drivers/spi/spi-bcm63xx-hsspi.c - kernel/bruno - Git at Google

 /*
  * Broadcom BCM63XX High Speed SPI Controller driver
  *
  * Copyright 2000-2010 Broadcom Corporation
  * Copyright 2012-2013 Jonas Gorski <jogo@openwrt.org>
  *
  * Licensed under the GNU/GPL. See COPYING for details.
  */

 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/io.h>
 #include <linux/clk.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/delay.h>
 #include <linux/dma-mapping.h>
 #include <linux/err.h>
 #include <linux/interrupt.h>
 #include <linux/spi/spi.h>
 #include <linux/mutex.h>

 #define HSSPI_GLOBAL_CTRL_REG			0x0
 #define GLOBAL_CTRL_CS_POLARITY_SHIFT		0
 #define GLOBAL_CTRL_CS_POLARITY_MASK		0x000000ff
 #define GLOBAL_CTRL_PLL_CLK_CTRL_SHIFT		8
 #define GLOBAL_CTRL_PLL_CLK_CTRL_MASK		0x0000ff00
 #define GLOBAL_CTRL_CLK_GATE_SSOFF		BIT(16)
 #define GLOBAL_CTRL_CLK_POLARITY		BIT(17)
 #define GLOBAL_CTRL_MOSI_IDLE			BIT(18)

 #define HSSPI_GLOBAL_EXT_TRIGGER_REG		0x4

 #define HSSPI_INT_STATUS_REG			0x8
 #define HSSPI_INT_STATUS_MASKED_REG		0xc
 #define HSSPI_INT_MASK_REG			0x10

 #define HSSPI_PINGx_CMD_DONE(i)			BIT((i * 8) + 0)
 #define HSSPI_PINGx_RX_OVER(i)			BIT((i * 8) + 1)
 #define HSSPI_PINGx_TX_UNDER(i)			BIT((i * 8) + 2)
 #define HSSPI_PINGx_POLL_TIMEOUT(i)		BIT((i * 8) + 3)
 #define HSSPI_PINGx_CTRL_INVAL(i)		BIT((i * 8) + 4)

 #define HSSPI_INT_CLEAR_ALL			0xff001f1f

 #define HSSPI_PINGPONG_COMMAND_REG(x)		(0x80 + (x) * 0x40)
 #define PINGPONG_CMD_COMMAND_MASK		0xf
 #define PINGPONG_COMMAND_NOOP			0
 #define PINGPONG_COMMAND_START_NOW		1
 #define PINGPONG_COMMAND_START_TRIGGER		2
 #define PINGPONG_COMMAND_HALT			3
 #define PINGPONG_COMMAND_FLUSH			4
 #define PINGPONG_CMD_PROFILE_SHIFT		8
 #define PINGPONG_CMD_SS_SHIFT			12

 #define HSSPI_PINGPONG_STATUS_REG(x)		(0x84 + (x) * 0x40)

 #define HSSPI_PROFILE_CLK_CTRL_REG(x)		(0x100 + (x) * 0x20)
 #define CLK_CTRL_FREQ_CTRL_MASK			0x0000ffff
 #define CLK_CTRL_SPI_CLK_2X_SEL			BIT(14)
 #define CLK_CTRL_ACCUM_RST_ON_LOOP		BIT(15)

 #define HSSPI_PROFILE_SIGNAL_CTRL_REG(x)	(0x104 + (x) * 0x20)
 #define SIGNAL_CTRL_LATCH_RISING		BIT(12)
 #define SIGNAL_CTRL_LAUNCH_RISING		BIT(13)
 #define SIGNAL_CTRL_ASYNC_INPUT_PATH		BIT(16)

 #define HSSPI_PROFILE_MODE_CTRL_REG(x)		(0x108 + (x) * 0x20)
 #define MODE_CTRL_MULTIDATA_RD_STRT_SHIFT	8
 #define MODE_CTRL_MULTIDATA_WR_STRT_SHIFT	12
 #define MODE_CTRL_MULTIDATA_RD_SIZE_SHIFT	16
 #define MODE_CTRL_MULTIDATA_WR_SIZE_SHIFT	18
 #define MODE_CTRL_MODE_3WIRE			BIT(20)
 #define MODE_CTRL_PREPENDBYTE_CNT_SHIFT		24

 #define HSSPI_FIFO_REG(x)			(0x200 + (x) * 0x200)


 #define HSSPI_OP_MULTIBIT			BIT(11)
 #define HSSPI_OP_CODE_SHIFT			13
 #define HSSPI_OP_SLEEP				(0 << HSSPI_OP_CODE_SHIFT)
 #define HSSPI_OP_READ_WRITE			(1 << HSSPI_OP_CODE_SHIFT)
 #define HSSPI_OP_WRITE				(2 << HSSPI_OP_CODE_SHIFT)
 #define HSSPI_OP_READ				(3 << HSSPI_OP_CODE_SHIFT)
 #define HSSPI_OP_SETIRQ				(4 << HSSPI_OP_CODE_SHIFT)

