arcfb.c

Linux环境下视频显示卡设备的驱动程序源代码

/*
 * linux/drivers/video/arcfb.c -- FB driver for Arc monochrome LCD board
 *
 * Copyright (C) 2005, Jaya Kumar <[e-mail]>
 * http://www.intworks.biz/arclcd
 *
 * 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.
 *
 * Layout is based on skeletonfb.c by James Simmons and Geert Uytterhoeven.
 *
 * This driver was written to be used with the Arc LCD board. Arc uses a
 * set of KS108 chips that control individual 64x64 LCD matrices. The board
 * can be paneled in a variety of setups such as 2x1=128x64, 4x4=256x256 and
 * so on. The interface between the board and the host is TTL based GPIO. The
 * GPIO requirements are 8 writable data lines and 4+n lines for control. On a
 * GPIO-less system, the board can be tested by connecting the respective sigs
 * up to a parallel port connector. The driver requires the IO addresses for
 * data and control GPIO at load time. It is unable to probe for the
 * existence of the LCD so it must be told at load time whether it should
 * be enabled or not.
 *
 * Todo:
 * - testing with 4x4
 * - testing with interrupt hw
 *
 * General notes:
 * - User must set tuhold. It's in microseconds. According to the 108 spec,
 *   the hold time is supposed to be at least 1 microsecond.
 * - User must set num_cols=x num_rows=y, eg: x=2 means 128
 * - User must set arcfb_enable=1 to enable it
 * - User must set dio_addr=0xIOADDR cio_addr=0xIOADDR
 *
 */

#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/vmalloc.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/fb.h>
#include <linux/init.h>
#include <linux/arcfb.h>
#include <linux/platform_device.h>

#include <linux/uaccess.h>

#define floor8(a) (a&(~0x07))
#define floorXres(a,xres) (a&(~(xres - 1)))
#define iceil8(a) (((int)((a+7)/8))*8)
#define ceil64(a) (a|0x3F)
#define ceilXres(a,xres) (a|(xres - 1))

/* ks108 chipset specific defines and code */

#define KS_SET_DPY_START_LINE 	0xC0
#define KS_SET_PAGE_NUM 	0xB8
#define KS_SET_X 		0x40
#define KS_CEHI 		0x01
#define KS_CELO 		0x00
#define KS_SEL_CMD 		0x08
#define KS_SEL_DATA 		0x00
#define KS_DPY_ON 		0x3F
#define KS_DPY_OFF 		0x3E
#define KS_INTACK 		0x40
#define KS_CLRINT		0x02

struct arcfb_par {
	unsigned long dio_addr;
	unsigned long cio_addr;
	unsigned long c2io_addr;
	atomic_t ref_count;
	unsigned char cslut[9];
	struct fb_info *info;
	unsigned int irq;
	spinlock_t lock;
};

static struct fb_fix_screeninfo arcfb_fix __initdata = {
	.id =		"arcfb",
	.type =		FB_TYPE_PACKED_PIXELS,
	.visual =	FB_VISUAL_MONO01,
	.xpanstep =	0,
	.ypanstep =	1,
	.ywrapstep =	0,
	.accel =	FB_ACCEL_NONE,
};

static struct fb_var_screeninfo arcfb_var __initdata = {
	.xres		= 128,
	.yres		= 64,
	.xres_virtual	= 128,
	.yres_virtual	= 64,
	.bits_per_pixel	= 1,
	.nonstd		= 1,
};

static unsigned long num_cols;
static unsigned long num_rows;
static unsigned long dio_addr;
static unsigned long cio_addr;
static unsigned long c2io_addr;
static unsigned long splashval;
static unsigned long tuhold;
static unsigned int nosplash;
static unsigned int arcfb_enable;
static unsigned int irq;

static DECLARE_WAIT_QUEUE_HEAD(arcfb_waitq);

static void ks108_writeb_ctl(struct arcfb_par *par,
				unsigned int chipindex, unsigned char value)
{
	unsigned char chipselval = par->cslut[chipindex];

	outb(chipselval|KS_CEHI|KS_SEL_CMD, par->cio_addr);
	outb(value, par->dio_addr);
	udelay(tuhold);
	outb(chipselval|KS_CELO|KS_SEL_CMD, par->cio_addr);
}

static void ks108_writeb_mainctl(struct arcfb_par *par, unsigned char value)
{

	outb(value, par->cio_addr);
	udelay(tuhold);
}

static unsigned char ks108_readb_ctl2(struct arcfb_par *par)
{
	return inb(par->c2io_addr);
}

static void ks108_writeb_data(struct arcfb_par *par,
				unsigned int chipindex, unsigned char value)
{
	unsigned char chipselval = par->cslut[chipindex];

	outb(chipselval|KS_CEHI|KS_SEL_DATA, par->cio_addr);
	outb(value, par->dio_addr);
	udelay(tuhold);
	outb(chipselval|KS_CELO|KS_SEL_DATA, par->cio_addr);
}

static void ks108_set_start_line(struct arcfb_par *par,
				unsigned int chipindex, unsigned char y)
{
	ks108_writeb_ctl(par, chipindex, KS_SET_DPY_START_LINE|y);
}

static void ks108_set_yaddr(struct arcfb_par *par,
				unsigned int chipindex, unsigned char y)
{
	ks108_writeb_ctl(par, chipindex, KS_SET_PAGE_NUM|y);
}

static void ks108_set_xaddr(struct arcfb_par *par,
				unsigned int chipindex, unsigned char x)
{
	ks108_writeb_ctl(par, chipindex, KS_SET_X|x);
}

static void ks108_clear_lcd(struct arcfb_par *par, unsigned int chipindex)
{
	int i,j;

	for (i = 0; i <= 8; i++) {
		ks108_set_yaddr(par, chipindex, i);
		ks108_set_xaddr(par, chipindex, 0);
		for (j = 0; j < 64; j++) {
			ks108_writeb_data(par, chipindex,
				(unsigned char) splashval);
		}
	}
}

