blob: 8527e6c06474640d68fd0ce02b69b968d6ddef9b (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
|
/* Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
/* Interrupt based USART TX driver for STM32 */
#include "usart.h"
#include "common.h"
#include "registers.h"
#include "system.h"
#include "util.h"
static void usart_tx_init(struct usart_config const *config)
{
intptr_t base = config->hw->base;
STM32_USART_CR1(base) |= STM32_USART_CR1_TE;
}
static void usart_written(struct consumer const *consumer, size_t count)
{
struct usart_config const *config =
DOWNCAST(consumer, struct usart_config, consumer);
/*
* Enable USART interrupt. This causes the USART interrupt handler to
* start fetching from the TX queue if it wasn't already.
*/
if (count)
STM32_USART_CR1(config->hw->base) |= STM32_USART_CR1_TXEIE;
}
static void usart_tx_interrupt_handler(struct usart_config const *config)
{
intptr_t base = config->hw->base;
uint8_t byte;
if (!(STM32_USART_SR(base) & STM32_USART_SR_TXE))
return;
if (queue_remove_unit(config->consumer.queue, &byte)) {
STM32_USART_TDR(base) = byte;
/*
* Make sure the TXE interrupt is enabled and that we won't go
* into deep sleep. This invocation of the USART interrupt
* handler may have been manually triggered to start
* transmission.
*/
disable_sleep(SLEEP_MASK_UART);
STM32_USART_CR1(base) |= STM32_USART_CR1_TXEIE;
} else {
/*
* The TX queue is empty, disable the TXE interrupt and enable
* deep sleep mode. The TXE interrupt will remain disabled
* until a write call happens.
*/
enable_sleep(SLEEP_MASK_UART);
STM32_USART_CR1(base) &= ~STM32_USART_CR1_TXEIE;
}
}
struct usart_tx const usart_tx_interrupt = {
.consumer_ops = {
.written = usart_written,
},
.init = usart_tx_init,
.interrupt = usart_tx_interrupt_handler,
.info = NULL,
};
|
