1. LCD設備驅動相關的數據結構
- struct fb_info {
- atomic_t count;
- int node;
- int flags;
- struct mutex lock; /* Lock for open/release/ioctl funcs */
- struct mutex mm_lock; /* Lock for fb_mmap and smem_* fields */
- struct fb_var_screeninfo var; /* Current var */ //可變參數
- struct fb_fix_screeninfo fix; /* Current fix */ //固定參數
- struct fb_monspecs monspecs; /* Current Monitor specs */ //顯示器標誌
- struct work_struct queue; /* Framebuffer event queue */
- struct fb_pixmap pixmap; /* Image hardware mapper */ //圖像硬件映射
- struct fb_pixmap sprite; /* Cursor hardware mapper */ //光標硬件映射
- struct fb_cmap cmap; /* Current cmap */ //調色板
- struct list_head modelist; /* mode list */
- struct fb_videomode *mode; /* current mode */ //視頻模式
- #ifdef CONFIG_FB_BACKLIGHT
- /* assigned backlight device */
- /* set before framebuffer registration,
- remove after unregister */
- struct backlight_device *bl_dev;
- /* Backlight level curve */
- struct mutex bl_curve_mutex;
- u8 bl_curve[FB_BACKLIGHT_LEVELS];
- #endif
- #ifdef CONFIG_FB_DEFERRED_IO
- struct delayed_work deferred_work;
- struct fb_deferred_io *fbdefio;
- #endif
- struct fb_ops *fbops; //幀緩衝操作函數集
- struct device *device; /* This is the parent */
- struct device *dev; /* This is this fb device */
- int class_flag; /* private sysfs flags */
- #ifdef CONFIG_FB_TILEBLITTING
- struct fb_tile_ops *tileops; /* Tile Blitting */
- #endif
- char __iomem *screen_base; /* Virtual address */ //虛擬基地址
- unsigned long screen_size; /* Amount of ioremapped VRAM or 0 */ //ioremap的虛擬內存大小
- void *pseudo_palette; /* Fake palette of 16 colors */
- #define FBINFO_STATE_RUNNING 0
- #define FBINFO_STATE_SUSPENDED 1
- u32 state; /* Hardware state i.e suspend */
- void *fbcon_par; /* fbcon use-only private area */
- /* From here on everything is device dependent */
- void *par;
- /* we need the PCI or similar aperture base/size not
- smem_start/size as smem_start may just be an object
- allocated inside the aperture so may not actually overlap */
- struct apertures_struct {
- unsigned int count;
- struct aperture {
- resource_size_t base;
- resource_size_t size;
- } ranges[0];
- } *apertures;
- };
- struct fb_var_screeninfo {
- __u32 xres; /* visible resolution */ //x方向可見解析度
- __u32 yres;
- __u32 xres_virtual; /* virtual resolution */ //x方向虛擬解析度
- __u32 yres_virtual;
- __u32 xoffset; /* offset from virtual to visible */ //可見和不可見部分的偏移
- __u32 yoffset; /* resolution */
- __u32 bits_per_pixel; /* guess what */ //每一個像素的位數
- __u32 grayscale; /* != 0 Graylevels instead of colors */
- struct fb_bitfield red; /* bitfield in fb mem if true color, */
- struct fb_bitfield green; /* else only length is significant */
- struct fb_bitfield blue;
- struct fb_bitfield transp; /* transparency */
- __u32 nonstd; /* != 0 Non standard pixel format */
- __u32 activate; /* see FB_ACTIVATE_* */
- __u32 height; /* height of picture in mm */ //屏幕的高度
- __u32 width; /* width of picture in mm */ //屏幕的寬度
- __u32 accel_flags; /* (OBSOLETE) see fb_info.flags */
- /* Timing: All values in pixclocks, except pixclock (of course) */
- __u32 pixclock; /* pixel clock in ps (pico seconds) */ //像素時鐘
- __u32 left_margin; /* time from sync to picture */ //行切換時間，行同步與開始繪圖之間的延遲
- __u32 right_margin; /* time from picture to sync */ //行切換時間，繪圖結束與行同步之間的延遲
- __u32 upper_margin; /* time from sync to picture */ //幀切換，從同步到開始繪圖之間的延遲
- __u32 lower_margin; //幀切換，從繪圖結束到同步之間的延遲
- __u32 hsync_len; /* length of horizontal sync */ //水平同步的長度
- __u32 vsync_len; /* length of vertical sync */ //垂直同步的長度
- __u32 sync; /* see FB_SYNC_* */
- __u32 vmode; /* see FB_VMODE_* */
- __u32 rotate; /* angle we rotate counter clockwise */
