blob: 6b93ef93cb12c08179c973e31bf97ff27eb4d56b [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>
Jaya Kumar60b59be2007-05-08 00:37:37 -070016#include <linux/vmalloc.h>
17#include <linux/delay.h>
18#include <linux/interrupt.h>
19#include <linux/fb.h>
20#include <linux/list.h>
Jaya Kumar60b59be2007-05-08 00:37:37 -070021
22/* to support deferred IO */
23#include <linux/rmap.h>
24#include <linux/pagemap.h>
25
Magnus Damm37b48372008-12-19 15:34:32 +090026struct page *fb_deferred_io_page(struct fb_info *info, unsigned long offs)
27{
28 void *screen_base = (void __force *) info->screen_base;
29 struct page *page;
30
31 if (is_vmalloc_addr(screen_base + offs))
32 page = vmalloc_to_page(screen_base + offs);
33 else
34 page = pfn_to_page((info->fix.smem_start + offs) >> PAGE_SHIFT);
35
36 return page;
37}
38
Jaya Kumar60b59be2007-05-08 00:37:37 -070039/* this is to find and return the vmalloc-ed fb pages */
Nick Piggin529e55b2008-02-06 01:39:10 -080040static int fb_deferred_io_fault(struct vm_area_struct *vma,
41 struct vm_fault *vmf)
Jaya Kumar60b59be2007-05-08 00:37:37 -070042{
43 unsigned long offset;
44 struct page *page;
45 struct fb_info *info = vma->vm_private_data;
46
Nick Piggin529e55b2008-02-06 01:39:10 -080047 offset = vmf->pgoff << PAGE_SHIFT;
Jaya Kumar60b59be2007-05-08 00:37:37 -070048 if (offset >= info->fix.smem_len)
Nick Piggin529e55b2008-02-06 01:39:10 -080049 return VM_FAULT_SIGBUS;
Jaya Kumar60b59be2007-05-08 00:37:37 -070050
Magnus Damm37b48372008-12-19 15:34:32 +090051 page = fb_deferred_io_page(info, offset);
Jaya Kumar60b59be2007-05-08 00:37:37 -070052 if (!page)
Nick Piggin529e55b2008-02-06 01:39:10 -080053 return VM_FAULT_SIGBUS;
Jaya Kumar60b59be2007-05-08 00:37:37 -070054
55 get_page(page);
Jaya Kumarde7c6d12008-03-19 17:01:10 -070056
57 if (vma->vm_file)
58 page->mapping = vma->vm_file->f_mapping;
59 else
60 printk(KERN_ERR "no mapping available\n");
61
62 BUG_ON(!page->mapping);
63 page->index = vmf->pgoff;
64
Nick Piggin529e55b2008-02-06 01:39:10 -080065 vmf->page = page;
66 return 0;
Jaya Kumar60b59be2007-05-08 00:37:37 -070067}
68
Christoph Hellwig7ea80852010-05-26 17:53:25 +020069int fb_deferred_io_fsync(struct file *file, int datasync)
Paul Mundt5e841b82007-05-08 00:37:41 -070070{
71 struct fb_info *info = file->private_data;
72
Thadeu Lima de Souza Cascardo94e2bd62009-10-16 15:20:49 +020073 /* Skip if deferred io is compiled-in but disabled on this fbdev */
Magnus Damm87884bd2008-12-19 15:34:09 +090074 if (!info->fbdefio)
75 return 0;
76
Paul Mundt5e841b82007-05-08 00:37:41 -070077 /* Kill off the delayed work */
78 cancel_rearming_delayed_work(&info->deferred_work);
79
80 /* Run it immediately */
81 return schedule_delayed_work(&info->deferred_work, 0);
82}
83EXPORT_SYMBOL_GPL(fb_deferred_io_fsync);
84
Jaya Kumar60b59be2007-05-08 00:37:37 -070085/* vm_ops->page_mkwrite handler */
Adrian Bunk7bf1ea32007-05-08 00:37:38 -070086static int fb_deferred_io_mkwrite(struct vm_area_struct *vma,
