[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / video / fb_defio.c

/*
 *  linux/drivers/video/fb_defio.c
 *
 *  Copyright (C) 2006 Jaya Kumar
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License. See the file COPYING in the main directory of this archive
 * for more details.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/vmalloc.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/fb.h>
#include <linux/list.h>

/* to support deferred IO */
#include <linux/rmap.h>
#include <linux/pagemap.h>

static struct page *fb_deferred_io_page(struct fb_info *info, unsigned long offs)
{
	void *screen_base = (void __force *) info->screen_base;
	struct page *page;

	if (is_vmalloc_addr(screen_base + offs))
		page = vmalloc_to_page(screen_base + offs);
	else
		page = pfn_to_page((info->fix.smem_start + offs) >> PAGE_SHIFT);

	return page;
}

/* this is to find and return the vmalloc-ed fb pages */
static int fb_deferred_io_fault(struct vm_area_struct *vma,
				struct vm_fault *vmf)
{
	unsigned long offset;
	struct page *page;
	struct fb_info *info = vma->vm_private_data;

	offset = vmf->pgoff << PAGE_SHIFT;
	if (offset >= info->fix.smem_len)
		return VM_FAULT_SIGBUS;

	page = fb_deferred_io_page(info, offset);
	if (!page)
		return VM_FAULT_SIGBUS;

	get_page(page);

	if (vma->vm_file)
		page->mapping = vma->vm_file->f_mapping;
	else
		printk(KERN_ERR "no mapping available\n");

	BUG_ON(!page->mapping);
	page->index = vmf->pgoff;

	vmf->page = page;
	return 0;
}

int fb_deferred_io_fsync(struct file *file, loff_t start, loff_t end, int datasync)
{
	struct fb_info *info = file->private_data;
	struct inode *inode = file_inode(file);
	int err = filemap_write_and_wait_range(inode->i_mapping, start, end);
	if (err)
		return err;

	/* Skip if deferred io is compiled-in but disabled on this fbdev */
	if (!info->fbdefio)
		return 0;

	mutex_lock(&inode->i_mutex);
	/* Kill off the delayed work */
	cancel_delayed_work_sync(&info->deferred_work);

	/* Run it immediately */
	err = schedule_delayed_work(&info->deferred_work, 0);
	mutex_unlock(&inode->i_mutex);
	return err;
}
EXPORT_SYMBOL_GPL(fb_deferred_io_fsync);

/* vm_ops->page_mkwrite handler */
static int fb_deferred_io_mkwrite(struct vm_area_struct *vma,
				  struct vm_fault *vmf)
{
	struct page *page = vmf->page;
	struct fb_info *info = vma->vm_private_data;
	struct fb_deferred_io *fbdefio = info->fbdefio;
	struct page *cur;

	/* this is a callback we get when userspace first tries to
	write to the page. we schedule a workqueue. that workqueue
	will eventually mkclean the touched pages and execute the
	deferred framebuffer IO. then if userspace touches a page
	again, we repeat the same scheme */

	file_update_time(vma->vm_file);

	/* protect against the workqueue changing the page list */
	mutex_lock(&fbdefio->lock);

	/* first write in this cycle, notify the driver */
	if (fbdefio->first_io && list_empty(&fbdefio->pagelist))
		fbdefio->first_io(info);

	/*
	 * We want the page to remain locked from ->page_mkwrite until
	 * the PTE is marked dirty to avoid page_mkclean() being called
	 * before the PTE is updated, which would leave the page ignored
	 * by defio.
	 * Do this by locking the page here and informing the caller
	 * about it with VM_FAULT_LOCKED.
	 */
	lock_page(page);

	/* we loop through the pagelist before adding in order
	to keep the pagelist sorted */
	list_for_each_entry(cur, &fbdefio->pagelist, lru) {
		/* this check is to catch the case where a new
		process could start writing to the same page
		through a new pte. this new access can cause the
		mkwrite even when the original ps's pte is marked
		writable */
		if (unlikely(cur == page))
			goto page_already_added;
		else if (cur->index > page->index)
			break;
	}

	list_add_tail(&page->lru, &cur->lru);

page_already_added:
	mutex_unlock(&fbdefio->lock);

