xen-fbfront.c

Linux环境下视频显示卡设备的驱动程序源代码

/*
 * Xen para-virtual frame buffer device
 *
 * Copyright (C) 2005-2006 Anthony Liguori <[e-mail]>
 * Copyright (C) 2006-2008 Red Hat, Inc., Markus Armbruster <[e-mail]>
 *
 *  Based on linux/drivers/video/q40fb.c
 *
 *  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.
 */

/*
 * TODO:
 *
 * Switch to grant tables when they become capable of dealing with the
 * frame buffer.
 */

#include <linux/console.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/fb.h>
#include <linux/module.h>
#include <linux/vmalloc.h>
#include <linux/mm.h>
#include <asm/xen/hypervisor.h>
#include <xen/events.h>
#include <xen/page.h>
#include <xen/interface/io/fbif.h>
#include <xen/interface/io/protocols.h>
#include <xen/xenbus.h>

struct xenfb_info {
	unsigned char		*fb;
	struct fb_info		*fb_info;
	int			x1, y1, x2, y2;	/* dirty rectangle,
						   protected by dirty_lock */
	spinlock_t		dirty_lock;
	int			nr_pages;
	int			irq;
	struct xenfb_page	*page;
	unsigned long 		*mfns;
	int			update_wanted; /* XENFB_TYPE_UPDATE wanted */
	int			feature_resize; /* XENFB_TYPE_RESIZE ok */
	struct xenfb_resize	resize;		/* protected by resize_lock */
	int			resize_dpy;	/* ditto */
	spinlock_t		resize_lock;

	struct xenbus_device	*xbdev;
};

#define XENFB_DEFAULT_FB_LEN (XENFB_WIDTH * XENFB_HEIGHT * XENFB_DEPTH / 8)

enum { KPARAM_MEM, KPARAM_WIDTH, KPARAM_HEIGHT, KPARAM_CNT };
static int video[KPARAM_CNT] = { 2, XENFB_WIDTH, XENFB_HEIGHT };
module_param_array(video, int, NULL, 0);
MODULE_PARM_DESC(video,
	"Video memory size in MB, width, height in pixels (default 2,800,600)");

static void xenfb_make_preferred_console(void);
static int xenfb_remove(struct xenbus_device *);
static void xenfb_init_shared_page(struct xenfb_info *, struct fb_info *);
static int xenfb_connect_backend(struct xenbus_device *, struct xenfb_info *);
static void xenfb_disconnect_backend(struct xenfb_info *);

static void xenfb_send_event(struct xenfb_info *info,
			     union xenfb_out_event *event)
{
	u32 prod;

	prod = info->page->out_prod;
	/* caller ensures !xenfb_queue_full() */
	mb();			/* ensure ring space available */
	XENFB_OUT_RING_REF(info->page, prod) = *event;
	wmb();			/* ensure ring contents visible */
	info->page->out_prod = prod + 1;

	notify_remote_via_irq(info->irq);
}

static void xenfb_do_update(struct xenfb_info *info,
			    int x, int y, int w, int h)
{
	union xenfb_out_event event;

	memset(&event, 0, sizeof(event));
	event.type = XENFB_TYPE_UPDATE;
	event.update.x = x;
	event.update.y = y;
	event.update.width = w;
	event.update.height = h;

	/* caller ensures !xenfb_queue_full() */
	xenfb_send_event(info, &event);
}

static void xenfb_do_resize(struct xenfb_info *info)
{
	union xenfb_out_event event;

	memset(&event, 0, sizeof(event));
	event.resize = info->resize;

	/* caller ensures !xenfb_queue_full() */
	xenfb_send_event(info, &event);
}

static int xenfb_queue_full(struct xenfb_info *info)
{
	u32 cons, prod;

	prod = info->page->out_prod;
	cons = info->page->out_cons;
	return prod - cons == XENFB_OUT_RING_LEN;
}

static void xenfb_handle_resize_dpy(struct xenfb_info *info)
{
	unsigned long flags;

	spin_lock_irqsave(&info->resize_lock, flags);
	if (info->resize_dpy) {
		if (!xenfb_queue_full(info)) {
			info->resize_dpy = 0;
			xenfb_do_resize(info);
		}
	}
	spin_unlock_irqrestore(&info->resize_lock, flags);
}

static void xenfb_refresh(struct xenfb_info *info,
			  int x1, int y1, int w, int h)
{
	unsigned long flags;
	int x2 = x1 + w - 1;
	int y2 = y1 + h - 1;

	xenfb_handle_resize_dpy(info);

	if (!info->update_wanted)
		return;

	spin_lock_irqsave(&info->dirty_lock, flags);

	/* Combine with dirty rectangle: */
	if (info->y1 < y1)
		y1 = info->y1;
	if (info->y2 > y2)
		y2 = info->y2;
	if (info->x1 < x1)
		x1 = info->x1;
	if (info->x2 > x2)
		x2 = info->x2;

	if (xenfb_queue_full(info)) {
		/* Can't send right now, stash it in the dirty rectangle */
		info->x1 = x1;
		info->x2 = x2;
		info->y1 = y1;
		info->y2 = y2;
		spin_unlock_irqrestore(&info->dirty_lock, flags);
		return;
	}

