帧缓冲驱动程序设计
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显存----
帧缓冲----显示缓存
FrameBuffer从本质上讲是图形设备的硬件抽象。对开发者而言，FrameBuffer是一块显示缓存，往显示缓存中写入特定格式的数据就意味着向屏幕输出内容。通过不断的向frame buffer中写入数据，显示控制器就自动的从frame buffer中取数据并显示出来。
帧缓冲设备对应的设备文件为/dev/fb*，如果系统有多个显示卡，linux下还可支持多个帧缓冲设备，最多可达32个，分别为/dev/fb0到/dev/fb31，而/dev/fb0则为当前缺省的帧缓冲设备，通常指向/dev/fb0。帧缓冲设备为标准字符设备，主设备号为29，次设备号则从0到31.
访问帧缓冲设备---实例演示
1清除LCD
dd if=/dev/zero/fb0 bs=240 count=320 bs-- block size 以块的方式，每个240字节。
2运行应用程序，画图
./lcd
3清除lcd
dd if=/dev/zero of=/dev/fb0 bs=240 count=320
4显示图片
cat 7.bmp>/dev/fb0
-------------------系统架构-----------------------
设备描述
linux内核使用struct fb_info来描述帧缓冲设备。
struct fb_info
{
.................................................................................
struct fb_var_screeninfo var;可变参数
struct fb_fix_screeninfo fix; 固定参数
.................................................................................
struct fb_ops *fbops;帧缓冲操作
....................................................................................
};
可变参数
struct fb_var_screeninfo var记录了用户可以修改的显示参数，包括屏幕分辨率等。
struct fb_var_screeninfo {
__u32 xres; /* visible resolution */
__u32 yres;
__u32 xres_virtual; /* virtual resolution */
__u32 yres_virtual;
__u32 xoffset; /* offset from virtual to visible */
__u32 yoffset; /* resolution */
__u32 bits_per_pixel; /* guess what */
__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 */
__u32 width; /* width of picture in mm */
__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) */
__u32 left_margin; /* time from sync to picture */
__u32 right_margin; /* time from picture to sync */
__u32 upper_margin; /* time from sync to picture */
__u32 lower_margin;
__u32 hsync_len; /* length of horizontal sync */
__u32 vsync_len; /* length of vertical sync */
__u32 sync; /* see FB_SYNC_* */
__u32 vmode; /* see FB_VMODE_* */
__u32 rotate; /* angle we rotate counter clockwise */
__u32 reserved[5]; /* Reserved for future compatibility */
};
固定参数--------
struct fb_fix_screeninfo记录了用户不能修改的显示器控制参数，如显示缓存的物理地址等。
struct fb_fix_screeninfo {
char id[16]; /* identification string eg "TT Builtin" */
unsigned long smem_start; /* Start of frame buffer mem */
/* (physical address) */
__u32 smem_len; /* Length of frame buffer mem */
__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 */
unsigned long mmio_start; /* Start of Memory Mapped I/O */
/* (physical address) */
__u32 mmio_len; /* Length of Memory Mapped I/O */
__u32 accel; /* Indicate to driver which */
/* specific chip/card we have */
__u16 reserved[3]; /* Reserved for future compatibility */
};
操作集
struct fb_ops 包含了对控制器进行操作的函数指针。
若不实现，也可以，这时图中，file_operations结构体中的read等，是内核给我们实现好的。若实现，则会使用自己定义好的。
struct fb_ops {
/* open/release and usage marking */
struct module *owner;
int (*fb_open)(struct fb_info *info, int user);
int (*fb_release)(struct fb_info *info, int user);
/* For framebuffers with strange non linear layouts or that do not
* work with normal memory mapped access
*/
ssize_t (*fb_read)(struct fb_info *info, char __user *buf,
size_t count, loff_t *ppos);
ssize_t (*fb_write)(struct fb_info *info, const char __user *buf,
size_t count, loff_t *ppos);
/* checks var and eventually tweaks it to something supported,
* DO NOT MODIFY PAR */
int (*fb_check_var)(struct fb_var_screeninfo *var, struct fb_info *info);
/* set the video mode according to info->var */
int (*fb_set_par)(struct fb_info *info);
/* set color register */
int (*fb_setcolreg)(unsigned regno, unsigned red, unsigned green,
unsigned blue, unsigned transp, struct fb_info *info);
/* set color registers in batch */
int (*fb_setcmap)(struct fb_cmap *cmap, struct fb_info *info);
/* blank display */
int (*fb_blank)(int blank, struct fb_info *info);
/* pan display */
