1 files changed, 543 insertions, 0 deletions

diff --git a/drivers/spi/spi-xilinx.c b/drivers/spi/spi-xilinx.c
new file mode 100644
index 000000000..523edfdf5
--- /dev/null
+++ b/drivers/spi/spi-xilinx.c
@@ -0,0 +1,543 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Xilinx SPI controller driver (master mode only)
+ *
+ * Author: MontaVista Software, Inc.
+ *	source@mvista.com
+ *
+ * Copyright (c) 2010 Secret Lab Technologies, Ltd.
+ * Copyright (c) 2009 Intel Corporation
+ * 2002-2007 (c) MontaVista Software, Inc.
+
+ */
+
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/spi_bitbang.h>
+#include <linux/spi/xilinx_spi.h>
+#include <linux/io.h>
+
+#define XILINX_SPI_MAX_CS	32
+
+#define XILINX_SPI_NAME "xilinx_spi"
+
+/* Register definitions as per "OPB Serial Peripheral Interface (SPI) (v1.00e)
+ * Product Specification", DS464
+ */
+#define XSPI_CR_OFFSET		0x60	/* Control Register */
+
+#define XSPI_CR_LOOP		0x01
+#define XSPI_CR_ENABLE		0x02
+#define XSPI_CR_MASTER_MODE	0x04
+#define XSPI_CR_CPOL		0x08
+#define XSPI_CR_CPHA		0x10
+#define XSPI_CR_MODE_MASK	(XSPI_CR_CPHA | XSPI_CR_CPOL | \
+				 XSPI_CR_LSB_FIRST | XSPI_CR_LOOP)
+#define XSPI_CR_TXFIFO_RESET	0x20
+#define XSPI_CR_RXFIFO_RESET	0x40
+#define XSPI_CR_MANUAL_SSELECT	0x80
+#define XSPI_CR_TRANS_INHIBIT	0x100
+#define XSPI_CR_LSB_FIRST	0x200
+
+#define XSPI_SR_OFFSET		0x64	/* Status Register */
+
+#define XSPI_SR_RX_EMPTY_MASK	0x01	/* Receive FIFO is empty */
+#define XSPI_SR_RX_FULL_MASK	0x02	/* Receive FIFO is full */
+#define XSPI_SR_TX_EMPTY_MASK	0x04	/* Transmit FIFO is empty */
+#define XSPI_SR_TX_FULL_MASK	0x08	/* Transmit FIFO is full */
+#define XSPI_SR_MODE_FAULT_MASK	0x10	/* Mode fault error */
+
+#define XSPI_TXD_OFFSET		0x68	/* Data Transmit Register */
+#define XSPI_RXD_OFFSET		0x6c	/* Data Receive Register */
+
+#define XSPI_SSR_OFFSET		0x70	/* 32-bit Slave Select Register */
+
+/* Register definitions as per "OPB IPIF (v3.01c) Product Specification", DS414
+ * IPIF registers are 32 bit
+ */
+#define XIPIF_V123B_DGIER_OFFSET	0x1c	/* IPIF global int enable reg */
+#define XIPIF_V123B_GINTR_ENABLE	0x80000000
+
+#define XIPIF_V123B_IISR_OFFSET		0x20	/* IPIF interrupt status reg */
+#define XIPIF_V123B_IIER_OFFSET		0x28	/* IPIF interrupt enable reg */
+
+#define XSPI_INTR_MODE_FAULT		0x01	/* Mode fault error */
+#define XSPI_INTR_SLAVE_MODE_FAULT	0x02	/* Selected as slave while
+						 * disabled */
+#define XSPI_INTR_TX_EMPTY		0x04	/* TxFIFO is empty */
+#define XSPI_INTR_TX_UNDERRUN		0x08	/* TxFIFO was underrun */
+#define XSPI_INTR_RX_FULL		0x10	/* RxFIFO is full */
+#define XSPI_INTR_RX_OVERRUN		0x20	/* RxFIFO was overrun */
+#define XSPI_INTR_TX_HALF_EMPTY		0x40	/* TxFIFO is half empty */
+
+#define XIPIF_V123B_RESETR_OFFSET	0x40	/* IPIF reset register */
+#define XIPIF_V123B_RESET_MASK		0x0a	/* the value to write */
+
+struct xilinx_spi {
+	/* bitbang has to be first */
+	struct spi_bitbang bitbang;
+	struct completion done;
+	void __iomem	*regs;	/* virt. address of the control registers */
+
+	int		irq;
+
+	u8 *rx_ptr;		/* pointer in the Tx buffer */
+	const u8 *tx_ptr;	/* pointer in the Rx buffer */
+	u8 bytes_per_word;
+	int buffer_size;	/* buffer size in words */
+	u32 cs_inactive;	/* Level of the CS pins when inactive*/
+	unsigned int (*read_fn)(void __iomem *);
