text: // SPDX-License-Identifier: GPL-2.0-only
  //
  // Copyright (C) 2020 NVIDIA CORPORATION.
  
  #include <linux/clk.h>
  #include <linux/completion.h>
  #include <linux/delay.h>
  #include <linux/dmaengine.h>
  #include <linux/dma-mapping.h>
  #include <linux/dmapool.h>
  #include <linux/err.h>
  #include <linux/interrupt.h>
  #include <linux/io.h>
  #include <linux/iopoll.h>
  #include <linux/kernel.h>
  #include <linux/kthread.h>
  #include <linux/module.h>
  #include <linux/platform_device.h>
  #include <linux/pm_runtime.h>
  #include <linux/of.h>
  #include <linux/of_device.h>
  #include <linux/reset.h>
  #include <linux/spi/spi.h>
  #include <linux/acpi.h>
  #include <linux/property.h>
  
  #define QSPI_COMMAND1				0x000
  #define QSPI_BIT_LENGTH(x)			(((x) & 0x1f) << 0)
  #define QSPI_PACKED				BIT(5)
  #define QSPI_INTERFACE_WIDTH_MASK		(0x03 << 7)
  #define QSPI_INTERFACE_WIDTH(x)			(((x) & 0x03) << 7)
  #define QSPI_INTERFACE_WIDTH_SINGLE		QSPI_INTERFACE_WIDTH(0)
  #define QSPI_INTERFACE_WIDTH_DUAL		QSPI_INTERFACE_WIDTH(1)
  #define QSPI_INTERFACE_WIDTH_QUAD		QSPI_INTERFACE_WIDTH(2)
  #define QSPI_SDR_DDR_SEL			BIT(9)
  #define QSPI_TX_EN				BIT(11)
  #define QSPI_RX_EN				BIT(12)
  #define QSPI_CS_SW_VAL				BIT(20)
  #define QSPI_CS_SW_HW				BIT(21)
  #define QSPI_CONTROL_MODE_0			(0 << 28)
  #define QSPI_CONTROL_MODE_3			(3 << 28)
  #define QSPI_CONTROL_MODE_MASK			(3 << 28)
  #define QSPI_M_S				BIT(30)
  #define QSPI_PIO				BIT(31)
  
  #define QSPI_COMMAND2				0x004
  #define QSPI_TX_TAP_DELAY(x)			(((x) & 0x3f) << 10)
  #define QSPI_RX_TAP_DELAY(x)			(((x) & 0xff) << 0)
  
  #define QSPI_CS_TIMING1				0x008
  #define QSPI_SETUP_HOLD(setup, hold)		(((setup) << 4) | (hold))
  
  #define QSPI_CS_TIMING2				0x00c
  #define CYCLES_BETWEEN_PACKETS_0(x)		(((x) & 0x1f) << 0)
  #define CS_ACTIVE_BETWEEN_PACKETS_0		BIT(5)
  
  #define QSPI_TRANS_STATUS			0x010
  #define QSPI_BLK_CNT(val)			(((val) >> 0) & 0xffff)
  #define QSPI_RDY				BIT(30)
  
  #define QSPI_FIFO_STATUS			0x014
  #define QSPI_RX_FIFO_EMPTY			BIT(0)
  #define QSPI_RX_FIFO_FULL			BIT(1)
  #define QSPI_TX_FIFO_EMPTY			BIT(2)
  #define QSPI_TX_FIFO_FULL			BIT(3)
  #define QSPI_RX_FIFO_UNF			BIT(4)
  #define QSPI_RX_FIFO_OVF			BIT(5)
  #define QSPI_TX_FIFO_UNF			BIT(6)
  #define QSPI_TX_FIFO_OVF			BIT(7)
  #define QSPI_ERR				BIT(8)
  #define QSPI_TX_FIFO_FLUSH			BIT(14)
  #define QSPI_RX_FIFO_FLUSH			BIT(15)
  #define QSPI_TX_FIFO_EMPTY_COUNT(val)		(((val) >> 16) & 0x7f)
  #define QSPI_RX_FIFO_FULL_COUNT(val)		(((val) >> 23) & 0x7f)
  
  #define QSPI_FIFO_ERROR				(QSPI_RX_FIFO_UNF | \
  						 QSPI_RX_FIFO_OVF | \
  						 QSPI_TX_FIFO_UNF | \
  						 QSPI_TX_FIFO_OVF)
  #define QSPI_FIFO_EMPTY				(QSPI_RX_FIFO_EMPTY | \
  						 QSPI_TX_FIFO_EMPTY)
  
  #define QSPI_TX_DATA				0x018
  #define QSPI_RX_DATA				0x01c
  
  #define QSPI_DMA_CTL				0x020
  #define QSPI_TX_TRIG(n)				(((n) & 0x3) << 15)
  #define QSPI_TX_TRIG_1				QSPI_TX_TRIG(0)
  #define QSPI_TX_TRIG_4				QSPI_TX_TRIG(1)
  #define QSPI_TX_TRIG_8				QSPI_TX_TRIG(2)
  #define QSPI_TX_TRIG_16				QSPI_TX_TRIG(3)
  
  #define QSPI_RX_TRIG(n)				(((n) & 0x3) << 19)
  #define QSPI_RX_TRIG_1				QSPI_RX_TRIG(0)
  #define QSPI_RX_TRIG_4				QSPI_RX_TRIG(1)
  #define QSPI_RX_TRIG_8				QSPI_RX_TRIG(2)
  #define QSPI_RX_TRIG_16				QSPI_RX_TRIG(3)
  
  #define QSPI_DMA_EN				BIT(31)
  
  #define QSPI_DMA_BLK				0x024
  #define QSPI_DMA_BLK_SET(x)			(((x) & 0xffff) << 0)
  
  #define QSPI_TX_FIFO				0x108
  #define QSPI_RX_FIFO				0x188
  
  #define QSPI_FIFO_DEPTH				64
  
  #define QSPI_INTR_MASK				0x18c
  #define QSPI_INTR_RX_FIFO_UNF_MASK		BIT(25)
  #define QSPI_INTR_RX_FIFO_OVF_MASK		BIT(26)
  #define QSPI_INTR_TX_FIFO_UNF_MASK		BIT(27)
  #define QSPI_INTR_TX_FIFO_OVF_MASK		BIT(28)
  #define QSPI_INTR_RDY_MASK			BIT(29)
  #define QSPI_INTR_RX_TX_FIFO_ERR		(QSPI_INTR_RX_FIFO_UNF_MASK | \
  						 QSPI_INTR_RX_FIFO_OVF_MASK | \
  						 QSPI_INTR_TX_FIFO_UNF_MASK | \
  						 QSPI_INTR_TX_FIFO_OVF_MASK)
  
  #define QSPI_MISC_REG                           0x194
  #define QSPI_NUM_DUMMY_CYCLE(x)			(((x) & 0xff) << 0)
  #define QSPI_DUMMY_CYCLES_MAX			0xff
  
  #define QSPI_CMB_SEQ_CMD			0x19c
  #define QSPI_COMMAND_VALUE_SET(X)		(((x) & 0xFF) << 0)
  
  #define QSPI_CMB_SEQ_CMD_CFG			0x1a0
  #define QSPI_COMMAND_X1_X2_X4(x)		(((x) & 0x3) << 13)
  #define QSPI_COMMAND_X1_X2_X4_MASK		(0x03 << 13)
  #define QSPI_COMMAND_SDR_DDR			BIT(12)
  #define QSPI_COMMAND_SIZE_SET(x)		(((x) & 0xFF) << 0)
  
  #define QSPI_GLOBAL_CONFIG			0X1a4
  #define QSPI_CMB_SEQ_EN				BIT(0)
  
  #define QSPI_CMB_SEQ_ADDR			0x1a8
  #define QSPI_ADDRESS_VALUE_SET(X)		(((x) & 0xFFFF) << 0)
  
  #define QSPI_CMB_SEQ_ADDR_CFG			0x1ac
  #define QSPI_ADDRESS_X1_X2_X4(x)		(((x) & 0x3) << 13)
  #define QSPI_ADDRESS_X1_X2_X4_MASK		(0x03 << 13)
  #define QSPI_ADDRESS_SDR_DDR			BIT(12)
  #define QSPI_ADDRESS_SIZE_SET(x)		(((x) & 0xFF) << 0)
  
  #define DATA_DIR_TX				BIT(0)
  #define DATA_DIR_RX				BIT(1)
  
