/*
   * SPI bus driver for CSR SiRFprimaII
   *
   * Copyright (c) 2011 Cambridge Silicon Radio Limited, a CSR plc group company.
   *
   * Licensed under GPLv2 or later.
   */
  
  #include <linux/module.h>
  #include <linux/kernel.h>
  #include <linux/slab.h>
  #include <linux/clk.h>
  #include <linux/completion.h>
  #include <linux/interrupt.h>
  #include <linux/io.h>
  #include <linux/of.h>
  #include <linux/bitops.h>
  #include <linux/err.h>
  #include <linux/platform_device.h>
  #include <linux/of_gpio.h>
  #include <linux/spi/spi.h>
  #include <linux/spi/spi_bitbang.h>
  #include <linux/dmaengine.h>
  #include <linux/dma-direction.h>
  #include <linux/dma-mapping.h>
  #include <linux/reset.h>
  
  #define DRIVER_NAME "sirfsoc_spi"
  /* SPI CTRL register defines */
  #define SIRFSOC_SPI_SLV_MODE		BIT(16)
  #define SIRFSOC_SPI_CMD_MODE		BIT(17)
  #define SIRFSOC_SPI_CS_IO_OUT		BIT(18)
  #define SIRFSOC_SPI_CS_IO_MODE		BIT(19)
  #define SIRFSOC_SPI_CLK_IDLE_STAT	BIT(20)
  #define SIRFSOC_SPI_CS_IDLE_STAT	BIT(21)
  #define SIRFSOC_SPI_TRAN_MSB		BIT(22)
  #define SIRFSOC_SPI_DRV_POS_EDGE	BIT(23)
  #define SIRFSOC_SPI_CS_HOLD_TIME	BIT(24)
  #define SIRFSOC_SPI_CLK_SAMPLE_MODE	BIT(25)
  #define SIRFSOC_SPI_TRAN_DAT_FORMAT_8	(0 << 26)
  #define SIRFSOC_SPI_TRAN_DAT_FORMAT_12	(1 << 26)
  #define SIRFSOC_SPI_TRAN_DAT_FORMAT_16	(2 << 26)
  #define SIRFSOC_SPI_TRAN_DAT_FORMAT_32	(3 << 26)
  #define SIRFSOC_SPI_CMD_BYTE_NUM(x)	((x & 3) << 28)
  #define SIRFSOC_SPI_ENA_AUTO_CLR	BIT(30)
  #define SIRFSOC_SPI_MUL_DAT_MODE	BIT(31)
  
  /* Interrupt Enable */
  #define SIRFSOC_SPI_RX_DONE_INT_EN	BIT(0)
  #define SIRFSOC_SPI_TX_DONE_INT_EN	BIT(1)
  #define SIRFSOC_SPI_RX_OFLOW_INT_EN	BIT(2)
  #define SIRFSOC_SPI_TX_UFLOW_INT_EN	BIT(3)
  #define SIRFSOC_SPI_RX_IO_DMA_INT_EN	BIT(4)
  #define SIRFSOC_SPI_TX_IO_DMA_INT_EN	BIT(5)
  #define SIRFSOC_SPI_RXFIFO_FULL_INT_EN	BIT(6)
  #define SIRFSOC_SPI_TXFIFO_EMPTY_INT_EN	BIT(7)
  #define SIRFSOC_SPI_RXFIFO_THD_INT_EN	BIT(8)
  #define SIRFSOC_SPI_TXFIFO_THD_INT_EN	BIT(9)
  #define SIRFSOC_SPI_FRM_END_INT_EN	BIT(10)
  
  /* Interrupt status */
  #define SIRFSOC_SPI_RX_DONE		BIT(0)
  #define SIRFSOC_SPI_TX_DONE		BIT(1)
  #define SIRFSOC_SPI_RX_OFLOW		BIT(2)
  #define SIRFSOC_SPI_TX_UFLOW		BIT(3)
  #define SIRFSOC_SPI_RX_IO_DMA		BIT(4)
  #define SIRFSOC_SPI_RX_FIFO_FULL	BIT(6)
  #define SIRFSOC_SPI_TXFIFO_EMPTY	BIT(7)
  #define SIRFSOC_SPI_RXFIFO_THD_REACH	BIT(8)
  #define SIRFSOC_SPI_TXFIFO_THD_REACH	BIT(9)
  #define SIRFSOC_SPI_FRM_END		BIT(10)
  
  /* TX RX enable */
  #define SIRFSOC_SPI_RX_EN		BIT(0)
  #define SIRFSOC_SPI_TX_EN		BIT(1)
  #define SIRFSOC_SPI_CMD_TX_EN		BIT(2)
  
  #define SIRFSOC_SPI_IO_MODE_SEL		BIT(0)
  #define SIRFSOC_SPI_RX_DMA_FLUSH	BIT(2)
  
  /* FIFO OPs */
  #define SIRFSOC_SPI_FIFO_RESET		BIT(0)
  #define SIRFSOC_SPI_FIFO_START		BIT(1)
  
  /* FIFO CTRL */
  #define SIRFSOC_SPI_FIFO_WIDTH_BYTE	(0 << 0)
  #define SIRFSOC_SPI_FIFO_WIDTH_WORD	(1 << 0)
  #define SIRFSOC_SPI_FIFO_WIDTH_DWORD	(2 << 0)
  /* USP related */
  #define SIRFSOC_USP_SYNC_MODE		BIT(0)
  #define SIRFSOC_USP_SLV_MODE		BIT(1)
  #define SIRFSOC_USP_LSB			BIT(4)
  #define SIRFSOC_USP_EN			BIT(5)
  #define SIRFSOC_USP_RXD_FALLING_EDGE	BIT(6)
  #define SIRFSOC_USP_TXD_FALLING_EDGE	BIT(7)
  #define SIRFSOC_USP_CS_HIGH_VALID	BIT(9)
  #define SIRFSOC_USP_SCLK_IDLE_STAT	BIT(11)
  #define SIRFSOC_USP_TFS_IO_MODE		BIT(14)
  #define SIRFSOC_USP_TFS_IO_INPUT	BIT(19)
  
  #define SIRFSOC_USP_RXD_DELAY_LEN_MASK	0xFF
  #define SIRFSOC_USP_TXD_DELAY_LEN_MASK	0xFF
  #define SIRFSOC_USP_RXD_DELAY_OFFSET	0
  #define SIRFSOC_USP_TXD_DELAY_OFFSET	8
  #define SIRFSOC_USP_RXD_DELAY_LEN	1
  #define SIRFSOC_USP_TXD_DELAY_LEN	1
  #define SIRFSOC_USP_CLK_DIVISOR_OFFSET	21
  #define SIRFSOC_USP_CLK_DIVISOR_MASK	0x3FF
  #define SIRFSOC_USP_CLK_10_11_MASK	0x3
  #define SIRFSOC_USP_CLK_10_11_OFFSET	30
  #define SIRFSOC_USP_CLK_12_15_MASK	0xF
  #define SIRFSOC_USP_CLK_12_15_OFFSET	24
  
  #define SIRFSOC_USP_TX_DATA_OFFSET	0
  #define SIRFSOC_USP_TX_SYNC_OFFSET	8
  #define SIRFSOC_USP_TX_FRAME_OFFSET	16
  #define SIRFSOC_USP_TX_SHIFTER_OFFSET	24
  
  #define SIRFSOC_USP_TX_DATA_MASK	0xFF
  #define SIRFSOC_USP_TX_SYNC_MASK	0xFF
  #define SIRFSOC_USP_TX_FRAME_MASK	0xFF
  #define SIRFSOC_USP_TX_SHIFTER_MASK	0x1F
  
