[mirror_ubuntu-artful-kernel.git] / drivers / spi / xilinx_spi.c

/*
 * 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.

 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/mfd/core.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_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_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)
#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;
	struct resource mem; /* phys mem */
	void __iomem	*regs;	/* virt. address of the control registers */

	u32		irq;

	u8 *rx_ptr;		/* pointer in the Tx buffer */
	const u8 *tx_ptr;	/* pointer in the Rx buffer */
	int remaining_bytes;	/* the number of bytes left to transfer */
	u8 bits_per_word;
	unsigned int (*read_fn) (void __iomem *);
	void (*write_fn) (u32, void __iomem *);
	void (*tx_fn) (struct xilinx_spi *);
	void (*rx_fn) (struct xilinx_spi *);
};

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 xspi_tx8(struct xilinx_spi *xspi)
{
	xspi->write_fn(*xspi->tx_ptr, xspi->regs + XSPI_TXD_OFFSET);
	xspi->tx_ptr++;
}

static void xspi_tx16(struct xilinx_spi *xspi)
{
	xspi->write_fn(*(u16 *)(xspi->tx_ptr), xspi->regs + XSPI_TXD_OFFSET);
	xspi->tx_ptr += 2;
}

static void xspi_tx32(struct xilinx_spi *xspi)
{
	xspi->write_fn(*(u32 *)(xspi->tx_ptr), xspi->regs + XSPI_TXD_OFFSET);
	xspi->tx_ptr += 4;
}

static void xspi_rx8(struct xilinx_spi *xspi)
{
	u32 data = xspi->read_fn(xspi->regs + XSPI_RXD_OFFSET);
	if (xspi->rx_ptr) {
		*xspi->rx_ptr = data & 0xff;
		xspi->rx_ptr++;
	}
}

static void xspi_rx16(struct xilinx_spi *xspi)
{
	u32 data = xspi->read_fn(xspi->regs + XSPI_RXD_OFFSET);
	if (xspi->rx_ptr) {
		*(u16 *)(xspi->rx_ptr) = data & 0xffff;
		xspi->rx_ptr += 2;
	}
}

static void xspi_rx32(struct xilinx_spi *xspi)
{
	u32 data = xspi->read_fn(xspi->regs + XSPI_RXD_OFFSET);
	if (xspi->rx_ptr) {
		*(u32 *)(xspi->rx_ptr) = data;
		xspi->rx_ptr += 4;
	}
}

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);
	/* Disable all the interrupts just in case */
	xspi->write_fn(0, regs_base + XIPIF_V123B_IIER_OFFSET);
	/* Enable the global IPIF interrupt */
	xspi->write_fn(XIPIF_V123B_GINTR_ENABLE,
		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_TRANS_INHIBIT | 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);

	if (is_on == BITBANG_CS_INACTIVE) {
		/* Deselect the slave on the SPI bus */
		xspi->write_fn(0xffff, xspi->regs + XSPI_SSR_OFFSET);
	} else if (is_on == BITBANG_CS_ACTIVE) {
		/* Set the SPI clock phase and polarity */
		u16 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;
		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)
		 */

		/* Activate the chip select */
		xspi->write_fn(~(0x0001 << spi->chip_select),
			xspi->regs + XSPI_SSR_OFFSET);
	}
}

/* spi_bitbang requires custom setup_transfer() to be defined if there is a
 * custom txrx_bufs(). We have nothing to setup here as the SPI IP block
 * supports 8 or 16 bits per word which cannot be changed in software.
 * SPI clock can't be changed in software either.
 * Check for correct bits per word. Chip select delay calculations could be
 * added here as soon as bitbang_work() can be made aware of the delay value.
 */
static int xilinx_spi_setup_transfer(struct spi_device *spi,
		struct spi_transfer *t)
{
	struct xilinx_spi *xspi = spi_master_get_devdata(spi->master);
	u8 bits_per_word;

	bits_per_word = (t && t->bits_per_word)
			 ? t->bits_per_word : spi->bits_per_word;
	if (bits_per_word != xspi->bits_per_word) {
		dev_err(&spi->dev, "%s, unsupported bits_per_word=%d\n",
			__func__, bits_per_word);
		return -EINVAL;
	}

	return 0;
}

static int xilinx_spi_setup(struct spi_device *spi)
{
	/* always return 0, we can not check the number of bits.
	 * There are cases when SPI setup is called before any driver is
	 * there, in that case the SPI core defaults to 8 bits, which we
	 * do not support in some cases. But if we return an error, the
	 * SPI device would not be registered and no driver can get hold of it
	 * When the driver is there, it will call SPI setup again with the
	 * correct number of bits per transfer.
	 * If a driver setups with the wrong bit number, it will fail when
	 * it tries to do a transfer
	 */
	return 0;
}

static void xilinx_spi_fill_tx_fifo(struct xilinx_spi *xspi)
{
	u8 sr;

	/* Fill the Tx FIFO with as many bytes as possible */
	sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
	while ((sr & XSPI_SR_TX_FULL_MASK) == 0 && xspi->remaining_bytes > 0) {
		if (xspi->tx_ptr)
			xspi->tx_fn(xspi);
		else
			xspi->write_fn(0, xspi->regs + XSPI_TXD_OFFSET);
		xspi->remaining_bytes -= xspi->bits_per_word / 8;
		sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
	}
}

static int xilinx_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
{
	struct xilinx_spi *xspi = spi_master_get_devdata(spi->master);
	u32 ipif_ier;
	u16 cr;