int (*fb_pan_display)(struct fb_var_screeninfo *var, struct fb_info *info);
/* Draws a rectangle */
void (*fb_fillrect) (struct fb_info *info, const struct fb_fillrect *rect);
/* Copy data from area to another */
void (*fb_copyarea) (struct fb_info *info, const struct fb_copyarea *region);
/* Draws a image to the display */
void (*fb_imageblit) (struct fb_info *info, const struct fb_image *image);
/* Draws cursor */
int (*fb_cursor) (struct fb_info *info, struct fb_cursor *cursor);
/* Rotates the display */
void (*fb_rotate)(struct fb_info *info, int angle);
/* wait for blit idle, optional */
int (*fb_sync)(struct fb_info *info);
/* perform fb specific ioctl (optional) */
int (*fb_ioctl)(struct fb_info *info, unsigned int cmd,
unsigned long arg);
/* Handle 32bit compat ioctl (optional) */
int (*fb_compat_ioctl)(struct fb_info *info, unsigned cmd,
unsigned long arg);
/* perform fb specific mmap */
int (*fb_mmap)(struct fb_info *info, struct vm_area_struct *vma);
/* save current hardware state */
void (*fb_save_state)(struct fb_info *info);
/* restore saved state */
void (*fb_restore_state)(struct fb_info *info);
/* get capability given var */
void (*fb_get_caps)(struct fb_info *info, struct fb_blit_caps *caps,
struct fb_var_screeninfo *var);
};
设备注册
int register_framebuffer(struct fb_info *fb_info)
设备注销
int unregister_framebuffer(struct fb_info *fb_info)
驱动分析-----------------------
/* linux/drivers/video/s3c2410fb.c
* Copyright (c) 2004,2005 Arnaud Patard
* Copyright (c) 2004-2008 Ben Dooks
*
* S3C2410 LCD Framebuffer Driver
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file COPYING in the main directory of this archive for
* more details.
*
* Driver based on skeletonfb.c, sa1100fb.c and others.
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/fb.h>
#include <linux/init.h>
#include <linux/dma-mapping.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <asm/io.h>
#include <asm/div64.h>
#include <asm/mach/map.h>
#include <mach/regs-lcd.h>
#include <mach/regs-gpio.h>
#include <mach/fb.h>
#ifdef CONFIG_PM
#include <linux/pm.h>
#endif
#include "s3c2410fb.h"
/* Debugging stuff */
#ifdef CONFIG_FB_S3C2410_DEBUG
static int debug = 1;
#else
static int debug = 0;
#endif
#define dprintk(msg...) if (debug) { printk(KERN_DEBUG "s3c2410fb: " msg); }
/* useful functions */
static int is_s3c2412(struct s3c2410fb_info *fbi)
{
return (fbi->drv_type == DRV_S3C2412);
}
/* s3c2410fb_set_lcdaddr
*
* initialise lcd controller address pointers
*/
static void s3c2410fb_set_lcdaddr(struct fb_info *info)
{
unsigned long saddr1, saddr2, saddr3;
struct s3c2410fb_info *fbi = info->par;
void __iomem *regs = fbi->io;
saddr1 = info->fix.smem_start >> 1;
saddr2 = info->fix.smem_start;
saddr2 += info->fix.line_length * info->var.yres;
saddr2 >>= 1;
saddr3 = S3C2410_OFFSIZE(0) |
S3C2410_PAGEWIDTH((info->fix.line_length / 2) & 0x3ff);
dprintk("LCDSADDR1 = 0x%08lx\n", saddr1);
dprintk("LCDSADDR2 = 0x%08lx\n", saddr2);
dprintk("LCDSADDR3 = 0x%08lx\n", saddr3);
writel(saddr1, regs + S3C2410_LCDSADDR1);
writel(saddr2, regs + S3C2410_LCDSADDR2);
writel(saddr3, regs + S3C2410_LCDSADDR3);
}
/* s3c2410fb_calc_pixclk()
*
* calculate divisor for clk->pixclk
*/
static unsigned int s3c2410fb_calc_pixclk(struct s3c2410fb_info *fbi,
unsigned long pixclk)
{
unsigned long clk = clk_get_rate(fbi->clk);
unsigned long long div;
/* pixclk is in picoseconds, our clock is in Hz
*
* Hz -> picoseconds is / 10^-12
*/
div = (unsigned long long)clk * pixclk;
div >>= 12; /* div / 2^12 */
do_div(div, 625 * 625UL * 625); /* div / 5^12 */
dprintk("pixclk %ld, divisor is %ld\n", pixclk, (long)div);
return div;
}
/*
* s3c2410fb_check_var():
* Get the video params out of 'var'. If a value doesn't fit, round it up,
* if it's too big, return -EINVAL.
