[RFC PATCH v11 02/10] spi: rockchip-sfc: add rockchip serial flash controller

[Jon Lin <jon.lin@rock-chips.com>]

From: Chris Morgan <macromorgan@hotmail.com>

Add the rockchip serial flash controller (SFC) driver.

Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
Signed-off-by: Jon Lin <jon.lin@rock-chips.com>
---

Changes in v11: None
Changes in v10:
- Fix dma transfer logic

Changes in v9:
- Separate DMA IRQ setting and wait_completion from DMA fifo transfer
  function to make dma_status_poll be possible(Which I will implement
  in u-boot)
- Add SFC Kconfig detail comment

Changes in v8: None
Changes in v7: None
Changes in v6: None
Changes in v5: None
Changes in v4: None
Changes in v3: None
Changes in v2: None
Changes in v1: None

 drivers/spi/Kconfig            |  12 +
 drivers/spi/Makefile           |   1 +
 drivers/spi/spi-rockchip-sfc.c | 681 +++++++++++++++++++++++++++++++++
 3 files changed, 694 insertions(+)
 create mode 100644 drivers/spi/spi-rockchip-sfc.c

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index e71a4c514f7b..83e352b0c8f9 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -658,6 +658,18 @@ config SPI_ROCKCHIP
 	  The main usecase of this controller is to use spi flash as boot
 	  device.
 
+config SPI_ROCKCHIP_SFC
+	tristate "Rockchip Serial Flash Controller (SFC)"
+	depends on ARCH_ROCKCHIP || COMPILE_TEST
+	depends on HAS_IOMEM && HAS_DMA
+	help
+	  This enables support for Rockchip serial flash controller. This
+	  is a specialized controller used to access SPI flash on some
+	  Rockchip SOCs.
+
+	  ROCKCHIP SFC supports DMA and PIO modes. When DMA is not available,
+	  the driver automatically falls back to PIO mode.
+
 config SPI_RB4XX
 	tristate "Mikrotik RB4XX SPI master"
 	depends on SPI_MASTER && ATH79
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 13e54c45e9df..699db95c8441 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -95,6 +95,7 @@ obj-$(CONFIG_SPI_QCOM_GENI)		+= spi-geni-qcom.o
 obj-$(CONFIG_SPI_QCOM_QSPI)		+= spi-qcom-qspi.o
 obj-$(CONFIG_SPI_QUP)			+= spi-qup.o
 obj-$(CONFIG_SPI_ROCKCHIP)		+= spi-rockchip.o
+obj-$(CONFIG_SPI_ROCKCHIP_SFC)		+= spi-rockchip-sfc.o
 obj-$(CONFIG_SPI_RB4XX)			+= spi-rb4xx.o
 obj-$(CONFIG_MACH_REALTEK_RTL)		+= spi-realtek-rtl.o
 obj-$(CONFIG_SPI_RPCIF)			+= spi-rpc-if.o
diff --git a/drivers/spi/spi-rockchip-sfc.c b/drivers/spi/spi-rockchip-sfc.c
new file mode 100644
index 000000000000..28645e6a2204
--- /dev/null
+++ b/drivers/spi/spi-rockchip-sfc.c
@@ -0,0 +1,681 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Rockchip Serial Flash Controller Driver
+ *
+ * Copyright (c) 2017-2021, Rockchip Inc.
