Linux内核的framebuffer相关的内核代码注释

由于现在正在进行framebuffer的一个项目开发，所以需要学习framebuffer的内核代码，今天现在这里上传我的相关注释，后面再将我的学习内容和相关framebuffer的操作提交上来．

位置：源代码根目录/include/linux/fb.h

#ifndef _LINUX_FB_H
#define _LINUX_FB_H

#include <linux/types.h>
#include <linux/i2c.h>

struct dentry;

/* Definitions of frame buffers frame buffer的定义 */

#define FB_MAX 32 /* sufficient for now 　对于现在来说足够了　*/

/* ioctls 0x46 is 'F' */
#define FBIOGET_VSCREENINFO 0x4600
#define FBIOPUT_VSCREENINFO 0x4601
#define FBIOGET_FSCREENINFO 0x4602
#define FBIOGETCMAP 0x4604
#define FBIOPUTCMAP 0x4605
#define FBIOPAN_DISPLAY 0x4606
#ifdef __KERNEL__
#define FBIO_CURSOR _IOWR('F', 0x08, struct fb_cursor_user)
#else
#define FBIO_CURSOR _IOWR('F', 0x08, struct fb_cursor)
#endif
/* 0x4607-0x460B are defined below */
/* #define FBIOGET_MONITORSPEC 0x460C */
/* #define FBIOPUT_MONITORSPEC 0x460D */
/* #define FBIOSWITCH_MONIBIT 0x460E */
#define FBIOGET_CON2FBMAP 0x460F
#define FBIOPUT_CON2FBMAP 0x4610
#define FBIOBLANK 0x4611 /* arg: 0 or vesa level + 1 */
#define FBIOGET_VBLANK _IOR('F', 0x12, struct fb_vblank)
#define FBIO_ALLOC 0x4613
#define FBIO_FREE 0x4614
#define FBIOGET_GLYPH 0x4615
#define FBIOGET_HWCINFO 0x4616
#define FBIOPUT_MODEINFO 0x4617
#define FBIOGET_DISPINFO 0x4618


#define FB_TYPE_PACKED_PIXELS 0 /* Packed Pixels 填充的像素　*/
#define FB_TYPE_PLANES 1 /* Non interleaved planes 非交错平面　*/
#define FB_TYPE_INTERLEAVED_PLANES 2 /* Interleaved planes　交错的平面　*/
#define FB_TYPE_TEXT 3 /* Text/attributes　文本/属性　*/
#define FB_TYPE_VGA_PLANES 4 /* EGA/VGA planes EGA/VGA　平面　*/

#define FB_AUX_TEXT_MDA 0 /* Monochrome text 单色文本　*/
#define FB_AUX_TEXT_CGA 1 /* CGA/EGA/VGA Color text CGA/EGA/VGA色彩文本　*/
#define FB_AUX_TEXT_S3_MMIO 2 /* S3 MMIO fasttext */
#define FB_AUX_TEXT_MGA_STEP16 3 /* MGA Millenium I: text, attr, 14 reserved bytes */
#define FB_AUX_TEXT_MGA_STEP8 4 /* other MGAs: text, attr, 6 reserved bytes */
#define FB_AUX_TEXT_SVGA_GROUP 8 /* 8-15: SVGA tileblit compatible modes */
#define FB_AUX_TEXT_SVGA_MASK 7 /* lower three bits says step */
#define FB_AUX_TEXT_SVGA_STEP2 8 /* SVGA text mode: text, attr */
#define FB_AUX_TEXT_SVGA_STEP4 9 /* SVGA text mode: text, attr, 2 reserved bytes */
#define FB_AUX_TEXT_SVGA_STEP8 10 /* SVGA text mode: text, attr, 6 reserved bytes */
#define FB_AUX_TEXT_SVGA_STEP16 11 /* SVGA text mode: text, attr, 14 reserved bytes */
#define FB_AUX_TEXT_SVGA_LAST 15 /* reserved up to 15 */

#define FB_AUX_VGA_PLANES_VGA4 0 /* 16 color planes (EGA/VGA) */
#define FB_AUX_VGA_PLANES_CFB4 1 /* CFB4 in planes (VGA) */
#define FB_AUX_VGA_PLANES_CFB8 2 /* CFB8 in planes (VGA) */

#define FB_VISUAL_MONO01 0 /* Monochr. 1=Black 0=White 　1=黑色，２＝白色*/
#define FB_VISUAL_MONO10 1 /* Monochr. 1=White 0=Black 1=白色，２＝黑色*/
#define FB_VISUAL_TRUECOLOR 2 /* True color 真实的颜色 */
#define FB_VISUAL_PSEUDOCOLOR 3 /* Pseudo color (like atari) 伪颜色*/
#define FB_VISUAL_DIRECTCOLOR 4 /* Direct color 直接颜色 */
#define FB_VISUAL_STATIC_PSEUDOCOLOR 5 /* Pseudo color readonly 只读伪颜色*/