  #define SIRFSOC_USP_RX_DATA_OFFSET	0
  #define SIRFSOC_USP_RX_FRAME_OFFSET	8
  #define SIRFSOC_USP_RX_SHIFTER_OFFSET	16
  
  #define SIRFSOC_USP_RX_DATA_MASK	0xFF
  #define SIRFSOC_USP_RX_FRAME_MASK	0xFF
  #define SIRFSOC_USP_RX_SHIFTER_MASK	0x1F
  #define SIRFSOC_USP_CS_HIGH_VALUE	BIT(1)
  
  #define SIRFSOC_SPI_FIFO_SC_OFFSET	0
  #define SIRFSOC_SPI_FIFO_LC_OFFSET	10
  #define SIRFSOC_SPI_FIFO_HC_OFFSET	20
  
  #define SIRFSOC_SPI_FIFO_FULL_MASK(s)	(1 << ((s)->fifo_full_offset))
  #define SIRFSOC_SPI_FIFO_EMPTY_MASK(s)	(1 << ((s)->fifo_full_offset + 1))
  #define SIRFSOC_SPI_FIFO_THD_MASK(s)	((s)->fifo_size - 1)
  #define SIRFSOC_SPI_FIFO_THD_OFFSET	2
  #define SIRFSOC_SPI_FIFO_LEVEL_CHK_MASK(s, val)	\
  	((val) & (s)->fifo_level_chk_mask)
  
  enum sirf_spi_type {
  	SIRF_REAL_SPI,
  	SIRF_USP_SPI_P2,
  	SIRF_USP_SPI_A7,
  };
  
  /*
   * only if the rx/tx buffer and transfer size are 4-bytes aligned, we use dma
   * due to the limitation of dma controller
   */
  
  #define ALIGNED(x) (!((u32)x & 0x3))
  #define IS_DMA_VALID(x) (x && ALIGNED(x->tx_buf) && ALIGNED(x->rx_buf) && \
  	ALIGNED(x->len) && (x->len < 2 * PAGE_SIZE))
  
  #define SIRFSOC_MAX_CMD_BYTES	4
  #define SIRFSOC_SPI_DEFAULT_FRQ 1000000
  
  struct sirf_spi_register {
  	/*SPI and USP-SPI common*/
  	u32 tx_rx_en;
  	u32 int_en;
  	u32 int_st;
  	u32 tx_dma_io_ctrl;
  	u32 tx_dma_io_len;
  	u32 txfifo_ctrl;
  	u32 txfifo_level_chk;
  	u32 txfifo_op;
  	u32 txfifo_st;
  	u32 txfifo_data;
  	u32 rx_dma_io_ctrl;
  	u32 rx_dma_io_len;
  	u32 rxfifo_ctrl;
  	u32 rxfifo_level_chk;
  	u32 rxfifo_op;
  	u32 rxfifo_st;
  	u32 rxfifo_data;
  	/*SPI self*/
  	u32 spi_ctrl;
  	u32 spi_cmd;
  	u32 spi_dummy_delay_ctrl;
  	/*USP-SPI self*/
  	u32 usp_mode1;
  	u32 usp_mode2;
  	u32 usp_tx_frame_ctrl;
  	u32 usp_rx_frame_ctrl;
  	u32 usp_pin_io_data;
  	u32 usp_risc_dsp_mode;
  	u32 usp_async_param_reg;
  	u32 usp_irda_x_mode_div;
  	u32 usp_sm_cfg;
  	u32 usp_int_en_clr;
  };
  
  static const struct sirf_spi_register real_spi_register = {
  	.tx_rx_en		= 0x8,
  	.int_en		= 0xc,
  	.int_st		= 0x10,
  	.tx_dma_io_ctrl	= 0x100,
  	.tx_dma_io_len	= 0x104,
  	.txfifo_ctrl	= 0x108,
  	.txfifo_level_chk	= 0x10c,
  	.txfifo_op		= 0x110,
  	.txfifo_st		= 0x114,
  	.txfifo_data	= 0x118,
  	.rx_dma_io_ctrl	= 0x120,
  	.rx_dma_io_len	= 0x124,
  	.rxfifo_ctrl	= 0x128,
  	.rxfifo_level_chk	= 0x12c,
  	.rxfifo_op		= 0x130,
  	.rxfifo_st		= 0x134,
  	.rxfifo_data	= 0x138,
  	.spi_ctrl		= 0x0,
  	.spi_cmd		= 0x4,
  	.spi_dummy_delay_ctrl	= 0x144,
  };
  
  static const struct sirf_spi_register usp_spi_register = {
  	.tx_rx_en		= 0x10,
  	.int_en		= 0x14,
  	.int_st		= 0x18,
  	.tx_dma_io_ctrl	= 0x100,
  	.tx_dma_io_len	= 0x104,
  	.txfifo_ctrl	= 0x108,
  	.txfifo_level_chk	= 0x10c,
  	.txfifo_op		= 0x110,
  	.txfifo_st		= 0x114,
  	.txfifo_data	= 0x118,
  	.rx_dma_io_ctrl	= 0x120,
  	.rx_dma_io_len	= 0x124,
  	.rxfifo_ctrl	= 0x128,
  	.rxfifo_level_chk	= 0x12c,
  	.rxfifo_op		= 0x130,
  	.rxfifo_st		= 0x134,
  	.rxfifo_data	= 0x138,
  	.usp_mode1		= 0x0,
  	.usp_mode2		= 0x4,
  	.usp_tx_frame_ctrl	= 0x8,
  	.usp_rx_frame_ctrl	= 0xc,
  	.usp_pin_io_data	= 0x1c,
  	.usp_risc_dsp_mode	= 0x20,
  	.usp_async_param_reg	= 0x24,
  	.usp_irda_x_mode_div	= 0x28,
  	.usp_sm_cfg		= 0x2c,
  	.usp_int_en_clr		= 0x140,
  };
  
  struct sirfsoc_spi {
  	struct spi_bitbang bitbang;
  	struct completion rx_done;
  	struct completion tx_done;
  
  	void __iomem *base;
  	u32 ctrl_freq;  /* SPI controller clock speed */
  	struct clk *clk;
  
  	/* rx & tx bufs from the spi_transfer */
  	const void *tx;
  	void *rx;
  
  	/* place received word into rx buffer */
  	void (*rx_word) (struct sirfsoc_spi *);
  	/* get word from tx buffer for sending */
  	void (*tx_word) (struct sirfsoc_spi *);
  
  	/* number of words left to be tranmitted/received */
  	unsigned int left_tx_word;
  	unsigned int left_rx_word;
  
  	/* rx & tx DMA channels */
  	struct dma_chan *rx_chan;
  	struct dma_chan *tx_chan;
  	dma_addr_t src_start;
  	dma_addr_t dst_start;
  	int word_width; /* in bytes */
  