+ * Author: Shawn Lin <shawn.lin@rock-chips.com>
+ *	   Chris Morgan <macroalpha82@gmail.com>
+ *	   Jon Lin <Jon.lin@rock-chips.com>
+ */
+
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/completion.h>
+#include <linux/dma-mapping.h>
+#include <linux/iopoll.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/spi/spi-mem.h>
+
+/* System control */
+#define SFC_CTRL			0x0
+#define  SFC_CTRL_PHASE_SEL_NEGETIVE	BIT(1)
+#define  SFC_CTRL_CMD_BITS_SHIFT	8
+#define  SFC_CTRL_ADDR_BITS_SHIFT	10
+#define  SFC_CTRL_DATA_BITS_SHIFT	12
+
+/* Interrupt mask */
+#define SFC_IMR				0x4
+#define  SFC_IMR_RX_FULL		BIT(0)
+#define  SFC_IMR_RX_UFLOW		BIT(1)
+#define  SFC_IMR_TX_OFLOW		BIT(2)
+#define  SFC_IMR_TX_EMPTY		BIT(3)
+#define  SFC_IMR_TRAN_FINISH		BIT(4)
+#define  SFC_IMR_BUS_ERR		BIT(5)
+#define  SFC_IMR_NSPI_ERR		BIT(6)
+#define  SFC_IMR_DMA			BIT(7)
+
+/* Interrupt clear */
+#define SFC_ICLR			0x8
+#define  SFC_ICLR_RX_FULL		BIT(0)
+#define  SFC_ICLR_RX_UFLOW		BIT(1)
+#define  SFC_ICLR_TX_OFLOW		BIT(2)
+#define  SFC_ICLR_TX_EMPTY		BIT(3)
+#define  SFC_ICLR_TRAN_FINISH		BIT(4)
+#define  SFC_ICLR_BUS_ERR		BIT(5)
+#define  SFC_ICLR_NSPI_ERR		BIT(6)
+#define  SFC_ICLR_DMA			BIT(7)
+
+/* FIFO threshold level */
+#define SFC_FTLR			0xc
+#define  SFC_FTLR_TX_SHIFT		0
+#define  SFC_FTLR_TX_MASK		0x1f
+#define  SFC_FTLR_RX_SHIFT		8
+#define  SFC_FTLR_RX_MASK		0x1f
+
+/* Reset FSM and FIFO */
+#define SFC_RCVR			0x10
+#define  SFC_RCVR_RESET			BIT(0)
+
+/* Enhanced mode */
+#define SFC_AX				0x14
+
+/* Address Bit number */
+#define SFC_ABIT			0x18
+
+/* Interrupt status */
+#define SFC_ISR				0x1c
+#define  SFC_ISR_RX_FULL_SHIFT		BIT(0)
+#define  SFC_ISR_RX_UFLOW_SHIFT		BIT(1)
+#define  SFC_ISR_TX_OFLOW_SHIFT		BIT(2)
+#define  SFC_ISR_TX_EMPTY_SHIFT		BIT(3)
+#define  SFC_ISR_TX_FINISH_SHIFT	BIT(4)
+#define  SFC_ISR_BUS_ERR_SHIFT		BIT(5)
+#define  SFC_ISR_NSPI_ERR_SHIFT		BIT(6)
+#define  SFC_ISR_DMA_SHIFT		BIT(7)
+
+/* FIFO status */
+#define SFC_FSR				0x20
+#define  SFC_FSR_TX_IS_FULL		BIT(0)
+#define  SFC_FSR_TX_IS_EMPTY		BIT(1)
+#define  SFC_FSR_RX_IS_EMPTY		BIT(2)
+#define  SFC_FSR_RX_IS_FULL		BIT(3)
+#define  SFC_FSR_TXLV_MASK		GENMASK(12, 8)
+#define  SFC_FSR_TXLV_SHIFT		8
+#define  SFC_FSR_RXLV_MASK		GENMASK(20, 16)
+#define  SFC_FSR_RXLV_SHIFT		16
+
+/* FSM status */
+#define SFC_SR				0x24
+#define  SFC_SR_IS_IDLE			0x0
+#define  SFC_SR_IS_BUSY			0x1
+
+/* Raw interrupt status */
+#define SFC_RISR			0x28
+#define  SFC_RISR_RX_FULL		BIT(0)
+#define  SFC_RISR_RX_UNDERFLOW		BIT(1)
+#define  SFC_RISR_TX_OVERFLOW		BIT(2)
+#define  SFC_RISR_TX_EMPTY		BIT(3)
+#define  SFC_RISR_TRAN_FINISH		BIT(4)
+#define  SFC_RISR_BUS_ERR		BIT(5)
+#define  SFC_RISR_NSPI_ERR		BIT(6)
+#define  SFC_RISR_DMA			BIT(7)
+
+/* Version */
+#define SFC_VER				0x2C
+#define  SFC_VER_3			0x3
+#define  SFC_VER_4			0x4
+#define  SFC_VER_5			0x5
+
+/* Master trigger */
+#define SFC_DMA_TRIGGER			0x80
+
+/* Src or Dst addr for master */
+#define SFC_DMA_ADDR			0x84
+
+/* Length control register extension 32GB */
+#define SFC_LEN_CTRL			0x88
+#define SFC_LEN_CTRL_TRB_SEL		1
+#define SFC_LEN_EXT			0x8C
+
+/* Command */
+#define SFC_CMD				0x100
+#define  SFC_CMD_IDX_SHIFT		0
+#define  SFC_CMD_DUMMY_SHIFT		8
+#define  SFC_CMD_DIR_SHIFT		12
+#define  SFC_CMD_DIR_RD			0
+#define  SFC_CMD_DIR_WR			1
+#define  SFC_CMD_ADDR_SHIFT		14
+#define  SFC_CMD_ADDR_0BITS		0
+#define  SFC_CMD_ADDR_24BITS		1
+#define  SFC_CMD_ADDR_32BITS		2
+#define  SFC_CMD_ADDR_XBITS		3
+#define  SFC_CMD_TRAN_BYTES_SHIFT	16
+#define  SFC_CMD_CS_SHIFT		30
+
+/* Address */
+#define SFC_ADDR			0x104
+
+/* Data */
+#define SFC_DATA			0x108
+
+/* The controller and documentation reports that it supports up to 4 CS
+ * devices (0-3), however I have only been able to test a single CS (CS 0)
+ * due to the configuration of my device.