Nick Pigginc2ec1752009-03-31 15:23:21 -070087 struct vm_fault *vmf)
Jaya Kumar60b59be2007-05-08 00:37:37 -070088{
Nick Pigginc2ec1752009-03-31 15:23:21 -070089 struct page *page = vmf->page;
Jaya Kumar60b59be2007-05-08 00:37:37 -070090 struct fb_info *info = vma->vm_private_data;
91 struct fb_deferred_io *fbdefio = info->fbdefio;
Jaya Kumarf31ad922008-07-12 13:47:51 -070092 struct page *cur;
Jaya Kumar60b59be2007-05-08 00:37:37 -070093
94 /* this is a callback we get when userspace first tries to
95 write to the page. we schedule a workqueue. that workqueue
96 will eventually mkclean the touched pages and execute the
97 deferred framebuffer IO. then if userspace touches a page
98 again, we repeat the same scheme */
99
100 /* protect against the workqueue changing the page list */
101 mutex_lock(&fbdefio->lock);
Jaya Kumarf31ad922008-07-12 13:47:51 -0700102
Albert Herranzd6d03f92010-06-04 14:14:57 -0700103 /*
104 * We want the page to remain locked from ->page_mkwrite until
105 * the PTE is marked dirty to avoid page_mkclean() being called
106 * before the PTE is updated, which would leave the page ignored
107 * by defio.
108 * Do this by locking the page here and informing the caller
109 * about it with VM_FAULT_LOCKED.
110 */
111 lock_page(page);
112
Jaya Kumarf31ad922008-07-12 13:47:51 -0700113 /* we loop through the pagelist before adding in order
114 to keep the pagelist sorted */
115 list_for_each_entry(cur, &fbdefio->pagelist, lru) {
116 /* this check is to catch the case where a new
117 process could start writing to the same page
118 through a new pte. this new access can cause the
119 mkwrite even when the original ps's pte is marked
120 writable */
121 if (unlikely(cur == page))
122 goto page_already_added;
123 else if (cur->index > page->index)
124 break;
125 }
126
127 list_add_tail(&page->lru, &cur->lru);
128
129page_already_added:
Jaya Kumar60b59be2007-05-08 00:37:37 -0700130 mutex_unlock(&fbdefio->lock);
131
132 /* come back after delay to process the deferred IO */
133 schedule_delayed_work(&info->deferred_work, fbdefio->delay);
Albert Herranzd6d03f92010-06-04 14:14:57 -0700134 return VM_FAULT_LOCKED;
Jaya Kumar60b59be2007-05-08 00:37:37 -0700135}
136
Alexey Dobriyanf0f37e22009-09-27 22:29:37 +0400137static const struct vm_operations_struct fb_deferred_io_vm_ops = {
Nick Piggin529e55b2008-02-06 01:39:10 -0800138 .fault = fb_deferred_io_fault,
Jaya Kumar60b59be2007-05-08 00:37:37 -0700139 .page_mkwrite = fb_deferred_io_mkwrite,
140};
141
Ian Campbelld8474712008-08-20 14:09:23 -0700142static int fb_deferred_io_set_page_dirty(struct page *page)
143{
144 if (!PageDirty(page))
145 SetPageDirty(page);
146 return 0;
147}
148
149static const struct address_space_operations fb_deferred_io_aops = {
150 .set_page_dirty = fb_deferred_io_set_page_dirty,
151};
152
Jaya Kumar60b59be2007-05-08 00:37:37 -0700153static int fb_deferred_io_mmap(struct fb_info *info, struct vm_area_struct *vma)
154{