	/* We get here with transmitter inhibited */

	xspi->tx_ptr = t->tx_buf;
	xspi->rx_ptr = t->rx_buf;
	xspi->remaining_bytes = t->len;
	INIT_COMPLETION(xspi->done);

	xilinx_spi_fill_tx_fifo(xspi);

	/* Enable the transmit empty interrupt, which we use to determine
	 * progress on the transmission.
	 */
	ipif_ier = xspi->read_fn(xspi->regs + XIPIF_V123B_IIER_OFFSET);
	xspi->write_fn(ipif_ier | XSPI_INTR_TX_EMPTY,
		xspi->regs + XIPIF_V123B_IIER_OFFSET);

	/* Start the transfer by not inhibiting the transmitter any longer */
	cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET) &
		~XSPI_CR_TRANS_INHIBIT;
	xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET);

	wait_for_completion(&xspi->done);

	/* Disable the transmit empty interrupt */
	xspi->write_fn(ipif_ier, xspi->regs + XIPIF_V123B_IIER_OFFSET);

	return t->len - xspi->remaining_bytes;
}


/* 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 */
		u16 cr;
		u8 sr;

		/* 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.
		 */
		cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET);
		xspi->write_fn(cr | XSPI_CR_TRANS_INHIBIT,
			xspi->regs + XSPI_CR_OFFSET);

		/* Read out all the data from the Rx FIFO */
		sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
		while ((sr & XSPI_SR_RX_EMPTY_MASK) == 0) {
			xspi->rx_fn(xspi);
			sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
		}

		/* See if there is more data to send */
		if (xspi->remaining_bytes > 0) {
			xilinx_spi_fill_tx_fifo(xspi);
			/* Start the transfer by not inhibiting the
			 * transmitter any longer
			 */
			xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET);
		} else {
			/* No more data to send.
			 * Indicate the transfer is completed.
			 */
			complete(&xspi->done);
		}
	}

	return IRQ_HANDLED;
}

static const struct of_device_id xilinx_spi_of_match[] = {
	{ .compatible = "xlnx,xps-spi-2.00.a", },
	{ .compatible = "xlnx,xps-spi-2.00.b", },
	{}
};
MODULE_DEVICE_TABLE(of, xilinx_spi_of_match);

struct spi_master *xilinx_spi_init(struct device *dev, struct resource *mem,
	u32 irq, s16 bus_num, int num_cs, int little_endian, int bits_per_word)
{
	struct spi_master *master;
	struct xilinx_spi *xspi;
	int ret;

	master = spi_alloc_master(dev, sizeof(struct xilinx_spi));
	if (!master)
		return NULL;

	/* the spi->mode bits understood by this driver: */
	master->mode_bits = SPI_CPOL | SPI_CPHA;

	xspi = spi_master_get_devdata(master);
	xspi->bitbang.master = spi_master_get(master);
	xspi->bitbang.chipselect = xilinx_spi_chipselect;
	xspi->bitbang.setup_transfer = xilinx_spi_setup_transfer;
	xspi->bitbang.txrx_bufs = xilinx_spi_txrx_bufs;
	xspi->bitbang.master->setup = xilinx_spi_setup;
	init_completion(&xspi->done);

	if (!request_mem_region(mem->start, resource_size(mem),
		XILINX_SPI_NAME))
		goto put_master;

	xspi->regs = ioremap(mem->start, resource_size(mem));
	if (xspi->regs == NULL) {
		dev_warn(dev, "ioremap failure\n");
		goto map_failed;
	}

	master->bus_num = bus_num;
	master->num_chipselect = num_cs;
	master->dev.of_node = dev->of_node;

	xspi->mem = *mem;
	xspi->irq = irq;
	if (little_endian) {
		xspi->read_fn = xspi_read32;
		xspi->write_fn = xspi_write32;
	} else {
		xspi->read_fn = xspi_read32_be;
		xspi->write_fn = xspi_write32_be;
	}
	xspi->bits_per_word = bits_per_word;
	if (xspi->bits_per_word == 8) {
		xspi->tx_fn = xspi_tx8;
		xspi->rx_fn = xspi_rx8;
	} else if (xspi->bits_per_word == 16) {
		xspi->tx_fn = xspi_tx16;
		xspi->rx_fn = xspi_rx16;
	} else if (xspi->bits_per_word == 32) {
		xspi->tx_fn = xspi_tx32;
		xspi->rx_fn = xspi_rx32;
	} else
		goto unmap_io;


	/* SPI controller initializations */
	xspi_init_hw(xspi);

