Add ring buffer for uart TX

stm-firmware/include/uart/dma-ring-buffer.h

@@ -14,9 +14,26 @@ struct dma_ring_buffer_to_mem {
 	size_t element_size;
 };
 
+struct dma_ring_buffer_to_periph {
+	void *src_buffer;
+	size_t buffer_count;
+	DMA_Stream_TypeDef *dma;
+	volatile size_t dma_get_idx_current;
+	volatile size_t dma_get_idx_future;
+	volatile size_t sw_put_idx;
+	uint8_t dma_base_id;
+	size_t element_size;
+};
+
 int dma_ring_buffer_periph_to_mem_initialize(struct dma_ring_buffer_to_mem *dma_buffer, uint8_t base_dma_id, DMA_Stream_TypeDef *dma_stream, size_t buffer_element_count, size_t element_size, void *data_buffer, void *src_reg, uint8_t dma_trigger_channel);
 int dma_ring_buffer_periph_to_mem_get_data(struct dma_ring_buffer_to_mem *buff, const void **data_buff, size_t *len);
 void dma_ring_buffer_periph_to_mem_stop(struct dma_ring_buffer_to_mem *buff);
+
+int dma_ring_buffer_mem_to_periph_initialize(struct dma_ring_buffer_to_periph *dma_buffer, uint8_t base_dma_id, DMA_Stream_TypeDef *dma_stream, size_t buffer_element_count, size_t element_size, void *data_buffer, uint8_t dma_trigger_channel, void *dest_reg);
+int dma_ring_buffer_mem_to_periph_insert_data(struct dma_ring_buffer_to_periph *buff, const void *data_to_insert, size_t count);
+void dma_ring_buffer_mem_to_periph_int_callback(struct dma_ring_buffer_to_periph *buff);
+void dma_ring_buffer_mem_to_periph_stop(struct dma_ring_buffer_to_periph *buff);
+
 #endif /* __DMA_RING_BUFFER_H__ */
 
 

stm-firmware/include/uart/uart.h

@@ -6,7 +6,7 @@
 
 #define UART_RECEIVE_DMA_STREAM DMA2_Stream5
 
-#define UART_SEND_DMA_STREAM
+#define UART_SEND_DMA_STREAM DMA2_Stream7
 
 #define UART_PERIPH USART1
 #define UART_RCC_MASK RCC_APB2ENR_USART1EN
@@ -42,11 +42,11 @@ void uart_send_char(char c);
 
 void uart_send_array(const char *data, uint32_t len);
 
-void uart_send_string(char *string);
+void uart_send_string(const char *string);
 
-void uart_send_array_with_dma(char *data, uint32_t len);
+void uart_send_array_with_dma(const char *data, uint32_t len);
 
-void uart_send_string_with_dma(char *string);
+void uart_send_string_with_dma(const char *string);
 
 int uart_receive_data_with_dma(const char **data, size_t *len);
 

stm-firmware/main.c

@@ -57,7 +57,6 @@ int main()
 			shell_handle_input(shell_handle, uart_input, uart_input_len);
 		}
 		//systick_wait_ms(300);
-
 	}
 
 }

stm-firmware/shell.c

@@ -16,8 +16,7 @@ static char history_buffer[1024];
 
 static shellmatta_retCode_t write_shell_callback(const char *data, uint32_t len)
 {
-	uart_send_array(data, len);
+	uart_send_array_with_dma(data, len);
-
 	return SHELLMATTA_OK;
 }
 

stm-firmware/uart/dma-ring-buffer.c

@@ -1,6 +1,7 @@
 #include <uart/dma-ring-buffer.h>
 #include <clock-enable-manager.h>
 #include <stdbool.h>
+#include <string.h>
 
 static int dma_ring_buffer_switch_clock_enable(uint8_t base_dma, bool clk_en)
 {
@@ -105,3 +106,135 @@ void dma_ring_buffer_periph_to_mem_stop(struct dma_ring_buffer_to_mem *buff)
 
