mtd: spi-nor: Add driver for Cadence Quad SPI Flash Controller
authorGraham Moore <grmoore@opensource.altera.com>
Sat, 4 Jun 2016 00:39:34 +0000 (02:39 +0200)
committerBrian Norris <computersforpeace@gmail.com>
Mon, 18 Jul 2016 17:00:23 +0000 (10:00 -0700)
Add support for the Cadence QSPI controller. This controller is
present in the Altera SoCFPGA SoCs and this driver has been tested
on the Cyclone V SoC.

Signed-off-by: Graham Moore <grmoore@opensource.altera.com>
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Alan Tull <atull@opensource.altera.com>
Cc: Brian Norris <computersforpeace@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Dinh Nguyen <dinguyen@opensource.altera.com>
Cc: Graham Moore <grmoore@opensource.altera.com>
Cc: Vignesh R <vigneshr@ti.com>
Cc: Yves Vandervennet <yvanderv@opensource.altera.com>
Cc: devicetree@vger.kernel.org
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
drivers/mtd/spi-nor/Kconfig
drivers/mtd/spi-nor/Makefile
drivers/mtd/spi-nor/cadence-quadspi.c [new file with mode: 0644]

index 93a0145ef17c8d5a64b55e1826df0f0cbb5143d0..1e6f037923d9a1845bac17c230fca793e24f64f9 100644 (file)
@@ -38,6 +38,17 @@ config SPI_ATMEL_QUADSPI
          This driver does not support generic SPI. The implementation only
          supports SPI NOR.
 
+config SPI_CADENCE_QUADSPI
+       tristate "Cadence Quad SPI controller"
+       depends on OF && (ARM || COMPILE_TEST)
+       help
+         Enable support for the Cadence Quad SPI Flash controller.
+
+         Cadence QSPI is a specialized controller for connecting an SPI
+         Flash over 1/2/4-bit wide bus. Enable this option if you have a
+         device with a Cadence QSPI controller and want to access the
+         Flash as an MTD device.
+
 config SPI_FSL_QUADSPI
        tristate "Freescale Quad SPI controller"
        depends on ARCH_MXC || SOC_LS1021A || ARCH_LAYERSCAPE || COMPILE_TEST
index 896d32695d96f4f4cfc44ee1dd1dac6bf75bf6e2..121695e83542ab80593042254aa73e81d5456d45 100644 (file)
@@ -1,5 +1,6 @@
 obj-$(CONFIG_MTD_SPI_NOR)      += spi-nor.o
 obj-$(CONFIG_SPI_ATMEL_QUADSPI)        += atmel-quadspi.o
+obj-$(CONFIG_SPI_CADENCE_QUADSPI)      += cadence-quadspi.o
 obj-$(CONFIG_SPI_FSL_QUADSPI)  += fsl-quadspi.o
 obj-$(CONFIG_SPI_HISI_SFC)     += hisi-sfc.o
 obj-$(CONFIG_MTD_MT81xx_NOR)    += mtk-quadspi.o
diff --git a/drivers/mtd/spi-nor/cadence-quadspi.c b/drivers/mtd/spi-nor/cadence-quadspi.c
new file mode 100644 (file)
index 0000000..d403ba7
--- /dev/null
@@ -0,0 +1,1299 @@
+/*
+ * Driver for Cadence QSPI Controller
+ *
+ * Copyright Altera Corporation (C) 2012-2014. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#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/mtd/mtd.h>
+#include <linux/mtd/partitions.h>
+#include <linux/mtd/spi-nor.h>
+#include <linux/of_device.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/sched.h>
+#include <linux/spi/spi.h>
+#include <linux/timer.h>
+
+#define CQSPI_NAME                     "cadence-qspi"
+#define CQSPI_MAX_CHIPSELECT           16
+
+struct cqspi_st;
+
+struct cqspi_flash_pdata {
+       struct spi_nor  nor;
+       struct cqspi_st *cqspi;
+       u32             clk_rate;
+       u32             read_delay;
+       u32             tshsl_ns;
+       u32             tsd2d_ns;
+       u32             tchsh_ns;
+       u32             tslch_ns;
+       u8              inst_width;
+       u8              addr_width;
+       u8              data_width;
+       u8              cs;
+       bool            registered;
+};
+
+struct cqspi_st {
+       struct platform_device  *pdev;
+
+       struct clk              *clk;
+       unsigned int            sclk;
+
+       void __iomem            *iobase;
+       void __iomem            *ahb_base;
+       struct completion       transfer_complete;
+       struct mutex            bus_mutex;
+
+       int                     current_cs;
+       int                     current_page_size;
+       int                     current_erase_size;
+       int                     current_addr_width;
+       unsigned long           master_ref_clk_hz;
+       bool                    is_decoded_cs;
+       u32                     fifo_depth;
+       u32                     fifo_width;
+       u32                     trigger_address;
+       struct cqspi_flash_pdata f_pdata[CQSPI_MAX_CHIPSELECT];
+};
+
+/* Operation timeout value */
+#define CQSPI_TIMEOUT_MS                       500
+#define CQSPI_READ_TIMEOUT_MS                  10
+
+/* Instruction type */
+#define CQSPI_INST_TYPE_SINGLE                 0
+#define CQSPI_INST_TYPE_DUAL                   1
+#define CQSPI_INST_TYPE_QUAD                   2
+
+#define CQSPI_DUMMY_CLKS_PER_BYTE              8
+#define CQSPI_DUMMY_BYTES_MAX                  4
+#define CQSPI_DUMMY_CLKS_MAX                   31
+
+#define CQSPI_STIG_DATA_LEN_MAX                        8
+
+/* Register map */
+#define CQSPI_REG_CONFIG                       0x00
+#define CQSPI_REG_CONFIG_ENABLE_MASK           BIT(0)
+#define CQSPI_REG_CONFIG_DECODE_MASK           BIT(9)
+#define CQSPI_REG_CONFIG_CHIPSELECT_LSB                10
+#define CQSPI_REG_CONFIG_DMA_MASK              BIT(15)
+#define CQSPI_REG_CONFIG_BAUD_LSB              19
