spi: bcm63xx-hsspi: add bcm63xx HSSPI driver

Add a driver for the High Speed SPI controller found on newer BCM63XX SoCs.

It does feature some new modes like 3-wire or dual spi, but neither of it
is currently implemented.

Signed-off-by: Jonas Gorski <jogo@openwrt.org>
Signed-off-by: Mark Brown <broonie@linaro.org>

1 files changed, 484 insertions, 0 deletions

diff --git a/drivers/spi/spi-bcm63xx-hsspi.c b/drivers/spi/spi-bcm63xx-hsspi.c
new file mode 100644
index 000000000000..bc8d848d33b7
--- /dev/null
+++ b/drivers/spi/spi-bcm63xx-hsspi.c
@@ -0,0 +1,484 @@
+/*
+ * 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/workqueue.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_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;
+
+	__raw_writel(0 << MODE_CTRL_PREPENDBYTE_CNT_SHIFT |
+		     2 << MODE_CTRL_MULTIDATA_WR_STRT_SHIFT |
+		     2 << MODE_CTRL_MULTIDATA_RD_STRT_SHIFT | 0xff,
+		     bs->regs + HSSPI_PROFILE_MODE_CTRL_REG(chip_select));
+
+	while (pending > 0) {
+		int curr_step = min_t(int, step_size, pending);
+
+		init_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_request_and_ioremap(dev, res_mem);
+	if (IS_ERR(regs))
+		return PTR_ERR(regs);
+
+	clk = clk_get(dev, "hsspi");
+
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
+	rate = clk_get_rate(clk);
+	if (!rate) {
+		ret = -EINVAL;
+		goto out_put_clk;
+	}
+
+	clk_prepare_enable(clk);
+
+	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);
+
+	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;
+	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 = spi_register_master(master);
+	if (ret)
+		goto out_put_master;
+
+	return 0;
+
+out_put_master:
+	spi_master_put(master);
+out_disable_clk:
+	clk_disable_unprepare(clk);
+out_put_clk:
+	clk_put(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);
+
+	spi_unregister_master(master);
+
+	/* reset the hardware and block queue progress */
+	__raw_writel(0, bs->regs + HSSPI_INT_MASK_REG);
+	clk_disable_unprepare(bs->clk);
+	clk_put(bs->clk);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM
+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(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);
+
+	clk_enable(bs->clk);
+	spi_master_resume(master);
+
+	return 0;
+}
+
+static const struct dev_pm_ops bcm63xx_hsspi_pm_ops = {
+	.suspend	= bcm63xx_hsspi_suspend,
+	.resume		= bcm63xx_hsspi_resume,
+};
+
+#define BCM63XX_HSSPI_PM_OPS	(&bcm63xx_hsspi_pm_ops)
+#else
+#define BCM63XX_HSSPI_PM_OPS	NULL
+#endif
+
+
+
+static struct platform_driver bcm63xx_hsspi_driver = {
+	.driver = {
+		.name	= "bcm63xx-hsspi",
+		.owner	= THIS_MODULE,
+		.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");