Greg Kroah-Hartman | de536e3 | 2014-08-31 16:17:04 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Greybus "AP" message loop handling |
| 3 | * |
| 4 | * Copyright 2014 Google Inc. |
| 5 | * |
| 6 | * Released under the GPLv2 only. |
| 7 | */ |
| 8 | |
| 9 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| 10 | |
| 11 | #include <linux/types.h> |
| 12 | #include <linux/module.h> |
| 13 | #include <linux/moduleparam.h> |
| 14 | #include <linux/kernel.h> |
| 15 | #include <linux/slab.h> |
| 16 | #include <linux/uaccess.h> |
| 17 | #include <linux/kthread.h> |
| 18 | #include <linux/device.h> |
Greg Kroah-Hartman | b9b2a46 | 2014-08-31 17:43:38 -0700 | [diff] [blame] | 19 | #include "svc_msg.h" |
Greg Kroah-Hartman | 80ebe8a | 2014-08-31 18:08:52 -0700 | [diff] [blame] | 20 | #include "greybus_desc.h" |
Greg Kroah-Hartman | de536e3 | 2014-08-31 16:17:04 -0700 | [diff] [blame] | 21 | #include "greybus.h" |
| 22 | |
Greg Kroah-Hartman | de536e3 | 2014-08-31 16:17:04 -0700 | [diff] [blame] | 23 | struct ap_msg { |
| 24 | u8 *data; |
| 25 | int size; |
| 26 | struct list_head list; |
| 27 | }; |
| 28 | |
| 29 | static LIST_HEAD(ap_msg_list); |
| 30 | static spinlock_t ap_msg_list_lock; |
| 31 | static struct task_struct *ap_thread; |
| 32 | static wait_queue_head_t ap_wait; |
| 33 | |
| 34 | static struct ap_msg *get_ap_msg(void) |
| 35 | { |
| 36 | struct ap_msg *ap_msg; |
| 37 | unsigned long flags; |
| 38 | |
| 39 | spin_lock_irqsave(&ap_msg_list_lock, flags); |
| 40 | |
| 41 | ap_msg = list_first_entry_or_null(&ap_msg_list, struct ap_msg, list); |
| 42 | if (ap_msg != NULL) |
| 43 | list_del(&ap_msg->list); |
| 44 | spin_unlock_irqrestore(&ap_msg_list_lock, flags); |
| 45 | |
| 46 | return ap_msg; |
| 47 | } |
| 48 | |
| 49 | static int ap_process_loop(void *data) |
| 50 | { |
| 51 | struct ap_msg *ap_msg; |
| 52 | |
| 53 | while (!kthread_should_stop()) { |
| 54 | wait_event_interruptible(ap_wait, kthread_should_stop()); |
| 55 | |
| 56 | if (kthread_should_stop()) |
| 57 | break; |
| 58 | |
| 59 | /* Get some data off of the ap list and process it */ |
| 60 | ap_msg = get_ap_msg(); |
| 61 | if (!ap_msg) |
| 62 | continue; |
| 63 | |
| 64 | // FIXME - process the message |
| 65 | |
| 66 | /* clean the message up */ |
| 67 | kfree(ap_msg->data); |
| 68 | kfree(ap_msg); |
| 69 | } |
| 70 | return 0; |
| 71 | } |
| 72 | |
| 73 | int gb_new_ap_msg(u8 *data, int size) |
| 74 | { |
| 75 | struct ap_msg *ap_msg; |
| 76 | unsigned long flags; |
| 77 | |
| 78 | /* |
| 79 | * Totally naive copy the message into a new structure that we slowly |
| 80 | * create and add it to the list. Let's get this working, the odds of |
| 81 | * this being any "slow path" for AP messages is really low at this |
| 82 | * point in time, but you never know, so this comment is here to point |
| 83 | * out that maybe we should use a slab allocator, or even just not copy |
| 84 | * the data, but use it directly and force the urbs to be "new" each |
| 85 | * time. |
| 86 | */ |
| 87 | |
| 88 | /* Note - this can, and will, be called in interrupt context. */ |
| 89 | ap_msg = kmalloc(sizeof(*ap_msg), GFP_ATOMIC); |
| 90 | if (!ap_msg) |
| 91 | return -ENOMEM; |
| 92 | ap_msg->data = kmalloc(size, GFP_ATOMIC); |
| 93 | if (!ap_msg->data) { |
| 94 | kfree(ap_msg); |
| 95 | return -ENOMEM; |
| 96 | } |
| 97 | memcpy(ap_msg->data, data, size); |
| 98 | ap_msg->size = size; |
| 99 | |
| 100 | spin_lock_irqsave(&ap_msg_list_lock, flags); |
| 101 | list_add(&ap_msg->list, &ap_msg_list); |
| 102 | spin_unlock_irqrestore(&ap_msg_list_lock, flags); |
| 103 | |
| 104 | /* kick our thread to handle the message */ |
| 105 | wake_up_interruptible(&ap_wait); |
| 106 | |
| 107 | return 0; |
| 108 | } |
Greg Kroah-Hartman | d94a44a | 2014-09-01 14:39:34 -0700 | [diff] [blame^] | 109 | EXPORT_SYMBOL_GPL(gb_new_ap_msg); |
| 110 | |
Greg Kroah-Hartman | de536e3 | 2014-08-31 16:17:04 -0700 | [diff] [blame] | 111 | |
| 112 | int gb_thread_init(void) |
| 113 | { |
| 114 | init_waitqueue_head(&ap_wait); |
| 115 | spin_lock_init(&ap_msg_list_lock); |
| 116 | |
| 117 | ap_thread = kthread_run(ap_process_loop, NULL, "greybus_ap"); |
| 118 | if (IS_ERR(ap_thread)) |
| 119 | return PTR_ERR(ap_thread); |
| 120 | |
| 121 | return 0; |
| 122 | } |
| 123 | |
| 124 | void gb_thread_destroy(void) |
| 125 | { |
| 126 | kthread_stop(ap_thread); |
| 127 | } |
| 128 | |
| 129 | |