150 lines
3.9 KiB
C
150 lines
3.9 KiB
C
/*
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* linux/drivers/video/fb_defio.c
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*
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* Copyright (C) 2006 Jaya Kumar
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file COPYING in the main directory of this archive
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* for more details.
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/string.h>
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#include <linux/mm.h>
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#include <linux/slab.h>
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#include <linux/vmalloc.h>
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#include <linux/delay.h>
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#include <linux/interrupt.h>
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#include <linux/fb.h>
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#include <linux/list.h>
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/* to support deferred IO */
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#include <linux/rmap.h>
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#include <linux/pagemap.h>
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/* this is to find and return the vmalloc-ed fb pages */
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static int fb_deferred_io_fault(struct vm_area_struct *vma,
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struct vm_fault *vmf)
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{
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unsigned long offset;
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struct page *page;
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struct fb_info *info = vma->vm_private_data;
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/* info->screen_base is in System RAM */
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void *screen_base = (void __force *) info->screen_base;
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offset = vmf->pgoff << PAGE_SHIFT;
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if (offset >= info->fix.smem_len)
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return VM_FAULT_SIGBUS;
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page = vmalloc_to_page(screen_base + offset);
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if (!page)
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return VM_FAULT_SIGBUS;
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get_page(page);
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vmf->page = page;
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return 0;
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}
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int fb_deferred_io_fsync(struct file *file, struct dentry *dentry, int datasync)
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{
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struct fb_info *info = file->private_data;
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/* Kill off the delayed work */
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cancel_rearming_delayed_work(&info->deferred_work);
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/* Run it immediately */
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return schedule_delayed_work(&info->deferred_work, 0);
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}
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EXPORT_SYMBOL_GPL(fb_deferred_io_fsync);
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/* vm_ops->page_mkwrite handler */
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static int fb_deferred_io_mkwrite(struct vm_area_struct *vma,
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struct page *page)
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{
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struct fb_info *info = vma->vm_private_data;
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struct fb_deferred_io *fbdefio = info->fbdefio;
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/* this is a callback we get when userspace first tries to
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write to the page. we schedule a workqueue. that workqueue
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will eventually mkclean the touched pages and execute the
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deferred framebuffer IO. then if userspace touches a page
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again, we repeat the same scheme */
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/* protect against the workqueue changing the page list */
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mutex_lock(&fbdefio->lock);
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list_add(&page->lru, &fbdefio->pagelist);
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mutex_unlock(&fbdefio->lock);
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/* come back after delay to process the deferred IO */
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schedule_delayed_work(&info->deferred_work, fbdefio->delay);
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return 0;
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}
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static struct vm_operations_struct fb_deferred_io_vm_ops = {
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.fault = fb_deferred_io_fault,
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.page_mkwrite = fb_deferred_io_mkwrite,
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};
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static int fb_deferred_io_mmap(struct fb_info *info, struct vm_area_struct *vma)
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{
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vma->vm_ops = &fb_deferred_io_vm_ops;
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vma->vm_flags |= ( VM_IO | VM_RESERVED | VM_DONTEXPAND );
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vma->vm_private_data = info;
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return 0;
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}
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/* workqueue callback */
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static void fb_deferred_io_work(struct work_struct *work)
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{
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struct fb_info *info = container_of(work, struct fb_info,
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deferred_work.work);
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struct list_head *node, *next;
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struct page *cur;
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struct fb_deferred_io *fbdefio = info->fbdefio;
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/* here we mkclean the pages, then do all deferred IO */
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mutex_lock(&fbdefio->lock);
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list_for_each_entry(cur, &fbdefio->pagelist, lru) {
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lock_page(cur);
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page_mkclean(cur);
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unlock_page(cur);
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}
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/* driver's callback with pagelist */
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fbdefio->deferred_io(info, &fbdefio->pagelist);
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/* clear the list */
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list_for_each_safe(node, next, &fbdefio->pagelist) {
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list_del(node);
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}
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mutex_unlock(&fbdefio->lock);
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}
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void fb_deferred_io_init(struct fb_info *info)
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{
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struct fb_deferred_io *fbdefio = info->fbdefio;
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BUG_ON(!fbdefio);
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mutex_init(&fbdefio->lock);
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info->fbops->fb_mmap = fb_deferred_io_mmap;
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INIT_DELAYED_WORK(&info->deferred_work, fb_deferred_io_work);
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INIT_LIST_HEAD(&fbdefio->pagelist);
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if (fbdefio->delay == 0) /* set a default of 1 s */
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fbdefio->delay = HZ;
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}
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EXPORT_SYMBOL_GPL(fb_deferred_io_init);
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void fb_deferred_io_cleanup(struct fb_info *info)
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{
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struct fb_deferred_io *fbdefio = info->fbdefio;
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BUG_ON(!fbdefio);
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cancel_delayed_work(&info->deferred_work);
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flush_scheduled_work();
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}
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EXPORT_SYMBOL_GPL(fb_deferred_io_cleanup);
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MODULE_LICENSE("GPL");
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