+#define CQSPI_REG_CONFIG_IDLE_LSB              31
+#define CQSPI_REG_CONFIG_CHIPSELECT_MASK       0xF
+#define CQSPI_REG_CONFIG_BAUD_MASK             0xF
+
+#define CQSPI_REG_RD_INSTR                     0x04
+#define CQSPI_REG_RD_INSTR_OPCODE_LSB          0
+#define CQSPI_REG_RD_INSTR_TYPE_INSTR_LSB      8
+#define CQSPI_REG_RD_INSTR_TYPE_ADDR_LSB       12
+#define CQSPI_REG_RD_INSTR_TYPE_DATA_LSB       16
+#define CQSPI_REG_RD_INSTR_MODE_EN_LSB         20
+#define CQSPI_REG_RD_INSTR_DUMMY_LSB           24
+#define CQSPI_REG_RD_INSTR_TYPE_INSTR_MASK     0x3
+#define CQSPI_REG_RD_INSTR_TYPE_ADDR_MASK      0x3
+#define CQSPI_REG_RD_INSTR_TYPE_DATA_MASK      0x3
+#define CQSPI_REG_RD_INSTR_DUMMY_MASK          0x1F
+
+#define CQSPI_REG_WR_INSTR                     0x08
+#define CQSPI_REG_WR_INSTR_OPCODE_LSB          0
+#define CQSPI_REG_WR_INSTR_TYPE_ADDR_LSB       12
+#define CQSPI_REG_WR_INSTR_TYPE_DATA_LSB       16
+
+#define CQSPI_REG_DELAY                                0x0C
+#define CQSPI_REG_DELAY_TSLCH_LSB              0
+#define CQSPI_REG_DELAY_TCHSH_LSB              8
+#define CQSPI_REG_DELAY_TSD2D_LSB              16
+#define CQSPI_REG_DELAY_TSHSL_LSB              24
+#define CQSPI_REG_DELAY_TSLCH_MASK             0xFF
+#define CQSPI_REG_DELAY_TCHSH_MASK             0xFF
+#define CQSPI_REG_DELAY_TSD2D_MASK             0xFF
+#define CQSPI_REG_DELAY_TSHSL_MASK             0xFF
+
+#define CQSPI_REG_READCAPTURE                  0x10
+#define CQSPI_REG_READCAPTURE_BYPASS_LSB       0
+#define CQSPI_REG_READCAPTURE_DELAY_LSB                1
+#define CQSPI_REG_READCAPTURE_DELAY_MASK       0xF
+
+#define CQSPI_REG_SIZE                         0x14
+#define CQSPI_REG_SIZE_ADDRESS_LSB             0
+#define CQSPI_REG_SIZE_PAGE_LSB                        4
+#define CQSPI_REG_SIZE_BLOCK_LSB               16
+#define CQSPI_REG_SIZE_ADDRESS_MASK            0xF
+#define CQSPI_REG_SIZE_PAGE_MASK               0xFFF
+#define CQSPI_REG_SIZE_BLOCK_MASK              0x3F
+
+#define CQSPI_REG_SRAMPARTITION                        0x18
+#define CQSPI_REG_INDIRECTTRIGGER              0x1C
+
+#define CQSPI_REG_DMA                          0x20
+#define CQSPI_REG_DMA_SINGLE_LSB               0
+#define CQSPI_REG_DMA_BURST_LSB                        8
+#define CQSPI_REG_DMA_SINGLE_MASK              0xFF
+#define CQSPI_REG_DMA_BURST_MASK               0xFF
+
+#define CQSPI_REG_REMAP                                0x24
+#define CQSPI_REG_MODE_BIT                     0x28
+
+#define CQSPI_REG_SDRAMLEVEL                   0x2C
+#define CQSPI_REG_SDRAMLEVEL_RD_LSB            0
+#define CQSPI_REG_SDRAMLEVEL_WR_LSB            16
+#define CQSPI_REG_SDRAMLEVEL_RD_MASK           0xFFFF
+#define CQSPI_REG_SDRAMLEVEL_WR_MASK           0xFFFF
+
+#define CQSPI_REG_IRQSTATUS                    0x40
+#define CQSPI_REG_IRQMASK                      0x44
+
+#define CQSPI_REG_INDIRECTRD                   0x60
+#define CQSPI_REG_INDIRECTRD_START_MASK                BIT(0)
+#define CQSPI_REG_INDIRECTRD_CANCEL_MASK       BIT(1)
+#define CQSPI_REG_INDIRECTRD_DONE_MASK         BIT(5)
+
+#define CQSPI_REG_INDIRECTRDWATERMARK          0x64
+#define CQSPI_REG_INDIRECTRDSTARTADDR          0x68
+#define CQSPI_REG_INDIRECTRDBYTES              0x6C
+
+#define CQSPI_REG_CMDCTRL                      0x90
+#define CQSPI_REG_CMDCTRL_EXECUTE_MASK         BIT(0)
+#define CQSPI_REG_CMDCTRL_INPROGRESS_MASK      BIT(1)
+#define CQSPI_REG_CMDCTRL_WR_BYTES_LSB         12
+#define CQSPI_REG_CMDCTRL_WR_EN_LSB            15
+#define CQSPI_REG_CMDCTRL_ADD_BYTES_LSB                16
+#define CQSPI_REG_CMDCTRL_ADDR_EN_LSB          19
+#define CQSPI_REG_CMDCTRL_RD_BYTES_LSB         20
+#define CQSPI_REG_CMDCTRL_RD_EN_LSB            23
+#define CQSPI_REG_CMDCTRL_OPCODE_LSB           24
+#define CQSPI_REG_CMDCTRL_WR_BYTES_MASK                0x7
+#define CQSPI_REG_CMDCTRL_ADD_BYTES_MASK       0x3
+#define CQSPI_REG_CMDCTRL_RD_BYTES_MASK                0x7
+
+#define CQSPI_REG_INDIRECTWR                   0x70
+#define CQSPI_REG_INDIRECTWR_START_MASK                BIT(0)
+#define CQSPI_REG_INDIRECTWR_CANCEL_MASK       BIT(1)
+#define CQSPI_REG_INDIRECTWR_DONE_MASK         BIT(5)
+
+#define CQSPI_REG_INDIRECTWRWATERMARK          0x74
+#define CQSPI_REG_INDIRECTWRSTARTADDR          0x78
+#define CQSPI_REG_INDIRECTWRBYTES              0x7C
+
+#define CQSPI_REG_CMDADDRESS                   0x94
+#define CQSPI_REG_CMDREADDATALOWER             0xA0
+#define CQSPI_REG_CMDREADDATAUPPER             0xA4
+#define CQSPI_REG_CMDWRITEDATALOWER            0xA8
+#define CQSPI_REG_CMDWRITEDATAUPPER            0xAC
+
+/* Interrupt status bits */
+#define CQSPI_REG_IRQ_MODE_ERR                 BIT(0)
+#define CQSPI_REG_IRQ_UNDERFLOW                        BIT(1)
+#define CQSPI_REG_IRQ_IND_COMP                 BIT(2)
+#define CQSPI_REG_IRQ_IND_RD_REJECT            BIT(3)
+#define CQSPI_REG_IRQ_WR_PROTECTED_ERR         BIT(4)
+#define CQSPI_REG_IRQ_ILLEGAL_AHB_ERR          BIT(5)
+#define CQSPI_REG_IRQ_WATERMARK                        BIT(6)
+#define CQSPI_REG_IRQ_IND_SRAM_FULL            BIT(12)
+
+#define CQSPI_IRQ_MASK_RD              (CQSPI_REG_IRQ_WATERMARK        | \
+                                        CQSPI_REG_IRQ_IND_SRAM_FULL    | \
