| /* |
| * Greybus "AP" message loop handling |
| * |
| * Copyright 2014 Google Inc. |
| * |
| * Released under the GPLv2 only. |
| */ |
| |
| #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| |
| #include <linux/types.h> |
| #include <linux/module.h> |
| #include <linux/moduleparam.h> |
| #include <linux/kernel.h> |
| #include <linux/slab.h> |
| #include <linux/uaccess.h> |
| #include <linux/kthread.h> |
| #include <linux/device.h> |
| #include "greybus.h" |
| |
| /* |
| * AP <-> SVC message structure format: |
| * |
| * |
| * |
| */ |
| struct svc_msg { |
| u8 function; |
| u8 type; |
| u8 version_major; |
| u8 version_minor; |
| u16 payload_length; |
| }; |
| |
| |
| struct ap_msg { |
| u8 *data; |
| int size; |
| struct list_head list; |
| }; |
| |
| static LIST_HEAD(ap_msg_list); |
| static spinlock_t ap_msg_list_lock; |
| static struct task_struct *ap_thread; |
| static wait_queue_head_t ap_wait; |
| |
| static struct ap_msg *get_ap_msg(void) |
| { |
| struct ap_msg *ap_msg; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&ap_msg_list_lock, flags); |
| |
| ap_msg = list_first_entry_or_null(&ap_msg_list, struct ap_msg, list); |
| if (ap_msg != NULL) |
| list_del(&ap_msg->list); |
| spin_unlock_irqrestore(&ap_msg_list_lock, flags); |
| |
| return ap_msg; |
| } |
| |
| static int ap_process_loop(void *data) |
| { |
| struct ap_msg *ap_msg; |
| |
| while (!kthread_should_stop()) { |
| wait_event_interruptible(ap_wait, kthread_should_stop()); |
| |
| if (kthread_should_stop()) |
| break; |
| |
| /* Get some data off of the ap list and process it */ |
| ap_msg = get_ap_msg(); |
| if (!ap_msg) |
| continue; |
| |
| // FIXME - process the message |
| |
| /* clean the message up */ |
| kfree(ap_msg->data); |
| kfree(ap_msg); |
| } |
| return 0; |
| } |
| |
| int gb_new_ap_msg(u8 *data, int size) |
| { |
| struct ap_msg *ap_msg; |
| unsigned long flags; |
| |
| /* |
| * Totally naive copy the message into a new structure that we slowly |
| * create and add it to the list. Let's get this working, the odds of |
| * this being any "slow path" for AP messages is really low at this |
| * point in time, but you never know, so this comment is here to point |
| * out that maybe we should use a slab allocator, or even just not copy |
| * the data, but use it directly and force the urbs to be "new" each |
| * time. |
| */ |
| |
| /* Note - this can, and will, be called in interrupt context. */ |
| ap_msg = kmalloc(sizeof(*ap_msg), GFP_ATOMIC); |
| if (!ap_msg) |
| return -ENOMEM; |
| ap_msg->data = kmalloc(size, GFP_ATOMIC); |
| if (!ap_msg->data) { |
| kfree(ap_msg); |
| return -ENOMEM; |
| } |
| memcpy(ap_msg->data, data, size); |
| ap_msg->size = size; |
| |
| spin_lock_irqsave(&ap_msg_list_lock, flags); |
| list_add(&ap_msg->list, &ap_msg_list); |
| spin_unlock_irqrestore(&ap_msg_list_lock, flags); |
| |
| /* kick our thread to handle the message */ |
| wake_up_interruptible(&ap_wait); |
| |
| return 0; |
| } |
| |
| int gb_thread_init(void) |
| { |
| init_waitqueue_head(&ap_wait); |
| spin_lock_init(&ap_msg_list_lock); |
| |
| ap_thread = kthread_run(ap_process_loop, NULL, "greybus_ap"); |
| if (IS_ERR(ap_thread)) |
| return PTR_ERR(ap_thread); |
| |
| return 0; |
| } |
| |
| void gb_thread_destroy(void) |
| { |
| kthread_stop(ap_thread); |
| } |
| |
| |