s3c6410_LCD & frame buffer 驱动分析(二)

/*
 *初始化LCD控制寄存器
 */

int s3cfb_init_registers(s3cfb_info_t *fbi)

{
    struct clk *lcd_clock;
    struct fb_var_screeninfo *var = &fbi->fb.var;
    unsigned long flags = 0, page_width = 0, offset = 0;
    unsigned long video_phy_temp_f1 = fbi->screen_dma_f1;//物理地址
    unsigned long video_phy_temp_f2 = fbi->screen_dma_f2;//物理地址
    int win_num =  fbi->win_id;//5个窗口
//关闭中断在写LCD控制寄存器之前,并保存中断状态
    local_irq_save(flags);
//显示宽度,以字节为单位
    page_width = var->xres * s3cfb_fimd.bytes_per_pixel;
//虚拟到可见区域的偏移量,以字节为单位
    offset = (var->xres_virtual - var->xres) * s3cfb_fimd.bytes_per_pixel;
    if (win_num == 0) {
//在配置LCD控制器之前需要先关闭LCD视频输出
        s3cfb_fimd.vidcon0 = s3cfb_fimd.vidcon0 & ~(S3C_VIDCON0_ENVID_ENABLE | S3C_VIDCON0_ENVID_F_ENABLE);
        writel(s3cfb_fimd.vidcon0, S3C_VIDCON0);
//获取LCD时钟来源 Video Clock Source is selected by CLKSEL_F registe
        lcd_clock = clk_get(NULL, "lcd");
//计算VCLK = lcd_clock / (CLKVAL+1)
        s3cfb_fimd.vidcon0 |= S3C_VIDCON0_CLKVAL_F((int) ((clk_get_rate(lcd_clock) / s3cfb_fimd.pixclock) - 1));
#if defined(CONFIG_FB_S3C_EXT_VIRTUAL_SCREEN)
        offset = 0;//将虚拟到可见区域的偏移量设置成0
//Window 0’s buffer start address register, buffer 0
        s3cfb_fimd.vidw00add0b0 = video_phy_temp_f1;
//Window 0’s buffer start address register, buffer 1
        s3cfb_fimd.vidw00add0b1 = video_phy_temp_f2;
 //Window 1’s buffer start address register, buffer 0
        s3cfb_fimd.vidw00add1b0 = S3C_VIDWxxADD1_VBASEL_F((unsigned long) video_phy_temp_f1 + (page_width + offset) * (var->yres));
//Window 1’s buffer start address register, buffer 1
        s3cfb_fimd.vidw00add1b1 = S3C_VIDWxxADD1_VBASEL_F((unsigned long) video_phy_temp_f2 + (page_width + offset) * (var->yres));
#endif
     }
//各窗口起始地址
    writel(video_phy_temp_f1, S3C_VIDW00ADD0B0 + (0x08 * win_num));
//各窗口结束地址
    writel(S3C_VIDWxxADD1_VBASEL_F((unsigned long) video_phy_temp_f1 + (page_width + offset) * (var->yres)), S3C_VIDW00ADD1B0 + (0x08 * win_num));
// Virtual screen offset size (the number of byte).
    writel(S3C_VIDWxxADD2_OFFSIZE_F(offset) | (S3C_VIDWxxADD2_PAGEWIDTH_F(page_width)), S3C_VIDW00ADD2 + (0x04 * win_num));