- __u32 reserved[5]; /* Reserved for future compatibility */
- };
- struct fb_fix_screeninfo {
- char id[16]; /* identification string eg "TT Builtin" */
- unsigned long smem_start; /* Start of frame buffer mem */ //fb緩衝區的開始位置
- /* (physical address) */<span style="white-space:pre"> </span>
- __u32 smem_len; /* Length of frame buffer mem */ //fb緩衝區的長度
- __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 */ //1行的字節數
- unsigned long mmio_start; /* Start of Memory Mapped I/O */ //內存映射IO的開始位置
- /* (physical address) */
- __u32 mmio_len; /* Length of Memory Mapped I/O */ //內存映射IO的長度
- __u32 accel; /* Indicate to driver which */
- /* specific chip/card we have */
- __u16 reserved[3]; /* Reserved for future compatibility */
- };
struct fb_info {
atomic_t count;
int node;
int flags;
struct mutex lock; /* Lock for open/release/ioctl funcs */
struct mutex mm_lock; /* Lock for fb_mmap and smem_* fields */
struct fb_var_screeninfo var; /* Current var */ //可變參數
struct fb_fix_screeninfo fix; /* Current fix */ //固定參數
struct fb_monspecs monspecs; /* Current Monitor specs */ //顯示器標誌
struct work_struct queue; /* Framebuffer event queue */
struct fb_pixmap pixmap; /* Image hardware mapper */ //圖像硬件映射
struct fb_pixmap sprite; /* Cursor hardware mapper */ //光標硬件映射
struct fb_cmap cmap; /* Current cmap */ //調色板
struct list_head modelist; /* mode list */
struct fb_videomode *mode; /* current mode */ //視頻模式
#ifdef CONFIG_FB_BACKLIGHT
/* assigned backlight device */
/* set before framebuffer registration,
remove after unregister */
struct backlight_device *bl_dev;
/* Backlight level curve */
struct mutex bl_curve_mutex;
u8 bl_curve[FB_BACKLIGHT_LEVELS];
#endif
#ifdef CONFIG_FB_DEFERRED_IO
struct delayed_work deferred_work;
struct fb_deferred_io *fbdefio;
#endif
struct fb_ops *fbops; //幀緩衝操作函數集
struct device *device; /* This is the parent */
struct device *dev; /* This is this fb device */
int class_flag; /* private sysfs flags */
#ifdef CONFIG_FB_TILEBLITTING
struct fb_tile_ops *tileops; /* Tile Blitting */
#endif
char __iomem *screen_base; /* Virtual address */ //虛擬基地址
unsigned long screen_size; /* Amount of ioremapped VRAM or 0 */ //ioremap的虛擬內存大小
void *pseudo_palette; /* Fake palette of 16 colors */
#define FBINFO_STATE_RUNNING 0
#define FBINFO_STATE_SUSPENDED 1
u32 state; /* Hardware state i.e suspend */
void *fbcon_par; /* fbcon use-only private area */
/* From here on everything is device dependent */
void *par;
/* we need the PCI or similar aperture base/size not
smem_start/size as smem_start may just be an object
allocated inside the aperture so may not actually overlap */
struct apertures_struct {
unsigned int count;
struct aperture {
resource_size_t base;
resource_size_t size;
} ranges[0];
} *apertures;
};
struct fb_var_screeninfo {
__u32 xres; /* visible resolution */ //x方向可見解析度
__u32 yres;
__u32 xres_virtual; /* virtual resolution */ //x方向虛擬解析度
__u32 yres_virtual;
__u32 xoffset; /* offset from virtual to visible */ //可見和不可見部分的偏移
__u32 yoffset; /* resolution */
__u32 bits_per_pixel; /* guess what */ //每一個像素的位數
__u32 grayscale; /* != 0 Graylevels instead of colors */
struct fb_bitfield red; /* bitfield in fb mem if true color, */
struct fb_bitfield green; /* else only length is significant */
struct fb_bitfield blue;
struct fb_bitfield transp; /* transparency */
__u32 nonstd; /* != 0 Non standard pixel format */
__u32 activate; /* see FB_ACTIVATE_* */
__u32 height; /* height of picture in mm */ //屏幕的高度
__u32 width; /* width of picture in mm */ //屏幕的寬度
__u32 accel_flags; /* (OBSOLETE) see fb_info.flags */
/* Timing: All values in pixclocks, except pixclock (of course) */
