/*
 *      linux/drivers/video/pmag-ba-fb.c
 *
 *      PMAG-BA TURBOchannel Color Frame Buffer (CFB) card support,
 *      derived from:
 *      "HP300 Topcat framebuffer support (derived from macfb of all things)
 *      Phil Blundell <philb@gnu.org> 1998", the original code can be
 *      found in the file hpfb.c in the same directory.
 *
 *      Based on digital document:
 *      "PMAG-BA TURBOchannel Color Frame Buffer
 *       Functional Specification", Revision 1.2, August 27, 1990
 *
 *      DECstation related code Copyright (C) 1999, 2000, 2001 by
 *      Michael Engel <engel@unix-ag.org>,
 *      Karsten Merker <merker@linuxtag.org> and
 *      Harald Koerfgen.
 *      Copyright (c) 2005, 2006  Maciej W. Rozycki
 *      Copyright (c) 2005  James Simmons
 *
 *      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/compiler.h>
#include <linux/errno.h>
#include <linux/fb.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/tc.h>
#include <linux/types.h>

#include <asm/io.h>

#include <video/pmag-ba-fb.h>


struct pmagbafb_par {
        volatile void __iomem *mmio;
        volatile u32 __iomem *dac;
};


static const struct fb_var_screeninfo pmagbafb_defined = {
        .xres           = 1024,
        .yres           = 864,
        .xres_virtual   = 1024,
        .yres_virtual   = 864,
        .bits_per_pixel = 8,
        .red.length     = 8,
        .green.length   = 8,
        .blue.length    = 8,
        .activate       = FB_ACTIVATE_NOW,
        .height         = -1,
        .width          = -1,
        .accel_flags    = FB_ACCEL_NONE,
        .pixclock       = 14452,
        .left_margin    = 116,
        .right_margin   = 12,
        .upper_margin   = 34,
        .lower_margin   = 0,
        .hsync_len      = 128,
        .vsync_len      = 3,
        .sync           = FB_SYNC_ON_GREEN,
        .vmode          = FB_VMODE_NONINTERLACED,
};

static const struct fb_fix_screeninfo pmagbafb_fix = {
        .id             = "PMAG-BA",
        .smem_len       = (1024 * 1024),
        .type           = FB_TYPE_PACKED_PIXELS,
        .visual         = FB_VISUAL_PSEUDOCOLOR,
        .line_length    = 1024,
        .mmio_len       = PMAG_BA_SIZE - PMAG_BA_BT459,
};


static inline void dac_write(struct pmagbafb_par *par, unsigned int reg, u8 v)
{
        writeb(v, par->dac + reg / 4);
}

static inline u8 dac_read(struct pmagbafb_par *par, unsigned int reg)
{
        return readb(par->dac + reg / 4);
}


/*
 * Set the palette.
 */
static int pmagbafb_setcolreg(unsigned int regno, unsigned int red,
                              unsigned int green, unsigned int blue,
                              unsigned int transp, struct fb_info *info)
{
        struct pmagbafb_par *par = info->par;

        if (regno >= info->cmap.len)
                return 1;

        red   >>= 8;    /* The cmap fields are 16 bits    */
        green >>= 8;    /* wide, but the hardware colormap */
        blue  >>= 8;    /* registers are only 8 bits wide */

        mb();
        dac_write(par, BT459_ADDR_LO, regno);
        dac_write(par, BT459_ADDR_HI, 0x00);
        wmb();
        dac_write(par, BT459_CMAP, red);
        wmb();
        dac_write(par, BT459_CMAP, green);
        wmb();
        dac_write(par, BT459_CMAP, blue);

        return 0;
}

static const struct fb_ops pmagbafb_ops = {
        .owner          = THIS_MODULE,
        FB_DEFAULT_IOMEM_OPS,
        .fb_setcolreg   = pmagbafb_setcolreg,
};