+                                        CQSPI_REG_IRQ_IND_COMP)
+
+#define CQSPI_IRQ_MASK_WR              (CQSPI_REG_IRQ_IND_COMP         | \
+                                        CQSPI_REG_IRQ_WATERMARK        | \
+                                        CQSPI_REG_IRQ_UNDERFLOW)
+
+#define CQSPI_IRQ_STATUS_MASK          0x1FFFF
+
+static int cqspi_wait_for_bit(void __iomem *reg, const u32 mask, bool clear)
+{
+       unsigned long end = jiffies + msecs_to_jiffies(CQSPI_TIMEOUT_MS);
+       u32 val;
+
+       while (1) {
+               val = readl(reg);
+               if (clear)
+                       val = ~val;
+               val &= mask;
+
+               if (val == mask)
+                       return 0;
+
+               if (time_after(jiffies, end))
+                       return -ETIMEDOUT;
+       }
+}
+
+static bool cqspi_is_idle(struct cqspi_st *cqspi)
+{
+       u32 reg = readl(cqspi->iobase + CQSPI_REG_CONFIG);
+
+       return reg & (1 << CQSPI_REG_CONFIG_IDLE_LSB);
+}
+
+static u32 cqspi_get_rd_sram_level(struct cqspi_st *cqspi)
+{
+       u32 reg = readl(cqspi->iobase + CQSPI_REG_SDRAMLEVEL);
+
+       reg >>= CQSPI_REG_SDRAMLEVEL_RD_LSB;
+       return reg & CQSPI_REG_SDRAMLEVEL_RD_MASK;
+}
+
+static irqreturn_t cqspi_irq_handler(int this_irq, void *dev)
+{
+       struct cqspi_st *cqspi = dev;
+       unsigned int irq_status;
+
+       /* Read interrupt status */
+       irq_status = readl(cqspi->iobase + CQSPI_REG_IRQSTATUS);
+
+       /* Clear interrupt */
+       writel(irq_status, cqspi->iobase + CQSPI_REG_IRQSTATUS);
+
+       irq_status &= CQSPI_IRQ_MASK_RD | CQSPI_IRQ_MASK_WR;
+
+       if (irq_status)
+               complete(&cqspi->transfer_complete);
+
+       return IRQ_HANDLED;
+}
+
+static unsigned int cqspi_calc_rdreg(struct spi_nor *nor, const u8 opcode)
+{
+       struct cqspi_flash_pdata *f_pdata = nor->priv;
+       u32 rdreg = 0;
+
+       rdreg |= f_pdata->inst_width << CQSPI_REG_RD_INSTR_TYPE_INSTR_LSB;
+       rdreg |= f_pdata->addr_width << CQSPI_REG_RD_INSTR_TYPE_ADDR_LSB;
+       rdreg |= f_pdata->data_width << CQSPI_REG_RD_INSTR_TYPE_DATA_LSB;
+
+       return rdreg;
+}
+
+static int cqspi_wait_idle(struct cqspi_st *cqspi)
+{
+       const unsigned int poll_idle_retry = 3;
+       unsigned int count = 0;
+       unsigned long timeout;
+
+       timeout = jiffies + msecs_to_jiffies(CQSPI_TIMEOUT_MS);
+       while (1) {
+               /*
+                * Read few times in succession to ensure the controller
+                * is indeed idle, that is, the bit does not transition
+                * low again.
+                */
+               if (cqspi_is_idle(cqspi))
+                       count++;
+               else
+                       count = 0;
+
+               if (count >= poll_idle_retry)
+                       return 0;
+
+               if (time_after(jiffies, timeout)) {
+                       /* Timeout, in busy mode. */
+                       dev_err(&cqspi->pdev->dev,
+                               "QSPI is still busy after %dms timeout.\n",
+                               CQSPI_TIMEOUT_MS);
+                       return -ETIMEDOUT;
+               }
+
+               cpu_relax();
+       }
+}
+
+static int cqspi_exec_flash_cmd(struct cqspi_st *cqspi, unsigned int reg)
+{
+       void __iomem *reg_base = cqspi->iobase;
+       int ret;
+
+       /* Write the CMDCTRL without start execution. */
+       writel(reg, reg_base + CQSPI_REG_CMDCTRL);
+       /* Start execute */
+       reg |= CQSPI_REG_CMDCTRL_EXECUTE_MASK;
+       writel(reg, reg_base + CQSPI_REG_CMDCTRL);
+
+       /* Polling for completion. */
+       ret = cqspi_wait_for_bit(reg_base + CQSPI_REG_CMDCTRL,
+                                CQSPI_REG_CMDCTRL_INPROGRESS_MASK, 1);
+       if (ret) {
+               dev_err(&cqspi->pdev->dev,
+                       "Flash command execution timed out.\n");
+               return ret;
+       }
+
+       /* Polling QSPI idle status. */
+       return cqspi_wait_idle(cqspi);
+}
+
+static int cqspi_command_read(struct spi_nor *nor,
+                             const u8 *txbuf, const unsigned n_tx,
+                             u8 *rxbuf, const unsigned n_rx)
+{
+       struct cqspi_flash_pdata *f_pdata = nor->priv;
+       struct cqspi_st *cqspi = f_pdata->cqspi;
+       void __iomem *reg_base = cqspi->iobase;
+       unsigned int rdreg;
+       unsigned int reg;
+       unsigned int read_len;
+       int status;
+
+       if (!n_rx || n_rx > CQSPI_STIG_DATA_LEN_MAX || !rxbuf) {
+               dev_err(nor->dev, "Invalid input argument, len %d rxbuf 0x%p\n",
+                       n_rx, rxbuf);
+               return -EINVAL;
+       }
+
+       reg = txbuf[0] << CQSPI_REG_CMDCTRL_OPCODE_LSB;
+
+       rdreg = cqspi_calc_rdreg(nor, txbuf[0]);
+       writel(rdreg, reg_base + CQSPI_REG_RD_INSTR);
+
+       reg |= (0x1 << CQSPI_REG_CMDCTRL_RD_EN_LSB);
+
+       /* 0 means 1 byte. */
+       reg |= (((n_rx - 1) & CQSPI_REG_CMDCTRL_RD_BYTES_MASK)
+               << CQSPI_REG_CMDCTRL_RD_BYTES_LSB);
+       status = cqspi_exec_flash_cmd(cqspi, reg);
+       if (status)
+               return status;
+
+       reg = readl(reg_base + CQSPI_REG_CMDREADDATALOWER);
+
+       /* Put the read value into rx_buf */
