spi: microchip-core-qspi: Add support for microchip fpga qspi controllers

Add a driver for Microchip FPGA QSPI controllers. This driver also
supports "hard" QSPI controllers on Polarfire SoC.

Signed-off-by: Naga Sureshkumar Relli <nagasuresh.relli@microchip.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20220808064603.1174906-4-nagasuresh.relli@microchip.com
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 600 insertions, 0 deletions

diff --git a/drivers/spi/spi-microchip-core-qspi.c b/drivers/spi/spi-microchip-core-qspi.c
new file mode 100644
index 000000000000..19a6a46829f6
--- /dev/null
+++ b/drivers/spi/spi-microchip-core-qspi.c
@@ -0,0 +1,600 @@
+// SPDX-License-Identifier: (GPL-2.0)
+/*
+ * Microchip coreQSPI QSPI controller driver
+ *
+ * Copyright (C) 2018-2022 Microchip Technology Inc. and its subsidiaries
+ *
+ * Author: Naga Sureshkumar Relli <nagasuresh.relli@microchip.com>
+ *
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/spi-mem.h>
+
+/*
+ * QSPI Control register mask defines
+ */
+#define CONTROL_ENABLE		BIT(0)
+#define CONTROL_MASTER		BIT(1)
+#define CONTROL_XIP		BIT(2)
+#define CONTROL_XIPADDR		BIT(3)
+#define CONTROL_CLKIDLE		BIT(10)
+#define CONTROL_SAMPLE_MASK	GENMASK(12, 11)
+#define CONTROL_MODE0		BIT(13)
+#define CONTROL_MODE12_MASK	GENMASK(15, 14)
+#define CONTROL_MODE12_EX_RO	BIT(14)
+#define CONTROL_MODE12_EX_RW	BIT(15)
+#define CONTROL_MODE12_FULL	GENMASK(15, 14)
+#define CONTROL_FLAGSX4		BIT(16)
+#define CONTROL_CLKRATE_MASK	GENMASK(27, 24)
+#define CONTROL_CLKRATE_SHIFT	24
+
+/*
+ * QSPI Frames register mask defines
+ */
+#define FRAMES_TOTALBYTES_MASK	GENMASK(15, 0)
+#define FRAMES_CMDBYTES_MASK	GENMASK(24, 16)
+#define FRAMES_CMDBYTES_SHIFT	16
+#define FRAMES_SHIFT		25
+#define FRAMES_IDLE_MASK	GENMASK(29, 26)
+#define FRAMES_IDLE_SHIFT	26
+#define FRAMES_FLAGBYTE		BIT(30)
+#define FRAMES_FLAGWORD		BIT(31)
+
+/*
+ * QSPI Interrupt Enable register mask defines
+ */
+#define IEN_TXDONE		BIT(0)
+#define IEN_RXDONE		BIT(1)
+#define IEN_RXAVAILABLE		BIT(2)
+#define IEN_TXAVAILABLE		BIT(3)
+#define IEN_RXFIFOEMPTY		BIT(4)
+#define IEN_TXFIFOFULL		BIT(5)
+
+/*
+ * QSPI Status register mask defines
+ */
+#define STATUS_TXDONE		BIT(0)
+#define STATUS_RXDONE		BIT(1)
+#define STATUS_RXAVAILABLE	BIT(2)
+#define STATUS_TXAVAILABLE	BIT(3)
+#define STATUS_RXFIFOEMPTY	BIT(4)
+#define STATUS_TXFIFOFULL	BIT(5)
+#define STATUS_READY		BIT(7)
+#define STATUS_FLAGSX4		BIT(8)
+#define STATUS_MASK		GENMASK(8, 0)
+
+#define BYTESUPPER_MASK		GENMASK(31, 16)
+#define BYTESLOWER_MASK		GENMASK(15, 0)
+
+#define MAX_DIVIDER		16
+#define MIN_DIVIDER		0
+#define MAX_DATA_CMD_LEN	256
+
+/* QSPI ready time out value */
+#define TIMEOUT_MS		500
+
+/*
+ * QSPI Register offsets.
