arcfb.c

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/*
 * linux/drivers/video/arcfb.c -- FB driver for Arc monochrome LCD board
 *
 * Copyright (C) 2005, Jaya Kumar <[email protected]>
 *
 * 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/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 __devinitdata = {
    .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 __devinitdata = {
    .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));
    }
}

/*
 * here we start the process of splitting out the fb update into
 * individual blocks of pixels. we end up splitting into 64x64 blocks
 * and finally down to 64x8 pages.
 */
static void arcfb_lcd_update(struct arcfb_par *par, unsigned int dx,
            unsigned int dy, unsigned int w, unsigned int h)
{
    unsigned int left, right, distance, y;

    /* align the request first */
    y = floor8(dy);
    h += dy - y;
    h = iceil8(h);

    distance = w;
    left = dx;
    right = min(left + w - 1, ceil64(left));

    while (distance > 0) {
        arcfb_lcd_update_horiz(par, left, right, y, h);
        distance -= ((right - left) + 1);
        left = right + 1;
        right = min(left + distance - 1, ceil64(left));
    }
}

static void arcfb_fillrect(struct fb_info *info,
               const struct fb_fillrect *rect)
{
    struct arcfb_par *par = info->par;

    sys_fillrect(info, rect);

    /* update the physical lcd */
    arcfb_lcd_update(par, rect->dx, rect->dy, rect->width, rect->height);
}

static void arcfb_copyarea(struct fb_info *info,
               const struct fb_copyarea *area)
{
    struct arcfb_par *par = info->par;

    sys_copyarea(info, area);

    /* update the physical lcd */
    arcfb_lcd_update(par, area->dx, area->dy, area->width, area->height);
}

static void arcfb_imageblit(struct fb_info *info, const struct fb_image *image)
{
    struct arcfb_par *par = info->par;

    sys_imageblit(info, image);

    /* update the physical lcd */
    arcfb_lcd_update(par, image->dx, image->dy, image->width,
                image->height);
}

static int arcfb_ioctl(struct fb_info *info,
              unsigned int cmd, unsigned long arg)
{
    void __user *argp = (void __user *)arg;
    struct arcfb_par *par = info->par;
    unsigned long flags;

    switch (cmd) {
        case FBIO_WAITEVENT:
        {
            DEFINE_WAIT(wait);
            /* illegal to wait on arc if no irq will occur */
            if (!par->irq)
                return -EINVAL;

            /* wait until the Arc has generated an interrupt
             * which will wake us up */
            spin_lock_irqsave(&par->lock, flags);
            prepare_to_wait(&arcfb_waitq, &wait,
                    TASK_INTERRUPTIBLE);
            spin_unlock_irqrestore(&par->lock, flags);
            schedule();
            finish_wait(&arcfb_waitq, &wait);
        }
        case FBIO_GETCONTROL2:
        {
            unsigned char ctl2;

            ctl2 = ks108_readb_ctl2(info->par);
            if (copy_to_user(argp, &ctl2, sizeof(ctl2)))
                return -EFAULT;
            return 0;
        }
        default:
            return -EINVAL;
    }
}

/*
 * this is the access path from userspace. they can seek and write to
 * the fb. it's inefficient for them to do anything less than 64*8
 * writes since we update the lcd in each write() anyway.
 */
static ssize_t arcfb_write(struct fb_info *info, const char __user *buf,
               size_t count, loff_t *ppos)
{
    /* modded from epson 1355 */

    unsigned long p;
    int err=-EINVAL;
    unsigned int fbmemlength,x,y,w,h, bitppos, startpos, endpos, bitcount;
    struct arcfb_par *par;
    unsigned int xres;

    p = *ppos;
    par = info->par;
    xres = info->var.xres;
    fbmemlength = (xres * info->var.yres)/8;

    if (p > fbmemlength)
        return -ENOSPC;

    err = 0;
    if ((count + p) > fbmemlength) {
        count = fbmemlength - p;
        err = -ENOSPC;
    }

    if (count) {
        char *base_addr;

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


    bitppos = p*8;
    startpos = floorXres(bitppos, xres);
    endpos = ceilXres((bitppos + (count*8)), xres);
    bitcount = endpos - startpos;

    x = startpos % xres;
    y = startpos / xres;
    w = xres;
    h = bitcount / xres;
    arcfb_lcd_update(par, x, y, w, h);

    if (count)
        return count;
    return err;
}

static struct fb_ops arcfb_ops = {
    .owner      = THIS_MODULE,
    .fb_open    = arcfb_open,
    .fb_read        = fb_sys_read,
    .fb_write   = arcfb_write,
    .fb_release = arcfb_release,
    .fb_pan_display = arcfb_pan_display,
    .fb_fillrect    = arcfb_fillrect,
    .fb_copyarea    = arcfb_copyarea,
    .fb_imageblit   = arcfb_imageblit,
    .fb_ioctl   = arcfb_ioctl,
};

static int __devinit arcfb_probe(struct platform_device *dev)
{
    struct fb_info *info;
    int retval = -ENOMEM;
    int videomemorysize;
    unsigned char *videomemory;
    struct arcfb_par *par;
    int i;

    videomemorysize = (((64*64)*num_cols)*num_rows)/8;