+       read_len = (n_rx > 4) ? 4 : n_rx;
+       memcpy(rxbuf, &reg, read_len);
+       rxbuf += read_len;
+
+       if (n_rx > 4) {
+               reg = readl(reg_base + CQSPI_REG_CMDREADDATAUPPER);
+
+               read_len = n_rx - read_len;
+               memcpy(rxbuf, &reg, read_len);
+       }
+
+       return 0;
+}
+
+static int cqspi_command_write(struct spi_nor *nor, const u8 opcode,
+                              const u8 *txbuf, const unsigned n_tx)
+{
+       struct cqspi_flash_pdata *f_pdata = nor->priv;
+       struct cqspi_st *cqspi = f_pdata->cqspi;
+       void __iomem *reg_base = cqspi->iobase;
+       unsigned int reg;
+       unsigned int data;
+       int ret;
+
+       if (n_tx > 4 || (n_tx && !txbuf)) {
+               dev_err(nor->dev,
+                       "Invalid input argument, cmdlen %d txbuf 0x%p\n",
+                       n_tx, txbuf);
+               return -EINVAL;
+       }
+
+       reg = opcode << CQSPI_REG_CMDCTRL_OPCODE_LSB;
+       if (n_tx) {
+               reg |= (0x1 << CQSPI_REG_CMDCTRL_WR_EN_LSB);
+               reg |= ((n_tx - 1) & CQSPI_REG_CMDCTRL_WR_BYTES_MASK)
+                       << CQSPI_REG_CMDCTRL_WR_BYTES_LSB;
+               data = 0;
+               memcpy(&data, txbuf, n_tx);
+               writel(data, reg_base + CQSPI_REG_CMDWRITEDATALOWER);
+       }
+
+       ret = cqspi_exec_flash_cmd(cqspi, reg);
+       return ret;
+}
+
+static int cqspi_command_write_addr(struct spi_nor *nor,
+                                   const u8 opcode, const unsigned int addr)
+{
+       struct cqspi_flash_pdata *f_pdata = nor->priv;
+       struct cqspi_st *cqspi = f_pdata->cqspi;
+       void __iomem *reg_base = cqspi->iobase;
+       unsigned int reg;
+
+       reg = opcode << CQSPI_REG_CMDCTRL_OPCODE_LSB;
+       reg |= (0x1 << CQSPI_REG_CMDCTRL_ADDR_EN_LSB);
+       reg |= ((nor->addr_width - 1) & CQSPI_REG_CMDCTRL_ADD_BYTES_MASK)
+               << CQSPI_REG_CMDCTRL_ADD_BYTES_LSB;
+
+       writel(addr, reg_base + CQSPI_REG_CMDADDRESS);
+
+       return cqspi_exec_flash_cmd(cqspi, reg);
+}
+
+static int cqspi_indirect_read_setup(struct spi_nor *nor,
+                                    const unsigned int from_addr)
+{
+       struct cqspi_flash_pdata *f_pdata = nor->priv;
+       struct cqspi_st *cqspi = f_pdata->cqspi;
+       void __iomem *reg_base = cqspi->iobase;
+       unsigned int dummy_clk = 0;
+       unsigned int reg;
+
+       writel(from_addr, reg_base + CQSPI_REG_INDIRECTRDSTARTADDR);
+
+       reg = nor->read_opcode << CQSPI_REG_RD_INSTR_OPCODE_LSB;
+       reg |= cqspi_calc_rdreg(nor, nor->read_opcode);
+
+       /* Setup dummy clock cycles */
+       dummy_clk = nor->read_dummy;
+       if (dummy_clk > CQSPI_DUMMY_CLKS_MAX)
+               dummy_clk = CQSPI_DUMMY_CLKS_MAX;
+
+       if (dummy_clk / 8) {
+               reg |= (1 << CQSPI_REG_RD_INSTR_MODE_EN_LSB);
+               /* Set mode bits high to ensure chip doesn't enter XIP */
+               writel(0xFF, reg_base + CQSPI_REG_MODE_BIT);
+
+               /* Need to subtract the mode byte (8 clocks). */
+               if (f_pdata->inst_width != CQSPI_INST_TYPE_QUAD)
+                       dummy_clk -= 8;
+
+               if (dummy_clk)
+                       reg |= (dummy_clk & CQSPI_REG_RD_INSTR_DUMMY_MASK)
+                              << CQSPI_REG_RD_INSTR_DUMMY_LSB;
+       }
+
+       writel(reg, reg_base + CQSPI_REG_RD_INSTR);
+
+       /* Set address width */
+       reg = readl(reg_base + CQSPI_REG_SIZE);
+       reg &= ~CQSPI_REG_SIZE_ADDRESS_MASK;
+       reg |= (nor->addr_width - 1);
+       writel(reg, reg_base + CQSPI_REG_SIZE);
+       return 0;
+}
+
+static int cqspi_indirect_read_execute(struct spi_nor *nor,
+                                      u8 *rxbuf, const unsigned n_rx)
+{
+       struct cqspi_flash_pdata *f_pdata = nor->priv;
+       struct cqspi_st *cqspi = f_pdata->cqspi;
+       void __iomem *reg_base = cqspi->iobase;
+       void __iomem *ahb_base = cqspi->ahb_base;
+       unsigned int remaining = n_rx;
+       unsigned int bytes_to_read = 0;
+       int ret = 0;
+
+       writel(remaining, reg_base + CQSPI_REG_INDIRECTRDBYTES);
+
+       /* Clear all interrupts. */
+       writel(CQSPI_IRQ_STATUS_MASK, reg_base + CQSPI_REG_IRQSTATUS);
+
+       writel(CQSPI_IRQ_MASK_RD, reg_base + CQSPI_REG_IRQMASK);
+
+       reinit_completion(&cqspi->transfer_complete);
+       writel(CQSPI_REG_INDIRECTRD_START_MASK,
+              reg_base + CQSPI_REG_INDIRECTRD);
+
+       while (remaining > 0) {
+               ret = wait_for_completion_timeout(&cqspi->transfer_complete,
+                                                 msecs_to_jiffies
+                                                 (CQSPI_READ_TIMEOUT_MS));
+
+               bytes_to_read = cqspi_get_rd_sram_level(cqspi);
+
+               if (!ret && bytes_to_read == 0) {
+                       dev_err(nor->dev, "Indirect read timeout, no bytes\n");
+                       ret = -ETIMEDOUT;
+                       goto failrd;
+               }
+
+               while (bytes_to_read != 0) {
+                       bytes_to_read *= cqspi->fifo_width;
+                       bytes_to_read = bytes_to_read > remaining ?