 #define HSSPI_BUFFER_LEN			512
 #define HSSPI_OPCODE_LEN			2

 #define HSSPI_MAX_PREPEND_LEN			15

 #define HSSPI_MAX_SYNC_CLOCK			30000000

 #define HSSPI_BUS_NUM				1 /* 0 is legacy SPI */

 struct bcm63xx_hsspi {
 	struct completion done;
 	struct mutex bus_mutex;

 	struct platform_device *pdev;
 	struct clk *clk;
 	void __iomem *regs;
 	u8 __iomem *fifo;

 	u32 speed_hz;
 	u8 cs_polarity;
 };

 static void bcm63xx_hsspi_set_cs(struct bcm63xx_hsspi *bs, unsigned cs,
 				 bool active)
 {
 	u32 reg;

 	mutex_lock(&bs->bus_mutex);
 	reg = __raw_readl(bs->regs + HSSPI_GLOBAL_CTRL_REG);

 	reg &= ~BIT(cs);
 	if (active == !(bs->cs_polarity & BIT(cs)))
 		reg |= BIT(cs);

 	__raw_writel(reg, bs->regs + HSSPI_GLOBAL_CTRL_REG);
 	mutex_unlock(&bs->bus_mutex);
 }

 static void bcm63xx_hsspi_set_clk(struct bcm63xx_hsspi *bs,
 				  struct spi_device *spi, int hz)
 {
 	unsigned profile = spi->chip_select;
 	u32 reg;

 	reg = DIV_ROUND_UP(2048, DIV_ROUND_UP(bs->speed_hz, hz));
 	__raw_writel(CLK_CTRL_ACCUM_RST_ON_LOOP | reg,
 		     bs->regs + HSSPI_PROFILE_CLK_CTRL_REG(profile));

 	reg = __raw_readl(bs->regs + HSSPI_PROFILE_SIGNAL_CTRL_REG(profile));
 	if (hz > HSSPI_MAX_SYNC_CLOCK)
 		reg |= SIGNAL_CTRL_ASYNC_INPUT_PATH;
 	else
 		reg &= ~SIGNAL_CTRL_ASYNC_INPUT_PATH;
 	__raw_writel(reg, bs->regs + HSSPI_PROFILE_SIGNAL_CTRL_REG(profile));

 	mutex_lock(&bs->bus_mutex);
 	/* setup clock polarity */
 	reg = __raw_readl(bs->regs + HSSPI_GLOBAL_CTRL_REG);
 	reg &= ~GLOBAL_CTRL_CLK_POLARITY;
 	if (spi->mode & SPI_CPOL)
 		reg |= GLOBAL_CTRL_CLK_POLARITY;
 	__raw_writel(reg, bs->regs + HSSPI_GLOBAL_CTRL_REG);
 	mutex_unlock(&bs->bus_mutex);
 }

 static int bcm63xx_hsspi_do_txrx(struct spi_device *spi, struct spi_transfer *t)
 {
 	struct bcm63xx_hsspi *bs = spi_master_get_devdata(spi->master);
 	unsigned chip_select = spi->chip_select;
 	u16 opcode = 0;
 	int pending = t->len;
 	int step_size = HSSPI_BUFFER_LEN;
 	const u8 *tx = t->tx_buf;
 	u8 *rx = t->rx_buf;

 	bcm63xx_hsspi_set_clk(bs, spi, t->speed_hz);
 	bcm63xx_hsspi_set_cs(bs, spi->chip_select, true);

 	if (tx && rx)
 		opcode = HSSPI_OP_READ_WRITE;
 	else if (tx)
 		opcode = HSSPI_OP_WRITE;
 	else if (rx)
 		opcode = HSSPI_OP_READ;

 	if (opcode != HSSPI_OP_READ)
 		step_size -= HSSPI_OPCODE_LEN;

 	if ((opcode == HSSPI_OP_READ && t->rx_nbits == SPI_NBITS_DUAL) ||
 	    (opcode == HSSPI_OP_WRITE && t->tx_nbits == SPI_NBITS_DUAL))
 		opcode |= HSSPI_OP_MULTIBIT;

 	__raw_writel(1 << MODE_CTRL_MULTIDATA_WR_SIZE_SHIFT |
 		     1 << MODE_CTRL_MULTIDATA_RD_SIZE_SHIFT | 0xff,
 		     bs->regs + HSSPI_PROFILE_MODE_CTRL_REG(chip_select));

 	while (pending > 0) {
 		int curr_step = min_t(int, step_size, pending);

 		reinit_completion(&bs->done);
 		if (tx) {
 			memcpy_toio(bs->fifo + HSSPI_OPCODE_LEN, tx, curr_step);
 			tx += curr_step;
 		}

 		__raw_writew(opcode | curr_step, bs->fifo);

 		/* enable interrupt */
 		__raw_writel(HSSPI_PINGx_CMD_DONE(0),
 			     bs->regs + HSSPI_INT_MASK_REG);

