--- /dev/null
+/*
+ * Copyright © 2020 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>
+#include <ao_exti.h>
+#include <ao_lpuart.h>
+
+struct ao_stm_lpuart {
+ struct ao_fifo rx_fifo;
+ struct ao_fifo tx_fifo;
+ struct stm_lpuart *reg;
+ 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_lpuart_tx_start(struct ao_stm_lpuart *lpuart)
+{
+ if (!ao_fifo_empty(lpuart->tx_fifo)) {
+#if HAS_LPUART_SW_FLOW
+ if (lpuart->gpio_cts && ao_gpio_get(lpuart->gpio_cts, lpuart->pin_cts) == 1) {
+ ao_exti_enable(lpuart->gpio_cts, lpuart->pin_cts);
+ return 0;
+ }
+#endif
+ if (lpuart->reg->isr & (1 << STM_LPUART_ISR_TXE))
+ {
+ lpuart->tx_running = 1;
+ lpuart->reg->cr1 |= (1 << STM_LPUART_CR1_TXEIE) | (1 << STM_LPUART_CR1_TCIE);
+ ao_fifo_remove(lpuart->tx_fifo, lpuart->reg->tdr);
+ ao_wakeup(&lpuart->tx_fifo);
+ return 1;
+ }
+ }
+ return 0;
+}
+
+#if HAS_LPUART_SW_FLOW
+static void
+_ao_lpuart_cts(struct ao_stm_lpuart *lpuart)
+{
+ if (_ao_lpuart_tx_start(lpuart))
+ ao_exti_disable(lpuart->gpio_cts, lpuart->pin_cts);
+}
+#endif
+
+static void
+_ao_lpuart_rx(struct ao_stm_lpuart *lpuart, int is_stdin)
+{
+ if (lpuart->reg->isr & (1 << STM_LPUART_ISR_RXNE)) {
+ lpuart->reg->icr = (1 << STM_LPUART_ICR_ORECF);
+ if (!ao_fifo_full(lpuart->rx_fifo)) {
+ ao_fifo_insert(lpuart->rx_fifo, lpuart->reg->rdr);
+ ao_wakeup(&lpuart->rx_fifo);
+ if (is_stdin)
+ ao_wakeup(&ao_stdin_ready);
+#if HAS_LPUART_SW_FLOW
+ /* If the fifo is nearly full, turn off RTS and wait
+ * for it to drain a bunch
+ */
+ if (lpuart->gpio_rts && ao_fifo_mostly(lpuart->rx_fifo)) {
+ ao_gpio_set(lpuart->gpio_rts, lpuart->pin_rts, 1);
+ lpuart->rts = 0;
+ }
+#endif
+ } else {
+ lpuart->reg->cr1 &= ~(1 << STM_LPUART_CR1_RXNEIE);
+ }
+ }
+}
+
+static void
+ao_lpuart_isr(struct ao_stm_lpuart *lpuart, int is_stdin)
+{
+ _ao_lpuart_rx(lpuart, is_stdin);
+
+ if (!_ao_lpuart_tx_start(lpuart))
+ lpuart->reg->cr1 &= ~(1<< STM_LPUART_CR1_TXEIE);
+
+ if (lpuart->reg->isr & (1 << STM_LPUART_ISR_TC)) {
+ lpuart->tx_running = 0;
+ lpuart->reg->cr1 &= ~(1 << STM_LPUART_CR1_TCIE);
+ if (lpuart->draining) {
+ lpuart->draining = 0;
+ ao_wakeup(&lpuart->tx_fifo);
+ }
+ }
+}
+
+static int
+_ao_lpuart_pollchar(struct ao_stm_lpuart *lpuart)
+{
+ int c;
+
+ if (ao_fifo_empty(lpuart->rx_fifo))
+ c = AO_READ_AGAIN;
+ else {
+ uint8_t u;
+ ao_fifo_remove(lpuart->rx_fifo,u);
+ if ((lpuart->reg->cr1 & (1 << STM_LPUART_CR1_RXNEIE)) == 0) {
+ if (ao_fifo_barely(lpuart->rx_fifo))
+ lpuart->reg->cr1 |= (1 << STM_LPUART_CR1_RXNEIE);
+ }
+#if HAS_LPUART_SW_FLOW
+ /* If we've cleared RTS, check if there's space now and turn it back on */
+ if (lpuart->gpio_rts && lpuart->rts == 0 && ao_fifo_barely(lpuart->rx_fifo)) {
+ ao_gpio_set(lpuart->gpio_rts, lpuart->pin_rts, 0);