 	dma_ring_buffer_switch_clock_enable(buff->base_dma_id, false);
 }
+
+int dma_ring_buffer_mem_to_periph_initialize(struct dma_ring_buffer_to_periph *dma_buffer, uint8_t base_dma_id, DMA_Stream_TypeDef *dma_stream, size_t buffer_element_count, size_t element_size, void *data_buffer, uint8_t dma_trigger_channel, void *dest_reg)
+{
+	if (!dma_buffer || !dma_stream || !data_buffer || !dest_reg)
+		return -1000;
+
+	dma_buffer->dma = dma_stream;
+	dma_buffer->dma_base_id = base_dma_id;
+	dma_buffer->src_buffer = data_buffer;
+	dma_buffer->buffer_count = buffer_element_count;
+	dma_buffer->element_size = element_size;
+	dma_buffer->sw_put_idx = 0U;
+	dma_buffer->dma_get_idx_current = 0U;
+	dma_buffer->dma_get_idx_future = 0U;
+
+	dma_ring_buffer_switch_clock_enable(base_dma_id, true);
+
+	dma_stream->PAR = (uint32_t)dest_reg;
+	dma_stream->CR = DMA_SxCR_MINC | DMA_SxCR_TCIE | (dma_trigger_channel<<25) | DMA_SxCR_DIR_0;
+
+	return 0;
+}
+
+static size_t calculate_ring_buffer_fill_level(size_t buffer_size, size_t get_idx, size_t put_idx)
+{
+	size_t fill_level;
+
+	if (put_idx >= get_idx) {
+		fill_level = (put_idx - get_idx);
+	} else {
+		fill_level = buffer_size - get_idx + put_idx;
+	}
+
+	return fill_level;
+}
+
+static void queue_or_start_dma_transfer(struct dma_ring_buffer_to_periph *buff)
+{
+	uint32_t dma_transfer_cnt;
+
+	if (!buff)
+		return;
+
+	/* Check if DMA is running. Do nothing in this case. Will be stated from interrupt */
+	if (buff->dma_get_idx_current != buff->dma_get_idx_future)
+		return;
+
+	/* No new data to transfer */
+	if (buff->sw_put_idx == buff->dma_get_idx_current)
+		return;
+
+	/* Calculate future get idx. Stop at end of buffer to prevent impossible wrap around */
+	if (buff->sw_put_idx < buff->dma_get_idx_current && buff->sw_put_idx != 0) {
+		buff->dma_get_idx_future = 0U;
+		dma_transfer_cnt = buff->buffer_count - buff->dma_get_idx_current;
+	} else {
+		buff->dma_get_idx_future = buff->sw_put_idx;
+		if (buff->sw_put_idx == 0)
+			dma_transfer_cnt = buff->buffer_count - buff->dma_get_idx_current;
+		else
+			dma_transfer_cnt = buff->sw_put_idx - buff->dma_get_idx_current;
+	}
+
+	buff->dma->NDTR = dma_transfer_cnt;
+	buff->dma->M0AR = (uint32_t)&((char *)buff->src_buffer)[buff->dma_get_idx_current * buff->element_size];
+	buff->dma->CR |= DMA_SxCR_EN;
+}
+
+int dma_ring_buffer_mem_to_periph_insert_data(struct dma_ring_buffer_to_periph *buff, const void *data_to_insert, size_t count)
+{
+	int ret = 0;
+	size_t free_item_count;
+	char *insert_ptr;
+	char *dest_ptr;
+	void *ptr;
+	size_t first_round_count;
+
+	if (!buff || !data_to_insert || !count)
+		return -1000;
+
+	/* Check if data fits into buffer minus one element. If not: try full-1 buffer and rest
+	 * Buffer is not allowed to be completely full, because I cannot ddifferentiate a full buffer from a completely empty one
+	 */
+	if (count >= buff->buffer_count) {
+		ret = dma_ring_buffer_mem_to_periph_insert_data(buff, data_to_insert, buff->buffer_count - 1);
+		if (ret)
+			goto return_retval;
+		ptr = (void *)(((char *)data_to_insert) + ((buff->buffer_count-1) * buff->element_size));
+		ret = dma_ring_buffer_mem_to_periph_insert_data(buff, ptr, count - buff->buffer_count + 1);
+		goto return_retval;
+	}
+
+	/* Wait for buffer to be able to handle input */
+	do {
+		free_item_count = buff->buffer_count - calculate_ring_buffer_fill_level(buff->buffer_count, buff->dma_get_idx_current, buff->sw_put_idx);
+	} while (free_item_count < count+1);
+
+	/* Fillup buffer (max is buffer end, wrap around afterwards) */
+	insert_ptr = (char *)data_to_insert;
+	dest_ptr = &((char *)buff->src_buffer)[buff->sw_put_idx * buff->element_size];
+	if (buff->buffer_count - buff->sw_put_idx >= count) {
+		memcpy(dest_ptr, insert_ptr, buff->element_size * count);
+		buff->sw_put_idx += count;
+		if(buff->sw_put_idx >= buff->buffer_count)
+			buff->sw_put_idx = 0;
+	} else {
+		first_round_count = buff->element_size * (buff->buffer_count - buff->sw_put_idx);
+		memcpy(dest_ptr, insert_ptr, first_round_count);
+		insert_ptr += first_round_count;
+		memcpy(buff->src_buffer, insert_ptr, count - first_round_count);
+		buff->sw_put_idx = count - first_round_count;
+	}
+	queue_or_start_dma_transfer(buff);
+
+return_retval:
+	return ret;
+}
+
+void dma_ring_buffer_mem_to_periph_int_callback(struct dma_ring_buffer_to_periph *buff)
+{
+	/* update current get index */
+	buff->dma_get_idx_current = buff->dma_get_idx_future;
+	queue_or_start_dma_transfer(buff);
+}
+
+void dma_ring_buffer_mem_to_periph_stop(struct dma_ring_buffer_to_periph *buff)
+{
+	buff->dma->CR = 0;
+	dma_ring_buffer_switch_clock_enable(buff->dma_base_id, false);
+
+	memset(buff, 0, sizeof(struct dma_ring_buffer_to_periph));
+}