+                                       remaining : bytes_to_read;
+                       readsl(ahb_base, rxbuf, DIV_ROUND_UP(bytes_to_read, 4));
+                       rxbuf += bytes_to_read;
+                       remaining -= bytes_to_read;
+                       bytes_to_read = cqspi_get_rd_sram_level(cqspi);
+               }
+
+               if (remaining > 0)
+                       reinit_completion(&cqspi->transfer_complete);
+       }
+
+       /* Check indirect done status */
+       ret = cqspi_wait_for_bit(reg_base + CQSPI_REG_INDIRECTRD,
+                                CQSPI_REG_INDIRECTRD_DONE_MASK, 0);
+       if (ret) {
+               dev_err(nor->dev,
+                       "Indirect read completion error (%i)\n", ret);
+               goto failrd;
+       }
+
+       /* Disable interrupt */
+       writel(0, reg_base + CQSPI_REG_IRQMASK);
+
+       /* Clear indirect completion status */
+       writel(CQSPI_REG_INDIRECTRD_DONE_MASK, reg_base + CQSPI_REG_INDIRECTRD);
+
+       return 0;
+
+failrd:
+       /* Disable interrupt */
+       writel(0, reg_base + CQSPI_REG_IRQMASK);
+
+       /* Cancel the indirect read */
+       writel(CQSPI_REG_INDIRECTWR_CANCEL_MASK,
+              reg_base + CQSPI_REG_INDIRECTRD);
+       return ret;
+}
+
+static int cqspi_indirect_write_setup(struct spi_nor *nor,
+                                     const unsigned int to_addr)
+{
+       unsigned int reg;
+       struct cqspi_flash_pdata *f_pdata = nor->priv;
+       struct cqspi_st *cqspi = f_pdata->cqspi;
+       void __iomem *reg_base = cqspi->iobase;
+
+       /* Set opcode. */
+       reg = nor->program_opcode << CQSPI_REG_WR_INSTR_OPCODE_LSB;
+       writel(reg, reg_base + CQSPI_REG_WR_INSTR);
+       reg = cqspi_calc_rdreg(nor, nor->program_opcode);
+       writel(reg, reg_base + CQSPI_REG_RD_INSTR);
+
+       writel(to_addr, reg_base + CQSPI_REG_INDIRECTWRSTARTADDR);
+
+       reg = readl(reg_base + CQSPI_REG_SIZE);
+       reg &= ~CQSPI_REG_SIZE_ADDRESS_MASK;
+       reg |= (nor->addr_width - 1);
+       writel(reg, reg_base + CQSPI_REG_SIZE);
+       return 0;
+}
+
+static int cqspi_indirect_write_execute(struct spi_nor *nor,
+                                       const u8 *txbuf, const unsigned n_tx)
+{
+       const unsigned int page_size = nor->page_size;
+       struct cqspi_flash_pdata *f_pdata = nor->priv;
+       struct cqspi_st *cqspi = f_pdata->cqspi;
+       void __iomem *reg_base = cqspi->iobase;
+       unsigned int remaining = n_tx;
+       unsigned int write_bytes;
+       int ret;
+
+       writel(remaining, reg_base + CQSPI_REG_INDIRECTWRBYTES);
+
+       /* Clear all interrupts. */
+       writel(CQSPI_IRQ_STATUS_MASK, reg_base + CQSPI_REG_IRQSTATUS);
+
+       writel(CQSPI_IRQ_MASK_WR, reg_base + CQSPI_REG_IRQMASK);
+
+       reinit_completion(&cqspi->transfer_complete);
+       writel(CQSPI_REG_INDIRECTWR_START_MASK,
+              reg_base + CQSPI_REG_INDIRECTWR);
+
+       while (remaining > 0) {
+               write_bytes = remaining > page_size ? page_size : remaining;
+               writesl(cqspi->ahb_base, txbuf, DIV_ROUND_UP(write_bytes, 4));
+
+               ret = wait_for_completion_timeout(&cqspi->transfer_complete,
+                                                 msecs_to_jiffies
+                                                 (CQSPI_TIMEOUT_MS));
+               if (!ret) {
+                       dev_err(nor->dev, "Indirect write timeout\n");
+                       ret = -ETIMEDOUT;
+                       goto failwr;
+               }
+
+               txbuf += write_bytes;
+               remaining -= write_bytes;
+
+               if (remaining > 0)
+                       reinit_completion(&cqspi->transfer_complete);
+       }
+
+       /* Check indirect done status */
+       ret = cqspi_wait_for_bit(reg_base + CQSPI_REG_INDIRECTWR,
+                                CQSPI_REG_INDIRECTWR_DONE_MASK, 0);
+       if (ret) {
+               dev_err(nor->dev,
+                       "Indirect write completion error (%i)\n", ret);
+               goto failwr;
+       }
+
+       /* Disable interrupt. */
+       writel(0, reg_base + CQSPI_REG_IRQMASK);
+
+       /* Clear indirect completion status */
+       writel(CQSPI_REG_INDIRECTWR_DONE_MASK, reg_base + CQSPI_REG_INDIRECTWR);
+
+       cqspi_wait_idle(cqspi);
+
+       return 0;
+
+failwr:
+       /* Disable interrupt. */
+       writel(0, reg_base + CQSPI_REG_IRQMASK);
+
+       /* Cancel the indirect write */
+       writel(CQSPI_REG_INDIRECTWR_CANCEL_MASK,
+              reg_base + CQSPI_REG_INDIRECTWR);
+       return ret;
+}
+
+static void cqspi_chipselect(struct spi_nor *nor)
+{
+       struct cqspi_flash_pdata *f_pdata = nor->priv;
+       struct cqspi_st *cqspi = f_pdata->cqspi;
+       void __iomem *reg_base = cqspi->iobase;
+       unsigned int chip_select = f_pdata->cs;
+       unsigned int reg;
+
+       reg = readl(reg_base + CQSPI_REG_CONFIG);
+       if (cqspi->is_decoded_cs) {
+               reg |= CQSPI_REG_CONFIG_DECODE_MASK;
+       } else {
+               reg &= ~CQSPI_REG_CONFIG_DECODE_MASK;
+
+               /* Convert CS if without decoder.
+                * CS0 to 4b'1110
+                * CS1 to 4b'1101
+                * CS2 to 4b'1011
+                * CS3 to 4b'0111
+                */
+               chip_select = 0xF & ~(1 << chip_select);
+       }
+
+       reg &= ~(CQSPI_REG_CONFIG_CHIPSELECT_MASK
+                << CQSPI_REG_CONFIG_CHIPSELECT_LSB);
+       reg |= (chip_select & CQSPI_REG_CONFIG_CHIPSELECT_MASK)
+           << CQSPI_REG_CONFIG_CHIPSELECT_LSB;
+       writel(reg, reg_base + CQSPI_REG_CONFIG);
+}
+
+static void cqspi_configure_cs_and_sizes(struct spi_nor *nor)
+{
+       struct cqspi_flash_pdata *f_pdata = nor->priv;
+       struct cqspi_st *cqspi = f_pdata->cqspi;
+       void __iomem *iobase = cqspi->iobase;
+       unsigned int reg;
+
+       /* configure page size and block size. */
+       reg = readl(iobase + CQSPI_REG_SIZE);
+       reg &= ~(CQSPI_REG_SIZE_PAGE_MASK << CQSPI_REG_SIZE_PAGE_LSB);
+       reg &= ~(CQSPI_REG_SIZE_BLOCK_MASK << CQSPI_REG_SIZE_BLOCK_LSB);
+       reg &= ~CQSPI_REG_SIZE_ADDRESS_MASK;
+       reg |= (nor->page_size << CQSPI_REG_SIZE_PAGE_LSB);
