/*
* 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/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 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 = dev->dev.platform_data;
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 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 = xilinx_spi_remove,
.driver = {
.name = XILINX_SPI_NAME,
.owner = THIS_MODULE,
.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");