  	/*
  	 * if tx size is not more than 4 and rx size is NULL, use
  	 * command model
  	 */
  	bool	tx_by_cmd;
  	bool	hw_cs;
  	enum sirf_spi_type type;
  	const struct sirf_spi_register *regs;
  	unsigned int fifo_size;
  	/* fifo empty offset is (fifo full offset + 1)*/
  	unsigned int fifo_full_offset;
  	/* fifo_level_chk_mask is (fifo_size/4 - 1) */
  	unsigned int fifo_level_chk_mask;
  	unsigned int dat_max_frm_len;
  };
  
  struct sirf_spi_comp_data {
  	const struct sirf_spi_register *regs;
  	enum sirf_spi_type type;
  	unsigned int dat_max_frm_len;
  	unsigned int fifo_size;
  	void (*hwinit)(struct sirfsoc_spi *sspi);
  };
  
  static void sirfsoc_usp_hwinit(struct sirfsoc_spi *sspi)
  {
  	/* reset USP and let USP can operate */
  	writel(readl(sspi->base + sspi->regs->usp_mode1) &
  		~SIRFSOC_USP_EN, sspi->base + sspi->regs->usp_mode1);
  	writel(readl(sspi->base + sspi->regs->usp_mode1) |
  		SIRFSOC_USP_EN, sspi->base + sspi->regs->usp_mode1);
  }
  
  static void spi_sirfsoc_rx_word_u8(struct sirfsoc_spi *sspi)
  {
  	u32 data;
  	u8 *rx = sspi->rx;
  
  	data = readl(sspi->base + sspi->regs->rxfifo_data);
  
  	if (rx) {
  		*rx++ = (u8) data;
  		sspi->rx = rx;
  	}
  
  	sspi->left_rx_word--;
  }
  
  static void spi_sirfsoc_tx_word_u8(struct sirfsoc_spi *sspi)
  {
  	u32 data = 0;
  	const u8 *tx = sspi->tx;
  
  	if (tx) {
  		data = *tx++;
  		sspi->tx = tx;
  	}
  	writel(data, sspi->base + sspi->regs->txfifo_data);
  	sspi->left_tx_word--;
  }
  
  static void spi_sirfsoc_rx_word_u16(struct sirfsoc_spi *sspi)
  {
  	u32 data;
  	u16 *rx = sspi->rx;
  
  	data = readl(sspi->base + sspi->regs->rxfifo_data);
  
  	if (rx) {
  		*rx++ = (u16) data;
  		sspi->rx = rx;
  	}
  
  	sspi->left_rx_word--;
  }
  
  static void spi_sirfsoc_tx_word_u16(struct sirfsoc_spi *sspi)
  {
  	u32 data = 0;
  	const u16 *tx = sspi->tx;
  
  	if (tx) {
  		data = *tx++;
  		sspi->tx = tx;
  	}
  
  	writel(data, sspi->base + sspi->regs->txfifo_data);
  	sspi->left_tx_word--;
  }
  
  static void spi_sirfsoc_rx_word_u32(struct sirfsoc_spi *sspi)
  {
  	u32 data;
  	u32 *rx = sspi->rx;
  
  	data = readl(sspi->base + sspi->regs->rxfifo_data);
  
  	if (rx) {
  		*rx++ = (u32) data;
  		sspi->rx = rx;
  	}
  
  	sspi->left_rx_word--;
  
  }
  
  static void spi_sirfsoc_tx_word_u32(struct sirfsoc_spi *sspi)
  {
  	u32 data = 0;
  	const u32 *tx = sspi->tx;
  
  	if (tx) {
  		data = *tx++;
  		sspi->tx = tx;
  	}
  
  	writel(data, sspi->base + sspi->regs->txfifo_data);
  	sspi->left_tx_word--;
  }
  
  static irqreturn_t spi_sirfsoc_irq(int irq, void *dev_id)
  {
  	struct sirfsoc_spi *sspi = dev_id;
  	u32 spi_stat;
  
  	spi_stat = readl(sspi->base + sspi->regs->int_st);
  	if (sspi->tx_by_cmd && sspi->type == SIRF_REAL_SPI
  		&& (spi_stat & SIRFSOC_SPI_FRM_END)) {
  		complete(&sspi->tx_done);
  		writel(0x0, sspi->base + sspi->regs->int_en);
  		writel(readl(sspi->base + sspi->regs->int_st),
  				sspi->base + sspi->regs->int_st);
  		return IRQ_HANDLED;
  	}
  	/* Error Conditions */
  	if (spi_stat & SIRFSOC_SPI_RX_OFLOW ||
  			spi_stat & SIRFSOC_SPI_TX_UFLOW) {
  		complete(&sspi->tx_done);
  		complete(&sspi->rx_done);
  		switch (sspi->type) {
  		case SIRF_REAL_SPI:
  		case SIRF_USP_SPI_P2:
  			writel(0x0, sspi->base + sspi->regs->int_en);
  			break;
  		case SIRF_USP_SPI_A7:
  			writel(~0UL, sspi->base + sspi->regs->usp_int_en_clr);
  			break;
  		}
  		writel(readl(sspi->base + sspi->regs->int_st),
  				sspi->base + sspi->regs->int_st);
  		return IRQ_HANDLED;
  	}
  	if (spi_stat & SIRFSOC_SPI_TXFIFO_EMPTY)
  		complete(&sspi->tx_done);
  	while (!(readl(sspi->base + sspi->regs->int_st) &
  		SIRFSOC_SPI_RX_IO_DMA))
  		cpu_relax();
  	complete(&sspi->rx_done);
  	switch (sspi->type) {
  	case SIRF_REAL_SPI:
  	case SIRF_USP_SPI_P2:
  		writel(0x0, sspi->base + sspi->regs->int_en);
  		break;
  	case SIRF_USP_SPI_A7:
  		writel(~0UL, sspi->base + sspi->regs->usp_int_en_clr);
  		break;
  	}
  	writel(readl(sspi->base + sspi->regs->int_st),
  			sspi->base + sspi->regs->int_st);
  
  	return IRQ_HANDLED;
  }
  
  static void spi_sirfsoc_dma_fini_callback(void *data)
  {
  	struct completion *dma_complete = data;
  
  	complete(dma_complete);
  }
  
  static void spi_sirfsoc_cmd_transfer(struct spi_device *spi,
  	struct spi_transfer *t)
  {
  	struct sirfsoc_spi *sspi;
  	int timeout = t->len * 10;
  	u32 cmd;
  
  	sspi = spi_master_get_devdata(spi->master);
  	writel(SIRFSOC_SPI_FIFO_RESET, sspi->base + sspi->regs->txfifo_op);
  	writel(SIRFSOC_SPI_FIFO_START, sspi->base + sspi->regs->txfifo_op);
  	memcpy(&cmd, sspi->tx, t->len);
  	if (sspi->word_width == 1 && !(spi->mode & SPI_LSB_FIRST))
  		cmd = cpu_to_be32(cmd) >>
  			((SIRFSOC_MAX_CMD_BYTES - t->len) * 8);
  	if (sspi->word_width == 2 && t->len == 4 &&
  			(!(spi->mode & SPI_LSB_FIRST)))
  		cmd = ((cmd & 0xffff) << 16) | (cmd >> 16);
  	writel(cmd, sspi->base + sspi->regs->spi_cmd);
  	writel(SIRFSOC_SPI_FRM_END_INT_EN,
  		sspi->base + sspi->regs->int_en);
  	writel(SIRFSOC_SPI_CMD_TX_EN,
  		sspi->base + sspi->regs->tx_rx_en);
  	if (wait_for_completion_timeout(&sspi->tx_done, timeout) == 0) {
  		dev_err(&spi->dev, "cmd transfer timeout
  ");
  		return;
  	}
  	sspi->left_rx_word -= t->len;
  }
  
  static void spi_sirfsoc_dma_transfer(struct spi_device *spi,
  	struct spi_transfer *t)
  {
  	struct sirfsoc_spi *sspi;
  	struct dma_async_tx_descriptor *rx_desc, *tx_desc;
  	int timeout = t->len * 10;
  
