blob: f7f20d551c72c0831644074a8ce4db891f51adc5 [file] [log] [blame]
/*
* Copyright (c) 2017 Jean-Paul Etienne <fractalclone@gmail.com>
*
* SPDX-License-Identifier: Apache-2.0
*/
/**
* @brief UART driver for the SiFive Freedom Processor
*/
#define DT_DRV_COMPAT sifive_uart0
#include <kernel.h>
#include <arch/cpu.h>
#include <drivers/uart.h>
#define RXDATA_EMPTY (1 << 31) /* Receive FIFO Empty */
#define RXDATA_MASK 0xFF /* Receive Data Mask */
#define TXDATA_FULL (1 << 31) /* Transmit FIFO Full */
#define TXCTRL_TXEN (1 << 0) /* Activate Tx Channel */
#define RXCTRL_RXEN (1 << 0) /* Activate Rx Channel */
#define IE_TXWM (1 << 0) /* TX Interrupt Enable/Pending */
#define IE_RXWM (1 << 1) /* RX Interrupt Enable/Pending */
/*
* RX/TX Threshold count to generate TX/RX Interrupts.
* Used by txctrl and rxctrl registers
*/
#define CTRL_CNT(x) (((x) & 0x07) << 16)
struct uart_sifive_regs_t {
uint32_t tx;
uint32_t rx;
uint32_t txctrl;
uint32_t rxctrl;
uint32_t ie;
uint32_t ip;
uint32_t div;
};
#ifdef CONFIG_UART_INTERRUPT_DRIVEN
typedef void (*irq_cfg_func_t)(void);
#endif
struct uart_sifive_device_config {
uintptr_t port;
uint32_t sys_clk_freq;
uint32_t baud_rate;
uint32_t rxcnt_irq;
uint32_t txcnt_irq;
#ifdef CONFIG_UART_INTERRUPT_DRIVEN
irq_cfg_func_t cfg_func;
#endif
};
struct uart_sifive_data {
#ifdef CONFIG_UART_INTERRUPT_DRIVEN
uart_irq_callback_user_data_t callback;
void *cb_data;
#endif
};
#define DEV_CFG(dev) \
((const struct uart_sifive_device_config * const) \
(dev)->config)
#define DEV_UART(dev) \
((struct uart_sifive_regs_t *)(DEV_CFG(dev))->port)
#define DEV_DATA(dev) \
((struct uart_sifive_data * const)(dev)->data)
/**
* @brief Output a character in polled mode.
*
* Writes data to tx register if transmitter is not full.
*
* @param dev UART device struct
* @param c Character to send
*/
static void uart_sifive_poll_out(const struct device *dev,
unsigned char c)
{
volatile struct uart_sifive_regs_t *uart = DEV_UART(dev);
/* Wait while TX FIFO is full */
while (uart->tx & TXDATA_FULL) {
}
uart->tx = (int)c;
}
/**
* @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_sifive_poll_in(const struct device *dev, unsigned char *c)
{
volatile struct uart_sifive_regs_t *uart = DEV_UART(dev);
uint32_t val = uart->rx;
if (val & RXDATA_EMPTY) {
return -1;
}
*c = (unsigned char)(val & RXDATA_MASK);
return 0;
}
#ifdef CONFIG_UART_INTERRUPT_DRIVEN
/**
* @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_sifive_fifo_fill(const struct device *dev,
const uint8_t *tx_data,
int size)
{
volatile struct uart_sifive_regs_t *uart = DEV_UART(dev);
int i;
for (i = 0; i < size && !(uart->tx & TXDATA_FULL); i++)
uart->tx = (int)tx_data[i];
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_sifive_fifo_read(const struct device *dev,
uint8_t *rx_data,
const int size)
{
volatile struct uart_sifive_regs_t *uart = DEV_UART(dev);
int i;
uint32_t val;
for (i = 0; i < size; i++) {
val = uart->rx;
if (val & RXDATA_EMPTY)
break;
rx_data[i] = (uint8_t)(val & RXDATA_MASK);
}
return i;
}
/**
* @brief Enable TX interrupt in ie register
*