 		/* start the transfer */
 		__raw_writel(!chip_select << PINGPONG_CMD_SS_SHIFT |
 			     chip_select << PINGPONG_CMD_PROFILE_SHIFT |
 			     PINGPONG_COMMAND_START_NOW,
 			     bs->regs + HSSPI_PINGPONG_COMMAND_REG(0));

 		if (wait_for_completion_timeout(&bs->done, HZ) == 0) {
 			dev_err(&bs->pdev->dev, "transfer timed out!\n");
 			return -ETIMEDOUT;
 		}

 		if (rx) {
 			memcpy_fromio(rx, bs->fifo, curr_step);
 			rx += curr_step;
 		}

 		pending -= curr_step;
 	}

 	return 0;
 }

 static int bcm63xx_hsspi_setup(struct spi_device *spi)
 {
 	struct bcm63xx_hsspi *bs = spi_master_get_devdata(spi->master);
 	u32 reg;

 	reg = __raw_readl(bs->regs +
 			  HSSPI_PROFILE_SIGNAL_CTRL_REG(spi->chip_select));
 	reg &= ~(SIGNAL_CTRL_LAUNCH_RISING | SIGNAL_CTRL_LATCH_RISING);
 	if (spi->mode & SPI_CPHA)
 		reg |= SIGNAL_CTRL_LAUNCH_RISING;
 	else
 		reg |= SIGNAL_CTRL_LATCH_RISING;
 	__raw_writel(reg, bs->regs +
 		     HSSPI_PROFILE_SIGNAL_CTRL_REG(spi->chip_select));

 	mutex_lock(&bs->bus_mutex);
 	reg = __raw_readl(bs->regs + HSSPI_GLOBAL_CTRL_REG);

 	/* only change actual polarities if there is no transfer */
 	if ((reg & GLOBAL_CTRL_CS_POLARITY_MASK) == bs->cs_polarity) {
 		if (spi->mode & SPI_CS_HIGH)
 			reg |= BIT(spi->chip_select);
 		else
 			reg &= ~BIT(spi->chip_select);
 		__raw_writel(reg, bs->regs + HSSPI_GLOBAL_CTRL_REG);
 	}

 	if (spi->mode & SPI_CS_HIGH)
 		bs->cs_polarity |= BIT(spi->chip_select);
 	else
 		bs->cs_polarity &= ~BIT(spi->chip_select);

 	mutex_unlock(&bs->bus_mutex);

 	return 0;
 }

 static int bcm63xx_hsspi_transfer_one(struct spi_master *master,
 				      struct spi_message *msg)
 {
 	struct bcm63xx_hsspi *bs = spi_master_get_devdata(master);
 	struct spi_transfer *t;
 	struct spi_device *spi = msg->spi;
 	int status = -EINVAL;
 	int dummy_cs;
 	u32 reg;

 	/* This controller does not support keeping CS active during idle.
 	 * To work around this, we use the following ugly hack:
 	 *
 	 * a. Invert the target chip select's polarity so it will be active.
 	 * b. Select a "dummy" chip select to use as the hardware target.
 	 * c. Invert the dummy chip select's polarity so it will be inactive
 	 *    during the actual transfers.
 	 * d. Tell the hardware to send to the dummy chip select. Thanks to
 	 *    the multiplexed nature of SPI the actual target will receive
 	 *    the transfer and we see its response.
 	 *
 	 * e. At the end restore the polarities again to their default values.
 	 */

 	dummy_cs = !spi->chip_select;
 	bcm63xx_hsspi_set_cs(bs, dummy_cs, true);

 	list_for_each_entry(t, &msg->transfers, transfer_list) {
 		status = bcm63xx_hsspi_do_txrx(spi, t);
 		if (status)
 			break;

 		msg->actual_length += t->len;

 		if (t->delay_usecs)
 			udelay(t->delay_usecs);

 		if (t->cs_change)
 			bcm63xx_hsspi_set_cs(bs, spi->chip_select, false);
 	}

 	mutex_lock(&bs->bus_mutex);
 	reg = __raw_readl(bs->regs + HSSPI_GLOBAL_CTRL_REG);
 	reg &= ~GLOBAL_CTRL_CS_POLARITY_MASK;
 	reg |= bs->cs_polarity;
 	__raw_writel(reg, bs->regs + HSSPI_GLOBAL_CTRL_REG);
 	mutex_unlock(&bs->bus_mutex);

 	msg->status = status;
 	spi_finalize_current_message(master);

 	return 0;
 }

 static irqreturn_t bcm63xx_hsspi_interrupt(int irq, void *dev_id)
 {
 	struct bcm63xx_hsspi *bs = (struct bcm63xx_hsspi *)dev_id;

 	if (__raw_readl(bs->regs + HSSPI_INT_STATUS_MASKED_REG) == 0)
 		return IRQ_NONE;