+ */
+#define SFC_MAX_CHIPSELECT_NUM		4
+
+/* The SFC can transfer max 16KB - 1 at one time
+ * we set it to 15.5KB here for alignment.
+ */
+#define SFC_MAX_IOSIZE_VER3		(512 * 31)
+
+/* DMA is only enabled for large data transmission */
+#define SFC_DMA_TRANS_THRETHOLD		(0x40)
+
+/* Maximum clock values from datasheet suggest keeping clock value under
+ * 150MHz. No minimum or average value is suggested, but the U-boot BSP driver
+ * has a minimum of 10MHz and a default of 80MHz which seems reasonable.
+ */
+#define SFC_MIN_SPEED_HZ		(10 * 1000 * 1000)
+#define SFC_DEFAULT_SPEED_HZ		(80 * 1000 * 1000)
+#define SFC_MAX_SPEED_HZ		(150 * 1000 * 1000)
+
+struct rockchip_sfc {
+	struct device *dev;
+	void __iomem *regbase;
+	struct clk *hclk;
+	struct clk *clk;
+	u32 frequency;
+	/* virtual mapped addr for dma_buffer */
+	void *buffer;
+	dma_addr_t dma_buffer;
+	struct completion cp;
+	bool use_dma;
+	u32 max_iosize;
+	u16 version;
+};
+
+static int rockchip_sfc_reset(struct rockchip_sfc *sfc)
+{
+	int err;
+	u32 status;
+
+	writel_relaxed(SFC_RCVR_RESET, sfc->regbase + SFC_RCVR);
+
+	err = readl_poll_timeout(sfc->regbase + SFC_RCVR, status,
+				 !(status & SFC_RCVR_RESET), 20,
+				 jiffies_to_usecs(HZ));
+	if (err)
+		dev_err(sfc->dev, "SFC reset never finished\n");
+
+	/* Still need to clear the masked interrupt from RISR */
+	writel_relaxed(0xFFFFFFFF, sfc->regbase + SFC_ICLR);
+
+	dev_dbg(sfc->dev, "reset\n");
+
+	return err;
+}
+
+static u16 rockchip_sfc_get_version(struct rockchip_sfc *sfc)
+{
+	return  (u16)(readl(sfc->regbase + SFC_VER) & 0xffff);
+}
+
+static u32 rockchip_sfc_get_max_iosize(struct rockchip_sfc *sfc)
+{
+	return SFC_MAX_IOSIZE_VER3;
+}
+
+static void rockchip_sfc_irq_unmask(struct rockchip_sfc *sfc, u32 mask)
+{
+	u32 reg;
+
+	/* Enable transfer complete interrupt */
+	reg = readl(sfc->regbase + SFC_IMR);
+	reg &= ~mask;
+	writel(reg, sfc->regbase + SFC_IMR);
+}
+
+static void rockchip_sfc_irq_mask(struct rockchip_sfc *sfc, u32 mask)
+{
+	u32 reg;
+
+	/* Disable transfer finish interrupt */
+	reg = readl(sfc->regbase + SFC_IMR);
+	reg |= mask;
+	writel(reg, sfc->regbase + SFC_IMR);
+}
+
+static int rockchip_sfc_init(struct rockchip_sfc *sfc)
+{
+	writel(0, sfc->regbase + SFC_CTRL);
+	if (rockchip_sfc_get_version(sfc) >= SFC_VER_4)
+		writel(SFC_LEN_CTRL_TRB_SEL, sfc->regbase + SFC_LEN_CTRL);
+
+	return 0;
+}
+
+static inline int rockchip_sfc_get_fifo_level(struct rockchip_sfc *sfc, int wr)
+{
+	u32 fsr = readl_relaxed(sfc->regbase + SFC_FSR);
+	int level;
+
+	if (wr)
+		level = (fsr & SFC_FSR_TXLV_MASK) >> SFC_FSR_TXLV_SHIFT;
+	else
+		level = (fsr & SFC_FSR_RXLV_MASK) >> SFC_FSR_RXLV_SHIFT;
+
+	return level;
+}
+
+static int rockchip_sfc_wait_fifo_ready(struct rockchip_sfc *sfc, int wr, u32 timeout)
+{
