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/*
* Copyright (c) 2018 - 2019 Antmicro <www.antmicro.com>
*
* SPDX-License-Identifier: Apache-2.0
*/
#define DT_DRV_COMPAT litex_uart0
#include <zephyr/kernel.h>
#include <zephyr/arch/cpu.h>
#include <zephyr/init.h>
#include <zephyr/irq.h>
#include <zephyr/device.h>
#include <zephyr/drivers/uart.h>
#include <zephyr/types.h>
#include <soc.h>
#define UART_RXTX_ADDR DT_INST_REG_ADDR_BY_NAME(0, rxtx)
#define UART_TXFULL_ADDR DT_INST_REG_ADDR_BY_NAME(0, txfull)
#define UART_RXEMPTY_ADDR DT_INST_REG_ADDR_BY_NAME(0, rxempty)
#define UART_EV_STATUS_ADDR DT_INST_REG_ADDR_BY_NAME(0, ev_status)
#define UART_EV_PENDING_ADDR DT_INST_REG_ADDR_BY_NAME(0, ev_pending)
#define UART_EV_ENABLE_ADDR DT_INST_REG_ADDR_BY_NAME(0, ev_enable)
#define UART_TXEMPTY_ADDR DT_INST_REG_ADDR_BY_NAME(0, txempty)
#define UART_RXFULL_ADDR DT_INST_REG_ADDR_BY_NAME(0, rxfull)
#define UART_EV_TX (1 << 0)
#define UART_EV_RX (1 << 1)
#define UART_IRQ DT_INST_IRQN(0)
#ifdef CONFIG_UART_INTERRUPT_DRIVEN
typedef void (*irq_cfg_func_t)(void);
#endif
struct uart_liteuart_device_config {
uint32_t port;
uint32_t sys_clk_freq;
uint32_t baud_rate;
#ifdef CONFIG_UART_INTERRUPT_DRIVEN
irq_cfg_func_t cfg_func;
#endif
};
struct uart_liteuart_data {
#ifdef CONFIG_UART_INTERRUPT_DRIVEN
uart_irq_callback_user_data_t callback;
void *cb_data;
#endif
};
/**
* @brief Output a character in polled mode.
*
* Writes data to tx register. Waits for space if transmitter is full.
*
* @param dev UART device struct
* @param c Character to send
*/
static void uart_liteuart_poll_out(const struct device *dev, unsigned char c)
{
/* wait for space */
while (litex_read8(UART_TXFULL_ADDR)) {
}
litex_write8(c, UART_RXTX_ADDR);
}
/**
* @brief Poll the device for input.
*
* @param dev UART device struct
* @param c Pointer to character
*
* @return 0 if a character arrived, -1 if the input buffer if empty.
*/
static int uart_liteuart_poll_in(const struct device *dev, unsigned char *c)
{
if (!litex_read8(UART_RXEMPTY_ADDR)) {
*c = litex_read8(UART_RXTX_ADDR);
/* refresh UART_RXEMPTY by writing UART_EV_RX
* to UART_EV_PENDING
*/
litex_write8(UART_EV_RX, UART_EV_PENDING_ADDR);
return 0;
} else {
return -1;
}
}
#ifdef CONFIG_UART_INTERRUPT_DRIVEN
/**
* @brief Enable TX interrupt in event register
*
* @param dev UART device struct
*/
static void uart_liteuart_irq_tx_enable(const struct device *dev)
{
uint8_t enable = litex_read8(UART_EV_ENABLE_ADDR);
litex_write8(enable | UART_EV_TX, UART_EV_ENABLE_ADDR);
}
/**
* @brief Disable TX interrupt in event register
*
* @param dev UART device struct
*/
static void uart_liteuart_irq_tx_disable(const struct device *dev)
{
uint8_t enable = litex_read8(UART_EV_ENABLE_ADDR);
litex_write8(enable & ~(UART_EV_TX), UART_EV_ENABLE_ADDR);
}
/**
* @brief Enable RX interrupt in event register
*
* @param dev UART device struct
*/
static void uart_liteuart_irq_rx_enable(const struct device *dev)
{
uint8_t enable = litex_read8(UART_EV_ENABLE_ADDR);
litex_write8(enable | UART_EV_RX, UART_EV_ENABLE_ADDR);
}
/**
* @brief Disable RX interrupt in event register
*
* @param dev UART device struct
*/
static void uart_liteuart_irq_rx_disable(const struct device *dev)
{
uint8_t enable = litex_read8(UART_EV_ENABLE_ADDR);
litex_write8(enable & ~(UART_EV_RX), UART_EV_ENABLE_ADDR);
}
/**
* @brief Check if Tx IRQ has been raised and UART is ready to accept new data
*
* @param dev UART device struct
*
* @return 1 if an IRQ has been raised, 0 otherwise
*/
static int uart_liteuart_irq_tx_ready(const struct device *dev)
{
uint8_t val = litex_read8(UART_TXFULL_ADDR);
return !val;
}
/**
* @brief Check if Rx IRQ has been raised and there's data to be read from UART
*
* @param dev UART device struct
*
* @return 1 if an IRQ has been raised, 0 otherwise
*/
