blob: 0a7a6679ee6eb05e2be754ff816ba3547a0f7fdb [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
Jaya Kumarde7c6d12008-03-19 17:01:10 -07007 * License. See the file COPYING in the main directory of this archive
Jaya Kumar60b59be2007-05-08 00:37:37 -07008 * 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>
Jaya Kumar60b59be2007-05-08 00:37:37 -070022
23/* to support deferred IO */
24#include <linux/rmap.h>
25#include <linux/pagemap.h>
26
Magnus Damm37b48372008-12-19 15:34:32 +090027struct page *fb_deferred_io_page(struct fb_info *info, unsigned long offs)
28{
29 void *screen_base = (void __force *) info->screen_base;
30 struct page *page;
31
32 if (is_vmalloc_addr(screen_base + offs))
33 page = vmalloc_to_page(screen_base + offs);
34 else
35 page = pfn_to_page((info->fix.smem_start + offs) >> PAGE_SHIFT);
36
37 return page;
38}
39
Jaya Kumar60b59be2007-05-08 00:37:37 -070040/* this is to find and return the vmalloc-ed fb pages */
Nick Piggin529e55b2008-02-06 01:39:10 -080041static int fb_deferred_io_fault(struct vm_area_struct *vma,
42 struct vm_fault *vmf)
Jaya Kumar60b59be2007-05-08 00:37:37 -070043{
44 unsigned long offset;
45 struct page *page;
46 struct fb_info *info = vma->vm_private_data;
47
Nick Piggin529e55b2008-02-06 01:39:10 -080048 offset = vmf->pgoff << PAGE_SHIFT;
Jaya Kumar60b59be2007-05-08 00:37:37 -070049 if (offset >= info->fix.smem_len)
Nick Piggin529e55b2008-02-06 01:39:10 -080050 return VM_FAULT_SIGBUS;
Jaya Kumar60b59be2007-05-08 00:37:37 -070051
Magnus Damm37b48372008-12-19 15:34:32 +090052 page = fb_deferred_io_page(info, offset);
Jaya Kumar60b59be2007-05-08 00:37:37 -070053 if (!page)
Nick Piggin529e55b2008-02-06 01:39:10 -080054 return VM_FAULT_SIGBUS;
Jaya Kumar60b59be2007-05-08 00:37:37 -070055
56 get_page(page);
Jaya Kumarde7c6d12008-03-19 17:01:10 -070057
58 if (vma->vm_file)
59 page->mapping = vma->vm_file->f_mapping;
60 else
61 printk(KERN_ERR "no mapping available\n");
62
63 BUG_ON(!page->mapping);
64 page->index = vmf->pgoff;
65
Nick Piggin529e55b2008-02-06 01:39:10 -080066 vmf->page = page;
67 return 0;
Jaya Kumar60b59be2007-05-08 00:37:37 -070068}
69
Paul Mundt5e841b82007-05-08 00:37:41 -070070int fb_deferred_io_fsync(struct file *file, struct dentry *dentry, int datasync)
71{
72 struct fb_info *info = file->private_data;
73
Magnus Damm87884bd2008-12-19 15:34:09 +090074 /* Skip if deferred io is complied-in but disabled on this fbdev */
75 if (!info->fbdefio)
76 return 0;
77
Paul Mundt5e841b82007-05-08 00:37:41 -070078 /* Kill off the delayed work */
79 cancel_rearming_delayed_work(&info->deferred_work);
80
81 /* Run it immediately */
82 return schedule_delayed_work(&info->deferred_work, 0);
83}
84EXPORT_SYMBOL_GPL(fb_deferred_io_fsync);
85
Jaya Kumar60b59be2007-05-08 00:37:37 -070086/* vm_ops->page_mkwrite handler */
Adrian Bunk7bf1ea32007-05-08 00:37:38 -070087static int fb_deferred_io_mkwrite(struct vm_area_struct *vma,
Nick Pigginc2ec1752009-03-31 15:23:21 -070088 struct vm_fault *vmf)
Jaya Kumar60b59be2007-05-08 00:37:37 -070089{
Nick Pigginc2ec1752009-03-31 15:23:21 -070090 struct page *page = vmf->page;
Jaya Kumar60b59be2007-05-08 00:37:37 -070091 struct fb_info *info = vma->vm_private_data;
92 struct fb_deferred_io *fbdefio = info->fbdefio;
Jaya Kumarf31ad922008-07-12 13:47:51 -070093 struct page *cur;
Jaya Kumar60b59be2007-05-08 00:37:37 -070094
95 /* this is a callback we get when userspace first tries to
96 write to the page. we schedule a workqueue. that workqueue
97 will eventually mkclean the touched pages and execute the
98 deferred framebuffer IO. then if userspace touches a page
99 again, we repeat the same scheme */
100
101 /* protect against the workqueue changing the page list */
102 mutex_lock(&fbdefio->lock);
Jaya Kumarf31ad922008-07-12 13:47:51 -0700103
104 /* we loop through the pagelist before adding in order
105 to keep the pagelist sorted */
