七、在U-boot中让LCD显示图片

1. 增加Nandflash读取代码

　　因为要显示图片，而图片明显是放在Nandflash中比较合适，因此需要有能够操作Nandflash的函数。在U-boot中已经有能操作Nandflash的函数了，但是我找了半天也不知道该怎么调用，因此还是上自己的代码吧。

 #define NFCONF *(volatile unsigned int *)0x70200000
 #define NFCONT *(volatile unsigned int *)0x70200004
 #define NFCMMD *(volatile unsigned char *)0x70200008
 #define NFADDR *(volatile unsigned int *)0x7020000c
 #define NFDATA *(volatile unsigned char *)0x70200010
 #define NFSTAT *(volatile unsigned int *)0x70200028
 #define NAND_SECTOR_SIZE 2048
 #define NAND_BLOCK_MASK (NAND_SECTOR_SIZE - 1)

 #define TACLS   7
 #define TWRPH0  7
 #define TWRPH1  7

 /**
  * \brief Nandflash初始化
  */
 static void __nand_init(void)
 {
     NFCONF = (TACLS<<) | (TWRPH0<<) | (TWRPH1<<);
     NFCONT = (<<) | (<<) | ();
 }

 static void __nand_select(void)
 {
     NFCONT &= ~(<<);
 }

 static void __nand_deselect(void)
 {
     NFCONT |= (<<);
 }

 static void __nand_cmd(unsigned char cmd)
 {
     NFCMMD = cmd;
 }

 static void __nand_addr (unsigned int addr)
 {
     unsigned int col = addr&NAND_BLOCK_MASK;
     unsigned int page = addr/NAND_SECTOR_SIZE;

     NFADDR = col & 0xff;
     NFADDR = (col>>) & 0xff;
     NFADDR = page & 0xff;
     NFADDR = (page >> ) & 0xff;
     NFADDR = (page >> ) & 0x3;
 }

 static void __nand_wait_teady(void)
 {
     int i;
     while (!(NFSTAT & ))
         for (i = ; i < ; i++);
 }

 static unsigned char __nand_data(void)
 {
     unsigned char p;
     p = NFDATA;
     return p;
 }

 /**
  * \brief 从Nandflash中读取数据至内存中
  */
 static void __nand_read (unsigned int addr, unsigned char *buf, unsigned int len)
 {
     int col = addr % ;
     int i = ;
     __nand_select();
     while (i < len) {
         __nand_cmd();
         __nand_addr(addr);
         __nand_cmd(0x30);
         __nand_wait_teady();

         for (; col < &&(i < len); col++) {
             buf[i] = __nand_data();
             i++;
             addr++;
         }
         col = ;
     }
     __nand_deselect();
 }

 static void __nand_reset(void)
 {
     __nand_select();
     __nand_cmd(0xff);
     __nand_wait_teady();
     __nand_deselect();
 }

 /**
  * \brief 将Nandflash中的内容读取至内存
  */
 void nand_copy2ram(unsigned int addr, unsigned char *buff, unsigned int len)
 {
     //__nand_init();
     __nand_reset();
     __nand_read(addr, buff, len);
 }

　　注意第101行我把__nand_init注释掉了，因为U-boot起来之后肯定已经对Nandflash初始化过了。

2. 修改LCD代码

　　lcd.c

 #include "lcd.h"

 static int PEN_COLOR = LCD_RED;     /* 定义画笔（前景）颜色 */
 static int BK_COLOR  = LCD_BLACK;   /* 定义背景颜色 */

 /**
  * \brief LCD初始化
  */
 void lcd_init (void)
 {
     GPICON = ;
     GPICON |= 0xaaaaaaaa;
     GPJCON = ;
     GPJCON |= 0xaaaaaa;

     MIFPCON &= ~(0x1<<);
     SPCON &= ~0x3;
     SPCON |= 0x1;

     VIDCON0 = (<<) | (0x1<<) | (0x3);
     VIDCON1 = (0x1<) | (0x1<<);

     VIDTCON0 = (<<) | (<<) | ();
     VIDTCON1 = (<<) | (<<) | ();