+ */
+#define REG_CONTROL		(0x00)
+#define REG_FRAMES		(0x04)
+#define REG_IEN			(0x0c)
+#define REG_STATUS		(0x10)
+#define REG_DIRECT_ACCESS	(0x14)
+#define REG_UPPER_ACCESS	(0x18)
+#define REG_RX_DATA		(0x40)
+#define REG_TX_DATA		(0x44)
+#define REG_X4_RX_DATA		(0x48)
+#define REG_X4_TX_DATA		(0x4c)
+#define REG_FRAMESUP		(0x50)
+
+/**
+ * struct mchp_coreqspi - Defines qspi driver instance
+ * @regs:              Virtual address of the QSPI controller registers
+ * @clk:               QSPI Operating clock
+ * @data_completion:   completion structure
+ * @op_lock:           lock access to the device
+ * @txbuf:             TX buffer
+ * @rxbuf:             RX buffer
+ * @irq:               IRQ number
+ * @tx_len:            Number of bytes left to transfer
+ * @rx_len:            Number of bytes left to receive
+ */
+struct mchp_coreqspi {
+	void __iomem *regs;
+	struct clk *clk;
+	struct completion data_completion;
+	struct mutex op_lock; /* lock access to the device */
+	u8 *txbuf;
+	u8 *rxbuf;
+	int irq;
+	int tx_len;
+	int rx_len;
+};
+
+static int mchp_coreqspi_set_mode(struct mchp_coreqspi *qspi, const struct spi_mem_op *op)
+{
+	u32 control = readl_relaxed(qspi->regs + REG_CONTROL);
+
+	/*
+	 * The operating mode can be configured based on the command that needs to be send.
+	 * bits[15:14]: Sets whether multiple bit SPI operates in normal, extended or full modes.
+	 *		00: Normal (single DQ0 TX and single DQ1 RX lines)
+	 *		01: Extended RO (command and address bytes on DQ0 only)
+	 *		10: Extended RW (command byte on DQ0 only)
+	 *		11: Full. (command and address are on all DQ lines)
+	 * bit[13]:	Sets whether multiple bit SPI uses 2 or 4 bits of data
+	 *		0: 2-bits (BSPI)
+	 *		1: 4-bits (QSPI)
+	 */
+	if (op->data.buswidth == 4 || op->data.buswidth == 2) {
+		control &= ~CONTROL_MODE12_MASK;
+		if (op->cmd.buswidth == 1 && (op->addr.buswidth == 1 || op->addr.buswidth == 0))
+			control |= CONTROL_MODE12_EX_RO;
+		else if (op->cmd.buswidth == 1)
+			control |= CONTROL_MODE12_EX_RW;
+		else
+			control |= CONTROL_MODE12_FULL;
+
+		control |= CONTROL_MODE0;
+	} else {
+		control &= ~(CONTROL_MODE12_MASK |
+			     CONTROL_MODE0);
+	}
+
+	writel_relaxed(control, qspi->regs + REG_CONTROL);
+
+	return 0;
+}
+
+static inline void mchp_coreqspi_read_op(struct mchp_coreqspi *qspi)
+{
+	u32 control, data;
+
+	if (!qspi->rx_len)
+		return;
+
+	control = readl_relaxed(qspi->regs + REG_CONTROL);
+
+	/*
+	 * Read 4-bytes from the SPI FIFO in single transaction and then read
+	 * the reamaining data byte wise.