+	void (*write_fn)(u32, void __iomem *);
+};
+
+static void xspi_write32(u32 val, void __iomem *addr)
+{
+	iowrite32(val, addr);
+}
+
+static unsigned int xspi_read32(void __iomem *addr)
+{
+	return ioread32(addr);
+}
+
+static void xspi_write32_be(u32 val, void __iomem *addr)
+{
+	iowrite32be(val, addr);
+}
+
+static unsigned int xspi_read32_be(void __iomem *addr)
+{
+	return ioread32be(addr);
+}
+
+static void xilinx_spi_tx(struct xilinx_spi *xspi)
+{
+	u32 data = 0;
+
+	if (!xspi->tx_ptr) {
+		xspi->write_fn(0, xspi->regs + XSPI_TXD_OFFSET);
+		return;
+	}
+
+	switch (xspi->bytes_per_word) {
+	case 1:
+		data = *(u8 *)(xspi->tx_ptr);
+		break;
+	case 2:
+		data = *(u16 *)(xspi->tx_ptr);
+		break;
+	case 4:
+		data = *(u32 *)(xspi->tx_ptr);
+		break;
+	}
+
+	xspi->write_fn(data, xspi->regs + XSPI_TXD_OFFSET);
+	xspi->tx_ptr += xspi->bytes_per_word;
+}
+
+static void xilinx_spi_rx(struct xilinx_spi *xspi)
+{
+	u32 data = xspi->read_fn(xspi->regs + XSPI_RXD_OFFSET);
+
+	if (!xspi->rx_ptr)
+		return;
+
+	switch (xspi->bytes_per_word) {
+	case 1:
+		*(u8 *)(xspi->rx_ptr) = data;
+		break;
+	case 2:
+		*(u16 *)(xspi->rx_ptr) = data;
+		break;
+	case 4:
+		*(u32 *)(xspi->rx_ptr) = data;
+		break;
+	}
+
+	xspi->rx_ptr += xspi->bytes_per_word;
+}
+
+static void xspi_init_hw(struct xilinx_spi *xspi)
+{
+	void __iomem *regs_base = xspi->regs;
+
+	/* Reset the SPI device */
+	xspi->write_fn(XIPIF_V123B_RESET_MASK,
+		regs_base + XIPIF_V123B_RESETR_OFFSET);
+	/* Enable the transmit empty interrupt, which we use to determine
+	 * progress on the transmission.
+	 */
+	xspi->write_fn(XSPI_INTR_TX_EMPTY,
+			regs_base + XIPIF_V123B_IIER_OFFSET);
+	/* Disable the global IPIF interrupt */
+	xspi->write_fn(0, regs_base + XIPIF_V123B_DGIER_OFFSET);
+	/* Deselect the slave on the SPI bus */
+	xspi->write_fn(0xffff, regs_base + XSPI_SSR_OFFSET);
+	/* Disable the transmitter, enable Manual Slave Select Assertion,
+	 * put SPI controller into master mode, and enable it */
+	xspi->write_fn(XSPI_CR_MANUAL_SSELECT |	XSPI_CR_MASTER_MODE |
+		XSPI_CR_ENABLE | XSPI_CR_TXFIFO_RESET |	XSPI_CR_RXFIFO_RESET,
+		regs_base + XSPI_CR_OFFSET);
+}
+
+static void xilinx_spi_chipselect(struct spi_device *spi, int is_on)
+{
+	struct xilinx_spi *xspi = spi_master_get_devdata(spi->master);
+	u16 cr;
+	u32 cs;
+
+	if (is_on == BITBANG_CS_INACTIVE) {
+		/* Deselect the slave on the SPI bus */
+		xspi->write_fn(xspi->cs_inactive, xspi->regs + XSPI_SSR_OFFSET);
+		return;
+	}
+
+	/* Set the SPI clock phase and polarity */
+	cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET)	& ~XSPI_CR_MODE_MASK;
+	if (spi->mode & SPI_CPHA)
+		cr |= XSPI_CR_CPHA;
+	if (spi->mode & SPI_CPOL)
+		cr |= XSPI_CR_CPOL;
+	if (spi->mode & SPI_LSB_FIRST)
+		cr |= XSPI_CR_LSB_FIRST;
+	if (spi->mode & SPI_LOOP)
+		cr |= XSPI_CR_LOOP;
+	xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET);
+
+	/* We do not check spi->max_speed_hz here as the SPI clock
+	 * frequency is not software programmable (the IP block design
+	 * parameter)
+	 */
+
+	cs = xspi->cs_inactive;
+	cs ^= BIT(spi->chip_select);
+
+	/* Activate the chip select */
+	xspi->write_fn(cs, xspi->regs + XSPI_SSR_OFFSET);
+}
+
+/* spi_bitbang requires custom setup_transfer() to be defined if there is a
+ * custom txrx_bufs().
