fbmem.c

该程序是在linux arm下实现的基于framebuffer的LCD驱动

/*
 *  linux/drivers/video/fbmem.c
 *
 *  Copyright (C) 1994 Martin Schaller
 *
 *	2001 - Documented with DocBook
 *	- Brad Douglas <[e-mail]>
 *
 * 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.
 */

#include <linux/config.h>
#include <linux/module.h>

#include <linux/types.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/smp_lock.h>
#include <linux/kernel.h>
#include <linux/major.h>
#include <linux/slab.h>
#include <linux/mman.h>
#include <linux/tty.h>
#include <linux/console.h>
#include <linux/init.h>
#include <linux/proc_fs.h>
#ifdef CONFIG_KMOD
#include <linux/kmod.h>
#endif
#include <linux/devfs_fs_kernel.h>

#if defined(__mc68000__) || defined(CONFIG_APUS)
#include <asm/setup.h>
#endif

#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/page.h>
#include <asm/pgtable.h>

#include <linux/fb.h>
#include <video/fbcon.h>

    /*
     *  Frame buffer device initialization and setup routines
     */

extern int acornfb_init(void);
extern int acornfb_setup(char*);
extern int amifb_init(void);
extern int amifb_setup(char*);
extern int atafb_init(void);
extern int atafb_setup(char*);
extern int macfb_init(void);
extern int macfb_setup(char*);
extern int cyberfb_init(void);
extern int cyberfb_setup(char*);
extern int pm2fb_init(void);
extern int pm2fb_setup(char*);
extern int pm3fb_init(void);
extern int pm3fb_setup(char*);
extern int cyber2000fb_init(void);
extern int retz3fb_init(void);
extern int retz3fb_setup(char*);
extern int clgenfb_init(void);
extern int clgenfb_setup(char*);
extern int hitfb_init(void);
extern int vfb_init(void);
extern int vfb_setup(char*);
extern int offb_init(void);
extern int atyfb_init(void);
extern int atyfb_setup(char*);
extern int aty128fb_init(void);
extern int aty128fb_setup(char*);
extern int neofb_init(void);
extern int neofb_setup(char*);
extern int igafb_init(void);
extern int igafb_setup(char*);
extern int imsttfb_init(void);
extern int imsttfb_setup(char*);
extern int dnfb_init(void);
extern int tgafb_init(void);
extern int tgafb_setup(char*);
extern int virgefb_init(void);
extern int virgefb_setup(char*);
extern int resolver_video_setup(char*);
extern int s3triofb_init(void);
extern int vesafb_init(void);
extern int vesafb_setup(char*);
extern int vga16fb_init(void);
extern int vga16fb_setup(char*);
extern int hgafb_init(void);
extern int hgafb_setup(char*);
extern int matroxfb_init(void);
extern int matroxfb_setup(char*);
extern int hpfb_init(void);
extern int sbusfb_init(void);
extern int sbusfb_setup(char*);
extern int control_init(void);
extern int control_setup(char*);
extern int platinum_init(void);
extern int platinum_setup(char*);
extern int valkyriefb_init(void);
extern int valkyriefb_setup(char*);
extern int chips_init(void);
extern int g364fb_init(void);
extern int sa1100fb_init(void);
extern int fm2fb_init(void);
extern int fm2fb_setup(char*);
extern int q40fb_init(void);
extern int sun3fb_init(void);
extern int sun3fb_setup(char *);
extern int sgivwfb_init(void);
extern int sgivwfb_setup(char*);
extern int rivafb_init(void);
extern int rivafb_setup(char*);
extern int tdfxfb_init(void);
extern int tdfxfb_setup(char*);
extern int tridentfb_init(void);
extern int tridentfb_setup(char*);
extern int sisfb_init(void);
extern int sisfb_setup(char*);
extern int stifb_init(void);
extern int stifb_setup(char*);
extern int pmagbafb_init(void);
extern int pmagbbfb_init(void);
extern void maxinefb_init(void);
extern int tx3912fb_init(void);
extern int radeonfb_init(void);
extern int radeonfb_setup(char*);
extern int e1355fb_init(void);
extern int e1355fb_setup(char*);
extern int au1100fb_init(void);
extern int au1100fb_setup(char*);
extern int pvr2fb_init(void);
extern int pvr2fb_setup(char*);
extern int sstfb_init(void);
extern int sstfb_setup(char*);