__u32 pixclock; /* pixel clock in ps (pico seconds) */ //像素時鐘
__u32 left_margin; /* time from sync to picture */ //行切換時間，行同步與開始繪圖之間的延遲
__u32 right_margin; /* time from picture to sync */ //行切換時間，繪圖結束與行同步之間的延遲
__u32 upper_margin; /* time from sync to picture */ //幀切換，從同步到開始繪圖之間的延遲
__u32 lower_margin; //幀切換，從繪圖結束到同步之間的延遲
__u32 hsync_len; /* length of horizontal sync */ //水平同步的長度
__u32 vsync_len; /* length of vertical sync */ //垂直同步的長度
__u32 sync; /* see FB_SYNC_* */
__u32 vmode; /* see FB_VMODE_* */
__u32 rotate; /* angle we rotate counter clockwise */
__u32 reserved[5]; /* Reserved for future compatibility */
};
struct fb_fix_screeninfo {
char id[16]; /* identification string eg "TT Builtin" */
unsigned long smem_start; /* Start of frame buffer mem */ //fb緩衝區的開始位置
/* (physical address) */<span style="white-space:pre"> </span>
__u32 smem_len; /* Length of frame buffer mem */ //fb緩衝區的長度
__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 */ //1行的字節數
unsigned long mmio_start; /* Start of Memory Mapped I/O */ //內存映射IO的開始位置
/* (physical address) */
__u32 mmio_len; /* Length of Memory Mapped I/O */ //內存映射IO的長度
__u32 accel; /* Indicate to driver which */
/* specific chip/card we have */
__u16 reserved[3]; /* Reserved for future compatibility */
};2. s3c2440 lcd控制器的結構
我們根據數據手冊來描述一下這個集成在S3C2440內部的LCD控制器
LCD控制器由REGBANK、LCDCDMA、TIMEGEN、VIDPRCS寄存器組成；
REGBANK由17個可編程的寄存器組和一塊256*16的調色板內存組成，它們用來配置LCD控制器的；
LCDCDMA是一個專用的DMA，它能自動地把在偵內存中的視頻數據傳送到LCD驅動器，通過使用這個DMA通道，視頻數據在不需要CPU的干預的情況下顯示在LCD屏上；
VIDPRCS接收來自LCDCDMA的數據，將數據轉換爲合適的數據格式，比如說4/8位單掃，4位雙掃顯示模式，然後通過數據端口VD[23:0]傳送視頻數據到LCD驅動器；
TIMEGEN由可編程的邏輯組成，他生成LCD驅動器需要的控制信號，比如VSYNC、HSYNC、VCLK和LEND等等，而這些控制信號又與REGBANK寄存器組中的LCDCON1/2/3/4/5的配置密切相關，通過不同的配置，TIMEGEN就能產生這些信號的不同形態，從而支持不同的LCD驅動器(即不同的STN/TFT屏)。
常見的TFT屏工作時序分析：
VSYNC：垂直同步信號
HSYNC：水平同步信號
VCLK：像素時鐘信號
VD:像素數據輸出端口
VDEN：數據使能信號
LEND：行結束信號
VBPD(vertical back porch)：表示在一幀圖像開始時，垂直同步信號以後的無效的行數，對應驅動中的upper_margin；
VFBD(vertical front porch)：表示在一幀圖像結束後，垂直同步信號以前的無效的行數，對應驅動中的lower_margin；
VSPW(vertical sync pulse width)：表示垂直同步脈衝的寬度，用行數計算，對應驅動中的vsync_len；
HBPD(horizontal back porch)：表示從水平同步信號開始到一行的有效數據開始之間的VCLK的個數，對應驅動中的left_margin；
HFPD(horizontal front porth)：表示一行的有效數據結束到下一個水平同步信號開始之間的VCLK的個數，對應驅動中的right_margin；
HSPW(horizontal sync pulse width)：表示水平同步信號的寬度，用VCLK計算，對應驅動中的hsync_len；
3. 幀緩衝設備的註冊
首先在arch/arm/mach-xx/目錄中定義一些信息
（1）LCD控制器的IO端口開始地址，結束地址，LCD中斷
（2）LCD硬件參數，如LCD的屏幕尺寸，屏幕類型，像素時鐘，水平可見的像素，垂直可見的像素，色位模式，以及上面介紹的6個參數。有的板子可以支持很多個尺寸的屏幕，所以要建立一個數組，default賦值相應的index。
（3）LCD引腳相關的配置，哪些配置成LEND、VCLK、HSYNC、VSYNC、VDEN。
第（1）行的信息保存在platform_device結構的resource成員。
第（2）行和第（3）行的信息保存在platform_device結構的device成員的void *platform_data指針中，在平臺初始化時賦值。
接下來看下probe的過程：
- static int __devinit s3c24xxfb_probe(struct platform_device *pdev,
- enum s3c_drv_type drv_type)
- {
- struct s3c2410fb_info *info; //封裝了fb_info信息的結構
- struct s3c2410fb_display *display; //指向定義的lcd信息
- struct fb_info *fbinfo;
- struct s3c2410fb_mach_info *mach_info; //指向平臺數據
- struct resource *res;
- int ret;
- int irq;
- int i;
- int size;
- u32 lcdcon1;
- mach_info = pdev->dev.platform_data;
- if (mach_info == NULL) {
- dev_err(&pdev->dev,
- "no platform data for lcd, cannot attach\n");
- return -EINVAL;
- }
- if (mach_info->default_display >= mach_info->num_displays) {
- dev_err(&pdev->dev, "default is %d but only %d displays\n",
- mach_info->default_display, mach_info->num_displays);
- return -EINVAL;
- }
- display = mach_info->displays + mach_info->default_display; //指向你定義的lcd信息
- irq = platform_get_irq(pdev, 0);
- if (irq < 0) {
- dev_err(&pdev->dev, "no irq for device\n");
- return -ENOENT;
- }
- fbinfo = framebuffer_alloc(sizeof(struct s3c2410fb_info), &pdev->dev); //分配s3c2410fb_info
- if (!fbinfo)
- return -ENOMEM;