#define FB_ACCEL_NONE 0 /* no hardware accelerator 没有硬件加速　*/
#define FB_ACCEL_ATARIBLITT 1 /* Atari Blitter */
#define FB_ACCEL_AMIGABLITT 2 /* Amiga Blitter */
#define FB_ACCEL_S3_TRIO64 3 /* Cybervision64 (S3 Trio64) */
#define FB_ACCEL_NCR_77C32BLT 4 /* RetinaZ3 (NCR 77C32BLT) */
#define FB_ACCEL_S3_VIRGE 5 /* Cybervision64/3D (S3 ViRGE) */
#define FB_ACCEL_ATI_MACH64GX 6 /* ATI Mach 64GX family */
#define FB_ACCEL_DEC_TGA 7 /* DEC 21030 TGA */
#define FB_ACCEL_ATI_MACH64CT 8 /* ATI Mach 64CT family */
#define FB_ACCEL_ATI_MACH64VT 9 /* ATI Mach 64CT family VT class */
#define FB_ACCEL_ATI_MACH64GT 10 /* ATI Mach 64CT family GT class */
#define FB_ACCEL_SUN_CREATOR 11 /* Sun Creator/Creator3D */
#define FB_ACCEL_SUN_CGSIX 12 /* Sun cg6 */
#define FB_ACCEL_SUN_LEO 13 /* Sun leo/zx */
#define FB_ACCEL_IMS_TWINTURBO 14 /* IMS Twin Turbo */
#define FB_ACCEL_3DLABS_PERMEDIA2 15 /* 3Dlabs Permedia 2 */
#define FB_ACCEL_MATROX_MGA2064W 16 /* Matrox MGA2064W (Millenium) */
#define FB_ACCEL_MATROX_MGA1064SG 17 /* Matrox MGA1064SG (Mystique) */
#define FB_ACCEL_MATROX_MGA2164W 18 /* Matrox MGA2164W (Millenium II) */
#define FB_ACCEL_MATROX_MGA2164W_AGP 19 /* Matrox MGA2164W (Millenium II) */
#define FB_ACCEL_MATROX_MGAG100 20 /* Matrox G100 (Productiva G100) */
#define FB_ACCEL_MATROX_MGAG200 21 /* Matrox G200 (Myst, Mill, ...) */
#define FB_ACCEL_SUN_CG14 22 /* Sun cgfourteen */
#define FB_ACCEL_SUN_BWTWO 23 /* Sun bwtwo */
#define FB_ACCEL_SUN_CGTHREE 24 /* Sun cgthree */
#define FB_ACCEL_SUN_TCX 25 /* Sun tcx */
#define FB_ACCEL_MATROX_MGAG400 26 /* Matrox G400 */
#define FB_ACCEL_NV3 27 /* nVidia RIVA 128 */
#define FB_ACCEL_NV4 28 /* nVidia RIVA TNT */
#define FB_ACCEL_NV5 29 /* nVidia RIVA TNT2 */
#define FB_ACCEL_CT_6555x 30 /* C&T 6555x */
#define FB_ACCEL_3DFX_BANSHEE 31 /* 3Dfx Banshee */
#define FB_ACCEL_ATI_RAGE128 32 /* ATI Rage128 family */
#define FB_ACCEL_IGS_CYBER2000 33 /* CyberPro 2000 */
#define FB_ACCEL_IGS_CYBER2010 34 /* CyberPro 2010 */
#define FB_ACCEL_IGS_CYBER5000 35 /* CyberPro 5000 */
#define FB_ACCEL_SIS_GLAMOUR 36 /* SiS 300/630/540 */
#define FB_ACCEL_3DLABS_PERMEDIA3 37 /* 3Dlabs Permedia 3 */
#define FB_ACCEL_ATI_RADEON 38 /* ATI Radeon family */
#define FB_ACCEL_I810 39 /* Intel 810/815 */
#define FB_ACCEL_SIS_GLAMOUR_2 40 /* SiS 315, 650, 740 */
#define FB_ACCEL_SIS_XABRE 41 /* SiS 330 ("Xabre") */
#define FB_ACCEL_I830 42 /* Intel 830M/845G/85x/865G */
#define FB_ACCEL_NV_10 43 /* nVidia Arch 10 */
#define FB_ACCEL_NV_20 44 /* nVidia Arch 20 */
#define FB_ACCEL_NV_30 45 /* nVidia Arch 30 */
#define FB_ACCEL_NV_40 46 /* nVidia Arch 40 */
#define FB_ACCEL_XGI_VOLARI_V 47 /* XGI Volari V3XT, V5, V8 */
#define FB_ACCEL_XGI_VOLARI_Z 48 /* XGI Volari Z7 */
#define FB_ACCEL_OMAP1610 49 /* TI OMAP16xx */
#define FB_ACCEL_TRIDENT_TGUI 50 /* Trident TGUI */
#define FB_ACCEL_TRIDENT_3DIMAGE 51 /* Trident 3DImage */
#define FB_ACCEL_TRIDENT_BLADE3D 52 /* Trident Blade3D */
#define FB_ACCEL_TRIDENT_BLADEXP 53 /* Trident BladeXP */
#define FB_ACCEL_CIRRUS_ALPINE 53 /* Cirrus Logic 543x/544x/5480 */
#define FB_ACCEL_NEOMAGIC_NM2070 90 /* NeoMagic NM2070 */
#define FB_ACCEL_NEOMAGIC_NM2090 91 /* NeoMagic NM2090 */
#define FB_ACCEL_NEOMAGIC_NM2093 92 /* NeoMagic NM2093 */
#define FB_ACCEL_NEOMAGIC_NM2097 93 /* NeoMagic NM2097 */
#define FB_ACCEL_NEOMAGIC_NM2160 94 /* NeoMagic NM2160 */
#define FB_ACCEL_NEOMAGIC_NM2200 95 /* NeoMagic NM2200 */
#define FB_ACCEL_NEOMAGIC_NM2230 96 /* NeoMagic NM2230 */
#define FB_ACCEL_NEOMAGIC_NM2360 97 /* NeoMagic NM2360 */
#define FB_ACCEL_NEOMAGIC_NM2380 98 /* NeoMagic NM2380 */
#define FB_ACCEL_PXA3XX 99 /* PXA3xx */

#define FB_ACCEL_SAVAGE4 0x80 /* S3 Savage4 */
#define FB_ACCEL_SAVAGE3D 0x81 /* S3 Savage3D */
#define FB_ACCEL_SAVAGE3D_MV 0x82 /* S3 Savage3D-MV */
#define FB_ACCEL_SAVAGE2000 0x83 /* S3 Savage2000 */
#define FB_ACCEL_SAVAGE_MX_MV 0x84 /* S3 Savage/MX-MV */
#define FB_ACCEL_SAVAGE_MX 0x85 /* S3 Savage/MX */
#define FB_ACCEL_SAVAGE_IX_MV 0x86 /* S3 Savage/IX-MV */
#define FB_ACCEL_SAVAGE_IX 0x87 /* S3 Savage/IX */
#define FB_ACCEL_PROSAVAGE_PM 0x88 /* S3 ProSavage PM133 */
#define FB_ACCEL_PROSAVAGE_KM 0x89 /* S3 ProSavage KM133 */
#define FB_ACCEL_S3TWISTER_P 0x8a /* S3 Twister */
#define FB_ACCEL_S3TWISTER_K 0x8b /* S3 TwisterK */
#define FB_ACCEL_SUPERSAVAGE 0x8c /* S3 Supersavage */
#define FB_ACCEL_PROSAVAGE_DDR 0x8d /* S3 ProSavage DDR */
#define FB_ACCEL_PROSAVAGE_DDRK 0x8e /* S3 ProSavage DDR-K */


/** * 该结构体用于描述显卡自身的属性 * 包括识别符，缓存地址，显卡类型等 * */
struct fb_fix_screeninfo {
    char id[16];            /* identification string eg "TT Builtin" 标识符字符串*/
    unsigned long smem_start;   /* Start of frame buffer mem 　frame buffer所占内存的开始地址　*/
                    /* (physical address) 这里说的是物理地址　*/
    __u32 smem_len;         /* Length of frame buffer mem frame buffer所占内存的长度 */
    __u32 type;         /* see FB_TYPE_* 查看FB_BYTE_* */
    __u32 type_aux;         /* Interleave for interleaved Planes 交织交错的平面　*/
    __u32 visual;           /* see FB_VISUAL_* 查看FB_VISUAL_* */ 
    __u16 xpanstep;         /* zero if no hardware panning 如何没有硬件支持的话为0 */
    __u16 ypanstep;         /* zero if no hardware panning 如果没有硬件支持的话为０*/
    __u16 ywrapstep;        /* zero if no hardware ywrap　如果没有硬件ywrap的话为０　*/
    __u32 line_length;      /* length of a line in bytes 一行的长度，以byte为单位 */
    unsigned long mmio_start;   /* Start of Memory Mapped I/O 映射到I/O的内存的开始地址 */
                    /* (physical address) 物理地址*/
    __u32 mmio_len;         /* Length of Memory Mapped I/O 映射到I/O的内存长度*/
    __u32 accel;            /* Indicate to driver which 指示到驱动程序　*/
                    /* specific chip/card we have 特别是我们拥有的芯片/卡*/
    __u16 reserved[3];      /* Reserved for future compatibility 为后来的兼容性保留*/
};

/* Interpretation of offset for color fields: All offsets are from the right, * inside a "pixel" value, which is exactly 'bits_per_pixel' wide (means: you * can use the offset as right argument to <<). A pixel afterwards is a bit * stream and is written to video memory as that unmodified. * * 色域偏移的解释：所有的偏移量都来自于右边，在一个＂像素＂值里面，实际上是'bits_per_pixel' * 的宽度（也就是说：你可以使用该偏移量作为 << 的右参数）．一个像素之后是一个位流，并且 *　作为未被修改而被写到视频内存中． * * For pseudocolor: offset and length should be the same for all color * components. Offset specifies the position of the least significant bit * of the pallette index in a pixel value. Length indicates the number * of available palette entries (i.e. # of entries = 1 << length). * * 对于伪色彩来说：对于所有的颜色部分，偏移量和长度应该是相同的．偏移量指定了 *　在一个像素值里的调色板索引的最低有效位的位置．长度指明了可用的调色板入口的 * 数量． */　
struct fb_bitfield {
    __u32 offset;           /* 位域的开始 */
    __u32 length;           /* length of bitfield　位域的长度　*/
    __u32 msb_right;        /* != 0 : Most significant bit is　不等于０，大多数重要的位是右边的 */ 
                    /* right */ 
};

#define FB_NONSTD_HAM 1 /* Hold-And-Modify (HAM) 保持和修改 */
#define FB_NONSTD_REV_PIX_IN_B 2 /* order of pixels in each byte is reversed 在每一个字节中的像素的顺序被保留下来　*/