+	unsigned long deadline = jiffies + timeout;
+	int level;
+
+	while (!(level = rockchip_sfc_get_fifo_level(sfc, wr))) {
+		if (time_after_eq(jiffies, deadline)) {
+			dev_warn(sfc->dev, "%s fifo timeout\n", wr ? "write" : "read");
+			return -ETIMEDOUT;
+		}
+		udelay(1);
+	}
+
+	return level;
+}
+
+static void rockchip_sfc_adjust_op_work(struct spi_mem_op *op)
+{
+	if (unlikely(op->dummy.nbytes && !op->addr.nbytes)) {
+		/*
+		 * SFC not support output DUMMY cycles right after CMD cycles, so
+		 * treat it as ADDR cycles.
+		 */
+		op->addr.nbytes = op->dummy.nbytes;
+		op->addr.buswidth = op->dummy.buswidth;
+		op->addr.val = 0xFFFFFFFFF;
+
+		op->dummy.nbytes = 0;
+	}
+}
+
+static int rockchip_sfc_xfer_setup(struct rockchip_sfc *sfc,
+				   struct spi_mem *mem,
+				   const struct spi_mem_op *op,
+				   u32 len)
+{
+	u32 ctrl = 0, cmd = 0;
+
+	/* set CMD */
+	cmd = op->cmd.opcode;
+	ctrl |= ((op->cmd.buswidth >> 1) << SFC_CTRL_CMD_BITS_SHIFT);
+
+	/* set ADDR */
+	if (op->addr.nbytes) {
+		if (op->addr.nbytes == 4) {
+			cmd |= SFC_CMD_ADDR_32BITS << SFC_CMD_ADDR_SHIFT;
+		} else if (op->addr.nbytes == 3) {
+			cmd |= SFC_CMD_ADDR_24BITS << SFC_CMD_ADDR_SHIFT;
+		} else {
+			cmd |= SFC_CMD_ADDR_XBITS << SFC_CMD_ADDR_SHIFT;
+			writel_relaxed(op->addr.nbytes * 8 - 1, sfc->regbase + SFC_ABIT);
+		}
+
+		ctrl |= ((op->addr.buswidth >> 1) << SFC_CTRL_ADDR_BITS_SHIFT);
+	}
+
+	/* set DUMMY */
+	if (op->dummy.nbytes) {
+		if (op->dummy.buswidth == 4)
+			cmd |= op->dummy.nbytes * 2 << SFC_CMD_DUMMY_SHIFT;
+		else if (op->dummy.buswidth == 2)
+			cmd |= op->dummy.nbytes * 4 << SFC_CMD_DUMMY_SHIFT;
+		else
+			cmd |= op->dummy.nbytes * 8 << SFC_CMD_DUMMY_SHIFT;
+	}
+
+	/* set DATA */
+	if (sfc->version >= SFC_VER_4) /* Clear it if no data to transfer */
+		writel(len, sfc->regbase + SFC_LEN_EXT);
+	else
+		cmd |= len << SFC_CMD_TRAN_BYTES_SHIFT;
+	if (len) {
+		if (op->data.dir == SPI_MEM_DATA_OUT)
+			cmd |= SFC_CMD_DIR_WR << SFC_CMD_DIR_SHIFT;
+
+		ctrl |= ((op->data.buswidth >> 1) << SFC_CTRL_DATA_BITS_SHIFT);
+	}
+	if (!len && op->addr.nbytes)
+		cmd |= SFC_CMD_DIR_WR << SFC_CMD_DIR_SHIFT;
+
+	/* set the Controller */
+	ctrl |= SFC_CTRL_PHASE_SEL_NEGETIVE;
+	cmd |= mem->spi->chip_select << SFC_CMD_CS_SHIFT;
+
+	dev_dbg(sfc->dev, "addr.nbytes=%x(x%d) dummy.nbytes=%x(x%d)\n",
+		op->addr.nbytes, op->addr.buswidth,
+		op->dummy.nbytes, op->dummy.buswidth);
+	dev_dbg(sfc->dev, "ctrl=%x cmd=%x addr=%llx len=%x\n",
+		ctrl, cmd, op->addr.val, len);
+
+	writel(ctrl, sfc->regbase + SFC_CTRL);
+	writel(cmd, sfc->regbase + SFC_CMD);
+	if (op->addr.nbytes)
+		writel(op->addr.val, sfc->regbase + SFC_ADDR);
+
+	return 0;
+}
+
+static int rockchip_sfc_write_fifo(struct rockchip_sfc *sfc, const u8 *buf, int len)
+{
+	u8 bytes = len & 0x3;
+	u32 dwords;
