR);
+
+	/* AHB Read - Set lut sequence ID for all CS. */
+	fspi_writel(f, SEQID_LUT, base + FSPI_FLSHA1CR2);
+	fspi_writel(f, SEQID_LUT, base + FSPI_FLSHA2CR2);
+	fspi_writel(f, SEQID_LUT, base + FSPI_FLSHB1CR2);
+	fspi_writel(f, SEQID_LUT, base + FSPI_FLSHB2CR2);
+
+	f->selected = -1;
+
+	/* enable the interrupt */
+	fspi_writel(f, FSPI_INTEN_IPCMDDONE, base + FSPI_INTEN);
+
+	return 0;
+}
+
+static const char *nxp_fspi_get_name(struct spi_mem *mem)
+{
+	struct nxp_fspi *f = spi_controller_get_devdata(mem->spi->master);
+	struct device *dev = &mem->spi->dev;
+	const char *name;
+
+	// Set custom name derived from the platform_device of the controller.
+	if (of_get_available_child_count(f->dev->of_node) == 1)
+		return dev_name(f->dev);
+
+	name = devm_kasprintf(dev, GFP_KERNEL,
+			      "%s-%d", dev_name(f->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 nxp_fspi_mem_ops = {
+	.adjust_op_size = nxp_fspi_adjust_op_size,
+	.supports_op = nxp_fspi_supports_op,
+	.exec_op = nxp_fspi_exec_op,
+	.get_name = nxp_fspi_get_name,
+};
+
+static int nxp_fspi_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 nxp_fspi *f;
+	int ret;
+
+	ctlr = spi_alloc_master(&pdev->dev, sizeof(*f));
+	if (!ctlr)
+		return -ENOMEM;
+
+	ctlr->mode_bits = SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL |
+			  SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL;
+
+	f = spi_controller_get_devdata(ctlr);
+	f->dev = dev;
+	f->devtype_data = of_device_get_match_data(dev);
+	if (!f->devtype_data) {
+		ret = -ENODEV;
+		goto err_put_ctrl;
+	}
+
+	platform_set_drvdata(pdev, f);
+
+	/* find the resources - configuration register address space */
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "fspi_base");
+	f->iobase = devm_ioremap_resource(dev, res);
+	if (IS_ERR(f->iobase)) {
+		ret = PTR_ERR(f->iobase);
+		goto err_put_ctrl;
+	}
+
+	/* find the resources - controller memory mapped space */
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "fspi_mmap");
+	f->ahb_addr = devm_ioremap_resource(dev, res);
+	if (IS_ERR(f->ahb_addr)) {
+		ret = PTR_ERR(f->ahb_addr);
+		goto err_put_ctrl;
+	}
+
+	/* assign memory mapped starting address and mapped size. */
+	f->memmap_phy = res->start;
+	f->memmap_phy_size = resource_size(res);
+
+	/* find the clocks */
+	f->clk_en = devm_clk_get(dev, "fspi_en");
+	if (IS_ERR(f->clk_en)) {
+		ret = PTR_ERR(f->clk_en);
+		goto err_put_ctrl;
+	}
+
+	f->clk = devm_clk_get(dev, "fspi");
+	if (IS_ERR(f->clk)) {
+		ret = PTR_ERR(f->clk);
+		goto err_put_ctrl;
+	}
+
+	ret = nxp_fspi_clk_prep_enable(f);
+	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)
+		goto err_disable_clk;
+
+	ret = devm_request_irq(dev, ret,
+			nxp_fspi_irq_handler, 0, pdev->name, f);
+	if (ret) {
+		dev_err(dev, "failed to request irq: %d\n", ret);
+		goto err_disable_clk;
+	}
+
+	mutex_init(&f->lock);
+
+	ctlr->bus_num = -1;
+	ctlr->num_chipselect = NXP_FSPI_MAX_CHIPSELECT;
+	ctlr->mem_ops = &nxp_fspi_mem_ops;
+
+	nxp_fspi_default_setup(f);
+
+	ctlr->dev.of_node = np;
+
+	ret = spi_register_controller(ctlr);
+	if (ret)
+		goto err_destroy_mutex;
+
+	return 0;
+
+err_destroy_mutex:
+	mutex_destroy(&f->lock);
+
+err_disable_clk:
+	nxp_fspi_clk_disable_unprep(f);
+
+err_put_ctrl:
+	spi_controller_put(ctlr);
+
+	dev_err(dev, "NXP FSPI probe failed\n");
+	return ret;
+}
+
+static int nxp_fspi_remove(struct platform_device *pdev)
+{
+	struct nxp_fspi *f = platform_get_drvdata(pdev);
+
+	/* disable the hardware */
+	fspi_writel(f, FSPI_MCR0_MDIS, f->iobase + FSPI_MCR0);
+
+	nxp_fspi_clk_disable_unprep(f);
+
+	mutex_destroy(&f->lock);
+
+	return 0;
+}
+
+static int nxp_fspi_suspend(struct device *dev)
+{
+	return 0;
+}
+
+static int nxp_fspi_resume(struct device *dev)
+{
+	struct nxp_fspi *f = dev_get_drvdata(dev);
+
+	nxp_fspi_default_setup(f);
+
+	return 0;
+}
+
+static const struct of_device_id nxp_fspi_dt_ids[] = {
+	{ .compatible = "nxp,lx2160a-fspi", .data = (void *)&lx2160a_data, },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, nxp_fspi_dt_ids);
+
+static const struct dev_pm_ops nxp_fspi_pm_ops = {
+	.suspend	= nxp_fspi_suspend,
+	.resume		= nxp_fspi_resume,
+};
+
+static struct platform_driver nxp_fspi_driver = {
+	.driver = {
+		.name	= "nxp-fspi",
+		.of_match_table = nxp_fspi_dt_ids,
+		.pm =   &nxp_fspi_pm_ops,
+	},
+	.probe          = nxp_fspi_probe,
+	.remove		= nxp_fspi_remove,
+};
+module_platform_driver(nxp_fspi_driver);
+
+MODULE_DESCRIPTION("NXP FSPI Controller Driver");
+MODULE_AUTHOR("NXP Semiconductor");
+MODULE_AUTHOR("Yogesh Narayan Gaur <yogeshnarayan.gaur@nxp.com>");
+MODULE_AUTHOR("Boris Brezillon <bbrezillon@kernel.org>");
+MODULE_AUTHOR("Frieder Schrempf <frieder.schrempf@kontron.de>");
+MODULE_LICENSE("GPL v2");