drivers: spi: cc23x0: Add support for DMA mode

Two DMA channels are assigned to TX and RX respectively:
- A TX DMA single request is asserted when there is space in the FIFO.
- A RX DMA single request is asserted when data is in the FIFO.

Signed-off-by: Julien Panis <jpanis@baylibre.com>

drivers/spi/Kconfig.cc23x0

@@ -10,3 +10,12 @@ config SPI_CC23X0
 	select PINCTRL
 	help
 	  Enable support for the TI SimpleLink CC23x0 SPI peripheral
+
+config SPI_CC23X0_DMA_DRIVEN
+	bool "DMA support for TI CC23X0 SPI devices"
+	depends on SPI_CC23X0
+	select DMA
+	help
+	  DMA driven transactions for the SPI.
+	  DMA driven mode offloads data transfer tasks from the CPU
+	  and requires fewer interrupts to handle the SPI transfers.

drivers/spi/spi_cc23x0.c

@@ -10,6 +10,7 @@
 LOG_MODULE_REGISTER(spi_cc23x0, CONFIG_SPI_LOG_LEVEL);
 
 #include <zephyr/device.h>
+#include <zephyr/drivers/dma.h>
 #include <zephyr/drivers/pinctrl.h>
 #include <zephyr/drivers/spi.h>
 #include <zephyr/irq.h>
@@ -18,6 +19,8 @@ LOG_MODULE_REGISTER(spi_cc23x0, CONFIG_SPI_LOG_LEVEL);
 #include <driverlib/clkctl.h>
 #include <driverlib/spi.h>
 
+#include <inc/hw_memmap.h>
+
 #include "spi_context.h"
 
 /*
@@ -30,20 +33,34 @@ LOG_MODULE_REGISTER(spi_cc23x0, CONFIG_SPI_LOG_LEVEL);
 #define SPI_CC23_DATA_WIDTH	8
 #define SPI_CC23_DFS		(SPI_CC23_DATA_WIDTH >> 3)
 
+#ifdef CONFIG_SPI_CC23X0_DMA_DRIVEN
+#define SPI_CC23_REG_GET(base, offset) ((base) + (offset))
+#define SPI_CC23_INT_MASK	SPI_DMA_DONE_RX
+#else
 #define SPI_CC23_INT_MASK	(SPI_TXEMPTY | SPI_IDLE | SPI_RX)
+#endif
 
 struct spi_cc23x0_config {
 	uint32_t base;
 	const struct pinctrl_dev_config *pincfg;
 	void (*irq_config_func)(void);
+#ifdef CONFIG_SPI_CC23X0_DMA_DRIVEN
+	const struct device *dma_dev;
+	uint8_t dma_channel_tx;
+	uint8_t dma_trigsrc_tx;
+	uint8_t dma_channel_rx;
+	uint8_t dma_trigsrc_rx;
+#endif
 };
 
 struct spi_cc23x0_data {
 	struct spi_context ctx;
 	size_t tx_len_left;
+#ifndef CONFIG_SPI_CC23X0_DMA_DRIVEN
 	uint32_t tx_count;
 	uint32_t rx_count;
 	bool xfer_done;
+#endif
 };
 
 static void spi_cc23x0_isr(const struct device *dev)
@@ -51,12 +68,20 @@ static void spi_cc23x0_isr(const struct device *dev)
 	const struct spi_cc23x0_config *cfg = dev->config;
 	struct spi_cc23x0_data *data = dev->data;
 	struct spi_context *ctx = &data->ctx;
-	uint32_t txd = 0, rxd;
 	uint32_t status;
+#ifndef CONFIG_SPI_CC23X0_DMA_DRIVEN
+	uint32_t txd = 0, rxd;
+#endif
 
 	status = SPIIntStatus(cfg->base, true);
 	LOG_DBG("status = %08x", status);
 