+	int tx_level;
+	u32 write_words;
+	u32 tmp = 0;
+
+	dwords = len >> 2;
+	while (dwords) {
+		tx_level = rockchip_sfc_wait_fifo_ready(sfc, SFC_CMD_DIR_WR, HZ);
+		if (tx_level < 0)
+			return tx_level;
+		write_words = min_t(u32, tx_level, dwords);
+		iowrite32_rep(sfc->regbase + SFC_DATA, buf, write_words);
+		buf += write_words << 2;
+		dwords -= write_words;
+	}
+
+	/* write the rest non word aligned bytes */
+	if (bytes) {
+		tx_level = rockchip_sfc_wait_fifo_ready(sfc, SFC_CMD_DIR_WR, HZ);
+		if (tx_level < 0)
+			return tx_level;
+		memcpy(&tmp, buf, bytes);
+		writel(tmp, sfc->regbase + SFC_DATA);
+	}
+
+	return len;
+}
+
+static int rockchip_sfc_read_fifo(struct rockchip_sfc *sfc, u8 *buf, int len)
+{
+	u8 bytes = len & 0x3;
+	u32 dwords;
+	u8 read_words;
+	int rx_level;
+	int tmp;
+
+	/* word aligned access only */
+	dwords = len >> 2;
+	while (dwords) {
+		rx_level = rockchip_sfc_wait_fifo_ready(sfc, SFC_CMD_DIR_RD, HZ);
+		if (rx_level < 0)
+			return rx_level;
+		read_words = min_t(u32, rx_level, dwords);
+		ioread32_rep(sfc->regbase + SFC_DATA, buf, read_words);
+		buf += read_words << 2;
+		dwords -= read_words;
+	}
+
+	/* read the rest non word aligned bytes */
+	if (bytes) {
+		rx_level = rockchip_sfc_wait_fifo_ready(sfc, SFC_CMD_DIR_RD, HZ);
+		if (rx_level < 0)
+			return rx_level;
+		tmp = readl_relaxed(sfc->regbase + SFC_DATA);
+		memcpy(buf, &tmp, bytes);
+	}
+
+	return len;
+}
+
+static int rockchip_sfc_fifo_transfer_dma(struct rockchip_sfc *sfc, dma_addr_t dma_buf, size_t len)
+{
+	writel(0xFFFFFFFF, sfc->regbase + SFC_ICLR);
+	writel((u32)dma_buf, sfc->regbase + SFC_DMA_ADDR);
+	writel(0x1, sfc->regbase + SFC_DMA_TRIGGER);
+
+	return len;
+}
+
+static int rockchip_sfc_xfer_data_poll(struct rockchip_sfc *sfc,
+				       const struct spi_mem_op *op, u32 len)
+{
+	dev_dbg(sfc->dev, "xfer_poll len=%x\n", len);
+
+	if (op->data.dir == SPI_MEM_DATA_OUT)
+		return rockchip_sfc_write_fifo(sfc, op->data.buf.out, len);
+	else
+		return rockchip_sfc_read_fifo(sfc, op->data.buf.in, len);
+}
+
+static int rockchip_sfc_xfer_data_dma(struct rockchip_sfc *sfc,
+				      const struct spi_mem_op *op, u32 len)
+{
+	int ret;
+
+	dev_dbg(sfc->dev, "xfer_dma len=%x\n", len);
+
+	if (op->data.dir == SPI_MEM_DATA_OUT)
+		memcpy_toio(sfc->buffer, op->data.buf.out, len);
+
+	ret = rockchip_sfc_fifo_transfer_dma(sfc, sfc->dma_buffer, len);
+	if (!wait_for_completion_timeout(&sfc->cp, msecs_to_jiffies(2000))) {
+		dev_err(sfc->dev, "DMA wait for transfer finish timeout\n");
+		ret = -ETIMEDOUT;
+	}
+	rockchip_sfc_irq_mask(sfc, SFC_IMR_DMA);
+	if (op->data.dir == SPI_MEM_DATA_IN)
+		memcpy_fromio(op->data.buf.in, sfc->buffer, len);
+
+	return ret;
+}
+
+static int rockchip_sfc_xfer_done(struct rockchip_sfc *sfc, u32 timeout_us)
+{