+	 */
+	control |= CONTROL_FLAGSX4;
+	writel_relaxed(control, qspi->regs + REG_CONTROL);
+
+	while (qspi->rx_len >= 4) {
+		while (readl_relaxed(qspi->regs + REG_STATUS) & STATUS_RXFIFOEMPTY)
+			;
+		data = readl_relaxed(qspi->regs + REG_X4_RX_DATA);
+		*(u32 *)qspi->rxbuf = data;
+		qspi->rxbuf += 4;
+		qspi->rx_len -= 4;
+	}
+
+	control &= ~CONTROL_FLAGSX4;
+	writel_relaxed(control, qspi->regs + REG_CONTROL);
+
+	while (qspi->rx_len--) {
+		while (readl_relaxed(qspi->regs + REG_STATUS) & STATUS_RXFIFOEMPTY)
+			;
+		data = readl_relaxed(qspi->regs + REG_RX_DATA);
+		*qspi->rxbuf++ = (data & 0xFF);
+	}
+}
+
+static inline void mchp_coreqspi_write_op(struct mchp_coreqspi *qspi, bool word)
+{
+	u32 control, data;
+
+	control = readl_relaxed(qspi->regs + REG_CONTROL);
+	control |= CONTROL_FLAGSX4;
+	writel_relaxed(control, qspi->regs + REG_CONTROL);
+
+	while (qspi->tx_len >= 4) {
+		while (readl_relaxed(qspi->regs + REG_STATUS) & STATUS_TXFIFOFULL)
+			;
+		data = *(u32 *)qspi->txbuf;
+		qspi->txbuf += 4;
+		qspi->tx_len -= 4;
+		writel_relaxed(data, qspi->regs + REG_X4_TX_DATA);
+	}
+
+	control &= ~CONTROL_FLAGSX4;
+	writel_relaxed(control, qspi->regs + REG_CONTROL);
+
+	while (qspi->tx_len--) {
+		while (readl_relaxed(qspi->regs + REG_STATUS) & STATUS_TXFIFOFULL)
+			;
+		data =  *qspi->txbuf++;
+		writel_relaxed(data, qspi->regs + REG_TX_DATA);
+	}
+}
+
+static void mchp_coreqspi_enable_ints(struct mchp_coreqspi *qspi)
+{
+	u32 mask = IEN_TXDONE |
+		   IEN_RXDONE |
+		   IEN_RXAVAILABLE;
+
+	writel_relaxed(mask, qspi->regs + REG_IEN);
+}
+
+static void mchp_coreqspi_disable_ints(struct mchp_coreqspi *qspi)
+{
+	writel_relaxed(0, qspi->regs + REG_IEN);
+}
+
+static irqreturn_t mchp_coreqspi_isr(int irq, void *dev_id)
+{
+	struct mchp_coreqspi *qspi = (struct mchp_coreqspi *)dev_id;
+	irqreturn_t ret = IRQ_NONE;
+	int intfield = readl_relaxed(qspi->regs + REG_STATUS) & STATUS_MASK;
+
+	if (intfield == 0)
+		return ret;
+
+	if (intfield & IEN_TXDONE) {
+		writel_relaxed(IEN_TXDONE, qspi->regs + REG_STATUS);
+		ret = IRQ_HANDLED;
+	}
+
+	if (intfield & IEN_RXAVAILABLE) {
+		writel_relaxed(IEN_RXAVAILABLE, qspi->regs + REG_STATUS);
+		mchp_coreqspi_read_op(qspi);
+		ret = IRQ_HANDLED;
+	}
+
+	if (intfield & IEN_RXDONE) {
+		writel_relaxed(IEN_RXDONE, qspi->regs + REG_STATUS);
+		complete(&qspi->data_completion);
+		ret = IRQ_HANDLED;
+	}
+
+	return ret;
+}
+
+static int mchp_coreqspi_setup_clock(struct mchp_coreqspi *qspi, struct spi_device *spi)
+{
+	unsigned long clk_hz;
+	u32 control, baud_rate_val = 0;
+
+	clk_hz = clk_get_rate(qspi->clk);
+	if (!clk_hz)
+		return -EINVAL;
+
+	baud_rate_val = DIV_ROUND_UP(clk_hz, 2 * spi->max_speed_hz);
+	if (baud_rate_val > MAX_DIVIDER || baud_rate_val < MIN_DIVIDER) {
+		dev_err(&spi->dev,
+			"could not configure the clock for spi clock %d Hz & system clock %ld Hz\n",
+			spi->max_speed_hz, clk_hz);
+		return -EINVAL;
+	}
+
+	control = readl_relaxed(qspi->regs + REG_CONTROL);
+	control |= baud_rate_val << CONTROL_CLKRATE_SHIFT;
+	writel_relaxed(control, qspi->regs + REG_CONTROL);
+	control = readl_relaxed(qspi->regs + REG_CONTROL);