106 list_for_each_entry(cur, &fbdefio->pagelist, lru) {
107 /* this check is to catch the case where a new
108 process could start writing to the same page
109 through a new pte. this new access can cause the
110 mkwrite even when the original ps's pte is marked
111 writable */
112 if (unlikely(cur == page))
113 goto page_already_added;
114 else if (cur->index > page->index)
115 break;
116 }
117
118 list_add_tail(&page->lru, &cur->lru);
119
120page_already_added:
Jaya Kumar60b59be2007-05-08 00:37:37 -0700121 mutex_unlock(&fbdefio->lock);
122
123 /* come back after delay to process the deferred IO */
124 schedule_delayed_work(&info->deferred_work, fbdefio->delay);
125 return 0;
126}
127
128static struct vm_operations_struct fb_deferred_io_vm_ops = {
Nick Piggin529e55b2008-02-06 01:39:10 -0800129 .fault = fb_deferred_io_fault,
Jaya Kumar60b59be2007-05-08 00:37:37 -0700130 .page_mkwrite = fb_deferred_io_mkwrite,
131};
132
Ian Campbelld8474712008-08-20 14:09:23 -0700133static int fb_deferred_io_set_page_dirty(struct page *page)
134{
135 if (!PageDirty(page))
136 SetPageDirty(page);
137 return 0;
138}
139
140static const struct address_space_operations fb_deferred_io_aops = {
141 .set_page_dirty = fb_deferred_io_set_page_dirty,
142};
143
Jaya Kumar60b59be2007-05-08 00:37:37 -0700144static int fb_deferred_io_mmap(struct fb_info *info, struct vm_area_struct *vma)
145{
146 vma->vm_ops = &fb_deferred_io_vm_ops;
147 vma->vm_flags |= ( VM_IO | VM_RESERVED | VM_DONTEXPAND );
148 vma->vm_private_data = info;
149 return 0;
150}
151
152/* workqueue callback */
153static void fb_deferred_io_work(struct work_struct *work)
154{
155 struct fb_info *info = container_of(work, struct fb_info,
156 deferred_work.work);
157 struct list_head *node, *next;
158 struct page *cur;
159 struct fb_deferred_io *fbdefio = info->fbdefio;
160
161 /* here we mkclean the pages, then do all deferred IO */
162 mutex_lock(&fbdefio->lock);
163 list_for_each_entry(cur, &fbdefio->pagelist, lru) {
164 lock_page(cur);
165 page_mkclean(cur);
166 unlock_page(cur);
167 }
168
169 /* driver's callback with pagelist */
170 fbdefio->deferred_io(info, &fbdefio->pagelist);
171
172 /* clear the list */
173 list_for_each_safe(node, next, &fbdefio->pagelist) {
174 list_del(node);
175 }
176 mutex_unlock(&fbdefio->lock);
177}
178
179void fb_deferred_io_init(struct fb_info *info)
180{
181 struct fb_deferred_io *fbdefio = info->fbdefio;
182
183 BUG_ON(!fbdefio);
184 mutex_init(&fbdefio->lock);
185 info->fbops->fb_mmap = fb_deferred_io_mmap;
186 INIT_DELAYED_WORK(&info->deferred_work, fb_deferred_io_work);
187 INIT_LIST_HEAD(&fbdefio->pagelist);
188 if (fbdefio->delay == 0) /* set a default of 1 s */
189 fbdefio->delay = HZ;
190}
191EXPORT_SYMBOL_GPL(fb_deferred_io_init);
192
Ian Campbelld8474712008-08-20 14:09:23 -0700193void fb_deferred_io_open(struct fb_info *info,
194 struct inode *inode,
195 struct file *file)
196{
197 file->f_mapping->a_ops = &fb_deferred_io_aops;
198}
199EXPORT_SYMBOL_GPL(fb_deferred_io_open);
200
Jaya Kumar60b59be2007-05-08 00:37:37 -0700201void fb_deferred_io_cleanup(struct fb_info *info)
202{
203 struct fb_deferred_io *fbdefio = info->fbdefio;
Jaya Kumarde7c6d12008-03-19 17:01:10 -0700204 struct page *page;
205 int i;
Jaya Kumar60b59be2007-05-08 00:37:37 -0700206
207 BUG_ON(!fbdefio);
208 cancel_delayed_work(&info->deferred_work);
209 flush_scheduled_work();
Jaya Kumarde7c6d12008-03-19 17:01:10 -0700210
211 /* clear out the mapping that we setup */
212 for (i = 0 ; i < info->fix.smem_len; i += PAGE_SIZE) {
Magnus Damm37b48372008-12-19 15:34:32 +0900213 page = fb_deferred_io_page(info, i);
Jaya Kumarde7c6d12008-03-19 17:01:10 -0700214 page->mapping = NULL;
215 }
Magnus Damm6e1038a2008-12-19 15:34:23 +0900216
217 info->fbops->fb_mmap = NULL;
218 mutex_destroy(&fbdefio->lock);
Jaya Kumar60b59be2007-05-08 00:37:37 -0700219}
220EXPORT_SYMBOL_GPL(fb_deferred_io_cleanup);
221
222MODULE_LICENSE("GPL");