- platform_set_drvdata(pdev, fbinfo);
- info = fbinfo->par;
- info->dev = &pdev->dev;
- info->drv_type = drv_type;
- res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
- if (res == NULL) {
- dev_err(&pdev->dev, "failed to get memory registers\n");
- ret = -ENXIO;
- goto dealloc_fb;
- }
- size = resource_size(res);
- info->mem = request_mem_region(res->start, size, pdev->name);
- if (info->mem == NULL) {
- dev_err(&pdev->dev, "failed to get memory region\n");
- ret = -ENOENT;
- goto dealloc_fb;
- }
- info->io = ioremap(res->start, size);
- if (info->io == NULL) {
- dev_err(&pdev->dev, "ioremap() of registers failed\n");
- ret = -ENXIO;
- goto release_mem;
- }
- info->irq_base = info->io + ((drv_type == DRV_S3C2412) ? S3C2412_LCDINTBASE : S3C2410_LCDINTBASE);
- dprintk("devinit\n");
- strcpy(fbinfo->fix.id, driver_name);
- /* Stop the video */ //關閉顯示器
- lcdcon1 = readl(info->io + S3C2410_LCDCON1);
- writel(lcdcon1 & ~S3C2410_LCDCON1_ENVID, info->io + S3C2410_LCDCON1);
- fbinfo->fix.type = FB_TYPE_PACKED_PIXELS;
- fbinfo->fix.type_aux = 0;
- fbinfo->fix.xpanstep = 0;
- fbinfo->fix.ypanstep = 0;
- fbinfo->fix.ywrapstep = 0;
- fbinfo->fix.accel = FB_ACCEL_NONE;
- fbinfo->var.nonstd = 0;
- fbinfo->var.activate = FB_ACTIVATE_NOW;
- fbinfo->var.accel_flags = 0;
- fbinfo->var.vmode = FB_VMODE_NONINTERLACED;
- fbinfo->fbops = &s3c2410fb_ops; //賦值fb操作函數集
- fbinfo->flags = FBINFO_FLAG_DEFAULT;
- fbinfo->pseudo_palette = &info->pseudo_pal;
- for (i = 0; i < 256; i++)
- info->palette_buffer[i] = PALETTE_BUFF_CLEAR;
- ret = request_irq(irq, s3c2410fb_irq, IRQF_DISABLED, pdev->name, info);
- if (ret) {
- dev_err(&pdev->dev, "cannot get irq %d - err %d\n", irq, ret);
- ret = -EBUSY;
- goto release_regs;
- }
- info->clk = clk_get(NULL, "lcd");
- if (IS_ERR(info->clk)) {
- printk(KERN_ERR "failed to get lcd clock source\n");
- ret = PTR_ERR(info->clk);
- goto release_irq;
- }
- clk_enable(info->clk); //打開LCD時鐘
- dprintk("got and enabled clock\n");
- msleep(1);
- info->clk_rate = clk_get_rate(info->clk);
- /* find maximum required memory size for display */
- for (i = 0; i < mach_info->num_displays; i++) {
- unsigned long smem_len = mach_info->displays[i].xres;
- smem_len *= mach_info->displays[i].yres;
- smem_len *= mach_info->displays[i].bpp;
- smem_len >>= 3;
- if (fbinfo->fix.smem_len < smem_len)
- fbinfo->fix.smem_len = smem_len;
- }
- //計算顯存大小，並映射DMA資源
- /* Initialize video memory */
- ret = s3c2410fb_map_video_memory(fbinfo);
- if (ret) {
- printk(KERN_ERR "Failed to allocate video RAM: %d\n", ret);
- ret = -ENOMEM;
- goto release_clock;
- }
- dprintk("got video memory\n");
- fbinfo->var.xres = display->xres;
- fbinfo->var.yres = display->yres;
- fbinfo->var.bits_per_pixel = display->bpp;
- //初始化LCD控制器的各個寄存器
- s3c2410fb_init_registers(fbinfo);
- //調整可變參數
- s3c2410fb_check_var(&fbinfo->var, fbinfo);
- ret = s3c2410fb_cpufreq_register(info);
- if (ret < 0) {
- dev_err(&pdev->dev, "Failed to register cpufreq\n");
- goto free_video_memory;
- }
- //註冊幀緩衝結構，也就是把指針賦給一個全局index指針數組
- ret = register_framebuffer(fbinfo);
- if (ret < 0) {
- printk(KERN_ERR "Failed to register framebuffer device: %d\n",
- ret);
- goto free_cpufreq;
- }
- /* create device files */
- ret = device_create_file(&pdev->dev, &dev_attr_debug);
- if (ret) {
- printk(KERN_ERR "failed to add debug attribute\n");
- }
- printk(KERN_INFO "fb%d: %s frame buffer device\n",
- fbinfo->node, fbinfo->fix.id);
- return 0;
- free_cpufreq:
- s3c2410fb_cpufreq_deregister(info);
- free_video_memory:
- s3c2410fb_unmap_video_memory(fbinfo);
- release_clock:
- clk_disable(info->clk);
- clk_put(info->clk);
- release_irq:
- free_irq(irq, info);
- release_regs:
- iounmap(info->io);
- release_mem:
- release_mem_region(res->start, size);
- dealloc_fb:
- platform_set_drvdata(pdev, NULL);
- framebuffer_release(fbinfo);
- return ret;
- }
static int __devinit s3c24xxfb_probe(struct platform_device *pdev,
enum s3c_drv_type drv_type)
{
struct s3c2410fb_info *info; //封裝了fb_info信息的結構
struct s3c2410fb_display *display; //指向定義的lcd信息
struct fb_info *fbinfo;
struct s3c2410fb_mach_info *mach_info; //指向平臺數據
struct resource *res;
int ret;
int irq;
int i;
int size;
u32 lcdcon1;
mach_info = pdev->dev.platform_data;
if (mach_info == NULL) {
dev_err(&pdev->dev,
"no platform data for lcd, cannot attach\n");
return -EINVAL;
}
if (mach_info->default_display >= mach_info->num_displays) {
dev_err(&pdev->dev, "default is %d but only %d displays\n",
mach_info->default_display, mach_info->num_displays);
return -EINVAL;
}
display = mach_info->displays + mach_info->default_display; //指向你定義的lcd信息
irq = platform_get_irq(pdev, 0);
if (irq < 0) {
dev_err(&pdev->dev, "no irq for device\n");
return -ENOENT;
}
fbinfo = framebuffer_alloc(sizeof(struct s3c2410fb_info), &pdev->dev); //分配s3c2410fb_info
if (!fbinfo)
return -ENOMEM;
platform_set_drvdata(pdev, fbinfo);
info = fbinfo->par;
info->dev = &pdev->dev;
info->drv_type = drv_type;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (res == NULL) {
dev_err(&pdev->dev, "failed to get memory registers\n");
ret = -ENXIO;
goto dealloc_fb;
}
size = resource_size(res);
info->mem = request_mem_region(res->start, size, pdev->name);
if (info->mem == NULL) {
dev_err(&pdev->dev, "failed to get memory region\n");
ret = -ENOENT;
goto dealloc_fb;
}
info->io = ioremap(res->start, size);
if (info->io == NULL) {
dev_err(&pdev->dev, "ioremap() of registers failed\n");
ret = -ENXIO;
goto release_mem;
}
info->irq_base = info->io + ((drv_type == DRV_S3C2412) ? S3C2412_LCDINTBASE : S3C2410_LCDINTBASE);
dprintk("devinit\n");
strcpy(fbinfo->fix.id, driver_name);
/* Stop the video */ //關閉顯示器
lcdcon1 = readl(info->io + S3C2410_LCDCON1);
writel(lcdcon1 & ~S3C2410_LCDCON1_ENVID, info->io + S3C2410_LCDCON1);
fbinfo->fix.type = FB_TYPE_PACKED_PIXELS;
fbinfo->fix.type_aux = 0;
fbinfo->fix.xpanstep = 0;
fbinfo->fix.ypanstep = 0;
fbinfo->fix.ywrapstep = 0;
fbinfo->fix.accel = FB_ACCEL_NONE;
fbinfo->var.nonstd = 0;
fbinfo->var.activate = FB_ACTIVATE_NOW;
fbinfo->var.accel_flags = 0;
fbinfo->var.vmode = FB_VMODE_NONINTERLACED;
fbinfo->fbops = &s3c2410fb_ops; //賦值fb操作函數集
fbinfo->flags = FBINFO_FLAG_DEFAULT;
fbinfo->pseudo_palette = &info->pseudo_pal;
for (i = 0; i < 256; i++)
info->palette_buffer[i] = PALETTE_BUFF_CLEAR;
ret = request_irq(irq, s3c2410fb_irq, IRQF_DISABLED, pdev->name, info);
if (ret) {
dev_err(&pdev->dev, "cannot get irq %d - err %d\n", irq, ret);
ret = -EBUSY;
goto release_regs;
}
info->clk = clk_get(NULL, "lcd");
if (IS_ERR(info->clk)) {
printk(KERN_ERR "failed to get lcd clock source\n");
ret = PTR_ERR(info->clk);
goto release_irq;
}
clk_enable(info->clk); //打開LCD時鐘
dprintk("got and enabled clock\n");
msleep(1);
info->clk_rate = clk_get_rate(info->clk);
/* find maximum required memory size for display */
for (i = 0; i < mach_info->num_displays; i++) {
unsigned long smem_len = mach_info->displays[i].xres;
smem_len *= mach_info->displays[i].yres;
smem_len *= mach_info->displays[i].bpp;
smem_len >>= 3;
if (fbinfo->fix.smem_len < smem_len)
fbinfo->fix.smem_len = smem_len;
}
//計算顯存大小，並映射DMA資源
/* Initialize video memory */
ret = s3c2410fb_map_video_memory(fbinfo);
if (ret) {
printk(KERN_ERR "Failed to allocate video RAM: %d\n", ret);
ret = -ENOMEM;
goto release_clock;
}
dprintk("got video memory\n");
fbinfo->var.xres = display->xres;
fbinfo->var.yres = display->yres;