/*
 * 配置各种显示设备的数据结构
 */
static struct {
	const char *name;	//设备名称
	int (*init)(void);	//指向设备初始化函数
	int (*setup)(char*);//指向设备安装函数
} fb_drivers[] __initdata = {

#ifdef CONFIG_FB_SBUS
	/*
	 * Sbusfb must be initialized _before_ other frame buffer devices that
	 * use PCI probing
	 */
	{ "sbus", sbusfb_init, sbusfb_setup },
#endif

	/*
	 * Chipset specific drivers that use resource management
	 */

#ifdef CONFIG_FB_RETINAZ3
	{ "retz3", retz3fb_init, retz3fb_setup },
#endif
#ifdef CONFIG_FB_AMIGA
	{ "amifb", amifb_init, amifb_setup },
#endif
#ifdef CONFIG_FB_CYBER
	{ "cyber", cyberfb_init, cyberfb_setup },
#endif
#ifdef CONFIG_FB_CYBER2000
	{ "cyber2000", cyber2000fb_init, NULL },
#endif
#ifdef CONFIG_FB_PM2
	{ "pm2fb", pm2fb_init, pm2fb_setup },
#endif
#ifdef CONFIG_FB_PM3
	{ "pm3fb", pm3fb_init, pm3fb_setup },
#endif
#ifdef CONFIG_FB_CLGEN
	{ "clgen", clgenfb_init, clgenfb_setup },
#endif
#ifdef CONFIG_FB_ATY
	{ "atyfb", atyfb_init, atyfb_setup },
#endif
#ifdef CONFIG_FB_MATROX
	{ "matrox", matroxfb_init, matroxfb_setup },
#endif
#ifdef CONFIG_FB_ATY128
	{ "aty128fb", aty128fb_init, aty128fb_setup },
#endif
#ifdef CONFIG_FB_NEOMAGIC
	{ "neo", neofb_init, neofb_setup },
#endif
#ifdef CONFIG_FB_VIRGE
	{ "virge", virgefb_init, virgefb_setup },
#endif
#ifdef CONFIG_FB_RIVA
	{ "riva", rivafb_init, rivafb_setup },
#endif
#ifdef CONFIG_FB_RADEON
	{ "radeon", radeonfb_init, radeonfb_setup },
#endif
#ifdef CONFIG_FB_CONTROL
	{ "controlfb", control_init, control_setup },
#endif
#ifdef CONFIG_FB_PLATINUM
	{ "platinumfb", platinum_init, platinum_setup },
#endif
#ifdef CONFIG_FB_VALKYRIE
	{ "valkyriefb", valkyriefb_init, valkyriefb_setup },
#endif
#ifdef CONFIG_FB_CT65550
	{ "chipsfb", chips_init, NULL },
#endif
#ifdef CONFIG_FB_IMSTT
	{ "imsttfb", imsttfb_init, imsttfb_setup },
#endif
#ifdef CONFIG_FB_S3TRIO
	{ "s3trio", s3triofb_init, NULL },
#endif 
#ifdef CONFIG_FB_FM2
	{ "fm2fb", fm2fb_init, fm2fb_setup },
#endif 
#ifdef CONFIG_FB_SIS
	{ "sisfb", sisfb_init, sisfb_setup },
#endif
#ifdef CONFIG_FB_TRIDENT
	{ "trident", tridentfb_init, tridentfb_setup },
#endif
#ifdef CONFIG_FB_VOODOO1
	{ "sst", sstfb_init, sstfb_setup },
#endif

	/*
	 * Generic drivers that are used as fallbacks
	 * 
	 * These depend on resource management and must be initialized
	 * _after_ all other frame buffer devices that use resource
	 * management!
	 */

#ifdef CONFIG_FB_OF
	{ "offb", offb_init, NULL },
#endif
#ifdef CONFIG_FB_VESA
	{ "vesa", vesafb_init, vesafb_setup },
#endif 