 	__raw_writel(HSSPI_INT_CLEAR_ALL, bs->regs + HSSPI_INT_STATUS_REG);
 	__raw_writel(0, bs->regs + HSSPI_INT_MASK_REG);

 	complete(&bs->done);

 	return IRQ_HANDLED;
 }

 static int bcm63xx_hsspi_probe(struct platform_device *pdev)
 {
 	struct spi_master *master;
 	struct bcm63xx_hsspi *bs;
 	struct resource *res_mem;
 	void __iomem *regs;
 	struct device *dev = &pdev->dev;
 	struct clk *clk;
 	int irq, ret;
 	u32 reg, rate;

 	irq = platform_get_irq(pdev, 0);
 	if (irq < 0) {
 		dev_err(dev, "no irq\n");
 		return -ENXIO;
 	}

 	res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	regs = devm_ioremap_resource(dev, res_mem);
 	if (IS_ERR(regs))
 		return PTR_ERR(regs);

 	clk = devm_clk_get(dev, "hsspi");

 	if (IS_ERR(clk))
 		return PTR_ERR(clk);

 	rate = clk_get_rate(clk);
 	if (!rate)
 		return -EINVAL;

 	ret = clk_prepare_enable(clk);
 	if (ret)
 		return ret;

 	master = spi_alloc_master(&pdev->dev, sizeof(*bs));
 	if (!master) {
 		ret = -ENOMEM;
 		goto out_disable_clk;
 	}

 	bs = spi_master_get_devdata(master);
 	bs->pdev = pdev;
 	bs->clk = clk;
 	bs->regs = regs;
 	bs->speed_hz = rate;
 	bs->fifo = (u8 __iomem *)(bs->regs + HSSPI_FIFO_REG(0));

 	mutex_init(&bs->bus_mutex);
 	init_completion(&bs->done);

 	master->bus_num = HSSPI_BUS_NUM;
 	master->num_chipselect = 8;
 	master->setup = bcm63xx_hsspi_setup;
 	master->transfer_one_message = bcm63xx_hsspi_transfer_one;
 	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH |
 			    SPI_RX_DUAL | SPI_TX_DUAL;
 	master->bits_per_word_mask = SPI_BPW_MASK(8);
 	master->auto_runtime_pm = true;

 	platform_set_drvdata(pdev, master);

 	/* Initialize the hardware */
 	__raw_writel(0, bs->regs + HSSPI_INT_MASK_REG);

 	/* clean up any pending interrupts */
 	__raw_writel(HSSPI_INT_CLEAR_ALL, bs->regs + HSSPI_INT_STATUS_REG);

 	/* read out default CS polarities */
 	reg = __raw_readl(bs->regs + HSSPI_GLOBAL_CTRL_REG);
 	bs->cs_polarity = reg & GLOBAL_CTRL_CS_POLARITY_MASK;
 	__raw_writel(reg | GLOBAL_CTRL_CLK_GATE_SSOFF,
 		     bs->regs + HSSPI_GLOBAL_CTRL_REG);

 	ret = devm_request_irq(dev, irq, bcm63xx_hsspi_interrupt, IRQF_SHARED,
 			       pdev->name, bs);

 	if (ret)
 		goto out_put_master;

 	/* register and we are done */
 	ret = devm_spi_register_master(dev, master);
 	if (ret)
 		goto out_put_master;

 	return 0;

 out_put_master:
 	spi_master_put(master);
 out_disable_clk:
 	clk_disable_unprepare(clk);
 	return ret;
 }


 static int bcm63xx_hsspi_remove(struct platform_device *pdev)
 {
 	struct spi_master *master = platform_get_drvdata(pdev);
 	struct bcm63xx_hsspi *bs = spi_master_get_devdata(master);

 	/* reset the hardware and block queue progress */
 	__raw_writel(0, bs->regs + HSSPI_INT_MASK_REG);
 	clk_disable_unprepare(bs->clk);

 	return 0;
 }

 #ifdef CONFIG_PM_SLEEP
 static int bcm63xx_hsspi_suspend(struct device *dev)
 {
 	struct spi_master *master = dev_get_drvdata(dev);
 	struct bcm63xx_hsspi *bs = spi_master_get_devdata(master);

 	spi_master_suspend(master);
 	clk_disable_unprepare(bs->clk);

 	return 0;
 }

 static int bcm63xx_hsspi_resume(struct device *dev)
 {
 	struct spi_master *master = dev_get_drvdata(dev);
 	struct bcm63xx_hsspi *bs = spi_master_get_devdata(master);
 	int ret;

 	ret = clk_prepare_enable(bs->clk);
 	if (ret)
 		return ret;

 	spi_master_resume(master);

 	return 0;
 }
 #endif

 static SIMPLE_DEV_PM_OPS(bcm63xx_hsspi_pm_ops, bcm63xx_hsspi_suspend,
 			 bcm63xx_hsspi_resume);

 static struct platform_driver bcm63xx_hsspi_driver = {
 	.driver = {
 		.name	= "bcm63xx-hsspi",
 		.pm	= &bcm63xx_hsspi_pm_ops,
 	},
 	.probe		= bcm63xx_hsspi_probe,
 	.remove		= bcm63xx_hsspi_remove,
 };

 module_platform_driver(bcm63xx_hsspi_driver);