	/* come back after delay to process the deferred IO */
	schedule_delayed_work(&info->deferred_work, fbdefio->delay);
	return VM_FAULT_LOCKED;
}

static const struct vm_operations_struct fb_deferred_io_vm_ops = {
	.fault		= fb_deferred_io_fault,
	.page_mkwrite	= fb_deferred_io_mkwrite,
};

static int fb_deferred_io_set_page_dirty(struct page *page)
{
	if (!PageDirty(page))
		SetPageDirty(page);
	return 0;
}

static const struct address_space_operations fb_deferred_io_aops = {
	.set_page_dirty = fb_deferred_io_set_page_dirty,
};

static int fb_deferred_io_mmap(struct fb_info *info, struct vm_area_struct *vma)
{
	vma->vm_ops = &fb_deferred_io_vm_ops;
	vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
	if (!(info->flags & FBINFO_VIRTFB))
		vma->vm_flags |= VM_IO;
	vma->vm_private_data = info;
	return 0;
}

/* workqueue callback */
static void fb_deferred_io_work(struct work_struct *work)
{
	struct fb_info *info = container_of(work, struct fb_info,
						deferred_work.work);
	struct list_head *node, *next;
	struct page *cur;
	struct fb_deferred_io *fbdefio = info->fbdefio;

	/* here we mkclean the pages, then do all deferred IO */
	mutex_lock(&fbdefio->lock);
	list_for_each_entry(cur, &fbdefio->pagelist, lru) {
		lock_page(cur);
		page_mkclean(cur);
		unlock_page(cur);
	}

	/* driver's callback with pagelist */
	fbdefio->deferred_io(info, &fbdefio->pagelist);

	/* clear the list */
	list_for_each_safe(node, next, &fbdefio->pagelist) {
		list_del(node);
	}
	mutex_unlock(&fbdefio->lock);
}

void fb_deferred_io_init(struct fb_info *info)
{
	struct fb_deferred_io *fbdefio = info->fbdefio;

	BUG_ON(!fbdefio);
	mutex_init(&fbdefio->lock);
	info->fbops->fb_mmap = fb_deferred_io_mmap;
	INIT_DELAYED_WORK(&info->deferred_work, fb_deferred_io_work);
	INIT_LIST_HEAD(&fbdefio->pagelist);
	if (fbdefio->delay == 0) /* set a default of 1 s */
		fbdefio->delay = HZ;
}
EXPORT_SYMBOL_GPL(fb_deferred_io_init);

void fb_deferred_io_open(struct fb_info *info,
			 struct inode *inode,
			 struct file *file)
{
	file->f_mapping->a_ops = &fb_deferred_io_aops;
}
EXPORT_SYMBOL_GPL(fb_deferred_io_open);

void fb_deferred_io_cleanup(struct fb_info *info)
{
	struct fb_deferred_io *fbdefio = info->fbdefio;
	struct page *page;
	int i;

	BUG_ON(!fbdefio);
	cancel_delayed_work_sync(&info->deferred_work);

	/* clear out the mapping that we setup */
	for (i = 0 ; i < info->fix.smem_len; i += PAGE_SIZE) {
		page = fb_deferred_io_page(info, i);
		page->mapping = NULL;
	}

	info->fbops->fb_mmap = NULL;
	mutex_destroy(&fbdefio->lock);
}
EXPORT_SYMBOL_GPL(fb_deferred_io_cleanup);