  #define QSPI_DMA_TIMEOUT			(msecs_to_jiffies(1000))
  #define DEFAULT_QSPI_DMA_BUF_LEN		(64 * 1024)
  #define CMD_TRANSFER				0
  #define ADDR_TRANSFER				1
  #define DATA_TRANSFER				2
  
  struct tegra_qspi_soc_data {
  	bool has_dma;
  	bool cmb_xfer_capable;
  };
  
  struct tegra_qspi_client_data {
  	int tx_clk_tap_delay;
  	int rx_clk_tap_delay;
  };
  
  struct tegra_qspi {
  	struct device				*dev;
  	struct spi_master			*master;
  	/* lock to protect data accessed by irq */
  	spinlock_t				lock;
  
  	struct clk				*clk;
  	void __iomem				*base;
  	phys_addr_t				phys;
  	unsigned int				irq;
  
  	u32					cur_speed;
  	unsigned int				cur_pos;
  	unsigned int				words_per_32bit;
  	unsigned int				bytes_per_word;
  	unsigned int				curr_dma_words;
  	unsigned int				cur_direction;
  
  	unsigned int				cur_rx_pos;
  	unsigned int				cur_tx_pos;
  
  	unsigned int				dma_buf_size;
  	unsigned int				max_buf_size;
  	bool					is_curr_dma_xfer;
  
  	struct completion			rx_dma_complete;
  	struct completion			tx_dma_complete;
  
  	u32					tx_status;
  	u32					rx_status;
  	u32					status_reg;
  	bool					is_packed;
  	bool					use_dma;
  
  	u32					command1_reg;
  	u32					dma_control_reg;
  	u32					def_command1_reg;
  	u32					def_command2_reg;
  	u32					spi_cs_timing1;
  	u32					spi_cs_timing2;
  	u8					dummy_cycles;
  
  	struct completion			xfer_completion;
  	struct spi_transfer			*curr_xfer;
  
  	struct dma_chan				*rx_dma_chan;
  	u32					*rx_dma_buf;
  	dma_addr_t				rx_dma_phys;
  	struct dma_async_tx_descriptor		*rx_dma_desc;
  
  	struct dma_chan				*tx_dma_chan;
  	u32					*tx_dma_buf;
  	dma_addr_t				tx_dma_phys;
  	struct dma_async_tx_descriptor		*tx_dma_desc;
  	const struct tegra_qspi_soc_data	*soc_data;
  };
  
  static inline u32 tegra_qspi_readl(struct tegra_qspi *tqspi, unsigned long offset)
  {
  	return readl(tqspi->base + offset);
  }
  
  static inline void tegra_qspi_writel(struct tegra_qspi *tqspi, u32 value, unsigned long offset)
  {
  	writel(value, tqspi->base + offset);
  
  	/* read back register to make sure that register writes completed */
  	if (offset != QSPI_TX_FIFO)
  		readl(tqspi->base + QSPI_COMMAND1);
  }
  
  static void tegra_qspi_mask_clear_irq(struct tegra_qspi *tqspi)
  {
  	u32 value;
  
  	/* write 1 to clear status register */
  	value = tegra_qspi_readl(tqspi, QSPI_TRANS_STATUS);
  	tegra_qspi_writel(tqspi, value, QSPI_TRANS_STATUS);
  
  	value = tegra_qspi_readl(tqspi, QSPI_INTR_MASK);
  	if (!(value & QSPI_INTR_RDY_MASK)) {
  		value |= (QSPI_INTR_RDY_MASK | QSPI_INTR_RX_TX_FIFO_ERR);
  		tegra_qspi_writel(tqspi, value, QSPI_INTR_MASK);
  	}
  
  	/* clear fifo status error if any */
  	value = tegra_qspi_readl(tqspi, QSPI_FIFO_STATUS);
  	if (value & QSPI_ERR)
  		tegra_qspi_writel(tqspi, QSPI_ERR | QSPI_FIFO_ERROR, QSPI_FIFO_STATUS);
  }
  
  static unsigned int
  tegra_qspi_calculate_curr_xfer_param(struct tegra_qspi *tqspi, struct spi_transfer *t)
  {
  	unsigned int max_word, max_len, total_fifo_words;
  	unsigned int remain_len = t->len - tqspi->cur_pos;
  	unsigned int bits_per_word = t->bits_per_word;
  
  	tqspi->bytes_per_word = DIV_ROUND_UP(bits_per_word, 8);
  
  	/*
  	 * Tegra QSPI controller supports packed or unpacked mode transfers.
  	 * Packed mode is used for data transfers using 8, 16, or 32 bits per
  	 * word with a minimum transfer of 1 word and for all other transfers
  	 * unpacked mode will be used.
  	 */
  
  	if ((bits_per_word == 8 || bits_per_word == 16 ||
  	     bits_per_word == 32) && t->len > 3) {
  		tqspi->is_packed = true;
  		tqspi->words_per_32bit = 32 / bits_per_word;
  	} else {
  		tqspi->is_packed = false;
  		tqspi->words_per_32bit = 1;
  	}
  
  	if (tqspi->is_packed) {
  		max_len = min(remain_len, tqspi->max_buf_size);
  		tqspi->curr_dma_words = max_len / tqspi->bytes_per_word;
  		total_fifo_words = (max_len + 3) / 4;
  	} else {
  		max_word = (remain_len - 1) / tqspi->bytes_per_word + 1;
  		max_word = min(max_word, tqspi->max_buf_size / 4);
  		tqspi->curr_dma_words = max_word;
  		total_fifo_words = max_word;
  	}
  
  	return total_fifo_words;
  }
  
  static unsigned int
  tegra_qspi_fill_tx_fifo_from_client_txbuf(struct tegra_qspi *tqspi, struct spi_transfer *t)
  {
  	unsigned int written_words, fifo_words_left, count;
  	unsigned int len, tx_empty_count, max_n_32bit, i;
  	u8 *tx_buf = (u8 *)t->tx_buf + tqspi->cur_tx_pos;
  	u32 fifo_status;
  
  	fifo_status = tegra_qspi_readl(tqspi, QSPI_FIFO_STATUS);
  	tx_empty_count = QSPI_TX_FIFO_EMPTY_COUNT(fifo_status);
  
  	if (tqspi->is_packed) {
  		fifo_words_left = tx_empty_count * tqspi->words_per_32bit;
  		written_words = min(fifo_words_left, tqspi->curr_dma_words);
  		len = written_words * tqspi->bytes_per_word;
  		max_n_32bit = DIV_ROUND_UP(len, 4);
  		for (count = 0; count < max_n_32bit; count++) {
  			u32 x = 0;
  
  			for (i = 0; (i < 4) && len; i++, len--)
  				x |= (u32)(*tx_buf++) << (i * 8);
  			tegra_qspi_writel(tqspi, x, QSPI_TX_FIFO);
  		}
  
  		tqspi->cur_tx_pos += written_words * tqspi->bytes_per_word;
  	} else {
  		unsigned int write_bytes;
  		u8 bytes_per_word = tqspi->bytes_per_word;
  
  		max_n_32bit = min(tqspi->curr_dma_words, tx_empty_count);
  		written_words = max_n_32bit;
  		len = written_words * tqspi->bytes_per_word;
  		if (len > t->len - tqspi->cur_pos)
  			len = t->len - tqspi->cur_pos;
  		write_bytes = len;
  		for (count = 0; count < max_n_32bit; count++) {
  			u32 x = 0;
  
  			for (i = 0; len && (i < bytes_per_word); i++, len--)
  				x |= (u32)(*tx_buf++) << (i * 8);
  			tegra_qspi_writel(tqspi, x, QSPI_TX_FIFO);
  		}
  
  		tqspi->cur_tx_pos += write_bytes;
  	}
  
  	return written_words;
  }
  
  static unsigned int
  tegra_qspi_read_rx_fifo_to_client_rxbuf(struct tegra_qspi *tqspi, struct spi_transfer *t)
  {
  	u8 *rx_buf = (u8 *)t->rx_buf + tqspi->cur_rx_pos;
  	unsigned int len, rx_full_count, count, i;
  	unsigned int read_words = 0;
  	u32 fifo_status, x;
  
  	fifo_status = tegra_qspi_readl(tqspi, QSPI_FIFO_STATUS);
  	rx_full_count = QSPI_RX_FIFO_FULL_COUNT(fifo_status);
  	if (tqspi->is_packed) {
  		len = tqspi->curr_dma_words * tqspi->bytes_per_word;
  		for (count = 0; count < rx_full_count; count++) {
  			x = tegra_qspi_readl(tqspi, QSPI_RX_FIFO);
  
  			for (i = 0; len && (i < 4); i++, len--)
  				*rx_buf++ = (x >> i * 8) & 0xff;
  		}
  
  		read_words += tqspi->curr_dma_words;
  		tqspi->cur_rx_pos += tqspi->curr_dma_words * tqspi->bytes_per_word;
  	} else {
  		u32 rx_mask = ((u32)1 << t->bits_per_word) - 1;
  		u8 bytes_per_word = tqspi->bytes_per_word;
  		unsigned int read_bytes;
  
  		len = rx_full_count * bytes_per_word;
  		if (len > t->len - tqspi->cur_pos)
  			len = t->len - tqspi->cur_pos;
  		read_bytes = len;
  		for (count = 0; count < rx_full_count; count++) {
  			x = tegra_qspi_readl(tqspi, QSPI_RX_FIFO) & rx_mask;
  
  			for (i = 0; len && (i < bytes_per_word); i++, len--)
  				*rx_buf++ = (x >> (i * 8)) & 0xff;
  		}
  
  		read_words += rx_full_count;
  		tqspi->cur_rx_pos += read_bytes;
  	}
  
  	return read_words;
  }
  
  static void
  tegra_qspi_copy_client_txbuf_to_qspi_txbuf(struct tegra_qspi *tqspi, struct spi_transfer *t)
  {
  	dma_sync_single_for_cpu(tqspi->dev, tqspi->tx_dma_phys,
  				tqspi->dma_buf_size, DMA_TO_DEVICE);
  