     VIDTCON2 = ((LCD_HEIGHT - ) << ) | (LCD_WIDTH - );
     WINCON0 = (0xb<<) | (0x1);

     VIDOSD0A = ;
     VIDOSD0B = ((LCD_WIDTH - ) << ) | ((LCD_HEIGHT - ));

     VIDOSD0C = LCD_WIDTH * LCD_HEIGHT;

     VIDW00ADD0B0 = SHOW_BUF;
 }

 /**
  * \brief 设置画笔颜色
  */
 void lcd_set_pen_color (int color)
 {
     PEN_COLOR = color;
 }

 /**
  * \brief 设置背景颜色
  */
 void lcd_set_bk_color (int color)
 {
     BK_COLOR = color;
 }

 /**
  * \brief 绘制一个点
  */
 void lcd_draw_point (int x, int y)
 {
     *((int *)SHOW_BUF + x + y * LCD_WIDTH) = PEN_COLOR;
 }

 void lcd_draw_bk (int x, int y)
 {
     *((int *)SHOW_BUF + x + y * LCD_WIDTH) = BK_COLOR;
 }

 /**
  * \brief 清屏（填充背景色）
  */
 void lcd_clean (void)
 {
     int i, j;
     for(i=; i<LCD_HEIGHT; i++) {
         for(j=; j<LCD_WIDTH; j++) {
             lcd_draw_bk(j, i);
         }
     }
 }

 /**
  * \brief 显示一张BMP图片
  */
 void lcd_show_bmp (int x , int y , unsigned char *pic)
 {
     col_t c;
     BITMAPFILEHEADER filehead;
     BITMAPINFOHEADER infohead;
     int i, j;
     unsigned char *p = ;
     int width_error = ;
     int old_pen_color;

     memcpy(&filehead , pic, sizeof(filehead));
     memcpy(&infohead , pic + sizeof(filehead), sizeof(infohead));

     width_error = ( - infohead.biWidth *  % ) % ;

     p = pic + sizeof(filehead) + sizeof(infohead);

     old_pen_color = PEN_COLOR;

     c.c.non = ;
     for (j = infohead.biHeight-; j>=; j--) {
         for (i = ; i < infohead.biWidth; i++) {
             c.c.b = *p++;
             c.c.g = *p++;
             c.c.r = *p++;

             PEN_COLOR = c.l;
             lcd_draw_point(x + i, y + j);
         }
         p += width_error;
     }
     PEN_COLOR = old_pen_color;
 }

　　lcd.h

 #ifndef __LCD_H
 #define __LCD_H

 /* 定义寄存器地址 */
 #define GPICON  (*(unsigned int *)0x7F008100)
 #define SPCON   (*(unsigned int *)0x7F0081A0)
 #define MIFPCON (*(unsigned int *)0x7410800c)
 #define GPJCON  (*(unsigned int *)0x7F008120)

 #define VIDCON0       (*(unsigned int *)0x77100000)
 #define VIDCON1       (*(unsigned int *)0x77100004)
 #define VIDCON2       (*(unsigned int *)0x77100008)
 #define VIDTCON0      (*(unsigned int *)0x77100010)
 #define VIDTCON1      (*(unsigned int *)0x77100014)
 #define VIDTCON2      (*(unsigned int *)0x77100018)
 #define WINCON0       (*(unsigned int *)0x77100020)
 #define WINCON1       (*(unsigned int *)0x77100024)
 #define WINCON2       (*(unsigned int *)0x77100028)
 #define WINCON3       (*(unsigned int *)0x7710002C)
 #define WINCON4       (*(unsigned int *)0x77100030)
 #define VIDOSD0A      (*(unsigned int *)0x77100040)
 #define VIDOSD0B      (*(unsigned int *)0x77100044)
 #define VIDOSD0C      (*(unsigned int *)0x77100048)
 #define VIDOSD1A      (*(unsigned int *)0x77100050)
 #define VIDOSD1B      (*(unsigned int *)0x77100054)
 #define VIDOSD1C      (*(unsigned int *)0x77100058)
 #define VIDW00ADD0B0  (*(unsigned int *)0x771000A0)
 #define GPECON        (*(unsigned int *)0x7f008080)
 #define GPEDAT        (*(unsigned int *)0x7f008084)