	/* Register for SPI Interrupt */
	ret = request_irq(xspi->irq, xilinx_spi_irq, 0, XILINX_SPI_NAME, xspi);
	if (ret)
		goto unmap_io;

	ret = spi_bitbang_start(&xspi->bitbang);
	if (ret) {
		dev_err(dev, "spi_bitbang_start FAILED\n");
		goto free_irq;
	}

	dev_info(dev, "at 0x%08llX mapped to 0x%p, irq=%d\n",
		(unsigned long long)mem->start, xspi->regs, xspi->irq);
	return master;

free_irq:
	free_irq(xspi->irq, xspi);
unmap_io:
	iounmap(xspi->regs);
map_failed:
	release_mem_region(mem->start, resource_size(mem));
put_master:
	spi_master_put(master);
	return NULL;
}
EXPORT_SYMBOL(xilinx_spi_init);

void xilinx_spi_deinit(struct spi_master *master)
{
	struct xilinx_spi *xspi;

	xspi = spi_master_get_devdata(master);

	spi_bitbang_stop(&xspi->bitbang);
	free_irq(xspi->irq, xspi);
	iounmap(xspi->regs);

	release_mem_region(xspi->mem.start, resource_size(&xspi->mem));
	spi_master_put(xspi->bitbang.master);
}
EXPORT_SYMBOL(xilinx_spi_deinit);

static int __devinit xilinx_spi_probe(struct platform_device *dev)
{
	struct xspi_platform_data *pdata;
	struct resource *r;
	int irq, num_cs = 0, little_endian = 0, bits_per_word = 8;
	struct spi_master *master;
	u8 i;

	pdata = mfd_get_data(dev);
	if (pdata) {
		num_cs = pdata->num_chipselect;
		little_endian = pdata->little_endian;
		bits_per_word = pdata->bits_per_word;
	}

#ifdef CONFIG_OF
	if (dev->dev.of_node) {
		const __be32 *prop;
		int len;

		/* number of slave select bits is required */
		prop = of_get_property(dev->dev.of_node, "xlnx,num-ss-bits",
				       &len);
		if (prop && len >= sizeof(*prop))
			num_cs = __be32_to_cpup(prop);
	}
#endif

	if (!num_cs) {
		dev_err(&dev->dev, "Missing slave select configuration data\n");
		return -EINVAL;
	}


	r = platform_get_resource(dev, IORESOURCE_MEM, 0);
	if (!r)
		return -ENODEV;

	irq = platform_get_irq(dev, 0);
	if (irq < 0)
		return -ENXIO;

	master = xilinx_spi_init(&dev->dev, r, irq, dev->id, num_cs,
				 little_endian, bits_per_word);
	if (!master)
		return -ENODEV;

	if (pdata) {
		for (i = 0; i < pdata->num_devices; i++)
			spi_new_device(master, pdata->devices + i);
	}

	platform_set_drvdata(dev, master);
	return 0;
}

static int __devexit xilinx_spi_remove(struct platform_device *dev)
{
	xilinx_spi_deinit(platform_get_drvdata(dev));
	platform_set_drvdata(dev, 0);

	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 = __devexit_p(xilinx_spi_remove),
	.driver = {
		.name = XILINX_SPI_NAME,
		.owner = THIS_MODULE,
		.of_match_table = xilinx_spi_of_match,
	},
};

static int __init xilinx_spi_pltfm_init(void)
{
	return platform_driver_register(&xilinx_spi_driver);
}
module_init(xilinx_spi_pltfm_init);

static void __exit xilinx_spi_pltfm_exit(void)
{
	platform_driver_unregister(&xilinx_spi_driver);
}
module_exit(xilinx_spi_pltfm_exit);