  	/*
  	 * In packed mode, each word in FIFO may contain multiple packets
  	 * based on bits per word. So all bytes in each FIFO word are valid.
  	 *
  	 * In unpacked mode, each word in FIFO contains single packet and
  	 * based on bits per word any remaining bits in FIFO word will be
  	 * ignored by the hardware and are invalid bits.
  	 */
  	if (tqspi->is_packed) {
  		tqspi->cur_tx_pos += tqspi->curr_dma_words * tqspi->bytes_per_word;
  	} else {
  		u8 *tx_buf = (u8 *)t->tx_buf + tqspi->cur_tx_pos;
  		unsigned int i, count, consume, write_bytes;
  
  		/*
  		 * Fill tx_dma_buf to contain single packet in each word based
  		 * on bits per word from SPI core tx_buf.
  		 */
  		consume = tqspi->curr_dma_words * tqspi->bytes_per_word;
  		if (consume > t->len - tqspi->cur_pos)
  			consume = t->len - tqspi->cur_pos;
  		write_bytes = consume;
  		for (count = 0; count < tqspi->curr_dma_words; count++) {
  			u32 x = 0;
  
  			for (i = 0; consume && (i < tqspi->bytes_per_word); i++, consume--)
  				x |= (u32)(*tx_buf++) << (i * 8);
  			tqspi->tx_dma_buf[count] = x;
  		}
  
  		tqspi->cur_tx_pos += write_bytes;
  	}
  
  	dma_sync_single_for_device(tqspi->dev, tqspi->tx_dma_phys,
  				   tqspi->dma_buf_size, DMA_TO_DEVICE);
  }
  
  static void
  tegra_qspi_copy_qspi_rxbuf_to_client_rxbuf(struct tegra_qspi *tqspi, struct spi_transfer *t)
  {
  	dma_sync_single_for_cpu(tqspi->dev, tqspi->rx_dma_phys,
  				tqspi->dma_buf_size, DMA_FROM_DEVICE);
  
  	if (tqspi->is_packed) {
  		tqspi->cur_rx_pos += tqspi->curr_dma_words * tqspi->bytes_per_word;
  	} else {
  		unsigned char *rx_buf = t->rx_buf + tqspi->cur_rx_pos;
  		u32 rx_mask = ((u32)1 << t->bits_per_word) - 1;
  		unsigned int i, count, consume, read_bytes;
  
  		/*
  		 * Each FIFO word contains single data packet.
  		 * Skip invalid bits in each FIFO word based on bits per word
  		 * and align bytes while filling in SPI core rx_buf.
  		 */
  		consume = tqspi->curr_dma_words * tqspi->bytes_per_word;
  		if (consume > t->len - tqspi->cur_pos)
  			consume = t->len - tqspi->cur_pos;
  		read_bytes = consume;
  		for (count = 0; count < tqspi->curr_dma_words; count++) {
  			u32 x = tqspi->rx_dma_buf[count] & rx_mask;
  
  			for (i = 0; consume && (i < tqspi->bytes_per_word); i++, consume--)
  				*rx_buf++ = (x >> (i * 8)) & 0xff;
  		}
  
  		tqspi->cur_rx_pos += read_bytes;
  	}
  
  	dma_sync_single_for_device(tqspi->dev, tqspi->rx_dma_phys,
  				   tqspi->dma_buf_size, DMA_FROM_DEVICE);
  }
  
  static void tegra_qspi_dma_complete(void *args)
  {
  	struct completion *dma_complete = args;
  
  	complete(dma_complete);
  }
  
  static int tegra_qspi_start_tx_dma(struct tegra_qspi *tqspi, struct spi_transfer *t, int len)
  {
  	dma_addr_t tx_dma_phys;
  
  	reinit_completion(&tqspi->tx_dma_complete);
  
  	if (tqspi->is_packed)
  		tx_dma_phys = t->tx_dma;
  	else
  		tx_dma_phys = tqspi->tx_dma_phys;
  
  	tqspi->tx_dma_desc = dmaengine_prep_slave_single(tqspi->tx_dma_chan, tx_dma_phys,
  							 len, DMA_MEM_TO_DEV,
  							 DMA_PREP_INTERRUPT |  DMA_CTRL_ACK);
  
  	if (!tqspi->tx_dma_desc) {
  		dev_err(tqspi->dev, "Unable to get TX descriptor\n");
  		return -EIO;
  	}
  
  	tqspi->tx_dma_desc->callback = tegra_qspi_dma_complete;
  	tqspi->tx_dma_desc->callback_param = &tqspi->tx_dma_complete;
  	dmaengine_submit(tqspi->tx_dma_desc);
  	dma_async_issue_pending(tqspi->tx_dma_chan);
  
  	return 0;
  }
  
  static int tegra_qspi_start_rx_dma(struct tegra_qspi *tqspi, struct spi_transfer *t, int len)
  {
  	dma_addr_t rx_dma_phys;
  
  	reinit_completion(&tqspi->rx_dma_complete);
  
  	if (tqspi->is_packed)
  		rx_dma_phys = t->rx_dma;
  	else
  		rx_dma_phys = tqspi->rx_dma_phys;
  
  	tqspi->rx_dma_desc = dmaengine_prep_slave_single(tqspi->rx_dma_chan, rx_dma_phys,
  							 len, DMA_DEV_TO_MEM,
  							 DMA_PREP_INTERRUPT |  DMA_CTRL_ACK);
  
  	if (!tqspi->rx_dma_desc) {
  		dev_err(tqspi->dev, "Unable to get RX descriptor\n");
  		return -EIO;
  	}
  
  	tqspi->rx_dma_desc->callback = tegra_qspi_dma_complete;
  	tqspi->rx_dma_desc->callback_param = &tqspi->rx_dma_complete;
  	dmaengine_submit(tqspi->rx_dma_desc);
  	dma_async_issue_pending(tqspi->rx_dma_chan);
  
  	return 0;
  }
  
  static int tegra_qspi_flush_fifos(struct tegra_qspi *tqspi, bool atomic)
  {
  	void __iomem *addr = tqspi->base + QSPI_FIFO_STATUS;
  	u32 val;
  
  	val = tegra_qspi_readl(tqspi, QSPI_FIFO_STATUS);
  	if ((val & QSPI_FIFO_EMPTY) == QSPI_FIFO_EMPTY)
  		return 0;
  
  	val |= QSPI_RX_FIFO_FLUSH | QSPI_TX_FIFO_FLUSH;
  	tegra_qspi_writel(tqspi, val, QSPI_FIFO_STATUS);
  
  	if (!atomic)
  		return readl_relaxed_poll_timeout(addr, val,
  						  (val & QSPI_FIFO_EMPTY) == QSPI_FIFO_EMPTY,
  						  1000, 1000000);
  
  	return readl_relaxed_poll_timeout_atomic(addr, val,
  						 (val & QSPI_FIFO_EMPTY) == QSPI_FIFO_EMPTY,
  						 1000, 1000000);
  }
  
  static void tegra_qspi_unmask_irq(struct tegra_qspi *tqspi)
  {
  	u32 intr_mask;
  
  	intr_mask = tegra_qspi_readl(tqspi, QSPI_INTR_MASK);
  	intr_mask &= ~(QSPI_INTR_RDY_MASK | QSPI_INTR_RX_TX_FIFO_ERR);
  	tegra_qspi_writel(tqspi, intr_mask, QSPI_INTR_MASK);
  }
  
  static int tegra_qspi_dma_map_xfer(struct tegra_qspi *tqspi, struct spi_transfer *t)
  {
  	u8 *tx_buf = (u8 *)t->tx_buf + tqspi->cur_tx_pos;
  	u8 *rx_buf = (u8 *)t->rx_buf + tqspi->cur_rx_pos;
  	unsigned int len;
  
  	len = DIV_ROUND_UP(tqspi->curr_dma_words * tqspi->bytes_per_word, 4) * 4;
  
  	if (t->tx_buf) {
  		t->tx_dma = dma_map_single(tqspi->dev, (void *)tx_buf, len, DMA_TO_DEVICE);
  		if (dma_mapping_error(tqspi->dev, t->tx_dma))
  			return -ENOMEM;
  	}
  
