/* SPDX-License-Identifier: BSD-2-Clause */
/*
* Copyright (C) 2021 Jan Sommer, German Aerospace Center (DLR)
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <bsp.h>
#include <rtems/irq-extension.h>
#include <sys/param.h> /* MAX() */
#include <dev/spi/spi.h>
#include <dev/spi/xilinx-axi-spi.h>
#include <dev/spi/xilinx-axi-spi-regs.h>
#define XILINX_AXI_SPI_CS_NONE 0xFF
typedef struct xilinx_axi_spi_bus xilinx_axi_spi_bus;
struct xilinx_axi_spi_bus {
spi_bus base;
volatile xilinx_axi_spi *regs;
uint32_t fifo_size;
uint32_t num_cs;
uint32_t msg_todo;
const spi_ioc_transfer *msg;
uint32_t todo;
uint32_t in_transfer;
uint8_t *rx_buf;
const uint8_t *tx_buf;
rtems_id task_id;
rtems_vector_number irq;
};
static void xilinx_axi_spi_disable_interrupts(volatile xilinx_axi_spi *regs)
{
regs->globalirq = 0;
regs->irqenable = 0;
}
static bool xilinx_axi_spi_rx_fifo_not_empty(volatile xilinx_axi_spi *regs)
{
return (regs->status & XILINX_AXI_SPI_STATUS_RXEMPTY) == 0;
}
static void xilinx_axi_spi_reset(xilinx_axi_spi_bus *bus)
{
volatile xilinx_axi_spi *regs = bus->regs;
uint32_t control;
/* Initiate soft reset for initial state */
regs->reset = XILINX_AXI_SPI_RESET;
/* Configure as master */
control = regs->control;
control |= XILINX_AXI_SPI_CONTROL_MSTREN;
regs->control = control;
}
static void xilinx_axi_spi_done(xilinx_axi_spi_bus *bus)
{
volatile xilinx_axi_spi *regs = bus->regs;
uint32_t control = regs->control;
control &= ~XILINX_AXI_SPI_CONTROL_SPIEN;
regs->control = control;
xilinx_axi_spi_disable_interrupts(regs);
rtems_event_transient_send(bus->task_id);
}
static void xilinx_axi_spi_push(xilinx_axi_spi_bus *bus, volatile xilinx_axi_spi *regs)
{
while (bus->todo > 0 && bus->in_transfer < bus->fifo_size) {
uint8_t val = 0;
if (bus->tx_buf != NULL) {
val = *bus->tx_buf;
++bus->tx_buf;
}
--bus->todo;
regs->txdata = val;
++bus->in_transfer;
}
}
static void
xilinx_axi_spi_set_chipsel(xilinx_axi_spi_bus *bus, uint32_t cs)
{
volatile xilinx_axi_spi *regs = bus->regs;
uint32_t cs_bit = XILINX_AXI_SPI_CS_NONE;
if (cs != SPI_NO_CS && cs < bus->num_cs) {
cs_bit &= ~(1<<cs);
}
bus->base.cs = cs;
regs->cs = cs_bit;
}
static void xilinx_axi_spi_config(
xilinx_axi_spi_bus *bus,
volatile xilinx_axi_spi *regs,
uint32_t mode,
uint8_t cs
)
{
spi_bus *base = &bus->base;
uint32_t control = regs->control;
control &= ~XILINX_AXI_SPI_CONTROL_SPIEN;
regs->control = control;
if ((mode & SPI_CPHA) != 0) {
control |= XILINX_AXI_SPI_CONTROL_CPHA;
} else {
control &= ~XILINX_AXI_SPI_CONTROL_CPHA;
}
if ((mode & SPI_CPOL) != 0) {
control |= XILINX_AXI_SPI_CONTROL_CPOL;
} else {
control &= ~XILINX_AXI_SPI_CONTROL_CPOL;
}
if ((mode & SPI_LOOP) != 0) {
control |= XILINX_AXI_SPI_CONTROL_LOOP;
} else {
control &= ~XILINX_AXI_SPI_CONTROL_LOOP;
}
regs->control = control;
xilinx_axi_spi_set_chipsel(bus, cs);
base->mode = mode;
base->cs = cs;
}
static void
xilinx_axi_spi_next_msg(xilinx_axi_spi_bus *bus, volatile xilinx_axi_spi *regs)
{
uint32_t control = regs->control;
control |= XILINX_AXI_SPI_CONTROL_MST_TRANS_INHIBIT
| XILINX_AXI_SPI_CONTROL_RX_FIFO_RESET
| XILINX_AXI_SPI_CONTROL_TX_FIFO_RESET;
regs->control = control;
if (bus->msg_todo > 0) {
const spi_ioc_transfer *msg;
spi_bus *base = &bus->base;
msg = bus->msg;
if (
msg->mode != base->mode
|| msg->cs != base->cs
) {
xilinx_axi_spi_config(
bus,
regs,
msg->mode,
msg->cs
);
}
if ((msg->mode & SPI_NO_CS) != 0) {
xilinx_axi_spi_set_chipsel(bus, XILINX_AXI_SPI_CS_NONE);
}
bus->todo = msg->len;
bus->rx_buf = msg->rx_buf;
bus->tx_buf = msg->tx_buf;
xilinx_axi_spi_push(bus, regs);
xilinx_axi_spi_disable_interrupts(regs);
if (
bus->todo < bus->fifo_size
|| bus->fifo_size == 1) {
/* if the msg fits into the FIFO, wait for empty TX buffer */
