xen-fbfront.c

Linux环境下视频显示卡设备的驱动程序源代码

	return IRQ_HANDLED;
}

static int __devinit xenfb_probe(struct xenbus_device *dev,
				 const struct xenbus_device_id *id)
{
	struct xenfb_info *info;
	struct fb_info *fb_info;
	int fb_size;
	int val;
	int ret;

	info = kzalloc(sizeof(*info), GFP_KERNEL);
	if (info == NULL) {
		xenbus_dev_fatal(dev, -ENOMEM, "allocating info structure");
		return -ENOMEM;
	}

	/* Limit kernel param videoram amount to what is in xenstore */
	if (xenbus_scanf(XBT_NIL, dev->otherend, "videoram", "%d", &val) == 1) {
		if (val < video[KPARAM_MEM])
			video[KPARAM_MEM] = val;
	}

	/* If requested res does not fit in available memory, use default */
	fb_size = video[KPARAM_MEM] * 1024 * 1024;
	if (video[KPARAM_WIDTH] * video[KPARAM_HEIGHT] * XENFB_DEPTH / 8
	    > fb_size) {
		video[KPARAM_WIDTH] = XENFB_WIDTH;
		video[KPARAM_HEIGHT] = XENFB_HEIGHT;
		fb_size = XENFB_DEFAULT_FB_LEN;
	}

	dev->dev.driver_data = info;
	info->xbdev = dev;
	info->irq = -1;
	info->x1 = info->y1 = INT_MAX;
	spin_lock_init(&info->dirty_lock);
	spin_lock_init(&info->resize_lock);

	info->fb = vmalloc(fb_size);
	if (info->fb == NULL)
		goto error_nomem;
	memset(info->fb, 0, fb_size);

	info->nr_pages = (fb_size + PAGE_SIZE - 1) >> PAGE_SHIFT;

	info->mfns = vmalloc(sizeof(unsigned long) * info->nr_pages);
	if (!info->mfns)
		goto error_nomem;

	/* set up shared page */
	info->page = (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
	if (!info->page)
		goto error_nomem;

	/* abusing framebuffer_alloc() to allocate pseudo_palette */
	fb_info = framebuffer_alloc(sizeof(u32) * 256, NULL);
	if (fb_info == NULL)
		goto error_nomem;

	/* complete the abuse: */
	fb_info->pseudo_palette = fb_info->par;
	fb_info->par = info;

	fb_info->screen_base = info->fb;

	fb_info->fbops = &xenfb_fb_ops;
	fb_info->var.xres_virtual = fb_info->var.xres = video[KPARAM_WIDTH];
	fb_info->var.yres_virtual = fb_info->var.yres = video[KPARAM_HEIGHT];
	fb_info->var.bits_per_pixel = XENFB_DEPTH;

	fb_info->var.red = (struct fb_bitfield){16, 8, 0};
	fb_info->var.green = (struct fb_bitfield){8, 8, 0};
	fb_info->var.blue = (struct fb_bitfield){0, 8, 0};

	fb_info->var.activate = FB_ACTIVATE_NOW;
	fb_info->var.height = -1;
	fb_info->var.width = -1;
	fb_info->var.vmode = FB_VMODE_NONINTERLACED;

	fb_info->fix.visual = FB_VISUAL_TRUECOLOR;
	fb_info->fix.line_length = fb_info->var.xres * XENFB_DEPTH / 8;
	fb_info->fix.smem_start = 0;
	fb_info->fix.smem_len = fb_size;
	strcpy(fb_info->fix.id, "xen");
	fb_info->fix.type = FB_TYPE_PACKED_PIXELS;
	fb_info->fix.accel = FB_ACCEL_NONE;

	fb_info->flags = FBINFO_FLAG_DEFAULT;

	ret = fb_alloc_cmap(&fb_info->cmap, 256, 0);
	if (ret < 0) {
		framebuffer_release(fb_info);
		xenbus_dev_fatal(dev, ret, "fb_alloc_cmap");
		goto error;
	}

	fb_info->fbdefio = &xenfb_defio;
	fb_deferred_io_init(fb_info);

	xenfb_init_shared_page(info, fb_info);

	ret = register_framebuffer(fb_info);
	if (ret) {
		fb_deferred_io_cleanup(fb_info);
		fb_dealloc_cmap(&fb_info->cmap);
		framebuffer_release(fb_info);
		xenbus_dev_fatal(dev, ret, "register_framebuffer");
		goto error;
	}
	info->fb_info = fb_info;

	ret = xenfb_connect_backend(dev, info);
	if (ret < 0)
		goto error;

	xenfb_make_preferred_console();
	return 0;

 error_nomem:
	ret = -ENOMEM;
	xenbus_dev_fatal(dev, ret, "allocating device memory");
 error:
	xenfb_remove(dev);
	return ret;
}

static __devinit void
xenfb_make_preferred_console(void)
{
	struct console *c;

	if (console_set_on_cmdline)
		return;

	acquire_console_sem();
	for (c = console_drivers; c; c = c->next) {
		if (!strcmp(c->name, "tty") && c->index == 0)
			break;
	}
	release_console_sem();
	if (c) {
		unregister_console(c);
		c->flags |= CON_CONSDEV;
		c->flags &= ~CON_PRINTBUFFER; /* don't print again */
		register_console(c);
	}
}

static int xenfb_resume(struct xenbus_device *dev)
{
	struct xenfb_info *info = dev->dev.driver_data;

	xenfb_disconnect_backend(info);
	xenfb_init_shared_page(info, info->fb_info);
	return xenfb_connect_backend(dev, info);
}

static int xenfb_remove(struct xenbus_device *dev)
{
	struct xenfb_info *info = dev->dev.driver_data;