  	if (t->rx_buf) {
  		t->rx_dma = dma_map_single(tqspi->dev, (void *)rx_buf, len, DMA_FROM_DEVICE);
  		if (dma_mapping_error(tqspi->dev, t->rx_dma)) {
  			dma_unmap_single(tqspi->dev, t->tx_dma, len, DMA_TO_DEVICE);
  			return -ENOMEM;
  		}
  	}
  
  	return 0;
  }
  
  static void tegra_qspi_dma_unmap_xfer(struct tegra_qspi *tqspi, struct spi_transfer *t)
  {
  	unsigned int len;
  
  	len = DIV_ROUND_UP(tqspi->curr_dma_words * tqspi->bytes_per_word, 4) * 4;
  
  	dma_unmap_single(tqspi->dev, t->tx_dma, len, DMA_TO_DEVICE);
  	dma_unmap_single(tqspi->dev, t->rx_dma, len, DMA_FROM_DEVICE);
  }
  
  static int tegra_qspi_start_dma_based_transfer(struct tegra_qspi *tqspi, struct spi_transfer *t)
  {
  	struct dma_slave_config dma_sconfig = { 0 };
  	unsigned int len;
  	u8 dma_burst;
  	int ret = 0;
  	u32 val;
  
  	if (tqspi->is_packed) {
  		ret = tegra_qspi_dma_map_xfer(tqspi, t);
  		if (ret < 0)
  			return ret;
  	}
  
  	val = QSPI_DMA_BLK_SET(tqspi->curr_dma_words - 1);
  	tegra_qspi_writel(tqspi, val, QSPI_DMA_BLK);
  
  	tegra_qspi_unmask_irq(tqspi);
  
  	if (tqspi->is_packed)
  		len = DIV_ROUND_UP(tqspi->curr_dma_words * tqspi->bytes_per_word, 4) * 4;
  	else
  		len = tqspi->curr_dma_words * 4;
  
  	/* set attention level based on length of transfer */
  	val = 0;
  	if (len & 0xf) {
  		val |= QSPI_TX_TRIG_1 | QSPI_RX_TRIG_1;
  		dma_burst = 1;
  	} else if (((len) >> 4) & 0x1) {
  		val |= QSPI_TX_TRIG_4 | QSPI_RX_TRIG_4;
  		dma_burst = 4;
  	} else {
  		val |= QSPI_TX_TRIG_8 | QSPI_RX_TRIG_8;
  		dma_burst = 8;
  	}
  
  	tegra_qspi_writel(tqspi, val, QSPI_DMA_CTL);
  	tqspi->dma_control_reg = val;
  
  	dma_sconfig.device_fc = true;
  	if (tqspi->cur_direction & DATA_DIR_TX) {
  		dma_sconfig.dst_addr = tqspi->phys + QSPI_TX_FIFO;
  		dma_sconfig.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
  		dma_sconfig.dst_maxburst = dma_burst;
  		ret = dmaengine_slave_config(tqspi->tx_dma_chan, &dma_sconfig);
  		if (ret < 0) {
  			dev_err(tqspi->dev, "failed DMA slave config: %d\n", ret);
  			return ret;
  		}
  
  		tegra_qspi_copy_client_txbuf_to_qspi_txbuf(tqspi, t);
  		ret = tegra_qspi_start_tx_dma(tqspi, t, len);
  		if (ret < 0) {
  			dev_err(tqspi->dev, "failed to starting TX DMA: %d\n", ret);
  			return ret;
  		}
  	}
  
  	if (tqspi->cur_direction & DATA_DIR_RX) {
  		dma_sconfig.src_addr = tqspi->phys + QSPI_RX_FIFO;
  		dma_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
  		dma_sconfig.src_maxburst = dma_burst;
  		ret = dmaengine_slave_config(tqspi->rx_dma_chan, &dma_sconfig);
  		if (ret < 0) {
  			dev_err(tqspi->dev, "failed DMA slave config: %d\n", ret);
  			return ret;
  		}
  
  		dma_sync_single_for_device(tqspi->dev, tqspi->rx_dma_phys,
  					   tqspi->dma_buf_size,
  					   DMA_FROM_DEVICE);
  
  		ret = tegra_qspi_start_rx_dma(tqspi, t, len);
  		if (ret < 0) {
  			dev_err(tqspi->dev, "failed to start RX DMA: %d\n", ret);
  			if (tqspi->cur_direction & DATA_DIR_TX)
  				dmaengine_terminate_all(tqspi->tx_dma_chan);
  			return ret;
  		}
  	}
  
  	tegra_qspi_writel(tqspi, tqspi->command1_reg, QSPI_COMMAND1);
  
  	tqspi->is_curr_dma_xfer = true;
  	tqspi->dma_control_reg = val;
  	val |= QSPI_DMA_EN;
  	tegra_qspi_writel(tqspi, val, QSPI_DMA_CTL);
  
  	return ret;
  }
  
  static int tegra_qspi_start_cpu_based_transfer(struct tegra_qspi *qspi, struct spi_transfer *t)
  {
  	u32 val;
  	unsigned int cur_words;
  
  	if (qspi->cur_direction & DATA_DIR_TX)
  		cur_words = tegra_qspi_fill_tx_fifo_from_client_txbuf(qspi, t);
  	else
  		cur_words = qspi->curr_dma_words;
  
  	val = QSPI_DMA_BLK_SET(cur_words - 1);
  	tegra_qspi_writel(qspi, val, QSPI_DMA_BLK);
  
  	tegra_qspi_unmask_irq(qspi);
  
  	qspi->is_curr_dma_xfer = false;
  	val = qspi->command1_reg;
  	val |= QSPI_PIO;
  	tegra_qspi_writel(qspi, val, QSPI_COMMAND1);
  
  	return 0;
  }
  
  static void tegra_qspi_deinit_dma(struct tegra_qspi *tqspi)
  {
  	if (tqspi->tx_dma_buf) {
  		dma_free_coherent(tqspi->dev, tqspi->dma_buf_size,
  				  tqspi->tx_dma_buf, tqspi->tx_dma_phys);
  		tqspi->tx_dma_buf = NULL;
  	}
  
  	if (tqspi->tx_dma_chan) {
  		dma_release_channel(tqspi->tx_dma_chan);
  		tqspi->tx_dma_chan = NULL;
  	}
  
  	if (tqspi->rx_dma_buf) {
  		dma_free_coherent(tqspi->dev, tqspi->dma_buf_size,
  				  tqspi->rx_dma_buf, tqspi->rx_dma_phys);
  		tqspi->rx_dma_buf = NULL;
  	}
  
  	if (tqspi->rx_dma_chan) {
  		dma_release_channel(tqspi->rx_dma_chan);
  		tqspi->rx_dma_chan = NULL;
  	}
  }
  
  static int tegra_qspi_init_dma(struct tegra_qspi *tqspi)
  {
  	struct dma_chan *dma_chan;
  	dma_addr_t dma_phys;
  	u32 *dma_buf;
  	int err;
  
  	dma_chan = dma_request_chan(tqspi->dev, "rx");
  	if (IS_ERR(dma_chan)) {
  		err = PTR_ERR(dma_chan);
  		goto err_out;
  	}
  
  	tqspi->rx_dma_chan = dma_chan;
  
  	dma_buf = dma_alloc_coherent(tqspi->dev, tqspi->dma_buf_size, &dma_phys, GFP_KERNEL);
  	if (!dma_buf) {
  		err = -ENOMEM;
  		goto err_out;
  	}
  
  	tqspi->rx_dma_buf = dma_buf;
  	tqspi->rx_dma_phys = dma_phys;
  
  	dma_chan = dma_request_chan(tqspi->dev, "tx");
  	if (IS_ERR(dma_chan)) {
  		err = PTR_ERR(dma_chan);
  		goto err_out;
  	}
  
  	tqspi->tx_dma_chan = dma_chan;
  
  	dma_buf = dma_alloc_coherent(tqspi->dev, tqspi->dma_buf_size, &dma_phys, GFP_KERNEL);
  	if (!dma_buf) {
  		err = -ENOMEM;
  		goto err_out;
  	}
  
  	tqspi->tx_dma_buf = dma_buf;
  	tqspi->tx_dma_phys = dma_phys;
  	tqspi->use_dma = true;
  
  	return 0;
  
  err_out:
  	tegra_qspi_deinit_dma(tqspi);
  
  	if (err != -EPROBE_DEFER) {
  		dev_err(tqspi->dev, "cannot use DMA: %d\n", err);
  		dev_err(tqspi->dev, "falling back to PIO\n");
  		return 0;
  	}
  
  	return err;
  }
  
  static u32 tegra_qspi_setup_transfer_one(struct spi_device *spi, struct spi_transfer *t,
  					 bool is_first_of_msg)
  {
  	struct tegra_qspi *tqspi = spi_master_get_devdata(spi->master);
  	struct tegra_qspi_client_data *cdata = spi->controller_data;
  	u32 command1, command2, speed = t->speed_hz;
  	u8 bits_per_word = t->bits_per_word;
  	u32 tx_tap = 0, rx_tap = 0;
  	int req_mode;
  
