--- /dev/null
+/*
+ * Copyright © 2019 Keith Packard <keithp@keithp.com>
+ *
+ * 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 2 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.
+ */
+
+#include <ao.h>
+
+static int
+_ao_usart_tx_start(struct ao_samd21_usart *usart)
+{
+ if (!ao_fifo_empty(usart->tx_fifo)) {
+#if HAS_SERIAL_SW_FLOW
+ if (usart->gpio_cts && ao_gpio_get(usart->gpio_cts, usart->pin_cts, foo) == 1) {
+ ao_exti_enable(usart->gpio_cts, usart->pin_cts);
+ return 0;
+ }
+#endif
+ if (usart->reg->intflag & (1 << SAMD21_SERCOM_INTFLAG_DRE))
+ {
+ usart->tx_running = 1;
+ usart->reg->intenset = (1 << SAMD21_SERCOM_INTFLAG_DRE) | (1 << SAMD21_SERCOM_INTFLAG_TXC);
+ ao_fifo_remove(usart->tx_fifo, usart->reg->data);
+ ao_wakeup(&usart->tx_fifo);
+ return 1;
+ }
+ }
+ return 0;
+}
+
+static void
+_ao_usart_rx(struct ao_samd21_usart *usart, int is_stdin)
+{
+ if (usart->reg->intflag & (1 << SAMD21_SERCOM_INTFLAG_RXC)) {
+ uint8_t data = (uint8_t) usart->reg->data;
+ if (!ao_fifo_full(usart->rx_fifo)) {
+ ao_fifo_insert(usart->rx_fifo, data);
+ ao_wakeup(&usart->rx_fifo);
+ if (is_stdin)
+ ao_wakeup(&ao_stdin_ready);
+#if HAS_SERIAL_SW_FLOW
+ /* If the fifo is nearly full, turn off RTS and wait
+ * for it to drain a bunch
+ */
+ if (usart->gpio_rts && ao_fifo_mostly(usart->rx_fifo)) {
+ ao_gpio_set(usart->gpio_rts, usart->pin_rts, usart->pin_rts, 1);
+ usart->rts = 0;
+ }
+#endif
+ }
+ }
+}
+
+static void
+ao_usart_isr(struct ao_samd21_usart *usart, int is_stdin)
+{
+ _ao_usart_rx(usart, is_stdin);
+
+ if (!_ao_usart_tx_start(usart))
+ usart->reg->intenclr = (1 << SAMD21_SERCOM_INTFLAG_DRE);
+
+ if (usart->reg->intflag & (1 << SAMD21_SERCOM_INTFLAG_TXC)) {
+ usart->tx_running = 0;
+ usart->reg->intenclr = (1 << SAMD21_SERCOM_INTFLAG_TXC);
+ if (usart->draining) {
+ usart->draining = 0;
+ ao_wakeup(&usart->tx_fifo);
+ }
+ }
+}
+
+static const uint32_t ao_usart_speeds[] = {
+ [AO_SERIAL_SPEED_4800] = 4800,
+ [AO_SERIAL_SPEED_9600] = 9600,
+ [AO_SERIAL_SPEED_19200] = 19200,
+ [AO_SERIAL_SPEED_57600] = 57600,
+ [AO_SERIAL_SPEED_115200] = 115200,
+};
+
+static void
+ao_usart_set_speed(struct ao_samd21_usart *usart, uint8_t speed)
+{
+ struct samd21_sercom *reg = usart->reg;
+ uint64_t top = (uint64_t) ao_usart_speeds[speed] << (4 + 16);
+ uint16_t baud = (uint16_t) (65536 - (top + AO_SYSCLK/2) / AO_SYSCLK);
+ uint32_t ctrla = reg->ctrla;
+
+ if (ctrla & (1UL << SAMD21_SERCOM_CTRLA_ENABLE)) {
+ usart->reg->ctrla = ctrla & ~(1UL << SAMD21_SERCOM_CTRLA_ENABLE);
+ while (reg->syncbusy & (1 << SAMD21_SERCOM_SYNCBUSY_ENABLE))
+ ;
+ }
+ usart->reg->baud = baud;
+ if (ctrla & (1UL << SAMD21_SERCOM_CTRLA_ENABLE)) {
+ usart->reg->ctrla = ctrla;
+ while (reg->syncbusy & (1 << SAMD21_SERCOM_SYNCBUSY_ENABLE))
+ ;
+ }
+}
+
+static void
+ao_usart_init(struct ao_samd21_usart *usart, bool hw_flow, uint8_t id, uint8_t txpo, uint8_t rxpo)
+{
+ struct samd21_sercom *reg = usart->reg;
+