+ */
+static int xilinx_spi_setup_transfer(struct spi_device *spi,
+		struct spi_transfer *t)
+{
+	struct xilinx_spi *xspi = spi_master_get_devdata(spi->master);
+
+	if (spi->mode & SPI_CS_HIGH)
+		xspi->cs_inactive &= ~BIT(spi->chip_select);
+	else
+		xspi->cs_inactive |= BIT(spi->chip_select);
+
+	return 0;
+}
+
+static int xilinx_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
+{
+	struct xilinx_spi *xspi = spi_master_get_devdata(spi->master);
+	int remaining_words;	/* the number of words left to transfer */
+	bool use_irq = false;
+	u16 cr = 0;
+
+	/* We get here with transmitter inhibited */
+
+	xspi->tx_ptr = t->tx_buf;
+	xspi->rx_ptr = t->rx_buf;
+	remaining_words = t->len / xspi->bytes_per_word;
+
+	if (xspi->irq >= 0 &&  remaining_words > xspi->buffer_size) {
+		u32 isr;
+		use_irq = true;
+		/* Inhibit irq to avoid spurious irqs on tx_empty*/
+		cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET);
+		xspi->write_fn(cr | XSPI_CR_TRANS_INHIBIT,
+			       xspi->regs + XSPI_CR_OFFSET);
+		/* ACK old irqs (if any) */
+		isr = xspi->read_fn(xspi->regs + XIPIF_V123B_IISR_OFFSET);
+		if (isr)
+			xspi->write_fn(isr,
+				       xspi->regs + XIPIF_V123B_IISR_OFFSET);
+		/* Enable the global IPIF interrupt */
+		xspi->write_fn(XIPIF_V123B_GINTR_ENABLE,
+				xspi->regs + XIPIF_V123B_DGIER_OFFSET);
+		reinit_completion(&xspi->done);
+	}
+
+	while (remaining_words) {
+		int n_words, tx_words, rx_words;
+		u32 sr;
+		int stalled;
+
+		n_words = min(remaining_words, xspi->buffer_size);
+
+		tx_words = n_words;
+		while (tx_words--)
+			xilinx_spi_tx(xspi);
+
+		/* Start the transfer by not inhibiting the transmitter any
+		 * longer
+		 */
+
+		if (use_irq) {
+			xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET);
+			wait_for_completion(&xspi->done);
+			/* A transmit has just completed. Process received data
+			 * and check for more data to transmit. Always inhibit
+			 * the transmitter while the Isr refills the transmit
+			 * register/FIFO, or make sure it is stopped if we're
+			 * done.