*
*/
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;
}
/* 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 */
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;
}
/* s3c2410fb_calculate_stn_lcd_regs
*
* calculate register values from var settings
*/
static void s3c2410fb_calculate_stn_lcd_regs(const struct fb_info *info,
struct s3c2410fb_hw *regs)
{
const struct s3c2410fb_info *fbi = info->par;
const struct fb_var_screeninfo *var = &info->var;
int type = regs->lcdcon1 & ~S3C2410_LCDCON1_TFT;
int hs = var->xres >> 2;
unsigned wdly = (var->left_margin >> 4) - 1;
unsigned wlh = (var->hsync_len >> 4) - 1;
if (type != S3C2410_LCDCON1_STN4)
hs >>= 1;
switch (var->bits_per_pixel) {
case 1:
regs->lcdcon1 |= S3C2410_LCDCON1_STN1BPP;
break;
case 2:
regs->lcdcon1 |= S3C2410_LCDCON1_STN2GREY;
break;
case 4:
regs->lcdcon1 |= S3C2410_LCDCON1_STN4GREY;
break;
case 8:
regs->lcdcon1 |= S3C2410_LCDCON1_STN8BPP;
hs *= 3;
break;
case 12:
regs->lcdcon1 |= S3C2410_LCDCON1_STN12BPP;
hs *= 3;
break;
default:
/* invalid pixel depth */
dev_err(fbi->dev, "invalid bpp %d\n",
var->bits_per_pixel);
}
/* update X/Y info */
dprintk("setting horz: lft=%d, rt=%d, sync=%d\n",
var->left_margin, var->right_margin, var->hsync_len);
regs->lcdcon2 = S3C2410_LCDCON2_LINEVAL(var->yres - 1);
if (wdly > 3)
wdly = 3;
if (wlh > 3)
wlh = 3;
regs->lcdcon3 = S3C2410_LCDCON3_WDLY(wdly) |
S3C2410_LCDCON3_LINEBLANK(var->right_margin / 8) |
S3C2410_LCDCON3_HOZVAL(hs - 1);
regs->lcdcon4 = S3C2410_LCDCON4_WLH(wlh);
}
/* s3c2410fb_calculate_tft_lcd_regs
*
* calculate register values from var settings
*/
static void s3c2410fb_calculate_tft_lcd_regs(const struct fb_info *info,
struct s3c2410fb_hw *regs)
{
const struct s3c2410fb_info *fbi = info->par;
const struct fb_var_screeninfo *var = &info->var;
switch (var->bits_per_pixel) {
case 1:
regs->lcdcon1 |= S3C2410_LCDCON1_TFT1BPP;
break;
case 2:
regs->lcdcon1 |= S3C2410_LCDCON1_TFT2BPP;
break;
case 4:
regs->lcdcon1 |= S3C2410_LCDCON1_TFT4BPP;
break;
case 8:
regs->lcdcon1 |= S3C2410_LCDCON1_TFT8BPP;
regs->lcdcon5 |= S3C2410_LCDCON5_BSWP |
S3C2410_LCDCON5_FRM565;
regs->lcdcon5 &= ~S3C2410_LCDCON5_HWSWP;
break;
case 16:
regs->lcdcon1 |= S3C2410_LCDCON1_TFT16BPP;
regs->lcdcon5 &= ~S3C2410_LCDCON5_BSWP;
regs->lcdcon5 |= S3C2410_LCDCON5_HWSWP;
break;
case 32:
regs->lcdcon1 |= S3C2410_LCDCON1_TFT24BPP;
regs->lcdcon5 &= ~(S3C2410_LCDCON5_BSWP |
S3C2410_LCDCON5_HWSWP |
