--- /dev/null
+/*
+ * Copyright © 2018 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.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ */
+
+#include <ao.h>
+#include <ao_exti.h>
+
+/* ao_serial_stm.c */
+struct ao_stm_usart {
+ struct ao_fifo rx_fifo;
+ struct ao_fifo tx_fifo;
+ struct stm_usart *reg;
+ uint32_t clk;
+ uint8_t tx_running;
+ uint8_t draining;
+#if HAS_SERIAL_SW_FLOW
+ /* RTS - 0 if we have FIFO space, 1 if not
+ * CTS - 0 if we can send, 0 if not
+ */
+ struct stm_gpio *gpio_rts;
+ struct stm_gpio *gpio_cts;
+ uint8_t pin_rts;
+ uint8_t pin_cts;
+ uint8_t rts;
+#endif
+};
+
+static int
+_ao_usart_tx_start(struct ao_stm_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) == 1) {
+ ao_exti_enable(usart->gpio_cts, usart->pin_cts);
+ return 0;
+ }
+#endif
+ if (usart->reg->sr & (1 << STM_USART_SR_TXE))
+ {
+ usart->tx_running = 1;
+ usart->reg->cr1 |= (1 << STM_USART_CR1_TXEIE) | (1 << STM_USART_CR1_TCIE);
+ ao_fifo_remove(usart->tx_fifo, usart->reg->dr);
+ ao_wakeup(&usart->tx_fifo);
+ return 1;
+ }
+ }
+ return 0;
+}
+
+#if HAS_SERIAL_SW_FLOW
+static void
+_ao_usart_cts(struct ao_stm_usart *usart)
+{
+ if (_ao_usart_tx_start(usart))
+ ao_exti_disable(usart->gpio_cts, usart->pin_cts);
+}
+#endif
+
+static void
+_ao_usart_rx(struct ao_stm_usart *usart, int is_stdin)
+{
+ if (usart->reg->sr & (1 << STM_USART_SR_RXNE)) {
+ if (!ao_fifo_full(usart->rx_fifo)) {
+ ao_fifo_insert(usart->rx_fifo, usart->reg->dr);
+ 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, 1);
+ usart->rts = 0;
+ }
+#endif
+ } else {
+ usart->reg->cr1 &= ~(1 << STM_USART_CR1_RXNEIE);
+ }
+ }
+}
+
+static void
+ao_usart_isr(struct ao_stm_usart *usart, int is_stdin)
+{
+ _ao_usart_rx(usart, is_stdin);
+
+ if (!_ao_usart_tx_start(usart))
+ usart->reg->cr1 &= ~(1<< STM_USART_CR1_TXEIE);
+
+ if (usart->reg->sr & (1 << STM_USART_SR_TC)) {
+ usart->tx_running = 0;
+ usart->reg->cr1 &= ~(1 << STM_USART_CR1_TCIE);
+ if (usart->draining) {
+ usart->draining = 0;
+ ao_wakeup(&usart->tx_fifo);
+ }
+ }
+}
+
+static int
+_ao_usart_pollchar(struct ao_stm_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 ((usart->reg->cr1 & (1 << STM_USART_CR1_RXNEIE)) == 0) {
+ if (ao_fifo_barely(usart->rx_fifo))
+ usart->reg->cr1 |= (1 << STM_USART_CR1_RXNEIE);
+ }
+#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, 0);
+ usart->rts = 1;
+ }
+#endif
+ c = u;
+ }
+ return c;
+}
+
+static char
+ao_usart_getchar(struct ao_stm_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 inline uint8_t
+_ao_usart_sleep_for(struct ao_stm_usart *usart, uint16_t timeout)
+{
+ return ao_sleep_for(&usart->rx_fifo, timeout);
+}
+
+static void
+ao_usart_putchar(struct ao_stm_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_stm_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();
+}
+
+static void
+ao_usart_set_speed(struct ao_stm_usart *usart, uint32_t speed)
+{
+ if (speed > 115200)
+ return;
+ usart->reg->brr = usart->clk / speed;
+}
+
+static void
+_ao_usart_init(struct ao_stm_usart *usart, int hw_flow)
+{
+ usart->reg->cr1 = ((0 << STM_USART_CR1_OVER8) |
+ (1 << STM_USART_CR1_UE) |
+ (0 << STM_USART_CR1_M) |
+ (0 << STM_USART_CR1_WAKE) |
+ (0 << STM_USART_CR1_PCE) |
+ (0 << STM_USART_CR1_PS) |
+ (0 << STM_USART_CR1_PEIE) |
+ (0 << STM_USART_CR1_TXEIE) |
+ (0 << STM_USART_CR1_TCIE) |
+ (1 << STM_USART_CR1_RXNEIE) |
+ (0 << STM_USART_CR1_IDLEIE) |
+ (1 << STM_USART_CR1_TE) |
