S3C6410 LCD驱动分析（转）
一. 理论分析
1. 几个概念:
FIMC :
Fully Interactive Mobile Camera （完全交互式移动摄像机）
FIMD:
Fully Interactive Mobile Display （完全交互式移动显示设备）
2. 设置VCLK
在VIDCON0中
bit[3:2]-->Select the Video Clock source =00 --> HCLK=133MHZ
bit[13:6] --> CLKVAL_F = 13 (这个值是在驱动中计算出来的)
VCLK = Video Clock Source / (CLKVAL+1) where CLKVAL >= 1
= 133MHZ / (13+1) = 9.5MHZ
3. 刷新频率计算
Frame Rate = VCLK / (HSPW + HBPD + HOZVAL + HFPD) / (VSPW + VBPD + LINEVAL + VFPD)
= 9.5MHZ/(2+41+2+480)/(2+272+10+2)
=0.00006327MHZ
=63HZ
二. 驱动分析
首先在平台的目录中定义platform_device
在arch/arm/plat-samsung/dev-fb.c中
1 static struct resource s3c_fb_resource[] = {
2 [0] = {
3 .start = S3C_PA_FB,
4 .end = S3C_PA_FB + SZ_16K - 1,
5 .flags = IORESOURCE_MEM,
6 },
7 [1] = {
8 .start = IRQ_LCD_VSYNC,
9 .end = IRQ_LCD_VSYNC,
10 .flags = IORESOURCE_IRQ,
11 },
12 [2] = {
13 .start = IRQ_LCD_FIFO,
14 .end = IRQ_LCD_FIFO,
15 .flags = IORESOURCE_IRQ,
16 },
17 [3] = {
18 .start = IRQ_LCD_SYSTEM,
19 .end = IRQ_LCD_SYSTEM,
20 .flags = IORESOURCE_IRQ,
21 },
22 };
23
24 struct platform_device s3c_device_fb = {
25 .name = "s3c-fb",
26 .id = -1,
27 .num_resources = ARRAY_SIZE(s3c_fb_resource),
28 .resource = s3c_fb_resource,
29 .dev.dma_mask = &s3c_device_fb.dev.coherent_dma_mask,
30 .dev.coherent_dma_mask = 0xffffffffUL,
31 };
然后在驱动的probe函数中:
在driver/video/samsun/s3cfb.c中
1 static int __init s3cfb_probe(struct platform_device *pdev)
2 {
3 struct resource *res;
4 struct fb_info *fbinfo;
5 s3cfb_info_t *info;
6
7 char driver_name[] = "s3cfb";
8 int index = 0, ret, size;
9 //分配sizeof(fb_info+私有成员)大小的内存,使par指向s3cfb_info_t结构体
10 fbinfo = framebuffer_alloc(sizeof(s3cfb_info_t), &pdev->dev);
11
12 platform_set_drvdata(pdev, fbinfo);
13
14 info = fbinfo->par; //私有数据是一个结构体s3cfb_info_t
15 info->dev = &pdev->dev;
16
17 //获取LCD的io端口,并映射
18 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
19 size = (res->end - res->start) + 1;
20 info->mem = request_mem_region(res->start, size, pdev->name);
21 info->io = ioremap(res->start, size);
22
23 s3cfb_pre_init(); //2.使能中断寄存器,s3cfb_fimd的第一次初始化
24 s3cfb_set_backlight_power(1); //设置backlight_power = 1;
25 s3cfb_set_lcd_power(1); //设置lcd_power = 1;
26 s3cfb_set_backlight_level(S3CFB_DEFAULT_BACKLIGHT_LEVEL); //设置backlight_level = 2;
27
28 //获取时钟,并使能
29 info->clk = clk_get(NULL, "lcd"); //133.000Mhz,使用的是HCLK
30 clk_enable(info->clk);
31
32 s3cfb_fimd.vsync_info.count = 0;
33 init_waitqueue_head(&s3cfb_fimd.vsync_info.wait_queue);
34
35 //申请中断
36 res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
37 ret = request_irq(res->start, s3cfb_irq, 0, "s3c-lcd", pdev);
38 msleep(5);
39 //对4个framebuffer分别初始化
40 for (index = 0; index < S3CFB_NUM; index++) {
41 s3cfb_info[index].mem = info->mem;
