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drivers: serial: add LiteUART driver

Add LiteX UART driver with bindings for this device.

Signed-off-by: Filip Kokosinski <fkokosinski@internships.antmicro.com>
Signed-off-by: Mateusz Holenko <mholenko@antmicro.com>
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fkokosinski authored and galak committed Mar 28, 2019
1 parent 0472bc4 commit b3739169cb0e250f7a380af1bedb8d72f173fdbe
@@ -137,6 +137,8 @@
/drivers/sensor/lsm*/ @avisconti
/drivers/serial/uart_altera_jtag_hal.c @wentongwu
/drivers/serial/*ns16550* @gnuless
/drivers/serial/Kconfig.litex @mateusz-holenko @kgugala @pgielda
/drivers/serial/uart_liteuart.c @mateusz-holenko @kgugala @pgielda
/drivers/net/ @jukkar @tbursztyka
/drivers/ptp_clock/ @jukkar
/drivers/spi/ @tbursztyka
@@ -170,6 +172,7 @@
/dts/bindings/*/st* @erwango
/dts/bindings/sensor/ams* @alexanderwachter
/dts/bindings/*/sifive* @mateusz-holenko @kgugala @pgielda @nategraff-sifive
/dts/bindings/*/litex* @mateusz-holenko @kgugala @pgielda
/ext/fs/ @nashif @wentongwu
/ext/hal/atmel/asf/sam/include/same70*/ @aurel32
/ext/hal/atmel/asf/sam0/include/samr21/ @benpicco
@@ -28,6 +28,7 @@ zephyr_library_sources_if_kconfig(usart_mcux_lpc.c)
zephyr_library_sources_if_kconfig(uart_psoc6.c)
zephyr_library_sources_if_kconfig(uart_pl011.c)
zephyr_library_sources_if_kconfig(uart_rv32m1_lpuart.c)
zephyr_library_sources_if_kconfig(uart_liteuart.c)

zephyr_library_sources_ifdef(CONFIG_USERSPACE uart_handlers.c)

@@ -116,4 +116,6 @@ source "drivers/serial/Kconfig.pl011"

source "drivers/serial/Kconfig.rv32m1_lpuart"

source "drivers/serial/Kconfig.litex"

endif # SERIAL
@@ -0,0 +1,22 @@
# Kconfig.litex - LiteX UART (LiteUART) configuration option
#
# Copyright (c) 2018 - 2019 Antmicro <www.antmicro.com>
#
# SPDX-License-Identifier: Apache-2.0
#

menuconfig UART_LITEUART
bool "LiteUART serial driver"
depends on SOC_RISCV32_LITEX_VEXRISCV
# currently not supporting interrupts due to a bug in LiteUART Tx IRQ
depends on !SERIAL_SUPPORT_INTERRUPT
select SERIAL_HAS_DRIVER
help
This option enables LiteUART serial driver.

menuconfig UART_LITEUART_PORT_0
bool "Enable LiteX Port 0"
depends on UART_LITEUART
help
This tells the driver to configure the UART port at boot, depending on
the additional configuration options below.
@@ -0,0 +1,337 @@
/*
* Copyright (c) 2018 - 2019 Antmicro <www.antmicro.com>
*
* SPDX-License-Identifier: Apache-2.0
*/

#include <kernel.h>
#include <arch/cpu.h>
#include <init.h>
#include <irq.h>
#include <device.h>
#include <uart.h>
#include <zephyr/types.h>

#define UART_EV_TX (1 << 0)
#define UART_EV_RX (1 << 1)
#define UART_BASE_ADDR DT_LITEX_UART0_E0001800_BASE_ADDRESS
#define UART_RXTX ((UART_BASE_ADDR) + 0x00)
#define UART_TXFULL ((UART_BASE_ADDR) + 0x04)
#define UART_RXEMPTY ((UART_BASE_ADDR) + 0x08)
#define UART_EV_STATUS ((UART_BASE_ADDR) + 0x0c)
#define UART_EV_PENDING ((UART_BASE_ADDR) + 0x10)
#define UART_EV_ENABLE ((UART_BASE_ADDR) + 0x14)
#define UART_IRQ DT_LITEX_UART0_E0001800_IRQ_0

#ifdef CONFIG_UART_INTERRUPT_DRIVEN
typedef void (*irq_cfg_func_t)(void);
#endif

struct uart_liteuart_device_config {
u32_t port;
u32_t sys_clk_freq;
u32_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(struct device *dev, unsigned char c)
{
/* wait for space */
while (sys_read8(UART_TXFULL))
;

sys_write8(c, UART_RXTX);
}

/**
* @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(struct device *dev, unsigned char *c)
{
if (!sys_read8(UART_RXEMPTY)) {
*c = sys_read8(UART_RXTX);