	/*
	 * Chipset specific drivers that don't use resource management (yet)
	 */

#ifdef CONFIG_FB_3DFX
	{ "tdfx", tdfxfb_init, tdfxfb_setup },
#endif
#ifdef CONFIG_FB_SGIVW
	{ "sgivw", sgivwfb_init, sgivwfb_setup },
#endif
#ifdef CONFIG_FB_ACORN
	{ "acorn", acornfb_init, acornfb_setup },
#endif
#ifdef CONFIG_FB_ATARI
	{ "atafb", atafb_init, atafb_setup },
#endif
#ifdef CONFIG_FB_MAC
	{ "macfb", macfb_init, macfb_setup },
#endif
#ifdef CONFIG_FB_HGA
	{ "hga", hgafb_init, hgafb_setup },
#endif 
#ifdef CONFIG_FB_IGA
	{ "igafb", igafb_init, igafb_setup },
#endif
#ifdef CONFIG_APOLLO
	{ "apollo", dnfb_init, NULL },
#endif
#ifdef CONFIG_FB_Q40
	{ "q40fb", q40fb_init, NULL },
#endif
#ifdef CONFIG_FB_TGA
	{ "tga", tgafb_init, tgafb_setup },
#endif
#ifdef CONFIG_FB_HP300
	{ "hpfb", hpfb_init, NULL },
#endif 
#ifdef CONFIG_FB_G364
	{ "g364", g364fb_init, NULL },
#endif
#ifdef CONFIG_FB_SA1100
	{ "sa1100", sa1100fb_init, NULL },
#endif
#ifdef CONFIG_FB_SUN3
	{ "sun3", sun3fb_init, sun3fb_setup },
#endif
#ifdef CONFIG_FB_HIT
	{ "hitfb", hitfb_init, NULL },
#endif
#ifdef CONFIG_FB_TX3912
	{ "tx3912", tx3912fb_init, NULL },
#endif
#ifdef CONFIG_FB_E1355
	{ "e1355fb", e1355fb_init, e1355fb_setup },
#endif
#ifdef CONFIG_FB_PVR2
	{ "pvr2", pvr2fb_init, pvr2fb_setup },
#endif
#ifdef CONFIG_FB_PMAG_BA
	{ "pmagbafb", pmagbafb_init, NULL },
#endif
#ifdef CONFIG_FB_PMAGB_B
	{ "pmagbbfb", pmagbbfb_init, NULL },
#endif
#ifdef CONFIG_FB_MAXINE
	{ "maxinefb", maxinefb_init, NULL },
#endif
#ifdef CONFIG_FB_AU1100
	{ "au1100fb", au1100fb_init, au1100fb_setup },
#endif 


	/*
	 * Generic drivers that don't use resource management (yet)
	 */

#ifdef CONFIG_FB_VGA16
	{ "vga16", vga16fb_init, vga16fb_setup },
#endif 
#ifdef CONFIG_FB_STI
	{ "stifb", stifb_init, stifb_setup },
#endif

#ifdef CONFIG_GSP_RESOLVER
	/* Not a real frame buffer device... */
	{ "resolver", NULL, resolver_video_setup },
#endif

#ifdef CONFIG_FB_VIRTUAL
	/*
	 * Vfb must be last to avoid that it becomes your primary display if
	 * other display devices are present
	 */
	{ "vfb", vfb_init, vfb_setup },
#endif
};

/*
 * 定义表示设备数目的常量
 */
#define NUM_FB_DRIVERS	(sizeof(fb_drivers)/sizeof(*fb_drivers))

extern const char *global_mode_option;

static initcall_t pref_init_funcs[FB_MAX];
static int num_pref_init_funcs __initdata = 0;

//registered_fb:指向已登记入内核的设备的fb_info结构的数组
struct fb_info *registered_fb[FB_MAX];
int num_registered_fb;
extern int fbcon_softback_size; 

static int first_fb_vc;
static int last_fb_vc = MAX_NR_CONSOLES-1;
static int fbcon_is_default = 1;