+       reg |= (ilog2(nor->mtd.erasesize) << CQSPI_REG_SIZE_BLOCK_LSB);
+       reg |= (nor->addr_width - 1);
+       writel(reg, iobase + CQSPI_REG_SIZE);
+
+       /* configure the chip select */
+       cqspi_chipselect(nor);
+
+       /* Store the new configuration of the controller */
+       cqspi->current_page_size = nor->page_size;
+       cqspi->current_erase_size = nor->mtd.erasesize;
+       cqspi->current_addr_width = nor->addr_width;
+}
+
+static unsigned int calculate_ticks_for_ns(const unsigned int ref_clk_hz,
+                                          const unsigned int ns_val)
+{
+       unsigned int ticks;
+
+       ticks = ref_clk_hz / 1000;      /* kHz */
+       ticks = DIV_ROUND_UP(ticks * ns_val, 1000000);
+
+       return ticks;
+}
+
+static void cqspi_delay(struct spi_nor *nor)
+{
+       struct cqspi_flash_pdata *f_pdata = nor->priv;
+       struct cqspi_st *cqspi = f_pdata->cqspi;
+       void __iomem *iobase = cqspi->iobase;
+       const unsigned int ref_clk_hz = cqspi->master_ref_clk_hz;
+       unsigned int tshsl, tchsh, tslch, tsd2d;
+       unsigned int reg;
+       unsigned int tsclk;
+
+       /* calculate the number of ref ticks for one sclk tick */
+       tsclk = DIV_ROUND_UP(ref_clk_hz, cqspi->sclk);
+
+       tshsl = calculate_ticks_for_ns(ref_clk_hz, f_pdata->tshsl_ns);
+       /* this particular value must be at least one sclk */
+       if (tshsl < tsclk)
+               tshsl = tsclk;
+
+       tchsh = calculate_ticks_for_ns(ref_clk_hz, f_pdata->tchsh_ns);
+       tslch = calculate_ticks_for_ns(ref_clk_hz, f_pdata->tslch_ns);
+       tsd2d = calculate_ticks_for_ns(ref_clk_hz, f_pdata->tsd2d_ns);
+
+       reg = (tshsl & CQSPI_REG_DELAY_TSHSL_MASK)
+              << CQSPI_REG_DELAY_TSHSL_LSB;
+       reg |= (tchsh & CQSPI_REG_DELAY_TCHSH_MASK)
+               << CQSPI_REG_DELAY_TCHSH_LSB;
+       reg |= (tslch & CQSPI_REG_DELAY_TSLCH_MASK)
+               << CQSPI_REG_DELAY_TSLCH_LSB;
+       reg |= (tsd2d & CQSPI_REG_DELAY_TSD2D_MASK)
+               << CQSPI_REG_DELAY_TSD2D_LSB;
+       writel(reg, iobase + CQSPI_REG_DELAY);
+}
+
+static void cqspi_config_baudrate_div(struct cqspi_st *cqspi)
+{
+       const unsigned int ref_clk_hz = cqspi->master_ref_clk_hz;
+       void __iomem *reg_base = cqspi->iobase;
+       u32 reg, div;
+
+       /* Recalculate the baudrate divisor based on QSPI specification. */
+       div = DIV_ROUND_UP(ref_clk_hz, 2 * cqspi->sclk) - 1;
+
+       reg = readl(reg_base + CQSPI_REG_CONFIG);
+       reg &= ~(CQSPI_REG_CONFIG_BAUD_MASK << CQSPI_REG_CONFIG_BAUD_LSB);
+       reg |= (div & CQSPI_REG_CONFIG_BAUD_MASK) << CQSPI_REG_CONFIG_BAUD_LSB;
+       writel(reg, reg_base + CQSPI_REG_CONFIG);
+}
+
+static void cqspi_readdata_capture(struct cqspi_st *cqspi,
+                                  const unsigned int bypass,
+                                  const unsigned int delay)
+{
+       void __iomem *reg_base = cqspi->iobase;
+       unsigned int reg;
+
+       reg = readl(reg_base + CQSPI_REG_READCAPTURE);
+
+       if (bypass)
+               reg |= (1 << CQSPI_REG_READCAPTURE_BYPASS_LSB);
+       else
+               reg &= ~(1 << CQSPI_REG_READCAPTURE_BYPASS_LSB);
+
+       reg &= ~(CQSPI_REG_READCAPTURE_DELAY_MASK
+                << CQSPI_REG_READCAPTURE_DELAY_LSB);
+
+       reg |= (delay & CQSPI_REG_READCAPTURE_DELAY_MASK)
+               << CQSPI_REG_READCAPTURE_DELAY_LSB;
+
+       writel(reg, reg_base + CQSPI_REG_READCAPTURE);
+}
+
+static void cqspi_controller_enable(struct cqspi_st *cqspi, bool enable)
+{
+       void __iomem *reg_base = cqspi->iobase;
+       unsigned int reg;
+
+       reg = readl(reg_base + CQSPI_REG_CONFIG);
+
+       if (enable)
+               reg |= CQSPI_REG_CONFIG_ENABLE_MASK;
+       else
+               reg &= ~CQSPI_REG_CONFIG_ENABLE_MASK;
+
+       writel(reg, reg_base + CQSPI_REG_CONFIG);
+}
+
+static void cqspi_configure(struct spi_nor *nor)
+{
+       struct cqspi_flash_pdata *f_pdata = nor->priv;
+       struct cqspi_st *cqspi = f_pdata->cqspi;
+       const unsigned int sclk = f_pdata->clk_rate;
+       int switch_cs = (cqspi->current_cs != f_pdata->cs);
+       int switch_ck = (cqspi->sclk != sclk);
+
+       if ((cqspi->current_page_size != nor->page_size) ||
+           (cqspi->current_erase_size != nor->mtd.erasesize) ||
+           (cqspi->current_addr_width != nor->addr_width))
+               switch_cs = 1;
+
+       if (switch_cs || switch_ck)
+               cqspi_controller_enable(cqspi, 0);
+
+       /* Switch chip select. */
+       if (switch_cs) {
+               cqspi->current_cs = f_pdata->cs;
+               cqspi_configure_cs_and_sizes(nor);
+       }
+
+       /* Setup baudrate divisor and delays */
+       if (switch_ck) {
+               cqspi->sclk = sclk;
+               cqspi_config_baudrate_div(cqspi);
+               cqspi_delay(nor);
+               cqspi_readdata_capture(cqspi, 1, f_pdata->read_delay);
+       }
+
+       if (switch_cs || switch_ck)
+               cqspi_controller_enable(cqspi, 1);
+}
+
+static int cqspi_set_protocol(struct spi_nor *nor, const int read)
+{
+       struct cqspi_flash_pdata *f_pdata = nor->priv;
+
+       f_pdata->inst_width = CQSPI_INST_TYPE_SINGLE;
+       f_pdata->addr_width = CQSPI_INST_TYPE_SINGLE;
+       f_pdata->data_width = CQSPI_INST_TYPE_SINGLE;
+
+       if (read) {
+               switch (nor->flash_read) {
+               case SPI_NOR_NORMAL:
+               case SPI_NOR_FAST:
+                       f_pdata->data_width = CQSPI_INST_TYPE_SINGLE;
+                       break;
+               case SPI_NOR_DUAL:
+                       f_pdata->data_width = CQSPI_INST_TYPE_DUAL;
+                       break;
+               case SPI_NOR_QUAD:
+                       f_pdata->data_width = CQSPI_INST_TYPE_QUAD;
+                       break;
+               default:
+                       return -EINVAL;
+               }
+       }
+
+       cqspi_configure(nor);
+
+       return 0;
+}
+
+static ssize_t cqspi_write(struct spi_nor *nor, loff_t to,
+                          size_t len, const u_char *buf)
+{
+       int ret;
+
+       ret = cqspi_set_protocol(nor, 0);
+       if (ret)