+	int ret = 0;
+	u32 status;
+
+	ret = readl_poll_timeout(sfc->regbase + SFC_SR, status,
+				 !(status & SFC_SR_IS_BUSY),
+				 20, timeout_us);
+	if (ret) {
+		dev_err(sfc->dev, "wait sfc idle timeout\n");
+		rockchip_sfc_reset(sfc);
+
+		ret = -EIO;
+	}
+
+	return ret;
+}
+
+static int rockchip_sfc_exec_mem_op(struct spi_mem *mem, const struct spi_mem_op *op)
+{
+	struct rockchip_sfc *sfc = spi_master_get_devdata(mem->spi->master);
+	u32 len = op->data.nbytes;
+	int ret;
+
+	if (unlikely(mem->spi->max_speed_hz != sfc->frequency)) {
+		ret = clk_set_rate(sfc->clk, mem->spi->max_speed_hz);
+		if (ret)
+			return ret;
+		sfc->frequency = mem->spi->max_speed_hz;
+		dev_dbg(sfc->dev, "set_freq=%dHz real_freq=%ldHz\n",
+			sfc->frequency, clk_get_rate(sfc->clk));
+	}
+
+	rockchip_sfc_adjust_op_work((struct spi_mem_op *)op);
+
+	rockchip_sfc_xfer_setup(sfc, mem, op, len);
+	if (len) {
+		if (likely(sfc->use_dma) && !(len & 0x3) && len >= SFC_DMA_TRANS_THRETHOLD) {
+			init_completion(&sfc->cp);
+			rockchip_sfc_irq_unmask(sfc, SFC_IMR_DMA);
+			ret = rockchip_sfc_xfer_data_dma(sfc, op, len);
+		} else {
+			ret = rockchip_sfc_xfer_data_poll(sfc, op, len);
+		}
+
+		if (ret != len) {
+			dev_err(sfc->dev, "xfer data failed ret %d dir %d\n", ret, op->data.dir);
+
+			return -EIO;
+		}
+	}
+
+	return rockchip_sfc_xfer_done(sfc, 100000);
+}
+
+static int rockchip_sfc_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
+{
+	struct rockchip_sfc *sfc = spi_master_get_devdata(mem->spi->master);
+
+	op->data.nbytes = min(op->data.nbytes, sfc->max_iosize);
+
+	return 0;
+}
+
+static const struct spi_controller_mem_ops rockchip_sfc_mem_ops = {
+	.exec_op = rockchip_sfc_exec_mem_op,
+	.adjust_op_size = rockchip_sfc_adjust_op_size,
+};
+
+static irqreturn_t rockchip_sfc_irq_handler(int irq, void *dev_id)
+{
+	struct rockchip_sfc *sfc = dev_id;
+	u32 reg;
+
+	reg = readl(sfc->regbase + SFC_RISR);
+
+	/* Clear interrupt */
+	writel_relaxed(reg, sfc->regbase + SFC_ICLR);
+
+	if (reg & SFC_RISR_DMA)
+		complete(&sfc->cp);
+
+	return IRQ_HANDLED;
+}
+
+static int rockchip_sfc_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct spi_master *master;
+	struct resource *res;
+	struct rockchip_sfc *sfc;
+	int ret;
+
+	master = devm_spi_alloc_master(&pdev->dev, sizeof(*sfc));
+	if (!master)
+		return -ENOMEM;
+
+	master->mem_ops = &rockchip_sfc_mem_ops;
+	master->dev.of_node = pdev->dev.of_node;
+	master->mode_bits = SPI_TX_QUAD | SPI_TX_DUAL | SPI_RX_QUAD | SPI_RX_DUAL;
+	master->min_speed_hz = SFC_MIN_SPEED_HZ;
+	master->max_speed_hz = SFC_MAX_SPEED_HZ;
+	master->num_chipselect = SFC_MAX_CHIPSELECT_NUM;
+
+	sfc = spi_master_get_devdata(master);
+	sfc->dev = dev;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	sfc->regbase = devm_ioremap_resource(dev, res);
