s5pv210 android hdmi与LCD异步显示之fb2多线程操作驱动修改

川长思鸟来 2022-08-07 13:57 133阅读 0赞

之前有一篇文章已经介绍过210 linux hdmi显示 android和处理现在是把系统自带的hdmi相关代码删除 使用之前linux上用到的hdmi代码显示输出 改为由fb2同步显示到hdmi 内核版本linux3.0.8

一般情况能进行多线程操作的只有fb0设备　虽然dev下有显示fb1-4的设备但不能多个线程进行操作 如果某一个线程需要对fb1-4进行操作需要在应用程序中加上如下代码

ret = ioctl(lcd_fd, FBIOGET_VSCREENINFO, &var );
    	if( ret < 0 ){
    		printf( "ioctl FBIOGET_VSCREENINFO failed\n");
    		return -1;
    	}
    	var.activate = FB_ACTIVATE_FORCE;
    	var.yres_virtual = var.yres;
    
    	ret = ioctl(lcd_fd, FBIOPUT_VSCREENINFO, &var );
    	if( ret < 0 ){
    		printf( "ioctl FBIOPUT_VSCREENINFO failed\n");
    		return -1;
    	}

每这样操作一次　就会导致对应的frambuffer地址发生变化　同时其它进程也会mmap失败　这里就需要对fb驱动作进行修改

主要修改文件为

drivers/video/samsung/s3cfb.c

首先是

s3cfb\_alloc\_framebuffer函数里只对default\_win分配了framebuffer地址 修改为如下

#if 0 //modify by hclydao
    		if (i == pdata->default_win) {
    			if (s3cfb_map_video_memory(ctrl->fb[i])) {
    				dev_err(ctrl->dev,
    					"failed to map video memory "
    					"for default window (%d)\n", i);
    				ret = -ENOMEM;
    				goto err_map_video_mem;
    			}
    		}
    #else
    			if (s3cfb_map_video_memory(ctrl->fb[i])) {
    				dev_err(ctrl->dev,
    					"failed to map video memory "
    					"for default window (%d)\n", i);
    				ret = -ENOMEM;
    				goto err_map_video_mem;
    			}
    #endif

s3cfb\_set\_par函数修改如下

static int s3cfb_set_par(struct fb_info *fb)
    {
    	struct s3cfb_global *fbdev =
    		platform_get_drvdata(to_platform_device(fb->device));
    	struct s3c_platform_fb *pdata = to_fb_plat(fbdev->dev);
    	struct s3cfb_window *win = fb->par;
    
    	dev_dbg(fbdev->dev, "[fb%d] set_par\n", win->id);
    #if 0 //modify by hclydao
    	/* modify the fix info */
    	if (win->id != pdata->default_win) {
    		fb->fix.line_length = fb->var.xres_virtual *
    						fb->var.bits_per_pixel / 8;
    		fb->fix.smem_len = fb->fix.line_length * fb->var.yres_virtual;
    
    		s3cfb_map_video_memory(fb);
    	}
    #endif
    	s3cfb_set_win_params(fbdev, win->id);
    
    	return 0;
    }

s3cfb\_open及s3cfb\_release\_window函数修改如下

static int s3cfb_open(struct fb_info *fb, int user)
    {
    	struct s3cfb_global *fbdev =
    		platform_get_drvdata(to_platform_device(fb->device));
    	struct s3c_platform_fb *pdata = to_fb_plat(fbdev->dev);
    	struct s3cfb_window *win = fb->par;
    	int ret = 0;
    
    	mutex_lock(&fbdev->lock);
    	//modify by hclydao
    	//if (win->in_use && win->id != pdata->default_win)
    	if (win->in_use && (win->id != pdata->default_win) && (win->id != 4))
    		ret = -EBUSY;
    	else
    		win->in_use++;
    
    	mutex_unlock(&fbdev->lock);
    
    	return ret;
    }
    static int s3cfb_release_window(struct fb_info *fb)
    {
    	struct s3cfb_global *fbdev =
    		platform_get_drvdata(to_platform_device(fb->device));
    	struct s3c_platform_fb *pdata = to_fb_plat(fbdev->dev);
    	struct s3cfb_window *win = fb->par;
    	//modify by hclydao
    	//if (win->id != pdata->default_win)
    	if ((win->id != pdata->default_win) && (win->id != 4)) {
    		s3cfb_set_window(fbdev, win->id, 0);
    		s3cfb_unmap_video_memory(fb);
    		s3cfb_set_buffer_address(fbdev, win->id);
    	}
    
    	win->x = 0;
    	win->y = 0;
    
    	return 0;
    }

因为我想用多个线程对fb2进行操作　而默认的default\_win是2所以修改为如上

s3cfb\_ioctl函数中case S3CFB\_GET\_LCD\_ADDR:修改如下

/* get changing physical framebuffer address(because of double buffering) */
    	case S3CFB_GET_LCD_ADDR:
    #if 0 //modify by hclydao
    		LCDControllerBase = (volatile unsigned int *)ioremap(0xf8000000,1024);
    		framebuffer_addr = LCDControllerBase[0xa0/4 + (win->id)*2];
    		//LCDControllerBase = (volatile unsigned int *)ioremap(0xf80000a0,1024);
    		//framebuffer_addr = LCDControllerBase[(win->id)*2];
    		iounmap(LCDControllerBase);
    		dev_dbg(fbdev->dev, "framebuffer_addr: 0x%08x\n", framebuffer_addr);
    #else
    		framebuffer_addr = (int)fix->smem_start;
    		dev_dbg(fbdev->dev, "framebuffer_addr: 0x%08x\n", framebuffer_addr);
    #endif
    		if (copy_to_user((void *)arg, &framebuffer_addr, sizeof(int)))
    			return -EFAULT;
    
    		break;

s3cfb\_probe函数中加一句

s3cfb_set_window(fbdev, pdata->default_win, 1);
        //add by hclydao
        s3cfb_set_window(fbdev, 4, 1);

其中还有一些细节没有修改　可能存在bug 这样修改后就能够通过多个线程对fb2进行操作了 这里暂时只作下笔记.

目前已经实现了hdmi与lcd的异步显示 可以通过app控制hdmi输出的图片 暂时只能显示固定图片

============================================  
作者：hclydao  
[http://blog.csdn.net/hclydao][http_blog.csdn.net_hclydao]  
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