 MODULE_ALIAS("platform:bcm63xx_hsspi");
 MODULE_DESCRIPTION("Broadcom BCM63xx High Speed SPI Controller driver");
 MODULE_AUTHOR("Jonas Gorski <jogo@openwrt.org>");
 MODULE_LICENSE("GPL");
	/*
	* Broadcom BCM63XX High Speed SPI Controller driver
	*
	* Copyright 2000-2010 Broadcom Corporation
	* Copyright 2012-2013 Jonas Gorski <jogo@openwrt.org>
	*
	* Licensed under the GNU/GPL. See COPYING for details.
	*/

	#include <linux/kernel.h>
	#include <linux/init.h>
	#include <linux/io.h>
	#include <linux/clk.h>
	#include <linux/module.h>
	#include <linux/platform_device.h>
	#include <linux/delay.h>
	#include <linux/dma-mapping.h>
	#include <linux/err.h>
	#include <linux/interrupt.h>
	#include <linux/spi/spi.h>
	#include <linux/mutex.h>

	#define HSSPI_GLOBAL_CTRL_REG 0x0
	#define GLOBAL_CTRL_CS_POLARITY_SHIFT 0
	#define GLOBAL_CTRL_CS_POLARITY_MASK 0x000000ff
	#define GLOBAL_CTRL_PLL_CLK_CTRL_SHIFT 8
	#define GLOBAL_CTRL_PLL_CLK_CTRL_MASK 0x0000ff00
	#define GLOBAL_CTRL_CLK_GATE_SSOFF BIT(16)
	#define GLOBAL_CTRL_CLK_POLARITY BIT(17)
	#define GLOBAL_CTRL_MOSI_IDLE BIT(18)

	#define HSSPI_GLOBAL_EXT_TRIGGER_REG 0x4

	#define HSSPI_INT_STATUS_REG 0x8
	#define HSSPI_INT_STATUS_MASKED_REG 0xc
	#define HSSPI_INT_MASK_REG 0x10

	#define HSSPI_PINGx_CMD_DONE(i) BIT((i * 8) + 0)
	#define HSSPI_PINGx_RX_OVER(i) BIT((i * 8) + 1)
	#define HSSPI_PINGx_TX_UNDER(i) BIT((i * 8) + 2)
	#define HSSPI_PINGx_POLL_TIMEOUT(i) BIT((i * 8) + 3)
	#define HSSPI_PINGx_CTRL_INVAL(i) BIT((i * 8) + 4)

	#define HSSPI_INT_CLEAR_ALL 0xff001f1f

	#define HSSPI_PINGPONG_COMMAND_REG(x) (0x80 + (x) * 0x40)
	#define PINGPONG_CMD_COMMAND_MASK 0xf
	#define PINGPONG_COMMAND_NOOP 0
	#define PINGPONG_COMMAND_START_NOW 1
	#define PINGPONG_COMMAND_START_TRIGGER 2
	#define PINGPONG_COMMAND_HALT 3
	#define PINGPONG_COMMAND_FLUSH 4
	#define PINGPONG_CMD_PROFILE_SHIFT 8
	#define PINGPONG_CMD_SS_SHIFT 12

	#define HSSPI_PINGPONG_STATUS_REG(x) (0x84 + (x) * 0x40)

	#define HSSPI_PROFILE_CLK_CTRL_REG(x) (0x100 + (x) * 0x20)
	#define CLK_CTRL_FREQ_CTRL_MASK 0x0000ffff
	#define CLK_CTRL_SPI_CLK_2X_SEL BIT(14)
	#define CLK_CTRL_ACCUM_RST_ON_LOOP BIT(15)

	#define HSSPI_PROFILE_SIGNAL_CTRL_REG(x) (0x104 + (x) * 0x20)
	#define SIGNAL_CTRL_LATCH_RISING BIT(12)
	#define SIGNAL_CTRL_LAUNCH_RISING BIT(13)
	#define SIGNAL_CTRL_ASYNC_INPUT_PATH BIT(16)

	#define HSSPI_PROFILE_MODE_CTRL_REG(x) (0x108 + (x) * 0x20)
	#define MODE_CTRL_MULTIDATA_RD_STRT_SHIFT 8
	#define MODE_CTRL_MULTIDATA_WR_STRT_SHIFT 12
	#define MODE_CTRL_MULTIDATA_RD_SIZE_SHIFT 16
	#define MODE_CTRL_MULTIDATA_WR_SIZE_SHIFT 18
	#define MODE_CTRL_MODE_3WIRE BIT(20)
	#define MODE_CTRL_PREPENDBYTE_CNT_SHIFT 24

	#define HSSPI_FIFO_REG(x) (0x200 + (x) * 0x200)


	#define HSSPI_OP_MULTIBIT BIT(11)
	#define HSSPI_OP_CODE_SHIFT 13
	#define HSSPI_OP_SLEEP (0 << HSSPI_OP_CODE_SHIFT)
	#define HSSPI_OP_READ_WRITE (1 << HSSPI_OP_CODE_SHIFT)
	#define HSSPI_OP_WRITE (2 << HSSPI_OP_CODE_SHIFT)
	#define HSSPI_OP_READ (3 << HSSPI_OP_CODE_SHIFT)
	#define HSSPI_OP_SETIRQ (4 << HSSPI_OP_CODE_SHIFT)