42 s3cfb_info[index].io = info->io;
43 s3cfb_info[index].clk = info->clk;
44
45 s3cfb_init_fbinfo(&s3cfb_info[index], driver_name, index); //3.初始化fbinfo
46 ret = s3cfb_map_video_memory(&s3cfb_info[index]); //4.分配dma内存
47
48 ret = s3cfb_init_registers(&s3cfb_info[index]); //5.写寄存器
49 ret = s3cfb_check_var(&s3cfb_info[index].fb.var, &s3cfb_info[index].fb); //6.设置var范围
50
51 if (index < 2){
52 if (fb_alloc_cmap(&s3cfb_info[index].fb.cmap, 256, 0) < 0) //7.申请color map
53 goto dealloc_fb;
54 } else {
55 if (fb_alloc_cmap(&s3cfb_info[index].fb.cmap, 16, 0) < 0)
56 goto dealloc_fb;
57 }
58
59 ret = register_framebuffer(&s3cfb_info[index].fb); //8.注册framebuffer
60 }
61
62 ret = device_create_file(&(pdev->dev), &dev_attr_backlight_power);
63 ret = device_create_file(&(pdev->dev), &dev_attr_backlight_level);
64 ret = device_create_file(&(pdev->dev), &dev_attr_lcd_power);
65 return 0;
66 }
1.分配内存
分配fb_info+size大小的内存,并使par指向私有数据size
1 struct fb_info *framebuffer_alloc(size_t size, struct device *dev)
2 {
3 fb_info_size += PADDING; //加上PADDING是让私有数据4字节对齐
4 char *p = kzalloc(fb_info_size + size, GFP_KERNEL);
5
6 struct fb_info * info = (struct fb_info *) p;
7 info->par = p + fb_info_size; //par指向私有数据
8 info->device = dev;
9 return info; //返回申请内存的首指针
10 }
2. 初始化视频中断控制寄存器0
在drivers/video/samsun/s3cfb_fimd4x.c中
1 void s3cfb_pre_init(void)
2 {
3 //Video Frame Interrupt 0 at start of VSYNC,并使能
4 s3cfb_fimd.vidintcon0 &= ~S3C_VIDINTCON0_FRAMESEL0_MASK;
5 s3cfb_fimd.vidintcon0 |= S3C_VIDINTCON0_FRAMESEL0_VSYNC;
6 s3cfb_fimd.vidintcon0 |= S3C_VIDINTCON0_INTFRMEN_ENABLE;
7 //0x9021=1001 0000 0010 0001
8 //打开video 中断,关闭fifo 中断
9 //打开 video frame 中断, Video Frame Interrupt 0 at start of VSYNC
10 writel(s3cfb_fimd.vidintcon0, S3C_VIDINTCON0);
11 }
在driver/vidoe/samsun/s3cfb.c中
1 static void s3cfb_set_lcd_power(int to)
2 {
3 s3cfb_fimd.lcd_power = to;
4 }
5
6 static void s3cfb_set_backlight_power(int to)
7 {
8 s3cfb_fimd.backlight_power = to;
9 }
10
11 static void s3cfb_set_backlight_level(int to)
12 {
13 s3cfb_fimd.backlight_level = to;
14 }
3. 初始化s3cfb_info_t结构体
在driver/vidoe/samsun/s3cfb.c中
1 static void s3cfb_init_fbinfo(s3cfb_info_t *finfo, char *drv_name, int index)
2 {
3 int i = 0;
4 if (index == 0)
5 {
6 if(lcdsize == 1)
7 s3cfb_init_hw_43(); //3.1 s3cfb_fimd及gpio的初始化
8 }
9 strcpy(finfo->fb.fix.id, drv_name);
10 //下面一大段就是要将初始化好后的s3cfb_fimd赋给finfo,类似于结构体转化
11 finfo->win_id = index;
12 finfo->fb.fix.type = FB_TYPE_PACKED_PIXELS;
13 finfo->fb.fix.type_aux = 0;
14 finfo->fb.fix.xpanstep = 0;
15 finfo->fb.fix.ypanstep = 1;
16 finfo->fb.fix.ywrapstep = 0;
17 finfo->fb.fix.accel = FB_ACCEL_NONE;
18
19 finfo->fb.fbops = &s3cfb_ops; //fb操作函数
20 finfo->fb.flags = FBINFO_FLAG_DEFAULT;