fbinfo->var.bits_per_pixel = display->bpp;
//初始化LCD控制器的各個寄存器
s3c2410fb_init_registers(fbinfo);
//調整可變參數
s3c2410fb_check_var(&fbinfo->var, fbinfo);
ret = s3c2410fb_cpufreq_register(info);
if (ret < 0) {
dev_err(&pdev->dev, "Failed to register cpufreq\n");
goto free_video_memory;
}
//註冊幀緩衝結構，也就是把指針賦給一個全局index指針數組
ret = register_framebuffer(fbinfo);
if (ret < 0) {
printk(KERN_ERR "Failed to register framebuffer device: %d\n",
ret);
goto free_cpufreq;
}
/* create device files */
ret = device_create_file(&pdev->dev, &dev_attr_debug);
if (ret) {
printk(KERN_ERR "failed to add debug attribute\n");
}
printk(KERN_INFO "fb%d: %s frame buffer device\n",
fbinfo->node, fbinfo->fix.id);
return 0;
free_cpufreq:
s3c2410fb_cpufreq_deregister(info);
free_video_memory:
s3c2410fb_unmap_video_memory(fbinfo);
release_clock:
clk_disable(info->clk);
clk_put(info->clk);
release_irq:
free_irq(irq, info);
release_regs:
iounmap(info->io);
release_mem:
release_mem_region(res->start, size);
dealloc_fb:
platform_set_drvdata(pdev, NULL);
framebuffer_release(fbinfo);
return ret;
}- static int __devinit s3c2410fb_map_video_memory(struct fb_info *info)
- {
- struct s3c2410fb_info *fbi = info->par;
- dma_addr_t map_dma;
- unsigned map_size = PAGE_ALIGN(info->fix.smem_len);
- dprintk("map_video_memory(fbi=%p) map_size %u\n", fbi, map_size);
- //將分配的一個寫合併DMA緩衝區設置爲LCD屏幕的虛擬地址
- info->screen_base = dma_alloc_writecombine(fbi->dev, map_size,
- &map_dma, GFP_KERNEL);
- if (info->screen_base) {
- /* prevent initial garbage on screen */
- dprintk("map_video_memory: clear %p:%08x\n",
- info->screen_base, map_size);
- memset(info->screen_base, 0x00, map_size);
- info->fix.smem_start = map_dma;
- dprintk("map_video_memory: dma=%08lx cpu=%p size=%08x\n",
- info->fix.smem_start, info->screen_base, map_size);
- }
- return info->screen_base ? 0 : -ENOMEM;
- }
- static int s3c2410fb_init_registers(struct fb_info *info)
- {
- struct s3c2410fb_info *fbi = info->par;
- struct s3c2410fb_mach_info *mach_info = fbi->dev->platform_data;
- unsigned long flags;
- void __iomem *regs = fbi->io;
- void __iomem *tpal;
- void __iomem *lpcsel;
- if (is_s3c2412(fbi)) {
- tpal = regs + S3C2412_TPAL;
- lpcsel = regs + S3C2412_TCONSEL;
- } else {
- tpal = regs + S3C2410_TPAL;
- lpcsel = regs + S3C2410_LPCSEL;
- }
- /* Initialise LCD with values from haret */
- local_irq_save(flags);
- /* modify the gpio(s) with interrupts set (bjd) */
- //把GPIOC和GPIOD設置爲LCD模式
- modify_gpio(S3C2410_GPCUP, mach_info->gpcup, mach_info->gpcup_mask);
- modify_gpio(S3C2410_GPCCON, mach_info->gpccon, mach_info->gpccon_mask);
- modify_gpio(S3C2410_GPDUP, mach_info->gpdup, mach_info->gpdup_mask);
- modify_gpio(S3C2410_GPDCON, mach_info->gpdcon, mach_info->gpdcon_mask);
- local_irq_restore(flags);
- dprintk("LPCSEL = 0x%08lx\n", mach_info->lpcsel);
- writel(mach_info->lpcsel, lpcsel);
- dprintk("replacing TPAL %08x\n", readl(tpal));
- /* ensure temporary palette disabled */
- writel(0x00, tpal);
- return 0;
- }
- static int s3c2410fb_check_var(struct fb_var_screeninfo *var,
- struct fb_info *info)
- {
- struct s3c2410fb_info *fbi = info->par;
- struct s3c2410fb_mach_info *mach_info = fbi->dev->platform_data;
- struct s3c2410fb_display *display = NULL;
- struct s3c2410fb_display *default_display = mach_info->displays +
- mach_info->default_display;
- int type = default_display->type;
- unsigned i;
- dprintk("check_var(var=%p, info=%p)\n", var, info);
- /* validate x/y resolution */
- /* choose default mode if possible */
- if (var->yres == default_display->yres &&
- var->xres == default_display->xres &&
- var->bits_per_pixel == default_display->bpp)
- display = default_display;