MODULE_AUTHOR("MontaVista Software, Inc. <source@mvista.com>");
MODULE_DESCRIPTION("Xilinx SPI driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
ae918c02	1	/*
ae918c02 AK	2	* Xilinx SPI controller driver (master mode only)
	3	*
	4	* Author: MontaVista Software, Inc.
	5	* source@mvista.com
	6	*
8fd8821b GL	7	* Copyright (c) 2010 Secret Lab Technologies, Ltd.
	8	* Copyright (c) 2009 Intel Corporation
	9	* 2002-2007 (c) MontaVista Software, Inc.
	10
	11	* This program is free software; you can redistribute it and/or modify
	12	* it under the terms of the GNU General Public License version 2 as
	13	* published by the Free Software Foundation.
ae918c02 AK	14	*/
	15
	16	#include <linux/module.h>
	17	#include <linux/init.h>
	18	#include <linux/interrupt.h>
eae6cb31	19	#include <linux/of.h>
8fd8821b	20	#include <linux/platform_device.h>
e46dccff	21	#include <linux/mfd/core.h>
ae918c02 AK	22	#include <linux/spi/spi.h>
ae918c02 AK	23	#include <linux/spi/spi_bitbang.h>
d5af91a1	24	#include <linux/spi/xilinx_spi.h>
eae6cb31	25	#include <linux/io.h>
d5af91a1	26
fc3ba952	27	#define XILINX_SPI_NAME "xilinx_spi"
ae918c02 AK	28
	29	/* Register definitions as per "OPB Serial Peripheral Interface (SPI) (v1.00e)
	30	* Product Specification", DS464
	31	*/
c9da2e12	32	#define XSPI_CR_OFFSET 0x60 /* Control Register */
ae918c02 AK	33
	34	#define XSPI_CR_ENABLE 0x02
	35	#define XSPI_CR_MASTER_MODE 0x04
	36	#define XSPI_CR_CPOL 0x08
	37	#define XSPI_CR_CPHA 0x10
	38	#define XSPI_CR_MODE_MASK (XSPI_CR_CPHA \| XSPI_CR_CPOL)
	39	#define XSPI_CR_TXFIFO_RESET 0x20
	40	#define XSPI_CR_RXFIFO_RESET 0x40
	41	#define XSPI_CR_MANUAL_SSELECT 0x80
	42	#define XSPI_CR_TRANS_INHIBIT 0x100
c9da2e12	43	#define XSPI_CR_LSB_FIRST 0x200
ae918c02	44
c9da2e12	45	#define XSPI_SR_OFFSET 0x64 /* Status Register */
ae918c02 AK	46
	47	#define XSPI_SR_RX_EMPTY_MASK 0x01 /* Receive FIFO is empty */
	48	#define XSPI_SR_RX_FULL_MASK 0x02 /* Receive FIFO is full */
	49	#define XSPI_SR_TX_EMPTY_MASK 0x04 /* Transmit FIFO is empty */
	50	#define XSPI_SR_TX_FULL_MASK 0x08 /* Transmit FIFO is full */
	51	#define XSPI_SR_MODE_FAULT_MASK 0x10 /* Mode fault error */
	52
c9da2e12 RR	53	#define XSPI_TXD_OFFSET 0x68 /* Data Transmit Register */
c9da2e12 RR	54	#define XSPI_RXD_OFFSET 0x6c /* Data Receive Register */
ae918c02 AK	55
	56	#define XSPI_SSR_OFFSET 0x70 /* 32-bit Slave Select Register */
	57
	58	/* Register definitions as per "OPB IPIF (v3.01c) Product Specification", DS414
	59	* IPIF registers are 32 bit
	60	*/
	61	#define XIPIF_V123B_DGIER_OFFSET 0x1c /* IPIF global int enable reg */
	62	#define XIPIF_V123B_GINTR_ENABLE 0x80000000
	63
	64	#define XIPIF_V123B_IISR_OFFSET 0x20 /* IPIF interrupt status reg */
	65	#define XIPIF_V123B_IIER_OFFSET 0x28 /* IPIF interrupt enable reg */
	66
	67	#define XSPI_INTR_MODE_FAULT 0x01 /* Mode fault error */
	68	#define XSPI_INTR_SLAVE_MODE_FAULT 0x02 /* Selected as slave while
	69	* disabled */
	70	#define XSPI_INTR_TX_EMPTY 0x04 /* TxFIFO is empty */
	71	#define XSPI_INTR_TX_UNDERRUN 0x08 /* TxFIFO was underrun */
	72	#define XSPI_INTR_RX_FULL 0x10 /* RxFIFO is full */
	73	#define XSPI_INTR_RX_OVERRUN 0x20 /* RxFIFO was overrun */
c9da2e12	74	#define XSPI_INTR_TX_HALF_EMPTY 0x40 /* TxFIFO is half empty */
ae918c02 AK	75
	76	#define XIPIF_V123B_RESETR_OFFSET 0x40 /* IPIF reset register */
	77	#define XIPIF_V123B_RESET_MASK 0x0a /* the value to write */
	78
	79	struct xilinx_spi {
	80	/* bitbang has to be first */
	81	struct spi_bitbang bitbang;
	82	struct completion done;
d5af91a1	83	struct resource mem; /* phys mem */
ae918c02 AK	84	void __iomem regs; / virt. address of the control registers */
	85
	86	u32 irq;
	87
ae918c02 AK	88	u8 rx_ptr; / pointer in the Tx buffer */
	89	const u8 tx_ptr; / pointer in the Rx buffer */
	90	int remaining_bytes; /* the number of bytes left to transfer */
c9da2e12	91	u8 bits_per_word;
86fc5935 RR	92	unsigned int (read_fn) (void __iomem );
86fc5935 RR	93	void (write_fn) (u32, void __iomem );