21
22 finfo->fb.pseudo_palette = &finfo->pseudo_pal;
23
24 finfo->fb.var.nonstd = 0;
25 finfo->fb.var.activate = FB_ACTIVATE_NOW;
26 finfo->fb.var.accel_flags = 0;
27 finfo->fb.var.vmode = FB_VMODE_NONINTERLACED;
28
29 finfo->fb.var.xoffset = s3cfb_fimd.xoffset; //xoffset=0
30 finfo->fb.var.yoffset = s3cfb_fimd.yoffset; //yoffset=0
31
32 if (index == 0) {
33 finfo->fb.var.height = s3cfb_fimd.height; //height=272
34 finfo->fb.var.width = s3cfb_fimd.width; //width=480
35
36 finfo->fb.var.xres = s3cfb_fimd.xres; //xres=480
37 finfo->fb.var.yres = s3cfb_fimd.yres; //yres=272
38
39 finfo->fb.var.xres_virtual = s3cfb_fimd.xres_virtual; //xres_virtual=480
40 finfo->fb.var.yres_virtual = s3cfb_fimd.yres_virtual; //yres_virtual=544
41 } else {
42 finfo->fb.var.height = s3cfb_fimd.osd_height; //osd_height=272
43 finfo->fb.var.width = s3cfb_fimd.osd_width; //osd_height=480
44
45 finfo->fb.var.xres = s3cfb_fimd.osd_xres; //osd_xres=480
46 finfo->fb.var.yres = s3cfb_fimd.osd_yres; //osd_yres=272
47
48 finfo->fb.var.xres_virtual = s3cfb_fimd.osd_xres_virtual; //osd_xres_virtual=480
49 finfo->fb.var.yres_virtual = s3cfb_fimd.osd_yres_virtual; //osd_yres_virtaul=272
50 }
51
52 finfo->fb.var.bits_per_pixel = s3cfb_fimd.bpp; //16
53 finfo->fb.var.pixclock = s3cfb_fimd.pixclock; //9009000
54 finfo->fb.var.hsync_len = s3cfb_fimd.hsync_len; //41
55 finfo->fb.var.left_margin = s3cfb_fimd.left_margin; //2
56 finfo->fb.var.right_margin = s3cfb_fimd.right_margin; //2
57 finfo->fb.var.vsync_len = s3cfb_fimd.vsync_len; //10
58 finfo->fb.var.upper_margin = s3cfb_fimd.upper_margin; //2
59 finfo->fb.var.lower_margin = s3cfb_fimd.lower_margin; //2
60 finfo->fb.var.sync = s3cfb_fimd.sync; //0
61 finfo->fb.var.grayscale = s3cfb_fimd.cmap_grayscale; //0
62 //480*544*2=522240
63 finfo->fb.fix.smem_len = finfo->fb.var.xres_virtual * finfo->fb.var.yres_virtual * s3cfb_fimd.bytes_per_pixel;
64 finfo->fb.fix.line_length = finfo->fb.var.width * s3cfb_fimd.bytes_per_pixel; //480*2=960
65
66 for (i = 0; i < 256; i++)
67 finfo->palette_buffer[i] = S3CFB_PALETTE_BUFF_CLEAR; //(0x80000000)
68 }
3.1 初始化s3cfb_fimd及gpio的初始化
在drviers/video/samsung/s3cfb_WXCAT43.c中
1 void s3cfb_init_hw_43(void)
2 {
3 s3cfb_set_fimd_info(); //3.1.1 s3cfb_fimd的第二次初始化
4 s3cfb_set_gpio(); //3.1.2 gpio口初始化
5 }
3.1.1 s3cfb_fimd结构体的第二次初始化
s3cfb_probe
--> s3cfb_init_fbinfo
--> s3cfb_init_hw_43
--> s3cfb_set_fimd_info
1 static void s3cfb_set_fimd_info(void)
2 {
3 // bit[7]= 0: RGB type LCD driver gets the video data at VCLK falling edge,下降沿获取数据
4 // bit[6]= 1: HSYNC 极性反转
5 // bit[5]= 1: VSYNC 极性反转
6 // bit[4]= 0: VDEN 极性不变
7 s3cfb_fimd.vidcon1 = S3C_VIDCON1_IHSYNC_INVERT | S3C_VIDCON1_IVSYNC_INVERT | S3C_VIDCON1_IVDEN_NORMAL; //0x60
