blob: 65f4e6ee7f943540c3a09b87fc128f5aa0263ea8 [file] [log] [blame]
Jaya Kumar60b59be2007-05-08 00:37:37 -07001/*
2 * linux/drivers/video/fb_defio.c
3 *
4 * Copyright (C) 2006 Jaya Kumar
5 *
6 * This file is subject to the terms and conditions of the GNU General Public
7 * License. See the file COPYING in the main directory of this archive
8 * for more details.
9 */
10
11#include <linux/module.h>
12#include <linux/kernel.h>
13#include <linux/errno.h>
14#include <linux/string.h>
15#include <linux/mm.h>
16#include <linux/slab.h>
17#include <linux/vmalloc.h>
18#include <linux/delay.h>
19#include <linux/interrupt.h>
20#include <linux/fb.h>
21#include <linux/list.h>
22#include <asm/uaccess.h>
23
24/* to support deferred IO */
25#include <linux/rmap.h>
26#include <linux/pagemap.h>
27
28/* this is to find and return the vmalloc-ed fb pages */
29static struct page* fb_deferred_io_nopage(struct vm_area_struct *vma,
30 unsigned long vaddr, int *type)
31{
32 unsigned long offset;
33 struct page *page;
34 struct fb_info *info = vma->vm_private_data;
35
36 offset = (vaddr - vma->vm_start) + (vma->vm_pgoff << PAGE_SHIFT);
37 if (offset >= info->fix.smem_len)
38 return NOPAGE_SIGBUS;
39
40 page = vmalloc_to_page(info->screen_base + offset);
41 if (!page)
42 return NOPAGE_OOM;
43
44 get_page(page);
45 if (type)
46 *type = VM_FAULT_MINOR;
47 return page;
48}
49
50/* vm_ops->page_mkwrite handler */
Adrian Bunk7bf1ea32007-05-08 00:37:38 -070051static int fb_deferred_io_mkwrite(struct vm_area_struct *vma,
52 struct page *page)
Jaya Kumar60b59be2007-05-08 00:37:37 -070053{
54 struct fb_info *info = vma->vm_private_data;
55 struct fb_deferred_io *fbdefio = info->fbdefio;
56
57 /* this is a callback we get when userspace first tries to
58 write to the page. we schedule a workqueue. that workqueue
59 will eventually mkclean the touched pages and execute the
60 deferred framebuffer IO. then if userspace touches a page
61 again, we repeat the same scheme */
62
63 /* protect against the workqueue changing the page list */
64 mutex_lock(&fbdefio->lock);
65 list_add(&page->lru, &fbdefio->pagelist);
66 mutex_unlock(&fbdefio->lock);
67
68 /* come back after delay to process the deferred IO */
69 schedule_delayed_work(&info->deferred_work, fbdefio->delay);
70 return 0;
71}
72
73static struct vm_operations_struct fb_deferred_io_vm_ops = {
74 .nopage = fb_deferred_io_nopage,
75 .page_mkwrite = fb_deferred_io_mkwrite,
76};
77
78static int fb_deferred_io_mmap(struct fb_info *info, struct vm_area_struct *vma)
79{
80 vma->vm_ops = &fb_deferred_io_vm_ops;
81 vma->vm_flags |= ( VM_IO | VM_RESERVED | VM_DONTEXPAND );
82 vma->vm_private_data = info;
83 return 0;
84}
85
86/* workqueue callback */
87static void fb_deferred_io_work(struct work_struct *work)
88{
89 struct fb_info *info = container_of(work, struct fb_info,
90 deferred_work.work);
91 struct list_head *node, *next;
92 struct page *cur;
93 struct fb_deferred_io *fbdefio = info->fbdefio;
94
95 /* here we mkclean the pages, then do all deferred IO */
96 mutex_lock(&fbdefio->lock);
97 list_for_each_entry(cur, &fbdefio->pagelist, lru) {
98 lock_page(cur);
99 page_mkclean(cur);
100 unlock_page(cur);
101 }
102
103 /* driver's callback with pagelist */
104 fbdefio->deferred_io(info, &fbdefio->pagelist);
105
106 /* clear the list */
107 list_for_each_safe(node, next, &fbdefio->pagelist) {
108 list_del(node);
109 }
110 mutex_unlock(&fbdefio->lock);
111}
112
113void fb_deferred_io_init(struct fb_info *info)
114{
115 struct fb_deferred_io *fbdefio = info->fbdefio;
116
117 BUG_ON(!fbdefio);
118 mutex_init(&fbdefio->lock);
119 info->fbops->fb_mmap = fb_deferred_io_mmap;
120 INIT_DELAYED_WORK(&info->deferred_work, fb_deferred_io_work);
121 INIT_LIST_HEAD(&fbdefio->pagelist);
122 if (fbdefio->delay == 0) /* set a default of 1 s */
123 fbdefio->delay = HZ;
124}
125EXPORT_SYMBOL_GPL(fb_deferred_io_init);
126
127void fb_deferred_io_cleanup(struct fb_info *info)
128{
129 struct fb_deferred_io *fbdefio = info->fbdefio;
130
131 BUG_ON(!fbdefio);
132 cancel_delayed_work(&info->deferred_work);
133 flush_scheduled_work();
134}
135EXPORT_SYMBOL_GPL(fb_deferred_io_cleanup);
136
137MODULE_LICENSE("GPL");