  	if (!has_acpi_companion(tqspi->dev) && speed != tqspi->cur_speed) {
  		clk_set_rate(tqspi->clk, speed);
  		tqspi->cur_speed = speed;
  	}
  
  	tqspi->cur_pos = 0;
  	tqspi->cur_rx_pos = 0;
  	tqspi->cur_tx_pos = 0;
  	tqspi->curr_xfer = t;
  
  	if (is_first_of_msg) {
  		tegra_qspi_mask_clear_irq(tqspi);
  
  		command1 = tqspi->def_command1_reg;
  		command1 |= QSPI_BIT_LENGTH(bits_per_word - 1);
  
  		command1 &= ~QSPI_CONTROL_MODE_MASK;
  		req_mode = spi->mode & 0x3;
  		if (req_mode == SPI_MODE_3)
  			command1 |= QSPI_CONTROL_MODE_3;
  		else
  			command1 |= QSPI_CONTROL_MODE_0;
  
  		if (spi->mode & SPI_CS_HIGH)
  			command1 |= QSPI_CS_SW_VAL;
  		else
  			command1 &= ~QSPI_CS_SW_VAL;
  		tegra_qspi_writel(tqspi, command1, QSPI_COMMAND1);
  
  		if (cdata && cdata->tx_clk_tap_delay)
  			tx_tap = cdata->tx_clk_tap_delay;
  
  		if (cdata && cdata->rx_clk_tap_delay)
  			rx_tap = cdata->rx_clk_tap_delay;
  
  		command2 = QSPI_TX_TAP_DELAY(tx_tap) | QSPI_RX_TAP_DELAY(rx_tap);
  		if (command2 != tqspi->def_command2_reg)
  			tegra_qspi_writel(tqspi, command2, QSPI_COMMAND2);
  
  	} else {
  		command1 = tqspi->command1_reg;
  		command1 &= ~QSPI_BIT_LENGTH(~0);
  		command1 |= QSPI_BIT_LENGTH(bits_per_word - 1);
  	}
  
  	command1 &= ~QSPI_SDR_DDR_SEL;
  
  	return command1;
  }
  
  static int tegra_qspi_start_transfer_one(struct spi_device *spi,
  					 struct spi_transfer *t, u32 command1)
  {
  	struct tegra_qspi *tqspi = spi_master_get_devdata(spi->master);
  	unsigned int total_fifo_words;
  	u8 bus_width = 0;
  	int ret;
  
  	total_fifo_words = tegra_qspi_calculate_curr_xfer_param(tqspi, t);
  
  	command1 &= ~QSPI_PACKED;
  	if (tqspi->is_packed)
  		command1 |= QSPI_PACKED;
  	tegra_qspi_writel(tqspi, command1, QSPI_COMMAND1);
  
  	tqspi->cur_direction = 0;
  
  	command1 &= ~(QSPI_TX_EN | QSPI_RX_EN);
  	if (t->rx_buf) {
  		command1 |= QSPI_RX_EN;
  		tqspi->cur_direction |= DATA_DIR_RX;
  		bus_width = t->rx_nbits;
  	}
  
  	if (t->tx_buf) {
  		command1 |= QSPI_TX_EN;
  		tqspi->cur_direction |= DATA_DIR_TX;
  		bus_width = t->tx_nbits;
  	}
  
  	command1 &= ~QSPI_INTERFACE_WIDTH_MASK;
  
  	if (bus_width == SPI_NBITS_QUAD)
  		command1 |= QSPI_INTERFACE_WIDTH_QUAD;
  	else if (bus_width == SPI_NBITS_DUAL)
  		command1 |= QSPI_INTERFACE_WIDTH_DUAL;
  	else
  		command1 |= QSPI_INTERFACE_WIDTH_SINGLE;
  
  	tqspi->command1_reg = command1;
  
  	tegra_qspi_writel(tqspi, QSPI_NUM_DUMMY_CYCLE(tqspi->dummy_cycles), QSPI_MISC_REG);
  
  	ret = tegra_qspi_flush_fifos(tqspi, false);
  	if (ret < 0)
  		return ret;
  
  	if (tqspi->use_dma && total_fifo_words > QSPI_FIFO_DEPTH)
  		ret = tegra_qspi_start_dma_based_transfer(tqspi, t);
  	else
  		ret = tegra_qspi_start_cpu_based_transfer(tqspi, t);
  
  	return ret;
  }
  
  static struct tegra_qspi_client_data *tegra_qspi_parse_cdata_dt(struct spi_device *spi)
  {
  	struct tegra_qspi_client_data *cdata;
  
  	cdata = devm_kzalloc(&spi->dev, sizeof(*cdata), GFP_KERNEL);
  	if (!cdata)
  		return NULL;
  
  	device_property_read_u32(&spi->dev, "nvidia,tx-clk-tap-delay",
  				 &cdata->tx_clk_tap_delay);
  	device_property_read_u32(&spi->dev, "nvidia,rx-clk-tap-delay",
  				 &cdata->rx_clk_tap_delay);
  
  	return cdata;
  }
  
  static int tegra_qspi_setup(struct spi_device *spi)
  {
  	struct tegra_qspi *tqspi = spi_master_get_devdata(spi->master);
  	struct tegra_qspi_client_data *cdata = spi->controller_data;
  	unsigned long flags;
  	u32 val;
  	int ret;
  
  	ret = pm_runtime_resume_and_get(tqspi->dev);
  	if (ret < 0) {
  		dev_err(tqspi->dev, "failed to get runtime PM: %d\n", ret);
  		return ret;
  	}
  
  	if (!cdata) {
  		cdata = tegra_qspi_parse_cdata_dt(spi);
  		spi->controller_data = cdata;
  	}
  	spin_lock_irqsave(&tqspi->lock, flags);
  
  	/* keep default cs state to inactive */
  	val = tqspi->def_command1_reg;
  	if (spi->mode & SPI_CS_HIGH)
  		val &= ~QSPI_CS_SW_VAL;
  	else
  		val |= QSPI_CS_SW_VAL;
  
  	tqspi->def_command1_reg = val;
  	tegra_qspi_writel(tqspi, tqspi->def_command1_reg, QSPI_COMMAND1);
  
  	spin_unlock_irqrestore(&tqspi->lock, flags);
  
  	pm_runtime_put(tqspi->dev);
  
  	return 0;
  }
  
  static void tegra_qspi_dump_regs(struct tegra_qspi *tqspi)
  {
  	dev_dbg(tqspi->dev, "============ QSPI REGISTER DUMP ============\n");
  	dev_dbg(tqspi->dev, "Command1:    0x%08x | Command2:    0x%08x\n",
  		tegra_qspi_readl(tqspi, QSPI_COMMAND1),
  		tegra_qspi_readl(tqspi, QSPI_COMMAND2));
  	dev_dbg(tqspi->dev, "DMA_CTL:     0x%08x | DMA_BLK:     0x%08x\n",
  		tegra_qspi_readl(tqspi, QSPI_DMA_CTL),
  		tegra_qspi_readl(tqspi, QSPI_DMA_BLK));
  	dev_dbg(tqspi->dev, "INTR_MASK:  0x%08x | MISC: 0x%08x\n",
  		tegra_qspi_readl(tqspi, QSPI_INTR_MASK),
  		tegra_qspi_readl(tqspi, QSPI_MISC_REG));
  	dev_dbg(tqspi->dev, "TRANS_STAT:  0x%08x | FIFO_STATUS: 0x%08x\n",
  		tegra_qspi_readl(tqspi, QSPI_TRANS_STATUS),
  		tegra_qspi_readl(tqspi, QSPI_FIFO_STATUS));
  }
  
  static void tegra_qspi_handle_error(struct tegra_qspi *tqspi)
  {
  	dev_err(tqspi->dev, "error in transfer, fifo status 0x%08x\n", tqspi->status_reg);
  	tegra_qspi_dump_regs(tqspi);
  	tegra_qspi_flush_fifos(tqspi, true);
  	if (device_reset(tqspi->dev) < 0)
  		dev_warn_once(tqspi->dev, "device reset failed\n");
  }
  
  static void tegra_qspi_transfer_end(struct spi_device *spi)
  {
  	struct tegra_qspi *tqspi = spi_master_get_devdata(spi->master);
  	int cs_val = (spi->mode & SPI_CS_HIGH) ? 0 : 1;
  
  	if (cs_val)
  		tqspi->command1_reg |= QSPI_CS_SW_VAL;
  	else
  		tqspi->command1_reg &= ~QSPI_CS_SW_VAL;
  	tegra_qspi_writel(tqspi, tqspi->command1_reg, QSPI_COMMAND1);
  	tegra_qspi_writel(tqspi, tqspi->def_command1_reg, QSPI_COMMAND1);
  }
  
  static u32 tegra_qspi_cmd_config(bool is_ddr, u8 bus_width, u8 len)
  {
  	u32 cmd_config = 0;
  
