sdp: egpio: backends functionality improvements

Add MBOX improvements to ensuring that data has been read
by the remote core.
Add general structure code improvements to header files.

Signed-off-by: Jakub Zymelka <jakub.zymelka@nordicsemi.no>

Author: jaz1-nordic

applications/sdp/gpio/src/backend/backend.h

@@ -9,9 +9,9 @@
 
 #include <drivers/gpio/nrfe_gpio.h>
 
-#if !defined(CONFIG_GPIO_NRFE_EGPIO_BACKEND_ICMSG) && \
-	!defined(CONFIG_GPIO_NRFE_EGPIO_BACKEND_MBOX) && \
-	!defined(CONFIG_GPIO_NRFE_EGPIO_BACKEND_ICBMSG)
+#if !IS_ENABLED(CONFIG_GPIO_NRFE_EGPIO_BACKEND_ICMSG) && \
+	!IS_ENABLED(CONFIG_GPIO_NRFE_EGPIO_BACKEND_MBOX) && \
+	!IS_ENABLED(CONFIG_GPIO_NRFE_EGPIO_BACKEND_ICBMSG)
 #error "Define communication backend type"
 #endif
 

applications/sdp/gpio/src/backend/backend_mbox.c

@@ -34,8 +34,9 @@ static void mbox_callback(const struct device *instance, uint32_t channel, void
 	nrfe_gpio_mbox_data_t *rx_data = (nrfe_gpio_mbox_data_t *)user_data;
 
 	/* Try and get lock for the shared data structure */
-	if (atomic_flag_test_and_set(&rx_data->lock.locked)) {
-		/* Return in case lock is not acquired (used by other core)*/
+	if (!atomic_cas(&rx_data->lock.locked, DATA_LOCK_STATE_WITH_DATA, DATA_LOCK_STATE_BUSY)) {
+		/* Return in case buffer is without data */
+		atomic_set(&rx_data->lock.locked, DATA_LOCK_STATE_READY);
 		return;
 	}
 
@@ -49,7 +50,7 @@ static void mbox_callback(const struct device *instance, uint32_t channel, void
 	rx_data->lock.data_size = 0;
 
 	/* We are finished with the shared data structure, so we can release the lock */
-	atomic_flag_clear(&rx_data->lock.locked);
+	atomic_set(&rx_data->lock.locked, DATA_LOCK_STATE_READY);
 }
 
 /**
@@ -88,8 +89,8 @@ int backend_init(backend_callback_t callback)
 	}
 
 	/* clear the buffer locks and their size holders */
-	atomic_flag_clear(&rx_data->lock.locked);
 	rx_data->lock.data_size = 0;
+	atomic_set(&rx_data->lock.locked, DATA_LOCK_STATE_READY);
 
 	return 0;
 }

drivers/gpio/gpio_nrfe_icmsg.c

@@ -11,7 +11,7 @@
 #include "gpio_nrfe.h"
 
 #if defined(CONFIG_MULTITHREADING)
-K_SEM_DEFINE(bound_sem, 0, 1);
+static K_SEM_DEFINE(bound_sem, 0, 1);
 #else
 static volatile uint32_t bound_sem = 1;
 #endif

drivers/gpio/gpio_nrfe_mbox.c

@@ -7,7 +7,6 @@
 #include <zephyr/drivers/gpio.h>
 #include <zephyr/drivers/gpio/gpio_utils.h>
 #include <zephyr/drivers/mbox.h>
-#include <zephyr/sys/printk.h>
 
 #include "gpio_nrfe.h"
 
@@ -18,19 +17,15 @@ static nrfe_gpio_mbox_data_t *tx_data =
 
 int gpio_send(nrfe_gpio_data_packet_t *msg)
 {
-	printk("Sending opcode: %d, pin %d, port %d, flag: %d\n", msg->opcode, msg->pin, msg->port,
-	       msg->flags);
-	/* Try and get lock */
-	if (atomic_flag_test_and_set(&tx_data->lock.locked)) {
-		/* Return -1 in case lock is not acquired (used by other core)*/
-		return -1;
+	/* Wait for the access to the shared data structure */
+	while (!atomic_cas(&tx_data->lock.locked, DATA_LOCK_STATE_READY, DATA_LOCK_STATE_BUSY)) {
 	}
 
 	memcpy((void *)&tx_data->data, (void *)msg, sizeof(nrfe_gpio_data_packet_t));
 	tx_data->lock.data_size = sizeof(nrfe_gpio_data_packet_t);
 
-	/* Release lock */
-	atomic_flag_clear(&tx_data->lock.locked);
+	/* Inform the consumer that new data is available */
+	atomic_set(&tx_data->lock.locked, DATA_LOCK_STATE_WITH_DATA);
 
 	return mbox_send_dt(&tx_channel, NULL);
 }

include/drivers/gpio/nrfe_gpio.h

@@ -33,8 +33,8 @@ typedef struct __packed {
 			 */
 } nrfe_gpio_data_packet_t;
 
-typedef struct __packed {
-	nrfe_shared_data_lock_t lock;
+typedef struct {
+	struct nrfe_shared_data_lock lock;
 	nrfe_gpio_data_packet_t data;
 } nrfe_gpio_mbox_data_t;
 

include/sdp/nrfe_common.h

@@ -4,22 +4,29 @@
  * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
  */
 
-#ifndef NRFE_COMMON_H__
-#define NRFE_COMMON_H__
+#ifndef SDP_NRFE_COMMON_H__
+#define SDP_NRFE_COMMON_H__
 
-#include <stdatomic.h>
+#include <zephyr/sys/atomic.h>
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
-typedef struct __packed {
-	atomic_bool locked;
+enum data_lock_state {
+	DATA_LOCK_STATE_OFF = 0,
+	DATA_LOCK_STATE_BUSY,
+	DATA_LOCK_STATE_WITH_DATA,
+	DATA_LOCK_STATE_READY,
+};
+
+struct nrfe_shared_data_lock {
 	uint32_t data_size;
-} nrfe_shared_data_lock_t;
+	atomic_t locked;
+};
 
 #ifdef __cplusplus
 }
 #endif
 
-#endif /* NRFE_COMMON_H__ */
+#endif /* SDP_NRFE_COMMON_H__ */