+ (1 << STM_USART_CR1_RE) |
+ (0 << STM_USART_CR1_RWU) |
+ (0 << STM_USART_CR1_SBK));
+
+ usart->reg->cr2 = ((0 << STM_USART_CR2_LINEN) |
+ (STM_USART_CR2_STOP_1 << STM_USART_CR2_STOP) |
+ (0 << STM_USART_CR2_CLKEN) |
+ (0 << STM_USART_CR2_CPOL) |
+ (0 << STM_USART_CR2_CPHA) |
+ (0 << STM_USART_CR2_LBCL) |
+ (0 << STM_USART_CR2_LBDIE) |
+ (0 << STM_USART_CR2_LBDL) |
+ (0 << STM_USART_CR2_ADD));
+
+ usart->reg->cr3 = ((0 << STM_USART_CR3_ONEBIT) |
+ (0 << STM_USART_CR3_CTSIE) |
+ (0 << STM_USART_CR3_CTSE) |
+ (0 << STM_USART_CR3_RTSE) |
+ (0 << STM_USART_CR3_DMAT) |
+ (0 << STM_USART_CR3_DMAR) |
+ (0 << STM_USART_CR3_SCEN) |
+ (0 << STM_USART_CR3_NACK) |
+ (0 << STM_USART_CR3_HDSEL) |
+ (0 << STM_USART_CR3_IRLP) |
+ (0 << STM_USART_CR3_IREN) |
+ (0 << STM_USART_CR3_EIE));
+
+ if (hw_flow)
+ usart->reg->cr3 |= ((1 << STM_USART_CR3_CTSE) |
+ (1 << STM_USART_CR3_RTSE));
+
+ /* Pick a 9600 baud rate */
+ ao_usart_set_speed(usart, 9600);
+}
+
+#if HAS_SERIAL_HW_FLOW
+static void
+ao_usart_set_flow(struct ao_stm_usart *usart)
+{
+}
+#endif
+
+#if HAS_SERIAL_6
+
+struct ao_stm_usart ao_stm_usart6;
+
+void stm_usart6_isr(void) { ao_usart_isr(&ao_stm_usart6, USE_SERIAL_6_STDIN); }
+
+char
+ao_serial6_getchar(void)
+{
+ return ao_usart_getchar(&ao_stm_usart6);
+}
+
+void
+ao_serial6_putchar(char c)
+{
+ ao_usart_putchar(&ao_stm_usart6, c);
+}
+
+int
+_ao_serial6_pollchar(void)
+{
+ return _ao_usart_pollchar(&ao_stm_usart6);
+}
+
+uint8_t
+_ao_serial6_sleep_for(uint16_t timeout)
+{
+ return _ao_usart_sleep_for(&ao_stm_usart6, timeout);
+}
+
+void
+ao_serial6_set_speed(uint32_t speed)
+{
+ ao_usart_drain(&ao_stm_usart6);
+ ao_usart_set_speed(&ao_stm_usart6, speed);
+}
+
+void
+ao_serial6_drain(void)
+{
+ ao_usart_drain(&ao_stm_usart6);
+}
+#endif /* HAS_SERIAL_6 */
+
+#if HAS_SERIAL_SW_FLOW
+static void
+ao_serial_set_sw_rts_cts(struct ao_stm_usart *usart,
+ void (*isr)(void),
+ struct stm_gpio *port_rts,
+ int pin_rts,
+ struct stm_gpio *port_cts,
+ int pin_cts)
+{
+ /* Pull RTS low to note that there's space in the FIFO */
+ ao_enable_output(port_rts, pin_rts, 0);
+ usart->gpio_rts = port_rts;
+ usart->pin_rts = pin_rts;
+ usart->rts = 1;
+
+ ao_exti_setup(port_cts, pin_cts, AO_EXTI_MODE_FALLING|AO_EXTI_PRIORITY_MED, isr);
+ usart->gpio_cts = port_cts;
+ usart->pin_cts = pin_cts;
+}
+#endif
+
+void
+ao_usart_init(void)
+{
+#if HAS_SERIAL_6
+ stm_rcc.apb2enr |= (1 << STM_RCC_APB2ENR_USART6EN);
+
+ ao_stm_usart6.reg = &stm_usart6;
+ ao_stm_usart6.clk = AO_P2CLK;
+
+ ao_enable_port(SERIAL_6_RX_PORT);
+ ao_enable_port(SERIAL_6_TX_PORT);
+
+ stm_afr_set(SERIAL_6_RX_PORT, SERIAL_6_RX_PIN, STM_AFR_AF8);
+ stm_afr_set(SERIAL_6_TX_PORT, SERIAL_6_TX_PIN, STM_AFR_AF8);
+
+ stm_nvic_set_enable(STM_ISR_USART6_POS);
+ stm_nvic_set_priority(STM_ISR_USART6_POS, AO_STM_NVIC_MED_PRIORITY);
+
+ _ao_usart_init(&ao_stm_usart6, USE_SERIAL_6_FLOW && !USE_SERIAL_6_SW_FLOW);
+
+# if USE_SERIAL_6_FLOW
+# if USE_SERIAL_6_SW_FLOW
+ ao_serial_set_sw_rts_cts(&ao_stm_usart6,
+ ao_serial6_cts,
+ SERIAL_6_PORT_RTS,
+ SERIAL_6_PIN_RTS,
+ SERIAL_6_PORT_CTS,
+ SERIAL_6_PIN_CTS);
+# else
+ stm_afr_set(SERIAL_6_PORT_RTS, SERIAL_6_PIN_RTS, STM_AFR_AF8);
+ stm_afr_set(SERIAL_6_PORT_CTS, SERIAL_6_PIN_CTS, STM_AFR_AF8);
+# endif
+#endif
+
+#if USE_SERIAL_6_STDIN && !DELAY_SERIAL_6_STDIN
+ ao_add_stdio(_ao_serial6_pollchar,
+ ao_serial6_putchar,
+ NULL);
+#endif
+#endif
+}
projects / fw / altos / blobdiff