	#define HSSPI_BUFFER_LEN 512
	#define HSSPI_OPCODE_LEN 2

	#define HSSPI_MAX_PREPEND_LEN 15

	#define HSSPI_MAX_SYNC_CLOCK 30000000

	#define HSSPI_BUS_NUM 1 /* 0 is legacy SPI */

	struct bcm63xx_hsspi {
	struct completion done;
	struct mutex bus_mutex;

	struct platform_device *pdev;
	struct clk *clk;
	void __iomem *regs;
	u8 __iomem *fifo;

	u32 speed_hz;
	u8 cs_polarity;
	};

	static void bcm63xx_hsspi_set_cs(struct bcm63xx_hsspi *bs, unsigned cs,
	bool active)
	{
	u32 reg;

	mutex_lock(&bs->bus_mutex);
	reg = __raw_readl(bs->regs + HSSPI_GLOBAL_CTRL_REG);

	reg &= ~BIT(cs);
	if (active == !(bs->cs_polarity & BIT(cs)))
	reg \|= BIT(cs);

	__raw_writel(reg, bs->regs + HSSPI_GLOBAL_CTRL_REG);
	mutex_unlock(&bs->bus_mutex);
	}

	static void bcm63xx_hsspi_set_clk(struct bcm63xx_hsspi *bs,
	struct spi_device *spi, int hz)
	{
	unsigned profile = spi->chip_select;
	u32 reg;

	reg = DIV_ROUND_UP(2048, DIV_ROUND_UP(bs->speed_hz, hz));
	__raw_writel(CLK_CTRL_ACCUM_RST_ON_LOOP \| reg,
	bs->regs + HSSPI_PROFILE_CLK_CTRL_REG(profile));

	reg = __raw_readl(bs->regs + HSSPI_PROFILE_SIGNAL_CTRL_REG(profile));
	if (hz > HSSPI_MAX_SYNC_CLOCK)
	reg \|= SIGNAL_CTRL_ASYNC_INPUT_PATH;
	else
	reg &= ~SIGNAL_CTRL_ASYNC_INPUT_PATH;
	__raw_writel(reg, bs->regs + HSSPI_PROFILE_SIGNAL_CTRL_REG(profile));

	mutex_lock(&bs->bus_mutex);
	/* setup clock polarity */
	reg = __raw_readl(bs->regs + HSSPI_GLOBAL_CTRL_REG);
	reg &= ~GLOBAL_CTRL_CLK_POLARITY;
	if (spi->mode & SPI_CPOL)
	reg \|= GLOBAL_CTRL_CLK_POLARITY;
	__raw_writel(reg, bs->regs + HSSPI_GLOBAL_CTRL_REG);
	mutex_unlock(&bs->bus_mutex);
	}

	static int bcm63xx_hsspi_do_txrx(struct spi_device spi, struct spi_transfer t)
	{
	struct bcm63xx_hsspi *bs = spi_master_get_devdata(spi->master);
	unsigned chip_select = spi->chip_select;
	u16 opcode = 0;
	int pending = t->len;
	int step_size = HSSPI_BUFFER_LEN;
	const u8 *tx = t->tx_buf;
	u8 *rx = t->rx_buf;

	bcm63xx_hsspi_set_clk(bs, spi, t->speed_hz);
	bcm63xx_hsspi_set_cs(bs, spi->chip_select, true);

	if (tx && rx)
	opcode = HSSPI_OP_READ_WRITE;
	else if (tx)
	opcode = HSSPI_OP_WRITE;
	else if (rx)
	opcode = HSSPI_OP_READ;

	if (opcode != HSSPI_OP_READ)
	step_size -= HSSPI_OPCODE_LEN;

	if ((opcode == HSSPI_OP_READ && t->rx_nbits == SPI_NBITS_DUAL) \|\|
	(opcode == HSSPI_OP_WRITE && t->tx_nbits == SPI_NBITS_DUAL))
	opcode \|= HSSPI_OP_MULTIBIT;

	__raw_writel(1 << MODE_CTRL_MULTIDATA_WR_SIZE_SHIFT \|
	1 << MODE_CTRL_MULTIDATA_RD_SIZE_SHIFT \| 0xff,
	bs->regs + HSSPI_PROFILE_MODE_CTRL_REG(chip_select));

	while (pending > 0) {
	int curr_step = min_t(int, step_size, pending);

	reinit_completion(&bs->done);
	if (tx) {
	memcpy_toio(bs->fifo + HSSPI_OPCODE_LEN, tx, curr_step);
	tx += curr_step;
	}

	__raw_writew(opcode \| curr_step, bs->fifo);

	/* enable interrupt */
	__raw_writel(HSSPI_PINGx_CMD_DONE(0),
	bs->regs + HSSPI_INT_MASK_REG);