  	/* Extract Command configuration and value */
  	if (is_ddr)
  		cmd_config |= QSPI_COMMAND_SDR_DDR;
  	else
  		cmd_config &= ~QSPI_COMMAND_SDR_DDR;
  
  	cmd_config |= QSPI_COMMAND_X1_X2_X4(bus_width);
  	cmd_config |= QSPI_COMMAND_SIZE_SET((len * 8) - 1);
  
  	return cmd_config;
  }
  
  static u32 tegra_qspi_addr_config(bool is_ddr, u8 bus_width, u8 len)
  {
  	u32 addr_config = 0;
  
  	/* Extract Address configuration and value */
  	is_ddr = 0; //Only SDR mode supported
  	bus_width = 0; //X1 mode
  
  	if (is_ddr)
  		addr_config |= QSPI_ADDRESS_SDR_DDR;
  	else
  		addr_config &= ~QSPI_ADDRESS_SDR_DDR;
  
  	addr_config |= QSPI_ADDRESS_X1_X2_X4(bus_width);
  	addr_config |= QSPI_ADDRESS_SIZE_SET((len * 8) - 1);
  
  	return addr_config;
  }
  
  static int tegra_qspi_combined_seq_xfer(struct tegra_qspi *tqspi,
  					struct spi_message *msg)
  {
  	bool is_first_msg = true;
  	struct spi_transfer *xfer;
  	struct spi_device *spi = msg->spi;
  	u8 transfer_phase = 0;
  	u32 cmd1 = 0, dma_ctl = 0;
  	int ret = 0;
  	u32 address_value = 0;
  	u32 cmd_config = 0, addr_config = 0;
  	u8 cmd_value = 0, val = 0;
  
  	/* Enable Combined sequence mode */
  	val = tegra_qspi_readl(tqspi, QSPI_GLOBAL_CONFIG);
  	val |= QSPI_CMB_SEQ_EN;
  	tegra_qspi_writel(tqspi, val, QSPI_GLOBAL_CONFIG);
  	/* Process individual transfer list */
  	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
  		switch (transfer_phase) {
  		case CMD_TRANSFER:
  			/* X1 SDR mode */
  			cmd_config = tegra_qspi_cmd_config(false, 0,
  							   xfer->len);
  			cmd_value = *((const u8 *)(xfer->tx_buf));
  			break;
  		case ADDR_TRANSFER:
  			/* X1 SDR mode */
  			addr_config = tegra_qspi_addr_config(false, 0,
  							     xfer->len);
  			address_value = *((const u32 *)(xfer->tx_buf));
  			break;
  		case DATA_TRANSFER:
  			/* Program Command, Address value in register */
  			tegra_qspi_writel(tqspi, cmd_value, QSPI_CMB_SEQ_CMD);
  			tegra_qspi_writel(tqspi, address_value,
  					  QSPI_CMB_SEQ_ADDR);
  			/* Program Command and Address config in register */
  			tegra_qspi_writel(tqspi, cmd_config,
  					  QSPI_CMB_SEQ_CMD_CFG);
  			tegra_qspi_writel(tqspi, addr_config,
  					  QSPI_CMB_SEQ_ADDR_CFG);
  
  			reinit_completion(&tqspi->xfer_completion);
  			cmd1 = tegra_qspi_setup_transfer_one(spi, xfer,
  							     is_first_msg);
  			ret = tegra_qspi_start_transfer_one(spi, xfer,
  							    cmd1);
  
  			if (ret < 0) {
  				dev_err(tqspi->dev, "Failed to start transfer-one: %d\n",
  					ret);
  				return ret;
  			}
  
  			is_first_msg = false;
  			ret = wait_for_completion_timeout
  					(&tqspi->xfer_completion,
  					QSPI_DMA_TIMEOUT);
  
  			if (WARN_ON(ret == 0)) {
  				dev_err(tqspi->dev, "QSPI Transfer failed with timeout: %d\n",
  					ret);
  				if (tqspi->is_curr_dma_xfer &&
  				    (tqspi->cur_direction & DATA_DIR_TX))
  					dmaengine_terminate_all
  						(tqspi->tx_dma_chan);
  
  				if (tqspi->is_curr_dma_xfer &&
  				    (tqspi->cur_direction & DATA_DIR_RX))
  					dmaengine_terminate_all
  						(tqspi->rx_dma_chan);
  
  				/* Abort transfer by resetting pio/dma bit */
  				if (!tqspi->is_curr_dma_xfer) {
  					cmd1 = tegra_qspi_readl
  							(tqspi,
  							 QSPI_COMMAND1);
  					cmd1 &= ~QSPI_PIO;
  					tegra_qspi_writel
  							(tqspi, cmd1,
  							 QSPI_COMMAND1);
  				} else {
  					dma_ctl = tegra_qspi_readl
  							(tqspi,
  							 QSPI_DMA_CTL);
  					dma_ctl &= ~QSPI_DMA_EN;
  					tegra_qspi_writel(tqspi, dma_ctl,
  							  QSPI_DMA_CTL);
  				}
  
  				/* Reset controller if timeout happens */
  				if (device_reset(tqspi->dev) < 0)
  					dev_warn_once(tqspi->dev,
  						      "device reset failed\n");
  				ret = -EIO;
  				goto exit;
  			}
  
  			if (tqspi->tx_status ||  tqspi->rx_status) {
  				dev_err(tqspi->dev, "QSPI Transfer failed\n");
  				tqspi->tx_status = 0;
  				tqspi->rx_status = 0;
  				ret = -EIO;
  				goto exit;
  			}
  			break;
  		default:
  			ret = -EINVAL;
  			goto exit;
  		}
  		msg->actual_length += xfer->len;
  		transfer_phase++;
  	}
  
  exit:
  	msg->status = ret;
  
  	return ret;
  }
  
  static int tegra_qspi_non_combined_seq_xfer(struct tegra_qspi *tqspi,
  					    struct spi_message *msg)
  {
  	struct spi_device *spi = msg->spi;
  	struct spi_transfer *transfer;
  	bool is_first_msg = true;
  	int ret = 0, val = 0;
  
  	msg->status = 0;
  	msg->actual_length = 0;
  	tqspi->tx_status = 0;
  	tqspi->rx_status = 0;
  
  	/* Disable Combined sequence mode */
  	val = tegra_qspi_readl(tqspi, QSPI_GLOBAL_CONFIG);
  	val &= ~QSPI_CMB_SEQ_EN;
  	tegra_qspi_writel(tqspi, val, QSPI_GLOBAL_CONFIG);
  	list_for_each_entry(transfer, &msg->transfers, transfer_list) {
  		struct spi_transfer *xfer = transfer;
  		u8 dummy_bytes = 0;
  		u32 cmd1;
  
  		tqspi->dummy_cycles = 0;
  		/*
  		 * Tegra QSPI hardware supports dummy bytes transfer after actual transfer
  		 * bytes based on programmed dummy clock cycles in the QSPI_MISC register.
  		 * So, check if the next transfer is dummy data transfer and program dummy
  		 * clock cycles along with the current transfer and skip next transfer.
  		 */
  		if (!list_is_last(&xfer->transfer_list, &msg->transfers)) {
  			struct spi_transfer *next_xfer;
  
  			next_xfer = list_next_entry(xfer, transfer_list);
  			if (next_xfer->dummy_data) {
  				u32 dummy_cycles = next_xfer->len * 8 / next_xfer->tx_nbits;
  
  				if (dummy_cycles <= QSPI_DUMMY_CYCLES_MAX) {
  					tqspi->dummy_cycles = dummy_cycles;
  					dummy_bytes = next_xfer->len;
  					transfer = next_xfer;
  				}
  			}
  		}
  
  		reinit_completion(&tqspi->xfer_completion);
  
  		cmd1 = tegra_qspi_setup_transfer_one(spi, xfer, is_first_msg);
  
  		ret = tegra_qspi_start_transfer_one(spi, xfer, cmd1);
  		if (ret < 0) {
  			dev_err(tqspi->dev, "failed to start transfer: %d\n", ret);
  			goto complete_xfer;
  		}
  
  		ret = wait_for_completion_timeout(&tqspi->xfer_completion,
  						  QSPI_DMA_TIMEOUT);
  		if (WARN_ON(ret == 0)) {
  			dev_err(tqspi->dev, "transfer timeout\n");
  			if (tqspi->is_curr_dma_xfer && (tqspi->cur_direction & DATA_DIR_TX))
  				dmaengine_terminate_all(tqspi->tx_dma_chan);
  			if (tqspi->is_curr_dma_xfer && (tqspi->cur_direction & DATA_DIR_RX))
  				dmaengine_terminate_all(tqspi->rx_dma_chan);
  			tegra_qspi_handle_error(tqspi);
  			ret = -EIO;
  			goto complete_xfer;
  		}
  
  		if (tqspi->tx_status ||  tqspi->rx_status) {
  			tegra_qspi_handle_error(tqspi);
  			ret = -EIO;
  			goto complete_xfer;
  		}
  
  		msg->actual_length += xfer->len + dummy_bytes;
  
  complete_xfer:
  		if (ret < 0) {
  			tegra_qspi_transfer_end(spi);
  			spi_transfer_delay_exec(xfer);
  			goto exit;
  		}
  
  		if (list_is_last(&xfer->transfer_list, &msg->transfers)) {
  			/* de-activate CS after last transfer only when cs_change is not set */
  			if (!xfer->cs_change) {
  				tegra_qspi_transfer_end(spi);
  				spi_transfer_delay_exec(xfer);
  			}
  		} else if (xfer->cs_change) {
  			 /* de-activated CS between the transfers only when cs_change is set */
  			tegra_qspi_transfer_end(spi);
  			spi_transfer_delay_exec(xfer);
  		}
  	}
  
  	ret = 0;
  exit:
  	msg->status = ret;
  
  	return ret;
  }
  
  static bool tegra_qspi_validate_cmb_seq(struct tegra_qspi *tqspi,
  					struct spi_message *msg)
  {
  	int transfer_count = 0;
  	struct spi_transfer *xfer;
  