8 //VBPDE[31-24]=0x0
9 //VBPD[23-16]=0x01
10 //VFPD[15-8]=0x01
11 //VSPW[7-0]=0x09
12 s3cfb_fimd.vidtcon0 = S3C_VIDTCON0_VBPD(S3CFB_VBP - 1) | S3C_VIDTCON0_VFPD(S3CFB_VFP - 1) | S3C_VIDTCON0_VSPW(S3CFB_VSW - 1); //0x10109
13 //HBPDE[31-24]=0x0
14 //HBPD[23-16]=0x01
15 //HFPD[15-8]=0x01
16 //HSPW[7-0]=0x28=40
17 s3cfb_fimd.vidtcon1 = S3C_VIDTCON1_HBPD(S3CFB_HBP - 1) | S3C_VIDTCON1_HFPD(S3CFB_HFP - 1) | S3C_VIDTCON1_HSPW(S3CFB_HSW - 1); //0x10128
18 //LINEVAL[21-11]=(Vertical display size)–1=10F=271
19 //HOZVAL[10-0] = (Horizontal display size)-1=1DF=479
20 s3cfb_fimd.vidtcon2 = S3C_VIDTCON2_LINEVAL(S3CFB_VRES - 1) | S3C_VIDTCON2_HOZVAL(S3CFB_HRES - 1); //0x879df
21 //OSD_LeftTopX_F[21-11] = 0
22 //OSD_LeftTopY_F[10-0] = 0 window_0左上角的坐标是(0,0)
23 s3cfb_fimd.vidosd0a = S3C_VIDOSDxA_OSD_LTX_F(0) | S3C_VIDOSDxA_OSD_LTY_F(0); //0x0
24 //OSD_RightBotX_F[21-11] = 0x1DF=479
25 //OSD_RightBotY_F[10-0] = 0x10f =271 window_0右下角的坐标是(479,271)
26 s3cfb_fimd.vidosd0b = S3C_VIDOSDxB_OSD_RBX_F(S3CFB_HRES - 1) | S3C_VIDOSDxB_OSD_RBY_F(S3CFB_VRES - 1); //0xef90f
27 //OSD_LeftTopX_F[21-11] = 0
28 //OSD_LeftTopY_F[10-0] = 0 window_1左上角的坐标是(0,0)
29 s3cfb_fimd.vidosd1a = S3C_VIDOSDxA_OSD_LTX_F(0) | S3C_VIDOSDxA_OSD_LTY_F(0); //0x0
30 //OSD_RightBotX_F[21-11] = 0x1DF=479
31 //OSD_RightBotY_F[10-0] = 0x10f =271 window_1右下角的坐标是(479,271)
32 s3cfb_fimd.vidosd1b = S3C_VIDOSDxB_OSD_RBX_F(S3CFB_HRES_OSD - 1) | S3C_VIDOSDxB_OSD_RBY_F(S3CFB_VRES_OSD - 1); //0xef90f
33
34 s3cfb_fimd.width = S3CFB_HRES; //480
35 s3cfb_fimd.height = S3CFB_VRES; //272
36 s3cfb_fimd.xres = S3CFB_HRES; //480
37 s3cfb_fimd.yres = S3CFB_VRES; //272
38
39 //定义了(CONFIG_FB_S3C_EXT_VIRTUAL_SCREEN)
40 s3cfb_fimd.xres_virtual = S3CFB_HRES_VIRTUAL; //如果定义了Virtual_screen则为480*544
41 s3cfb_fimd.yres_virtual = S3CFB_VRES_VIRTUAL; //如果没有定义Virtual_screen则为480*272
42
43 s3cfb_fimd.osd_width = S3CFB_HRES_OSD; //480
44 s3cfb_fimd.osd_height = S3CFB_VRES_OSD; //272
45 s3cfb_fimd.osd_xres = S3CFB_HRES_OSD; //480
46 s3cfb_fimd.osd_yres = S3CFB_VRES_OSD; //272
47
48 s3cfb_fimd.osd_xres_virtual = S3CFB_HRES_OSD; //480
49 s3cfb_fimd.osd_yres_virtual = S3CFB_VRES_OSD; //272
50
51 s3cfb_fimd.pixclock = S3CFB_PIXEL_CLOCK; //9009000
52
53 s3cfb_fimd.hsync_len = S3CFB_HSW; //41
54 s3cfb_fimd.vsync_len = S3CFB_VSW; //10
55 s3cfb_fimd.left_margin = S3CFB_HFP; //2
56 s3cfb_fimd.upper_margin = S3CFB_VFP; //2
57 s3cfb_fimd.right_margin = S3CFB_HBP; //2
58 s3cfb_fimd.lower_margin = S3CFB_VBP; //2
59 }
小总结一下:
全局变量s3cfb_fimd_info_t s3cfb_fimd
首先定义在drivers/video/samsun/s3cfb_fimd4x.c中
第1次初始化
s3cfb_probe
--> s3cfb_pre_init();
打开video 中断,关闭fifo 中断
打开 video frame 中断, Video Frame Interrupt 0 at start of VSYNC