/* refresh UART_RXEMPTY by writing UART_EV_RX
* to UART_EV_PENDING
*/
sys_write8(UART_EV_RX, UART_EV_PENDING);
return 0;
} else {
return -1;
}
}

#ifdef CONFIG_UART_INTERRUPT_DRIVEN
/**
* @brief Enable TX interrupt in event register
*
* @param dev UART device struct
*
* @return N/A
*/
static void uart_liteuart_irq_tx_enable(struct device *dev)
{
u8_t enable = sys_read8(UART_EV_ENABLE);

sys_write8(enable | UART_EV_TX, UART_EV_ENABLE);
}

/**
* @brief Disable TX interrupt in event register
*
* @param dev UART device struct
*
* @return N/A
*/
static void uart_liteuart_irq_tx_disable(struct device *dev)
{
u8_t enable = sys_read8(UART_EV_ENABLE);

sys_write8(enable & ~(UART_EV_TX), UART_EV_ENABLE);
}

/**
* @brief Enable RX interrupt in event register
*
* @param dev UART device struct
*
* @return N/A
*/
static void uart_liteuart_irq_rx_enable(struct device *dev)
{
u8_t enable = sys_read8(UART_EV_ENABLE);

sys_write8(enable | UART_EV_RX, UART_EV_ENABLE);
}

/**
* @brief Disable RX interrupt in event register
*
* @param dev UART device struct
*
* @return N/A
*/
static void uart_liteuart_irq_rx_disable(struct device *dev)
{
u8_t enable = sys_read8(UART_EV_ENABLE);

sys_write8(enable & ~(UART_EV_RX), UART_EV_ENABLE);
}

/**
* @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(struct device *dev)
{
u8_t val = sys_read8(UART_TXFULL);

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(struct device *dev)
{
u8_t pending;

pending = sys_read8(UART_EV_PENDING);

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(struct device *dev,
const u8_t *tx_data, int size)
{
int i;

for (i = 0; i < size && !sys_read8(UART_TXFULL); i++) {
sys_write8(tx_data[i], UART_RXTX);
}

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(struct device *dev,
u8_t *rx_data, const int size)
{
int i;

for (i = 0; i < size && !sys_read8(UART_RXEMPTY); i++) {
rx_data[i] = sys_read8(UART_RXTX);

/* refresh UART_RXEMPTY by writing UART_EV_RX
* to UART_EV_PENDING
*/
sys_write8(UART_EV_RX, UART_EV_PENDING);
}

return i;
}

static void uart_liteuart_irq_err(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(struct device *dev)
{
u8_t pending;

pending = sys_read8(UART_EV_PENDING);

if (pending & (UART_EV_TX | UART_EV_RX)) {
return 1;
} else {
return 0;
}
}

static int uart_liteuart_irq_update(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_liteuart_irq_callback_set(struct device *dev,
uart_irq_callback_user_data_t cb,
void *cb_data)
{
struct uart_liteuart_data *data;

data = (struct uart_liteuart_data *)dev->driver_data;
data->callback = cb;
data->cb_data = cb_data;
}

static void liteuart_uart_irq_handler(void *arg)
{
struct device *dev = (struct device *)arg;
struct uart_liteuart_data *data = DEV_DATA(dev);
int key = irq_lock();

if (data->callback) {
data->callback(data->cb_data);
}

/* clear events */
sys_write8(UART_EV_TX | UART_EV_RX, UART_EV_PENDING);

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(struct device *dev);

static const struct uart_liteuart_device_config uart_liteuart_dev_cfg_0 = {
.port = UART_BASE_ADDR,
.baud_rate = DT_LITEX_UART0_E0001800_CURRENT_SPEED
};

DEVICE_AND_API_INIT(uart_liteuart_0, DT_LITEX_UART0_E0001800_LABEL,
uart_liteuart_init,
&uart_liteuart_data_0, &uart_liteuart_dev_cfg_0,
PRE_KERNEL_1, CONFIG_KERNEL_INIT_PRIORITY_DEVICE,
(void *)&uart_liteuart_driver_api);

static int uart_liteuart_init(struct device *dev)
{
sys_write8(UART_EV_TX | UART_EV_RX, UART_EV_PENDING);

#ifdef CONFIG_UART_INTERRUPT_DRIVEN
IRQ_CONNECT(UART_IRQ, DT_LITEX_UART0_E0001800_IRQ_0_PRIORITY,
liteuart_uart_irq_handler, DEVICE_GET(uart_liteuart_0),
0);
irq_enable(UART_IRQ);
#endif

return 0;
}

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