    if (win_num < 2) {
        writel(video_phy_temp_f2, S3C_VIDW00ADD0B1 + (0x08 * win_num));
        writel(S3C_VIDWxxADD1_VBASEL_F((unsigned long) video_phy_temp_f2 + (page_width + offset) * (var->yres)), S3C_VIDW00ADD1B1 + (0x08 * win_num));
    }
//上面这些操作可以对照S3C6410手册照着填写
    switch (win_num) {
//将配置好的值都写入个寄存器当中
    case 0:
        writel(s3cfb_fimd.wincon0, S3C_WINCON0);
        writel(s3cfb_fimd.vidcon0, S3C_VIDCON0);
        writel(s3cfb_fimd.vidcon1, S3C_VIDCON1);
        writel(s3cfb_fimd.vidtcon0, S3C_VIDTCON0);
        writel(s3cfb_fimd.vidtcon1, S3C_VIDTCON1);
        writel(s3cfb_fimd.vidtcon2, S3C_VIDTCON2);
        writel(s3cfb_fimd.dithmode, S3C_DITHMODE);
        writel(s3cfb_fimd.vidintcon0, S3C_VIDINTCON0);
        writel(s3cfb_fimd.vidintcon1, S3C_VIDINTCON1);
        writel(s3cfb_fimd.vidosd0a, S3C_VIDOSD0A);
        writel(s3cfb_fimd.vidosd0b, S3C_VIDOSD0B);
        writel(s3cfb_fimd.vidosd0c, S3C_VIDOSD0C);
        writel(s3cfb_fimd.wpalcon, S3C_WPALCON);

        s3cfb_onoff_win(fbi, ON);
        break;

    case 1:
        writel(s3cfb_fimd.wincon1, S3C_WINCON1);
        writel(s3cfb_fimd.vidosd1a, S3C_VIDOSD1A);
        writel(s3cfb_fimd.vidosd1b, S3C_VIDOSD1B);
        writel(s3cfb_fimd.vidosd1c, S3C_VIDOSD1C);
        writel(s3cfb_fimd.vidosd1d, S3C_VIDOSD1D);
        writel(s3cfb_fimd.wpalcon, S3C_WPALCON);
        s3cfb_onoff_win(fbi, OFF);
        break;
    case 2:
        writel(s3cfb_fimd.wincon2, S3C_WINCON2);
        writel(s3cfb_fimd.vidosd2a, S3C_VIDOSD2A);
        writel(s3cfb_fimd.vidosd2b, S3C_VIDOSD2B);
        writel(s3cfb_fimd.vidosd2c, S3C_VIDOSD2C);
        writel(s3cfb_fimd.vidosd2d, S3C_VIDOSD2D);
        writel(s3cfb_fimd.wpalcon, S3C_WPALCON);
        s3cfb_onoff_win(fbi, OFF);
        break;
    case 3:
        writel(s3cfb_fimd.wincon3, S3C_WINCON3);
        writel(s3cfb_fimd.vidosd3a, S3C_VIDOSD3A);
        writel(s3cfb_fimd.vidosd3b, S3C_VIDOSD3B);
        writel(s3cfb_fimd.vidosd3c, S3C_VIDOSD3C);
        writel(s3cfb_fimd.wpalcon, S3C_WPALCON);
        s3cfb_onoff_win(fbi, OFF);
        break;
    case 4:
        writel(s3cfb_fimd.wincon4, S3C_WINCON4);
        writel(s3cfb_fimd.vidosd4a, S3C_VIDOSD4A);
        writel(s3cfb_fimd.vidosd4b, S3C_VIDOSD4B);
        writel(s3cfb_fimd.vidosd4c, S3C_VIDOSD4C);
        writel(s3cfb_fimd.wpalcon, S3C_WPALCON);
        s3cfb_onoff_win(fbi, OFF);
        break;
    }
//开启中断
    local_irq_restore(flags);
    return 0;
 }

//下面可以分析framebuffer提供给应用层的函数操作指针了

struct fb_ops s3cfb_ops = {
    .owner        = THIS_MODULE,
    .fb_check_var    = s3cfb_check_var,//检测可变参数,并调整到支持的值
    .fb_set_par    = s3cfb_set_par,      //设置video的模式
    .fb_blank    = s3cfb_blank,              //显示空白区域
    .fb_pan_display    = s3cfb_pan_display,//pan显示
    .fb_setcolreg    = s3cfb_setcolreg,//设置color寄存器,设置颜色表
    .fb_fillrect    = cfb_fillrect,        //矩形填充
    .fb_copyarea    = cfb_copyarea,    //数据复制
    .fb_imageblit    = cfb_imageblit,  //图形填充
    .fb_cursor    = soft_cursor,       //绘制光标
    .fb_ioctl    = s3cfb_ioctl,         //fb特定的ioctl
};