+               return ret;
+
+       ret = cqspi_indirect_write_setup(nor, to);
+       if (ret)
+               return ret;
+
+       ret = cqspi_indirect_write_execute(nor, buf, len);
+       if (ret)
+               return ret;
+
+       return (ret < 0) ? ret : len;
+}
+
+static ssize_t cqspi_read(struct spi_nor *nor, loff_t from,
+                         size_t len, u_char *buf)
+{
+       int ret;
+
+       ret = cqspi_set_protocol(nor, 1);
+       if (ret)
+               return ret;
+
+       ret = cqspi_indirect_read_setup(nor, from);
+       if (ret)
+               return ret;
+
+       ret = cqspi_indirect_read_execute(nor, buf, len);
+       if (ret)
+               return ret;
+
+       return (ret < 0) ? ret : len;
+}
+
+static int cqspi_erase(struct spi_nor *nor, loff_t offs)
+{
+       int ret;
+
+       ret = cqspi_set_protocol(nor, 0);
+       if (ret)
+               return ret;
+
+       /* Send write enable, then erase commands. */
+       ret = nor->write_reg(nor, SPINOR_OP_WREN, NULL, 0);
+       if (ret)
+               return ret;
+
+       /* Set up command buffer. */
+       ret = cqspi_command_write_addr(nor, nor->erase_opcode, offs);
+       if (ret)
+               return ret;
+
+       return 0;
+}
+
+static int cqspi_prep(struct spi_nor *nor, enum spi_nor_ops ops)
+{
+       struct cqspi_flash_pdata *f_pdata = nor->priv;
+       struct cqspi_st *cqspi = f_pdata->cqspi;
+
+       mutex_lock(&cqspi->bus_mutex);
+
+       return 0;
+}
+
+static void cqspi_unprep(struct spi_nor *nor, enum spi_nor_ops ops)
+{
+       struct cqspi_flash_pdata *f_pdata = nor->priv;
+       struct cqspi_st *cqspi = f_pdata->cqspi;
+
+       mutex_unlock(&cqspi->bus_mutex);
+}
+
+static int cqspi_read_reg(struct spi_nor *nor, u8 opcode, u8 *buf, int len)
+{
+       int ret;
+
+       ret = cqspi_set_protocol(nor, 0);
+       if (!ret)
+               ret = cqspi_command_read(nor, &opcode, 1, buf, len);
+
+       return ret;
+}
+
+static int cqspi_write_reg(struct spi_nor *nor, u8 opcode, u8 *buf, int len)
+{
+       int ret;
+
+       ret = cqspi_set_protocol(nor, 0);
+       if (!ret)
+               ret = cqspi_command_write(nor, opcode, buf, len);
+
+       return ret;
+}
+
+static int cqspi_of_get_flash_pdata(struct platform_device *pdev,
+                                   struct cqspi_flash_pdata *f_pdata,
+                                   struct device_node *np)
+{
+       if (of_property_read_u32(np, "cdns,read-delay", &f_pdata->read_delay)) {
+               dev_err(&pdev->dev, "couldn't determine read-delay\n");
+               return -ENXIO;
+       }
+
+       if (of_property_read_u32(np, "cdns,tshsl-ns", &f_pdata->tshsl_ns)) {
+               dev_err(&pdev->dev, "couldn't determine tshsl-ns\n");
+               return -ENXIO;
+       }
+
+       if (of_property_read_u32(np, "cdns,tsd2d-ns", &f_pdata->tsd2d_ns)) {
+               dev_err(&pdev->dev, "couldn't determine tsd2d-ns\n");
+               return -ENXIO;
+       }
+
+       if (of_property_read_u32(np, "cdns,tchsh-ns", &f_pdata->tchsh_ns)) {
+               dev_err(&pdev->dev, "couldn't determine tchsh-ns\n");
+               return -ENXIO;
+       }
+
+       if (of_property_read_u32(np, "cdns,tslch-ns", &f_pdata->tslch_ns)) {
+               dev_err(&pdev->dev, "couldn't determine tslch-ns\n");
+               return -ENXIO;
+       }
+
+       if (of_property_read_u32(np, "spi-max-frequency", &f_pdata->clk_rate)) {
+               dev_err(&pdev->dev, "couldn't determine spi-max-frequency\n");
+               return -ENXIO;
+       }
+
+       return 0;
+}
+
+static int cqspi_of_get_pdata(struct platform_device *pdev)
+{
+       struct device_node *np = pdev->dev.of_node;
+       struct cqspi_st *cqspi = platform_get_drvdata(pdev);
+
+       cqspi->is_decoded_cs = of_property_read_bool(np, "cdns,is-decoded-cs");
+
+       if (of_property_read_u32(np, "cdns,fifo-depth", &cqspi->fifo_depth)) {
+               dev_err(&pdev->dev, "couldn't determine fifo-depth\n");
+               return -ENXIO;
+       }
+
+       if (of_property_read_u32(np, "cdns,fifo-width", &cqspi->fifo_width)) {
+               dev_err(&pdev->dev, "couldn't determine fifo-width\n");
+               return -ENXIO;
+       }
+
+       if (of_property_read_u32(np, "cdns,trigger-address",
+                                &cqspi->trigger_address)) {
+               dev_err(&pdev->dev, "couldn't determine trigger-address\n");
+               return -ENXIO;
+       }
+
+       return 0;
+}
+
+static void cqspi_controller_init(struct cqspi_st *cqspi)
+{
+       cqspi_controller_enable(cqspi, 0);
+
+       /* Configure the remap address register, no remap */
+       writel(0, cqspi->iobase + CQSPI_REG_REMAP);
+
+       /* Disable all interrupts. */
+       writel(0, cqspi->iobase + CQSPI_REG_IRQMASK);
+
+       /* Configure the SRAM split to 1:1 . */
+       writel(cqspi->fifo_depth / 2, cqspi->iobase + CQSPI_REG_SRAMPARTITION);
+
+       /* Load indirect trigger address. */
+       writel(cqspi->trigger_address,
+              cqspi->iobase + CQSPI_REG_INDIRECTTRIGGER);
+
+       /* Program read watermark -- 1/2 of the FIFO. */
+       writel(cqspi->fifo_depth * cqspi->fifo_width / 2,
+              cqspi->iobase + CQSPI_REG_INDIRECTRDWATERMARK);
+       /* Program write watermark -- 1/8 of the FIFO. */
+       writel(cqspi->fifo_depth * cqspi->fifo_width / 8,
+              cqspi->iobase + CQSPI_REG_INDIRECTWRWATERMARK);
+
+       cqspi_controller_enable(cqspi, 1);
+}
+
+static int cqspi_setup_flash(struct cqspi_st *cqspi, struct device_node *np)
+{
+       struct platform_device *pdev = cqspi->pdev;
+       struct device *dev = &pdev->dev;
+       struct cqspi_flash_pdata *f_pdata;
+       struct spi_nor *nor;
+       struct mtd_info *mtd;
+       unsigned int cs;
+       int i, ret;
+
+       /* Get flash device data */
+       for_each_available_child_of_node(dev->of_node, np) {
+               if (of_property_read_u32(np, "reg", &cs)) {
+                       dev_err(dev, "Couldn't determine chip select.\n");
+                       goto err;
+               }
+
+               if (cs > CQSPI_MAX_CHIPSELECT) {
+                       dev_err(dev, "Chip select %d out of range.\n", cs);