第2次初始化
s3cfb_probe
--> s3cfb_init_fbinfo
--> s3cfb_init_hw_43
--> s3cfb_set_fimd_info
3.1.2 gpio口初始化
在
1 int s3cfb_set_gpio(void)
2 {
3 //将HCLK clock gating control寄存器0x7E00_F030的bit3设为1,即使能LCD的时钟
4 val = readl(S3C_HCLK_GATE);
5 val |= S3C_CLKCON_HCLK_LCD;
6 writel(val, S3C_HCLK_GATE);
7 //设置Special PortControl Register寄存器0x7F0081A0的bit[0-1]设为01,即RGB I/F style
8 val = readl(S3C64XX_SPCON);
9 val &= ~0x3;
10 val |= (1 << 0);
11 writel(val, S3C64XX_SPCON);
12
13 //VD[0-15]连在了GPI[0-15]上,所以要把GPI口配成LCD
14 for (i = 0; i < 16; i++)
15 s3c_gpio_cfgpin(S3C64XX_GPI(i), S3C_GPIO_SFN(2));
16
17 //VD[16-23]连在了GPJ[0-7]上,所以要把GPJ口配成LCD
18 //HSYNC-->GPJ8, VSYNC-->GPJ9, VDEN-->GPJ10, VCLK-->GPJ11
19 for (i = 0; i < 12; i++)
20 s3c_gpio_cfgpin(S3C64XX_GPJ(i), S3C_GPIO_SFN(2));
21
22 //ok6410跟GPE0好像没有什么关系,这儿可以去掉
23 if (gpio_is_valid(S3C64XX_GPE(0))) {
24 err = gpio_request(S3C64XX_GPE(0), "GPE");
25 gpio_direction_output(S3C64XX_GPE(0), 1);
26 }
27 gpio_set_value(S3C64XX_GPE(0), 1);
28 gpio_free(S3C64XX_GPE(0));
29 gpio_free(S3C64XX_GPF(14));
30 return 0;
31 }
4. 分配DMA内存
第1个window,双缓冲 0x7f8000=320*240*3*2
FB1: map_video_memory: dma=5f180000 cpu=ff600000 size=0007f800
Window[0] - FB2: map_video_memory: dma=5f1bfc00 cpu=ff63fc00 size=0003fc00
第2个window,双缓冲
FB1: map_video_memory: dma=5f200000 cpu=ff700000 size=0007f800
Window[1] - FB2: map_video_memory: dma=5f23fc00 cpu=ff73fc00 size=0003fc00
在drivers/vidoe/samsun/s3cfb.c中
1 static int __init s3cfb_map_video_memory(s3cfb_info_t *fbi)
2 {
3 fbi->map_size_f1 = PAGE_ALIGN(fbi->fb.fix.smem_len); //480*272*n对齐到4K
4 //index=0时在DMA空间分配480*272*4=0x7f800=对齐后0x80000大小的DMA内存
5 //index=1,2,3时在DMA空间分配480*272*2=0x3fc00=对齐后0x40000大小的DMA内存
6 fbi->map_cpu_f1 = dma_alloc_writecombine(fbi->dev, fbi->map_size_f1, &fbi->map_dma_f1, GFP_KERNEL); //分配dma内存
7 fbi->map_size_f1 = fbi->fb.fix.smem_len; //480*272*n原始大小,不对齐到4K
8
9 if (fbi->map_cpu_f1) { //map_cpu_f1是将dma映射到虚拟内存空间的地址
10 memset(fbi->map_cpu_f1, 0xf0, fbi->map_size_f1); //初始化成0xf0?这儿为什么不是0?
11 fbi->screen_dma_f1 = fbi->map_dma_f1;
12 fbi->fb.screen_base = fbi->map_cpu_f1;
13 fbi->fb.fix.smem_start = fbi->screen_dma_f1;
14 }
15 //下面的指针指向第二个 buffer
16 #if defined(CONFIG_FB_S3C_EXT_DOUBLE_BUFFERING)
17 if (fbi->win_id<2 && fbi->map_cpu_f1) {
18 fbi->map_size_f2 = (fbi->fb.fix.smem_len / 2);
19 fbi->map_cpu_f2 = fbi->map_cpu_f1 + fbi->map_size_f2;
20 fbi->map_dma_f2 = fbi->map_dma_f1 + fbi->map_size_f2;
21 fbi->screen_dma_f2 = fbi->map_dma_f2;
22 }
23 #endif
24 return 0;
25 }
注: void *dma_alloc_writecombine(struct device *, size_t, dma_addr_t *, gfp_t);
arg1是设备名
arg2是分配dma buffer的长度
arg3是分配dma的物理地址,利用指针改写
arg4是标志GFP_KERNEL
ret 返回分配dma的虚拟地址
ret 与 arg3都指向同一块内存,只不过argc3是物理地址,ret是虚拟地址.