155 vma->vm_ops = &fb_deferred_io_vm_ops;
Konrad Rzeszutek Wilk7164bb42009-12-03 10:31:56 -0500156 vma->vm_flags |= ( VM_RESERVED | VM_DONTEXPAND );
157 if (!(info->flags & FBINFO_VIRTFB))
158 vma->vm_flags |= VM_IO;
Jaya Kumar60b59be2007-05-08 00:37:37 -0700159 vma->vm_private_data = info;
160 return 0;
161}
162
163/* workqueue callback */
164static void fb_deferred_io_work(struct work_struct *work)
165{
166 struct fb_info *info = container_of(work, struct fb_info,
167 deferred_work.work);
Albert Herranz3f505ca2010-06-04 14:14:56 -0700168 struct list_head *node, *next;
169 struct page *cur;
Jaya Kumar60b59be2007-05-08 00:37:37 -0700170 struct fb_deferred_io *fbdefio = info->fbdefio;
171
172 /* here we mkclean the pages, then do all deferred IO */
173 mutex_lock(&fbdefio->lock);
Albert Herranz3f505ca2010-06-04 14:14:56 -0700174 list_for_each_entry(cur, &fbdefio->pagelist, lru) {
175 lock_page(cur);
176 page_mkclean(cur);
177 unlock_page(cur);
Jaya Kumar60b59be2007-05-08 00:37:37 -0700178 }
179
180 /* driver's callback with pagelist */
181 fbdefio->deferred_io(info, &fbdefio->pagelist);
182
Albert Herranz3f505ca2010-06-04 14:14:56 -0700183 /* clear the list */
184 list_for_each_safe(node, next, &fbdefio->pagelist) {
Jaya Kumar60b59be2007-05-08 00:37:37 -0700185 list_del(node);
186 }
187 mutex_unlock(&fbdefio->lock);
188}
189
190void fb_deferred_io_init(struct fb_info *info)
191{
192 struct fb_deferred_io *fbdefio = info->fbdefio;
193
194 BUG_ON(!fbdefio);
195 mutex_init(&fbdefio->lock);
196 info->fbops->fb_mmap = fb_deferred_io_mmap;
197 INIT_DELAYED_WORK(&info->deferred_work, fb_deferred_io_work);
198 INIT_LIST_HEAD(&fbdefio->pagelist);
199 if (fbdefio->delay == 0) /* set a default of 1 s */
200 fbdefio->delay = HZ;
201}
202EXPORT_SYMBOL_GPL(fb_deferred_io_init);
203
Ian Campbelld8474712008-08-20 14:09:23 -0700204void fb_deferred_io_open(struct fb_info *info,
205 struct inode *inode,
206 struct file *file)
207{
208 file->f_mapping->a_ops = &fb_deferred_io_aops;
209}
210EXPORT_SYMBOL_GPL(fb_deferred_io_open);
211
Jaya Kumar60b59be2007-05-08 00:37:37 -0700212void fb_deferred_io_cleanup(struct fb_info *info)
213{
214 struct fb_deferred_io *fbdefio = info->fbdefio;
Jaya Kumarde7c6d12008-03-19 17:01:10 -0700215 struct page *page;
216 int i;
Jaya Kumar60b59be2007-05-08 00:37:37 -0700217
218 BUG_ON(!fbdefio);
219 cancel_delayed_work(&info->deferred_work);
220 flush_scheduled_work();
Jaya Kumarde7c6d12008-03-19 17:01:10 -0700221
222 /* clear out the mapping that we setup */
223 for (i = 0 ; i < info->fix.smem_len; i += PAGE_SIZE) {
Magnus Damm37b48372008-12-19 15:34:32 +0900224 page = fb_deferred_io_page(info, i);
Jaya Kumarde7c6d12008-03-19 17:01:10 -0700225 page->mapping = NULL;
226 }
Magnus Damm6e1038a2008-12-19 15:34:23 +0900227
228 info->fbops->fb_mmap = NULL;
229 mutex_destroy(&fbdefio->lock);
Jaya Kumar60b59be2007-05-08 00:37:37 -0700230}
231EXPORT_SYMBOL_GPL(fb_deferred_io_cleanup);
232
233MODULE_LICENSE("GPL");