blob: e358ac5b4509777e0827630e2f6e58c385f9a54c [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-only
/*
* SPI-Engine SPI controller driver
* Copyright 2015 Analog Devices Inc.
* Author: Lars-Peter Clausen <lars@metafoo.de>
*/
#include <linux/clk.h>
#include <linux/completion.h>
#include <linux/fpga/adi-axi-common.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/module.h>
#include <linux/overflow.h>
#include <linux/platform_device.h>
#include <linux/spi/spi.h>
#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_CMD_REG_XFER_BITS 0x2
#define SPI_ENGINE_MISC_SYNC 0x0
#define SPI_ENGINE_MISC_SLEEP 0x1
#define SPI_ENGINE_TRANSFER_WRITE 0x1
#define SPI_ENGINE_TRANSFER_READ 0x2
/* Arbitrary sync ID for use by host->cur_msg */
#define AXI_SPI_ENGINE_CUR_MSG_SYNC_ID 0x1
#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[] __counted_by(length);
};
/**
* struct spi_engine_message_state - SPI engine per-message state
*/
struct spi_engine_message_state {
/** @cmd_length: Number of elements in cmd_buf array. */
unsigned cmd_length;
/** @cmd_buf: Array of commands not yet written to CMD FIFO. */
const uint16_t *cmd_buf;
/** @tx_xfer: Next xfer with tx_buf not yet fully written to TX FIFO. */
struct spi_transfer *tx_xfer;
/** @tx_length: Size of tx_buf in bytes. */
unsigned int tx_length;
/** @tx_buf: Bytes not yet written to TX FIFO. */
const uint8_t *tx_buf;
/** @rx_xfer: Next xfer with rx_buf not yet fully written to RX FIFO. */
struct spi_transfer *rx_xfer;
/** @rx_length: Size of tx_buf in bytes. */
unsigned int rx_length;
/** @rx_buf: Bytes not yet written to the RX FIFO. */
uint8_t *rx_buf;
};
struct spi_engine {
struct clk *clk;
struct clk *ref_clk;
spinlock_t lock;
void __iomem *base;
struct spi_engine_message_state msg_state;
struct completion msg_complete;
unsigned int int_enable;
};
static void spi_engine_program_add_cmd(struct spi_engine_program *p,
bool dry, uint16_t cmd)
{
p->length++;
if (!dry)
p->instructions[p->length - 1] = cmd;
}
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 void spi_engine_gen_xfer(struct spi_engine_program *p, bool dry,
struct spi_transfer *xfer)
{
unsigned int len;
if (xfer->bits_per_word <= 8)
len = xfer->len;
else if (xfer->bits_per_word <= 16)
len = xfer->len / 2;
else
len = xfer->len / 4;
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,
int delay_ns, u32 sclk_hz)
{
unsigned int t;
/* negative delay indicates error, e.g. from spi_delay_to_ns() */
if (delay_ns <= 0)
return;
/* rounding down since executing the instruction adds a couple of ticks delay */
t = DIV_ROUND_DOWN_ULL((u64)delay_ns * sclk_hz, NSEC_PER_SEC);
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_get_chipselect(spi, 0));
spi_engine_program_add_cmd(p, dry, SPI_ENGINE_CMD_ASSERT(0, mask));
}
/*
* Performs precompile steps on the message.
*
* The SPI core does most of the message/transfer validation and filling in
* fields for us via __spi_validate(). This fixes up anything remaining not
* done there.
*
* NB: This is separate from spi_engine_compile_message() because the latter
* is called twice and would otherwise result in double-evaluation.