+ lpuart->rts = 1;
+ }
+#endif
+ c = u;
+ }
+ return c;
+}
+
+static char
+ao_lpuart_getchar(struct ao_stm_lpuart *lpuart)
+{
+ int c;
+ ao_arch_block_interrupts();
+ while ((c = _ao_lpuart_pollchar(lpuart)) == AO_READ_AGAIN)
+ ao_sleep(&lpuart->rx_fifo);
+ ao_arch_release_interrupts();
+ return (char) c;
+}
+
+#if 0
+static inline uint8_t
+_ao_lpuart_sleep_for(struct ao_stm_lpuart *lpuart, uint16_t timeout)
+{
+ return ao_sleep_for(&lpuart->rx_fifo, timeout);
+}
+#endif
+
+static void
+ao_lpuart_putchar(struct ao_stm_lpuart *lpuart, char c)
+{
+ ao_arch_block_interrupts();
+ while (ao_fifo_full(lpuart->tx_fifo))
+ ao_sleep(&lpuart->tx_fifo);
+ ao_fifo_insert(lpuart->tx_fifo, c);
+ _ao_lpuart_tx_start(lpuart);
+ ao_arch_release_interrupts();
+}
+
+static void
+ao_lpuart_drain(struct ao_stm_lpuart *lpuart)
+{
+ ao_arch_block_interrupts();
+ while (!ao_fifo_empty(lpuart->tx_fifo) || lpuart->tx_running) {
+ lpuart->draining = 1;
+ ao_sleep(&lpuart->tx_fifo);
+ }
+ ao_arch_release_interrupts();
+}
+
+extern const uint32_t ao_usart_speeds[];
+
+static void
+ao_lpuart_set_speed(struct ao_stm_lpuart *lpuart, uint8_t speed)
+{
+ if (speed > AO_SERIAL_SPEED_115200)
+ return;
+ lpuart->reg->brr = AO_PCLK1 / ao_usart_speeds[speed];
+}
+
+static void
+ao_lpuart_enable(struct ao_stm_lpuart *lpuart, int hw_flow)
+{
+ lpuart->reg->cr1 = ((0 << STM_LPUART_CR1_M1) |
+ (0 << STM_LPUART_CR1_DEAT) |
+ (0 << STM_LPUART_CR1_DEDT) |
+ (0 << STM_LPUART_CR1_CMIE) |
+ (0 << STM_LPUART_CR1_MME) |
+ (0 << STM_LPUART_CR1_M0) |
+ (0 << STM_LPUART_CR1_WAKE) |
+ (0 << STM_LPUART_CR1_PCE) |
+ (0 << STM_LPUART_CR1_PS) |
+ (0 << STM_LPUART_CR1_PEIE) |
+ (0 << STM_LPUART_CR1_TXEIE) |
+ (0 << STM_LPUART_CR1_TCIE) |
+ (1 << STM_LPUART_CR1_RXNEIE) |
+ (0 << STM_LPUART_CR1_IDLEIE) |
+ (1 << STM_LPUART_CR1_TE) |
+ (1 << STM_LPUART_CR1_RE) |
+ (0 << STM_LPUART_CR1_UESM) |
+ (0 << STM_LPUART_CR1_UE));
+
+ lpuart->reg->cr2 = ((0 << STM_LPUART_CR2_ADD) |
+ (0 << STM_LPUART_CR2_MSBFIRST) |
+ (0 << STM_LPUART_CR2_DATAINV) |
+ (0 << STM_LPUART_CR2_TXINV) |
+ (0 << STM_LPUART_CR2_RXINV) |
+ (0 << STM_LPUART_CR2_SWAP) |
+ (0 << STM_LPUART_CR2_STOP) |
+ (0 << STM_LPUART_CR2_ADDM7));
+
+ uint32_t cr3 = ((0 << STM_LPUART_CR3_UCESM) |
+ (0 << STM_LPUART_CR3_WUFIE) |
+ (0 << STM_LPUART_CR3_WUS) |
+ (0 << STM_LPUART_CR3_DEP) |
+ (0 << STM_LPUART_CR3_DEM) |
+ (0 << STM_LPUART_CR3_DDRE) |
+ (0 << STM_LPUART_CR3_OVRDIS) |
+ (0 << STM_LPUART_CR3_CTSIE) |
+ (0 << STM_LPUART_CR3_CTSE) |
+ (0 << STM_LPUART_CR3_RTSE) |
+ (0 << STM_LPUART_CR3_DMAT) |
+ (0 << STM_LPUART_CR3_DMAR) |
+ (0 << STM_LPUART_CR3_HDSEL) |
+ (0 << STM_LPUART_CR3_EIE));
+
+ if (hw_flow)
+ cr3 |= ((1 << STM_LPUART_CR3_CTSE) |
