用QT210 LDD平台運行《Linux設備驅動開發詳解》實例

QT210 LDD開發平台采用Samsung S5PV210，基於CortexTM-A8，運行主頻1GHz，內置PowerVR SGX540高性能圖形引擎，最高可支持1080p@30fps硬件解碼視頻流暢播放，格式可為MPEG4, H.263, H.264等。

QT210默認運行Android 2.3，是LDD6410硬件軟件的全面升級。下面我們以3個case為例看看如何以QT210 LDD平台運行《Linux設備驅動開發詳解》的實例(http://www.linuxidc.com/Linux/2011-07/38211.htm)。

1. framebuffer測試程序

該測試程序在lcd上繪制r,g,b3個逐漸變化的彩帶，程序源代碼如下：

1. /*
2. * LDD6410 framebuffer test programs
3. * Copyright 2011 www.linuxidc.com
4. */
5. #include <unistd.h>
6. #include <stdlib.h>
7. #include <stdio.h>
8. #include <fcntl.h>
9. #include <linux/fb.h>
10. #include <sys/mman.h>
12. int main()
13. {
14. int fbfd = 0;
15. struct fb_var_screeninfo vinfo;
16. unsigned long screensize = 0;
17. char *fbp = 0;
18. int x = 0, y = 0;
19. int i = 0;
21. // Open the file for reading and writing
22. fbfd = open("/dev/graphics/fb0", O_RDWR);
23. if (!fbfd) {
24. printf("Error: cannot open framebuffer device.\n");
25. exit(1);
26. }
27. printf("The framebuffer device was opened successfully.\n");
29. // Get variable screen information
30. if (ioctl(fbfd, FBIOGET_VSCREENINFO, &vinfo)) {
31. printf("Error reading variable information.\n");
32. exit(1);
33. }
35. printf("%dx%d, %dbpp\n", vinfo.xres, vinfo.yres, vinfo.bits_per_pixel);
36. if (vinfo.bits_per_pixel != 16 && vinfo.bits_per_pixel != 32) {
37. printf("Error: not supported bits_per_pixel, it only supports 16/32 bit color\n");
38. }
40. // Figure out the size of the screen in bytes
41. screensize = vinfo.xres * vinfo.yres * (vinfo.bits_per_pixel / 8);
43. // Map the device to memory
44. fbp = (char *)mmap(0, screensize, PROT_READ | PROT_WRITE, MAP_SHARED,
45. fbfd, 0);
46. if ((int)fbp == -1) {
47. printf("Error: failed to map framebuffer device to memory.\n");
48. exit(4);
49. }
50. printf("The framebuffer device was mapped to memory successfully.\n");
52. // Draw 3 rect with graduated RED/GREEN/BLUE
53. for (i = 0; i < 3; i++) {
54. for (y = i * (vinfo.yres / 3); y < (i + 1) * (vinfo.yres / 3); y++) {
55. for (x = 0; x < vinfo.xres; x++) {
56. long location = x * 2 + y * vinfo.xres * 2;
57. int r = 0, g = 0, b = 0;
59. if (vinfo.bits_per_pixel == 16) {
60. unsigned short rgb;
62. if (i == 0)
63. r = ((x * 1.0) / vinfo.xres) * 32;
64. if (i == 1)
65. g = ((x * 1.0) / vinfo.xres) * 64;
66. if (i == 2)
67. b = ((x * 1.0) / vinfo.xres) * 32;
69. rgb = (r << 11) | (g << 5) | b;
70. *((unsigned short*)(fbp + location)) = rgb;
71. } else {
72. location = location * 2;
73. unsigned int rgb;
75. if (i == 0)
76. r = ((x * 1.0) / vinfo.xres) * 256;
77. if (i == 1)
78. g = ((x * 1.0) / vinfo.xres) * 256;
79. if (i == 2)
80. b = ((x * 1.0) / vinfo.xres) * 256;
82. rgb = (r << 16) | (g << 8) | b;
83. *((unsigned int*)(fbp + location)) = rgb;
84. }
85. }
86. }
87. }
89. munmap(fbp, screensize);
90. close(fbfd);
91. return 0;
92. }