#define FB_ACTIVATE_NOW 0 /* set values immediately (or vbl) 立即设定颜色　*/
#define FB_ACTIVATE_NXTOPEN 1 /* activate on next open 在下一个打开的时候激活　*/
#define FB_ACTIVATE_TEST 2 /* don't set, round up impossible 不设置 */
#define FB_ACTIVATE_MASK 15
                    /* values */
#define FB_ACTIVATE_VBL 16 /* activate values on next vbl 在下一个vbl的时候激活值 */
#define FB_CHANGE_CMAP_VBL 32 /* change colormap on vbl 在vbl的时候改变色彩映射　*/
#define FB_ACTIVATE_ALL 64 /* change all VCs on this fb 在这个fb中改变所有的VC */
#define FB_ACTIVATE_FORCE 128 /* force apply even when no change */
#define FB_ACTIVATE_INV_MODE 256 /* invalidate videomode 即使在没有改变无效视频模式的时候强制应用　*/

#define FB_ACCELF_TEXT 1 /* (OBSOLETE) see fb_info.flags and vc_mode 已过时 */

#define FB_SYNC_HOR_HIGH_ACT 1 /* horizontal sync high active 高活性水平同步　*/
#define FB_SYNC_VERT_HIGH_ACT 2 /* vertical sync high active 高活性垂直同步　*/
#define FB_SYNC_EXT 4 /* external sync 外部同步　*/
#define FB_SYNC_COMP_HIGH_ACT 8 /* composite sync high active 高活性复合同步　 */
#define FB_SYNC_BROADCAST 16 /* broadcast video timings 广播视频时序 */
                    /* vtotal = 144d/288n/576i => PAL */
                    /* vtotal = 121d/242n/484i => NTSC */
#define FB_SYNC_ON_GREEN 32 /* sync on green 在绿色下同步　*/

#define FB_VMODE_NONINTERLACED 0 /* non interlaced 非交错模式　*/
#define FB_VMODE_INTERLACED 1 /* interlaced 交错模式　*/
#define FB_VMODE_DOUBLE 2 /* double scan 双扫描模式 */
#define FB_VMODE_ODD_FLD_FIRST 4 /* interlaced: top line first 交错的：顶行优先　*/
#define FB_VMODE_MASK 255

#define FB_VMODE_YWRAP 256 /* ywrap instead of panning ywrap而不是panning */
#define FB_VMODE_SMOOTH_XPAN 512 /* smooth xpan possible (internally used) 平滑的xpan(内部使用) */
#define FB_VMODE_CONUPDATE 512 /* don't update x/yoffset 不要更新 x/yoffset*/

/* * Display rotation support * * 旋转支持显示 */
#define FB_ROTATE_UR 0
#define FB_ROTATE_CW 1
#define FB_ROTATE_UD 2
#define FB_ROTATE_CCW 3

#define PICOS2KHZ(a) (1000000000UL/(a))
#define KHZ2PICOS(a) (1000000000UL/(a))

/** * 用于描述显卡的一般特性，比如实际分辨率，虚拟分辨率，实际分辨率和虚拟 *　分辨率之间的位移等 　*/
struct fb_var_screeninfo {
    __u32 xres;         /* visible resolution 可见解析度 */
    __u32 yres;
    __u32 xres_virtual;     /* virtual resolution 虚拟解析度 */
    __u32 yres_virtual;
    __u32 xoffset;          /* offset from virtual to visible 虚拟到可见的偏移量 */
    __u32 yoffset;          /* resolution */

    __u32 bits_per_pixel;       /* guess what BPP : 每个像素的位数 */
    __u32 grayscale;        /* != 0 Graylevels instead of colors !=０指灰度而不是颜色 */

    //如果是真实的颜色的话表示在fb内存中的位域，如果不是颜色的话，仅仅就是长度
    //在这里保存的是fb缓存的R/G/B位域
    struct fb_bitfield red;     /* bitfield in fb mem if true color, */
    struct fb_bitfield green;   /* else only length is significant */
    struct fb_bitfield blue;
    struct fb_bitfield transp;  /* transparency 透明度 */  

    __u32 nonstd;           /* != 0 Non standard pixel format !=0 非标准像素格式 */

    __u32 activate;         /* see FB_ACTIVATE_* 查看FB_ACTIVATE_* */

    __u32 height;           /* height of picture in mm 在内存中图片的高度　*/
    __u32 width;            /* width of picture in mm 在内存中图片的宽度 */

    __u32 accel_flags;      /* (OBSOLETE) see fb_info.flags 已过时*/

    /* Timing: All values in pixclocks, except pixclock (of course) */
    /* 除了pixclock本身外，其他的都已pixclock为单位*/
    __u32 pixclock;         /* pixel clock in ps (pico seconds) 像素时钟（皮秒）*/
    __u32 left_margin;      /* time from sync to picture 行切换：从绘图到同步之间的延迟　*/
    __u32 right_margin;     /* time from picture to sync 行切换：从绘图到同步之间的延迟　*/
    __u32 upper_margin;     /* time from sync to picture 帧切换：从同步到绘图之间的延迟　*/
    __u32 lower_margin;　　　　　//　帧切换，从绘图到同步之间的延迟　
    __u32 hsync_len;        /* length of horizontal sync 水平同步的长度　*/
    __u32 vsync_len;        /* length of vertical sync 垂直同步的长度　*/
    __u32 sync;         /* see FB_SYNC_* 查看FB_SYNC_*　*/
    __u32 vmode;            /* see FB_VMODE_* 查看 FB_VMODE_* */
    __u32 rotate;           /* angle we rotate counter clockwise 顺时针旋转的角度 */
    __u32 reserved[5];      /* Reserved for future compatibility 保留 */
};

/** * 用于描述设备无关的颜色映射信息 */
struct fb_cmap {
    __u32 start;            /* First entry 第一个元素入口 */
    __u32 len;          /* Number of entries 元素的数量*/
    //R,G,B,透明度
    __u16 *red;         /* Red values */
    __u16 *green;
    __u16 *blue;
    __u16 *transp;          /* transparency, can be NULL 透明度，可以为空 */
};

struct fb_con2fbmap {
    __u32 console;
    __u32 framebuffer;
};

/* VESA Blanking Levels */
#define VESA_NO_BLANKING 0
#define VESA_VSYNC_SUSPEND 1
#define VESA_HSYNC_SUSPEND 2
#define VESA_POWERDOWN 3


enum {
    /* screen: unblanked, hsync: on, vsync: on */
    FB_BLANK_UNBLANK       = VESA_NO_BLANKING,

    /* screen: blanked, hsync: on, vsync: on */
    FB_BLANK_NORMAL        = VESA_NO_BLANKING + 1,

    /* screen: blanked, hsync: on, vsync: off */
    FB_BLANK_VSYNC_SUSPEND = VESA_VSYNC_SUSPEND + 1,

    /* screen: blanked, hsync: off, vsync: on */
    FB_BLANK_HSYNC_SUSPEND = VESA_HSYNC_SUSPEND + 1,

    /* screen: blanked, hsync: off, vsync: off */
    FB_BLANK_POWERDOWN     = VESA_POWERDOWN + 1
};

#define FB_VBLANK_VBLANKING 0x001 /* currently in a vertical blank */
#define FB_VBLANK_HBLANKING 0x002 /* currently in a horizontal blank */
#define FB_VBLANK_HAVE_VBLANK 0x004 /* vertical blanks can be detected */
#define FB_VBLANK_HAVE_HBLANK 0x008 /* horizontal blanks can be detected */
#define FB_VBLANK_HAVE_COUNT 0x010 /* global retrace counter is available */
#define FB_VBLANK_HAVE_VCOUNT 0x020 /* the vcount field is valid */
#define FB_VBLANK_HAVE_HCOUNT 0x040 /* the hcount field is valid */
#define FB_VBLANK_VSYNCING 0x080 /* currently in a vsync */
#define FB_VBLANK_HAVE_VSYNC 0x100 /* verical syncs can be detected */

struct fb_vblank {
    __u32 flags;            /* FB_VBLANK flags FB_VBLANK标志 */
    __u32 count;            /* counter of retraces since boot 启动之后追溯的次数　*/
    __u32 vcount;           /* current scanline position 当前扫描行位置　*/
    __u32 hcount;           /* current scandot position 当前扫描点位置　*/
    __u32 reserved[4];      /* reserved for future compatibility 保留　*/
};