S3C2410_LCDCON5_BPP24BL);
break;
default:
/* invalid pixel depth */
dev_err(fbi->dev, "invalid bpp %d\n",
var->bits_per_pixel);
}
/* update X/Y info */
dprintk("setting vert: up=%d, low=%d, sync=%d\n",
var->upper_margin, var->lower_margin, var->vsync_len);
dprintk("setting horz: lft=%d, rt=%d, sync=%d\n",
var->left_margin, var->right_margin, var->hsync_len);
regs->lcdcon2 = S3C2410_LCDCON2_LINEVAL(var->yres - 1) |
S3C2410_LCDCON2_VBPD(var->upper_margin - 1) |
S3C2410_LCDCON2_VFPD(var->lower_margin - 1) |
S3C2410_LCDCON2_VSPW(var->vsync_len - 1);
regs->lcdcon3 = S3C2410_LCDCON3_HBPD(var->right_margin - 1) |
S3C2410_LCDCON3_HFPD(var->left_margin - 1) |
S3C2410_LCDCON3_HOZVAL(var->xres - 1);
regs->lcdcon4 = S3C2410_LCDCON4_HSPW(var->hsync_len - 1);
}
/* s3c2410fb_activate_var
*
* activate (set) the controller from the given framebuffer
* information
*/
static void s3c2410fb_activate_var(struct fb_info *info)
{
struct s3c2410fb_info *fbi = info->par;
void __iomem *regs = fbi->io;
int type = fbi->regs.lcdcon1 & S3C2410_LCDCON1_TFT;
struct fb_var_screeninfo *var = &info->var;
int clkdiv = s3c2410fb_calc_pixclk(fbi, var->pixclock) / 2;
dprintk("%s: var->xres = %d\n", __func__, var->xres);
dprintk("%s: var->yres = %d\n", __func__, var->yres);
dprintk("%s: var->bpp = %d\n", __func__, var->bits_per_pixel);
if (type == S3C2410_LCDCON1_TFT) {
s3c2410fb_calculate_tft_lcd_regs(info, &fbi->regs);
--clkdiv;
if (clkdiv < 0)
clkdiv = 0;
} else {
s3c2410fb_calculate_stn_lcd_regs(info, &fbi->regs);
if (clkdiv < 2)
clkdiv = 2;
}
fbi->regs.lcdcon1 |= S3C2410_LCDCON1_CLKVAL(clkdiv);
/* write new registers */
dprintk("new register set:\n");
dprintk("lcdcon[1] = 0x%08lx\n", fbi->regs.lcdcon1);
dprintk("lcdcon[2] = 0x%08lx\n", fbi->regs.lcdcon2);
dprintk("lcdcon[3] = 0x%08lx\n", fbi->regs.lcdcon3);
dprintk("lcdcon[4] = 0x%08lx\n", fbi->regs.lcdcon4);
dprintk("lcdcon[5] = 0x%08lx\n", fbi->regs.lcdcon5);
writel(fbi->regs.lcdcon1 & ~S3C2410_LCDCON1_ENVID,
regs + S3C2410_LCDCON1);
writel(fbi->regs.lcdcon2, regs + S3C2410_LCDCON2);
writel(fbi->regs.lcdcon3, regs + S3C2410_LCDCON3);
writel(fbi->regs.lcdcon4, regs + S3C2410_LCDCON4);
writel(fbi->regs.lcdcon5, regs + S3C2410_LCDCON5);
/* set lcd address pointers */
s3c2410fb_set_lcdaddr(info);
fbi->regs.lcdcon1 |= S3C2410_LCDCON1_ENVID,
writel(fbi->regs.lcdcon1, regs + S3C2410_LCDCON1);
}
/*
* s3c2410fb_set_par - Alters the hardware state.