  	sspi = spi_master_get_devdata(spi->master);
  	writel(SIRFSOC_SPI_FIFO_RESET, sspi->base + sspi->regs->rxfifo_op);
  	writel(SIRFSOC_SPI_FIFO_RESET, sspi->base + sspi->regs->txfifo_op);
  	switch (sspi->type) {
  	case SIRF_REAL_SPI:
  		writel(SIRFSOC_SPI_FIFO_START,
  			sspi->base + sspi->regs->rxfifo_op);
  		writel(SIRFSOC_SPI_FIFO_START,
  			sspi->base + sspi->regs->txfifo_op);
  		writel(0, sspi->base + sspi->regs->int_en);
  		break;
  	case SIRF_USP_SPI_P2:
  		writel(0x0, sspi->base + sspi->regs->rxfifo_op);
  		writel(0x0, sspi->base + sspi->regs->txfifo_op);
  		writel(0, sspi->base + sspi->regs->int_en);
  		break;
  	case SIRF_USP_SPI_A7:
  		writel(0x0, sspi->base + sspi->regs->rxfifo_op);
  		writel(0x0, sspi->base + sspi->regs->txfifo_op);
  		writel(~0UL, sspi->base + sspi->regs->usp_int_en_clr);
  		break;
  	}
  	writel(readl(sspi->base + sspi->regs->int_st),
  		sspi->base + sspi->regs->int_st);
  	if (sspi->left_tx_word < sspi->dat_max_frm_len) {
  		switch (sspi->type) {
  		case SIRF_REAL_SPI:
  			writel(readl(sspi->base + sspi->regs->spi_ctrl) |
  				SIRFSOC_SPI_ENA_AUTO_CLR |
  				SIRFSOC_SPI_MUL_DAT_MODE,
  				sspi->base + sspi->regs->spi_ctrl);
  			writel(sspi->left_tx_word - 1,
  				sspi->base + sspi->regs->tx_dma_io_len);
  			writel(sspi->left_tx_word - 1,
  				sspi->base + sspi->regs->rx_dma_io_len);
  			break;
  		case SIRF_USP_SPI_P2:
  		case SIRF_USP_SPI_A7:
  			/*USP simulate SPI, tx/rx_dma_io_len indicates bytes*/
  			writel(sspi->left_tx_word * sspi->word_width,
  				sspi->base + sspi->regs->tx_dma_io_len);
  			writel(sspi->left_tx_word * sspi->word_width,
  				sspi->base + sspi->regs->rx_dma_io_len);
  			break;
  		}
  	} else {
  		if (sspi->type == SIRF_REAL_SPI)
  			writel(readl(sspi->base + sspi->regs->spi_ctrl),
  				sspi->base + sspi->regs->spi_ctrl);
  		writel(0, sspi->base + sspi->regs->tx_dma_io_len);
  		writel(0, sspi->base + sspi->regs->rx_dma_io_len);
  	}
  	sspi->dst_start = dma_map_single(&spi->dev, sspi->rx, t->len,
  					(t->tx_buf != t->rx_buf) ?
  					DMA_FROM_DEVICE : DMA_BIDIRECTIONAL);
  	rx_desc = dmaengine_prep_slave_single(sspi->rx_chan,
  		sspi->dst_start, t->len, DMA_DEV_TO_MEM,
  		DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
  	rx_desc->callback = spi_sirfsoc_dma_fini_callback;
  	rx_desc->callback_param = &sspi->rx_done;
  
  	sspi->src_start = dma_map_single(&spi->dev, (void *)sspi->tx, t->len,
  					(t->tx_buf != t->rx_buf) ?
  					DMA_TO_DEVICE : DMA_BIDIRECTIONAL);
  	tx_desc = dmaengine_prep_slave_single(sspi->tx_chan,
  		sspi->src_start, t->len, DMA_MEM_TO_DEV,
  		DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
  	tx_desc->callback = spi_sirfsoc_dma_fini_callback;
  	tx_desc->callback_param = &sspi->tx_done;
  
  	dmaengine_submit(tx_desc);
  	dmaengine_submit(rx_desc);
  	dma_async_issue_pending(sspi->tx_chan);
  	dma_async_issue_pending(sspi->rx_chan);
  	writel(SIRFSOC_SPI_RX_EN | SIRFSOC_SPI_TX_EN,
  			sspi->base + sspi->regs->tx_rx_en);
  	if (sspi->type == SIRF_USP_SPI_P2 ||
  		sspi->type == SIRF_USP_SPI_A7) {
  		writel(SIRFSOC_SPI_FIFO_START,
  			sspi->base + sspi->regs->rxfifo_op);
  		writel(SIRFSOC_SPI_FIFO_START,
  			sspi->base + sspi->regs->txfifo_op);
  	}
  	if (wait_for_completion_timeout(&sspi->rx_done, timeout) == 0) {
  		dev_err(&spi->dev, "transfer timeout
  ");
  		dmaengine_terminate_all(sspi->rx_chan);
  	} else
  		sspi->left_rx_word = 0;
  	/*
  	 * we only wait tx-done event if transferring by DMA. for PIO,
  	 * we get rx data by writing tx data, so if rx is done, tx has
  	 * done earlier
  	 */
  	if (wait_for_completion_timeout(&sspi->tx_done, timeout) == 0) {
  		dev_err(&spi->dev, "transfer timeout
  ");
  		if (sspi->type == SIRF_USP_SPI_P2 ||
  			sspi->type == SIRF_USP_SPI_A7)
  			writel(0, sspi->base + sspi->regs->tx_rx_en);
  		dmaengine_terminate_all(sspi->tx_chan);
  	}
  	dma_unmap_single(&spi->dev, sspi->src_start, t->len, DMA_TO_DEVICE);
  	dma_unmap_single(&spi->dev, sspi->dst_start, t->len, DMA_FROM_DEVICE);
  	/* TX, RX FIFO stop */
  	writel(0, sspi->base + sspi->regs->rxfifo_op);
  	writel(0, sspi->base + sspi->regs->txfifo_op);
  	if (sspi->left_tx_word >= sspi->dat_max_frm_len)
  		writel(0, sspi->base + sspi->regs->tx_rx_en);
  	if (sspi->type == SIRF_USP_SPI_P2 ||
  		sspi->type == SIRF_USP_SPI_A7)
  		writel(0, sspi->base + sspi->regs->tx_rx_en);
  }
  
  static void spi_sirfsoc_pio_transfer(struct spi_device *spi,
  		struct spi_transfer *t)
  {
  	struct sirfsoc_spi *sspi;
  	int timeout = t->len * 10;
  	unsigned int data_units;
  