MODULE_LICENSE("GPL");
Commit	Line	Data
60b59bea JK	1	/*
	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
de7c6d15	7	* License. See the file COPYING in the main directory of this archive
60b59bea JK	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>
60b59bea JK	16	#include <linux/vmalloc.h>
	17	#include <linux/delay.h>
	18	#include <linux/interrupt.h>
	19	#include <linux/fb.h>
	20	#include <linux/list.h>
60b59bea JK	21
	22	/* to support deferred IO */
	23	#include <linux/rmap.h>
	24	#include <linux/pagemap.h>
	25
43b1aee0	26	static struct page fb_deferred_io_page(struct fb_info info, unsigned long offs)
37b48379 MD	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
60b59bea	39	/* this is to find and return the vmalloc-ed fb pages */
529e55b6 NP	40	static int fb_deferred_io_fault(struct vm_area_struct *vma,
529e55b6 NP	41	struct vm_fault *vmf)
60b59bea JK	42	{
	43	unsigned long offset;
	44	struct page *page;
	45	struct fb_info *info = vma->vm_private_data;
	46
529e55b6	47	offset = vmf->pgoff << PAGE_SHIFT;
60b59bea	48	if (offset >= info->fix.smem_len)
529e55b6	49	return VM_FAULT_SIGBUS;
60b59bea	50
37b48379	51	page = fb_deferred_io_page(info, offset);
60b59bea	52	if (!page)
529e55b6	53	return VM_FAULT_SIGBUS;
60b59bea JK	54
60b59bea JK	55	get_page(page);
de7c6d15 JK	56
	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
529e55b6 NP	65	vmf->page = page;
529e55b6 NP	66	return 0;
60b59bea JK	67	}
60b59bea JK	68
02c24a82	69	int fb_deferred_io_fsync(struct file *file, loff_t start, loff_t end, int datasync)
5e841b88 PM	70	{
5e841b88 PM	71	struct fb_info *info = file->private_data;
496ad9aa	72	struct inode *inode = file_inode(file);
02c24a82 JB	73	int err = filemap_write_and_wait_range(inode->i_mapping, start, end);
	74	if (err)
	75	return err;
5e841b88	76
94e2bd68	77	/* Skip if deferred io is compiled-in but disabled on this fbdev */
87884bd8 MD	78	if (!info->fbdefio)
	79	return 0;
	80
02c24a82	81	mutex_lock(&inode->i_mutex);
5e841b88	82	/* Kill off the delayed work */
afe2c511	83	cancel_delayed_work_sync(&info->deferred_work);
5e841b88 PM	84
5e841b88 PM	85	/* Run it immediately */
02c24a82 JB	86	err = schedule_delayed_work(&info->deferred_work, 0);
	87	mutex_unlock(&inode->i_mutex);
	88	return err;
5e841b88 PM	89	}
	90	EXPORT_SYMBOL_GPL(fb_deferred_io_fsync);
	91
60b59bea	92	/* vm_ops->page_mkwrite handler */
7bf1ea33	93	static int fb_deferred_io_mkwrite(struct vm_area_struct *vma,
c2ec175c	94	struct vm_fault *vmf)
60b59bea	95	{
c2ec175c	96	struct page *page = vmf->page;
60b59bea JK	97	struct fb_info *info = vma->vm_private_data;
60b59bea JK	98	struct fb_deferred_io *fbdefio = info->fbdefio;
f31ad92f	99	struct page *cur;
60b59bea JK	100
	101	/* this is a callback we get when userspace first tries to
	102	write to the page. we schedule a workqueue. that workqueue
	103	will eventually mkclean the touched pages and execute the
	104	deferred framebuffer IO. then if userspace touches a page
	105	again, we repeat the same scheme */
	106
183fef91 JK	107	file_update_time(vma->vm_file);
183fef91 JK	108
60b59bea JK	109	/* protect against the workqueue changing the page list */
60b59bea JK	110	mutex_lock(&fbdefio->lock);
f31ad92f	111
1f45f9db HS	112	/* first write in this cycle, notify the driver */
	113	if (fbdefio->first_io && list_empty(&fbdefio->pagelist))
	114	fbdefio->first_io(info);
	115
d6d03f91 AH	116	/*
	117	* We want the page to remain locked from ->page_mkwrite until
	118	* the PTE is marked dirty to avoid page_mkclean() being called
	119	* before the PTE is updated, which would leave the page ignored
	120	* by defio.
	121	* Do this by locking the page here and informing the caller
	122	* about it with VM_FAULT_LOCKED.
	123	*/
	124	lock_page(page);
	125
f31ad92f JK	126	/* we loop through the pagelist before adding in order
	127	to keep the pagelist sorted */