    /* We need a flat backing store for the Arc's
       less-flat actual paged framebuffer */
    videomemory = vzalloc(videomemorysize);
    if (!videomemory)
        return retval;

    info = framebuffer_alloc(sizeof(struct arcfb_par), &dev->dev);
    if (!info)
        goto err;

    info->screen_base = (char __iomem *)videomemory;
    info->fbops = &arcfb_ops;

    info->var = arcfb_var;
    info->fix = arcfb_fix;
    par = info->par;
    par->info = info;

    if (!dio_addr || !cio_addr || !c2io_addr) {
        printk(KERN_WARNING "no IO addresses supplied\n");
        goto err1;
    }
    par->dio_addr = dio_addr;
    par->cio_addr = cio_addr;
    par->c2io_addr = c2io_addr;
    par->cslut[0] = 0x00;
    par->cslut[1] = 0x06;
    info->flags = FBINFO_FLAG_DEFAULT;
    spin_lock_init(&par->lock);
    retval = register_framebuffer(info);
    if (retval < 0)
        goto err1;
    platform_set_drvdata(dev, info);
    if (irq) {
        par->irq = irq;
        if (request_irq(par->irq, &arcfb_interrupt, IRQF_SHARED,
                "arcfb", info)) {
            printk(KERN_INFO
                "arcfb: Failed req IRQ %d\n", par->irq);
            retval = -EBUSY;
            goto err1;
        }
    }
    printk(KERN_INFO
           "fb%d: Arc frame buffer device, using %dK of video memory\n",
           info->node, videomemorysize >> 10);

    /* this inits the lcd but doesn't clear dirty pixels */
    for (i = 0; i < num_cols * num_rows; i++) {
        ks108_writeb_ctl(par, i, KS_DPY_OFF);
        ks108_set_start_line(par, i, 0);
        ks108_set_yaddr(par, i, 0);
        ks108_set_xaddr(par, i, 0);
        ks108_writeb_ctl(par, i, KS_DPY_ON);
    }

    /* if we were told to splash the screen, we just clear it */
    if (!nosplash) {
        for (i = 0; i < num_cols * num_rows; i++) {
            printk(KERN_INFO "fb%d: splashing lcd %d\n",
                info->node, i);
            ks108_set_start_line(par, i, 0);
            ks108_clear_lcd(par, i);
        }
    }

    return 0;
err1:
    framebuffer_release(info);
err:
    vfree(videomemory);
    return retval;
}

static int __devexit arcfb_remove(struct platform_device *dev)
{
    struct fb_info *info = platform_get_drvdata(dev);

    if (info) {
        unregister_framebuffer(info);
        vfree((void __force *)info->screen_base);
        framebuffer_release(info);
    }
    return 0;
}

static struct platform_driver arcfb_driver = {
    .probe  = arcfb_probe,
    .remove = __devexit_p(arcfb_remove),
    .driver = {
        .name   = "arcfb",
    },
};

static struct platform_device *arcfb_device;

static int __init arcfb_init(void)
{
    int ret;

    if (!arcfb_enable)
        return -ENXIO;

    ret = platform_driver_register(&arcfb_driver);
    if (!ret) {
        arcfb_device = platform_device_alloc("arcfb", 0);
        if (arcfb_device) {
            ret = platform_device_add(arcfb_device);
        } else {
            ret = -ENOMEM;
        }
        if (ret) {
            platform_device_put(arcfb_device);
            platform_driver_unregister(&arcfb_driver);
        }
    }
    return ret;

}

static void __exit arcfb_exit(void)
{
    platform_device_unregister(arcfb_device);
    platform_driver_unregister(&arcfb_driver);
}

module_param(num_cols, ulong, 0);
MODULE_PARM_DESC(num_cols, "Num horiz panels, eg: 2 = 128 bit wide");
module_param(num_rows, ulong, 0);
MODULE_PARM_DESC(num_rows, "Num vert panels, eg: 1 = 64 bit high");
module_param(nosplash, uint, 0);
MODULE_PARM_DESC(nosplash, "Disable doing the splash screen");
module_param(arcfb_enable, uint, 0);
MODULE_PARM_DESC(arcfb_enable, "Enable communication with Arc board");
module_param(dio_addr, ulong, 0);
MODULE_PARM_DESC(dio_addr, "IO address for data, eg: 0x480");
module_param(cio_addr, ulong, 0);
MODULE_PARM_DESC(cio_addr, "IO address for control, eg: 0x400");
module_param(c2io_addr, ulong, 0);
MODULE_PARM_DESC(c2io_addr, "IO address for secondary control, eg: 0x408");
module_param(splashval, ulong, 0);
MODULE_PARM_DESC(splashval, "Splash pattern: 0xFF is black, 0x00 is green");
module_param(tuhold, ulong, 0);
MODULE_PARM_DESC(tuhold, "Time to hold between strobing data to Arc board");
module_param(irq, uint, 0);
MODULE_PARM_DESC(irq, "IRQ for the Arc board");

module_init(arcfb_init);
module_exit(arcfb_exit);

MODULE_DESCRIPTION("fbdev driver for Arc monochrome LCD board");
MODULE_AUTHOR("Jaya Kumar");
MODULE_LICENSE("GPL");