*/
static void spi_engine_precompile_message(struct spi_message *msg)
{
unsigned int clk_div, max_hz = msg->spi->controller->max_speed_hz;
struct spi_transfer *xfer;
list_for_each_entry(xfer, &msg->transfers, transfer_list) {
clk_div = DIV_ROUND_UP(max_hz, xfer->speed_hz);
xfer->effective_speed_hz = max_hz / min(clk_div, 256U);
}
}
static void spi_engine_compile_message(struct spi_message *msg, bool dry,
struct spi_engine_program *p)
{
struct spi_device *spi = msg->spi;
struct spi_controller *host = spi->controller;
struct spi_transfer *xfer;
int clk_div, new_clk_div;
bool keep_cs = false;
u8 bits_per_word = 0;
clk_div = 1;
spi_engine_program_add_cmd(p, dry,
SPI_ENGINE_CMD_WRITE(SPI_ENGINE_CMD_REG_CONFIG,
spi_engine_get_config(spi)));
xfer = list_first_entry(&msg->transfers, struct spi_transfer, transfer_list);
spi_engine_gen_cs(p, dry, spi, !xfer->cs_off);
list_for_each_entry(xfer, &msg->transfers, transfer_list) {
new_clk_div = host->max_speed_hz / xfer->effective_speed_hz;
if (new_clk_div != clk_div) {
clk_div = new_clk_div;
/* actual divider used is register value + 1 */
spi_engine_program_add_cmd(p, dry,
SPI_ENGINE_CMD_WRITE(SPI_ENGINE_CMD_REG_CLK_DIV,
clk_div - 1));
}
if (bits_per_word != xfer->bits_per_word) {
bits_per_word = xfer->bits_per_word;
spi_engine_program_add_cmd(p, dry,
SPI_ENGINE_CMD_WRITE(SPI_ENGINE_CMD_REG_XFER_BITS,
bits_per_word));
}
spi_engine_gen_xfer(p, dry, xfer);
spi_engine_gen_sleep(p, dry, spi_delay_to_ns(&xfer->delay, xfer),
xfer->effective_speed_hz);
if (xfer->cs_change) {
if (list_is_last(&xfer->transfer_list, &msg->transfers)) {
keep_cs = true;
} else {
if (!xfer->cs_off)
spi_engine_gen_cs(p, dry, spi, false);
spi_engine_gen_sleep(p, dry, spi_delay_to_ns(
&xfer->cs_change_delay, xfer),
xfer->effective_speed_hz);
if (!list_next_entry(xfer, transfer_list)->cs_off)
spi_engine_gen_cs(p, dry, spi, true);
}
} else if (!list_is_last(&xfer->transfer_list, &msg->transfers) &&
xfer->cs_off != list_next_entry(xfer, transfer_list)->cs_off) {
spi_engine_gen_cs(p, dry, spi, xfer->cs_off);
}
}
if (!keep_cs)
spi_engine_gen_cs(p, dry, spi, false);
/*
* Restore clockdiv to default so that future gen_sleep commands don't
* have to be aware of the current register state.
*/
if (clk_div != 1)
spi_engine_program_add_cmd(p, dry,
SPI_ENGINE_CMD_WRITE(SPI_ENGINE_CMD_REG_CLK_DIV, 0));
}
static void spi_engine_xfer_next(struct spi_message *msg,
struct spi_transfer **_xfer)
{
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_message *msg)
{
struct spi_engine_message_state *st = msg->state;
struct spi_transfer *xfer = st->tx_xfer;
do {
spi_engine_xfer_next(msg, &xfer);
} while (xfer && !xfer->tx_buf);
st->tx_xfer = xfer;
if (xfer) {
st->tx_length = xfer->len;
st->tx_buf = xfer->tx_buf;
} else {
st->tx_buf = NULL;
}
}
static void spi_engine_rx_next(struct spi_message *msg)
{
struct spi_engine_message_state *st = msg->state;
struct spi_transfer *xfer = st->rx_xfer;
do {
spi_engine_xfer_next(msg, &xfer);
} while (xfer && !xfer->rx_buf);
st->rx_xfer = xfer;
if (xfer) {
st->rx_length = xfer->len;
st->rx_buf = xfer->rx_buf;
} else {
st->rx_buf = NULL;
}
}
static bool spi_engine_write_cmd_fifo(struct spi_engine *spi_engine,
struct spi_message *msg)
{
void __iomem *addr = spi_engine->base + SPI_ENGINE_REG_CMD_FIFO;
struct spi_engine_message_state *st = msg->state;
unsigned int n, m, i;
const uint16_t *buf;
n = readl_relaxed(spi_engine->base + SPI_ENGINE_REG_CMD_FIFO_ROOM);
while (n && st->cmd_length) {
m = min(n, st->cmd_length);