c9da2e12 RR	94	void (tx_fn) (struct xilinx_spi );
c9da2e12 RR	95	void (rx_fn) (struct xilinx_spi );
ae918c02 AK	96	};
ae918c02 AK	97
97782149 PM	98	static void xspi_write32(u32 val, void __iomem *addr)
	99	{
	100	iowrite32(val, addr);
	101	}
	102
	103	static unsigned int xspi_read32(void __iomem *addr)
	104	{
	105	return ioread32(addr);
	106	}
	107
	108	static void xspi_write32_be(u32 val, void __iomem *addr)
	109	{
	110	iowrite32be(val, addr);
	111	}
	112
	113	static unsigned int xspi_read32_be(void __iomem *addr)
	114	{
	115	return ioread32be(addr);
	116	}
	117
c9da2e12 RR	118	static void xspi_tx8(struct xilinx_spi *xspi)
	119	{
	120	xspi->write_fn(*xspi->tx_ptr, xspi->regs + XSPI_TXD_OFFSET);
	121	xspi->tx_ptr++;
	122	}
	123
	124	static void xspi_tx16(struct xilinx_spi *xspi)
	125	{
	126	xspi->write_fn((u16 )(xspi->tx_ptr), xspi->regs + XSPI_TXD_OFFSET);
	127	xspi->tx_ptr += 2;
	128	}
	129
	130	static void xspi_tx32(struct xilinx_spi *xspi)
	131	{
	132	xspi->write_fn((u32 )(xspi->tx_ptr), xspi->regs + XSPI_TXD_OFFSET);
	133	xspi->tx_ptr += 4;
	134	}
	135
	136	static void xspi_rx8(struct xilinx_spi *xspi)
	137	{
	138	u32 data = xspi->read_fn(xspi->regs + XSPI_RXD_OFFSET);
	139	if (xspi->rx_ptr) {
	140	*xspi->rx_ptr = data & 0xff;
	141	xspi->rx_ptr++;
	142	}
	143	}
	144
	145	static void xspi_rx16(struct xilinx_spi *xspi)
	146	{
	147	u32 data = xspi->read_fn(xspi->regs + XSPI_RXD_OFFSET);
	148	if (xspi->rx_ptr) {
	149	(u16 )(xspi->rx_ptr) = data & 0xffff;
	150	xspi->rx_ptr += 2;
	151	}
	152	}
	153
	154	static void xspi_rx32(struct xilinx_spi *xspi)
	155	{
	156	u32 data = xspi->read_fn(xspi->regs + XSPI_RXD_OFFSET);
	157	if (xspi->rx_ptr) {
	158	(u32 )(xspi->rx_ptr) = data;
	159	xspi->rx_ptr += 4;
	160	}
	161	}
	162
86fc5935	163	static void xspi_init_hw(struct xilinx_spi *xspi)
ae918c02	164	{
86fc5935 RR	165	void __iomem *regs_base = xspi->regs;
86fc5935 RR	166
ae918c02	167	/* Reset the SPI device */
86fc5935 RR	168	xspi->write_fn(XIPIF_V123B_RESET_MASK,
86fc5935 RR	169	regs_base + XIPIF_V123B_RESETR_OFFSET);
ae918c02	170	/* Disable all the interrupts just in case */
86fc5935	171	xspi->write_fn(0, regs_base + XIPIF_V123B_IIER_OFFSET);
ae918c02	172	/* Enable the global IPIF interrupt */
86fc5935 RR	173	xspi->write_fn(XIPIF_V123B_GINTR_ENABLE,
86fc5935 RR	174	regs_base + XIPIF_V123B_DGIER_OFFSET);
ae918c02	175	/* Deselect the slave on the SPI bus */
86fc5935	176	xspi->write_fn(0xffff, regs_base + XSPI_SSR_OFFSET);
ae918c02 AK	177	/* Disable the transmitter, enable Manual Slave Select Assertion,
ae918c02 AK	178	* put SPI controller into master mode, and enable it */
86fc5935	179	xspi->write_fn(XSPI_CR_TRANS_INHIBIT \| XSPI_CR_MANUAL_SSELECT \|
c9da2e12 RR	180	XSPI_CR_MASTER_MODE \| XSPI_CR_ENABLE \| XSPI_CR_TXFIFO_RESET \|
c9da2e12 RR	181	XSPI_CR_RXFIFO_RESET, regs_base + XSPI_CR_OFFSET);
ae918c02 AK	182	}
	183
	184	static void xilinx_spi_chipselect(struct spi_device *spi, int is_on)
	185	{
	186	struct xilinx_spi *xspi = spi_master_get_devdata(spi->master);
	187
	188	if (is_on == BITBANG_CS_INACTIVE) {
	189	/* Deselect the slave on the SPI bus */
86fc5935	190	xspi->write_fn(0xffff, xspi->regs + XSPI_SSR_OFFSET);
ae918c02 AK	191	} else if (is_on == BITBANG_CS_ACTIVE) {
ae918c02 AK	192	/* Set the SPI clock phase and polarity */
86fc5935	193	u16 cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET)
ae918c02 AK	194	& ~XSPI_CR_MODE_MASK;
	195	if (spi->mode & SPI_CPHA)
	196	cr \|= XSPI_CR_CPHA;
	197	if (spi->mode & SPI_CPOL)
	198	cr \|= XSPI_CR_CPOL;
86fc5935	199	xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET);
ae918c02 AK	200
	201	/* We do not check spi->max_speed_hz here as the SPI clock
	202	* frequency is not software programmable (the IP block design
	203	* parameter)
	204	*/
	205
	206	/* Activate the chip select */
86fc5935 RR	207	xspi->write_fn(~(0x0001 << spi->chip_select),
86fc5935 RR	208	xspi->regs + XSPI_SSR_OFFSET);
ae918c02 AK	209	}
	210	}
	211
	212	/* spi_bitbang requires custom setup_transfer() to be defined if there is a
