drivers/dma: stm32: Preparation for QSPI DMA mode support

In preparation for QSPI DMA mode:
-Add a possibility to override driver by the HAL DMA. In that case
stream is set as busy and no configuration nor treatment is done.
In case of interrupt, flags clearing is let to HAL.
-Treat Half Transfer interrupt prior to Transfer Complete for the
cases were both IRQ are both raised at the time IRQ handler is called

Signed-off-by: Erwan Gouriou <[email protected]>

Author: erwango

drivers/dma/dma_stm32.c

@@ -15,6 +15,7 @@
 
 #include <init.h>
 #include <drivers/clock_control.h>
+#include <drivers/dma/dma_stm32.h>
 
 #include <logging/log.h>
 LOG_MODULE_REGISTER(dma_stm32, CONFIG_DMA_LOG_LEVEL);
@@ -101,14 +102,21 @@ static void dma_stm32_irq_handler(const struct device *dev, uint32_t id)
 	}
 
 	/* the dma stream id is in range from STREAM_OFFSET..<dma-requests> */
-	if (dma_stm32_is_tc_active(dma, id)) {
-		dma_stm32_clear_tc(dma, id);
+	if (dma_stm32_is_ht_active(dma, id)) {
+		/* Let HAL DMA handle flags on its own */
+		if (!stream->hal_override) {
+			dma_stm32_clear_ht(dma, id);
+		}
+		stream->dma_callback(dev, stream->user_data, callback_arg, 0);
+	} else if (dma_stm32_is_tc_active(dma, id)) {
 #ifdef CONFIG_DMAMUX_STM32
 		stream->busy = false;
 #endif
+		/* Let HAL DMA handle flags on its own */
+		if (!stream->hal_override) {
+			dma_stm32_clear_tc(dma, id);
+		}
 		stream->dma_callback(dev, stream->user_data, callback_arg, 0);
-	} else if (dma_stm32_is_ht_active(dma, id)) {
-		dma_stm32_clear_ht(dma, id);
 	} else if (stm32_dma_is_unexpected_irq_happened(dma, id)) {
 		LOG_ERR("Unexpected irq happened.");
 		stream->dma_callback(dev, stream->user_data,
@@ -255,6 +263,19 @@ DMA_STM32_EXPORT_API int dma_stm32_configure(const struct device *dev,
 	/* give channel from index 0 */
 	id = id - STREAM_OFFSET;
 
+	/* Check potential DMA override */
+	if (config->linked_channel == STM32_DMA_HAL_OVERRIDE) {
+		/* DMA channel is overridden by HAL DMA
+		 * Retain that the channel is busy and proceed to the minimal
+		 * configuration to properly route the IRQ
+		 */
+		stream->busy = true;
+		stream->hal_override = true;
+		stream->dma_callback = config->dma_callback;
+		stream->user_data = config->user_data;
+		return 0;
+	}
+
 	if (id >= dev_config->max_streams) {
 		LOG_ERR("cannot configure the dma stream %d.", id);
 		return -EINVAL;

drivers/dma/dma_stm32.h

@@ -21,6 +21,7 @@ struct dma_stm32_stream {
 	int mux_channel; /* stores the dmamux channel */
 #endif /* CONFIG_DMAMUX_STM32 */
 	bool source_periph;
+	bool hal_override;
 	volatile bool busy;
 	uint32_t src_size;
 	uint32_t dst_size;

include/drivers/dma/dma_stm32.h

@@ -0,0 +1,15 @@
+/*
+ * Copyright (c) 2021 Linaro Limited
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef ZEPHYR_INCLUDE_DRIVERS_DMA_STM32_H_
+#define ZEPHYR_INCLUDE_DRIVERS_DMA_STM32_H_
+
+/* @brief linked_channel value to inform zephyr dma driver that
+ * DMA channel will be handled by HAL
+ */
+#define STM32_DMA_HAL_OVERRIDE      0x7F
+
+#endif /* ZEPHYR_INCLUDE_DRIVERS_DMA_STM32_H_ */