* @info: frame buffer structure that represents a single frame buffer
*
*/
static int s3c2410fb_set_par(struct fb_info *info)
{
struct fb_var_screeninfo *var = &info->var;
switch (var->bits_per_pixel) {
case 32:
case 16:
case 12:
info->fix.visual = FB_VISUAL_TRUECOLOR;
break;
case 1:
info->fix.visual = FB_VISUAL_MONO01;
break;
default:
info->fix.visual = FB_VISUAL_PSEUDOCOLOR;
break;
}
info->fix.line_length = (var->xres_virtual * var->bits_per_pixel) / 8;
/* activate this new configuration */
s3c2410fb_activate_var(info);
return 0;
}
static void schedule_palette_update(struct s3c2410fb_info *fbi,
unsigned int regno, unsigned int val)
{
unsigned long flags;
unsigned long irqen;
void __iomem *irq_base = fbi->irq_base;
local_irq_save(flags);
fbi->palette_buffer[regno] = val;
if (!fbi->palette_ready) {
fbi->palette_ready = 1;
/* enable IRQ */
irqen = readl(irq_base + S3C24XX_LCDINTMSK);
irqen &= ~S3C2410_LCDINT_FRSYNC;
writel(irqen, irq_base + S3C24XX_LCDINTMSK);
}
local_irq_restore(flags);
}
/* from pxafb.c */
static inline unsigned int chan_to_field(unsigned int chan,
struct fb_bitfield *bf)
{
chan &= 0xffff;
chan >>= 16 - bf->length;
return chan << bf->offset;
}
static int s3c2410fb_setcolreg(unsigned regno,
unsigned red, unsigned green, unsigned blue,
unsigned transp, struct fb_info *info)
{
struct s3c2410fb_info *fbi = info->par;
void __iomem *regs = fbi->io;
unsigned int val;
/* dprintk("setcol: regno=%d, rgb=%d,%d,%d\n",
regno, red, green, blue); */
switch (info->fix.visual) {
case FB_VISUAL_TRUECOLOR:
/* true-colour, use pseudo-palette */
if (regno < 16) {
u32 *pal = info->pseudo_palette;
val = chan_to_field(red, &info->var.red);
val |= chan_to_field(green, &info->var.green);
val |= chan_to_field(blue, &info->var.blue);
pal[regno] = val;
}
break;
case FB_VISUAL_PSEUDOCOLOR:
if (regno < 256) {
/* currently assume RGB 5-6-5 mode */
val = (red >> 0) & 0xf800;
val |= (green >> 5) & 0x07e0;
val |= (blue >> 11) & 0x001f;
writel(val, regs + S3C2410_TFTPAL(regno));
schedule_palette_update(fbi, regno, val);
}
break;
default:
return 1; /* unknown type */
}
return 0;
}
/* s3c2410fb_lcd_enable
*
* shutdown the lcd controller
*/
static void s3c2410fb_lcd_enable(struct s3c2410fb_info *fbi, int enable)
{
unsigned long flags;
local_irq_save(flags);
if (enable)
fbi->regs.lcdcon1 |= S3C2410_LCDCON1_ENVID;
else
fbi->regs.lcdcon1 &= ~S3C2410_LCDCON1_ENVID;
writel(fbi->regs.lcdcon1, fbi->io + S3C2410_LCDCON1);
local_irq_restore(flags);
}
/*
* s3c2410fb_blank
* @blank_mode: the blank mode we want.
* @info: frame buffer structure that represents a single frame buffer
*
* Blank the screen if blank_mode != 0, else unblank. Return 0 if
* blanking succeeded, != 0 if un-/blanking failed due to e.g. a
* video mode which doesn't support it. Implements VESA suspend
* and powerdown modes on hardware that supports disabling hsync/vsync:
*
* Returns negative errno on error, or zero on success.
