blob: 6ab4c770022882eacc338a31b345c0d80bc1b541 [file] [log] [blame]
/*
* SPI-Engine SPI controller driver
* Copyright 2015 Analog Devices Inc.
* Author: Lars-Peter Clausen <lars@metafoo.de>
*
* Licensed under the GPL-2.
*/
#include <linux/clk.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/spi/spi.h>
#define SPI_ENGINE_VERSION_MAJOR(x) ((x >> 16) & 0xff)
#define SPI_ENGINE_VERSION_MINOR(x) ((x >> 8) & 0xff)
#define SPI_ENGINE_VERSION_PATCH(x) (x & 0xff)
#define SPI_ENGINE_REG_VERSION 0x00
#define SPI_ENGINE_REG_RESET 0x40
#define SPI_ENGINE_REG_INT_ENABLE 0x80
#define SPI_ENGINE_REG_INT_PENDING 0x84
#define SPI_ENGINE_REG_INT_SOURCE 0x88
#define SPI_ENGINE_REG_SYNC_ID 0xc0
#define SPI_ENGINE_REG_CMD_FIFO_ROOM 0xd0
#define SPI_ENGINE_REG_SDO_FIFO_ROOM 0xd4
#define SPI_ENGINE_REG_SDI_FIFO_LEVEL 0xd8
#define SPI_ENGINE_REG_CMD_FIFO 0xe0
#define SPI_ENGINE_REG_SDO_DATA_FIFO 0xe4
#define SPI_ENGINE_REG_SDI_DATA_FIFO 0xe8
#define SPI_ENGINE_REG_SDI_DATA_FIFO_PEEK 0xec
#define SPI_ENGINE_INT_CMD_ALMOST_EMPTY BIT(0)
#define SPI_ENGINE_INT_SDO_ALMOST_EMPTY BIT(1)
#define SPI_ENGINE_INT_SDI_ALMOST_FULL BIT(2)
#define SPI_ENGINE_INT_SYNC BIT(3)
#define SPI_ENGINE_CONFIG_CPHA BIT(0)
#define SPI_ENGINE_CONFIG_CPOL BIT(1)
#define SPI_ENGINE_CONFIG_3WIRE BIT(2)
#define SPI_ENGINE_INST_TRANSFER 0x0
#define SPI_ENGINE_INST_ASSERT 0x1
#define SPI_ENGINE_INST_WRITE 0x2
#define SPI_ENGINE_INST_MISC 0x3
#define SPI_ENGINE_CMD_REG_CLK_DIV 0x0
#define SPI_ENGINE_CMD_REG_CONFIG 0x1
#define SPI_ENGINE_MISC_SYNC 0x0
#define SPI_ENGINE_MISC_SLEEP 0x1
#define SPI_ENGINE_TRANSFER_WRITE 0x1
#define SPI_ENGINE_TRANSFER_READ 0x2
#define SPI_ENGINE_CMD(inst, arg1, arg2) \
(((inst) << 12) | ((arg1) << 8) | (arg2))
#define SPI_ENGINE_CMD_TRANSFER(flags, n) \
SPI_ENGINE_CMD(SPI_ENGINE_INST_TRANSFER, (flags), (n))
#define SPI_ENGINE_CMD_ASSERT(delay, cs) \
SPI_ENGINE_CMD(SPI_ENGINE_INST_ASSERT, (delay), (cs))
#define SPI_ENGINE_CMD_WRITE(reg, val) \
SPI_ENGINE_CMD(SPI_ENGINE_INST_WRITE, (reg), (val))
#define SPI_ENGINE_CMD_SLEEP(delay) \
SPI_ENGINE_CMD(SPI_ENGINE_INST_MISC, SPI_ENGINE_MISC_SLEEP, (delay))
#define SPI_ENGINE_CMD_SYNC(id) \
SPI_ENGINE_CMD(SPI_ENGINE_INST_MISC, SPI_ENGINE_MISC_SYNC, (id))
struct spi_engine_program {
unsigned int length;
uint16_t instructions[];
};
struct spi_engine {
struct clk *clk;
struct clk *ref_clk;
spinlock_t lock;
void __iomem *base;
struct spi_message *msg;
struct spi_engine_program *p;
unsigned cmd_length;
const uint16_t *cmd_buf;
struct spi_transfer *tx_xfer;
unsigned int tx_length;
const uint8_t *tx_buf;
struct spi_transfer *rx_xfer;
unsigned int rx_length;
uint8_t *rx_buf;
unsigned int sync_id;
unsigned int completed_id;
unsigned int int_enable;
};
static void spi_engine_program_add_cmd(struct spi_engine_program *p,
bool dry, uint16_t cmd)
{
if (!dry)
p->instructions[p->length] = cmd;
p->length++;
}
static unsigned int spi_engine_get_config(struct spi_device *spi)