/* main arcfb functions */

static int arcfb_open(struct fb_info *info, int user)
{
	struct arcfb_par *par = info->par;

	atomic_inc(&par->ref_count);
	return 0;
}

static int arcfb_release(struct fb_info *info, int user)
{
	struct arcfb_par *par = info->par;
	int count = atomic_read(&par->ref_count);

	if (!count)
		return -EINVAL;
	atomic_dec(&par->ref_count);
	return 0;
}

static int arcfb_pan_display(struct fb_var_screeninfo *var,
				struct fb_info *info)
{
	int i;
	struct arcfb_par *par = info->par;

	if ((var->vmode & FB_VMODE_YWRAP) && (var->yoffset < 64)
		&& (info->var.yres <= 64)) {
		for (i = 0; i < num_cols; i++) {
			ks108_set_start_line(par, i, var->yoffset);
		}
		info->var.yoffset = var->yoffset;
		return 0;
	}

	return -EINVAL;
}

static irqreturn_t arcfb_interrupt(int vec, void *dev_instance)
{
	struct fb_info *info = dev_instance;
	unsigned char ctl2status;
	struct arcfb_par *par = info->par;

	ctl2status = ks108_readb_ctl2(par);

	if (!(ctl2status & KS_INTACK)) /* not arc generated interrupt */
		return IRQ_NONE;

	ks108_writeb_mainctl(par, KS_CLRINT);

	spin_lock(&par->lock);
        if (waitqueue_active(&arcfb_waitq)) {
                wake_up(&arcfb_waitq);
        }
	spin_unlock(&par->lock);

	return IRQ_HANDLED;
}

/*
 * here we handle a specific page on the lcd. the complexity comes from
 * the fact that the fb is laidout in 8xX vertical columns. we extract
 * each write of 8 vertical pixels. then we shift out as we move along
 * X. That's what rightshift does. bitmask selects the desired input bit.
 */
static void arcfb_lcd_update_page(struct arcfb_par *par, unsigned int upper,
		unsigned int left, unsigned int right, unsigned int distance)
{
	unsigned char *src;
	unsigned int xindex, yindex, chipindex, linesize;
	int i;
	unsigned char val;
	unsigned char bitmask, rightshift;

	xindex = left >> 6;
	yindex = upper >> 6;
	chipindex = (xindex + (yindex*num_cols));

	ks108_set_yaddr(par, chipindex, upper/8);

	linesize = par->info->var.xres/8;
	src = (unsigned char __force *) par->info->screen_base + (left/8) +
		(upper * linesize);
	ks108_set_xaddr(par, chipindex, left);

	bitmask=1;
	rightshift=0;
	while (left <= right) {
		val = 0;
		for (i = 0; i < 8; i++) {
			if ( i > rightshift) {
				val |= (*(src + (i*linesize)) & bitmask)
						<< (i - rightshift);
			} else {
				val |= (*(src + (i*linesize)) & bitmask)
						 >> (rightshift - i);
			}
		}
		ks108_writeb_data(par, chipindex, val);
		left++;
		if (bitmask == 0x80) {
			bitmask = 1;
			src++;
			rightshift=0;
		} else {
			bitmask <<= 1;
			rightshift++;
		}
	}
}

/*
 * here we handle the entire vertical page of the update. we write across
 * lcd chips. update_page uses the upper/left values to decide which
 * chip to select for the right. upper is needed for setting the page
 * desired for the write.
 */
static void arcfb_lcd_update_vert(struct arcfb_par *par, unsigned int top,
		unsigned int bottom, unsigned int left, unsigned int right)
{
	unsigned int distance, upper, lower;

	distance = (bottom - top) + 1;
	upper = top;
	lower = top + 7;

	while (distance > 0) {
		distance -= 8;
		arcfb_lcd_update_page(par, upper, left, right, 8);
		upper = lower + 1;
		lower = upper + 7;
	}
}

/*
 * here we handle horizontal blocks for the update. update_vert will
 * handle spaning multiple pages. we break out each horizontal
 * block in to individual blocks no taller than 64 pixels.
 */
static void arcfb_lcd_update_horiz(struct arcfb_par *par, unsigned int left,
			unsigned int right, unsigned int top, unsigned int h)
{
	unsigned int distance, upper, lower;

	distance = h;
	upper = floor8(top);
	lower = min(upper + distance - 1, ceil64(upper));

	while (distance > 0) {
		distance -= ((lower - upper) + 1 );
		arcfb_lcd_update_vert(par, upper, lower, left, right);
		upper = lower + 1;
		lower = min(upper + distance - 1, ceil64(upper));