stm32h7: usart: support new fifo features

Supported by H7 and G4 varieties at present.

lib/stm32/common/usart_common_fifos.c

@@ -0,0 +1,72 @@
+/*
+ * This file is part of the libopencm3 project.
+ *
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This library 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 Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <libopencm3/stm32/usart.h>
+
+void usart_enable_fifos(uint32_t usart) {
+	USART_CR1(usart) |= USART_CR1_FIFOEN;
+}
+
+void usart_disable_fifos(uint32_t usart) {
+	USART_CR1(usart) &= ~USART_CR1_FIFOEN;
+}
+
+void usart_enable_tx_fifo_empty_interrupt(uint32_t usart) {
+	USART_CR1(usart) |= USART_CR1_TXFEIE;
+}
+
+void usart_disable_tx_fifo_empty_interrupt(uint32_t usart) {
+	USART_CR1(usart) &= ~USART_CR1_TXFEIE;
+}
+
+void usart_enable_tx_fifo_threshold_interrupt(uint32_t usart) {
+	USART_CR3(usart) |= USART_CR3_TXFTIE;
+}
+
+void usart_disable_tx_fifo_threshold_interrupt(uint32_t usart) {
+	USART_CR3(usart) &= ~USART_CR3_TXFTIE;
+}
+
+void usart_set_tx_fifo_threshold(uint32_t usart,
+				 usart_fifo_threshold_t threshold) {
+	uint32_t cr3 = USART_CR3(usart) &
+		       ~(USART_FIFO_THRESH_MASK << USART_CR3_TXFTCFG_SHIFT);
+	USART_CR3(usart) = cr3 | (threshold << USART_CR3_TXFTCFG_SHIFT);
+}
+
+void usart_enable_rx_fifo_full_interrupt(uint32_t usart) {
+	USART_CR1(usart) |= USART_CR1_RXFFIE;
+}
+
+void usart_disable_rx_fifo_full_interrupt(uint32_t usart) {
+	USART_CR1(usart) &= ~USART_CR1_RXFFIE;
+}
+
+void usart_enable_rx_fifo_threshold_interrupt(uint32_t usart) {
+	USART_CR3(usart) |= USART_CR3_RXFTIE;
+}
+
+void usart_disable_rx_fifo_threshold_interrupt(uint32_t usart) {
+	USART_CR3(usart) &= ~USART_CR3_RXFTIE;
+}
+
+void usart_set_rx_fifo_threshold(uint32_t usart,
+				 usart_fifo_threshold_t threshold) {
+	uint32_t cr3 = USART_CR3(usart) &
+		       ~(USART_FIFO_THRESH_MASK << USART_CR3_RXFTCFG_SHIFT);
+	USART_CR3(usart) = cr3 | (threshold << USART_CR3_RXFTCFG_SHIFT);
+}

lib/stm32/h7/Makefile

@@ -45,7 +45,7 @@ OBJS += pwr.o rcc.o
 OBJS += rcc_common_all.o
 OBJS += spi_common_all.o spi_common_v2.o
 OBJS += timer_common_all.o
-OBJS += usart_common_all.o usart_common_v2.o
+OBJS += usart_common_all.o usart_common_v2.o usart_common_fifos.o
 
 VPATH += ../../usb:../:../../cm3:../common