  	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
  		transfer_count++;
  	}
  	if (!tqspi->soc_data->cmb_xfer_capable || transfer_count != 3)
  		return false;
  	xfer = list_first_entry(&msg->transfers, typeof(*xfer),
  				transfer_list);
  	if (xfer->len > 2)
  		return false;
  	xfer = list_next_entry(xfer, transfer_list);
  	if (xfer->len > 4 || xfer->len < 3)
  		return false;
  	xfer = list_next_entry(xfer, transfer_list);
  	if (!tqspi->soc_data->has_dma || xfer->len > (QSPI_FIFO_DEPTH << 2))
  		return false;
  
  	return true;
  }
  
  static int tegra_qspi_transfer_one_message(struct spi_master *master,
  					   struct spi_message *msg)
  {
  	struct tegra_qspi *tqspi = spi_master_get_devdata(master);
  	int ret;
  
  	if (tegra_qspi_validate_cmb_seq(tqspi, msg))
  		ret = tegra_qspi_combined_seq_xfer(tqspi, msg);
  	else
  		ret = tegra_qspi_non_combined_seq_xfer(tqspi, msg);
  
  	spi_finalize_current_message(master);
  
  	return ret;
  }
  
  static irqreturn_t handle_cpu_based_xfer(struct tegra_qspi *tqspi)
  {
  	struct spi_transfer *t = tqspi->curr_xfer;
  	unsigned long flags;
  
  	spin_lock_irqsave(&tqspi->lock, flags);
  
  	if (tqspi->tx_status ||  tqspi->rx_status) {
  		tegra_qspi_handle_error(tqspi);
  		complete(&tqspi->xfer_completion);
  		goto exit;
  	}
  
  	if (tqspi->cur_direction & DATA_DIR_RX)
  		tegra_qspi_read_rx_fifo_to_client_rxbuf(tqspi, t);
  
  	if (tqspi->cur_direction & DATA_DIR_TX)
  		tqspi->cur_pos = tqspi->cur_tx_pos;
  	else
  		tqspi->cur_pos = tqspi->cur_rx_pos;
  
  	if (tqspi->cur_pos == t->len) {
  		complete(&tqspi->xfer_completion);
  		goto exit;
  	}
  
  	tegra_qspi_calculate_curr_xfer_param(tqspi, t);
  	tegra_qspi_start_cpu_based_transfer(tqspi, t);
  exit:
  	spin_unlock_irqrestore(&tqspi->lock, flags);
  	return IRQ_HANDLED;
  }
  
  static irqreturn_t handle_dma_based_xfer(struct tegra_qspi *tqspi)
  {
  	struct spi_transfer *t = tqspi->curr_xfer;
  	unsigned int total_fifo_words;
  	unsigned long flags;
  	long wait_status;
  	int err = 0;
  
  	if (tqspi->cur_direction & DATA_DIR_TX) {
  		if (tqspi->tx_status) {
  			dmaengine_terminate_all(tqspi->tx_dma_chan);
  			err += 1;
  		} else {
  			wait_status = wait_for_completion_interruptible_timeout(
  				&tqspi->tx_dma_complete, QSPI_DMA_TIMEOUT);
  			if (wait_status <= 0) {
  				dmaengine_terminate_all(tqspi->tx_dma_chan);
  				dev_err(tqspi->dev, "failed TX DMA transfer\n");
  				err += 1;
  			}
  		}
  	}
  
  	if (tqspi->cur_direction & DATA_DIR_RX) {
  		if (tqspi->rx_status) {
  			dmaengine_terminate_all(tqspi->rx_dma_chan);
  			err += 2;
  		} else {
  			wait_status = wait_for_completion_interruptible_timeout(
  				&tqspi->rx_dma_complete, QSPI_DMA_TIMEOUT);
  			if (wait_status <= 0) {
  				dmaengine_terminate_all(tqspi->rx_dma_chan);
  				dev_err(tqspi->dev, "failed RX DMA transfer\n");
  				err += 2;
  			}
  		}
  	}
  
  	spin_lock_irqsave(&tqspi->lock, flags);
  
  	if (err) {
  		tegra_qspi_dma_unmap_xfer(tqspi, t);
  		tegra_qspi_handle_error(tqspi);
  		complete(&tqspi->xfer_completion);
  		goto exit;
  	}
  
  	if (tqspi->cur_direction & DATA_DIR_RX)
  		tegra_qspi_copy_qspi_rxbuf_to_client_rxbuf(tqspi, t);
  
  	if (tqspi->cur_direction & DATA_DIR_TX)
  		tqspi->cur_pos = tqspi->cur_tx_pos;
  	else
  		tqspi->cur_pos = tqspi->cur_rx_pos;
  
  	if (tqspi->cur_pos == t->len) {
  		tegra_qspi_dma_unmap_xfer(tqspi, t);
  		complete(&tqspi->xfer_completion);
  		goto exit;
  	}
  
  	tegra_qspi_dma_unmap_xfer(tqspi, t);
  
  	/* continue transfer in current message */
  	total_fifo_words = tegra_qspi_calculate_curr_xfer_param(tqspi, t);
  	if (total_fifo_words > QSPI_FIFO_DEPTH)
  		err = tegra_qspi_start_dma_based_transfer(tqspi, t);
  	else
  		err = tegra_qspi_start_cpu_based_transfer(tqspi, t);
  
  exit:
  	spin_unlock_irqrestore(&tqspi->lock, flags);
  	return IRQ_HANDLED;
  }
  
  static irqreturn_t tegra_qspi_isr_thread(int irq, void *context_data)
  {
  	struct tegra_qspi *tqspi = context_data;
  
  	tqspi->status_reg = tegra_qspi_readl(tqspi, QSPI_FIFO_STATUS);
  
  	if (tqspi->cur_direction & DATA_DIR_TX)
  		tqspi->tx_status = tqspi->status_reg & (QSPI_TX_FIFO_UNF | QSPI_TX_FIFO_OVF);
  
  	if (tqspi->cur_direction & DATA_DIR_RX)
  		tqspi->rx_status = tqspi->status_reg & (QSPI_RX_FIFO_OVF | QSPI_RX_FIFO_UNF);
  
  	tegra_qspi_mask_clear_irq(tqspi);
  
  	if (!tqspi->is_curr_dma_xfer)
  		return handle_cpu_based_xfer(tqspi);
  
  	return handle_dma_based_xfer(tqspi);
  }
  
  static struct tegra_qspi_soc_data tegra210_qspi_soc_data = {
  	.has_dma = true,
  	.cmb_xfer_capable = false,
  };
  
  static struct tegra_qspi_soc_data tegra186_qspi_soc_data = {
  	.has_dma = true,
  	.cmb_xfer_capable = true,
  };
  
  static struct tegra_qspi_soc_data tegra234_qspi_soc_data = {
  	.has_dma = false,
  	.cmb_xfer_capable = true,
  };
  
  static const struct of_device_id tegra_qspi_of_match[] = {
  	{
  		.compatible = "nvidia,tegra210-qspi",
  		.data	    = &tegra210_qspi_soc_data,
  	}, {
  		.compatible = "nvidia,tegra186-qspi",
  		.data	    = &tegra186_qspi_soc_data,
  	}, {
  		.compatible = "nvidia,tegra194-qspi",
  		.data	    = &tegra186_qspi_soc_data,
  	}, {
  		.compatible = "nvidia,tegra234-qspi",
  		.data	    = &tegra234_qspi_soc_data,
  	},
  	{}
  };
  
  MODULE_DEVICE_TABLE(of, tegra_qspi_of_match);
  