这里只贴s3cfb_ioctl的代码,其余的详情可以参见Linux内核源代码,另外值得注意的就是这些函数都可以使用默认内核默认的,fbmem.c中

int s3cfb_ioctl(struct fb_info *info, unsigned int cmd, unsigned long arg)
{
    s3cfb_info_t *fbi = container_of(info, s3cfb_info_t, fb);
    s3cfb_win_info_t win_info;
    s3cfb_color_key_info_t colkey_info;
    s3cfb_color_val_info_t colval_info;
    s3cfb_dma_info_t dma_info;
    s3cfb_next_info_t next_fb_info;
    struct fb_var_screeninfo *var= &fbi->fb.var;
    unsigned int crt, alpha_level, alpha_mode;
#if defined(CONFIG_S3C6410_PWM)
    int brightness;
#endif
#if defined(CONFIG_FB_S3C_EXT_DOUBLE_BUFFERING)
    unsigned int f_num_val;
#endif
#if defined(CONFIG_FB_S3C_EXT_VIRTUAL_SCREEN)
    s3cfb_vs_info_t vs_info;
#endif
    switch(cmd){
    case S3CFB_GET_INFO:
        dma_info.map_dma_f1 = fbi->map_dma_f1;
        dma_info.map_dma_f2 = fbi->map_dma_f2;
        if(copy_to_user((void *) arg, (const void *) &dma_info, sizeof(s3cfb_dma_info_t)))
            return -EFAULT;
        break;
    case S3CFB_OSD_SET_INFO:
        if (copy_from_user(&win_info, (s3cfb_win_info_t *) arg, sizeof(s3cfb_win_info_t)))
            return -EFAULT;
        s3cfb_init_win(fbi, win_info.bpp, win_info.left_x, win_info.top_y, win_info.width, win_info.height, OFF);
        break;
    case S3CFB_OSD_START:
        s3cfb_onoff_win(fbi, ON);
        break;
    case S3CFB_OSD_STOP:
        s3cfb_onoff_win(fbi, OFF);
        break;
    case S3CFB_OSD_ALPHA_UP:
        alpha_level = readl(S3C_VIDOSD0C + (0x10 * fbi->win_id)) & 0xf;
        if (alpha_level < S3CFB_MAX_ALPHA_LEVEL)
            alpha_level++;
        s3cfb_set_alpha_level(fbi, alpha_level, 1);
        break;
    case S3CFB_OSD_ALPHA_DOWN:
        alpha_level = readl(S3C_VIDOSD0C + (0x10 * fbi->win_id)) & 0xf;
        if (alpha_level > 0)
            alpha_level--;
        s3cfb_set_alpha_level(fbi, alpha_level, 1);
        break;
    case S3CFB_OSD_ALPHA0_SET:
        alpha_level = (unsigned int) arg;
        if (alpha_level > S3CFB_MAX_ALPHA_LEVEL)
            alpha_level = S3CFB_MAX_ALPHA_LEVEL;
        s3cfb_set_alpha_level(fbi, alpha_level, 0);
        break;
    case S3CFB_OSD_ALPHA1_SET:
        alpha_level = (unsigned int) arg;
        if (alpha_level > S3CFB_MAX_ALPHA_LEVEL)
            alpha_level = S3CFB_MAX_ALPHA_LEVEL;
        s3cfb_set_alpha_level(fbi, alpha_level, 1);
        break;
    case S3CFB_OSD_ALPHA_MODE:
        alpha_mode = (unsigned int) arg;
        s3cfb_set_alpha_mode(fbi, alpha_mode);
        break;
    case S3CFB_OSD_MOVE_LEFT:
        if (var->xoffset > 0)
            var->xoffset--;
        s3cfb_set_win_position(fbi, var->xoffset, var->yoffset, var->xres, var->yres);
        break;
    case S3CFB_OSD_MOVE_RIGHT:
        if (var->xoffset < (s3cfb_fimd.width - var->xres))
            var->xoffset++;
        s3cfb_set_win_position(fbi, var->xoffset, var->yoffset, var->xres, var->yres);
        break;
    case S3CFB_OSD_MOVE_UP:
        if (var->yoffset > 0)
            var->yoffset--;
        s3cfb_set_win_position(fbi, var->xoffset, var->yoffset, var->xres, var->yres);
        break;
    case S3CFB_OSD_MOVE_DOWN:
        if (var->yoffset < (s3cfb_fimd.height - var->yres))
            var->yoffset++;