static int uart_liteuart_irq_rx_ready(const struct device *dev)
{
uint8_t pending;
pending = litex_read8(UART_EV_PENDING_ADDR);
if (pending & UART_EV_RX) {
return 1;
} else {
return 0;
}
}
/**
* @brief Fill FIFO with data
*
* @param dev UART device struct
* @param tx_data Data to transmit
* @param size Number of bytes to send
*
* @return Number of bytes sent
*/
static int uart_liteuart_fifo_fill(const struct device *dev,
const uint8_t *tx_data, int size)
{
int i;
for (i = 0; i < size && !litex_read8(UART_TXFULL_ADDR); i++) {
litex_write8(tx_data[i], UART_RXTX_ADDR);
}
return i;
}
/**
* @brief Read data from FIFO
*
* @param dev UART device struct
* @param rxData Data container
* @param size Container size
*
* @return Number of bytes read
*/
static int uart_liteuart_fifo_read(const struct device *dev,
uint8_t *rx_data, const int size)
{
int i;
for (i = 0; i < size && !litex_read8(UART_RXEMPTY_ADDR); i++) {
rx_data[i] = litex_read8(UART_RXTX_ADDR);
/* refresh UART_RXEMPTY by writing UART_EV_RX
* to UART_EV_PENDING
*/
litex_write8(UART_EV_RX, UART_EV_PENDING_ADDR);
}
return i;
}
static void uart_liteuart_irq_err(const struct device *dev)
{
ARG_UNUSED(dev);
}
/**
* @brief Check if any IRQ is pending
*
* @param dev UART device struct
*
* @return 1 if an IRQ is pending, 0 otherwise
*/
static int uart_liteuart_irq_is_pending(const struct device *dev)
{
uint8_t pending;
pending = litex_read8(UART_EV_PENDING_ADDR);
if (pending & (UART_EV_TX | UART_EV_RX)) {
return 1;
} else {
return 0;
}
}
static int uart_liteuart_irq_update(const struct device *dev)
{
return 1;
}
/**
* @brief Set the callback function pointer for IRQ.
*
* @param dev UART device struct
* @param cb Callback function pointer.
*/
static void uart_liteuart_irq_callback_set(const struct device *dev,
uart_irq_callback_user_data_t cb,
void *cb_data)
{
struct uart_liteuart_data *data;
data = dev->data;
data->callback = cb;
data->cb_data = cb_data;
}
static void liteuart_uart_irq_handler(const struct device *dev)
{
struct uart_liteuart_data *data = dev->data;
unsigned int key = irq_lock();
if (data->callback) {
data->callback(dev, data->cb_data);
}
/* Clear RX events, TX events still needed to enqueue the next transfer */
litex_write8(UART_EV_RX, UART_EV_PENDING_ADDR);
irq_unlock(key);
}
#endif /* CONFIG_UART_INTERRUPT_DRIVEN */
static const struct uart_driver_api uart_liteuart_driver_api = {
.poll_in = uart_liteuart_poll_in,
.poll_out = uart_liteuart_poll_out,
.err_check = NULL,
#ifdef CONFIG_UART_INTERRUPT_DRIVEN
.fifo_fill = uart_liteuart_fifo_fill,
.fifo_read = uart_liteuart_fifo_read,
.irq_tx_enable = uart_liteuart_irq_tx_enable,
.irq_tx_disable = uart_liteuart_irq_tx_disable,
.irq_tx_ready = uart_liteuart_irq_tx_ready,
.irq_rx_enable = uart_liteuart_irq_rx_enable,
.irq_rx_disable = uart_liteuart_irq_rx_disable,
.irq_rx_ready = uart_liteuart_irq_rx_ready,
.irq_err_enable = uart_liteuart_irq_err,
.irq_err_disable = uart_liteuart_irq_err,
.irq_is_pending = uart_liteuart_irq_is_pending,
.irq_update = uart_liteuart_irq_update,
.irq_callback_set = uart_liteuart_irq_callback_set
#endif
};
static struct uart_liteuart_data uart_liteuart_data_0;
static int uart_liteuart_init(const struct device *dev);
static const struct uart_liteuart_device_config uart_liteuart_dev_cfg_0 = {
.port = UART_RXTX_ADDR,
.baud_rate = DT_INST_PROP(0, current_speed)
};
DEVICE_DT_INST_DEFINE(0,
uart_liteuart_init,
NULL,
&uart_liteuart_data_0, &uart_liteuart_dev_cfg_0,
PRE_KERNEL_1, CONFIG_SERIAL_INIT_PRIORITY,
(void *)&uart_liteuart_driver_api);
static int uart_liteuart_init(const struct device *dev)
{
litex_write8(UART_EV_TX | UART_EV_RX, UART_EV_PENDING_ADDR);
#ifdef CONFIG_UART_INTERRUPT_DRIVEN
IRQ_CONNECT(UART_IRQ, DT_INST_IRQ(0, priority),
liteuart_uart_irq_handler, DEVICE_DT_INST_GET(0),
0);
irq_enable(UART_IRQ);
#endif
return 0;
}