+			 */
+			xspi->write_fn(cr | XSPI_CR_TRANS_INHIBIT,
+				       xspi->regs + XSPI_CR_OFFSET);
+			sr = XSPI_SR_TX_EMPTY_MASK;
+		} else
+			sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
+
+		/* Read out all the data from the Rx FIFO */
+		rx_words = n_words;
+		stalled = 10;
+		while (rx_words) {
+			if (rx_words == n_words && !(stalled--) &&
+			    !(sr & XSPI_SR_TX_EMPTY_MASK) &&
+			    (sr & XSPI_SR_RX_EMPTY_MASK)) {
+				dev_err(&spi->dev,
+					"Detected stall. Check C_SPI_MODE and C_SPI_MEMORY\n");
+				xspi_init_hw(xspi);
+				return -EIO;
+			}
+
+			if ((sr & XSPI_SR_TX_EMPTY_MASK) && (rx_words > 1)) {
+				xilinx_spi_rx(xspi);
+				rx_words--;
+				continue;
+			}
+
+			sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
+			if (!(sr & XSPI_SR_RX_EMPTY_MASK)) {
+				xilinx_spi_rx(xspi);
+				rx_words--;
+			}
+		}
+
+		remaining_words -= n_words;
+	}
+
+	if (use_irq) {
+		xspi->write_fn(0, xspi->regs + XIPIF_V123B_DGIER_OFFSET);
+		xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET);
+	}
+
+	return t->len;
+}
+
+
+/* This driver supports single master mode only. Hence Tx FIFO Empty
+ * is the only interrupt we care about.
+ * Receive FIFO Overrun, Transmit FIFO Underrun, Mode Fault, and Slave Mode
+ * Fault are not to happen.
+ */
+static irqreturn_t xilinx_spi_irq(int irq, void *dev_id)
+{
+	struct xilinx_spi *xspi = dev_id;
+	u32 ipif_isr;
+
+	/* Get the IPIF interrupts, and clear them immediately */
+	ipif_isr = xspi->read_fn(xspi->regs + XIPIF_V123B_IISR_OFFSET);
+	xspi->write_fn(ipif_isr, xspi->regs + XIPIF_V123B_IISR_OFFSET);
+
+	if (ipif_isr & XSPI_INTR_TX_EMPTY) {	/* Transmission completed */
+		complete(&xspi->done);
+		return IRQ_HANDLED;
+	}
+
+	return IRQ_NONE;
+}
+
+static int xilinx_spi_find_buffer_size(struct xilinx_spi *xspi)
+{
+	u8 sr;
+	int n_words = 0;
+
+	/*
+	 * Before the buffer_size detection we reset the core
+	 * to make sure we start with a clean state.
+	 */
+	xspi->write_fn(XIPIF_V123B_RESET_MASK,
+		xspi->regs + XIPIF_V123B_RESETR_OFFSET);
+
+	/* Fill the Tx FIFO with as many words as possible */
+	do {
+		xspi->write_fn(0, xspi->regs + XSPI_TXD_OFFSET);
+		sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
+		n_words++;
+	} while (!(sr & XSPI_SR_TX_FULL_MASK));
+
+	return n_words;
+}
+
+static const struct of_device_id xilinx_spi_of_match[] = {
+	{ .compatible = "xlnx,axi-quad-spi-1.00.a", },
+	{ .compatible = "xlnx,xps-spi-2.00.a", },
+	{ .compatible = "xlnx,xps-spi-2.00.b", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, xilinx_spi_of_match);
+
+static int xilinx_spi_probe(struct platform_device *pdev)
+{
+	struct xilinx_spi *xspi;
+	struct xspi_platform_data *pdata;
+	struct resource *res;
+	int ret, num_cs = 0, bits_per_word;
+	struct spi_master *master;
+	u32 tmp;
+	u8 i;
+
+	pdata = dev_get_platdata(&pdev->dev);
+	if (pdata) {
+		num_cs = pdata->num_chipselect;
+		bits_per_word = pdata->bits_per_word;
+	} else {
+		of_property_read_u32(pdev->dev.of_node, "xlnx,num-ss-bits",
+					  &num_cs);
+		ret = of_property_read_u32(pdev->dev.of_node,
+					   "xlnx,num-transfer-bits",
+					   &bits_per_word);
+		if (ret)
+			bits_per_word = 8;
+	}
+
+	if (!num_cs) {
+		dev_err(&pdev->dev,
+			"Missing slave select configuration data\n");
+		return -EINVAL;
+	}
+
+	if (num_cs > XILINX_SPI_MAX_CS) {
+		dev_err(&pdev->dev, "Invalid number of spi slaves\n");
+		return -EINVAL;
+	}
+
+	master = spi_alloc_master(&pdev->dev, sizeof(struct xilinx_spi));
+	if (!master)
+		return -ENODEV;
+
+	/* the spi->mode bits understood by this driver: */
+	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LSB_FIRST | SPI_LOOP |
+			    SPI_CS_HIGH;
+
+	xspi = spi_master_get_devdata(master);
+	xspi->cs_inactive = 0xffffffff;
+	xspi->bitbang.master = master;
+	xspi->bitbang.chipselect = xilinx_spi_chipselect;
+	xspi->bitbang.setup_transfer = xilinx_spi_setup_transfer;
+	xspi->bitbang.txrx_bufs = xilinx_spi_txrx_bufs;
+	init_completion(&xspi->done);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	xspi->regs = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(xspi->regs)) {
+		ret = PTR_ERR(xspi->regs);
+		goto put_master;
+	}
+
+	master->bus_num = pdev->id;
+	master->num_chipselect = num_cs;
+	master->dev.of_node = pdev->dev.of_node;
+
+	/*
+	 * Detect endianess on the IP via loop bit in CR. Detection
+	 * must be done before reset is sent because incorrect reset
+	 * value generates error interrupt.