  	sspi = spi_master_get_devdata(spi->master);
  	do {
  		writel(SIRFSOC_SPI_FIFO_RESET,
  			sspi->base + sspi->regs->rxfifo_op);
  		writel(SIRFSOC_SPI_FIFO_RESET,
  			sspi->base + sspi->regs->txfifo_op);
  		switch (sspi->type) {
  		case SIRF_USP_SPI_P2:
  			writel(0x0, sspi->base + sspi->regs->rxfifo_op);
  			writel(0x0, sspi->base + sspi->regs->txfifo_op);
  			writel(0, sspi->base + sspi->regs->int_en);
  			writel(readl(sspi->base + sspi->regs->int_st),
  				sspi->base + sspi->regs->int_st);
  			writel(min((sspi->left_tx_word * sspi->word_width),
  				sspi->fifo_size),
  				sspi->base + sspi->regs->tx_dma_io_len);
  			writel(min((sspi->left_rx_word * sspi->word_width),
  				sspi->fifo_size),
  				sspi->base + sspi->regs->rx_dma_io_len);
  			break;
  		case SIRF_USP_SPI_A7:
  			writel(0x0, sspi->base + sspi->regs->rxfifo_op);
  			writel(0x0, sspi->base + sspi->regs->txfifo_op);
  			writel(~0UL, sspi->base + sspi->regs->usp_int_en_clr);
  			writel(readl(sspi->base + sspi->regs->int_st),
  				sspi->base + sspi->regs->int_st);
  			writel(min((sspi->left_tx_word * sspi->word_width),
  				sspi->fifo_size),
  				sspi->base + sspi->regs->tx_dma_io_len);
  			writel(min((sspi->left_rx_word * sspi->word_width),
  				sspi->fifo_size),
  				sspi->base + sspi->regs->rx_dma_io_len);
  			break;
  		case SIRF_REAL_SPI:
  			writel(SIRFSOC_SPI_FIFO_START,
  				sspi->base + sspi->regs->rxfifo_op);
  			writel(SIRFSOC_SPI_FIFO_START,
  				sspi->base + sspi->regs->txfifo_op);
  			writel(0, sspi->base + sspi->regs->int_en);
  			writel(readl(sspi->base + sspi->regs->int_st),
  				sspi->base + sspi->regs->int_st);
  			writel(readl(sspi->base + sspi->regs->spi_ctrl) |
  				SIRFSOC_SPI_MUL_DAT_MODE |
  				SIRFSOC_SPI_ENA_AUTO_CLR,
  				sspi->base + sspi->regs->spi_ctrl);
  			data_units = sspi->fifo_size / sspi->word_width;
  			writel(min(sspi->left_tx_word, data_units) - 1,
  				sspi->base + sspi->regs->tx_dma_io_len);
  			writel(min(sspi->left_rx_word, data_units) - 1,
  				sspi->base + sspi->regs->rx_dma_io_len);
  			break;
  		}
  		while (!((readl(sspi->base + sspi->regs->txfifo_st)
  			& SIRFSOC_SPI_FIFO_FULL_MASK(sspi))) &&
  			sspi->left_tx_word)
  			sspi->tx_word(sspi);
  		writel(SIRFSOC_SPI_TXFIFO_EMPTY_INT_EN |
  			SIRFSOC_SPI_TX_UFLOW_INT_EN |
  			SIRFSOC_SPI_RX_OFLOW_INT_EN |
  			SIRFSOC_SPI_RX_IO_DMA_INT_EN,
  			sspi->base + sspi->regs->int_en);
  		writel(SIRFSOC_SPI_RX_EN | SIRFSOC_SPI_TX_EN,
  			sspi->base + sspi->regs->tx_rx_en);
  		if (sspi->type == SIRF_USP_SPI_P2 ||
  			sspi->type == SIRF_USP_SPI_A7) {
  			writel(SIRFSOC_SPI_FIFO_START,
  				sspi->base + sspi->regs->rxfifo_op);
  			writel(SIRFSOC_SPI_FIFO_START,
  				sspi->base + sspi->regs->txfifo_op);
  		}
  		if (!wait_for_completion_timeout(&sspi->tx_done, timeout) ||
  			!wait_for_completion_timeout(&sspi->rx_done, timeout)) {
  			dev_err(&spi->dev, "transfer timeout
  ");
  			if (sspi->type == SIRF_USP_SPI_P2 ||
  				sspi->type == SIRF_USP_SPI_A7)
  				writel(0, sspi->base + sspi->regs->tx_rx_en);
  			break;
  		}
  		while (!((readl(sspi->base + sspi->regs->rxfifo_st)
  			& SIRFSOC_SPI_FIFO_EMPTY_MASK(sspi))) &&
  			sspi->left_rx_word)
  			sspi->rx_word(sspi);
  		if (sspi->type == SIRF_USP_SPI_P2 ||
  			sspi->type == SIRF_USP_SPI_A7)
  			writel(0, sspi->base + sspi->regs->tx_rx_en);
  		writel(0, sspi->base + sspi->regs->rxfifo_op);
  		writel(0, sspi->base + sspi->regs->txfifo_op);
  	} while (sspi->left_tx_word != 0 || sspi->left_rx_word != 0);
  }
  
  static int spi_sirfsoc_transfer(struct spi_device *spi, struct spi_transfer *t)
  {
  	struct sirfsoc_spi *sspi;
  
  	sspi = spi_master_get_devdata(spi->master);
  	sspi->tx = t->tx_buf;
  	sspi->rx = t->rx_buf;
  	sspi->left_tx_word = sspi->left_rx_word = t->len / sspi->word_width;
  	reinit_completion(&sspi->rx_done);
  	reinit_completion(&sspi->tx_done);
  	/*
  	 * in the transfer, if transfer data using command register with rx_buf
  	 * null, just fill command data into command register and wait for its
  	 * completion.
  	 */
  	if (sspi->type == SIRF_REAL_SPI && sspi->tx_by_cmd)
  		spi_sirfsoc_cmd_transfer(spi, t);
  	else if (IS_DMA_VALID(t))
  		spi_sirfsoc_dma_transfer(spi, t);
  	else
  		spi_sirfsoc_pio_transfer(spi, t);
  
  	return t->len - sspi->left_rx_word * sspi->word_width;
  }
  
  static void spi_sirfsoc_chipselect(struct spi_device *spi, int value)
  {
  	struct sirfsoc_spi *sspi = spi_master_get_devdata(spi->master);
  
  	if (sspi->hw_cs) {
  		u32 regval;
  
  		switch (sspi->type) {
  		case SIRF_REAL_SPI:
  			regval = readl(sspi->base + sspi->regs->spi_ctrl);
  			switch (value) {
  			case BITBANG_CS_ACTIVE:
  				if (spi->mode & SPI_CS_HIGH)
  					regval |= SIRFSOC_SPI_CS_IO_OUT;
  				else
  					regval &= ~SIRFSOC_SPI_CS_IO_OUT;
  				break;
  			case BITBANG_CS_INACTIVE:
  				if (spi->mode & SPI_CS_HIGH)
  					regval &= ~SIRFSOC_SPI_CS_IO_OUT;
  				else
  					regval |= SIRFSOC_SPI_CS_IO_OUT;
  				break;
  			}
  			writel(regval, sspi->base + sspi->regs->spi_ctrl);
  			break;
  		case SIRF_USP_SPI_P2:
  		case SIRF_USP_SPI_A7:
  			regval = readl(sspi->base +
  					sspi->regs->usp_pin_io_data);
  			switch (value) {
  			case BITBANG_CS_ACTIVE:
  				if (spi->mode & SPI_CS_HIGH)
  					regval |= SIRFSOC_USP_CS_HIGH_VALUE;
  				else
  					regval &= ~(SIRFSOC_USP_CS_HIGH_VALUE);
  				break;
  			case BITBANG_CS_INACTIVE:
  				if (spi->mode & SPI_CS_HIGH)
  					regval &= ~(SIRFSOC_USP_CS_HIGH_VALUE);
  				else
  					regval |= SIRFSOC_USP_CS_HIGH_VALUE;
  				break;
  			}
  			writel(regval,
  				sspi->base + sspi->regs->usp_pin_io_data);
  			break;
  		}
  	} else {
  		switch (value) {
  		case BITBANG_CS_ACTIVE:
  			gpio_direction_output(spi->cs_gpio,
  					spi->mode & SPI_CS_HIGH ? 1 : 0);
  			break;
  		case BITBANG_CS_INACTIVE:
  			gpio_direction_output(spi->cs_gpio,
  					spi->mode & SPI_CS_HIGH ? 0 : 1);
  			break;
  		}
  	}
  }
  
