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/*
* Google LWIS I2C Bus Manager
*
* Copyright (c) 2023 Google, LLC
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#define pr_fmt(fmt) KBUILD_MODNAME "-i2c-sched: " fmt
#include "lwis_i2c_sched.h"
#include "lwis_i2c_bus_manager.h"
/*
* lwis_i2c_process_request_queue_is_empty:
* Checks if the I2C process request queue is empty
*/
static bool lwis_i2c_process_request_queue_is_empty(struct lwis_i2c_process_queue *process_queue)
{
if ((!process_queue) || ((process_queue) && (process_queue->number_of_requests == 0))) {
return true;
}
return false;
}
/*
* lwis_i2c_process_request_queue_initialize:
* Initializes the I2C process request queue for a given I2C Bus
*/
void lwis_i2c_process_request_queue_initialize(struct lwis_i2c_process_queue *process_queue)
{
process_queue->number_of_requests = 0;
INIT_LIST_HEAD(&process_queue->head);
}
/*
* lwis_i2c_process_request_queue_destroy:
* Frees all the requests in the queue
*/
void lwis_i2c_process_request_queue_destroy(struct lwis_i2c_process_queue *process_queue)
{
struct list_head *request;
struct list_head *request_tmp;
struct lwis_i2c_process_request *process_request;
if (!process_queue)
return;
if (lwis_i2c_process_request_queue_is_empty(process_queue))
return;
list_for_each_safe (request, request_tmp, &process_queue->head) {
process_request =
list_entry(request, struct lwis_i2c_process_request, request_node);
list_del(&process_request->request_node);
process_request->requesting_device = NULL;
kfree(process_request);
process_request = NULL;
--process_queue->number_of_requests;
}
}
/*
* lwis_i2c_process_request_queue_enqueue_request:
* Enqueues a requesting device on tail of the I2C Scheduler
*/
int lwis_i2c_process_request_queue_enqueue_request(struct lwis_i2c_process_queue *process_queue,
struct lwis_device **requesting_device)
{
int ret = 0;
struct lwis_i2c_process_request *request;
struct lwis_device *lwis_dev = *requesting_device;
if ((!process_queue) || (!requesting_device) || (!lwis_dev)) {
pr_err("Invalid pointer\n");
return -EINVAL;
}
// Atomic allocation needed here since this memory is allocated within
// transition and periodic io locks of various I2C devices
request = kzalloc(sizeof(struct lwis_i2c_process_request), GFP_ATOMIC);
if (!request) {
dev_err(lwis_dev->dev, "Failed to allocate I2C Process Request Node memory\n");
return -ENOMEM;
}
request->requesting_device = requesting_device;
INIT_LIST_HEAD(&request->request_node);
list_add_tail(&request->request_node, &process_queue->head);
process_queue->number_of_requests++;
return ret;
}
/*
* lwis_i2c_process_request_queue_dequeue_request:
* Dequeues a lwis device from head of the I2C Scheduler
*/
struct lwis_device **
lwis_i2c_process_request_queue_dequeue_request(struct lwis_i2c_process_queue *process_queue)
{
struct lwis_i2c_process_request *request;
struct lwis_device **requested_device = NULL;
if (lwis_i2c_process_request_queue_is_empty(process_queue)) {
return requested_device;
}
request = list_first_entry_or_null(&process_queue->head, struct lwis_i2c_process_request,
request_node);
if (request) {
requested_device = request->requesting_device;
list_del(&request->request_node);
kfree(request);
request = NULL;
process_queue->number_of_requests--;
}
return requested_device;
}
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