        s3cfb_set_win_position(fbi, var->xoffset, var->yoffset, var->xres, var->yres);
        break;
    case FBIO_WAITFORVSYNC:
        if (get_user(crt, (unsigned int __user *)arg))
            return -EFAULT;
        return s3cfb_wait_for_vsync();
    case S3CFB_COLOR_KEY_START:
        s3cfb_onoff_color_key(fbi, ON);
        break;
    case S3CFB_COLOR_KEY_STOP:
        s3cfb_onoff_color_key(fbi, OFF);
        break;
    case S3CFB_COLOR_KEY_ALPHA_START:
        s3cfb_onoff_color_key_alpha(fbi, ON);
        break;
    case S3CFB_COLOR_KEY_ALPHA_STOP:
        s3cfb_onoff_color_key_alpha(fbi, OFF);
        break;
    case S3CFB_COLOR_KEY_SET_INFO:
        if (copy_from_user(&colkey_info, (s3cfb_color_key_info_t *) arg, sizeof(s3cfb_color_key_info_t)))
            return -EFAULT;
        s3cfb_set_color_key_registers(fbi, colkey_info);
        break;
    case S3CFB_COLOR_KEY_VALUE:
        if (copy_from_user(&colval_info, (s3cfb_color_val_info_t *) arg, sizeof(s3cfb_color_val_info_t)))
            return -EFAULT;
        s3cfb_set_color_value(fbi, colval_info);
        break;
    case S3CFB_SET_VSYNC_INT:
        s3cfb_fimd.vidintcon0 &= ~S3C_VIDINTCON0_FRAMESEL0_MASK;
        s3cfb_fimd.vidintcon0 |= S3C_VIDINTCON0_FRAMESEL0_VSYNC;
        if (arg)
            s3cfb_fimd.vidintcon0 |= S3C_VIDINTCON0_INTFRMEN_ENABLE;
        else
            s3cfb_fimd.vidintcon0 &= ~S3C_VIDINTCON0_INTFRMEN_ENABLE;
        writel(s3cfb_fimd.vidintcon0, S3C_VIDINTCON0);
        break;
    case S3CFB_SET_NEXT_FB_INFO:
        if (copy_from_user(&next_fb_info, (s3cfb_next_info_t *) arg, sizeof(s3cfb_next_info_t)))
            return -EFAULT;
        /* check arguments */
        if ((next_fb_info.xres + next_fb_info.xoffset) > next_fb_info.xres_virtual ||
            (next_fb_info.yres + next_fb_info.yoffset) > next_fb_info.yres_virtual ||
            (next_fb_info.xres + next_fb_info.lcd_offset_x ) > s3cfb_fimd.width ||
            (next_fb_info.yres + next_fb_info.lcd_offset_y ) > s3cfb_fimd.height) {
            printk("Error : S3CFB_SET_NEXT_FB_INFO\n");
             return -EINVAL;
        }
        fbi->next_fb_info = next_fb_info;
        fbi->next_fb_info_change_req = 1;
        break;
    case S3CFB_GET_CURR_FB_INFO:
        next_fb_info.phy_start_addr = fbi->fb.fix.smem_start;
        next_fb_info.xres = fbi->fb.var.xres;
        next_fb_info.yres = fbi->fb.var.yres;
        next_fb_info.xres_virtual = fbi->fb.var.xres_virtual;
        next_fb_info.yres_virtual = fbi->fb.var.yres_virtual;
        next_fb_info.xoffset = fbi->fb.var.xoffset;
        next_fb_info.yoffset = fbi->fb.var.yoffset;
        next_fb_info.lcd_offset_x = fbi->lcd_offset_x;
        next_fb_info.lcd_offset_y = fbi->lcd_offset_y;
        if (copy_to_user((void *)arg, (s3cfb_next_info_t *) &next_fb_info, sizeof(s3cfb_next_info_t)))
            return -EFAULT;
        break;
    case S3CFB_GET_BRIGHTNESS:
        if (copy_to_user((void *)arg, (const void *) &s3cfb_fimd.brightness, sizeof(int)))
            return -EFAULT;
        break;
#if defined(CONFIG_S3C6410_PWM)
    case S3CFB_SET_BRIGHTNESS:
        if (copy_from_user(&brightness, (int *) arg, sizeof(int)))
            return -EFAULT;