regs->irqenable = XILINX_AXI_SPI_IRQ_TXEMPTY;
} else {
/* if the msg does not fit, refill tx_buf when the tx FIFO is half empty */
regs->irqenable = XILINX_AXI_SPI_IRQ_TXHALF;
}
regs->globalirq = XILINX_AXI_SPI_GLOBAL_IRQ_ENABLE;
control = regs->control;
control |= XILINX_AXI_SPI_CONTROL_SPIEN;
control &= ~XILINX_AXI_SPI_CONTROL_MST_TRANS_INHIBIT;
regs->control = control;
} else {
xilinx_axi_spi_done(bus);
}
}
static void xilinx_axi_spi_interrupt(void *arg)
{
xilinx_axi_spi_bus *bus;
volatile xilinx_axi_spi *regs;
bus = arg;
regs = bus->regs;
/* Clear interrupt flag. It's safe, since only one IRQ active at a time */
regs->irqstatus = regs->irqenable;
while (xilinx_axi_spi_rx_fifo_not_empty(regs)) {
uint32_t val = regs->rxdata;
if (bus->rx_buf != NULL) {
*bus->rx_buf = (uint8_t)val;
++bus->rx_buf;
}
--bus->in_transfer;
}
if (bus->todo > 0) {
xilinx_axi_spi_push(bus, regs);
} else if (bus->in_transfer > 0) {
/* Wait until all bytes have been transfered */
regs->irqenable = XILINX_AXI_SPI_IRQ_TXEMPTY;
} else {
--bus->msg_todo;
++bus->msg;
xilinx_axi_spi_next_msg(bus, regs);
}
}
static int xilinx_axi_spi_check_messages(
xilinx_axi_spi_bus *bus,
const spi_ioc_transfer *msg,
uint32_t size)
{
while(size > 0) {
if (msg->bits_per_word != 8) {
return -EINVAL;
}
if ((msg->mode &
~(SPI_CPHA | SPI_CPOL | SPI_NO_CS)) != 0) {
return -EINVAL;
}
if ((msg->mode & SPI_NO_CS) == 0 &&
(msg->cs > bus->num_cs)) {
return -EINVAL;
}
++msg;
--size;
}
return 0;
}
static int xilinx_axi_spi_transfer(
spi_bus *base,
const spi_ioc_transfer *msgs,
uint32_t n
)
{
xilinx_axi_spi_bus *bus;
int rv;
bus = (xilinx_axi_spi_bus *) base;
rv = xilinx_axi_spi_check_messages(bus, msgs, n);
if (rv == 0) {
bus->msg_todo = n;
bus->msg = &msgs[0];
bus->task_id = rtems_task_self();
xilinx_axi_spi_next_msg(bus, bus->regs);
rtems_event_transient_receive(RTEMS_WAIT, RTEMS_NO_TIMEOUT);
xilinx_axi_spi_set_chipsel(bus, XILINX_AXI_SPI_CS_NONE);
}
return rv;
}
static void xilinx_axi_spi_destroy(spi_bus *base)
{
xilinx_axi_spi_bus *bus;
bus = (xilinx_axi_spi_bus *) base;
rtems_interrupt_handler_remove(bus->irq, xilinx_axi_spi_interrupt, bus);
spi_bus_destroy_and_free(&bus->base);
}
static int xilinx_axi_spi_setup(spi_bus *base)
{
xilinx_axi_spi_bus *bus;
uint32_t mode = base->mode;
bus = (xilinx_axi_spi_bus *) base;
if (bus->base.bits_per_word > 8) {
return -EINVAL;
}
/* SPI_CS_HIGH not supported */
if (mode & SPI_CS_HIGH) {
return -EINVAL;
}
xilinx_axi_spi_config(
bus,
bus->regs,
base->mode,
base->cs
);
return 0;
}
int spi_bus_register_xilinx_axi(
const char *bus_path,
uintptr_t register_base,
uint32_t fifo_size,
uint32_t num_cs,
rtems_vector_number irq)
{
xilinx_axi_spi_bus *bus;
spi_bus *base;
int sc;
if (fifo_size != 0 && fifo_size != 16 && fifo_size != 256) {
return -1;
}
if (num_cs > 32) {
return -1;
}
bus = (xilinx_axi_spi_bus *) spi_bus_alloc_and_init(sizeof(*bus));
if (bus == NULL){
return -1;
}
base = &bus->base;
bus->regs = (volatile xilinx_axi_spi *) register_base;
bus->irq = irq;
bus->num_cs = num_cs;
/* For operation without FIFO set fifo_size to 1
* so that comparison operators work
*/
if (fifo_size == 0) {
bus->fifo_size = 1;
} else {
bus->fifo_size = fifo_size;
}
base->cs = SPI_NO_CS;
xilinx_axi_spi_reset(bus);
xilinx_axi_spi_config(
bus,
bus->regs,
base->mode,
base->cs
);
sc = rtems_interrupt_handler_install(
bus->irq,
"XSPI",
RTEMS_INTERRUPT_UNIQUE,
xilinx_axi_spi_interrupt,
bus
);
if (sc != RTEMS_SUCCESSFUL) {
(*bus->base.destroy)(&bus->base);
rtems_set_errno_and_return_minus_one(EAGAIN);
}
bus->base.transfer = xilinx_axi_spi_transfer;
bus->base.destroy = xilinx_axi_spi_destroy;
bus->base.setup = xilinx_axi_spi_setup;
return spi_bus_register(&bus->base, bus_path);
}