+ (void) hw_flow;
+
+ /* Send a clock along */
+ samd21_gclk_clkctrl(0, SAMD21_GCLK_CLKCTRL_ID_SERCOM0_CORE + id);
+
+ samd21_nvic_set_enable(SAMD21_NVIC_ISR_SERCOM0_POS + id);
+ samd21_nvic_set_priority(SAMD21_NVIC_ISR_SERCOM0_POS + id, 4);
+
+ /* enable */
+ samd21_pm.apbcmask |= (1 << (SAMD21_PM_APBCMASK_SERCOM0 + id));
+
+ /* Reset */
+ reg->ctrla = (1 << SAMD21_SERCOM_CTRLA_SWRST);
+
+ while ((reg->ctrla & (1 << SAMD21_SERCOM_CTRLA_SWRST)) ||
+ (reg->syncbusy & (1 << SAMD21_SERCOM_SYNCBUSY_SWRST)))
+ ;
+
+ reg->ctrlb = ((0 << SAMD21_SERCOM_CTRLB_CHSIZE) |
+ (0 << SAMD21_SERCOM_CTRLB_SBMODE) |
+ (0 << SAMD21_SERCOM_CTRLB_COLDEN) |
+ (0 << SAMD21_SERCOM_CTRLB_SFDE) |
+ (0 << SAMD21_SERCOM_CTRLB_ENC) |
+ (0 << SAMD21_SERCOM_CTRLB_PMODE) |
+ (1 << SAMD21_SERCOM_CTRLB_TXEN) |
+ (1 << SAMD21_SERCOM_CTRLB_RXEN) |
+ (3 << SAMD21_SERCOM_CTRLB_FIFOCLR));
+
+ ao_usart_set_speed(usart, AO_SERIAL_SPEED_9600);
+
+ /* finish setup and enable the hardware */
+ reg->ctrla = ((0 << SAMD21_SERCOM_CTRLA_SWRST) |
+ (1 << SAMD21_SERCOM_CTRLA_ENABLE) |
+ (1 << SAMD21_SERCOM_CTRLA_MODE) |
+ (1 << SAMD21_SERCOM_CTRLA_RUNSTDBY) |
+ (0 << SAMD21_SERCOM_CTRLA_IBON) |
+ (0 << SAMD21_SERCOM_CTRLA_SAMPR) |
+ (txpo << SAMD21_SERCOM_CTRLA_TXPO) | /* pad[2] */
+ (rxpo << SAMD21_SERCOM_CTRLA_RXPO) | /* pad[3] */
+ (0 << SAMD21_SERCOM_CTRLA_SAMPA) |
+ (0 << SAMD21_SERCOM_CTRLA_FORM) | /* no parity */
+ (0 << SAMD21_SERCOM_CTRLA_CMODE) | /* async */
+ (0 << SAMD21_SERCOM_CTRLA_CPOL) |
+ (1 << SAMD21_SERCOM_CTRLA_DORD)); /* LSB first */
+
+ /* Enable receive interrupt */
+ reg->intenset = (1 << SAMD21_SERCOM_INTFLAG_RXC);
+
+ while (reg->syncbusy & (1 << SAMD21_SERCOM_SYNCBUSY_ENABLE))
+ ;
+
+}
+
+static int
+_ao_usart_pollchar(struct ao_samd21_usart *usart)
+{
+ int c;
+
+ if (ao_fifo_empty(usart->rx_fifo))
+ c = AO_READ_AGAIN;
+ else {
+ uint8_t u;
+ ao_fifo_remove(usart->rx_fifo, u);
+#if HAS_SERIAL_SW_FLOW
+ /* If we've cleared RTS, check if there's space now and turn it back on */
+ if (usart->gpio_rts && usart->rts == 0 && ao_fifo_barely(usart->rx_fifo)) {
+ ao_gpio_set(usart->gpio_rts, usart->pin_rts, foo, 0);
+ usart->rts = 1;
+ }
+#endif
+ c = u;
+ }
+ return c;
+}
+
+static char
+ao_usart_getchar(struct ao_samd21_usart *usart)
+{
+ int c;
+ ao_arch_block_interrupts();
+ while ((c = _ao_usart_pollchar(usart)) == AO_READ_AGAIN)
+ ao_sleep(&usart->rx_fifo);
+ ao_arch_release_interrupts();
+ return (char) c;
+}
+
+static void
+ao_usart_putchar(struct ao_samd21_usart *usart, char c)
+{
+ ao_arch_block_interrupts();
+ while (ao_fifo_full(usart->tx_fifo))
+ ao_sleep(&usart->tx_fifo);
+ ao_fifo_insert(usart->tx_fifo, c);
+ _ao_usart_tx_start(usart);
+ ao_arch_release_interrupts();
+}
+
+static void
+ao_usart_drain(struct ao_samd21_usart *usart)
+{
+ ao_arch_block_interrupts();
+ while (!ao_fifo_empty(usart->tx_fifo) || usart->tx_running) {
+ usart->draining = 1;
+ ao_sleep(&usart->tx_fifo);
+ }
+ ao_arch_release_interrupts();