        s3cfb_set_brightness(brightness);
        break;
#endif
#if defined(CONFIG_FB_S3C_EXT_VIRTUAL_SCREEN)
    case S3CFB_VS_START:
        s3cfb_fimd.wincon0 &= ~(S3C_WINCONx_ENWIN_F_ENABLE);
        writel(s3cfb_fimd.wincon0 | S3C_WINCONx_ENWIN_F_ENABLE, S3C_WINCON0);

        fbi->fb.var.xoffset = s3cfb_fimd.xoffset;
        fbi->fb.var.yoffset = s3cfb_fimd.yoffset;
        break;
    case S3CFB_VS_STOP:
        s3cfb_fimd.vidw00add0b0 = fbi->screen_dma_f1;
        s3cfb_fimd.vidw00add0b1 = fbi->screen_dma_f2;
        fbi->fb.var.xoffset = 0;
        fbi->fb.var.yoffset = 0;
        writel(s3cfb_fimd.vidw00add0b0, S3C_VIDW00ADD0B0);
        writel(s3cfb_fimd.vidw00add0b1, S3C_VIDW00ADD0B1);
        break;
    case S3CFB_VS_SET_INFO:
        if (copy_from_user(&vs_info, (s3cfb_vs_info_t *) arg, sizeof(s3cfb_vs_info_t)))
            return -EFAULT;

        if (s3cfb_set_vs_info(vs_info)) {
            printk("Error S3CFB_VS_SET_INFO\n");
            return -EINVAL;
        }
        s3cfb_set_vs_registers(S3CFB_VS_SET);
        fbi->fb.var.xoffset = s3cfb_fimd.xoffset;
        fbi->fb.var.yoffset = s3cfb_fimd.yoffset;
        break;
    case S3CFB_VS_MOVE:
        s3cfb_set_vs_registers(arg);

        fbi->fb.var.xoffset = s3cfb_fimd.xoffset;
        fbi->fb.var.yoffset = s3cfb_fimd.yoffset;
        break;
#endif
#if defined(CONFIG_FB_S3C_EXT_DOUBLE_BUFFERING)
    case S3CFB_GET_NUM:
        if (copy_from_user((void *)&f_num_val, (const void *)arg, sizeof(u_int)))
            return -EFAULT;
        if (copy_to_user((void *)arg, (const void *) &f_num_val, sizeof(u_int)))
            return -EFAULT;
        break;
    case S3CFB_CHANGE_REQ:
        s3cfb_change_buff(0, (int) arg);
        break;
#endif

    default:
        return -EINVAL;
    }
    return 0;
}

关于IOCTL中的命令的定义以及各命令当中的处理函数可以下载LCD驱动源码连接点击下载LCD驱动源码 这些命令都定义在s3cfb.h当中,另外值得注意的就是linux内核当中

提供给framebuffer的通用代码fbmem.c中的ioctl函数。当我们真正拿LCD来显示一些什么东西的时候那么熟悉这些ioctl函数是很有必要的,至少做的时候要值得在那个地方找