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
