uboot-imx RGB24分析

在mx6q_sabrsd.c文件中
函数else if(strcmp(s, "YUV444") == 0)
val = IPU_PIX_FMT_YUV444;
else
val = IPU_PIX_FMT_RGB666;
printf("fixfmt = %s %d\n", s, val); ，其中val=RGB24 di=1 lvsd=fb_videomode
ret = ipuv3_fb_init(&lvds_xga, di, val,
DI_PCLK_LDB, 65000000);
此后进入ipuv3_fb_init这个函数
分析发现ret = ipuv3_fb_init(&lvds_xga, di, val,DI_PCLK_LDB, 65000000);

int ipuv3_fb_init(struct fb_videomode *mode, int di, int interface_pix_fmt(即是val),
ipu_di_clk_parent_t di_clk_parent, int di_clk_val)
{
int ret;

ret = ipu_probe(di, di_clk_parent, di_clk_val);
if (ret)
puts("Error initializing IPU\n");

debug("Framebuffer at 0x%x\n", (unsigned int)lcd_base);
ret = mxcfb_probe(interface_pix_fmt, mode, di);

return ret;
}
interface_pix_fmt==RGB24
struct fb_videomode *mode ==&lvds_xga
di ==1
发现mxcfb_probe这个函数设计到了RGB24==interface_pix_fmt, 的形式
此时我们再进入mxcfb_probe这个函数分析
static int mxcfb_probe(u32 interface_pix_fmt, struct fb_videomode *mode, int di)
{
struct fb_info *fbi;
struct mxcfb_info *mxcfbi;
int ret = 0;

/*
* Initialize FB structures
*/
fbi = mxcfb_init_fbinfo();
if (!fbi) {
ret = -ENOMEM;
goto err0;
}
mxcfbi = (struct mxcfb_info *)fbi->par;

if (!g_dp_in_use) {
mxcfbi->ipu_ch = MEM_BG_SYNC;
mxcfbi->blank = FB_BLANK_UNBLANK;
} else {
mxcfbi->ipu_ch = MEM_DC_SYNC;
mxcfbi->blank = FB_BLANK_POWERDOWN;
}

mxcfbi->ipu_di = di;

ipu_disp_set_global_alpha(mxcfbi->ipu_ch, 1, 0x80);
ipu_disp_set_color_key(mxcfbi->ipu_ch, 0, 0);
strcpy(fbi->fix.id, "DISP3 BG");

g_dp_in_use = 1;

mxcfb_info[mxcfbi->ipu_di] = fbi;

/* Need dummy values until real panel is configured */
fbi->var.xres = 640;
fbi->var.yres = 480;
fbi->var.bits_per_pixel = 16;

发现在这个地方RGB24被赋值给了mxcfbi->ipu_di_pix_fmt，我们再来分析mxcfbi这个函数

mxcfbi->ipu_di_pix_fmt = interface_pix_fmt;//RGB24
fb_videomode_to_var(&fbi->var, mode);

mxcfb_check_var(&fbi->var, fbi);

/* Default Y virtual size is 2x panel size */
fbi->var.yres_virtual = fbi->var.yres * 2;

mxcfb_set_fix(fbi);

/* alocate fb first */
if (mxcfb_map_video_memory(fbi) < 0)
return -ENOMEM;

mxcfb_set_par(fbi);

/* Setting panel_info for lcd */
panel_info.vl_col = fbi->var.xres;
panel_info.vl_row = fbi->var.yres;
panel_info.vl_bpix = LCD_BPP;

lcd_line_length = (panel_info.vl_col * NBITS(panel_info.vl_bpix)) / 8;

debug("MXC IPUV3 configured\n"
"XRES = %d YRES = %d BitsXpixel = %d\n",
panel_info.vl_col,
panel_info.vl_row,
panel_info.vl_bpix);

ipu_dump_registers();

return 0;

err0:
return ret;
}

我们在mxc_ipuv3_fb.c这个文件中发现了mxcfbi的定义

struct mxcfb_info {
int blank;
ipu_channel_t ipu_ch;
int ipu_di;
u32 ipu_di_pix_fmt;
unsigned char overlay;
unsigned char alpha_chan_en;
dma_addr_t alpha_phy_addr0;
dma_addr_t alpha_phy_addr1;
void *alpha_virt_addr0;
void *alpha_virt_addr1;
uint32_t alpha_mem_len;
uint32_t cur_ipu_buf;
uint32_t cur_ipu_alpha_buf;

u32 pseudo_palette[16];
};

struct fb_info {

struct fb_var_screeninfo var; /* Current var */
unsigned long smem_start; /* Start of frame buffer mem */
/* (physical address) */
unsigned int smem_len; /* Length of frame buffer mem */
unsigned int type; /* see FB_TYPE_* */
unsigned int line_length; /* length of a line in bytes */

char *screen_base;
unsigned long screen_size;
int logo_height;
unsigned int logo_size;
};