dma_alloc_coherent: 禁止页表项中的C(cacheable)以及B(bufferable)域
dma_alloc_writecombine只是禁止C(Cacheable)域.即不使用cache
5. 写寄存器
在driver/video/samsun中
1 int s3cfb_init_registers(s3cfb_info_t *fbi)
2 {
3 struct clk *lcd_clock;
4 struct fb_var_screeninfo *var = &fbi->fb.var;
5 unsigned long flags = 0, page_width = 0, offset = 0;
6 unsigned long video_phy_temp_f1 = fbi->screen_dma_f1;
7 unsigned long video_phy_temp_f2 = fbi->screen_dma_f2;
8 int win_num = fbi->win_id;
9
10 local_irq_save(flags); //关中断,并保存
11
12 page_width = var->xres * s3cfb_fimd.bytes_per_pixel; //page_width=960
13 offset = (var->xres_virtual - var->xres) * s3cfb_fimd.bytes_per_pixel; //offset=0
14 if (win_num == 0) {
15 s3cfb_fimd.vidcon0 = s3cfb_fimd.vidcon0 & ~(S3C_VIDCON0_ENVID_ENABLE | S3C_VIDCON0_ENVID_F_ENABLE);
16 writel(s3cfb_fimd.vidcon0, S3C_VIDCON0); //设置lcd的clk分频-->Divided by CLKVAL_F
17
18 lcd_clock = clk_get(NULL, "lcd");
19 s3cfb_fimd.vidcon0 |= S3C_VIDCON0_CLKVAL_F((int) ((clk_get_rate(lcd_clock) / s3cfb_fimd.pixclock) - 1));
20 //lcd_clock->rate=13M, s3cfb_fimd.pixclock=9M, s3cfb_fimd.vidcon0[13-6]=13
21 #if defined(CONFIG_FB_S3C_EXT_VIRTUAL_SCREEN)
22 offset = 0;
23 s3cfb_fimd.vidw00add0b0 = video_phy_temp_f1;
24 s3cfb_fimd.vidw00add0b1 = video_phy_temp_f2;
25 s3cfb_fimd.vidw00add1b0 = S3C_VIDWxxADD1_VBASEL_F((unsigned long) video_phy_temp_f1 + (page_width + offset) * (var->yres));
26 s3cfb_fimd.vidw00add1b1 = S3C_VIDWxxADD1_VBASEL_F((unsigned long) video_phy_temp_f2 + (page_width + offset) * (var->yres));
27 #endif
28 }
29
30 writel(video_phy_temp_f1, S3C_VIDW00ADD0B0 + (0x08 * win_num));
31 writel(S3C_VIDWxxADD1_VBASEL_F((unsigned long) video_phy_temp_f1 + (page_width + offset) * (var->yres)), S3C_VIDW00ADD1B0 + (0x08 * win_num));
32 writel(S3C_VIDWxxADD2_OFFSIZE_F(offset) | (S3C_VIDWxxADD2_PAGEWIDTH_F(page_width)), S3C_VIDW00ADD2 + (0x04 * win_num));
33
34 if (win_num < 2) {
35 writel(video_phy_temp_f2, S3C_VIDW00ADD0B1 + (0x08 * win_num));
36 writel(S3C_VIDWxxADD1_VBASEL_F((unsigned long) video_phy_temp_f2 + (page_width + offset) * (var->yres)), S3C_VIDW00ADD1B1 + (0x08 * win_num));
37 }
38
39 switch (win_num) {
40 case 0:
41 //wincon0=0x110014=0001 0001 0000 0000 0001 0100
42 //bit[0]=video output disable --> 导致bit[22]=0
43 //bit[5-2]=0101=16BPP (R5 G6 B5)
44 //bit[10-9]=00 = DMA's Burst Max len 16word
45 //bit[13] = 0 = input color space RGB
46 //bit[16] = 1 = half wrod swap enabel
47 //bit[20] = 1 = select buf 1
48 writel(s3cfb_fimd.wincon0, S3C_WINCON0);
49
50 //vidcon0=0x350=0011 0101 0000
51 //bit[3-2]=00 = VideoClock source = HCLK
52 //bit[4]=1=video clock Divided by CLKVAL_F
53 //bit[13-6]=00 1101 = 13 HCLK/CLKVAL_F=133/13=10.230769231M
54 writel(s3cfb_fimd.vidcon0, S3C_VIDCON0);
55
56 //vidcon1=0x60 = 0110 0000
57 //bit[4]= VDEN polarity noraml
58 //bit[5]=VSYNC polarity inverted
59 //bit[6]=HSYNC polarity inverted
60 //bit[7]=gets the video data at vclk falling
61 writel(s3cfb_fimd.vidcon1, S3C_VIDCON1);
62
63 //vidtcon0=0x10109
64 //VBPDE[31-24]= 0x0
65 //VBPD[23-16]= 0x01
66 //VFPD[15-8]= 0x01
67 //VSPW[7-0]= 0x09
68 writel(s3cfb_fimd.vidtcon0, S3C_VIDTCON0);
69
70 //vidtcon1=0x10128
71 //VFPDE[31-24]=0x0
72 //HBPD[23-16]=0x01
73 //HFPD[15-8]=0x01