/* Internal HW accel 内部硬件加速　*/
#define ROP_COPY 0
#define ROP_XOR 1

//复制区域　
struct fb_copyarea {
    __u32 dx;
    __u32 dy;
    __u32 width;
    __u32 height;
    __u32 sx;
    __u32 sy;
};

//回执矩形
struct fb_fillrect {
    __u32 dx;   /* screen-relative 屏幕相关 */
    __u32 dy;
    __u32 width;
    __u32 height;
    __u32 color;
    __u32 rop;
};

struct fb_image {
    __u32 dx;       /* Where to place image 图像放在哪里　*/
    __u32 dy;
    __u32 width;        /* Size of image 图像的宽度和高度　*/
    __u32 height;
    __u32 fg_color;     /* Only used when a mono bitmap 仅仅是单色图像的时候使用　*/
    __u32 bg_color;
    __u8  depth;        /* Depth of the image 图像的深度　*/
    const char *data;   /* Pointer to image data 指向图像数据的指针　*/
    struct fb_cmap cmap;    /* color map info 颜色映射信息　*/
};

/* * hardware cursor control * 硬件光标控制　 */

#define FB_CUR_SETIMAGE 0x01
#define FB_CUR_SETPOS 0x02
#define FB_CUR_SETHOT 0x04
#define FB_CUR_SETCMAP 0x08
#define FB_CUR_SETSHAPE 0x10
#define FB_CUR_SETSIZE 0x20
#define FB_CUR_SETALL 0xFF

//　光标位置　
struct fbcurpos {
    __u16 x, y;
};

struct fb_cursor {
    __u16 set;      /* what to set 设置成什么　*/
    __u16 enable;       /* cursor on/off 光标打开/关闭　*/
    __u16 rop;      /* bitop operation 位操作　*/
    const char *mask;   /* cursor mask bits 光标掩码位 */
    struct fbcurpos hot;    /* cursor hot spot 光标热点　*/
    struct fb_image image;  /* Cursor image 光标图像　*/
};

#ifdef CONFIG_FB_BACKLIGHT
/* Settings for the generic backlight code */
#define FB_BACKLIGHT_LEVELS 128
#define FB_BACKLIGHT_MAX 0xFF
#endif

#ifdef __KERNEL__

#include <linux/fs.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/workqueue.h>
#include <linux/notifier.h>
#include <linux/list.h>
#include <linux/backlight.h>
#include <asm/io.h>

struct vm_area_struct;
struct fb_info;
struct device;
struct file;

/* Definitions below are used in the parsed monitor specs */
#define FB_DPMS_ACTIVE_OFF 1
#define FB_DPMS_SUSPEND 2
#define FB_DPMS_STANDBY 4

#define FB_DISP_DDI 1
#define FB_DISP_ANA_700_300 2
#define FB_DISP_ANA_714_286 4
#define FB_DISP_ANA_1000_400 8
#define FB_DISP_ANA_700_000 16

#define FB_DISP_MONO 32
#define FB_DISP_RGB 64
#define FB_DISP_MULTI 128
#define FB_DISP_UNKNOWN 256

#define FB_SIGNAL_NONE 0
#define FB_SIGNAL_BLANK_BLANK 1
#define FB_SIGNAL_SEPARATE 2
#define FB_SIGNAL_COMPOSITE 4
#define FB_SIGNAL_SYNC_ON_GREEN 8
#define FB_SIGNAL_SERRATION_ON 16

#define FB_MISC_PRIM_COLOR 1
#define FB_MISC_1ST_DETAIL 2 /* First Detailed Timing is preferred 第一次详细的时间是首选　*/

struct fb_chroma {
    __u32 redx; /* in fraction of 1024 1024的一小部分　*/
    __u32 greenx;
    __u32 bluex;
    __u32 whitex;
    __u32 redy;
    __u32 greeny;
    __u32 bluey;
    __u32 whitey;
};

struct fb_monspecs {
    struct fb_chroma chroma;
    struct fb_videomode *modedb;    /* mode database 模式数据库 */
    __u8  manufacturer[4];      /* Manufacturer 制造商　*/
    __u8  monitor[14];      /* Monitor String 监视字符串　*/
    __u8  serial_no[14];        /* Serial Number 序列号　*/
    __u8  ascii[14];        /* ? */
    __u32 modedb_len;       /* mode database length 模式数据库长度　*/
    __u32 model;            /* Monitor Model 监视模型　*/
    __u32 serial;           /* Serial Number - Integer 序列号－整数　*/
    __u32 year;         /* Year manufactured 制造年*/
    __u32 week;         /* Week Manufactured 制造周　*/
    __u32 hfmin;            /* hfreq lower limit (Hz) hfreq最低限制*/
    __u32 hfmax;            /* hfreq upper limit (Hz) hfreq最高限制*/
    __u32 dclkmin;          /* pixelclock lower limit (Hz) pixelclock最低限制*/
    __u32 dclkmax;          /* pixelclock upper limit (Hz) pixelclock最高限制*/
    __u16 input;            /* display type - see FB_DISP_* 显示类型　- 查看FB_DISP_*　*/
    __u16 dpms;         /* DPMS support - see FB_DPMS_ DPMS支持－查看FB_DPMS_ */
    __u16 signal;           /* Signal Type - see FB_SIGNAL_* 信号类型　－　查看FB_SIGNAL_*　*/
    __u16 vfmin;            /* vfreq lower limit (Hz) vfreq最低限制　*/
    __u16 vfmax;            /* vfreq upper limit (Hz) vfreq最高限制　*/
    __u16 gamma;            /* Gamma - in fractions of 100 100的分数　*/
    __u16 gtf   : 1;        /* supports GTF 支持 GTF */
    __u16 misc;         /* Misc flags - see FB_MISC_* Misc标识　－　查看FB_MISC_*　　*/
    __u8  version;          /* EDID version... EDID版本　*/
    __u8  revision;         /* ...and revision 修订版本　*/
    __u8  max_x;            /* Maximum horizontal size (cm) 最大水平大小　*/
    __u8  max_y;            /* Maximum vertical size (cm) 最大垂直大小　*/
};

struct fb_cmap_user {
    __u32 start;            /* First entry 第一元素入口　　*/
    __u32 len;          /* Number of entries 元素的数量　*/
    //R,G,B和透明度　
    __u16 __user *red;      /* Red values */
    __u16 __user *green;
    __u16 __user *blue;
    __u16 __user *transp;       /* transparency, can be NULL */
};

struct fb_image_user {
    __u32 dx;           /* Where to place image */
    __u32 dy;
    __u32 width;            /* Size of image */
    __u32 height;
    __u32 fg_color;         /* Only used when a mono bitmap */
    __u32 bg_color;
    __u8  depth;            /* Depth of the image */
    const char __user *data;    /* Pointer to image data */
    struct fb_cmap_user cmap;   /* color map info */
};

struct fb_cursor_user {
    __u16 set;          /* what to set */
    __u16 enable;           /* cursor on/off */
    __u16 rop;          /* bitop operation */
    const char __user *mask;    /* cursor mask bits */
    struct fbcurpos hot;        /* cursor hot spot */
    struct fb_image_user image; /* Cursor image */
};