{
unsigned int config = 0;
if (spi->mode & SPI_CPOL)
config |= SPI_ENGINE_CONFIG_CPOL;
if (spi->mode & SPI_CPHA)
config |= SPI_ENGINE_CONFIG_CPHA;
if (spi->mode & SPI_3WIRE)
config |= SPI_ENGINE_CONFIG_3WIRE;
return config;
}
static unsigned int spi_engine_get_clk_div(struct spi_engine *spi_engine,
struct spi_device *spi, struct spi_transfer *xfer)
{
unsigned int clk_div;
clk_div = DIV_ROUND_UP(clk_get_rate(spi_engine->ref_clk),
xfer->speed_hz * 2);
if (clk_div > 255)
clk_div = 255;
else if (clk_div > 0)
clk_div -= 1;
return clk_div;
}
static void spi_engine_gen_xfer(struct spi_engine_program *p, bool dry,
struct spi_transfer *xfer)
{
unsigned int len = xfer->len;
while (len) {
unsigned int n = min(len, 256U);
unsigned int flags = 0;
if (xfer->tx_buf)
flags |= SPI_ENGINE_TRANSFER_WRITE;
if (xfer->rx_buf)
flags |= SPI_ENGINE_TRANSFER_READ;
spi_engine_program_add_cmd(p, dry,
SPI_ENGINE_CMD_TRANSFER(flags, n - 1));
len -= n;
}
}
static void spi_engine_gen_sleep(struct spi_engine_program *p, bool dry,
struct spi_engine *spi_engine, unsigned int clk_div, unsigned int delay)
{
unsigned int spi_clk = clk_get_rate(spi_engine->ref_clk);
unsigned int t;
if (delay == 0)
return;
t = DIV_ROUND_UP(delay * spi_clk, (clk_div + 1) * 2);
while (t) {
unsigned int n = min(t, 256U);
spi_engine_program_add_cmd(p, dry, SPI_ENGINE_CMD_SLEEP(n - 1));
t -= n;
}
}
static void spi_engine_gen_cs(struct spi_engine_program *p, bool dry,
struct spi_device *spi, bool assert)
{
unsigned int mask = 0xff;
if (assert)
mask ^= BIT(spi->chip_select);
spi_engine_program_add_cmd(p, dry, SPI_ENGINE_CMD_ASSERT(1, mask));
}
static int spi_engine_compile_message(struct spi_engine *spi_engine,
struct spi_message *msg, bool dry, struct spi_engine_program *p)
{
struct spi_device *spi = msg->spi;
struct spi_transfer *xfer;
int clk_div, new_clk_div;
bool cs_change = true;
clk_div = -1;
spi_engine_program_add_cmd(p, dry,
SPI_ENGINE_CMD_WRITE(SPI_ENGINE_CMD_REG_CONFIG,
spi_engine_get_config(spi)));
list_for_each_entry(xfer, &msg->transfers, transfer_list) {
new_clk_div = spi_engine_get_clk_div(spi_engine, spi, xfer);
if (new_clk_div != clk_div) {
clk_div = new_clk_div;
spi_engine_program_add_cmd(p, dry,
SPI_ENGINE_CMD_WRITE(SPI_ENGINE_CMD_REG_CLK_DIV,
clk_div));
}
if (cs_change)
spi_engine_gen_cs(p, dry, spi, true);
spi_engine_gen_xfer(p, dry, xfer);
spi_engine_gen_sleep(p, dry, spi_engine, clk_div,
xfer->delay_usecs);
cs_change = xfer->cs_change;
if (list_is_last(&xfer->transfer_list, &msg->transfers))
cs_change = !cs_change;
if (cs_change)
spi_engine_gen_cs(p, dry, spi, false);
}
return 0;
}
static void spi_engine_xfer_next(struct spi_engine *spi_engine,
struct spi_transfer **_xfer)
{
struct spi_message *msg = spi_engine->msg;
struct spi_transfer *xfer = *_xfer;
if (!xfer) {
xfer = list_first_entry(&msg->transfers,
struct spi_transfer, transfer_list);
} else if (list_is_last(&xfer->transfer_list, &msg->transfers)) {