+
+	if ((spi->mode & SPI_CPOL) && (spi->mode & SPI_CPHA))
+		control |= CONTROL_CLKIDLE;
+	else
+		control &= ~CONTROL_CLKIDLE;
+
+	writel_relaxed(control, qspi->regs + REG_CONTROL);
+
+	return 0;
+}
+
+static int mchp_coreqspi_setup_op(struct spi_device *spi_dev)
+{
+	struct spi_controller *ctlr = spi_dev->master;
+	struct mchp_coreqspi *qspi = spi_controller_get_devdata(ctlr);
+	u32 control = readl_relaxed(qspi->regs + REG_CONTROL);
+
+	control |= (CONTROL_MASTER | CONTROL_ENABLE);
+	control &= ~CONTROL_CLKIDLE;
+	writel_relaxed(control, qspi->regs + REG_CONTROL);
+
+	return 0;
+}
+
+static inline void mchp_coreqspi_config_op(struct mchp_coreqspi *qspi, const struct spi_mem_op *op)
+{
+	u32 idle_cycles = 0;
+	int total_bytes, cmd_bytes, frames, ctrl;
+
+	cmd_bytes = op->cmd.nbytes + op->addr.nbytes;
+	total_bytes = cmd_bytes + op->data.nbytes;
+
+	/*
+	 * As per the coreQSPI IP spec,the number of command and data bytes are
+	 * controlled by the frames register for each SPI sequence. This supports
+	 * the SPI flash memory read and writes sequences as below. so configure
+	 * the cmd and total bytes accordingly.
+	 * ---------------------------------------------------------------------
+	 * TOTAL BYTES  |  CMD BYTES | What happens                             |
+	 * ______________________________________________________________________
+	 *              |            |                                          |
+	 *     1        |   1        | The SPI core will transmit a single byte |
+	 *              |            | and receive data is discarded            |
+	 *              |            |                                          |
+	 *     1        |   0        | The SPI core will transmit a single byte |
+	 *              |            | and return a single byte                 |
+	 *              |            |                                          |
+	 *     10       |   4        | The SPI core will transmit 4 command     |
+	 *              |            | bytes discarding the receive data and    |
+	 *              |            | transmits 6 dummy bytes returning the 6  |
+	 *              |            | received bytes and return a single byte  |
+	 *              |            |                                          |
+	 *     10       |   10       | The SPI core will transmit 10 command    |
+	 *              |            |                                          |
+	 *     10       |    0       | The SPI core will transmit 10 command    |
+	 *              |            | bytes and returning 10 received bytes    |
+	 * ______________________________________________________________________
+	 */
+	if (!(op->data.dir == SPI_MEM_DATA_IN))
+		cmd_bytes = total_bytes;
+
+	frames = total_bytes & BYTESUPPER_MASK;
+	writel_relaxed(frames, qspi->regs + REG_FRAMESUP);
+	frames = total_bytes & BYTESLOWER_MASK;
+	frames |= cmd_bytes << FRAMES_CMDBYTES_SHIFT;
+
+	if (op->dummy.buswidth)
+		idle_cycles = op->dummy.nbytes * 8 / op->dummy.buswidth;
+
+	frames |= idle_cycles << FRAMES_IDLE_SHIFT;
+	ctrl = readl_relaxed(qspi->regs + REG_CONTROL);
+