/* * Register/unregister for framebuffer events 　* framebuffer事件的注册/注销 */

/* The resolution of the passed in fb_info about to change */
//　在fb_info中通过的分辨率将要改变
#define FB_EVENT_MODE_CHANGE 0x01
/* The display on this fb_info is beeing suspended, no access to the * framebuffer is allowed any more after that call returns * 在这个fb_info的显示是被悬挂着的，在那个调用返回之后的对framebuffer * 的访问是不被允许的． */
#define FB_EVENT_SUSPEND 0x02
/* The display on this fb_info was resumed, you can restore the display * if you own it 　* 在这个fb_info中的显示恢复了，如果你拥有他，你可以恢复显示 * */
#define FB_EVENT_RESUME 0x03
/* An entry from the modelist was removed */
//　模式列表中的一个元素被移走了
#define FB_EVENT_MODE_DELETE 0x04
/* A driver registered itself */
// 一个驱动注册了他自己
#define FB_EVENT_FB_REGISTERED 0x05
/* A driver unregistered itself */
// 一个驱动注销了他自己　
#define FB_EVENT_FB_UNREGISTERED 0x06
/* CONSOLE-SPECIFIC: get console to framebuffer mapping */
// 获取framebuffer映射的控制台
#define FB_EVENT_GET_CONSOLE_MAP 0x07
/* CONSOLE-SPECIFIC: set console to framebuffer mapping */
//　设置framebuffer映射的控制台
#define FB_EVENT_SET_CONSOLE_MAP 0x08
/* A hardware display blank change occured */
// 一个硬件显示空改变发生了
#define FB_EVENT_BLANK 0x09
/* Private modelist is to be replaced */
// 内部的模式列表将被替换
#define FB_EVENT_NEW_MODELIST 0x0A
/* The resolution of the passed in fb_info about to change and all vc's should be changed */
// 在fb_info中通过的分辨率将要改变，并且所有的vc应该被改变
#define FB_EVENT_MODE_CHANGE_ALL 0x0B
/* A software display blank change occured */
// 一个软件显示空改变发生了
#define FB_EVENT_CONBLANK 0x0C
/* Get drawing requirements */
// 获取画图需求
#define FB_EVENT_GET_REQ 0x0D
/* Unbind from the console if possible */
// 如果可能的话从控制台中接触绑定
#define FB_EVENT_FB_UNBIND 0x0E
/* CONSOLE-SPECIFIC: remap all consoles to new fb - for vga switcheroo */
// 重新将所有的控制台映射到新的fb -- 对于vga switcheroo来说的
#define FB_EVENT_REMAP_ALL_CONSOLE 0x0F

struct fb_event {
    struct fb_info *info;
    void *data;
};

struct fb_blit_caps {
    u32 x;
    u32 y;
    u32 len;
    u32 flags;
};

extern int fb_register_client(struct notifier_block *nb);
extern int fb_unregister_client(struct notifier_block *nb);
extern int fb_notifier_call_chain(unsigned long val, void *v);
/* * Pixmap structure definition *　Pixmap 结构体定义　 * The purpose of this structure is to translate data * from the hardware independent format of fbdev to what * format the hardware needs. * 该结构体的目的就是将数据从fbdev的硬件独立的格式转换成 *　硬件需要的格式 * */

#define FB_PIXMAP_DEFAULT 1 /* used internally by fbcon 被fvbcon内部使用*/
#define FB_PIXMAP_SYSTEM 2 /* memory is in system RAM 内存在系统RAM中*/
#define FB_PIXMAP_IO 4 /* memory is iomapped 内存被io映射了*/
#define FB_PIXMAP_SYNC 256 /* set if GPU can DMA 如果GPU能够使用DMA的话设置*/

struct fb_pixmap {
    u8  *addr;      /* pointer to memory 指向内存的指针 */
    u32 size;       /* size of buffer in bytes 缓冲的字节数大小 */
    u32 offset;     /* current offset to buffer 　当前到buffer的偏移量　　 */
    u32 buf_align;      /* byte alignment of each bitmap　　每一个位图的字节对齐 */
    u32 scan_align;     /* alignment per scanline 每一个扫描行的对齐 */
    u32 access_align;   /* alignment per read/write (bits)　每一个读写位的对齐 */
    u32 flags;      /* see FB_PIXMAP_* 查看FB_PIXMAP_* */
    u32 blit_x;             /* supported bit block dimensions (1-32) 支持位块尺寸(1-32) */
    u32 blit_y;             /* Format: blit_x = 1 << (width - 1) */
                            /* blit_y = 1 << (height - 1) */
                            /* if 0, will be set to 0xffffffff (all)　如果是０，则被设置为0xffffffff */
    /* access methods 访问方法　*/
    void (*writeio)(struct fb_info *info, void __iomem *dst, void *src, unsigned int size);
    void (*readio) (struct fb_info *info, void *dst, void __iomem *src, unsigned int size);
};

#ifdef CONFIG_FB_DEFERRED_IO
struct fb_deferred_io {
    /* delay between mkwrite and deferred handler 　在mkwrite和延期的处理程序的时间　*/
    unsigned long delay;
    struct mutex lock; /* mutex that protects the page list 保护页列表的互斥锁　*/
    struct list_head pagelist; /* list of touched pages 被创建的页的列表*/
    /* callback 回调函数*/
    void (*deferred_io)(struct fb_info *info, struct list_head *pagelist);
};
#endif

/* * Frame buffer operations *　Frame buffer 的操作 * LOCKING NOTE: those functions must _ALL_ be called with the console * semaphore held, this is the only suitable locking mechanism we have * in 2.6. Some may be called at interrupt time at this point though. 　* 这些函数必须要使用semaphore锁． */

struct fb_ops {
    /* open/release and usage marking */
    //　打开/释放和使用标记
    struct module *owner;
    int (*fb_open)(struct fb_info *info, int user);
    int (*fb_release)(struct fb_info *info, int user);

    /* For framebuffers with strange non linear layouts or that do not * work with normal memory mapped access * 对于拥有陌生的非线性布局的framebuffer来说，不能使用普通的内存 *　映射访问来工作 */
    ssize_t (*fb_read)(struct fb_info *info, char __user *buf,
               size_t count, loff_t *ppos);
    ssize_t (*fb_write)(struct fb_info *info, const char __user *buf,
                size_t count, loff_t *ppos);

    /* checks var and eventually tweaks it to something supported, * DO NOT MODIFY PAR */
    // 检查var并且事件性的调整到可支持状态．不要修改PAR
    int (*fb_check_var)(struct fb_var_screeninfo *var, struct fb_info *info);

    /* set the video mode according to info->var */
    // 通过info->var设置视频模式
    int (*fb_set_par)(struct fb_info *info);

    /* set color register */
    // 设置颜色寄存器
    int (*fb_setcolreg)(unsigned regno, unsigned red, unsigned green,
                unsigned blue, unsigned transp, struct fb_info *info);

    /* set color registers in batch */
    // 批处理设置颜色寄存器
    int (*fb_setcmap)(struct fb_cmap *cmap, struct fb_info *info);

    /* blank display */
    // 空显示
    int (*fb_blank)(int blank, struct fb_info *info);

    /* pan display */
    // pan 显示
    int (*fb_pan_display)(struct fb_var_screeninfo *var, struct fb_info *info);

    /* Draws a rectangle */
    // 绘制一个矩形
    void (*fb_fillrect) (struct fb_info *info, const struct fb_fillrect *rect);
    /* Copy data from area to another */
    //　从一个区域复制数据到另外一个区域
    void (*fb_copyarea) (struct fb_info *info, const struct fb_copyarea *region);
    /* Draws a image to the display */
    // 在显示器上绘制一个图像
    void (*fb_imageblit) (struct fb_info *info, const struct fb_image *image);

    /* Draws cursor */
    // 绘制光标
    int (*fb_cursor) (struct fb_info *info, struct fb_cursor *cursor);

    /* Rotates the display */
    // 旋转显示
    void (*fb_rotate)(struct fb_info *info, int angle);

    /* wait for blit idle, optional */
    // 等待blit空闲，可选
    int (*fb_sync)(struct fb_info *info);

    /* perform fb specific ioctl (optional) */
    // 运行fb指定的ioctl(可选)
    int (*fb_ioctl)(struct fb_info *info, unsigned int cmd,
            unsigned long arg);