buf = st->cmd_buf;
for (i = 0; i < m; i++)
writel_relaxed(buf[i], addr);
st->cmd_buf += m;
st->cmd_length -= m;
n -= m;
}
return st->cmd_length != 0;
}
static bool spi_engine_write_tx_fifo(struct spi_engine *spi_engine,
struct spi_message *msg)
{
void __iomem *addr = spi_engine->base + SPI_ENGINE_REG_SDO_DATA_FIFO;
struct spi_engine_message_state *st = msg->state;
unsigned int n, m, i;
n = readl_relaxed(spi_engine->base + SPI_ENGINE_REG_SDO_FIFO_ROOM);
while (n && st->tx_length) {
if (st->tx_xfer->bits_per_word <= 8) {
const u8 *buf = st->tx_buf;
m = min(n, st->tx_length);
for (i = 0; i < m; i++)
writel_relaxed(buf[i], addr);
st->tx_buf += m;
st->tx_length -= m;
} else if (st->tx_xfer->bits_per_word <= 16) {
const u16 *buf = (const u16 *)st->tx_buf;
m = min(n, st->tx_length / 2);
for (i = 0; i < m; i++)
writel_relaxed(buf[i], addr);
st->tx_buf += m * 2;
st->tx_length -= m * 2;
} else {
const u32 *buf = (const u32 *)st->tx_buf;
m = min(n, st->tx_length / 4);
for (i = 0; i < m; i++)
writel_relaxed(buf[i], addr);
st->tx_buf += m * 4;
st->tx_length -= m * 4;
}
n -= m;
if (st->tx_length == 0)
spi_engine_tx_next(msg);
}
return st->tx_length != 0;
}
static bool spi_engine_read_rx_fifo(struct spi_engine *spi_engine,
struct spi_message *msg)
{
void __iomem *addr = spi_engine->base + SPI_ENGINE_REG_SDI_DATA_FIFO;
struct spi_engine_message_state *st = msg->state;
unsigned int n, m, i;
n = readl_relaxed(spi_engine->base + SPI_ENGINE_REG_SDI_FIFO_LEVEL);
while (n && st->rx_length) {
if (st->rx_xfer->bits_per_word <= 8) {
u8 *buf = st->rx_buf;
m = min(n, st->rx_length);
for (i = 0; i < m; i++)
buf[i] = readl_relaxed(addr);
st->rx_buf += m;
st->rx_length -= m;
} else if (st->rx_xfer->bits_per_word <= 16) {
u16 *buf = (u16 *)st->rx_buf;
m = min(n, st->rx_length / 2);
for (i = 0; i < m; i++)
buf[i] = readl_relaxed(addr);
st->rx_buf += m * 2;
st->rx_length -= m * 2;
} else {
u32 *buf = (u32 *)st->rx_buf;
m = min(n, st->rx_length / 4);
for (i = 0; i < m; i++)
buf[i] = readl_relaxed(addr);
st->rx_buf += m * 4;
st->rx_length -= m * 4;
}
n -= m;
if (st->rx_length == 0)
spi_engine_rx_next(msg);
}
return st->rx_length != 0;
}
static irqreturn_t spi_engine_irq(int irq, void *devid)
{
struct spi_controller *host = devid;
struct spi_message *msg = host->cur_msg;
struct spi_engine *spi_engine = spi_controller_get_devdata(host);
unsigned int disable_int = 0;
unsigned int pending;
int completed_id = -1;
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);
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, msg))
disable_int |= SPI_ENGINE_INT_CMD_ALMOST_EMPTY;
}
if (pending & SPI_ENGINE_INT_SDO_ALMOST_EMPTY) {
if (!spi_engine_write_tx_fifo(spi_engine, msg))
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, msg))
disable_int |= SPI_ENGINE_INT_SDI_ALMOST_FULL;
}
if (pending & SPI_ENGINE_INT_SYNC && msg) {
if (completed_id == AXI_SPI_ENGINE_CUR_MSG_SYNC_ID) {
msg->status = 0;
msg->actual_length = msg->frame_length;
complete(&spi_engine->msg_complete);
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_optimize_message(struct spi_message *msg)
{
struct spi_engine_program p_dry, *p;
spi_engine_precompile_message(msg);
p_dry.length = 0;
spi_engine_compile_message(msg, true, &p_dry);
p = kzalloc(struct_size(p, instructions, p_dry.length + 1), GFP_KERNEL);
if (!p)
return -ENOMEM;
spi_engine_compile_message(msg, false, p);
spi_engine_program_add_cmd(p, false, SPI_ENGINE_CMD_SYNC(
AXI_SPI_ENGINE_CUR_MSG_SYNC_ID));
msg->opt_state = p;
return 0;