	xenfb_disconnect_backend(info);
	if (info->fb_info) {
		fb_deferred_io_cleanup(info->fb_info);
		unregister_framebuffer(info->fb_info);
		fb_dealloc_cmap(&info->fb_info->cmap);
		framebuffer_release(info->fb_info);
	}
	free_page((unsigned long)info->page);
	vfree(info->mfns);
	vfree(info->fb);
	kfree(info);

	return 0;
}

static unsigned long vmalloc_to_mfn(void *address)
{
	return pfn_to_mfn(vmalloc_to_pfn(address));
}

static void xenfb_init_shared_page(struct xenfb_info *info,
				   struct fb_info *fb_info)
{
	int i;
	int epd = PAGE_SIZE / sizeof(info->mfns[0]);

	for (i = 0; i < info->nr_pages; i++)
		info->mfns[i] = vmalloc_to_mfn(info->fb + i * PAGE_SIZE);

	for (i = 0; i * epd < info->nr_pages; i++)
		info->page->pd[i] = vmalloc_to_mfn(&info->mfns[i * epd]);

	info->page->width = fb_info->var.xres;
	info->page->height = fb_info->var.yres;
	info->page->depth = fb_info->var.bits_per_pixel;
	info->page->line_length = fb_info->fix.line_length;
	info->page->mem_length = fb_info->fix.smem_len;
	info->page->in_cons = info->page->in_prod = 0;
	info->page->out_cons = info->page->out_prod = 0;
}

static int xenfb_connect_backend(struct xenbus_device *dev,
				 struct xenfb_info *info)
{
	int ret, evtchn;
	struct xenbus_transaction xbt;

	ret = xenbus_alloc_evtchn(dev, &evtchn);
	if (ret)
		return ret;
	ret = bind_evtchn_to_irqhandler(evtchn, xenfb_event_handler,
					0, dev->devicetype, info);
	if (ret < 0) {
		xenbus_free_evtchn(dev, evtchn);
		xenbus_dev_fatal(dev, ret, "bind_evtchn_to_irqhandler");
		return ret;
	}
	info->irq = ret;

 again:
	ret = xenbus_transaction_start(&xbt);
	if (ret) {
		xenbus_dev_fatal(dev, ret, "starting transaction");
		return ret;
	}
	ret = xenbus_printf(xbt, dev->nodename, "page-ref", "%lu",
			    virt_to_mfn(info->page));
	if (ret)
		goto error_xenbus;
	ret = xenbus_printf(xbt, dev->nodename, "event-channel", "%u",
			    evtchn);
	if (ret)
		goto error_xenbus;
	ret = xenbus_printf(xbt, dev->nodename, "protocol", "%s",
			    XEN_IO_PROTO_ABI_NATIVE);
	if (ret)
		goto error_xenbus;
	ret = xenbus_printf(xbt, dev->nodename, "feature-update", "1");
	if (ret)
		goto error_xenbus;
	ret = xenbus_transaction_end(xbt, 0);
	if (ret) {
		if (ret == -EAGAIN)
			goto again;
		xenbus_dev_fatal(dev, ret, "completing transaction");
		return ret;
	}

	xenbus_switch_state(dev, XenbusStateInitialised);
	return 0;

 error_xenbus:
	xenbus_transaction_end(xbt, 1);
	xenbus_dev_fatal(dev, ret, "writing xenstore");
	return ret;
}

static void xenfb_disconnect_backend(struct xenfb_info *info)
{
	if (info->irq >= 0)
		unbind_from_irqhandler(info->irq, info);
	info->irq = -1;
}

static void xenfb_backend_changed(struct xenbus_device *dev,
				  enum xenbus_state backend_state)
{
	struct xenfb_info *info = dev->dev.driver_data;
	int val;

	switch (backend_state) {
	case XenbusStateInitialising:
	case XenbusStateInitialised:
	case XenbusStateUnknown:
	case XenbusStateClosed:
		break;

	case XenbusStateInitWait:
InitWait:
		xenbus_switch_state(dev, XenbusStateConnected);
		break;

	case XenbusStateConnected:
		/*
		 * Work around xenbus race condition: If backend goes
		 * through InitWait to Connected fast enough, we can
		 * get Connected twice here.
		 */
		if (dev->state != XenbusStateConnected)
			goto InitWait; /* no InitWait seen yet, fudge it */

		if (xenbus_scanf(XBT_NIL, info->xbdev->otherend,
				 "request-update", "%d", &val) < 0)
			val = 0;
		if (val)
			info->update_wanted = 1;

		if (xenbus_scanf(XBT_NIL, dev->otherend,
				 "feature-resize", "%d", &val) < 0)
			val = 0;
		info->feature_resize = val;
		break;

	case XenbusStateClosing:
		xenbus_frontend_closed(dev);
		break;
	}
}

static struct xenbus_device_id xenfb_ids[] = {
	{ "vfb" },
	{ "" }
};

static struct xenbus_driver xenfb_driver = {
	.name = "vfb",
	.owner = THIS_MODULE,
	.ids = xenfb_ids,
	.probe = xenfb_probe,
	.remove = xenfb_remove,
	.resume = xenfb_resume,
	.otherend_changed = xenfb_backend_changed,
};

static int __init xenfb_init(void)
{
	if (!xen_domain())
		return -ENODEV;

	/* Nothing to do if running in dom0. */
	if (xen_initial_domain())
		return -ENODEV;

	return xenbus_register_frontend(&xenfb_driver);
}

static void __exit xenfb_cleanup(void)
{
	xenbus_unregister_driver(&xenfb_driver);
}

module_init(xenfb_init);
module_exit(xenfb_cleanup);

MODULE_DESCRIPTION("Xen virtual framebuffer device frontend");
MODULE_LICENSE("GPL");
MODULE_ALIAS("xen:vfb");