 #define LCD_WIDTH   480     /* 定义LCD宽度 */
 #define LCD_HEIGHT  272     /* 定义LCD高度 */

 /* 定义显存地址 */
 #define SHOW_BUF 0x54000000

 /* 定义常用颜色 */
 #define COL(R,G,B)   ((R<<16) | (G<<8) | (B))
 #define LCD_RED          COL(0xFF, 0, 0)
 #define LCD_GREEN     COL(0, 0xFF, 0)
 #define LCD_BLUE      COL(0, 0, 0xFF)
 #define LCD_WHITE     COL(0xFF, 0xFF, 0xFF)
 #define LCD_BLACK     COL(0, 0, 0)

 typedef unsigned short WORD;
 typedef unsigned char BYTE;
 typedef unsigned int DWORD;
 typedef int LONG; 

 #pragma pack(2)
 typedef struct tagBITMAPFILEHEADER
 {
     WORD bfType;            // 位图文件的类型，必须为BM
     DWORD bfSize;           // 位图文件的大小，以字节为单位
     WORD bfReserved1;       // 位图文件保留字，必须为0
     WORD bfReserved2;       // 位图文件保留字，必须为0
     DWORD bfOffBits;        // 位图数据的起始位置，以相对于位图
     // 文件头的偏移量表示，以字节为单位
 } BITMAPFILEHEADER;

 typedef struct tagBITMAPINFOHEADER
 {
     DWORD biSize;           // 本结构所占用字节数
     LONG biWidth;           // 位图的宽度，以像素为单位
     LONG biHeight;          // 位图的高度，以像素为单位
     WORD biPlanes;          // 目标设备的级别，必须为1
     WORD biBitCount;        // 每个像素所需的位数，必须是1(双色),
          // 4(16色)，8(256色)或24(真彩色)之一
     DWORD biCompression;    // 位图压缩类型，必须是 0(不压缩),
         // 1(BI_RLE8压缩类型)或2(BI_RLE4压缩类型)之一
     DWORD biSizeImage;      // 位图的大小，以字节为单位
     LONG biXPelsPerMeter;   // 位图水平分辨率，每米像素数
     LONG biYPelsPerMeter;   // 位图垂直分辨率，每米像素数
     DWORD biClrUsed;        // 位图实际使用的颜色表中的颜色数
     DWORD biClrImportant;   // 位图显示过程中重要的颜色数
 } BITMAPINFOHEADER;
 #pragma pack(4)

 struct _rgb_
 {
     unsigned char b;
     unsigned char g;
     unsigned char r;
     unsigned char non;
 };

 typedef union _color_
 {
     struct _rgb_ c;
     unsigned int l;
 } col_t;

 /******************************* 函数声明 **************************/
 /**
  * \brief LCD初始化
  */
 extern void lcd_init (void);

 /**
  * \brief 设置画笔颜色
  */
 extern void lcd_set_pen_color (int color);

 /**
  * \brief 设置背景颜色
  */
 extern void lcd_set_bk_color (int color);

 /**
  * \brief 绘制一个点
  */
 extern void lcd_draw_point (int x, int y);

 /**
  * \brief 清屏（填充背景色）
  */
 extern void lcd_clean (void);

 /**
  * \brief 显示一张BMP图片
  */
 extern void lcd_show_bmp (int x , int y , unsigned char *pic);

 #endif

3. 修改board.c和Makefile

　　去掉原先填充纯色的代码，改为显示图片的代码：

　　nand_copy2ram第一个参数为Nandflash中要读取的地址，在这里我写的是0x100000，因此运行程序前需要保证该地址有我想要的图片；第二个参数为内存地址，需要与保证其他程序不会使用该地址，且与lcd_show_bmp传入的地址相同；第三个参数为拷贝数据大小，一张480*272的24位图大小不会超过400K，这里传入0x80000足够了。

　　此外还要修改lib_arm下的Makefile，在COBJS后面加上nand.o后编译。

4. 下载程序

　　编译成功后在U-boot中将新编译出的U-boot下载进Nandflash的0地址，将BMP图片下载到0x100000地址。重启开发板，能看到LCD上显示出图片。