+	if (ctrl & CONTROL_MODE12_MASK)
+		frames |= (1 << FRAMES_SHIFT);
+
+	frames |= FRAMES_FLAGWORD;
+	writel_relaxed(frames, qspi->regs + REG_FRAMES);
+}
+
+static int mchp_qspi_wait_for_ready(struct spi_mem *mem)
+{
+	struct mchp_coreqspi *qspi = spi_controller_get_devdata
+				    (mem->spi->master);
+	u32 status;
+	int ret;
+
+	ret = readl_poll_timeout(qspi->regs + REG_STATUS, status,
+				 (status & STATUS_READY), 0,
+				 TIMEOUT_MS);
+	if (ret) {
+		dev_err(&mem->spi->dev,
+			"Timeout waiting on QSPI ready.\n");
+		return -ETIMEDOUT;
+	}
+
+	return ret;
+}
+
+static int mchp_coreqspi_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
+{
+	struct mchp_coreqspi *qspi = spi_controller_get_devdata
+				    (mem->spi->master);
+	u32 address = op->addr.val;
+	u8 opcode = op->cmd.opcode;
+	u8 opaddr[5];
+	int err, i;
+
+	mutex_lock(&qspi->op_lock);
+	err = mchp_qspi_wait_for_ready(mem);
+	if (err)
+		goto error;
+
+	err = mchp_coreqspi_setup_clock(qspi, mem->spi);
+	if (err)
+		goto error;
+
+	err = mchp_coreqspi_set_mode(qspi, op);
+	if (err)
+		goto error;
+
+	reinit_completion(&qspi->data_completion);
+	mchp_coreqspi_config_op(qspi, op);
+	if (op->cmd.opcode) {
+		qspi->txbuf = &opcode;
+		qspi->rxbuf = NULL;
+		qspi->tx_len = op->cmd.nbytes;
+		qspi->rx_len = 0;
+		mchp_coreqspi_write_op(qspi, false);
+	}
+
+	qspi->txbuf = &opaddr[0];
+	if (op->addr.nbytes) {
+		for (i = 0; i < op->addr.nbytes; i++)
+			qspi->txbuf[i] = address >> (8 * (op->addr.nbytes - i - 1));
+
+		qspi->rxbuf = NULL;
+		qspi->tx_len = op->addr.nbytes;
+		qspi->rx_len = 0;
+		mchp_coreqspi_write_op(qspi, false);
+	}
+
+	if (op->data.nbytes) {
+		if (op->data.dir == SPI_MEM_DATA_OUT) {
+			qspi->txbuf = (u8 *)op->data.buf.out;
+			qspi->rxbuf = NULL;
+			qspi->rx_len = 0;
+			qspi->tx_len = op->data.nbytes;
+			mchp_coreqspi_write_op(qspi, true);
+		} else {
+			qspi->txbuf = NULL;
+			qspi->rxbuf = (u8 *)op->data.buf.in;
+			qspi->rx_len = op->data.nbytes;
+			qspi->tx_len = 0;
+		}
+	}
+
+	mchp_coreqspi_enable_ints(qspi);
+
+	if (!wait_for_completion_timeout(&qspi->data_completion, msecs_to_jiffies(1000)))
+		err = -ETIMEDOUT;
+
+error:
+	mutex_unlock(&qspi->op_lock);
+	mchp_coreqspi_disable_ints(qspi);
+
+	return err;
+}
+
+static bool mchp_coreqspi_supports_op(struct spi_mem *mem, const struct spi_mem_op *op)
+{
+	if (!spi_mem_default_supports_op(mem, op))
+		return false;
+
+	if ((op->data.buswidth == 4 || op->data.buswidth == 2) &&
+	    (op->cmd.buswidth == 1 && (op->addr.buswidth == 1 || op->addr.buswidth == 0))) {
+		/*
+		 * If the command and address are on DQ0 only, then this
+		 * controller doesn't support sending data on dual and
+		 * quad lines. but it supports reading data on dual and
+		 * quad lines with same configuration as command and
+		 * address on DQ0.
+		 * i.e. The control register[15:13] :EX_RO(read only) is
+		 * meant only for the command and address are on DQ0 but
+		 * not to write data, it is just to read.
+		 * Ex: 0x34h is Quad Load Program Data which is not
+		 * supported. Then the spi-mem layer will iterate over
+		 * each command and it will chose the supported one.