    /* Handle 32bit compat ioctl (optional) */
    //　处理３２位兼容的ioctl
    int (*fb_compat_ioctl)(struct fb_info *info, unsigned cmd,
            unsigned long arg);

    /* perform fb specific mmap */
    // 运行fb指定的mmap
    int (*fb_mmap)(struct fb_info *info, struct vm_area_struct *vma);

    /* get capability given var */
    // 获取给定的var的能力
    void (*fb_get_caps)(struct fb_info *info, struct fb_blit_caps *caps,
                struct fb_var_screeninfo *var);

    /* teardown any resources to do with this framebuffer */
    // 卸载与该framebuffer相关的任何资源
    void (*fb_destroy)(struct fb_info *info);
};

#ifdef CONFIG_FB_TILEBLITTING
#define FB_TILE_CURSOR_NONE 0
#define FB_TILE_CURSOR_UNDERLINE 1
#define FB_TILE_CURSOR_LOWER_THIRD 2
#define FB_TILE_CURSOR_LOWER_HALF 3
#define FB_TILE_CURSOR_TWO_THIRDS 4
#define FB_TILE_CURSOR_BLOCK 5

struct fb_tilemap {
    __u32 width;                /* width of each tile in pixels　像素的宽度 */
    __u32 height;               /* height of each tile in scanlines 扫描行的高度　*/
    __u32 depth;                /* color depth of each tile 颜色深度　*/
    __u32 length;               /* number of tiles in the map 在映射中的数量　*/
    const __u8 *data;           /* actual tile map: a bitmap array, packed to the nearest byte 实际映射：一个位图数组，被打包到最近的位　*/
};

struct fb_tilerect {
    __u32 sx;                   /* origin in the x-axis 在x轴中原点*/
    __u32 sy;                   /* origin in the y-axis 在y轴中的原点*/
    __u32 width;                /* number of tiles in the x-axis 在x-axis 中的数量　*/
    __u32 height;               /* number of tiles in the y-axis 在y-axis中的数量　*/
    __u32 index;                /* what tile to use: index to tile map 使用哪一个tile:到tile映射的索引　*/
    __u32 fg;                   /* foreground color 前景色 */
    __u32 bg;                   /* background color 后景色 */
    __u32 rop;                  /* raster operation 光栅操作　*/
};

struct fb_tilearea {
    __u32 sx;                   /* source origin in the x-axis 在X轴的源原点　*/
    __u32 sy;                   /* source origin in the y-axis 在y轴的源原点　*/
    __u32 dx;                   /* destination origin in the x-axis 在x轴的目的原点　*/
    __u32 dy;                   /* destination origin in the y-axis 在y轴的目的原点　*/
    __u32 width;                /* number of tiles in the x-axis 在x轴中的tiles的数量　*/
    __u32 height;               /* number of tiles in the y-axis 在y轴中的tiles的数量　*/
};

struct fb_tileblit {
    __u32 sx;                   /* origin in the x-axis　在x轴的原点 */
    __u32 sy;                   /* origin in the y-axis 在y轴的原点*/
    __u32 width;                /* number of tiles in the x-axis 在x轴上的tiles的数量 */
    __u32 height;               /* number of tiles in the y-axis 在y轴上的tiles的数量　*/
    __u32 fg;                   /* foreground color 前景色*/
    __u32 bg;                   /* background color 后景色*/
    __u32 length;               /* number of tiles to draw 要绘制的tiles的数量 */
    __u32 *indices;             /* array of indices to tile map 到tile映射的指数数组 */
};

struct fb_tilecursor {
    __u32 sx;                   /* cursor position in the x-axis 在x轴的光标位置*/
    __u32 sy;                   /* cursor position in the y-axis 在y轴的光标位置　*/
    __u32 mode;                 /* 0 = erase, 1 = draw 0 = 擦除，１＝绘制*/
    __u32 shape;                /* see FB_TILE_CURSOR_* 查看FB_TILE_CURSOR_* */
    __u32 fg;                   /* foreground color 前景色*/
    __u32 bg;                   /* background color 后景色*/
};

struct fb_tile_ops {
    /* set tile characteristics 　设置tile的特征*/
    void (*fb_settile)(struct fb_info *info, struct fb_tilemap *map);

    /* all dimensions from hereon are in terms of tiles */
    //　从现在起，所有尺寸都在tiles方面
    /* move a rectangular region of tiles from one area to another*/
    // 移动一个矩形区域从一个地方到另外一个地方
    void (*fb_tilecopy)(struct fb_info *info, struct fb_tilearea *area);
    /* fill a rectangular region with a tile */
    // 使用一个tile填充一个矩形区域
    void (*fb_tilefill)(struct fb_info *info, struct fb_tilerect *rect);
    /* copy an array of tiles */    
    // 复制一个tile数组
    void (*fb_tileblit)(struct fb_info *info, struct fb_tileblit *blit);
    /* cursor */
    // 光标
    void (*fb_tilecursor)(struct fb_info *info,
                  struct fb_tilecursor *cursor);
    /* get maximum length of the tile map */
    // 获取tile映射的最大长度
    int (*fb_get_tilemax)(struct fb_info *info);
};
#endif /* CONFIG_FB_TILEBLITTING */

/* FBINFO_* = fb_info.flags bit flags FBINFO_*　＝　fb_info.flags　位标识　*/
#define FBINFO_MODULE 0x0001 /* Low-level driver is a module　底层驱动是一个模块 */
#define FBINFO_HWACCEL_DISABLED 0x0002
    /* When FBINFO_HWACCEL_DISABLED is set: * Hardware acceleration is turned off. Software implementations * of required functions (copyarea(), fillrect(), and imageblit()) * takes over; acceleration engine should be in a quiescent state */
    /* 当FBINFO_HWACCEL_DISABLED被设置的时候： * 硬件加速被关掉．所需功能的软件实现(copyarea(),fillrect()和imageblit()) * 接管．加速引擎应该位域静态状态 * /* hints 提示*/
#define FBINFO_VIRTFB 0x0004 /* FB is System RAM, not device. FB是系统RAM，不是设备*/
#define FBINFO_PARTIAL_PAN_OK 0x0040 /* otw use pan only for double-buffering otw使用pan仅仅用于双缓冲 */
#define FBINFO_READS_FAST 0x0080 /* soft-copy faster than rendering 软拷贝快于渲染 */

/* hardware supported ops */
/* semantics: when a bit is set, it indicates that the operation is * accelerated by hardware. 　* 支持的硬件操作 　* 语义：当一个位被设置，意味着操作被硬件加速了 * * required functions will still work even if the bit is not set. 　* 即使位没有被设置，所需的功能依旧工作． * optional functions may not even exist if the flag bit is not set. * 如果标识位没有被设置，可选的功能可能甚至不存在 */
#define FBINFO_HWACCEL_NONE 0x0000
#define FBINFO_HWACCEL_COPYAREA 0x0100 /* required 需要*/
#define FBINFO_HWACCEL_FILLRECT 0x0200 /* required 需要*/
#define FBINFO_HWACCEL_IMAGEBLIT 0x0400 /* required 需要*/
#define FBINFO_HWACCEL_ROTATE 0x0800 /* optional 可选*/
#define FBINFO_HWACCEL_XPAN 0x1000 /* optional 可选*/
#define FBINFO_HWACCEL_YPAN 0x2000 /* optional */
#define FBINFO_HWACCEL_YWRAP 0x4000 /* optional */

#define FBINFO_MISC_USEREVENT 0x10000 /* event request　
                          from userspace 从用户空间时间需要*/
#define FBINFO_MISC_TILEBLITTING 0x20000 /* use tile blitting 使用tile blitting*/
#define FBINFO_MISC_FIRMWARE 0x40000 /* a replaceable firmware
                          inited framebuffer 一个可替换的固件初始化的framebuffer*/