xfer = NULL;
} else {
xfer = list_next_entry(xfer, transfer_list);
}
*_xfer = xfer;
}
static void spi_engine_tx_next(struct spi_engine *spi_engine)
{
struct spi_transfer *xfer = spi_engine->tx_xfer;
do {
spi_engine_xfer_next(spi_engine, &xfer);
} while (xfer && !xfer->tx_buf);
spi_engine->tx_xfer = xfer;
if (xfer) {
spi_engine->tx_length = xfer->len;
spi_engine->tx_buf = xfer->tx_buf;
} else {
spi_engine->tx_buf = NULL;
}
}
static void spi_engine_rx_next(struct spi_engine *spi_engine)
{
struct spi_transfer *xfer = spi_engine->rx_xfer;
do {
spi_engine_xfer_next(spi_engine, &xfer);
} while (xfer && !xfer->rx_buf);
spi_engine->rx_xfer = xfer;
if (xfer) {
spi_engine->rx_length = xfer->len;
spi_engine->rx_buf = xfer->rx_buf;
} else {
spi_engine->rx_buf = NULL;
}
}
static bool spi_engine_write_cmd_fifo(struct spi_engine *spi_engine)
{
void __iomem *addr = spi_engine->base + SPI_ENGINE_REG_CMD_FIFO;
unsigned int n, m, i;
const uint16_t *buf;
n = readl_relaxed(spi_engine->base + SPI_ENGINE_REG_CMD_FIFO_ROOM);
while (n && spi_engine->cmd_length) {
m = min(n, spi_engine->cmd_length);
buf = spi_engine->cmd_buf;
for (i = 0; i < m; i++)
writel_relaxed(buf[i], addr);
spi_engine->cmd_buf += m;
spi_engine->cmd_length -= m;
n -= m;
}
return spi_engine->cmd_length != 0;
}
static bool spi_engine_write_tx_fifo(struct spi_engine *spi_engine)
{
void __iomem *addr = spi_engine->base + SPI_ENGINE_REG_SDO_DATA_FIFO;
unsigned int n, m, i;
const uint8_t *buf;
n = readl_relaxed(spi_engine->base + SPI_ENGINE_REG_SDO_FIFO_ROOM);
while (n && spi_engine->tx_length) {
m = min(n, spi_engine->tx_length);
buf = spi_engine->tx_buf;
for (i = 0; i < m; i++)
writel_relaxed(buf[i], addr);
spi_engine->tx_buf += m;
spi_engine->tx_length -= m;
n -= m;
if (spi_engine->tx_length == 0)
spi_engine_tx_next(spi_engine);
}
return spi_engine->tx_length != 0;
}
static bool spi_engine_read_rx_fifo(struct spi_engine *spi_engine)
{
void __iomem *addr = spi_engine->base + SPI_ENGINE_REG_SDI_DATA_FIFO;
unsigned int n, m, i;
uint8_t *buf;
n = readl_relaxed(spi_engine->base + SPI_ENGINE_REG_SDI_FIFO_LEVEL);
while (n && spi_engine->rx_length) {
m = min(n, spi_engine->rx_length);
buf = spi_engine->rx_buf;
for (i = 0; i < m; i++)
buf[i] = readl_relaxed(addr);
spi_engine->rx_buf += m;
spi_engine->rx_length -= m;
n -= m;
if (spi_engine->rx_length == 0)
spi_engine_rx_next(spi_engine);
}
return spi_engine->rx_length != 0;
}
static irqreturn_t spi_engine_irq(int irq, void *devid)
{
struct spi_master *master = devid;
struct spi_engine *spi_engine = spi_master_get_devdata(master);
unsigned int disable_int = 0;
unsigned int pending;
pending = readl_relaxed(spi_engine->base + SPI_ENGINE_REG_INT_PENDING);
if (pending & SPI_ENGINE_INT_SYNC) {
writel_relaxed(SPI_ENGINE_INT_SYNC,
spi_engine->base + SPI_ENGINE_REG_INT_PENDING);
spi_engine->completed_id = readl_relaxed(
spi_engine->base + SPI_ENGINE_REG_SYNC_ID);
}
spin_lock(&spi_engine->lock);