}
static int spi_engine_unoptimize_message(struct spi_message *msg)
{
kfree(msg->opt_state);
return 0;
}
static int spi_engine_transfer_one_message(struct spi_controller *host,
struct spi_message *msg)
{
struct spi_engine *spi_engine = spi_controller_get_devdata(host);
struct spi_engine_message_state *st = &spi_engine->msg_state;
struct spi_engine_program *p = msg->opt_state;
unsigned int int_enable = 0;
unsigned long flags;
/* reinitialize message state for this transfer */
memset(st, 0, sizeof(*st));
st->cmd_buf = p->instructions;
st->cmd_length = p->length;
msg->state = st;
reinit_completion(&spi_engine->msg_complete);
spin_lock_irqsave(&spi_engine->lock, flags);
if (spi_engine_write_cmd_fifo(spi_engine, msg))
int_enable |= SPI_ENGINE_INT_CMD_ALMOST_EMPTY;
spi_engine_tx_next(msg);
if (spi_engine_write_tx_fifo(spi_engine, msg))
int_enable |= SPI_ENGINE_INT_SDO_ALMOST_EMPTY;
spi_engine_rx_next(msg);
if (st->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);
if (!wait_for_completion_timeout(&spi_engine->msg_complete,
msecs_to_jiffies(5000))) {
dev_err(&host->dev,
"Timeout occurred while waiting for transfer to complete. Hardware is probably broken.\n");
msg->status = -ETIMEDOUT;
}
spi_finalize_current_message(host);
return msg->status;
}
static void spi_engine_release_hw(void *p)
{
struct spi_engine *spi_engine = p;
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);
}
static int spi_engine_probe(struct platform_device *pdev)
{
struct spi_engine *spi_engine;
struct spi_controller *host;
unsigned int version;
int irq;
int ret;
irq = platform_get_irq(pdev, 0);
if (irq < 0)
return irq;
host = devm_spi_alloc_host(&pdev->dev, sizeof(*spi_engine));
if (!host)
return -ENOMEM;
spi_engine = spi_controller_get_devdata(host);
spin_lock_init(&spi_engine->lock);
init_completion(&spi_engine->msg_complete);
spi_engine->clk = devm_clk_get_enabled(&pdev->dev, "s_axi_aclk");
if (IS_ERR(spi_engine->clk))
return PTR_ERR(spi_engine->clk);
spi_engine->ref_clk = devm_clk_get_enabled(&pdev->dev, "spi_clk");
if (IS_ERR(spi_engine->ref_clk))
return PTR_ERR(spi_engine->ref_clk);
spi_engine->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(spi_engine->base))
return PTR_ERR(spi_engine->base);
version = readl(spi_engine->base + ADI_AXI_REG_VERSION);
if (ADI_AXI_PCORE_VER_MAJOR(version) != 1) {
dev_err(&pdev->dev, "Unsupported peripheral version %u.%u.%u\n",
ADI_AXI_PCORE_VER_MAJOR(version),
ADI_AXI_PCORE_VER_MINOR(version),
ADI_AXI_PCORE_VER_PATCH(version));
return -ENODEV;
}
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 = devm_add_action_or_reset(&pdev->dev, spi_engine_release_hw,
spi_engine);
if (ret)
return ret;
ret = devm_request_irq(&pdev->dev, irq, spi_engine_irq, 0, pdev->name,
host);
if (ret)
return ret;
host->dev.of_node = pdev->dev.of_node;
host->mode_bits = SPI_CPOL | SPI_CPHA | SPI_3WIRE;
host->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 32);
host->max_speed_hz = clk_get_rate(spi_engine->ref_clk) / 2;
host->transfer_one_message = spi_engine_transfer_one_message;
host->optimize_message = spi_engine_optimize_message;
host->unoptimize_message = spi_engine_unoptimize_message;
host->num_chipselect = 8;
if (host->max_speed_hz == 0)
return dev_err_probe(&pdev->dev, -EINVAL, "spi_clk rate is 0");
ret = devm_spi_register_controller(&pdev->dev, host);
if (ret)
return ret;
platform_set_drvdata(pdev, host);
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,
.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");