/* A driver may set this flag to indicate that it does want a set_par to be * called every time when fbcon_switch is executed. The advantage is that with * this flag set you can really be sure that set_par is always called before * any of the functions dependant on the correct hardware state or altering * that state, even if you are using some broken X releases. The disadvantage * is that it introduces unwanted delays to every console switch if set_par * is slow. It is a good idea to try this flag in the drivers initialization * code whenever there is a bug report related to switching between X and the * framebuffer console. * 一个驱动可能会设置这个标识来表明每次当fbcon_switch被执行的时候，他不想调用set_par()． *　他的优点就是伴随着这个标识的设置，你可以确定set_par在任何依赖于正确的硬件状态 *　或者是改变那个状态之前被一直调用，即使你整在使用一些x发行版．他的缺点就是如果 *　set_par太慢的话，在显示在每一个控制台的时候，会导致不希望的延迟． * * */
#define FBINFO_MISC_ALWAYS_SETPAR 0x40000

/* * Host and GPU endianness differ. 　* 主机和GPU端不同 */
#define FBINFO_FOREIGN_ENDIAN 0x100000
/* * Big endian math. This is the same flags as above, but with different * meaning, it is set by the fb subsystem depending FOREIGN_ENDIAN flag * and host endianness. Drivers should not use this flag. * 大端数学．这个是和上面一样的标识，但是意义却是不一样的，他是被依赖于FOREIGN_ENDIAN端 *　和主机端的fb子系统所设置的．驱动不应该使用这个标识 * */
#define FBINFO_BE_MATH 0x100000

struct fb_info {
    int node;
    int flags;
    struct mutex lock;      /* Lock for open/release/ioctl funcs 用于open/release/ioctl函数的锁　*/
    struct mutex mm_lock;       /* Lock for fb_mmap and smem_* fields 用于fb_mmap和smem_* 域的锁　*/
    struct fb_var_screeninfo var;   /* Current var 可变参数*/
    struct fb_fix_screeninfo fix;   /* Current fix 固定参数　*/
    struct fb_monspecs monspecs;    /* Current Monitor specs 　显示器标准　*/
    struct work_struct queue;   /* Framebuffer event queue 帧缓冲事件队列　*/
    struct fb_pixmap pixmap;    /* Image hardware mapper 图像硬件mapper */
    struct fb_pixmap sprite;    /* Cursor hardware mapper 光标硬件mapper */
    struct fb_cmap cmap;        /* Current cmap 目前的颜色表　*/
    struct list_head modelist;      /* mode list 模式列表　*/
    struct fb_videomode *mode;  /* current mode 当前的video模式　*/

#ifdef CONFIG_FB_BACKLIGHT
    /* assigned backlight device 对应的背光设备*/
    /* set before framebuffer registration, remove after unregister 在framebuffer注册之前被设置，在注销之后移走　*/
    struct backlight_device *bl_dev;

    /* Backlight level curve 背光调整　*/
    struct mutex bl_curve_mutex;    
    u8 bl_curve[FB_BACKLIGHT_LEVELS];
#endif
#ifdef CONFIG_FB_DEFERRED_IO
    struct delayed_work deferred_work;
    struct fb_deferred_io *fbdefio;
#endif

    struct fb_ops *fbops;  //　帧缓冲操作
    struct device *device;      /* This is the parent 辐射被*/
    struct device *dev;     /* This is this fb device fb设备　*/
    int class_flag;                    /* private sysfs flags 私有sysfs标识 */
#ifdef CONFIG_FB_TILEBLITTING
    struct fb_tile_ops *tileops;    /* Tile Blitting 图块blitting */
#endif
    char __iomem *screen_base;  /* Virtual address 虚拟基地址　*/
    unsigned long screen_size;  /* Amount of ioremapped VRAM or 0 ioremapped的虚拟内存大小　或者是　０*/ 
    void *pseudo_palette;       /* Fake palette of 16 colors 伪１６色颜色表　　*/ 
#define FBINFO_STATE_RUNNING 0
#define FBINFO_STATE_SUSPENDED 1
    u32 state;          /* Hardware state i.e suspend 硬件状态，如挂起　*/
    void *fbcon_par;                /* fbcon use-only private area fbcon仅仅用于私有区域*/
    /* From here on everything is device dependent 从这里开始所有的事物都是设备依赖的　*/
    void *par;
    /* we need the PCI or similiar aperture base/size not smem_start/size as smem_start may just be an object allocated inside the aperture so may not actually overlap */
    resource_size_t aperture_base;
    resource_size_t aperture_size;
};

#ifdef MODULE
#define FBINFO_DEFAULT FBINFO_MODULE
#else
#define FBINFO_DEFAULT 0
#endif

// This will go away　这将会走开
#define FBINFO_FLAG_MODULE FBINFO_MODULE
#define FBINFO_FLAG_DEFAULT FBINFO_DEFAULT

/* This will go away * fbset currently hacks in FB_ACCELF_TEXT into var.accel_flags * when it wants to turn the acceleration engine on. This is * really a separate operation, and should be modified via sysfs. * But for now, we leave it broken with the following define * 这将会走开．当他想要打开加速引擎的时候，fbset会到var.accel_falgs. *　这个事实上是一个分离的操作，并且应该有sysfs修改．但是，对于现在来说， *　　我们把他打破与下面的定义． */
#define STUPID_ACCELF_TEXT_SHIT

// This will go away
// 这个将走开
#if defined(__sparc__)

/* We map all of our framebuffers such that big-endian accesses * are what we want, so the following is sufficient. 　* * 我们映射所有的framebuffers，例如大端访问是我们需要的，所以下面的就足够了 */

// This will go away
#define fb_readb sbus_readb
#define fb_readw sbus_readw
#define fb_readl sbus_readl
#define fb_readq sbus_readq
#define fb_writeb sbus_writeb
#define fb_writew sbus_writew
#define fb_writel sbus_writel
#define fb_writeq sbus_writeq
#define fb_memset sbus_memset_io

#elif defined(__i386__) || defined(__alpha__) || defined(__x86_64__) || defined(__hppa__) || defined(__sh__) || defined(__powerpc__) || defined(__avr32__) || defined(__bfin__)

#define fb_readb __raw_readb
#define fb_readw __raw_readw
#define fb_readl __raw_readl
#define fb_readq __raw_readq
#define fb_writeb __raw_writeb
#define fb_writew __raw_writew
#define fb_writel __raw_writel
#define fb_writeq __raw_writeq
#define fb_memset memset_io

#else

#define fb_readb(addr) (*(volatile u8 *) (addr))
#define fb_readw(addr) (*(volatile u16 *) (addr))
#define fb_readl(addr) (*(volatile u32 *) (addr))
#define fb_readq(addr) (*(volatile u64 *) (addr))
#define fb_writeb(b,addr) (*(volatile u8 *) (addr) = (b))
#define fb_writew(b,addr) (*(volatile u16 *) (addr) = (b))
#define fb_writel(b,addr) (*(volatile u32 *) (addr) = (b))
#define fb_writeq(b,addr) (*(volatile u64 *) (addr) = (b))
#define fb_memset memset

#endif

#define FB_LEFT_POS(p, bpp) (fb_be_math(p) ? (32 - (bpp)) : 0)
#define FB_SHIFT_HIGH(p, val, bits) (fb_be_math(p) ? (val) >> (bits) : \
                              (val) << (bits))
#define FB_SHIFT_LOW(p, val, bits) (fb_be_math(p) ? (val) << (bits) : \
                              (val) >> (bits))

    /* * `Generic' versions of the frame buffer device operations * framebuffer的'Generis'版本的设备操作 * */

extern int fb_set_var(struct fb_info *info, struct fb_var_screeninfo *var); 
extern int fb_pan_display(struct fb_info *info, struct fb_var_screeninfo *var); 
extern int fb_blank(struct fb_info *info, int blank);
extern void cfb_fillrect(struct fb_info *info, const struct fb_fillrect *rect); 
extern void cfb_copyarea(struct fb_info *info, const struct fb_copyarea *area); 
extern void cfb_imageblit(struct fb_info *info, const struct fb_image *image);
/* * Drawing operations where framebuffer is in system RAM * 在framebuffer所在的系统RAM绘制操作 * */
extern void sys_fillrect(struct fb_info *info, const struct fb_fillrect *rect);
extern void sys_copyarea(struct fb_info *info, const struct fb_copyarea *area);
extern void sys_imageblit(struct fb_info *info, const struct fb_image *image);
extern ssize_t fb_sys_read(struct fb_info *info, char __user *buf,
               size_t count, loff_t *ppos);
extern ssize_t fb_sys_write(struct fb_info *info, const char __user *buf,
                size_t count, loff_t *ppos);