+	if (IS_ERR(sfc->regbase))
+		return PTR_ERR(sfc->regbase);
+
+	sfc->clk = devm_clk_get(&pdev->dev, "clk_sfc");
+	if (IS_ERR(sfc->clk)) {
+		dev_err(&pdev->dev, "Failed to get sfc interface clk\n");
+		return PTR_ERR(sfc->clk);
+	}
+
+	sfc->hclk = devm_clk_get(&pdev->dev, "hclk_sfc");
+	if (IS_ERR(sfc->hclk)) {
+		dev_err(&pdev->dev, "Failed to get sfc ahb clk\n");
+		return PTR_ERR(sfc->hclk);
+	}
+
+	sfc->use_dma = !of_property_read_bool(sfc->dev->of_node,
+					      "rockchip,sfc-no-dma");
+
+	if (sfc->use_dma) {
+		ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
+		if (ret) {
+			dev_warn(dev, "Unable to set dma mask\n");
+			return ret;
+		}
+
+		sfc->buffer = dmam_alloc_coherent(dev, SFC_MAX_IOSIZE_VER3,
+						  &sfc->dma_buffer,
+						  GFP_KERNEL);
+		if (!sfc->buffer)
+			return -ENOMEM;
+	}
+
+	ret = clk_prepare_enable(sfc->hclk);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to enable ahb clk\n");
+		goto err_hclk;
+	}
+
+	ret = clk_prepare_enable(sfc->clk);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to enable interface clk\n");
+		goto err_clk;
+	}
+
+	/* Find the irq */
+	ret = platform_get_irq(pdev, 0);
+	if (ret < 0) {
+		dev_err(dev, "Failed to get the irq\n");
+		goto err_irq;
+	}
+
+	ret = devm_request_irq(dev, ret, rockchip_sfc_irq_handler,
+			       0, pdev->name, sfc);
+	if (ret) {
+		dev_err(dev, "Failed to request irq\n");
+
+		return ret;
+	}
+
+	ret = rockchip_sfc_init(sfc);
+	if (ret)
+		goto err_irq;
+
+	sfc->max_iosize = rockchip_sfc_get_max_iosize(sfc);
+	sfc->version = rockchip_sfc_get_version(sfc);
+
+	ret = spi_register_master(master);
+	if (ret)
+		goto err_irq;
+
+	return 0;
+
+err_irq:
+	clk_disable_unprepare(sfc->clk);
+err_clk:
+	clk_disable_unprepare(sfc->hclk);
+err_hclk:
+	return ret;
+}
+
+static int rockchip_sfc_remove(struct platform_device *pdev)
+{
+	struct spi_master *master = platform_get_drvdata(pdev);
+	struct rockchip_sfc *sfc = platform_get_drvdata(pdev);
+
+	spi_unregister_master(master);
+
+	clk_disable_unprepare(sfc->clk);
+	clk_disable_unprepare(sfc->hclk);
+
+	return 0;
+}
+
+static const struct of_device_id rockchip_sfc_dt_ids[] = {
+	{ .compatible = "rockchip,sfc"},
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, rockchip_sfc_dt_ids);
+
+static struct platform_driver rockchip_sfc_driver = {
+	.driver = {
+		.name	= "rockchip-sfc",
+		.of_match_table = rockchip_sfc_dt_ids,
+	},
+	.probe	= rockchip_sfc_probe,
+	.remove	= rockchip_sfc_remove,
+};
+module_platform_driver(rockchip_sfc_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Rockchip Serial Flash Controller Driver");
+MODULE_AUTHOR("Shawn Lin <shawn.lin@rock-chips.com>");
+MODULE_AUTHOR("Chris Morgan <macromorgan@hotmail.com>");
+MODULE_AUTHOR("Jon Lin <Jon.lin@rock-chips.com>");
-- 
2.17.1