	213	* custom txrx_bufs(). We have nothing to setup here as the SPI IP block
c9da2e12 RR	214	* supports 8 or 16 bits per word which cannot be changed in software.
	215	* SPI clock can't be changed in software either.
	216	* Check for correct bits per word. Chip select delay calculations could be
ae918c02 AK	217	* added here as soon as bitbang_work() can be made aware of the delay value.
	218	*/
	219	static int xilinx_spi_setup_transfer(struct spi_device *spi,
	220	struct spi_transfer *t)
	221	{
c9da2e12	222	struct xilinx_spi *xspi = spi_master_get_devdata(spi->master);
ae918c02	223	u8 bits_per_word;
ae918c02	224
1a8d3b77 JL	225	bits_per_word = (t && t->bits_per_word)
1a8d3b77 JL	226	? t->bits_per_word : spi->bits_per_word;
c9da2e12	227	if (bits_per_word != xspi->bits_per_word) {
ae918c02	228	dev_err(&spi->dev, "%s, unsupported bits_per_word=%d\n",
b687d2a8	229	__func__, bits_per_word);
ae918c02 AK	230	return -EINVAL;
	231	}
	232
ae918c02 AK	233	return 0;
	234	}
	235
ae918c02 AK	236	static int xilinx_spi_setup(struct spi_device *spi)
ae918c02 AK	237	{
c9da2e12 RR	238	/* always return 0, we can not check the number of bits.
	239	* There are cases when SPI setup is called before any driver is
	240	* there, in that case the SPI core defaults to 8 bits, which we
	241	* do not support in some cases. But if we return an error, the
	242	* SPI device would not be registered and no driver can get hold of it
	243	* When the driver is there, it will call SPI setup again with the
	244	* correct number of bits per transfer.
	245	* If a driver setups with the wrong bit number, it will fail when
	246	* it tries to do a transfer
	247	*/
ae918c02 AK	248	return 0;
	249	}
	250
	251	static void xilinx_spi_fill_tx_fifo(struct xilinx_spi *xspi)
	252	{
	253	u8 sr;
	254
	255	/* Fill the Tx FIFO with as many bytes as possible */
86fc5935	256	sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
ae918c02	257	while ((sr & XSPI_SR_TX_FULL_MASK) == 0 && xspi->remaining_bytes > 0) {
86fc5935	258	if (xspi->tx_ptr)
c9da2e12	259	xspi->tx_fn(xspi);
86fc5935 RR	260	else
86fc5935 RR	261	xspi->write_fn(0, xspi->regs + XSPI_TXD_OFFSET);
c9da2e12	262	xspi->remaining_bytes -= xspi->bits_per_word / 8;
86fc5935	263	sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
ae918c02 AK	264	}
	265	}
	266
	267	static int xilinx_spi_txrx_bufs(struct spi_device spi, struct spi_transfer t)
	268	{
	269	struct xilinx_spi *xspi = spi_master_get_devdata(spi->master);
	270	u32 ipif_ier;
	271	u16 cr;
	272
	273	/* We get here with transmitter inhibited */
	274
	275	xspi->tx_ptr = t->tx_buf;
	276	xspi->rx_ptr = t->rx_buf;
	277	xspi->remaining_bytes = t->len;
	278	INIT_COMPLETION(xspi->done);
	279
	280	xilinx_spi_fill_tx_fifo(xspi);
	281
	282	/* Enable the transmit empty interrupt, which we use to determine
	283	* progress on the transmission.
	284	*/
86fc5935 RR	285	ipif_ier = xspi->read_fn(xspi->regs + XIPIF_V123B_IIER_OFFSET);
	286	xspi->write_fn(ipif_ier \| XSPI_INTR_TX_EMPTY,
	287	xspi->regs + XIPIF_V123B_IIER_OFFSET);
ae918c02 AK	288
ae918c02 AK	289	/* Start the transfer by not inhibiting the transmitter any longer */
86fc5935 RR	290	cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET) &
	291	~XSPI_CR_TRANS_INHIBIT;
	292	xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET);
ae918c02 AK	293
	294	wait_for_completion(&xspi->done);
	295
	296	/* Disable the transmit empty interrupt */
86fc5935	297	xspi->write_fn(ipif_ier, xspi->regs + XIPIF_V123B_IIER_OFFSET);
ae918c02 AK	298
	299	return t->len - xspi->remaining_bytes;
	300	}
	301
	302
	303	/* This driver supports single master mode only. Hence Tx FIFO Empty
	304	* is the only interrupt we care about.
	305	* Receive FIFO Overrun, Transmit FIFO Underrun, Mode Fault, and Slave Mode
	306	* Fault are not to happen.
	307	*/
	308	static irqreturn_t xilinx_spi_irq(int irq, void *dev_id)
	309	{
	310	struct xilinx_spi *xspi = dev_id;
	311	u32 ipif_isr;
	312
	313	/* Get the IPIF interrupts, and clear them immediately */