+#ifdef CONFIG_SPI_CC23X0_DMA_DRIVEN
+	if (status & SPI_DMA_DONE_RX) {
+		SPIClearInt(cfg->base, SPI_DMA_DONE_RX);
+		spi_context_complete(ctx, dev, 0);
+	}
+#else
 	/*
 	 * Disabling the interrupts in this ISR when SPI has completed
 	 * the transfer triggers a subsequent spurious interrupt, with
@@ -124,6 +149,7 @@ static void spi_cc23x0_isr(const struct device *dev)
 		SPIDisableInt(cfg->base, SPI_CC23_INT_MASK);
 		spi_context_complete(ctx, dev, 0);
 	}
+#endif
 }
 
 static int spi_cc23x0_configure(const struct device *dev,
@@ -221,9 +247,11 @@ static void spi_cc23x0_initialize_data(struct spi_cc23x0_data *data)
 {
 	data->tx_len_left = MAX(spi_context_total_tx_len(&data->ctx),
 				spi_context_total_rx_len(&data->ctx));
+#ifndef CONFIG_SPI_CC23X0_DMA_DRIVEN
 	data->tx_count = 0;
 	data->rx_count = 0;
 	data->xfer_done = false;
+#endif
 }
 
 static int spi_cc23x0_transceive(const struct device *dev,
@@ -235,6 +263,43 @@ static int spi_cc23x0_transceive(const struct device *dev,
 	struct spi_cc23x0_data *data = dev->data;
 	struct spi_context *ctx = &data->ctx;
 	int ret;
+#ifdef CONFIG_SPI_CC23X0_DMA_DRIVEN
+	struct dma_block_config block_cfg_tx = {
+		.dest_address = SPI_CC23_REG_GET(cfg->base, SPI_O_TXDATA),
+		.dest_addr_adj = DMA_ADDR_ADJ_NO_CHANGE,
+		.block_size = 1,
+	};
+
+	struct dma_config dma_cfg_tx = {
+		.dma_slot = cfg->dma_trigsrc_tx,
+		.channel_direction = MEMORY_TO_PERIPHERAL,
+		.block_count = 1,
+		.head_block = &block_cfg_tx,
+		.source_data_size = SPI_CC23_DFS,
+		.dest_data_size = SPI_CC23_DFS,
+		.source_burst_length = SPI_CC23_DFS,
+		.dma_callback = NULL,
+		.user_data = NULL,
+	};
+
+	struct dma_block_config block_cfg_rx = {
+		.source_address = SPI_CC23_REG_GET(cfg->base, SPI_O_RXDATA),
+		.source_addr_adj = DMA_ADDR_ADJ_NO_CHANGE,
+		.block_size = 1,
+	};
+
+	struct dma_config dma_cfg_rx = {
+		.dma_slot = cfg->dma_trigsrc_rx,
+		.channel_direction = PERIPHERAL_TO_MEMORY,
+		.block_count = 1,
+		.head_block = &block_cfg_rx,
+		.source_data_size = SPI_CC23_DFS,
+		.dest_data_size = SPI_CC23_DFS,
+		.source_burst_length = SPI_CC23_DFS,
+		.dma_callback = NULL,
+		.user_data = NULL,
+	};
+#endif
 
 	spi_context_lock(ctx, false, NULL, NULL, config);
 
@@ -245,12 +310,65 @@ static int spi_cc23x0_transceive(const struct device *dev,
 
 	spi_context_buffers_setup(ctx, tx_bufs, rx_bufs, SPI_CC23_DFS);
 
+#ifdef CONFIG_SPI_CC23X0_DMA_DRIVEN
+	if (spi_context_total_tx_len(ctx) != spi_context_total_rx_len(ctx)) {
+		LOG_ERR("In DMA mode, RX and TX buffer lengths must be the same");
+		ret = -EINVAL;
+		goto ctx_release;
+	}
+#endif
+
 	spi_cc23x0_initialize_data(data);
 
 	spi_context_cs_control(ctx, true);
 
 	SPIEnableInt(cfg->base, SPI_CC23_INT_MASK);
 
