aboutsummaryrefslogtreecommitdiff
path: root/src/platforms/stm32/usbuart.c
blob: 1c71105d373409bb9dd36405e6d809a2ca7488e0 (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
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
/*
 * This file is part of the Black Magic Debug project.
 *
 * Copyright (C) 2012  Black Sphere Technologies Ltd.
 * Written by Gareth McMullin <gareth@blacksphere.co.nz>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <libopencm3/stm32/rcc.h>
#include <libopencm3/stm32/gpio.h>
#include <libopencm3/stm32/usart.h>
#include <libopencm3/cm3/nvic.h>
#include <libopencm3/cm3/scs.h>
#include <libopencm3/usb/usbd.h>
#include <libopencm3/usb/cdc.h>

#include <platform.h>

void usbuart_init(void)
{
#if defined(BLACKMAGIC)
	/* On mini hardware, UART and SWD share connector pins.
	 * Don't enable UART if we're being debugged. */
	if ((platform_hwversion() == 1) && (SCS_DEMCR & SCS_DEMCR_TRCENA))
		return;
#endif

	rcc_peripheral_enable_clock(&USBUSART_APB_ENR, USBUSART_CLK_ENABLE);

	UART_PIN_SETUP();

	/* Setup UART parameters. */
	usart_set_baudrate(USBUSART, 38400);
	usart_set_databits(USBUSART, 8);
	usart_set_stopbits(USBUSART, USART_STOPBITS_1);
	usart_set_mode(USBUSART, USART_MODE_TX_RX);
	usart_set_parity(USBUSART, USART_PARITY_NONE);
	usart_set_flow_control(USBUSART, USART_FLOWCONTROL_NONE);

	/* Finally enable the USART. */
	usart_enable(USBUSART);

	/* Enable interrupts */
	USBUSART_CR1 |= USART_CR1_RXNEIE;
	nvic_set_priority(USBUSART_IRQ, IRQ_PRI_USBUSART);
	nvic_enable_irq(USBUSART_IRQ);
}

void usbuart_set_line_coding(struct usb_cdc_line_coding *coding)
{
	usart_set_baudrate(USBUSART, coding->dwDTERate);
	usart_set_databits(USBUSART, coding->bDataBits);
	switch(coding->bCharFormat) {
	case 0:
		usart_set_stopbits(USBUSART, USART_STOPBITS_1);
		break;
	case 1:
		usart_set_stopbits(USBUSART, USART_STOPBITS_1_5);
		break;
	case 2:
		usart_set_stopbits(USBUSART, USART_STOPBITS_2);
		break;
	}
	switch(coding->bParityType) {
	case 0:
		usart_set_parity(USBUSART, USART_PARITY_NONE);
		break;
	case 1:
		usart_set_parity(USBUSART, USART_PARITY_ODD);
		break;
	case 2:
		usart_set_parity(USBUSART, USART_PARITY_EVEN);
		break;
	}
}

void usbuart_usb_out_cb(usbd_device *dev, uint8_t ep)
{
	(void)ep;

	char buf[CDCACM_PACKET_SIZE];
	int len = usbd_ep_read_packet(dev, CDCACM_UART_ENDPOINT,
					buf, CDCACM_PACKET_SIZE);

#if defined(BLACKMAGIC)
	/* Don't bother if uart is disabled.
	 * This will be the case on mini while we're being debugged.
	 */
	if(!(RCC_APB2ENR & RCC_APB2ENR_USART1EN))
		return;
#endif

	gpio_set(LED_PORT_UART, LED_UART);
	for(int i = 0; i < len; i++)
		usart_send_blocking(USBUSART, buf[i]);
	gpio_clear(LED_PORT_UART, LED_UART);
}

static uint8_t uart_usb_buf[CDCACM_PACKET_SIZE];
static uint8_t uart_usb_buf_size;

void usbuart_usb_in_cb(usbd_device *dev, uint8_t ep)
{
	if (!uart_usb_buf_size) {
		gpio_clear(LED_PORT_UART, LED_UART);
		return;
	}

	usbd_ep_write_packet(dev, ep, uart_usb_buf, uart_usb_buf_size);
	uart_usb_buf_size = 0;
}

void USBUSART_ISR(void)
{
	char c = usart_recv(USBUSART);

	/* Don't try to write until we are configured.
	 * Otherwise enumeration hanged in some cases.
	 */
	if (cdcacm_get_config() != 1)
		return;

	gpio_set(LED_PORT_UART, LED_UART);

	/* Try to send now */
	if (usbd_ep_write_packet(usbdev, CDCACM_UART_ENDPOINT, &c, 1) == 1)
		return;

	/* We failed, so queue for later */
	if (uart_usb_buf_size == CDCACM_PACKET_SIZE) {
		/* Drop if the buffer's full: we have no flow control */
		return;
	}

	uart_usb_buf[uart_usb_buf_size++] = c;
}