74 //HSPW[7-0]= 0x28=40
75 writel(s3cfb_fimd.vidtcon1, S3C_VIDTCON1);
76
77 //vidtcon2=0x879df
78 //LINEVAL[21-11]=(Vertical display size)–1=10F=271
79 //HOZVAL[10-0] = (Horizontal display size)-1=1DF=479
80 writel(s3cfb_fimd.vidtcon2, S3C_VIDTCON2);
81
82 //dithmode=0x0
83 //禁用dither
84 writel(s3cfb_fimd.dithmode, S3C_DITHMODE);
85
86 //vidintcon0=0x9021=0x1001 0000 0010 0001
87 //bit[0]=Video Interrupt Enable
88 //bit[1]=FIFO disable
89 //bit[4-2]=FIFO int level =25
90 //bit[11-5]=FIFO int -->win 0 control enable
91 //bit[12]=video Frame interrupt enable
92 //bit[14-13]=video frame int 1 start of None
93 //bit[16-15]=video frame int 0 start of VSYNC
94 writel(s3cfb_fimd.vidintcon0, S3C_VIDINTCON0);
95
96 //vidintcon1=0x0
97 //没看出什么用
98 writel(s3cfb_fimd.vidintcon1, S3C_VIDINTCON1);
99
100 //vidosd0a=0x0
101 //window_0左上角坐标(0,0)
102 writel(s3cfb_fimd.vidosd0a, S3C_VIDOSD0A);
103
104 //vidosd0b=0xef90f
105 //window_0右下角的坐标是(479,271)
106 writel(s3cfb_fimd.vidosd0b, S3C_VIDOSD0B);
107
108 //vidosd0c=0x0
109 //bit[23-0]=Window Size = 竟然为0?
110 writel(s3cfb_fimd.vidosd0c, S3C_VIDOSD0C);
111
112 //wpalcon=0x6
113 //
114 //
115 //
116 writel(s3cfb_fimd.wpalcon, S3C_WPALCON);
117
118 //
119 s3cfb_onoff_win(fbi, ON);
120 break;
121 case 1-4:
122 类推,省略.
123 break;
124 }
125
126 local_irq_restore(flags); //开中断,并恢复,于上面的local_irq_save正好相反
127
128 return 0;
129 }
6. 规定范围
1 static int s3cfb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
2 {
3 s3cfb_info_t *fbi = (s3cfb_info_t *) info;
4 switch (var->bits_per_pixel) {
5 case 16:
6 var->red = s3cfb_rgb_16.red; //{.offset = 11, .length = 5,},
7 var->green = s3cfb_rgb_16.green; //{.offset = 5, .length = 6,},
8 var->blue = s3cfb_rgb_16.blue; //{.offset = 0, .length = 5,},
9 var->transp = s3cfb_rgb_16.transp; //{.offset = 0, .length = 0,},
10 s3cfb_fimd.bytes_per_pixel = 2; //每个像素2个字节
11 break;
12 }
13 //对窗口0进行特殊处理
14 if( (fbi->win_id == 0) && (var->bits_per_pixel == 28) )
15 var->transp.length = 0;
16
17 return 0;
18 }
7. 分配并初始化color map
fb_alloc_cmap(&s3cfb_info[index].fb.cmap, 256, 0);
1 int fb_alloc_cmap(struct fb_cmap *cmap, int len, int transp)
2 {
3 return fb_alloc_cmap_gfp(cmap, len, transp, GFP_ATOMIC);
4 }
在driver/video/fbcmap.c中
1 int fb_alloc_cmap_gfp(struct fb_cmap *cmap, int len, int transp, gfp_t flags)
2 {
3 int size = len * sizeof(u16);
4
5 if (cmap->len != len) {
6 fb_dealloc_cmap(cmap); //把以前申请的rgb内存kfree掉
7 cmap->red = kmalloc(size, flags); //重新分配内存,GFP_ATOMIC
8 cmap->green = kmalloc(size, flags); //重新分配内存,GFP_ATOMIC
9 cmap->blue = kmalloc(size, flags); //重新分配内存,GFP_ATOMIC
10 if (transp) {
11 cmap->transp = kmalloc(size, flags);
12 } else {
13 cmap->transp = NULL; //transp设为NULL
14 }
15 }
16 cmap->start = 0;
17 cmap->len = len;
18 ret = fb_copy_cmap(fb_default_cmap(len), cmap); //把default的cmap复制到新分配的cmap中
19 return 0;
20 }
上层执行fb_set_par
--> s3cfb_set_par
1 static int s3cfb_set_par(struct fb_info *info)
2 {
3 //var->bits_per_pixel=16, s3cfb_fimd.bytes_per_pixel=2
4 fbi->fb.fix.visual = FB_VISUAL_TRUECOLOR;
5 fbi->fb.fix.line_length = var->width * s3cfb_fimd.bytes_per_pixel;
6 s3cfb_activate_var(fbi, var);
7 return 0;
8 }
上层执行fb_set_par
--> s3cfb_set_par
--> s3cfb_activate_var
根据像素位数设置寄存器.