- else
- for (i = 0; i < mach_info->num_displays; i++)
- if (type == mach_info->displays[i].type &&
- var->yres == mach_info->displays[i].yres &&
- var->xres == mach_info->displays[i].xres &&
- var->bits_per_pixel == mach_info->displays[i].bpp) {
- display = mach_info->displays + i;
- break;
- }
- if (!display) {
- dprintk("wrong resolution or depth %dx%d at %d bpp\n",
- var->xres, var->yres, var->bits_per_pixel);
- return -EINVAL;
- }
- //直接賦值給新分配的var
- /* it is always the size as the display */
- var->xres_virtual = display->xres;
- var->yres_virtual = display->yres;
- var->height = display->height;
- var->width = display->width;
- /* copy lcd settings */
- var->pixclock = display->pixclock;
- var->left_margin = display->left_margin;
- var->right_margin = display->right_margin;
- var->upper_margin = display->upper_margin;
- var->lower_margin = display->lower_margin;
- var->vsync_len = display->vsync_len;
- var->hsync_len = display->hsync_len;
- fbi->regs.lcdcon5 = display->lcdcon5;
- /* set display type */
- fbi->regs.lcdcon1 = display->type;
- var->transp.offset = 0;
- var->transp.length = 0;
- /* set r/g/b positions */
- //根據設置的色位模式，設置相應的參數
- switch (var->bits_per_pixel) {
- case 1:
- case 2:
- case 4:
- var->red.offset = 0;
- var->red.length = var->bits_per_pixel;
- var->green = var->red;
- var->blue = var->red;
- break;
- case 8:
- if (display->type != S3C2410_LCDCON1_TFT) {
- /* 8 bpp 332 */
- var->red.length = 3;
- var->red.offset = 5;
- var->green.length = 3;
- var->green.offset = 2;
- var->blue.length = 2;
- var->blue.offset = 0;
- } else {
- var->red.offset = 0;
- var->red.length = 8;
- var->green = var->red;
- var->blue = var->red;
- }
- break;
- case 12:
- /* 12 bpp 444 */
- var->red.length = 4;
- var->red.offset = 8;
- var->green.length = 4;
- var->green.offset = 4;
- var->blue.length = 4;
- var->blue.offset = 0;
- break;
- default:
- case 16:
- if (display->lcdcon5 & S3C2410_LCDCON5_FRM565) {
- /* 16 bpp, 565 format */
- var->red.offset = 11;
- var->green.offset = 5;
- var->blue.offset = 0;
- var->red.length = 5;
- var->green.length = 6;
- var->blue.length = 5;
- } else {
- /* 16 bpp, 5551 format */
- var->red.offset = 11;
- var->green.offset = 6;
- var->blue.offset = 1;
- var->red.length = 5;
- var->green.length = 5;
- var->blue.length = 5;
- }
- break;
- case 32:
- /* 24 bpp 888 and 8 dummy */
- var->red.length = 8;
- var->red.offset = 16;
- var->green.length = 8;
- var->green.offset = 8;
- var->blue.length = 8;
- var->blue.offset = 0;
- break;
- }
- return 0;
- }
static int __devinit s3c2410fb_map_video_memory(struct fb_info *info)
{
struct s3c2410fb_info *fbi = info->par;
dma_addr_t map_dma;
unsigned map_size = PAGE_ALIGN(info->fix.smem_len);
dprintk("map_video_memory(fbi=%p) map_size %u\n", fbi, map_size);
//將分配的一個寫合併DMA緩衝區設置爲LCD屏幕的虛擬地址
info->screen_base = dma_alloc_writecombine(fbi->dev, map_size,
&map_dma, GFP_KERNEL);
if (info->screen_base) {
/* prevent initial garbage on screen */
dprintk("map_video_memory: clear %p:%08x\n",
info->screen_base, map_size);
memset(info->screen_base, 0x00, map_size);
info->fix.smem_start = map_dma;
dprintk("map_video_memory: dma=%08lx cpu=%p size=%08x\n",
info->fix.smem_start, info->screen_base, map_size);
}
return info->screen_base ? 0 : -ENOMEM;
}
static int s3c2410fb_init_registers(struct fb_info *info)
{
struct s3c2410fb_info *fbi = info->par;
struct s3c2410fb_mach_info *mach_info = fbi->dev->platform_data;
unsigned long flags;
void __iomem *regs = fbi->io;
void __iomem *tpal;
void __iomem *lpcsel;
if (is_s3c2412(fbi)) {
tpal = regs + S3C2412_TPAL;
lpcsel = regs + S3C2412_TCONSEL;
} else {
tpal = regs + S3C2410_TPAL;