86fc5935 RR	314	ipif_isr = xspi->read_fn(xspi->regs + XIPIF_V123B_IISR_OFFSET);
86fc5935 RR	315	xspi->write_fn(ipif_isr, xspi->regs + XIPIF_V123B_IISR_OFFSET);
ae918c02 AK	316
	317	if (ipif_isr & XSPI_INTR_TX_EMPTY) { /* Transmission completed */
	318	u16 cr;
	319	u8 sr;
	320
	321	/* A transmit has just completed. Process received data and
	322	* check for more data to transmit. Always inhibit the
	323	* transmitter while the Isr refills the transmit register/FIFO,
	324	* or make sure it is stopped if we're done.
	325	*/
86fc5935 RR	326	cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET);
	327	xspi->write_fn(cr \| XSPI_CR_TRANS_INHIBIT,
	328	xspi->regs + XSPI_CR_OFFSET);
ae918c02 AK	329
ae918c02 AK	330	/* Read out all the data from the Rx FIFO */
86fc5935	331	sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
ae918c02	332	while ((sr & XSPI_SR_RX_EMPTY_MASK) == 0) {
c9da2e12	333	xspi->rx_fn(xspi);
86fc5935	334	sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
ae918c02 AK	335	}
	336
	337	/* See if there is more data to send */
	338	if (xspi->remaining_bytes > 0) {
	339	xilinx_spi_fill_tx_fifo(xspi);
	340	/* Start the transfer by not inhibiting the
	341	* transmitter any longer
	342	*/
86fc5935	343	xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET);
ae918c02 AK	344	} else {
	345	/* No more data to send.
	346	* Indicate the transfer is completed.
	347	*/
	348	complete(&xspi->done);
	349	}
	350	}
	351
	352	return IRQ_HANDLED;
	353	}
	354
eae6cb31 GL	355	static const struct of_device_id xilinx_spi_of_match[] = {
	356	{ .compatible = "xlnx,xps-spi-2.00.a", },
	357	{ .compatible = "xlnx,xps-spi-2.00.b", },
	358	{}
	359	};
	360	MODULE_DEVICE_TABLE(of, xilinx_spi_of_match);
eae6cb31	361
d5af91a1	362	struct spi_master xilinx_spi_init(struct device dev, struct resource *mem,
91565c40	363	u32 irq, s16 bus_num, int num_cs, int little_endian, int bits_per_word)
ae918c02	364	{
ae918c02 AK	365	struct spi_master *master;
ae918c02 AK	366	struct xilinx_spi *xspi;
d5af91a1	367	int ret;
ae918c02	368
d5af91a1 RR	369	master = spi_alloc_master(dev, sizeof(struct xilinx_spi));
	370	if (!master)
	371	return NULL;
ae918c02	372
e7db06b5 DB	373	/* the spi->mode bits understood by this driver: */
	374	master->mode_bits = SPI_CPOL \| SPI_CPHA;
	375
ae918c02 AK	376	xspi = spi_master_get_devdata(master);
	377	xspi->bitbang.master = spi_master_get(master);
	378	xspi->bitbang.chipselect = xilinx_spi_chipselect;
	379	xspi->bitbang.setup_transfer = xilinx_spi_setup_transfer;
	380	xspi->bitbang.txrx_bufs = xilinx_spi_txrx_bufs;
	381	xspi->bitbang.master->setup = xilinx_spi_setup;
	382	init_completion(&xspi->done);
	383
d5af91a1 RR	384	if (!request_mem_region(mem->start, resource_size(mem),
d5af91a1 RR	385	XILINX_SPI_NAME))
ae918c02	386	goto put_master;
ae918c02	387
d5af91a1	388	xspi->regs = ioremap(mem->start, resource_size(mem));
ae918c02	389	if (xspi->regs == NULL) {
d5af91a1 RR	390	dev_warn(dev, "ioremap failure\n");
d5af91a1 RR	391	goto map_failed;
ae918c02 AK	392	}
ae918c02 AK	393
d5af91a1	394	master->bus_num = bus_num;
91565c40	395	master->num_chipselect = num_cs;
12b15e83	396	master->dev.of_node = dev->of_node;
ae918c02	397
d5af91a1 RR	398	xspi->mem = *mem;
d5af91a1 RR	399	xspi->irq = irq;
91565c40	400	if (little_endian) {
97782149 PM	401	xspi->read_fn = xspi_read32;
97782149 PM	402	xspi->write_fn = xspi_write32;
86fc5935	403	} else {
97782149 PM	404	xspi->read_fn = xspi_read32_be;
97782149 PM	405	xspi->write_fn = xspi_write32_be;
86fc5935	406	}
91565c40	407	xspi->bits_per_word = bits_per_word;
c9da2e12 RR	408	if (xspi->bits_per_word == 8) {
	409	xspi->tx_fn = xspi_tx8;
	410	xspi->rx_fn = xspi_rx8;
	411	} else if (xspi->bits_per_word == 16) {
	412	xspi->tx_fn = xspi_tx16;
	413	xspi->rx_fn = xspi_rx16;
	414	} else if (xspi->bits_per_word == 32) {
	415	xspi->tx_fn = xspi_tx32;
	416	xspi->rx_fn = xspi_rx32;
	417	} else
	418	goto unmap_io;
	419
ae918c02 AK	420
ae918c02 AK	421	/* SPI controller initializations */
86fc5935	422	xspi_init_hw(xspi);
ae918c02 AK	423