1 void s3cfb_activate_var(s3cfb_info_t *fbi, struct fb_var_screeninfo *var)
2 {
3 switch (var->bits_per_pixel) {
4 case 16:
5 s3cfb_fimd.wincon0 = S3C_WINCONx_HAWSWP_ENABLE | S3C_WINCONx_BURSTLEN_16WORD | S3C_WINCONx_BPPMODE_F_16BPP_565;
6 s3cfb_fimd.wincon1 = S3C_WINCONx_HAWSWP_ENABLE | S3C_WINCONx_BURSTLEN_16WORD | S3C_WINCONx_BPPMODE_F_16BPP_565 | S3C_WINCONx_BLD_PIX_PLANE | S3C_WINCONx_ALPHA_SEL_1;
7 s3cfb_fimd.wincon2 = S3C_WINCONx_HAWSWP_ENABLE | S3C_WINCONx_BURSTLEN_16WORD | S3C_WINCONx_BPPMODE_F_16BPP_565 | S3C_WINCONx_BLD_PIX_PLANE | S3C_WINCONx_ALPHA_SEL_1;
8 s3cfb_fimd.wincon3 = S3C_WINCONx_HAWSWP_ENABLE | S3C_WINCONx_BURSTLEN_16WORD | S3C_WINCONx_BPPMODE_F_16BPP_565 | S3C_WINCONx_BLD_PIX_PLANE | S3C_WINCONx_ALPHA_SEL_1;
9 s3cfb_fimd.wincon4 = S3C_WINCONx_HAWSWP_ENABLE | S3C_WINCONx_BURSTLEN_16WORD | S3C_WINCONx_BPPMODE_F_16BPP_565 | S3C_WINCONx_BLD_PIX_PLANE | S3C_WINCONx_ALPHA_SEL_1;
10 s3cfb_fimd.bpp = S3CFB_PIXEL_BPP_16;
11 s3cfb_fimd.bytes_per_pixel = 2;
12 break;
13 }
14 //配置为窗口0,1,2,3,4为rgb565模式,dma直传,burst mode, BURSTLEN=16Word
15 writel(s3cfb_fimd.wincon0, S3C_WINCON0); //0x10014
16 writel(s3cfb_fimd.wincon1, S3C_WINCON1); //0x10016
17 writel(s3cfb_fimd.wincon2, S3C_WINCON2); //0x10016
18 writel(s3cfb_fimd.wincon3, S3C_WINCON3); //0x10016
19 writel(s3cfb_fimd.wincon4, S3C_WINCON4); //0x10016
20 writel(s3cfb_fimd.wpalcon, S3C_WPALCON); //0x00006
21 //启动video output
22 writel(s3cfb_fimd.wincon0 | S3C_WINCONx_ENWIN_F_ENABLE, S3C_WINCON0); //0x10014
23 //设置clock并启动video output
24 writel(s3cfb_fimd.vidcon0 | S3C_VIDCON0_ENVID_ENABLE | S3C_VIDCON0_ENVID_F_ENABLE, S3C_VIDCON0); //0x350
25 }
三. 中断及数据传输
3.1 中断过程
1 irqreturn_t s3cfb_irq(int irqno, void *param)
2 {
3 writel(readl(S3C_VIDINTCON1), S3C_VIDINTCON1); //清中断
4
5 s3cfb_fimd.vsync_info.count++;
6 wake_up_interruptible(&s3cfb_fimd.vsync_info.wait_queue); //唤醒工作队列
7 return IRQ_HANDLED;
8 }
这个地方正在等侍工作队列,收到唤醒信号之后,就返回
1 int s3cfb_wait_for_vsync(void)
2 {
3 cnt = s3cfb_fimd.vsync_info.count;
4 wait_event_interruptible_timeout(s3cfb_fimd.vsync_info.wait_queue, cnt != s3cfb_fimd.vsync_info.count, HZ / 10);
5 return cnt;
6 }
1 int s3cfb_ioctl(struct fb_info *info, unsigned int cmd, unsigned long arg)
2 {
3 switch(cmd){
4 case FBIO_WAITFORVSYNC:
5 if (get_user(crt, (unsigned int __user *)arg))
6 return -EFAULT;
7
8 return s3cfb_wait_for_vsync();
9 }
10 }
附录:
1. local_irq_save
s3cfb_probe
--> s3cfb_init_registers
--> local_irq_save
2. 关于DMA
s3cfb_probe
--> s3cfb_map_video_memory
--> dma_alloc_writecombine
--> __dma_alloc
转自：http://blog.chinaunix.net/uid-26009923-id-3929286.html
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