  static int spi_sirfsoc_config_mode(struct spi_device *spi)
  {
  	struct sirfsoc_spi *sspi;
  	u32 regval, usp_mode1;
  
  	sspi = spi_master_get_devdata(spi->master);
  	regval = readl(sspi->base + sspi->regs->spi_ctrl);
  	usp_mode1 = readl(sspi->base + sspi->regs->usp_mode1);
  	if (!(spi->mode & SPI_CS_HIGH)) {
  		regval |= SIRFSOC_SPI_CS_IDLE_STAT;
  		usp_mode1 &= ~SIRFSOC_USP_CS_HIGH_VALID;
  	} else {
  		regval &= ~SIRFSOC_SPI_CS_IDLE_STAT;
  		usp_mode1 |= SIRFSOC_USP_CS_HIGH_VALID;
  	}
  	if (!(spi->mode & SPI_LSB_FIRST)) {
  		regval |= SIRFSOC_SPI_TRAN_MSB;
  		usp_mode1 &= ~SIRFSOC_USP_LSB;
  	} else {
  		regval &= ~SIRFSOC_SPI_TRAN_MSB;
  		usp_mode1 |= SIRFSOC_USP_LSB;
  	}
  	if (spi->mode & SPI_CPOL) {
  		regval |= SIRFSOC_SPI_CLK_IDLE_STAT;
  		usp_mode1 |= SIRFSOC_USP_SCLK_IDLE_STAT;
  	} else {
  		regval &= ~SIRFSOC_SPI_CLK_IDLE_STAT;
  		usp_mode1 &= ~SIRFSOC_USP_SCLK_IDLE_STAT;
  	}
  	/*
  	 * Data should be driven at least 1/2 cycle before the fetch edge
  	 * to make sure that data gets stable at the fetch edge.
  	 */
  	if (((spi->mode & SPI_CPOL) && (spi->mode & SPI_CPHA)) ||
  	    (!(spi->mode & SPI_CPOL) && !(spi->mode & SPI_CPHA))) {
  		regval &= ~SIRFSOC_SPI_DRV_POS_EDGE;
  		usp_mode1 |= (SIRFSOC_USP_TXD_FALLING_EDGE |
  				SIRFSOC_USP_RXD_FALLING_EDGE);
  	} else {
  		regval |= SIRFSOC_SPI_DRV_POS_EDGE;
  		usp_mode1 &= ~(SIRFSOC_USP_RXD_FALLING_EDGE |
  				SIRFSOC_USP_TXD_FALLING_EDGE);
  	}
  	writel((SIRFSOC_SPI_FIFO_LEVEL_CHK_MASK(sspi, sspi->fifo_size - 2) <<
  		SIRFSOC_SPI_FIFO_SC_OFFSET) |
  		(SIRFSOC_SPI_FIFO_LEVEL_CHK_MASK(sspi, sspi->fifo_size / 2) <<
  		SIRFSOC_SPI_FIFO_LC_OFFSET) |
  		(SIRFSOC_SPI_FIFO_LEVEL_CHK_MASK(sspi, 2) <<
  		SIRFSOC_SPI_FIFO_HC_OFFSET),
  		sspi->base + sspi->regs->txfifo_level_chk);
  	writel((SIRFSOC_SPI_FIFO_LEVEL_CHK_MASK(sspi, 2) <<
  		SIRFSOC_SPI_FIFO_SC_OFFSET) |
  		(SIRFSOC_SPI_FIFO_LEVEL_CHK_MASK(sspi, sspi->fifo_size / 2) <<
  		SIRFSOC_SPI_FIFO_LC_OFFSET) |
  		(SIRFSOC_SPI_FIFO_LEVEL_CHK_MASK(sspi, sspi->fifo_size - 2) <<
  		SIRFSOC_SPI_FIFO_HC_OFFSET),
  		sspi->base + sspi->regs->rxfifo_level_chk);
  	/*
  	 * it should never set to hardware cs mode because in hardware cs mode,
  	 * cs signal can't controlled by driver.
  	 */
  	switch (sspi->type) {
  	case SIRF_REAL_SPI:
  		regval |= SIRFSOC_SPI_CS_IO_MODE;
  		writel(regval, sspi->base + sspi->regs->spi_ctrl);
  		break;
  	case SIRF_USP_SPI_P2:
  	case SIRF_USP_SPI_A7:
  		usp_mode1 |= SIRFSOC_USP_SYNC_MODE;
  		usp_mode1 |= SIRFSOC_USP_TFS_IO_MODE;
  		usp_mode1 &= ~SIRFSOC_USP_TFS_IO_INPUT;
  		writel(usp_mode1, sspi->base + sspi->regs->usp_mode1);
  		break;
  	}
  
  	return 0;
  }
  
  static int
  spi_sirfsoc_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
  {
  	struct sirfsoc_spi *sspi;
  	u8 bits_per_word = 0;
  	int hz = 0;
  	u32 regval, txfifo_ctrl, rxfifo_ctrl, tx_frm_ctl, rx_frm_ctl, usp_mode2;
  
  	sspi = spi_master_get_devdata(spi->master);
  
  	bits_per_word = (t) ? t->bits_per_word : spi->bits_per_word;
  	hz = t && t->speed_hz ? t->speed_hz : spi->max_speed_hz;
  
