分类： 嵌入式
2011-05-02 22:12:39
还是要补充点，下面是/linux/fb.h的部分注释，加粗的是常用的，红色是关键的，一般不可少。旁边没有汉字，要么很简单没必要加注，要么就用不到！
注释：
#ifndef _LINUX_FB_H
#define _LINUX_FB_H
#include
#include
/* Definitions of frame buffers */
#define FB_MAJOR 29 /*主设备号*/
#define FB_MAX 32 /* sufficient for now */
/* 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
/* 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 */
#define FB_TYPE_PLANES 1 /* Non interleaved planes */
#define FB_TYPE_INTERLEAVED_PLANES 2 /* Interleaved planes */
#define FB_TYPE_TEXT 3 /* Text/attributes */
#define FB_TYPE_VGA_PLANES 4 /* EGA/VGA planes */
#define FB_AUX_TEXT_MDA 0 /* Monochrome text */
#define FB_AUX_TEXT_CGA 1 /* CGA/EGA/VGA Color text */
#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_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 */
#define FB_VISUAL_MONO10 1 /* Monochr. 1=White 0=Black */
#define FB_VISUAL_TRUECOLOR 2 /* True color */
#define FB_VISUAL_PSEUDOCOLOR 3 /* Pseudo color (like atari) */
#define FB_VISUAL_DIRECTCOLOR 4 /* Direct color */
#define FB_VISUAL_STATIC_PSEUDOCOLOR 5 /* Pseudo color readonly */
#define FB_ACCEL_NONE 0 /* no hardware accelerator */
#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 */
/*上面的宏定义不用关心*/
/*不可修改的屏幕信息，用户空间可见*/
struct fb_fix_screeninfo {
char id[16]; /* identification string eg "TT Builtin" */
unsigned long smem_start; /* Start of frame buffer mem 显存的起始地址*/
/* (physical address) */
__u32 smem_len; /* Length of frame buffer mem 显存的大小 */
__u32 type; /* see FB_TYPE_* */
__u32 type_aux; /* Interleave for interleaved Planes */
__u32 visual; /* see FB_VISUAL_* */
__u16 xpanstep; /* zero if no hardware panning */
__u16 ypanstep; /* zero if no hardware panning */
__u16 ywrapstep; /* zero if no hardware ywrap */
__u32 line_length; /* length of a line in bytes 每行的字节数 */
unsigned long mmio_start; /* Start of Memory Mapped I/O */
/* (physical address) */
__u32 mmio_len; /* Length of Memory Mapped I/O */
__u32 accel; /* Type of acceleration available */
__u16 reserved[3]; /* Reserved for future compatibility */
};
/* 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. This implies
* big-endian byte order if bits_per_pixel is greater than 8.
*/
/*像素所占字节内，各个颜色的位分配比如RGB=888,565,555等等，*/
struct fb_bitfield {
__u32 offset; /* beginning of bitfield */
__u32 length; /* length of bitfield */
__u32 msb_right; /* != 0 : Most significant bit is */
/* right */
};
/*下面的宏也不常用*/
#define FB_NONSTD_HAM 1 /* Hold-And-Modify (HAM) */
#define FB_ACTIVATE_NOW 0 /* set values immediately (or vbl)*/
#define FB_ACTIVATE_NXTOPEN 1 /* activate on next open */
#define FB_ACTIVATE_TEST 2 /* don't set, round up impossible */
#define FB_ACTIVATE_MASK 15
/* values */
#define FB_ACTIVATE_VBL 16 /* activate values on next vbl */
#define FB_CHANGE_CMAP_VBL 32 /* change colormap on vbl */
#define FB_ACTIVATE_ALL 64 /* change all VCs on this fb */
#define FB_ACCELF_TEXT 1 /* text mode acceleration */
#define FB_SYNC_HOR_HIGH_ACT 1 /* horizontal sync high active */
#define FB_SYNC_VERT_HIGH_ACT 2 /* vertical sync high active */
#define FB_SYNC_EXT 4 /* external sync */
#define FB_SYNC_COMP_HIGH_ACT 8 /* composite sync high active */
#define FB_SYNC_BROADCAST 16 /* broadcast video timings
下图会向你展示目前的framebuffer设备驱动的结构，最常用的是非标准驱动。很明显他所处的层次最高，程序编写是最容易的。理解了这个图的，你已经很轻松的去完成一个fb驱动，比如给sa1100,s2410,s2440系列的ARM的LCD控制器写驱动。