*
*/
static int s3c2410fb_blank(int blank_mode, struct fb_info *info)
{
struct s3c2410fb_info *fbi = info->par;
void __iomem *tpal_reg = fbi->io;
dprintk("blank(mode=%d, info=%p)\n", blank_mode, info);
tpal_reg += is_s3c2412(fbi) ? S3C2412_TPAL : S3C2410_TPAL;
if (blank_mode == FB_BLANK_POWERDOWN) {
s3c2410fb_lcd_enable(fbi, 0);
} else {
s3c2410fb_lcd_enable(fbi, 1);
}
if (blank_mode == FB_BLANK_UNBLANK)
writel(0x0, tpal_reg);
else {
dprintk("setting TPAL to output 0x000000\n");
writel(S3C2410_TPAL_EN, tpal_reg);
}
return 0;
}
static int s3c2410fb_debug_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
return snprintf(buf, PAGE_SIZE, "%s\n", debug ? "on" : "off");
}
static int s3c2410fb_debug_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t len)
{
if (len < 1)
return -EINVAL;
if (strnicmp(buf, "on", 2) == 0 ||
strnicmp(buf, "1", 1) == 0) {
debug = 1;
printk(KERN_DEBUG "s3c2410fb: Debug On");
} else if (strnicmp(buf, "off", 3) == 0 ||
strnicmp(buf, "0", 1) == 0) {
debug = 0;
printk(KERN_DEBUG "s3c2410fb: Debug Off");
} else {
return -EINVAL;
}
return len;
}
static DEVICE_ATTR(debug, 0666, s3c2410fb_debug_show, s3c2410fb_debug_store);
static struct fb_ops s3c2410fb_ops = {
.owner = THIS_MODULE,
.fb_check_var = s3c2410fb_check_var,
.fb_set_par = s3c2410fb_set_par,
.fb_blank = s3c2410fb_blank,
.fb_setcolreg = s3c2410fb_setcolreg,
.fb_fillrect = cfb_fillrect,
.fb_copyarea = cfb_copyarea,
.fb_imageblit = cfb_imageblit,
};
/*
* s3c2410fb_map_video_memory():
* Allocates the DRAM memory for the frame buffer. This buffer is
* remapped into a non-cached, non-buffered, memory region to
* allow palette and pixel writes to occur without flushing the
* cache. Once this area is remapped, all virtual memory
* access to the video memory should occur at the new region.
*/
static int __init 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);
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 inline void s3c2410fb_unmap_video_memory(struct fb_info *info)
{
struct s3c2410fb_info *fbi = info->par;
dma_free_writecombine(fbi->dev, PAGE_ALIGN(info->fix.smem_len),
info->screen_base, info->fix.smem_start);
}
static inline void modify_gpio(void __iomem *reg,
unsigned long set, unsigned long mask)
{
unsigned long tmp;
tmp = readl(reg) & ~mask;
writel(tmp | set, reg);
}
/*
* s3c2410fb_init_registers - Initialise all LCD-related registers
*/
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) */
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 void s3c2410fb_write_palette(struct s3c2410fb_info *fbi)
{
unsigned int i;
void __iomem *regs = fbi->io;
fbi->palette_ready = 0;
for (i = 0; i < 256; i++) {
unsigned long ent = fbi->palette_buffer[i];
if (ent == PALETTE_BUFF_CLEAR)
continue;
writel(ent, regs + S3C2410_TFTPAL(i));
/* it seems the only way to know exactly
* if the palette wrote ok, is to check
* to see if the value verifies ok
*/
if (readw(regs + S3C2410_TFTPAL(i)) == ent)
fbi->palette_buffer[i] = PALETTE_BUFF_CLEAR;
else
fbi->palette_ready = 1; /* retry */
}
}
static irqreturn_t s3c2410fb_irq(int irq, void *dev_id)
{
struct s3c2410fb_info *fbi = dev_id;
void __iomem *irq_base = fbi->irq_base;
unsigned long lcdirq = readl(irq_base + S3C24XX_LCDINTPND);
if (lcdirq & S3C2410_LCDINT_FRSYNC) {
if (fbi->palette_ready)
s3c2410fb_write_palette(fbi);
writel(S3C2410_LCDINT_FRSYNC, irq_base + S3C24XX_LCDINTPND);
writel(S3C2410_LCDINT_FRSYNC, irq_base + S3C24XX_LCDSRCPND);
}
return IRQ_HANDLED;
}
static char driver_name[] = "s3c2410fb";
static int __init s3c24xxfb_probe(struct platform_device *pdev,
enum s3c_drv_type drv_type)
{
struct s3c2410fb_info *info;
struct s3c2410fb_display *display;
struct fb_info *fbinfo;
struct s3c2410fb_mach_info *mach_info;
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;
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);
