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/* Copyright 2020 The ChromiumOS Authors
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
/* Interrupt based USART RX driver for STM32F0 and STM32F4 */
#include "usart.h"
#include "atomic.h"
#include "common.h"
#include "queue.h"
#include "registers.h"
static void usart_rx_init(struct usart_config const *config)
{
intptr_t base = config->hw->base;
STM32_USART_CR1(base) |= STM32_USART_CR1_RXNEIE;
STM32_USART_CR1(base) |= STM32_USART_CR1_RE;
#if defined(CHIP_FAMILY_STM32F0) || defined(CHIP_FAMILY_STM32F3) || \
defined(CHIP_FAMILY_STM32L4)
STM32_USART_CR3(base) |= STM32_USART_CR3_OVRDIS;
#endif
}
static void usart_rx_interrupt_handler(struct usart_config const *config)
{
intptr_t base = config->hw->base;
int32_t status = STM32_USART_SR(base);
if (status & STM32_USART_SR_RXNE) {
uint8_t byte = STM32_USART_RDR(base);
if (!queue_add_unit(config->producer.queue, &byte))
atomic_add((atomic_t *)&(config->state->rx_dropped), 1);
}
}
struct usart_rx const usart_rx_interrupt = {
.producer_ops = {
/*
* Nothing to do here, we either had enough space in the queue
* when a character came in or we dropped it already.
*/
.read = NULL,
},
.init = usart_rx_init,
.interrupt = usart_rx_interrupt_handler,
.info = NULL,
};
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