	/* start the transfer */
	__raw_writel(!chip_select << PINGPONG_CMD_SS_SHIFT \|
	chip_select << PINGPONG_CMD_PROFILE_SHIFT \|
	PINGPONG_COMMAND_START_NOW,
	bs->regs + HSSPI_PINGPONG_COMMAND_REG(0));

	if (wait_for_completion_timeout(&bs->done, HZ) == 0) {
	dev_err(&bs->pdev->dev, "transfer timed out!\n");
	return -ETIMEDOUT;
	}

	if (rx) {
	memcpy_fromio(rx, bs->fifo, curr_step);
	rx += curr_step;
	}

	pending -= curr_step;
	}

	return 0;
	}

	static int bcm63xx_hsspi_setup(struct spi_device *spi)
	{
	struct bcm63xx_hsspi *bs = spi_master_get_devdata(spi->master);
	u32 reg;

	reg = __raw_readl(bs->regs +
	HSSPI_PROFILE_SIGNAL_CTRL_REG(spi->chip_select));
	reg &= ~(SIGNAL_CTRL_LAUNCH_RISING \| SIGNAL_CTRL_LATCH_RISING);
	if (spi->mode & SPI_CPHA)
	reg \|= SIGNAL_CTRL_LAUNCH_RISING;
	else
	reg \|= SIGNAL_CTRL_LATCH_RISING;
	__raw_writel(reg, bs->regs +
	HSSPI_PROFILE_SIGNAL_CTRL_REG(spi->chip_select));

	mutex_lock(&bs->bus_mutex);
	reg = __raw_readl(bs->regs + HSSPI_GLOBAL_CTRL_REG);

	/* only change actual polarities if there is no transfer */
	if ((reg & GLOBAL_CTRL_CS_POLARITY_MASK) == bs->cs_polarity) {
	if (spi->mode & SPI_CS_HIGH)
	reg \|= BIT(spi->chip_select);
	else
	reg &= ~BIT(spi->chip_select);
	__raw_writel(reg, bs->regs + HSSPI_GLOBAL_CTRL_REG);
	}

	if (spi->mode & SPI_CS_HIGH)
	bs->cs_polarity \|= BIT(spi->chip_select);
	else
	bs->cs_polarity &= ~BIT(spi->chip_select);

	mutex_unlock(&bs->bus_mutex);

	return 0;
	}

	static int bcm63xx_hsspi_transfer_one(struct spi_master *master,
	struct spi_message *msg)
	{
	struct bcm63xx_hsspi *bs = spi_master_get_devdata(master);
	struct spi_transfer *t;
	struct spi_device *spi = msg->spi;
	int status = -EINVAL;
	int dummy_cs;
	u32 reg;

	/* This controller does not support keeping CS active during idle.
	* To work around this, we use the following ugly hack:
	*
	* a. Invert the target chip select's polarity so it will be active.
	* b. Select a "dummy" chip select to use as the hardware target.
	* c. Invert the dummy chip select's polarity so it will be inactive
	* during the actual transfers.
	* d. Tell the hardware to send to the dummy chip select. Thanks to
	* the multiplexed nature of SPI the actual target will receive
	* the transfer and we see its response.
	*
	* e. At the end restore the polarities again to their default values.
	*/

	dummy_cs = !spi->chip_select;
	bcm63xx_hsspi_set_cs(bs, dummy_cs, true);

	list_for_each_entry(t, &msg->transfers, transfer_list) {
	status = bcm63xx_hsspi_do_txrx(spi, t);
	if (status)
	break;

	msg->actual_length += t->len;

	if (t->delay_usecs)
	udelay(t->delay_usecs);

	if (t->cs_change)
	bcm63xx_hsspi_set_cs(bs, spi->chip_select, false);
	}

	mutex_lock(&bs->bus_mutex);
	reg = __raw_readl(bs->regs + HSSPI_GLOBAL_CTRL_REG);
	reg &= ~GLOBAL_CTRL_CS_POLARITY_MASK;
	reg \|= bs->cs_polarity;
	__raw_writel(reg, bs->regs + HSSPI_GLOBAL_CTRL_REG);
	mutex_unlock(&bs->bus_mutex);

	msg->status = status;
	spi_finalize_current_message(master);

	return 0;
	}

	static irqreturn_t bcm63xx_hsspi_interrupt(int irq, void *dev_id)
	{
	struct bcm63xx_hsspi bs = (struct bcm63xx_hsspi )dev_id;

	if (__raw_readl(bs->regs + HSSPI_INT_STATUS_MASKED_REG) == 0)
	return IRQ_NONE;

