2 * linux/drivers/video/fb_defio.c
4 * Copyright (C) 2006 Jaya Kumar
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
11 #include <linux/module.h>
12 #include <linux/kernel.h>
13 #include <linux/errno.h>
14 #include <linux/string.h>
16 #include <linux/slab.h>
17 #include <linux/vmalloc.h>
18 #include <linux/delay.h>
19 #include <linux/interrupt.h>
21 #include <linux/list.h>
22 #include <asm/uaccess.h>
24 /* to support deferred IO */
25 #include <linux/rmap.h>
26 #include <linux/pagemap.h>
28 /* this is to find and return the vmalloc-ed fb pages */
29 static struct page* fb_deferred_io_nopage(struct vm_area_struct *vma,
30 unsigned long vaddr, int *type)
34 struct fb_info *info = vma->vm_private_data;
36 offset = (vaddr - vma->vm_start) + (vma->vm_pgoff << PAGE_SHIFT);
37 if (offset >= info->fix.smem_len)
40 page = vmalloc_to_page(info->screen_base + offset);
46 *type = VM_FAULT_MINOR;
50 /* vm_ops->page_mkwrite handler */
51 int fb_deferred_io_mkwrite(struct vm_area_struct *vma,
54 struct fb_info *info = vma->vm_private_data;
55 struct fb_deferred_io *fbdefio = info->fbdefio;
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 */
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);
68 /* come back after delay to process the deferred IO */
69 schedule_delayed_work(&info->deferred_work, fbdefio->delay);
73 static struct vm_operations_struct fb_deferred_io_vm_ops = {
74 .nopage = fb_deferred_io_nopage,
75 .page_mkwrite = fb_deferred_io_mkwrite,
78 static int fb_deferred_io_mmap(struct fb_info *info, struct vm_area_struct *vma)
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;
86 /* workqueue callback */
87 static void fb_deferred_io_work(struct work_struct *work)
89 struct fb_info *info = container_of(work, struct fb_info,
91 struct list_head *node, *next;
93 struct fb_deferred_io *fbdefio = info->fbdefio;
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) {
103 /* driver's callback with pagelist */
104 fbdefio->deferred_io(info, &fbdefio->pagelist);
107 list_for_each_safe(node, next, &fbdefio->pagelist) {
110 mutex_unlock(&fbdefio->lock);
113 void fb_deferred_io_init(struct fb_info *info)
115 struct fb_deferred_io *fbdefio = info->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 */
125 EXPORT_SYMBOL_GPL(fb_deferred_io_init);
127 void fb_deferred_io_cleanup(struct fb_info *info)
129 struct fb_deferred_io *fbdefio = info->fbdefio;
132 cancel_delayed_work(&info->deferred_work);
133 flush_scheduled_work();
135 EXPORT_SYMBOL_GPL(fb_deferred_io_cleanup);
137 MODULE_LICENSE("GPL");