+                       goto err;
+               }
+
+               f_pdata = &cqspi->f_pdata[cs];
+               f_pdata->cqspi = cqspi;
+               f_pdata->cs = cs;
+
+               ret = cqspi_of_get_flash_pdata(pdev, f_pdata, np);
+               if (ret)
+                       goto err;
+
+               nor = &f_pdata->nor;
+               mtd = &nor->mtd;
+
+               mtd->priv = nor;
+
+               nor->dev = dev;
+               spi_nor_set_flash_node(nor, np);
+               nor->priv = f_pdata;
+
+               nor->read_reg = cqspi_read_reg;
+               nor->write_reg = cqspi_write_reg;
+               nor->read = cqspi_read;
+               nor->write = cqspi_write;
+               nor->erase = cqspi_erase;
+               nor->prepare = cqspi_prep;
+               nor->unprepare = cqspi_unprep;
+
+               mtd->name = devm_kasprintf(dev, GFP_KERNEL, "%s.%d",
+                                          dev_name(dev), cs);
+               if (!mtd->name) {
+                       ret = -ENOMEM;
+                       goto err;
+               }
+
+               ret = spi_nor_scan(nor, NULL, SPI_NOR_QUAD);
+               if (ret)
+                       goto err;
+
+               ret = mtd_device_register(mtd, NULL, 0);
+               if (ret)
+                       goto err;
+
+               f_pdata->registered = true;
+       }
+
+       return 0;
+
+err:
+       for (i = 0; i < CQSPI_MAX_CHIPSELECT; i++)
+               if (cqspi->f_pdata[i].registered)
+                       mtd_device_unregister(&cqspi->f_pdata[i].nor.mtd);
+       return ret;
+}
+
+static int cqspi_probe(struct platform_device *pdev)
+{
+       struct device_node *np = pdev->dev.of_node;
+       struct device *dev = &pdev->dev;
+       struct cqspi_st *cqspi;
+       struct resource *res;
+       struct resource *res_ahb;
+       int ret;
+       int irq;
+
+       cqspi = devm_kzalloc(dev, sizeof(*cqspi), GFP_KERNEL);
+       if (!cqspi)
+               return -ENOMEM;
+
+       mutex_init(&cqspi->bus_mutex);
+       cqspi->pdev = pdev;
+       platform_set_drvdata(pdev, cqspi);
+
+       /* Obtain configuration from OF. */
+       ret = cqspi_of_get_pdata(pdev);
+       if (ret) {
+               dev_err(dev, "Cannot get mandatory OF data.\n");
+               return -ENODEV;
+       }
+
+       /* Obtain QSPI clock. */
+       cqspi->clk = devm_clk_get(dev, NULL);
+       if (IS_ERR(cqspi->clk)) {
+               dev_err(dev, "Cannot claim QSPI clock.\n");
+               return PTR_ERR(cqspi->clk);
+       }
+
+       /* Obtain and remap controller address. */
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       cqspi->iobase = devm_ioremap_resource(dev, res);
+       if (IS_ERR(cqspi->iobase)) {
+               dev_err(dev, "Cannot remap controller address.\n");
+               return PTR_ERR(cqspi->iobase);
+       }
+
+       /* Obtain and remap AHB address. */
+       res_ahb = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+       cqspi->ahb_base = devm_ioremap_resource(dev, res_ahb);
+       if (IS_ERR(cqspi->ahb_base)) {
+               dev_err(dev, "Cannot remap AHB address.\n");
+               return PTR_ERR(cqspi->ahb_base);
+       }
+
+       init_completion(&cqspi->transfer_complete);
+
+       /* Obtain IRQ line. */
+       irq = platform_get_irq(pdev, 0);
+       if (irq < 0) {
+               dev_err(dev, "Cannot obtain IRQ.\n");
+               return -ENXIO;
+       }
+
+       ret = clk_prepare_enable(cqspi->clk);
+       if (ret) {
+               dev_err(dev, "Cannot enable QSPI clock.\n");
+               return ret;
+       }
+
+       cqspi->master_ref_clk_hz = clk_get_rate(cqspi->clk);
+
+       ret = devm_request_irq(dev, irq, cqspi_irq_handler, 0,
+                              pdev->name, cqspi);
+       if (ret) {
+               dev_err(dev, "Cannot request IRQ.\n");
+               goto probe_irq_failed;
+       }
+
+       cqspi_wait_idle(cqspi);
+       cqspi_controller_init(cqspi);
+       cqspi->current_cs = -1;
+       cqspi->sclk = 0;
+
+       ret = cqspi_setup_flash(cqspi, np);
+       if (ret) {
+               dev_err(dev, "Cadence QSPI NOR probe failed %d\n", ret);
+               goto probe_setup_failed;
+       }
+
+       return ret;
+probe_irq_failed:
+       cqspi_controller_enable(cqspi, 0);
+probe_setup_failed:
+       clk_disable_unprepare(cqspi->clk);
+       return ret;
+}
+
+static int cqspi_remove(struct platform_device *pdev)
+{
+       struct cqspi_st *cqspi = platform_get_drvdata(pdev);
+       int i;
+
+       for (i = 0; i < CQSPI_MAX_CHIPSELECT; i++)
+               if (cqspi->f_pdata[i].registered)
+                       mtd_device_unregister(&cqspi->f_pdata[i].nor.mtd);
+
+       cqspi_controller_enable(cqspi, 0);
+
+       clk_disable_unprepare(cqspi->clk);
+
+       return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int cqspi_suspend(struct device *dev)
+{
+       struct cqspi_st *cqspi = dev_get_drvdata(dev);
+
+       cqspi_controller_enable(cqspi, 0);
+       return 0;
+}
+
+static int cqspi_resume(struct device *dev)
+{
+       struct cqspi_st *cqspi = dev_get_drvdata(dev);
+
+       cqspi_controller_enable(cqspi, 1);
+       return 0;
+}
+
+static const struct dev_pm_ops cqspi__dev_pm_ops = {
+       .suspend = cqspi_suspend,
+       .resume = cqspi_resume,
+};
+
+#define CQSPI_DEV_PM_OPS       (&cqspi__dev_pm_ops)
+#else
+#define CQSPI_DEV_PM_OPS       NULL
+#endif
+
+static struct of_device_id const cqspi_dt_ids[] = {
+       {.compatible = "cdns,qspi-nor",},
+       { /* end of table */ }
+};
+
+MODULE_DEVICE_TABLE(of, cqspi_dt_ids);
+
+static struct platform_driver cqspi_platform_driver = {
+       .probe = cqspi_probe,
+       .remove = cqspi_remove,
+       .driver = {
+               .name = CQSPI_NAME,
+               .pm = CQSPI_DEV_PM_OPS,
+               .of_match_table = cqspi_dt_ids,
+       },
+};
+
+module_platform_driver(cqspi_platform_driver);
+
+MODULE_DESCRIPTION("Cadence QSPI Controller Driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:" CQSPI_NAME);
+MODULE_AUTHOR("Ley Foon Tan <lftan@altera.com>");
+MODULE_AUTHOR("Graham Moore <grmoore@opensource.altera.com>");