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 = (res->end - res->start) + 1;
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 */
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;
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 (!info->clk || IS_ERR(info->clk)) {
printk(KERN_ERR "failed to get lcd clock source\n");
ret = -ENOENT;
goto release_irq;
}
clk_enable(info->clk);
dprintk("got and enabled clock\n");
msleep(1);
/* 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;
}
/* 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;
s3c2410fb_init_registers(fbinfo);
s3c2410fb_check_var(&fbinfo->var, fbinfo);
ret = register_framebuffer(fbinfo);
if (ret < 0) {
printk(KERN_ERR "Failed to register framebuffer device: %d\n",
ret);
goto free_video_memory;
}
/* 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_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_resource(info->mem);
kfree(info->mem);
dealloc_fb:
platform_set_drvdata(pdev, NULL);
framebuffer_release(fbinfo);
return ret;
}
static int __init s3c2410fb_probe(struct platform_device *pdev)
{
return s3c24xxfb_probe(pdev, DRV_S3C2410);
}
static int __init s3c2412fb_probe(struct platform_device *pdev)
{
return s3c24xxfb_probe(pdev, DRV_S3C2412);
}
/*
* Cleanup
*/
static int s3c2410fb_remove(struct platform_device *pdev)
{
struct fb_info *fbinfo = platform_get_drvdata(pdev);
struct s3c2410fb_info *info = fbinfo->par;
int irq;
unregister_framebuffer(fbinfo);
s3c2410fb_lcd_enable(info, 0);
msleep(1);
s3c2410fb_unmap_video_memory(fbinfo);
if (info->clk) {
clk_disable(info->clk);
clk_put(info->clk);
info->clk = NULL;
}
irq = platform_get_irq(pdev, 0);
free_irq(irq, info);
iounmap(info->io);
release_resource(info->mem);
kfree(info->mem);
platform_set_drvdata(pdev, NULL);
framebuffer_release(fbinfo);
return 0;
}
#ifdef CONFIG_PM
/* suspend and resume support for the lcd controller */
static int s3c2410fb_suspend(struct platform_device *dev, pm_message_t state)
{
struct fb_info *fbinfo = platform_get_drvdata(dev);
struct s3c2410fb_info *info = fbinfo->par;
s3c2410fb_lcd_enable(info, 0);
/* sleep before disabling the clock, we need to ensure
* the LCD DMA engine is not going to get back on the bus
* before the clock goes off again (bjd) */
msleep(1);
clk_disable(info->clk);
return 0;
}
static int s3c2410fb_resume(struct platform_device *dev)
{
struct fb_info *fbinfo = platform_get_drvdata(dev);
struct s3c2410fb_info *info = fbinfo->par;
clk_enable(info->clk);
msleep(1);
s3c2410fb_init_registers(fbinfo);
return 0;
}
#else
#define s3c2410fb_suspend NULL
#define s3c2410fb_resume NULL
#endif
static struct platform_driver s3c2410fb_driver = {
.probe = s3c2410fb_probe,
.remove = s3c2410fb_remove,
.suspend = s3c2410fb_suspend,
.resume = s3c2410fb_resume,
.driver = {
.name = "s3c2410-lcd",
.owner = THIS_MODULE,
},
};
static struct platform_driver s3c2412fb_driver = {
.probe = s3c2412fb_probe,
.remove = s3c2410fb_remove,
.suspend = s3c2410fb_suspend,
.resume = s3c2410fb_resume,
.driver = {
.name = "s3c2412-lcd",
.owner = THIS_MODULE,
},
};
int __init s3c2410fb_init(void)
{
int ret = platform_driver_register(&s3c2410fb_driver);
if (ret == 0)
ret = platform_driver_register(&s3c2412fb_driver);;
return ret;
}
static void __exit s3c2410fb_cleanup(void)
{
platform_driver_unregister(&s3c2410fb_driver);
platform_driver_unregister(&s3c2412fb_driver);
}
module_init(s3c2410fb_init);
module_exit(s3c2410fb_cleanup);
MODULE_AUTHOR("Arnaud Patard <arnaud.patard@rtp-net.org>, "
"Ben Dooks <ben-linux@fluff.org>");
MODULE_DESCRIPTION("Framebuffer driver for the s3c2410");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:s3c2410-lcd");
MODULE_ALIAS("platform:s3c2412-lcd");
lcd驱动程序测试-----------
配置s3c2440 lcd驱动程序
make menuconfig ARCH=arm
device drivers------s3c2410 frame buffer support-----3.5 2410 nec support
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