+#ifdef CONFIG_SPI_CC23X0_DMA_DRIVEN
+	block_cfg_tx.source_address = (uint32_t)ctx->tx_buf;
+	block_cfg_tx.source_addr_adj = DMA_ADDR_ADJ_INCREMENT;
+	block_cfg_tx.block_size = SPI_CC23_DFS * data->tx_len_left;
+
+	block_cfg_rx.dest_address = (uint32_t)ctx->rx_buf;
+	block_cfg_rx.dest_addr_adj = DMA_ADDR_ADJ_INCREMENT;
+	block_cfg_rx.block_size = SPI_CC23_DFS * data->tx_len_left;
+
+	ret = dma_config(cfg->dma_dev, cfg->dma_channel_tx, &dma_cfg_tx);
+	if (ret) {
+		LOG_ERR("Failed to configure DMA TX channel");
+		goto int_disable;
+	}
+
+	ret = dma_config(cfg->dma_dev, cfg->dma_channel_rx, &dma_cfg_rx);
+	if (ret) {
+		LOG_ERR("Failed to configure DMA RX channel");
+		goto int_disable;
+	}
+
+	/* Disable DMA triggers */
+	SPIDisableDMA(cfg->base, SPI_DMA_TX | SPI_DMA_RX);
+
+	/* Start DMA channels */
+	dma_start(cfg->dma_dev, cfg->dma_channel_rx);
+	dma_start(cfg->dma_dev, cfg->dma_channel_tx);
+
+	/* Enable DMA triggers to start transfer */
+	SPIEnableDMA(cfg->base, SPI_DMA_TX | SPI_DMA_RX);
+
+	ret = spi_context_wait_for_completion(&data->ctx);
+	if (ret) {
+		LOG_ERR("SPI transfer failed (%d)", ret);
+		goto int_disable;
+	}
+
+	spi_context_update_tx(ctx, SPI_CC23_DFS, data->tx_len_left);
+	spi_context_update_rx(ctx, SPI_CC23_DFS, data->tx_len_left);
+
+	LOG_DBG("SPI transfer completed");
+
+int_disable:
+	SPIDisableInt(cfg->base, SPI_CC23_INT_MASK);
+#else
 	ret = spi_context_wait_for_completion(ctx);
 	if (ret) {
 		SPIDisableInt(cfg->base, SPI_CC23_INT_MASK);
@@ -258,6 +376,7 @@ static int spi_cc23x0_transceive(const struct device *dev,
 	} else {
 		LOG_DBG("SPI transfer completed");
 	}
+#endif
 
 	spi_context_cs_control(ctx, false);
 
@@ -304,6 +423,13 @@ static int spi_cc23x0_init(const struct device *dev)
 		return ret;
 	}
 
+#ifdef CONFIG_SPI_CC23X0_DMA_DRIVEN
+	if (!device_is_ready(cfg->dma_dev)) {
+		LOG_ERR("DMA not ready");
+		return -ENODEV;
+	}
+#endif
+
 	ret = spi_context_cs_configure_all(&data->ctx);
 	if (ret) {
 		return ret;
@@ -314,6 +440,17 @@ static int spi_cc23x0_init(const struct device *dev)
 	return 0;
 }
 
+#ifdef CONFIG_SPI_CC23X0_DMA_DRIVEN
+#define SPI_CC23X0_DMA_INIT(n)						\
+	.dma_dev = DEVICE_DT_GET(TI_CC23X0_DT_INST_DMA_CTLR(n, tx)),	\
+	.dma_channel_tx = TI_CC23X0_DT_INST_DMA_CHANNEL(n, tx),		\
+	.dma_trigsrc_tx = TI_CC23X0_DT_INST_DMA_TRIGSRC(n, tx),		\
+	.dma_channel_rx = TI_CC23X0_DT_INST_DMA_CHANNEL(n, rx),		\
+	.dma_trigsrc_rx = TI_CC23X0_DT_INST_DMA_TRIGSRC(n, rx),
+#else
+#define SPI_CC23X0_DMA_INIT(n)
+#endif
+
 #define SPI_CC23X0_INIT(n)						\
 	PINCTRL_DT_INST_DEFINE(n);					\
 									\
@@ -329,7 +466,8 @@ static int spi_cc23x0_init(const struct device *dev)
 	static const struct spi_cc23x0_config spi_cc23x0_config_##n = {	\
 		.base = DT_INST_REG_ADDR(n),				\
 		.pincfg = PINCTRL_DT_INST_DEV_CONFIG_GET(n),		\
-		.irq_config_func = spi_irq_config_func_##n		\
+		.irq_config_func = spi_irq_config_func_##n,		\
+		SPI_CC23X0_DMA_INIT(n)					\
 	};								\
 									\
 	static struct spi_cc23x0_data spi_cc23x0_data_##n = {		\

dts/bindings/spi/ti,cc23x0-spi.yaml

@@ -19,3 +19,20 @@ properties:
 
   pinctrl-names:
     required: true
+
+  dmas:
+    description: |
+      Optional TX & RX DMA specifiers. Each specifier will have a phandle
+      reference to the DMA controller, the channel number, and the peripheral
+      trigger source.
+
+      Example for channels 0/1 with spi0txtrg/spi0rxtrg trigger sources:
+        dmas = <&dma 0 0>, <&dma 1 1>;
+
+  dma-names:
+    description: |
+      Required if the dmas property exists. This should be "tx" and "rx"
+      to match the dmas property.
+
+      Example:
+        dma-names = "tx", "rx";