+}
+
+#if HAS_SERIAL_0
+
+struct ao_samd21_usart ao_samd21_usart0;
+
+void samd21_sercom0_isr(void) { ao_usart_isr(&ao_samd21_usart0, USE_SERIAL_0_STDIN); }
+
+char
+ao_serial0_getchar(void)
+{
+ return ao_usart_getchar(&ao_samd21_usart0);
+}
+
+void
+ao_serial0_putchar(char c)
+{
+ ao_usart_putchar(&ao_samd21_usart0, c);
+}
+
+int
+_ao_serial0_pollchar(void)
+{
+ return _ao_usart_pollchar(&ao_samd21_usart0);
+}
+
+void
+ao_serial0_drain(void)
+{
+ ao_usart_drain(&ao_samd21_usart0);
+}
+
+void
+ao_serial0_set_speed(uint8_t speed)
+{
+ ao_usart_drain(&ao_samd21_usart0);
+ ao_usart_set_speed(&ao_samd21_usart0, speed);
+}
+#endif /* HAS_SERIAL_0 */
+
+#if HAS_SERIAL_1
+
+struct ao_samd21_usart ao_samd21_usart1;
+
+void samd21_sercom1_isr(void) { ao_usart_isr(&ao_samd21_usart1, USE_SERIAL_1_STDIN); }
+
+char
+ao_serial1_getchar(void)
+{
+ return ao_usart_getchar(&ao_samd21_usart1);
+}
+
+void
+ao_serial1_putchar(char c)
+{
+ ao_usart_putchar(&ao_samd21_usart1, c);
+}
+
+int
+_ao_serial1_pollchar(void)
+{
+ return _ao_usart_pollchar(&ao_samd21_usart1);
+}
+
+void
+ao_serial1_drain(void)
+{
+ ao_usart_drain(&ao_samd21_usart1);
+}
+
+void
+ao_serial1_set_speed(uint8_t speed)
+{
+ ao_usart_drain(&ao_samd21_usart1);
+ ao_usart_set_speed(&ao_samd21_usart1, speed);
+}
+#endif /* HAS_SERIAL_1 */
+
+void
+ao_serial_init(void)
+{
+ uint8_t txpo, rxpo;
+#if HAS_SERIAL_0
+
+#if SERIAL_0_PA10_PA11
+ /* Pin settings */
+ ao_enable_port(&samd21_port_a);
+ samd21_port_pmux_set(&samd21_port_a, 10, SAMD21_PORT_PMUX_FUNC_C);
+ samd21_port_pmux_set(&samd21_port_a, 11, SAMD21_PORT_PMUX_FUNC_C);
+ txpo = SAMD21_SERCOM_CTRLA_TXPO_TX_2; /* pad 2 */
+ rxpo = SAMD21_SERCOM_CTRLA_RXPO_RX_3; /* pad 3 */
+#elif SERIAL_0_PA08_PA09
+ /* Pin settings */
+ ao_enable_port(&samd21_port_a);
+ samd21_port_pmux_set(&samd21_port_a, 8, SAMD21_PORT_PMUX_FUNC_C);
+ samd21_port_pmux_set(&samd21_port_a, 9, SAMD21_PORT_PMUX_FUNC_C);
+ txpo = SAMD21_SERCOM_CTRLA_TXPO_TX_0; /* pad 0 */
+ rxpo = SAMD21_SERCOM_CTRLA_RXPO_RX_1; /* pad 1 */
+#else
+#error "No SERIAL_0 port configuration specified"
+#endif
+
+ ao_samd21_usart0.reg = &samd21_sercom0;
+ ao_usart_init(&ao_samd21_usart0, 0, 0, txpo, rxpo);
+
+#if USE_SERIAL_0_STDIN
+ ao_add_stdio(_ao_serial0_pollchar,
+ ao_serial0_putchar,
+ NULL);
+#endif
+#endif
+#if HAS_SERIAL_1
+
+#if SERIAL_1_PA00_PA01
+ /* Pin settings */
+ ao_enable_port(&samd21_port_a);
+ samd21_port_pmux_set(&samd21_port_a, 0, SAMD21_PORT_PMUX_FUNC_D);
+ samd21_port_pmux_set(&samd21_port_a, 1, SAMD21_PORT_PMUX_FUNC_D);
+ txpo = SAMD21_SERCOM_CTRLA_TXPO_TX_0;
+ rxpo = SAMD21_SERCOM_CTRLA_RXPO_RX_1;
+#else
+#error "No SERIAL_1 port configuration specified"
+#endif
+
+ ao_samd21_usart1.reg = &samd21_sercom1;
+ ao_usart_init(&ao_samd21_usart1, 0, 1, txpo, rxpo);
+
+#if USE_SERIAL_1_STDIN
+ ao_add_stdio(_ao_serial1_pollchar,
+ ao_serial1_putchar,
+ NULL);
+#endif
+#endif
+}
projects / fw / altos / blobdiff