* @param dev UART device struct
*
* @return N/A
*/
static void uart_sifive_irq_tx_enable(const struct device *dev)
{
volatile struct uart_sifive_regs_t *uart = DEV_UART(dev);
uart->ie |= IE_TXWM;
}
/**
* @brief Disable TX interrupt in ie register
*
* @param dev UART device struct
*
* @return N/A
*/
static void uart_sifive_irq_tx_disable(const struct device *dev)
{
volatile struct uart_sifive_regs_t *uart = DEV_UART(dev);
uart->ie &= ~IE_TXWM;
}
/**
* @brief Check if Tx IRQ has been raised
*
* @param dev UART device struct
*
* @return 1 if an IRQ is ready, 0 otherwise
*/
static int uart_sifive_irq_tx_ready(const struct device *dev)
{
volatile struct uart_sifive_regs_t *uart = DEV_UART(dev);
return !!(uart->ip & IE_TXWM);
}
/**
* @brief Check if nothing remains to be transmitted
*
* @param dev UART device struct
*
* @return 1 if nothing remains to be transmitted, 0 otherwise
*/
static int uart_sifive_irq_tx_complete(const struct device *dev)
{
volatile struct uart_sifive_regs_t *uart = DEV_UART(dev);
/*
* No TX EMPTY flag for this controller,
* just check if TX FIFO is not full
*/
return !(uart->tx & TXDATA_FULL);
}
/**
* @brief Enable RX interrupt in ie register
*
* @param dev UART device struct
*
* @return N/A
*/
static void uart_sifive_irq_rx_enable(const struct device *dev)
{
volatile struct uart_sifive_regs_t *uart = DEV_UART(dev);
uart->ie |= IE_RXWM;
}
/**
* @brief Disable RX interrupt in ie register
*
* @param dev UART device struct
*
* @return N/A
*/
static void uart_sifive_irq_rx_disable(const struct device *dev)
{
volatile struct uart_sifive_regs_t *uart = DEV_UART(dev);
uart->ie &= ~IE_RXWM;
}
/**
* @brief Check if Rx IRQ has been raised
*
* @param dev UART device struct
*
* @return 1 if an IRQ is ready, 0 otherwise
*/
static int uart_sifive_irq_rx_ready(const struct device *dev)
{
volatile struct uart_sifive_regs_t *uart = DEV_UART(dev);
return !!(uart->ip & IE_RXWM);
}
/* No error interrupt for this controller */
static void uart_sifive_irq_err_enable(const struct device *dev)
{
ARG_UNUSED(dev);
}
static void uart_sifive_irq_err_disable(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_sifive_irq_is_pending(const struct device *dev)
{
volatile struct uart_sifive_regs_t *uart = DEV_UART(dev);
return !!(uart->ip & (IE_RXWM | IE_TXWM));
}
static int uart_sifive_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.
*
* @return N/A
*/
static void uart_sifive_irq_callback_set(const struct device *dev,
uart_irq_callback_user_data_t cb,
void *cb_data)
{
struct uart_sifive_data *data = DEV_DATA(dev);
data->callback = cb;
data->cb_data = cb_data;
}
static void uart_sifive_irq_handler(const struct device *dev)
{
struct uart_sifive_data *data = DEV_DATA(dev);
if (data->callback)
data->callback(dev, data->cb_data);
}
#endif /* CONFIG_UART_INTERRUPT_DRIVEN */
static int uart_sifive_init(const struct device *dev)
{
const struct uart_sifive_device_config * const cfg = DEV_CFG(dev);
volatile struct uart_sifive_regs_t *uart = DEV_UART(dev);
/* Enable TX and RX channels */
uart->txctrl = TXCTRL_TXEN | CTRL_CNT(cfg->txcnt_irq);