#ifdef CONFIG_FB_OF
static int ofonly __initdata = 0;
#endif

/*
 * 
 */
static int fbmem_read_proc(char *buf, char **start, off_t offset,
			   int len, int *eof, void *private)
{
	struct fb_info **fi;
	int clen;
	clen = 0;

	/*
	 * 将已登记的各个显示设备的设备号及名称写到buf+clen的位置，
	 * 其中clen记录了已登记的设备信息的字节数
	 */
	for (fi = registered_fb; fi < &registered_fb[FB_MAX] && len < 4000; fi++)
		if (*fi)
			clen += sprintf(buf + clen, "%d %s\n",
				        GET_FB_IDX((*fi)->node),
				        (*fi)->modename);

	*start = buf + offset;	//FB中用于显示信息的内存的起始地址

	if (clen > offset)
		clen -= offset;
	else
		clen = 0;
	return clen < len ? clen : len;
}

/*
 * 将file指向的FB中、ppos位置开始的的count个字节读入buf中
 */
static ssize_t
fb_read(struct file *file, char *buf, size_t count, loff_t *ppos)
{
	unsigned long p = *ppos;
	// 获取设备节点
	struct inode *inode = file->f_dentry->d_inode;

	/* 以下语句用于指向可对FB进行底层操作的函数 */
	int fbidx = GET_FB_IDX(inode->i_rdev);
	struct fb_info *info = registered_fb[fbidx];
	struct fb_ops *fb = info->fbops;

	struct fb_fix_screeninfo fix;
	
	// 若未找到可对FB进行底层操作的函数或设备不可显示，则出错返回
	if (! fb || ! info->disp)
		return -ENODEV;

	// 用fix指向FB的不可修改信息
	fb->fb_get_fix(&fix,PROC_CONSOLE(info), info);

	// 起始位置p不合法，返回
	if (p >= fix.smem_len)
	    return 0;

	// 需要传输的字节数connt大于FB的容量，调整count值至FB的最大容量
	if (count >= fix.smem_len)
	    count = fix.smem_len;

	// 从起始位置开始后的count字节超出FB的范围，调整count值
	if (count + p > fix.smem_len)
		count = fix.smem_len - p;

	// count值合法，进行字节传输
	if (count) {
	    char *base_addr;
	    base_addr = info->disp->screen_base;

	    count -= copy_to_user(buf, base_addr+p, count);

	    if (!count)
	    	return -EFAULT;
	    *ppos += count;	// 修改起始位置
	}
	return count;
}

/*
 * 将buf中count个字节写入到file指向的FB的ppos位置处
 */
static ssize_t
fb_write(struct file *file, const char *buf, size_t count, loff_t *ppos)
{
	unsigned long p = *ppos;
	struct inode *inode = file->f_dentry->d_inode;
	int fbidx = GET_FB_IDX(inode->i_rdev);
	struct fb_info *info = registered_fb[fbidx];
	struct fb_ops *fb = info->fbops;

	struct fb_fix_screeninfo fix;
	int err;

	if (! fb || ! info->disp)
		return -ENODEV;

	fb->fb_get_fix(&fix, PROC_CONSOLE(info), info);

	if (p > fix.smem_len)
	    return -ENOSPC;
	if (count >= fix.smem_len)
	    count = fix.smem_len;
	err = 0;
	if (count + p > fix.smem_len) {
	    count = fix.smem_len - p;
	    err = -ENOSPC;
	}

	if (count) {
	    char *base_addr;

	    base_addr = info->disp->screen_base;
	    count -= copy_from_user(base_addr+p, buf, count);
	    *ppos += count;
	    err = -EFAULT;
	}
	if (count)
		return count;
	return err;
}

/*
 * 加载设备fbn，其中n从0到31
 */
#ifdef CONFIG_KMOD
static void try_to_load(int fb)
{
	char modname[16];

	sprintf(modname, "fb%d", fb);
	request_module(modname);
}
#endif /* CONFIG_KMOD */

/*
 * 
 */
static int 
fb_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
	 unsigned long arg)
{
	int fbidx = GET_FB_IDX(inode->i_rdev);
	struct fb_info *info = registered_fb[fbidx];
	struct fb_ops *fb = info->fbops;

	struct fb_cmap cmap;
	struct fb_var_screeninfo var;