  #ifdef CONFIG_ACPI
  static const struct acpi_device_id tegra_qspi_acpi_match[] = {
  	{
  		.id = "NVDA1213",
  		.driver_data = (kernel_ulong_t)&tegra210_qspi_soc_data,
  	}, {
  		.id = "NVDA1313",
  		.driver_data = (kernel_ulong_t)&tegra186_qspi_soc_data,
  	}, {
  		.id = "NVDA1413",
  		.driver_data = (kernel_ulong_t)&tegra234_qspi_soc_data,
  	},
  	{}
  };
  
  MODULE_DEVICE_TABLE(acpi, tegra_qspi_acpi_match);
  #endif
  
  static int tegra_qspi_probe(struct platform_device *pdev)
  {
  	struct spi_master	*master;
  	struct tegra_qspi	*tqspi;
  	struct resource		*r;
  	int ret, qspi_irq;
  	int bus_num;
  
  	master = devm_spi_alloc_master(&pdev->dev, sizeof(*tqspi));
  	if (!master)
  		return -ENOMEM;
  
  	platform_set_drvdata(pdev, master);
  	tqspi = spi_master_get_devdata(master);
  
  	master->mode_bits = SPI_MODE_0 | SPI_MODE_3 | SPI_CS_HIGH |
  			    SPI_TX_DUAL | SPI_RX_DUAL | SPI_TX_QUAD | SPI_RX_QUAD;
  	master->bits_per_word_mask = SPI_BPW_MASK(32) | SPI_BPW_MASK(16) | SPI_BPW_MASK(8);
  	master->setup = tegra_qspi_setup;
  	master->transfer_one_message = tegra_qspi_transfer_one_message;
  	master->num_chipselect = 1;
  	master->auto_runtime_pm = true;
  
  	bus_num = of_alias_get_id(pdev->dev.of_node, "spi");
  	if (bus_num >= 0)
  		master->bus_num = bus_num;
  
  	tqspi->master = master;
  	tqspi->dev = &pdev->dev;
  	spin_lock_init(&tqspi->lock);
  
  	tqspi->soc_data = device_get_match_data(&pdev->dev);
  	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	tqspi->base = devm_ioremap_resource(&pdev->dev, r);
  	if (IS_ERR(tqspi->base))
  		return PTR_ERR(tqspi->base);
  
  	tqspi->phys = r->start;
  	qspi_irq = platform_get_irq(pdev, 0);
  	if (qspi_irq < 0)
  		return qspi_irq;
  	tqspi->irq = qspi_irq;
  
  	if (!has_acpi_companion(tqspi->dev)) {
  		tqspi->clk = devm_clk_get(&pdev->dev, "qspi");
  		if (IS_ERR(tqspi->clk)) {
  			ret = PTR_ERR(tqspi->clk);
  			dev_err(&pdev->dev, "failed to get clock: %d\n", ret);
  			return ret;
  		}
  
  	}
  
  	tqspi->max_buf_size = QSPI_FIFO_DEPTH << 2;
  	tqspi->dma_buf_size = DEFAULT_QSPI_DMA_BUF_LEN;
  
  	ret = tegra_qspi_init_dma(tqspi);
  	if (ret < 0)
  		return ret;
  
  	if (tqspi->use_dma)
  		tqspi->max_buf_size = tqspi->dma_buf_size;
  
  	init_completion(&tqspi->tx_dma_complete);
  	init_completion(&tqspi->rx_dma_complete);
  	init_completion(&tqspi->xfer_completion);
  
  	pm_runtime_enable(&pdev->dev);
  	ret = pm_runtime_resume_and_get(&pdev->dev);
  	if (ret < 0) {
  		dev_err(&pdev->dev, "failed to get runtime PM: %d\n", ret);
  		goto exit_pm_disable;
  	}
  
  	if (device_reset(tqspi->dev) < 0)
  		dev_warn_once(tqspi->dev, "device reset failed\n");
  
  	tqspi->def_command1_reg = QSPI_M_S | QSPI_CS_SW_HW |  QSPI_CS_SW_VAL;
  	tegra_qspi_writel(tqspi, tqspi->def_command1_reg, QSPI_COMMAND1);
  	tqspi->spi_cs_timing1 = tegra_qspi_readl(tqspi, QSPI_CS_TIMING1);
  	tqspi->spi_cs_timing2 = tegra_qspi_readl(tqspi, QSPI_CS_TIMING2);
  	tqspi->def_command2_reg = tegra_qspi_readl(tqspi, QSPI_COMMAND2);
  
  	pm_runtime_put(&pdev->dev);
  
  	ret = request_threaded_irq(tqspi->irq, NULL,
  				   tegra_qspi_isr_thread, IRQF_ONESHOT,
  				   dev_name(&pdev->dev), tqspi);
  	if (ret < 0) {
  		dev_err(&pdev->dev, "failed to request IRQ#%u: %d\n", tqspi->irq, ret);
  		goto exit_pm_disable;
  	}
  
  	master->dev.of_node = pdev->dev.of_node;
  	ret = spi_register_master(master);
  	if (ret < 0) {
  		dev_err(&pdev->dev, "failed to register master: %d\n", ret);
  		goto exit_free_irq;
  	}
  
  	return 0;
  
  exit_free_irq:
  	free_irq(qspi_irq, tqspi);
  exit_pm_disable:
  	pm_runtime_force_suspend(&pdev->dev);
  	tegra_qspi_deinit_dma(tqspi);
  	return ret;
  }
  
  static int tegra_qspi_remove(struct platform_device *pdev)
  {
  	struct spi_master *master = platform_get_drvdata(pdev);
  	struct tegra_qspi *tqspi = spi_master_get_devdata(master);
  
  	spi_unregister_master(master);
  	free_irq(tqspi->irq, tqspi);
  	pm_runtime_force_suspend(&pdev->dev);
  	tegra_qspi_deinit_dma(tqspi);
  
  	return 0;
  }
  
  static int __maybe_unused tegra_qspi_suspend(struct device *dev)
  {
  	struct spi_master *master = dev_get_drvdata(dev);
  
  	return spi_master_suspend(master);
  }
  
  static int __maybe_unused tegra_qspi_resume(struct device *dev)
  {
  	struct spi_master *master = dev_get_drvdata(dev);
  	struct tegra_qspi *tqspi = spi_master_get_devdata(master);
  	int ret;
  
  	ret = pm_runtime_resume_and_get(dev);
  	if (ret < 0) {
  		dev_err(dev, "failed to get runtime PM: %d\n", ret);
  		return ret;
  	}
  
  	tegra_qspi_writel(tqspi, tqspi->command1_reg, QSPI_COMMAND1);
  	tegra_qspi_writel(tqspi, tqspi->def_command2_reg, QSPI_COMMAND2);
  	pm_runtime_put(dev);
  
  	return spi_master_resume(master);
  }
  
  static int __maybe_unused tegra_qspi_runtime_suspend(struct device *dev)
  {
  	struct spi_master *master = dev_get_drvdata(dev);
  	struct tegra_qspi *tqspi = spi_master_get_devdata(master);
  
  	/* Runtime pm disabled with ACPI */
  	if (has_acpi_companion(tqspi->dev))
  		return 0;
  	/* flush all write which are in PPSB queue by reading back */
  	tegra_qspi_readl(tqspi, QSPI_COMMAND1);
  
  	clk_disable_unprepare(tqspi->clk);
  
  	return 0;
  }
  
  static int __maybe_unused tegra_qspi_runtime_resume(struct device *dev)
  {
  	struct spi_master *master = dev_get_drvdata(dev);
  	struct tegra_qspi *tqspi = spi_master_get_devdata(master);
  	int ret;
  
  	/* Runtime pm disabled with ACPI */
  	if (has_acpi_companion(tqspi->dev))
  		return 0;
  	ret = clk_prepare_enable(tqspi->clk);
  	if (ret < 0)
  		dev_err(tqspi->dev, "failed to enable clock: %d\n", ret);
  
  	return ret;
  }
  
  static const struct dev_pm_ops tegra_qspi_pm_ops = {
  	SET_RUNTIME_PM_OPS(tegra_qspi_runtime_suspend, tegra_qspi_runtime_resume, NULL)
  	SET_SYSTEM_SLEEP_PM_OPS(tegra_qspi_suspend, tegra_qspi_resume)
  };
  
  static struct platform_driver tegra_qspi_driver = {
  	.driver = {
  		.name		= "tegra-qspi",
  		.pm		= &tegra_qspi_pm_ops,
  		.of_match_table	= tegra_qspi_of_match,
  		.acpi_match_table = ACPI_PTR(tegra_qspi_acpi_match),
  	},
  	.probe =	tegra_qspi_probe,
  	.remove =	tegra_qspi_remove,
  };
  module_platform_driver(tegra_qspi_driver);
  
  MODULE_ALIAS("platform:qspi-tegra");
  MODULE_DESCRIPTION("NVIDIA Tegra QSPI Controller Driver");
  MODULE_AUTHOR("Sowjanya Komatineni <skomatineni@nvidia.com>");
  MODULE_LICENSE("GPL v2");
  