+ (1 << STM_LPUART_CR3_RTSE));
+
+ lpuart->reg->cr3 = cr3;
+
+ /* Pick a 9600 baud rate */
+ ao_lpuart_set_speed(lpuart, AO_SERIAL_SPEED_9600);
+
+ /* Enable the lpuart */
+ lpuart->reg->cr1 |= (1 << STM_LPUART_CR1_UE);
+}
+
+static void
+ao_lpuart_disable(struct ao_stm_lpuart *lpuart)
+{
+ ao_lpuart_drain(lpuart);
+ lpuart->reg->cr1 = 0;
+}
+
+#if HAS_LPUART_1
+
+struct ao_stm_lpuart ao_stm_lpuart1;
+
+void stm_lpuart1_aes_isr(void) {
+ ao_lpuart_isr(&ao_stm_lpuart1, USE_LPUART_1_STDIN);
+}
+
+char
+ao_lpuart1_getchar(void)
+{
+ return ao_lpuart_getchar(&ao_stm_lpuart1);
+}
+
+void
+ao_lpuart1_putchar(char c)
+{
+ ao_lpuart_putchar(&ao_stm_lpuart1, c);
+}
+
+int
+_ao_lpuart1_pollchar(void)
+{
+ return _ao_lpuart_pollchar(&ao_stm_lpuart1);
+}
+
+void
+ao_lpuart1_drain(void)
+{
+ ao_lpuart_drain(&ao_stm_lpuart1);
+}
+
+void
+ao_lpuart1_set_speed(uint8_t speed)
+{
+ ao_lpuart_drain(&ao_stm_lpuart1);
+ ao_lpuart_set_speed(&ao_stm_lpuart1, speed);
+}
+
+#endif /* HAS_LPUART_1 */
+
+#if HAS_LPUART_SW_FLOW
+static void
+ao_lpuart_set_sw_rts_cts(struct ao_stm_lpuart *lpuart,
+ 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);
+ lpuart->gpio_rts = port_rts;
+ lpuart->pin_rts = pin_rts;
+ lpuart->rts = 1;
+
+ ao_exti_setup(port_cts, pin_cts, AO_EXTI_MODE_FALLING|AO_EXTI_PRIORITY_MED, isr);
+ lpuart->gpio_cts = port_cts;
+ lpuart->pin_cts = pin_cts;
+}
+#endif
+
+void
+ao_lpuart1_enable(void)
+{
+ /*
+ * TX RX
+ * PA1 PA0
+ * PA2 PA3
+ * PA4 PA3
+ * PA14 PA13
+ * PB6 PB7
+ */
+
+#ifdef HAS_LPUART_1
+ /* Clock source defaults to PCLK1, so just leave it */
+
+# if LPUART_1_PA0_PA1
+ ao_enable_port(&stm_gpioa);
+ stm_afr_set(&stm_gpioa, 0, STM_AFR_AF6);
+ stm_afr_set(&stm_gpioa, 1, STM_AFR_AF6);
+# else
+# error "No LPUART_1 port configuration specified"
+# endif
+ /* Enable LPUART */
+ stm_rcc.apb1enr |= (1 << STM_RCC_APB1ENR_LPUART1EN);
+
+ ao_stm_lpuart1.reg = &stm_lpuart1;
+ ao_lpuart_enable(&ao_stm_lpuart1, USE_LPUART_1_FLOW && !USE_LPUART_1_SW_FLOW);
+
+ stm_nvic_set_enable(STM_ISR_LPUART1_AES_POS);
+ stm_nvic_set_priority(STM_ISR_LPUART1_AES_POS, 4);
+# if USE_LPUART_1_STDIN && !DELAY_LPUART_1_STDIN
+ ao_add_stdio(_ao_lpuart1_pollchar,
+ ao_lpuart1_putchar,
+ NULL);
+# endif
+#endif
+}
+
+void
+ao_lpuart1_disable(void)
+{
+ /* Disable interrupts */
+ stm_nvic_clear_enable(STM_ISR_LPUART1_AES_POS);
+
+ /* Stop LPUART */
+ ao_lpuart_disable(&ao_stm_lpuart1);
+
+ /* Remap pins to GPIO use */
+# if LPUART_1_PA0_PA1
+ stm_afr_set(&stm_gpioa, 0, STM_AFR_NONE);
+ stm_afr_set(&stm_gpioa, 1, STM_AFR_NONE);
+# else
+# error "No LPUART_1 port configuration specified"
+# endif
+
+ /* Disable LPUART */
+ stm_rcc.apb1enr &= ~(1 << STM_RCC_APB1ENR_LPUART1EN);
+}
projects / fw / altos / blobdiff