ae918c02 AK	424	/* Register for SPI Interrupt */
d5af91a1 RR	425	ret = request_irq(xspi->irq, xilinx_spi_irq, 0, XILINX_SPI_NAME, xspi);
d5af91a1 RR	426	if (ret)
ae918c02 AK	427	goto unmap_io;
ae918c02 AK	428
d5af91a1 RR	429	ret = spi_bitbang_start(&xspi->bitbang);
	430	if (ret) {
	431	dev_err(dev, "spi_bitbang_start FAILED\n");
ae918c02 AK	432	goto free_irq;
	433	}
	434
920712af GL	435	dev_info(dev, "at 0x%08llX mapped to 0x%p, irq=%d\n",
920712af GL	436	(unsigned long long)mem->start, xspi->regs, xspi->irq);
d5af91a1	437	return master;
ae918c02 AK	438
	439	free_irq:
	440	free_irq(xspi->irq, xspi);
	441	unmap_io:
	442	iounmap(xspi->regs);
d5af91a1 RR	443	map_failed:
d5af91a1 RR	444	release_mem_region(mem->start, resource_size(mem));
ae918c02 AK	445	put_master:
ae918c02 AK	446	spi_master_put(master);
d5af91a1	447	return NULL;
ae918c02	448	}
d5af91a1	449	EXPORT_SYMBOL(xilinx_spi_init);
ae918c02	450
d5af91a1	451	void xilinx_spi_deinit(struct spi_master *master)
ae918c02 AK	452	{
ae918c02 AK	453	struct xilinx_spi *xspi;
ae918c02	454
ae918c02 AK	455	xspi = spi_master_get_devdata(master);
	456
	457	spi_bitbang_stop(&xspi->bitbang);
	458	free_irq(xspi->irq, xspi);
	459	iounmap(xspi->regs);
ff82c587	460
d5af91a1 RR	461	release_mem_region(xspi->mem.start, resource_size(&xspi->mem));
d5af91a1 RR	462	spi_master_put(xspi->bitbang.master);
ae918c02	463	}
d5af91a1	464	EXPORT_SYMBOL(xilinx_spi_deinit);
ae918c02	465
8fd8821b GL	466	static int __devinit xilinx_spi_probe(struct platform_device *dev)
	467	{
	468	struct xspi_platform_data *pdata;
	469	struct resource *r;
eae6cb31	470	int irq, num_cs = 0, little_endian = 0, bits_per_word = 8;
8fd8821b GL	471	struct spi_master *master;
	472	u8 i;
	473
e46dccff	474	pdata = mfd_get_data(dev);
eae6cb31 GL	475	if (pdata) {
	476	num_cs = pdata->num_chipselect;
	477	little_endian = pdata->little_endian;
	478	bits_per_word = pdata->bits_per_word;
	479	}
	480
	481	#ifdef CONFIG_OF
	482	if (dev->dev.of_node) {
	483	const __be32 *prop;
	484	int len;
	485
	486	/* number of slave select bits is required */
	487	prop = of_get_property(dev->dev.of_node, "xlnx,num-ss-bits",
	488	&len);
	489	if (prop && len >= sizeof(*prop))
	490	num_cs = __be32_to_cpup(prop);
	491	}
	492	#endif
	493
	494	if (!num_cs) {
	495	dev_err(&dev->dev, "Missing slave select configuration data\n");
	496	return -EINVAL;
	497	}
	498
8fd8821b GL	499
	500	r = platform_get_resource(dev, IORESOURCE_MEM, 0);
	501	if (!r)
	502	return -ENODEV;
	503
	504	irq = platform_get_irq(dev, 0);
	505	if (irq < 0)
	506	return -ENXIO;
	507
eae6cb31 GL	508	master = xilinx_spi_init(&dev->dev, r, irq, dev->id, num_cs,
eae6cb31 GL	509	little_endian, bits_per_word);
8fd8821b GL	510	if (!master)
	511	return -ENODEV;
	512
eae6cb31 GL	513	if (pdata) {
	514	for (i = 0; i < pdata->num_devices; i++)
	515	spi_new_device(master, pdata->devices + i);
	516	}
8fd8821b GL	517
	518	platform_set_drvdata(dev, master);
	519	return 0;
	520	}
	521
	522	static int __devexit xilinx_spi_remove(struct platform_device *dev)
	523	{
	524	xilinx_spi_deinit(platform_get_drvdata(dev));
	525	platform_set_drvdata(dev, 0);
	526
	527	return 0;
	528	}
	529
	530	/* work with hotplug and coldplug */
	531	MODULE_ALIAS("platform:" XILINX_SPI_NAME);
	532
	533	static struct platform_driver xilinx_spi_driver = {
	534	.probe = xilinx_spi_probe,
	535	.remove = __devexit_p(xilinx_spi_remove),
	536	.driver = {
	537	.name = XILINX_SPI_NAME,
	538	.owner = THIS_MODULE,
eae6cb31	539	.of_match_table = xilinx_spi_of_match,
8fd8821b GL	540	},
	541	};
	542
	543	static int __init xilinx_spi_pltfm_init(void)
	544	{
	545	return platform_driver_register(&xilinx_spi_driver);
	546	}
	547	module_init(xilinx_spi_pltfm_init);
	548
	549	static void __exit xilinx_spi_pltfm_exit(void)
	550	{
	551	platform_driver_unregister(&xilinx_spi_driver);
	552	}
	553	module_exit(xilinx_spi_pltfm_exit);
	554
ae918c02 AK	555	MODULE_AUTHOR("MontaVista Software, Inc. <source@mvista.com>");
	556	MODULE_DESCRIPTION("Xilinx SPI driver");
	557	MODULE_LICENSE("GPL");