	/* Clear dirty rectangle: */
	info->x1 = info->y1 = INT_MAX;
	info->x2 = info->y2 = 0;

	spin_unlock_irqrestore(&info->dirty_lock, flags);

	if (x1 <= x2 && y1 <= y2)
		xenfb_do_update(info, x1, y1, x2 - x1 + 1, y2 - y1 + 1);
}

static void xenfb_deferred_io(struct fb_info *fb_info,
			      struct list_head *pagelist)
{
	struct xenfb_info *info = fb_info->par;
	struct page *page;
	unsigned long beg, end;
	int y1, y2, miny, maxy;

	miny = INT_MAX;
	maxy = 0;
	list_for_each_entry(page, pagelist, lru) {
		beg = page->index << PAGE_SHIFT;
		end = beg + PAGE_SIZE - 1;
		y1 = beg / fb_info->fix.line_length;
		y2 = end / fb_info->fix.line_length;
		if (y2 >= fb_info->var.yres)
			y2 = fb_info->var.yres - 1;
		if (miny > y1)
			miny = y1;
		if (maxy < y2)
			maxy = y2;
	}
	xenfb_refresh(info, 0, miny, fb_info->var.xres, maxy - miny + 1);
}

static struct fb_deferred_io xenfb_defio = {
	.delay		= HZ / 20,
	.deferred_io	= xenfb_deferred_io,
};

static int xenfb_setcolreg(unsigned regno, unsigned red, unsigned green,
			   unsigned blue, unsigned transp,
			   struct fb_info *info)
{
	u32 v;

	if (regno > info->cmap.len)
		return 1;

#define CNVT_TOHW(val, width) ((((val)<<(width))+0x7FFF-(val))>>16)
	red = CNVT_TOHW(red, info->var.red.length);
	green = CNVT_TOHW(green, info->var.green.length);
	blue = CNVT_TOHW(blue, info->var.blue.length);
	transp = CNVT_TOHW(transp, info->var.transp.length);
#undef CNVT_TOHW

	v = (red << info->var.red.offset) |
	    (green << info->var.green.offset) |
	    (blue << info->var.blue.offset);

	switch (info->var.bits_per_pixel) {
	case 16:
	case 24:
	case 32:
		((u32 *)info->pseudo_palette)[regno] = v;
		break;
	}

	return 0;
}

static void xenfb_fillrect(struct fb_info *p, const struct fb_fillrect *rect)
{
	struct xenfb_info *info = p->par;

	sys_fillrect(p, rect);
	xenfb_refresh(info, rect->dx, rect->dy, rect->width, rect->height);
}

static void xenfb_imageblit(struct fb_info *p, const struct fb_image *image)
{
	struct xenfb_info *info = p->par;

	sys_imageblit(p, image);
	xenfb_refresh(info, image->dx, image->dy, image->width, image->height);
}

static void xenfb_copyarea(struct fb_info *p, const struct fb_copyarea *area)
{
	struct xenfb_info *info = p->par;

	sys_copyarea(p, area);
	xenfb_refresh(info, area->dx, area->dy, area->width, area->height);
}

static ssize_t xenfb_write(struct fb_info *p, const char __user *buf,
			size_t count, loff_t *ppos)
{
	struct xenfb_info *info = p->par;
	ssize_t res;

	res = fb_sys_write(p, buf, count, ppos);
	xenfb_refresh(info, 0, 0, info->page->width, info->page->height);
	return res;
}

static int
xenfb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
{
	struct xenfb_info *xenfb_info;
	int required_mem_len;

	xenfb_info = info->par;

	if (!xenfb_info->feature_resize) {
		if (var->xres == video[KPARAM_WIDTH] &&
		    var->yres == video[KPARAM_HEIGHT] &&
		    var->bits_per_pixel == xenfb_info->page->depth) {
			return 0;
		}
		return -EINVAL;
	}

	/* Can't resize past initial width and height */
	if (var->xres > video[KPARAM_WIDTH] || var->yres > video[KPARAM_HEIGHT])
		return -EINVAL;

	required_mem_len = var->xres * var->yres * xenfb_info->page->depth / 8;
	if (var->bits_per_pixel == xenfb_info->page->depth &&
	    var->xres <= info->fix.line_length / (XENFB_DEPTH / 8) &&
	    required_mem_len <= info->fix.smem_len) {
		var->xres_virtual = var->xres;
		var->yres_virtual = var->yres;
		return 0;
	}
	return -EINVAL;
}

static int xenfb_set_par(struct fb_info *info)
{
	struct xenfb_info *xenfb_info;
	unsigned long flags;

	xenfb_info = info->par;

	spin_lock_irqsave(&xenfb_info->resize_lock, flags);
	xenfb_info->resize.type = XENFB_TYPE_RESIZE;
	xenfb_info->resize.width = info->var.xres;
	xenfb_info->resize.height = info->var.yres;
	xenfb_info->resize.stride = info->fix.line_length;
	xenfb_info->resize.depth = info->var.bits_per_pixel;
	xenfb_info->resize.offset = 0;
	xenfb_info->resize_dpy = 1;
	spin_unlock_irqrestore(&xenfb_info->resize_lock, flags);
	return 0;
}

static struct fb_ops xenfb_fb_ops = {
	.owner		= THIS_MODULE,
	.fb_read	= fb_sys_read,
	.fb_write	= xenfb_write,
	.fb_setcolreg	= xenfb_setcolreg,
	.fb_fillrect	= xenfb_fillrect,
	.fb_copyarea	= xenfb_copyarea,
	.fb_imageblit	= xenfb_imageblit,
	.fb_check_var	= xenfb_check_var,
	.fb_set_par     = xenfb_set_par,
};

static irqreturn_t xenfb_event_handler(int rq, void *dev_id)
{
	/*
	 * No in events recognized, simply ignore them all.
	 * If you need to recognize some, see xen-kbdfront's
	 * input_handler() for how to do that.
	 */
	struct xenfb_info *info = dev_id;
	struct xenfb_page *page = info->page;

	if (page->in_cons != page->in_prod) {
		info->page->in_cons = info->page->in_prod;
		notify_remote_via_irq(info->irq);
	}

	/* Flush dirty rectangle: */
	xenfb_refresh(info, INT_MAX, INT_MAX, -INT_MAX, -INT_MAX);