lpcsel = regs + S3C2410_LPCSEL;
}
/* Initialise LCD with values from haret */
local_irq_save(flags);
/* modify the gpio(s) with interrupts set (bjd) */
//把GPIOC和GPIOD設置爲LCD模式
modify_gpio(S3C2410_GPCUP, mach_info->gpcup, mach_info->gpcup_mask);
modify_gpio(S3C2410_GPCCON, mach_info->gpccon, mach_info->gpccon_mask);
modify_gpio(S3C2410_GPDUP, mach_info->gpdup, mach_info->gpdup_mask);
modify_gpio(S3C2410_GPDCON, mach_info->gpdcon, mach_info->gpdcon_mask);
local_irq_restore(flags);
dprintk("LPCSEL = 0x%08lx\n", mach_info->lpcsel);
writel(mach_info->lpcsel, lpcsel);
dprintk("replacing TPAL %08x\n", readl(tpal));
/* ensure temporary palette disabled */
writel(0x00, tpal);
return 0;
}
static int s3c2410fb_check_var(struct fb_var_screeninfo *var,
struct fb_info *info)
{
struct s3c2410fb_info *fbi = info->par;
struct s3c2410fb_mach_info *mach_info = fbi->dev->platform_data;
struct s3c2410fb_display *display = NULL;
struct s3c2410fb_display *default_display = mach_info->displays +
mach_info->default_display;
int type = default_display->type;
unsigned i;
dprintk("check_var(var=%p, info=%p)\n", var, info);
/* validate x/y resolution */
/* choose default mode if possible */
if (var->yres == default_display->yres &&
var->xres == default_display->xres &&
var->bits_per_pixel == default_display->bpp)
display = default_display;
else
for (i = 0; i < mach_info->num_displays; i++)
if (type == mach_info->displays[i].type &&
var->yres == mach_info->displays[i].yres &&
var->xres == mach_info->displays[i].xres &&
var->bits_per_pixel == mach_info->displays[i].bpp) {
display = mach_info->displays + i;
break;
}
if (!display) {
dprintk("wrong resolution or depth %dx%d at %d bpp\n",
var->xres, var->yres, var->bits_per_pixel);
return -EINVAL;
}
//直接賦值給新分配的var
/* it is always the size as the display */
var->xres_virtual = display->xres;
var->yres_virtual = display->yres;
var->height = display->height;
var->width = display->width;
/* copy lcd settings */
var->pixclock = display->pixclock;
var->left_margin = display->left_margin;
var->right_margin = display->right_margin;
var->upper_margin = display->upper_margin;
var->lower_margin = display->lower_margin;
var->vsync_len = display->vsync_len;
var->hsync_len = display->hsync_len;
fbi->regs.lcdcon5 = display->lcdcon5;
/* set display type */
fbi->regs.lcdcon1 = display->type;
var->transp.offset = 0;
var->transp.length = 0;
/* set r/g/b positions */
//根據設置的色位模式，設置相應的參數
switch (var->bits_per_pixel) {
case 1:
case 2:
case 4:
var->red.offset = 0;
var->red.length = var->bits_per_pixel;
var->green = var->red;
var->blue = var->red;
break;
case 8:
if (display->type != S3C2410_LCDCON1_TFT) {
/* 8 bpp 332 */
var->red.length = 3;
var->red.offset = 5;
var->green.length = 3;
var->green.offset = 2;
var->blue.length = 2;
var->blue.offset = 0;
} else {
var->red.offset = 0;
var->red.length = 8;
var->green = var->red;
var->blue = var->red;
}
break;
case 12:
/* 12 bpp 444 */
var->red.length = 4;
var->red.offset = 8;
var->green.length = 4;
var->green.offset = 4;
var->blue.length = 4;
var->blue.offset = 0;
break;
default:
case 16:
if (display->lcdcon5 & S3C2410_LCDCON5_FRM565) {
/* 16 bpp, 565 format */
var->red.offset = 11;
var->green.offset = 5;
var->blue.offset = 0;
var->red.length = 5;
var->green.length = 6;
var->blue.length = 5;
} else {
/* 16 bpp, 5551 format */
var->red.offset = 11;
var->green.offset = 6;
var->blue.offset = 1;
var->red.length = 5;
var->green.length = 5;
var->blue.length = 5;
}
break;
case 32:
/* 24 bpp 888 and 8 dummy */
var->red.length = 8;
var->red.offset = 16;
var->green.length = 8;
var->green.offset = 8;
var->blue.length = 8;
var->blue.offset = 0;
break;
}
return 0;
}