/* drivers/video/fbmem.c */
extern int register_framebuffer(struct fb_info *fb_info);
extern int unregister_framebuffer(struct fb_info *fb_info);
extern int fb_prepare_logo(struct fb_info *fb_info, int rotate);
extern int fb_show_logo(struct fb_info *fb_info, int rotate);
extern char* fb_get_buffer_offset(struct fb_info *info, struct fb_pixmap *buf, u32 size);
extern void fb_pad_unaligned_buffer(u8 *dst, u32 d_pitch, u8 *src, u32 idx,
                u32 height, u32 shift_high, u32 shift_low, u32 mod);
extern void fb_pad_aligned_buffer(u8 *dst, u32 d_pitch, u8 *src, u32 s_pitch, u32 height);
extern void fb_set_suspend(struct fb_info *info, int state);
extern int fb_get_color_depth(struct fb_var_screeninfo *var,
                  struct fb_fix_screeninfo *fix);
extern int fb_get_options(char *name, char **option);
extern int fb_new_modelist(struct fb_info *info);

extern struct fb_info *registered_fb[FB_MAX];
extern int num_registered_fb;
extern struct class *fb_class;

extern int lock_fb_info(struct fb_info *info);

static inline void unlock_fb_info(struct fb_info *info)
{
    mutex_unlock(&info->lock);
}

static inline void __fb_pad_aligned_buffer(u8 *dst, u32 d_pitch,
                       u8 *src, u32 s_pitch, u32 height)
{
    int i, j;

    d_pitch -= s_pitch;

    for (i = height; i--; ) {
        /* s_pitch is a few bytes at the most, memcpy is suboptimal */
        for (j = 0; j < s_pitch; j++)
            *dst++ = *src++;
        dst += d_pitch;
    }
}

/* drivers/video/fb_defio.c */
extern void fb_deferred_io_init(struct fb_info *info);
extern void fb_deferred_io_open(struct fb_info *info,
                struct inode *inode,
                struct file *file);
extern void fb_deferred_io_cleanup(struct fb_info *info);
extern int fb_deferred_io_fsync(struct file *file, struct dentry *dentry,
                int datasync);

static inline bool fb_be_math(struct fb_info *info)
{
#ifdef CONFIG_FB_FOREIGN_ENDIAN
#if defined(CONFIG_FB_BOTH_ENDIAN)
    return info->flags & FBINFO_BE_MATH;
#elif defined(CONFIG_FB_BIG_ENDIAN)
    return true;
#elif defined(CONFIG_FB_LITTLE_ENDIAN)
    return false;
#endif /* CONFIG_FB_BOTH_ENDIAN */
#else
#ifdef __BIG_ENDIAN
    return true;
#else
    return false;
#endif /* __BIG_ENDIAN */
#endif /* CONFIG_FB_FOREIGN_ENDIAN */
}

/* drivers/video/fbsysfs.c */
extern struct fb_info *framebuffer_alloc(size_t size, struct device *dev);
extern void framebuffer_release(struct fb_info *info);
extern int fb_init_device(struct fb_info *fb_info);
extern void fb_cleanup_device(struct fb_info *head);
extern void fb_bl_default_curve(struct fb_info *fb_info, u8 off, u8 min, u8 max);

/* drivers/video/fbmon.c */
#define FB_MAXTIMINGS 0
#define FB_VSYNCTIMINGS 1
#define FB_HSYNCTIMINGS 2
#define FB_DCLKTIMINGS 3
#define FB_IGNOREMON 0x100

#define FB_MODE_IS_UNKNOWN 0
#define FB_MODE_IS_DETAILED 1
#define FB_MODE_IS_STANDARD 2
#define FB_MODE_IS_VESA 4
#define FB_MODE_IS_CALCULATED 8
#define FB_MODE_IS_FIRST 16
#define FB_MODE_IS_FROM_VAR 32

extern int fbmon_dpms(const struct fb_info *fb_info);
extern int fb_get_mode(int flags, u32 val, struct fb_var_screeninfo *var,
               struct fb_info *info);
extern int fb_validate_mode(const struct fb_var_screeninfo *var,
                struct fb_info *info);
extern int fb_parse_edid(unsigned char *edid, struct fb_var_screeninfo *var);
extern const unsigned char *fb_firmware_edid(struct device *device);
extern void fb_edid_to_monspecs(unsigned char *edid,
                struct fb_monspecs *specs);
extern void fb_destroy_modedb(struct fb_videomode *modedb);
extern int fb_find_mode_cvt(struct fb_videomode *mode, int margins, int rb);
extern unsigned char *fb_ddc_read(struct i2c_adapter *adapter);

/* drivers/video/modedb.c */
#define VESA_MODEDB_SIZE 34
extern void fb_var_to_videomode(struct fb_videomode *mode,
                const struct fb_var_screeninfo *var);
extern void fb_videomode_to_var(struct fb_var_screeninfo *var,
                const struct fb_videomode *mode);
extern int fb_mode_is_equal(const struct fb_videomode *mode1,
                const struct fb_videomode *mode2);
extern int fb_add_videomode(const struct fb_videomode *mode,
                struct list_head *head);
extern void fb_delete_videomode(const struct fb_videomode *mode,
                struct list_head *head);
extern const struct fb_videomode *fb_match_mode(const struct fb_var_screeninfo *var,
                        struct list_head *head);
extern const struct fb_videomode *fb_find_best_mode(const struct fb_var_screeninfo *var,
                            struct list_head *head);
extern const struct fb_videomode *fb_find_nearest_mode(const struct fb_videomode *mode,
                               struct list_head *head);
extern void fb_destroy_modelist(struct list_head *head);
extern void fb_videomode_to_modelist(const struct fb_videomode *modedb, int num,
                     struct list_head *head);
extern const struct fb_videomode *fb_find_best_display(const struct fb_monspecs *specs,
                               struct list_head *head);

/* drivers/video/fbcmap.c */
extern int fb_alloc_cmap(struct fb_cmap *cmap, int len, int transp);
extern void fb_dealloc_cmap(struct fb_cmap *cmap);
extern int fb_copy_cmap(const struct fb_cmap *from, struct fb_cmap *to);
extern int fb_cmap_to_user(const struct fb_cmap *from, struct fb_cmap_user *to);
extern int fb_set_cmap(struct fb_cmap *cmap, struct fb_info *fb_info);
extern int fb_set_user_cmap(struct fb_cmap_user *cmap, struct fb_info *fb_info);
extern const struct fb_cmap *fb_default_cmap(int len);
extern void fb_invert_cmaps(void);

struct fb_videomode {
    const char *name;   /* optional */
    u32 refresh;        /* optional */
    u32 xres;
    u32 yres;
    u32 pixclock;
    u32 left_margin;
    u32 right_margin;
    u32 upper_margin;
    u32 lower_margin;
    u32 hsync_len;
    u32 vsync_len;
    u32 sync;
    u32 vmode;
    u32 flag;
};

extern const char *fb_mode_option;
extern const struct fb_videomode vesa_modes[];

struct fb_modelist {
    struct list_head list;
    struct fb_videomode mode;
};

extern int fb_find_mode(struct fb_var_screeninfo *var,
            struct fb_info *info, const char *mode_option,
            const struct fb_videomode *db,
            unsigned int dbsize,
            const struct fb_videomode *default_mode,
            unsigned int default_bpp);

#endif /* __KERNEL__ */

#endif /* _LINUX_FB_H */