  	usp_mode2 = regval = (sspi->ctrl_freq / (2 * hz)) - 1;
  	if (regval > 0xFFFF || regval < 0) {
  		dev_err(&spi->dev, "Speed %d not supported
  ", hz);
  		return -EINVAL;
  	}
  	switch (bits_per_word) {
  	case 8:
  		regval |= SIRFSOC_SPI_TRAN_DAT_FORMAT_8;
  		sspi->rx_word = spi_sirfsoc_rx_word_u8;
  		sspi->tx_word = spi_sirfsoc_tx_word_u8;
  		break;
  	case 12:
  	case 16:
  		regval |= (bits_per_word ==  12) ?
  			SIRFSOC_SPI_TRAN_DAT_FORMAT_12 :
  			SIRFSOC_SPI_TRAN_DAT_FORMAT_16;
  		sspi->rx_word = spi_sirfsoc_rx_word_u16;
  		sspi->tx_word = spi_sirfsoc_tx_word_u16;
  		break;
  	case 32:
  		regval |= SIRFSOC_SPI_TRAN_DAT_FORMAT_32;
  		sspi->rx_word = spi_sirfsoc_rx_word_u32;
  		sspi->tx_word = spi_sirfsoc_tx_word_u32;
  		break;
  	default:
  		dev_err(&spi->dev, "bpw %d not supported
  ", bits_per_word);
  		return -EINVAL;
  	}
  	sspi->word_width = DIV_ROUND_UP(bits_per_word, 8);
  	txfifo_ctrl = (((sspi->fifo_size / 2) &
  			SIRFSOC_SPI_FIFO_THD_MASK(sspi))
  			<< SIRFSOC_SPI_FIFO_THD_OFFSET) |
  			(sspi->word_width >> 1);
  	rxfifo_ctrl = (((sspi->fifo_size / 2) &
  			SIRFSOC_SPI_FIFO_THD_MASK(sspi))
  			<< SIRFSOC_SPI_FIFO_THD_OFFSET) |
  			(sspi->word_width >> 1);
  	writel(txfifo_ctrl, sspi->base + sspi->regs->txfifo_ctrl);
  	writel(rxfifo_ctrl, sspi->base + sspi->regs->rxfifo_ctrl);
  	if (sspi->type == SIRF_USP_SPI_P2 ||
  		sspi->type == SIRF_USP_SPI_A7) {
  		tx_frm_ctl = 0;
  		tx_frm_ctl |= ((bits_per_word - 1) & SIRFSOC_USP_TX_DATA_MASK)
  				<< SIRFSOC_USP_TX_DATA_OFFSET;
  		tx_frm_ctl |= ((bits_per_word + 1 + SIRFSOC_USP_TXD_DELAY_LEN
  				- 1) & SIRFSOC_USP_TX_SYNC_MASK) <<
  				SIRFSOC_USP_TX_SYNC_OFFSET;
  		tx_frm_ctl |= ((bits_per_word + 1 + SIRFSOC_USP_TXD_DELAY_LEN
  				+ 2 - 1) & SIRFSOC_USP_TX_FRAME_MASK) <<
  				SIRFSOC_USP_TX_FRAME_OFFSET;
  		tx_frm_ctl |= ((bits_per_word - 1) &
  				SIRFSOC_USP_TX_SHIFTER_MASK) <<
  				SIRFSOC_USP_TX_SHIFTER_OFFSET;
  		rx_frm_ctl = 0;
  		rx_frm_ctl |= ((bits_per_word - 1) & SIRFSOC_USP_RX_DATA_MASK)
  				<< SIRFSOC_USP_RX_DATA_OFFSET;
  		rx_frm_ctl |= ((bits_per_word + 1 + SIRFSOC_USP_RXD_DELAY_LEN
  				+ 2 - 1) & SIRFSOC_USP_RX_FRAME_MASK) <<
  				SIRFSOC_USP_RX_FRAME_OFFSET;
  		rx_frm_ctl |= ((bits_per_word - 1)
  				& SIRFSOC_USP_RX_SHIFTER_MASK) <<
  				SIRFSOC_USP_RX_SHIFTER_OFFSET;
  		writel(tx_frm_ctl | (((usp_mode2 >> 10) &
  			SIRFSOC_USP_CLK_10_11_MASK) <<
  			SIRFSOC_USP_CLK_10_11_OFFSET),
  			sspi->base + sspi->regs->usp_tx_frame_ctrl);
  		writel(rx_frm_ctl | (((usp_mode2 >> 12) &
  			SIRFSOC_USP_CLK_12_15_MASK) <<
  			SIRFSOC_USP_CLK_12_15_OFFSET),
  			sspi->base + sspi->regs->usp_rx_frame_ctrl);
  		writel(readl(sspi->base + sspi->regs->usp_mode2) |
  			((usp_mode2 & SIRFSOC_USP_CLK_DIVISOR_MASK) <<
  			SIRFSOC_USP_CLK_DIVISOR_OFFSET) |
  			(SIRFSOC_USP_RXD_DELAY_LEN <<
  			 SIRFSOC_USP_RXD_DELAY_OFFSET) |
  			(SIRFSOC_USP_TXD_DELAY_LEN <<
  			 SIRFSOC_USP_TXD_DELAY_OFFSET),
  			sspi->base + sspi->regs->usp_mode2);
  	}
  	if (sspi->type == SIRF_REAL_SPI)
  		writel(regval, sspi->base + sspi->regs->spi_ctrl);
  	spi_sirfsoc_config_mode(spi);
  	if (sspi->type == SIRF_REAL_SPI) {
  		if (t && t->tx_buf && !t->rx_buf &&
  			(t->len <= SIRFSOC_MAX_CMD_BYTES)) {
  			sspi->tx_by_cmd = true;
  			writel(readl(sspi->base + sspi->regs->spi_ctrl) |
  				(SIRFSOC_SPI_CMD_BYTE_NUM((t->len - 1)) |
  				SIRFSOC_SPI_CMD_MODE),
  				sspi->base + sspi->regs->spi_ctrl);
  		} else {
  			sspi->tx_by_cmd = false;
  			writel(readl(sspi->base + sspi->regs->spi_ctrl) &
  				~SIRFSOC_SPI_CMD_MODE,
  				sspi->base + sspi->regs->spi_ctrl);
  		}
  	}
  	if (IS_DMA_VALID(t)) {
  		/* Enable DMA mode for RX, TX */
  		writel(0, sspi->base + sspi->regs->tx_dma_io_ctrl);
  		writel(SIRFSOC_SPI_RX_DMA_FLUSH,
  			sspi->base + sspi->regs->rx_dma_io_ctrl);
  	} else {
  		/* Enable IO mode for RX, TX */
  		writel(SIRFSOC_SPI_IO_MODE_SEL,
  			sspi->base + sspi->regs->tx_dma_io_ctrl);
  		writel(SIRFSOC_SPI_IO_MODE_SEL,
  			sspi->base + sspi->regs->rx_dma_io_ctrl);
  	}
  	return 0;
  }
  
  static int spi_sirfsoc_setup(struct spi_device *spi)
  {
  	struct sirfsoc_spi *sspi;
  	int ret = 0;
  
  	sspi = spi_master_get_devdata(spi->master);
  	if (spi->cs_gpio == -ENOENT)
  		sspi->hw_cs = true;
  	else {
  		sspi->hw_cs = false;
  		if (!spi_get_ctldata(spi)) {
  			void *cs = kmalloc(sizeof(int), GFP_KERNEL);
  			if (!cs) {
  				ret = -ENOMEM;
  				goto exit;
  			}
  			ret = gpio_is_valid(spi->cs_gpio);
  			if (!ret) {
  				dev_err(&spi->dev, "no valid gpio
  ");
  				ret = -ENOENT;
  				goto exit;
  			}
  			ret = gpio_request(spi->cs_gpio, DRIVER_NAME);
  			if (ret) {
  				dev_err(&spi->dev, "failed to request gpio
  ");
  				goto exit;
  			}
  			spi_set_ctldata(spi, cs);
  		}
  	}
  	spi_sirfsoc_config_mode(spi);
  	spi_sirfsoc_chipselect(spi, BITBANG_CS_INACTIVE);
  exit:
  	return ret;
  }
  
  static void spi_sirfsoc_cleanup(struct spi_device *spi)
  {
  	if (spi_get_ctldata(spi)) {
  		gpio_free(spi->cs_gpio);
  		kfree(spi_get_ctldata(spi));
  	}
  }
  
  static const struct sirf_spi_comp_data sirf_real_spi = {
  	.regs = &real_spi_register,
  	.type = SIRF_REAL_SPI,
  	.dat_max_frm_len = 64 * 1024,
  	.fifo_size = 256,
  };
  
  static const struct sirf_spi_comp_data sirf_usp_spi_p2 = {
  	.regs = &usp_spi_register,
  	.type = SIRF_USP_SPI_P2,
  	.dat_max_frm_len = 1024 * 1024,
  	.fifo_size = 128,
  	.hwinit = sirfsoc_usp_hwinit,
  };
  
  static const struct sirf_spi_comp_data sirf_usp_spi_a7 = {
  	.regs = &usp_spi_register,
  	.type = SIRF_USP_SPI_A7,
  	.dat_max_frm_len = 1024 * 1024,
  	.fifo_size = 512,
  	.hwinit = sirfsoc_usp_hwinit,
  };
  
  static const struct of_device_id spi_sirfsoc_of_match[] = {
  	{ .compatible = "sirf,prima2-spi", .data = &sirf_real_spi},
  	{ .compatible = "sirf,prima2-usp-spi", .data = &sirf_usp_spi_p2},
  	{ .compatible = "sirf,atlas7-usp-spi", .data = &sirf_usp_spi_a7},
  	{}
  };
  MODULE_DEVICE_TABLE(of, spi_sirfsoc_of_match);
  
