text: /* ipm_console.c - Console messages to/from another processor */
  
  /*
   * Copyright (c) 2015 Intel Corporation
   *
   * SPDX-License-Identifier: Apache-2.0
   */
  
  #include <errno.h>
  
  #include <zephyr/kernel.h>
  #include <zephyr/sys/ring_buffer.h>
  #include <zephyr/sys/printk.h>
  #include <stdio.h>
  #include <zephyr/drivers/ipm.h>
  #include <zephyr/drivers/console/ipm_console.h>
  #include <zephyr/sys/__assert.h>
  
  static void ipm_console_thread(void *arg1, void *arg2, void *arg3)
  {
  	uint8_t size32;
  	uint16_t type;
  	int ret, key;
  	const struct ipm_console_receiver_config_info *config_info;
  	struct ipm_console_receiver_runtime_data *driver_data;
  	int pos;
  
  	driver_data = (struct ipm_console_receiver_runtime_data *)arg1;
  	config_info = (const struct ipm_console_receiver_config_info *)arg2;
  	ARG_UNUSED(arg3);
  	size32 = 0U;
  	pos = 0;
  
  	while (1) {
  		k_sem_take(&driver_data->sem, K_FOREVER);
  
  		ret = ring_buf_item_get(&driver_data->rb, &type,
  					(uint8_t *)&config_info->line_buf[pos],
  					NULL, &size32);
  		if (ret) {
  			/* Shouldn't ever happen... */
  			printk("ipm console ring buffer error: %d\n", ret);
  			size32 = 0U;
  			continue;
  		}
  
  		if (config_info->line_buf[pos] == '\n' ||
  		    pos == config_info->lb_size - 2) {
  			if (pos != config_info->lb_size - 2) {
  				config_info->line_buf[pos] = '\0';
  			} else {
  				config_info->line_buf[pos + 1] = '\0';
  			}
  			if (config_info->flags & IPM_CONSOLE_PRINTK) {
  				printk("ipm_console: '%s'\n",
  				       config_info->line_buf);
  			}
  			if (config_info->flags & IPM_CONSOLE_STDOUT) {
  				printf("ipm_console: '%s'\n",
  				       config_info->line_buf);
  			}
  			pos = 0;
  		} else {
  			++pos;
  		}
  
  		/* ISR may have disabled the channel due to full buffer at
  		 * some point. If that happened and there is now room,
  		 * re-enable it.
  		 *
  		 * Lock interrupts to avoid pathological scenario where
  		 * the buffer fills up in between enabling the channel and
  		 * clearing the channel_disabled flag.
  		 */
  		if (driver_data->channel_disabled &&
  		    ring_buf_item_space_get(&driver_data->rb)) {
  			key = irq_lock();
  			ipm_set_enabled(driver_data->ipm_device, 1);
  			driver_data->channel_disabled = 0;
  			irq_unlock(key);
  		}
  	}
  }
  
  static void ipm_console_receive_callback(const struct device *ipm_dev,
  					 void *user_data,
  					 uint32_t id, volatile void *data)
  {
  	struct ipm_console_receiver_runtime_data *driver_data = user_data;
  	int ret;
  
  	ARG_UNUSED(data);
  
  	/* Should always be at least one free buffer slot */
  	ret = ring_buf_item_put(&driver_data->rb, 0, id, NULL, 0);
  	__ASSERT(ret == 0, "Failed to insert data into ring buffer");
  	k_sem_give(&driver_data->sem);
  
  	/* If the buffer is now full, disable future interrupts for this channel
  	 * until the thread has a chance to consume characters.
  	 *
  	 * This works without losing data if the sending side tries to send
  	 * more characters because the sending side is making an ipm_send()
  	 * call with the wait flag enabled.  It blocks until the receiver side
  	 * re-enables the channel and consumes the data.
  	 */
  	if (ring_buf_item_space_get(&driver_data->rb) == 0) {
  		ipm_set_enabled(ipm_dev, 0);
  		driver_data->channel_disabled = 1;
  	}
  }
  
  
  int ipm_console_receiver_init(const struct device *d)
  {
  	const struct ipm_console_receiver_config_info *config_info =
  		d->config;
  	struct ipm_console_receiver_runtime_data *driver_data = d->data;
  	const struct device *ipm;
  
  	ipm = device_get_binding(config_info->bind_to);
  
  	if (!ipm) {
  		printk("unable to bind IPM console receiver to '%s'\n",
  		       config_info->bind_to);
  		return -EINVAL;
  	}
  
  	if (ipm_max_id_val_get(ipm) < 0xFF) {
  		printk("IPM driver %s doesn't support 8-bit id values",
  		       config_info->bind_to);
  		return -EINVAL;
  	}
  
  	driver_data->ipm_device = ipm;
  	driver_data->channel_disabled = 0;
  	k_sem_init(&driver_data->sem, 0, K_SEM_MAX_LIMIT);
  	ring_buf_item_init(&driver_data->rb, config_info->rb_size32,
  			   config_info->ring_buf_data);
  
  	ipm_register_callback(ipm, ipm_console_receive_callback, driver_data);
  
  	k_thread_create(&driver_data->rx_thread, config_info->thread_stack,
  			CONFIG_IPM_CONSOLE_STACK_SIZE, ipm_console_thread,
  			driver_data, (void *)config_info, NULL,
  			K_PRIO_COOP(IPM_CONSOLE_PRI), 0, K_NO_WAIT);
  	ipm_set_enabled(ipm, 1);
  
  	return 0;
  }
  