	__raw_writel(HSSPI_INT_CLEAR_ALL, bs->regs + HSSPI_INT_STATUS_REG);
	__raw_writel(0, bs->regs + HSSPI_INT_MASK_REG);

	complete(&bs->done);

	return IRQ_HANDLED;
	}

	static int bcm63xx_hsspi_probe(struct platform_device *pdev)
	{
	struct spi_master *master;
	struct bcm63xx_hsspi *bs;
	struct resource *res_mem;
	void __iomem *regs;
	struct device *dev = &pdev->dev;
	struct clk *clk;
	int irq, ret;
	u32 reg, rate;

	irq = platform_get_irq(pdev, 0);
	if (irq < 0) {
	dev_err(dev, "no irq\n");
	return -ENXIO;
	}

	res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	regs = devm_ioremap_resource(dev, res_mem);
	if (IS_ERR(regs))
	return PTR_ERR(regs);

	clk = devm_clk_get(dev, "hsspi");

	if (IS_ERR(clk))
	return PTR_ERR(clk);

	rate = clk_get_rate(clk);
	if (!rate)
	return -EINVAL;

	ret = clk_prepare_enable(clk);
	if (ret)
	return ret;

	master = spi_alloc_master(&pdev->dev, sizeof(*bs));
	if (!master) {
	ret = -ENOMEM;
	goto out_disable_clk;
	}

	bs = spi_master_get_devdata(master);
	bs->pdev = pdev;
	bs->clk = clk;
	bs->regs = regs;
	bs->speed_hz = rate;
	bs->fifo = (u8 __iomem *)(bs->regs + HSSPI_FIFO_REG(0));

	mutex_init(&bs->bus_mutex);
	init_completion(&bs->done);

	master->bus_num = HSSPI_BUS_NUM;
	master->num_chipselect = 8;
	master->setup = bcm63xx_hsspi_setup;
	master->transfer_one_message = bcm63xx_hsspi_transfer_one;
	master->mode_bits = SPI_CPOL \| SPI_CPHA \| SPI_CS_HIGH \|
	SPI_RX_DUAL \| SPI_TX_DUAL;
	master->bits_per_word_mask = SPI_BPW_MASK(8);
	master->auto_runtime_pm = true;

	platform_set_drvdata(pdev, master);

	/* Initialize the hardware */
	__raw_writel(0, bs->regs + HSSPI_INT_MASK_REG);

	/* clean up any pending interrupts */
	__raw_writel(HSSPI_INT_CLEAR_ALL, bs->regs + HSSPI_INT_STATUS_REG);

	/* read out default CS polarities */
	reg = __raw_readl(bs->regs + HSSPI_GLOBAL_CTRL_REG);
	bs->cs_polarity = reg & GLOBAL_CTRL_CS_POLARITY_MASK;
	__raw_writel(reg \| GLOBAL_CTRL_CLK_GATE_SSOFF,
	bs->regs + HSSPI_GLOBAL_CTRL_REG);

	ret = devm_request_irq(dev, irq, bcm63xx_hsspi_interrupt, IRQF_SHARED,
	pdev->name, bs);

	if (ret)
	goto out_put_master;

	/* register and we are done */
	ret = devm_spi_register_master(dev, master);
	if (ret)
	goto out_put_master;

	return 0;

	out_put_master:
	spi_master_put(master);
	out_disable_clk:
	clk_disable_unprepare(clk);
	return ret;
	}


	static int bcm63xx_hsspi_remove(struct platform_device *pdev)
	{
	struct spi_master *master = platform_get_drvdata(pdev);
	struct bcm63xx_hsspi *bs = spi_master_get_devdata(master);

	/* reset the hardware and block queue progress */
	__raw_writel(0, bs->regs + HSSPI_INT_MASK_REG);
	clk_disable_unprepare(bs->clk);

	return 0;
	}

	#ifdef CONFIG_PM_SLEEP
	static int bcm63xx_hsspi_suspend(struct device *dev)
	{
	struct spi_master *master = dev_get_drvdata(dev);
	struct bcm63xx_hsspi *bs = spi_master_get_devdata(master);

	spi_master_suspend(master);
	clk_disable_unprepare(bs->clk);

	return 0;
	}

	static int bcm63xx_hsspi_resume(struct device *dev)
	{
	struct spi_master *master = dev_get_drvdata(dev);
	struct bcm63xx_hsspi *bs = spi_master_get_devdata(master);
	int ret;

	ret = clk_prepare_enable(bs->clk);
	if (ret)
	return ret;

	spi_master_resume(master);

	return 0;
	}
	#endif

	static SIMPLE_DEV_PM_OPS(bcm63xx_hsspi_pm_ops, bcm63xx_hsspi_suspend,
	bcm63xx_hsspi_resume);

	static struct platform_driver bcm63xx_hsspi_driver = {
	.driver = {
	.name = "bcm63xx-hsspi",
	.pm = &bcm63xx_hsspi_pm_ops,
	},
	.probe = bcm63xx_hsspi_probe,
	.remove = bcm63xx_hsspi_remove,
	};

	module_platform_driver(bcm63xx_hsspi_driver);

	MODULE_ALIAS("platform:bcm63xx_hsspi");
	MODULE_DESCRIPTION("Broadcom BCM63xx High Speed SPI Controller driver");
	MODULE_AUTHOR("Jonas Gorski <jogo@openwrt.org>");
	MODULE_LICENSE("GPL");