  static int spi_sirfsoc_probe(struct platform_device *pdev)
  {
  	struct sirfsoc_spi *sspi;
  	struct spi_master *master;
  	struct resource *mem_res;
  	struct sirf_spi_comp_data *spi_comp_data;
  	int irq;
  	int ret;
  	const struct of_device_id *match;
  
  	ret = device_reset(&pdev->dev);
  	if (ret) {
  		dev_err(&pdev->dev, "SPI reset failed!
  ");
  		return ret;
  	}
  
  	master = spi_alloc_master(&pdev->dev, sizeof(*sspi));
  	if (!master) {
  		dev_err(&pdev->dev, "Unable to allocate SPI master
  ");
  		return -ENOMEM;
  	}
  	match = of_match_node(spi_sirfsoc_of_match, pdev->dev.of_node);
  	platform_set_drvdata(pdev, master);
  	sspi = spi_master_get_devdata(master);
  	sspi->fifo_full_offset = ilog2(sspi->fifo_size);
  	spi_comp_data = (struct sirf_spi_comp_data *)match->data;
  	sspi->regs = spi_comp_data->regs;
  	sspi->type = spi_comp_data->type;
  	sspi->fifo_level_chk_mask = (sspi->fifo_size / 4) - 1;
  	sspi->dat_max_frm_len = spi_comp_data->dat_max_frm_len;
  	sspi->fifo_size = spi_comp_data->fifo_size;
  	mem_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	sspi->base = devm_ioremap_resource(&pdev->dev, mem_res);
  	if (IS_ERR(sspi->base)) {
  		ret = PTR_ERR(sspi->base);
  		goto free_master;
  	}
  	irq = platform_get_irq(pdev, 0);
  	if (irq < 0) {
  		ret = -ENXIO;
  		goto free_master;
  	}
  	ret = devm_request_irq(&pdev->dev, irq, spi_sirfsoc_irq, 0,
  				DRIVER_NAME, sspi);
  	if (ret)
  		goto free_master;
  
  	sspi->bitbang.master = master;
  	sspi->bitbang.chipselect = spi_sirfsoc_chipselect;
  	sspi->bitbang.setup_transfer = spi_sirfsoc_setup_transfer;
  	sspi->bitbang.txrx_bufs = spi_sirfsoc_transfer;
  	sspi->bitbang.master->setup = spi_sirfsoc_setup;
  	sspi->bitbang.master->cleanup = spi_sirfsoc_cleanup;
  	master->bus_num = pdev->id;
  	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LSB_FIRST | SPI_CS_HIGH;
  	master->bits_per_word_mask = SPI_BPW_MASK(8) | SPI_BPW_MASK(12) |
  					SPI_BPW_MASK(16) | SPI_BPW_MASK(32);
  	master->max_speed_hz = SIRFSOC_SPI_DEFAULT_FRQ;
  	master->flags = SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX;
  	sspi->bitbang.master->dev.of_node = pdev->dev.of_node;
  
  	/* request DMA channels */
  	sspi->rx_chan = dma_request_slave_channel(&pdev->dev, "rx");
  	if (!sspi->rx_chan) {
  		dev_err(&pdev->dev, "can not allocate rx dma channel
  ");
  		ret = -ENODEV;
  		goto free_master;
  	}
  	sspi->tx_chan = dma_request_slave_channel(&pdev->dev, "tx");
  	if (!sspi->tx_chan) {
  		dev_err(&pdev->dev, "can not allocate tx dma channel
  ");
  		ret = -ENODEV;
  		goto free_rx_dma;
  	}
  
  	sspi->clk = clk_get(&pdev->dev, NULL);
  	if (IS_ERR(sspi->clk)) {
  		ret = PTR_ERR(sspi->clk);
  		goto free_tx_dma;
  	}
  	clk_prepare_enable(sspi->clk);
  	if (spi_comp_data->hwinit)
  		spi_comp_data->hwinit(sspi);
  	sspi->ctrl_freq = clk_get_rate(sspi->clk);
  
  	init_completion(&sspi->rx_done);
  	init_completion(&sspi->tx_done);
  
  	ret = spi_bitbang_start(&sspi->bitbang);
  	if (ret)
  		goto free_clk;
  	dev_info(&pdev->dev, "registerred, bus number = %d
  ", master->bus_num);
  
  	return 0;
  free_clk:
  	clk_disable_unprepare(sspi->clk);
  	clk_put(sspi->clk);
  free_tx_dma:
  	dma_release_channel(sspi->tx_chan);
  free_rx_dma:
  	dma_release_channel(sspi->rx_chan);
  free_master:
  	spi_master_put(master);
  
  	return ret;
  }
  
  static int  spi_sirfsoc_remove(struct platform_device *pdev)
  {
  	struct spi_master *master;
  	struct sirfsoc_spi *sspi;
  
  	master = platform_get_drvdata(pdev);
  	sspi = spi_master_get_devdata(master);
  	spi_bitbang_stop(&sspi->bitbang);
  	clk_disable_unprepare(sspi->clk);
  	clk_put(sspi->clk);
  	dma_release_channel(sspi->rx_chan);
  	dma_release_channel(sspi->tx_chan);
  	spi_master_put(master);
  	return 0;
  }
  
  #ifdef CONFIG_PM_SLEEP
  static int spi_sirfsoc_suspend(struct device *dev)
  {
  	struct spi_master *master = dev_get_drvdata(dev);
  	struct sirfsoc_spi *sspi = spi_master_get_devdata(master);
  	int ret;
  
  	ret = spi_master_suspend(master);
  	if (ret)
  		return ret;
  
  	clk_disable(sspi->clk);
  	return 0;
  }
  
  static int spi_sirfsoc_resume(struct device *dev)
  {
  	struct spi_master *master = dev_get_drvdata(dev);
  	struct sirfsoc_spi *sspi = spi_master_get_devdata(master);
  
  	clk_enable(sspi->clk);
  	writel(SIRFSOC_SPI_FIFO_RESET, sspi->base + sspi->regs->txfifo_op);
  	writel(SIRFSOC_SPI_FIFO_RESET, sspi->base + sspi->regs->rxfifo_op);
  	writel(SIRFSOC_SPI_FIFO_START, sspi->base + sspi->regs->txfifo_op);
  	writel(SIRFSOC_SPI_FIFO_START, sspi->base + sspi->regs->rxfifo_op);
  	return 0;
  }
  #endif
  
  static SIMPLE_DEV_PM_OPS(spi_sirfsoc_pm_ops, spi_sirfsoc_suspend,
  			 spi_sirfsoc_resume);
  
  static struct platform_driver spi_sirfsoc_driver = {
  	.driver = {
  		.name = DRIVER_NAME,
  		.pm     = &spi_sirfsoc_pm_ops,
  		.of_match_table = spi_sirfsoc_of_match,
  	},
  	.probe = spi_sirfsoc_probe,
  	.remove = spi_sirfsoc_remove,
  };
  module_platform_driver(spi_sirfsoc_driver);
  MODULE_DESCRIPTION("SiRF SoC SPI master driver");
  MODULE_AUTHOR("Zhiwu Song <Zhiwu.Song@csr.com>");
  MODULE_AUTHOR("Barry Song <Baohua.Song@csr.com>");
  MODULE_AUTHOR("Qipan Li <Qipan.Li@csr.com>");
  MODULE_LICENSE("GPL v2");