+		 */
+		if (op->data.dir == SPI_MEM_DATA_OUT)
+			return false;
+	}
+
+	return true;
+}
+
+static int mchp_coreqspi_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
+{
+	if (op->data.dir == SPI_MEM_DATA_OUT || op->data.dir == SPI_MEM_DATA_IN) {
+		if (op->data.nbytes > MAX_DATA_CMD_LEN)
+			op->data.nbytes = MAX_DATA_CMD_LEN;
+	}
+
+	return 0;
+}
+
+static const struct spi_controller_mem_ops mchp_coreqspi_mem_ops = {
+	.adjust_op_size = mchp_coreqspi_adjust_op_size,
+	.supports_op = mchp_coreqspi_supports_op,
+	.exec_op = mchp_coreqspi_exec_op,
+};
+
+static int mchp_coreqspi_probe(struct platform_device *pdev)
+{
+	struct spi_controller *ctlr;
+	struct mchp_coreqspi *qspi;
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	int ret;
+
+	ctlr = devm_spi_alloc_master(&pdev->dev, sizeof(*qspi));
+	if (!ctlr)
+		return dev_err_probe(&pdev->dev, -ENOMEM,
+				     "unable to allocate master for QSPI controller\n");
+
+	qspi = spi_controller_get_devdata(ctlr);
+	platform_set_drvdata(pdev, qspi);
+
+	qspi->regs = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(qspi->regs))
+		return dev_err_probe(&pdev->dev, PTR_ERR(qspi->regs),
+				     "failed to map registers\n");
+
+	qspi->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(qspi->clk))
+		return dev_err_probe(&pdev->dev, PTR_ERR(qspi->clk),
+				     "could not get clock\n");
+
+	ret = clk_prepare_enable(qspi->clk);
+	if (ret)
+		return dev_err_probe(&pdev->dev, ret,
+				     "failed to enable clock\n");
+
+	init_completion(&qspi->data_completion);
+	mutex_init(&qspi->op_lock);
+
+	qspi->irq = platform_get_irq(pdev, 0);
+	if (qspi->irq < 0) {
+		ret = qspi->irq;
+		goto out;
+	}
+
+	ret = devm_request_irq(&pdev->dev, qspi->irq, mchp_coreqspi_isr,
+			       IRQF_SHARED, pdev->name, qspi);
+	if (ret) {
+		dev_err(&pdev->dev, "request_irq failed %d\n", ret);
+		goto out;
+	}
+
+	ctlr->bits_per_word_mask = SPI_BPW_MASK(8);
+	ctlr->mem_ops = &mchp_coreqspi_mem_ops;
+	ctlr->setup = mchp_coreqspi_setup_op;
+	ctlr->mode_bits = SPI_CPOL | SPI_CPHA | SPI_RX_DUAL | SPI_RX_QUAD |
+			  SPI_TX_DUAL | SPI_TX_QUAD;
+	ctlr->dev.of_node = np;
+
+	ret = devm_spi_register_controller(&pdev->dev, ctlr);
+	if (ret) {
+		dev_err_probe(&pdev->dev, ret,
+			      "spi_register_controller failed\n");
+		goto out;
+	}
+
+	return 0;
+
+out:
+	clk_disable_unprepare(qspi->clk);
+
+	return ret;
+}
+
+static int mchp_coreqspi_remove(struct platform_device *pdev)
+{
+	struct mchp_coreqspi *qspi = platform_get_drvdata(pdev);
+	u32 control = readl_relaxed(qspi->regs + REG_CONTROL);
+
+	mchp_coreqspi_disable_ints(qspi);
+	control &= ~CONTROL_ENABLE;
+	writel_relaxed(control, qspi->regs + REG_CONTROL);
+	clk_disable_unprepare(qspi->clk);
+
+	return 0;
+}
+
+static const struct of_device_id mchp_coreqspi_of_match[] = {
+	{ .compatible = "microchip,coreqspi-rtl-v2" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, mchp_coreqspi_of_match);
+
+static struct platform_driver mchp_coreqspi_driver = {
+	.probe = mchp_coreqspi_probe,
+	.driver = {
+		.name = "microchip,coreqspi",
+		.of_match_table = mchp_coreqspi_of_match,
+	},
+	.remove = mchp_coreqspi_remove,
+};
+module_platform_driver(mchp_coreqspi_driver);
+
+MODULE_AUTHOR("Naga Sureshkumar Relli <nagasuresh.relli@microchip.com");
+MODULE_DESCRIPTION("Microchip coreQSPI QSPI controller driver");
+MODULE_LICENSE("GPL");