if (pending & SPI_ENGINE_INT_CMD_ALMOST_EMPTY) {
if (!spi_engine_write_cmd_fifo(spi_engine))
disable_int |= SPI_ENGINE_INT_CMD_ALMOST_EMPTY;
}
if (pending & SPI_ENGINE_INT_SDO_ALMOST_EMPTY) {
if (!spi_engine_write_tx_fifo(spi_engine))
disable_int |= SPI_ENGINE_INT_SDO_ALMOST_EMPTY;
}
if (pending & (SPI_ENGINE_INT_SDI_ALMOST_FULL | SPI_ENGINE_INT_SYNC)) {
if (!spi_engine_read_rx_fifo(spi_engine))
disable_int |= SPI_ENGINE_INT_SDI_ALMOST_FULL;
}
if (pending & SPI_ENGINE_INT_SYNC) {
if (spi_engine->msg &&
spi_engine->completed_id == spi_engine->sync_id) {
struct spi_message *msg = spi_engine->msg;
kfree(spi_engine->p);
msg->status = 0;
msg->actual_length = msg->frame_length;
spi_engine->msg = NULL;
spi_finalize_current_message(master);
disable_int |= SPI_ENGINE_INT_SYNC;
}
}
if (disable_int) {
spi_engine->int_enable &= ~disable_int;
writel_relaxed(spi_engine->int_enable,
spi_engine->base + SPI_ENGINE_REG_INT_ENABLE);
}
spin_unlock(&spi_engine->lock);
return IRQ_HANDLED;
}
static int spi_engine_transfer_one_message(struct spi_master *master,
struct spi_message *msg)
{
struct spi_engine_program p_dry, *p;
struct spi_engine *spi_engine = spi_master_get_devdata(master);
unsigned int int_enable = 0;
unsigned long flags;
size_t size;
p_dry.length = 0;
spi_engine_compile_message(spi_engine, msg, true, &p_dry);
size = sizeof(*p->instructions) * (p_dry.length + 1);
p = kzalloc(sizeof(*p) + size, GFP_KERNEL);
if (!p)
return -ENOMEM;
spi_engine_compile_message(spi_engine, msg, false, p);
spin_lock_irqsave(&spi_engine->lock, flags);
spi_engine->sync_id = (spi_engine->sync_id + 1) & 0xff;
spi_engine_program_add_cmd(p, false,
SPI_ENGINE_CMD_SYNC(spi_engine->sync_id));
spi_engine->msg = msg;
spi_engine->p = p;
spi_engine->cmd_buf = p->instructions;
spi_engine->cmd_length = p->length;
if (spi_engine_write_cmd_fifo(spi_engine))
int_enable |= SPI_ENGINE_INT_CMD_ALMOST_EMPTY;
spi_engine_tx_next(spi_engine);
if (spi_engine_write_tx_fifo(spi_engine))
int_enable |= SPI_ENGINE_INT_SDO_ALMOST_EMPTY;
spi_engine_rx_next(spi_engine);
if (spi_engine->rx_length != 0)
int_enable |= SPI_ENGINE_INT_SDI_ALMOST_FULL;
int_enable |= SPI_ENGINE_INT_SYNC;
writel_relaxed(int_enable,
spi_engine->base + SPI_ENGINE_REG_INT_ENABLE);
spi_engine->int_enable = int_enable;
spin_unlock_irqrestore(&spi_engine->lock, flags);
return 0;
}
static int spi_engine_probe(struct platform_device *pdev)
{
struct spi_engine *spi_engine;
struct spi_master *master;
unsigned int version;
struct resource *res;
int irq;
int ret;
irq = platform_get_irq(pdev, 0);
if (irq <= 0)
return -ENXIO;
spi_engine = devm_kzalloc(&pdev->dev, sizeof(*spi_engine), GFP_KERNEL);
if (!spi_engine)
return -ENOMEM;
master = spi_alloc_master(&pdev->dev, 0);
if (!master)
return -ENOMEM;
spi_master_set_devdata(master, spi_engine);
spin_lock_init(&spi_engine->lock);
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