	128	list_for_each_entry(cur, &fbdefio->pagelist, lru) {
	129	/* this check is to catch the case where a new
	130	process could start writing to the same page
	131	through a new pte. this new access can cause the
	132	mkwrite even when the original ps's pte is marked
	133	writable */
	134	if (unlikely(cur == page))
	135	goto page_already_added;
	136	else if (cur->index > page->index)
	137	break;
	138	}
	139
	140	list_add_tail(&page->lru, &cur->lru);
	141
	142	page_already_added:
60b59bea JK	143	mutex_unlock(&fbdefio->lock);
	144
	145	/* come back after delay to process the deferred IO */
	146	schedule_delayed_work(&info->deferred_work, fbdefio->delay);
d6d03f91	147	return VM_FAULT_LOCKED;
60b59bea JK	148	}
60b59bea JK	149
f0f37e2f	150	static const struct vm_operations_struct fb_deferred_io_vm_ops = {
529e55b6	151	.fault = fb_deferred_io_fault,
60b59bea JK	152	.page_mkwrite = fb_deferred_io_mkwrite,
	153	};
	154
d847471d IC	155	static int fb_deferred_io_set_page_dirty(struct page *page)
	156	{
	157	if (!PageDirty(page))
	158	SetPageDirty(page);
	159	return 0;
	160	}
	161
	162	static const struct address_space_operations fb_deferred_io_aops = {
	163	.set_page_dirty = fb_deferred_io_set_page_dirty,
	164	};
	165
60b59bea JK	166	static int fb_deferred_io_mmap(struct fb_info info, struct vm_area_struct vma)
	167	{
	168	vma->vm_ops = &fb_deferred_io_vm_ops;
314e51b9	169	vma->vm_flags \|= VM_DONTEXPAND \| VM_DONTDUMP;
7164bb43 KRW	170	if (!(info->flags & FBINFO_VIRTFB))
7164bb43 KRW	171	vma->vm_flags \|= VM_IO;
60b59bea JK	172	vma->vm_private_data = info;
	173	return 0;
	174	}
	175
	176	/* workqueue callback */
	177	static void fb_deferred_io_work(struct work_struct *work)
	178	{
	179	struct fb_info *info = container_of(work, struct fb_info,
	180	deferred_work.work);
3f505ca4 AH	181	struct list_head node, next;
3f505ca4 AH	182	struct page *cur;
60b59bea JK	183	struct fb_deferred_io *fbdefio = info->fbdefio;
	184
	185	/* here we mkclean the pages, then do all deferred IO */
	186	mutex_lock(&fbdefio->lock);
3f505ca4 AH	187	list_for_each_entry(cur, &fbdefio->pagelist, lru) {
	188	lock_page(cur);
	189	page_mkclean(cur);
	190	unlock_page(cur);
60b59bea JK	191	}
	192
	193	/* driver's callback with pagelist */
	194	fbdefio->deferred_io(info, &fbdefio->pagelist);
	195
3f505ca4 AH	196	/* clear the list */
3f505ca4 AH	197	list_for_each_safe(node, next, &fbdefio->pagelist) {
60b59bea JK	198	list_del(node);
	199	}
	200	mutex_unlock(&fbdefio->lock);
	201	}
	202
	203	void fb_deferred_io_init(struct fb_info *info)
	204	{
	205	struct fb_deferred_io *fbdefio = info->fbdefio;
	206
	207	BUG_ON(!fbdefio);
	208	mutex_init(&fbdefio->lock);
	209	info->fbops->fb_mmap = fb_deferred_io_mmap;
	210	INIT_DELAYED_WORK(&info->deferred_work, fb_deferred_io_work);
	211	INIT_LIST_HEAD(&fbdefio->pagelist);
	212	if (fbdefio->delay == 0) /* set a default of 1 s */
	213	fbdefio->delay = HZ;
	214	}
	215	EXPORT_SYMBOL_GPL(fb_deferred_io_init);
	216
d847471d IC	217	void fb_deferred_io_open(struct fb_info *info,
	218	struct inode *inode,
	219	struct file *file)
	220	{
	221	file->f_mapping->a_ops = &fb_deferred_io_aops;
	222	}
	223	EXPORT_SYMBOL_GPL(fb_deferred_io_open);
	224
60b59bea JK	225	void fb_deferred_io_cleanup(struct fb_info *info)
	226	{
	227	struct fb_deferred_io *fbdefio = info->fbdefio;
de7c6d15 JK	228	struct page *page;
de7c6d15 JK	229	int i;
60b59bea JK	230
60b59bea JK	231	BUG_ON(!fbdefio);
181b74ef	232	cancel_delayed_work_sync(&info->deferred_work);
de7c6d15 JK	233
	234	/* clear out the mapping that we setup */
	235	for (i = 0 ; i < info->fix.smem_len; i += PAGE_SIZE) {
37b48379	236	page = fb_deferred_io_page(info, i);
de7c6d15 JK	237	page->mapping = NULL;
de7c6d15 JK	238	}
6e1038a9 MD	239
	240	info->fbops->fb_mmap = NULL;
	241	mutex_destroy(&fbdefio->lock);
60b59bea JK	242	}
	243	EXPORT_SYMBOL_GPL(fb_deferred_io_cleanup);
	244
	245	MODULE_LICENSE("GPL");