stm-firmware/uart/uart.c

@@ -13,10 +13,12 @@
 #include <clock-enable-manager.h>
 #include <stm32-gpio-macros.h>
 #include <uart/dma-ring-buffer.h>
+#include <string.h>
 
 static struct dma_ring_buffer_to_mem ring_buff_rx;
+static struct dma_ring_buffer_to_periph ring_buff_tx;
 static char uart_rx_buffer[64];
-
+static char uart_tx_buffer[256];
 
 #ifdef DEBUGBUILD
 static inline void uart_gpio_config()
@@ -41,6 +43,10 @@ void uart_init_with_dma()
 
 	dma_ring_buffer_periph_to_mem_initialize(&ring_buff_rx, 2, UART_RECEIVE_DMA_STREAM, sizeof(uart_rx_buffer), 1U,
 						 uart_rx_buffer, (char *)&UART_PERIPH->DR, 4);
+	dma_ring_buffer_mem_to_periph_initialize(&ring_buff_tx, 2, UART_SEND_DMA_STREAM, sizeof(uart_tx_buffer), 1U,
+						 uart_tx_buffer, 4U, (void *)&UART_PERIPH->DR);
+
+	NVIC_EnableIRQ(DMA2_Stream7_IRQn);
 }
 
 void uart_disable()
@@ -49,7 +55,7 @@ void uart_disable()
 	UART_PERIPH->CR2 = 0;
 	UART_PERIPH->CR3 = 0;
 	dma_ring_buffer_periph_to_mem_stop(&ring_buff_rx);
-
+	dma_ring_buffer_mem_to_periph_stop(&ring_buff_tx);
 	rcc_manager_disable_clock(&RCC->AHB1ENR, BITMASK_TO_BITNO(UART_PORT_RCC_MASK));
 	rcc_manager_disable_clock(&RCC->APB2ENR, BITMASK_TO_BITNO(UART_RCC_MASK));
 }
@@ -68,7 +74,7 @@ void uart_send_array(const char *data, uint32_t len)
 		uart_send_char(data[i]);
 }
 
-void uart_send_string(char *string)
+void uart_send_string(const char *string)
 {
 	int i;
 
@@ -76,11 +82,30 @@ void uart_send_string(char *string)
 		uart_send_char(string[i]);
 }
 
-void uart_send_array_with_dma(char *data, uint32_t len);
+void uart_send_array_with_dma(const char *data, uint32_t len)
+{
+	dma_ring_buffer_mem_to_periph_insert_data(&ring_buff_tx, data, len);
+}
 
-void uart_send_string_with_dma(char *string);
+void uart_send_string_with_dma(const char *string)
+{
+	size_t len;
+
+	len = strlen(string);
+	uart_send_array_with_dma(string, (uint32_t)len);
+}
 
 int uart_receive_data_with_dma(const char **data, size_t *len)
 {
 	return dma_ring_buffer_periph_to_mem_get_data(&ring_buff_rx, (const void **)data, len);
 }
+
+void DMA2_Stream7_IRQHandler()
+{
+	uint32_t hisr = DMA2->HISR;
+	DMA2->HIFCR = hisr;
+
+	if (hisr & DMA_HISR_TCIF7) {
+		dma_ring_buffer_mem_to_periph_int_callback(&ring_buff_tx);
+	}
+}