uart->rxctrl = RXCTRL_RXEN | CTRL_CNT(cfg->rxcnt_irq);
/* Set baud rate */
uart->div = cfg->sys_clk_freq / cfg->baud_rate - 1;
#ifdef CONFIG_UART_INTERRUPT_DRIVEN
/* Ensure that uart IRQ is disabled initially */
uart->ie = 0U;
/* Setup IRQ handler */
cfg->cfg_func();
#endif
return 0;
}
static const struct uart_driver_api uart_sifive_driver_api = {
.poll_in = uart_sifive_poll_in,
.poll_out = uart_sifive_poll_out,
.err_check = NULL,
#ifdef CONFIG_UART_INTERRUPT_DRIVEN
.fifo_fill = uart_sifive_fifo_fill,
.fifo_read = uart_sifive_fifo_read,
.irq_tx_enable = uart_sifive_irq_tx_enable,
.irq_tx_disable = uart_sifive_irq_tx_disable,
.irq_tx_ready = uart_sifive_irq_tx_ready,
.irq_tx_complete = uart_sifive_irq_tx_complete,
.irq_rx_enable = uart_sifive_irq_rx_enable,
.irq_rx_disable = uart_sifive_irq_rx_disable,
.irq_rx_ready = uart_sifive_irq_rx_ready,
.irq_err_enable = uart_sifive_irq_err_enable,
.irq_err_disable = uart_sifive_irq_err_disable,
.irq_is_pending = uart_sifive_irq_is_pending,
.irq_update = uart_sifive_irq_update,
.irq_callback_set = uart_sifive_irq_callback_set,
#endif
};
#ifdef CONFIG_UART_SIFIVE_PORT_0
static struct uart_sifive_data uart_sifive_data_0;
#ifdef CONFIG_UART_INTERRUPT_DRIVEN
static void uart_sifive_irq_cfg_func_0(void);
#endif
static const struct uart_sifive_device_config uart_sifive_dev_cfg_0 = {
.port = DT_INST_REG_ADDR(0),
.sys_clk_freq = DT_INST_PROP(0, clock_frequency),
.baud_rate = DT_INST_PROP(0, current_speed),
.rxcnt_irq = CONFIG_UART_SIFIVE_PORT_0_RXCNT_IRQ,
.txcnt_irq = CONFIG_UART_SIFIVE_PORT_0_TXCNT_IRQ,
#ifdef CONFIG_UART_INTERRUPT_DRIVEN
.cfg_func = uart_sifive_irq_cfg_func_0,
#endif
};
DEVICE_DT_INST_DEFINE(0,
uart_sifive_init,
NULL,
&uart_sifive_data_0, &uart_sifive_dev_cfg_0,
PRE_KERNEL_1, CONFIG_KERNEL_INIT_PRIORITY_DEVICE,
(void *)&uart_sifive_driver_api);
#ifdef CONFIG_UART_INTERRUPT_DRIVEN
static void uart_sifive_irq_cfg_func_0(void)
{
IRQ_CONNECT(DT_INST_IRQN(0), DT_INST_IRQ(0, priority),
uart_sifive_irq_handler, DEVICE_DT_INST_GET(0),
0);
irq_enable(DT_INST_IRQN(0));
}
#endif
#endif /* CONFIG_UART_SIFIVE_PORT_0 */
#ifdef CONFIG_UART_SIFIVE_PORT_1
static struct uart_sifive_data uart_sifive_data_1;
#ifdef CONFIG_UART_INTERRUPT_DRIVEN
static void uart_sifive_irq_cfg_func_1(void);
#endif
static const struct uart_sifive_device_config uart_sifive_dev_cfg_1 = {
.port = DT_INST_REG_ADDR(1),
.sys_clk_freq = DT_INST_PROP(1, clock_frequency),
.baud_rate = DT_INST_PROP(1, current_speed),
.rxcnt_irq = CONFIG_UART_SIFIVE_PORT_1_RXCNT_IRQ,
.txcnt_irq = CONFIG_UART_SIFIVE_PORT_1_TXCNT_IRQ,
#ifdef CONFIG_UART_INTERRUPT_DRIVEN
.cfg_func = uart_sifive_irq_cfg_func_1,
#endif
};
DEVICE_DT_INST_DEFINE(1,
uart_sifive_init,
NULL,
&uart_sifive_data_1, &uart_sifive_dev_cfg_1,
PRE_KERNEL_1, CONFIG_KERNEL_INIT_PRIORITY_DEVICE,
(void *)&uart_sifive_driver_api);
#ifdef CONFIG_UART_INTERRUPT_DRIVEN
static void uart_sifive_irq_cfg_func_1(void)
{
IRQ_CONNECT(DT_INST_IRQN(1), DT_INST_IRQ(1, priority),
uart_sifive_irq_handler, DEVICE_DT_INST_GET(1),
0);
irq_enable(DT_INST_IRQN(1));
}
#endif
#endif /* CONFIG_UART_SIFIVE_PORT_1 */