spi_engine->base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(spi_engine->base)) {
ret = PTR_ERR(spi_engine->base);
goto err_put_master;
}
version = readl(spi_engine->base + SPI_ENGINE_REG_VERSION);
if (SPI_ENGINE_VERSION_MAJOR(version) != 1) {
dev_err(&pdev->dev, "Unsupported peripheral version %u.%u.%c\n",
SPI_ENGINE_VERSION_MAJOR(version),
SPI_ENGINE_VERSION_MINOR(version),
SPI_ENGINE_VERSION_PATCH(version));
ret = -ENODEV;
goto err_put_master;
}
spi_engine->clk = devm_clk_get(&pdev->dev, "s_axi_aclk");
if (IS_ERR(spi_engine->clk)) {
ret = PTR_ERR(spi_engine->clk);
goto err_put_master;
}
spi_engine->ref_clk = devm_clk_get(&pdev->dev, "spi_clk");
if (IS_ERR(spi_engine->ref_clk)) {
ret = PTR_ERR(spi_engine->ref_clk);
goto err_put_master;
}
ret = clk_prepare_enable(spi_engine->clk);
if (ret)
goto err_put_master;
ret = clk_prepare_enable(spi_engine->ref_clk);
if (ret)
goto err_clk_disable;
writel_relaxed(0x00, spi_engine->base + SPI_ENGINE_REG_RESET);
writel_relaxed(0xff, spi_engine->base + SPI_ENGINE_REG_INT_PENDING);
writel_relaxed(0x00, spi_engine->base + SPI_ENGINE_REG_INT_ENABLE);
ret = request_irq(irq, spi_engine_irq, 0, pdev->name, master);
if (ret)
goto err_ref_clk_disable;
master->dev.of_node = pdev->dev.of_node;
master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_3WIRE;
master->bits_per_word_mask = SPI_BPW_MASK(8);
master->max_speed_hz = clk_get_rate(spi_engine->ref_clk) / 2;
master->transfer_one_message = spi_engine_transfer_one_message;
master->num_chipselect = 8;
ret = spi_register_master(master);
if (ret)
goto err_free_irq;
platform_set_drvdata(pdev, master);
return 0;
err_free_irq:
free_irq(irq, master);
err_ref_clk_disable:
clk_disable_unprepare(spi_engine->ref_clk);
err_clk_disable:
clk_disable_unprepare(spi_engine->clk);
err_put_master:
spi_master_put(master);
return ret;
}
static int spi_engine_remove(struct platform_device *pdev)
{
struct spi_master *master = platform_get_drvdata(pdev);
struct spi_engine *spi_engine = spi_master_get_devdata(master);
int irq = platform_get_irq(pdev, 0);
spi_unregister_master(master);
free_irq(irq, master);
writel_relaxed(0xff, spi_engine->base + SPI_ENGINE_REG_INT_PENDING);
writel_relaxed(0x00, spi_engine->base + SPI_ENGINE_REG_INT_ENABLE);
writel_relaxed(0x01, spi_engine->base + SPI_ENGINE_REG_RESET);
clk_disable_unprepare(spi_engine->ref_clk);
clk_disable_unprepare(spi_engine->clk);
return 0;
}
static const struct of_device_id spi_engine_match_table[] = {
{ .compatible = "adi,axi-spi-engine-1.00.a" },
{ },
};
MODULE_DEVICE_TABLE(of, spi_engine_match_table);
static struct platform_driver spi_engine_driver = {
.probe = spi_engine_probe,
.remove = spi_engine_remove,
.driver = {
.name = "spi-engine",
.of_match_table = spi_engine_match_table,
},
};
module_platform_driver(spi_engine_driver);
MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
MODULE_DESCRIPTION("Analog Devices SPI engine peripheral driver");
MODULE_LICENSE("GPL");