+	 * Setup little endian helper functions first and try to use them
+	 * and check if bit was correctly setup or not.
+	 */
+	xspi->read_fn = xspi_read32;
+	xspi->write_fn = xspi_write32;
+
+	xspi->write_fn(XSPI_CR_LOOP, xspi->regs + XSPI_CR_OFFSET);
+	tmp = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET);
+	tmp &= XSPI_CR_LOOP;
+	if (tmp != XSPI_CR_LOOP) {
+		xspi->read_fn = xspi_read32_be;
+		xspi->write_fn = xspi_write32_be;
+	}
+
+	master->bits_per_word_mask = SPI_BPW_MASK(bits_per_word);
+	xspi->bytes_per_word = bits_per_word / 8;
+	xspi->buffer_size = xilinx_spi_find_buffer_size(xspi);
+
+	xspi->irq = platform_get_irq(pdev, 0);
+	if (xspi->irq < 0 && xspi->irq != -ENXIO) {
+		ret = xspi->irq;
+		goto put_master;
+	} else if (xspi->irq >= 0) {
+		/* Register for SPI Interrupt */
+		ret = devm_request_irq(&pdev->dev, xspi->irq, xilinx_spi_irq, 0,
+				dev_name(&pdev->dev), xspi);
+		if (ret)
+			goto put_master;
+	}
+
+	/* SPI controller initializations */
+	xspi_init_hw(xspi);
+
+	ret = spi_bitbang_start(&xspi->bitbang);
+	if (ret) {
+		dev_err(&pdev->dev, "spi_bitbang_start FAILED\n");
+		goto put_master;
+	}
+
+	dev_info(&pdev->dev, "at %pR, irq=%d\n", res, xspi->irq);
+
+	if (pdata) {
+		for (i = 0; i < pdata->num_devices; i++)
+			spi_new_device(master, pdata->devices + i);
+	}
+
+	platform_set_drvdata(pdev, master);
+	return 0;
+
+put_master:
+	spi_master_put(master);
+
+	return ret;
+}
+
+static int xilinx_spi_remove(struct platform_device *pdev)
+{
+	struct spi_master *master = platform_get_drvdata(pdev);
+	struct xilinx_spi *xspi = spi_master_get_devdata(master);
+	void __iomem *regs_base = xspi->regs;
+
+	spi_bitbang_stop(&xspi->bitbang);
+
+	/* Disable all the interrupts just in case */
+	xspi->write_fn(0, regs_base + XIPIF_V123B_IIER_OFFSET);
+	/* Disable the global IPIF interrupt */
+	xspi->write_fn(0, regs_base + XIPIF_V123B_DGIER_OFFSET);
+
+	spi_master_put(xspi->bitbang.master);
+
+	return 0;
+}
+
+/* work with hotplug and coldplug */
+MODULE_ALIAS("platform:" XILINX_SPI_NAME);
+
+static struct platform_driver xilinx_spi_driver = {
+	.probe = xilinx_spi_probe,
+	.remove = xilinx_spi_remove,
+	.driver = {
+		.name = XILINX_SPI_NAME,
+		.of_match_table = xilinx_spi_of_match,
+	},
+};
+module_platform_driver(xilinx_spi_driver);
+
+MODULE_AUTHOR("MontaVista Software, Inc. <source@mvista.com>");
+MODULE_DESCRIPTION("Xilinx SPI driver");
+MODULE_LICENSE("GPL");