/*
 * Turn the hardware cursor off.
 */
static void pmagbafb_erase_cursor(struct fb_info *info)
{
        struct pmagbafb_par *par = info->par;

        mb();
        dac_write(par, BT459_ADDR_LO, 0x00);
        dac_write(par, BT459_ADDR_HI, 0x03);
        wmb();
        dac_write(par, BT459_DATA, 0x00);
}


static int pmagbafb_probe(struct device *dev)
{
        struct tc_dev *tdev = to_tc_dev(dev);
        resource_size_t start, len;
        struct fb_info *info;
        struct pmagbafb_par *par;
        int err;

        info = framebuffer_alloc(sizeof(struct pmagbafb_par), dev);
        if (!info)
                return -ENOMEM;

        par = info->par;
        dev_set_drvdata(dev, info);

        if (fb_alloc_cmap(&info->cmap, 256, 0) < 0) {
                printk(KERN_ERR "%s: Cannot allocate color map\n",
                       dev_name(dev));
                err = -ENOMEM;
                goto err_alloc;
        }

        info->fbops = &pmagbafb_ops;
        info->fix = pmagbafb_fix;
        info->var = pmagbafb_defined;

        /* Request the I/O MEM resource.  */
        start = tdev->resource.start;
        len = tdev->resource.end - start + 1;
        if (!request_mem_region(start, len, dev_name(dev))) {
                printk(KERN_ERR "%s: Cannot reserve FB region\n",
                       dev_name(dev));
                err = -EBUSY;
                goto err_cmap;
        }

        /* MMIO mapping setup.  */
        info->fix.mmio_start = start;
        par->mmio = ioremap(info->fix.mmio_start, info->fix.mmio_len);
        if (!par->mmio) {
                printk(KERN_ERR "%s: Cannot map MMIO\n", dev_name(dev));
                err = -ENOMEM;
                goto err_resource;
        }
        par->dac = par->mmio + PMAG_BA_BT459;

        /* Frame buffer mapping setup.  */
        info->fix.smem_start = start + PMAG_BA_FBMEM;
        info->screen_base = ioremap(info->fix.smem_start,
                                            info->fix.smem_len);
        if (!info->screen_base) {
                printk(KERN_ERR "%s: Cannot map FB\n", dev_name(dev));
                err = -ENOMEM;
                goto err_mmio_map;
        }
        info->screen_size = info->fix.smem_len;

        pmagbafb_erase_cursor(info);

        err = register_framebuffer(info);
        if (err < 0) {
                printk(KERN_ERR "%s: Cannot register framebuffer\n",
                       dev_name(dev));
                goto err_smem_map;
        }

        get_device(dev);

        fb_info(info, "%s frame buffer device at %s\n",
                info->fix.id, dev_name(dev));

        return 0;


err_smem_map:
        iounmap(info->screen_base);

err_mmio_map:
        iounmap(par->mmio);

err_resource:
        release_mem_region(start, len);

err_cmap:
        fb_dealloc_cmap(&info->cmap);

err_alloc:
        framebuffer_release(info);
        return err;
}

static int pmagbafb_remove(struct device *dev)
{
        struct tc_dev *tdev = to_tc_dev(dev);
        struct fb_info *info = dev_get_drvdata(dev);
        struct pmagbafb_par *par = info->par;
        resource_size_t start, len;

        put_device(dev);
        unregister_framebuffer(info);
        iounmap(info->screen_base);
        iounmap(par->mmio);
        start = tdev->resource.start;
        len = tdev->resource.end - start + 1;
        release_mem_region(start, len);
        fb_dealloc_cmap(&info->cmap);
        framebuffer_release(info);
        return 0;
}


/*
 * Initialize the framebuffer.
 */
static const struct tc_device_id pmagbafb_tc_table[] = {
        { "DEC     ", "PMAG-BA " },
        { }
};
MODULE_DEVICE_TABLE(tc, pmagbafb_tc_table);

static struct tc_driver pmagbafb_driver = {
        .id_table       = pmagbafb_tc_table,
        .driver         = {
                .name   = "pmagbafb",
                .bus    = &tc_bus_type,
                .probe  = pmagbafb_probe,
                .remove = pmagbafb_remove,
        },
};

static int __init pmagbafb_init(void)
{
#ifndef MODULE
        if (fb_get_options("pmagbafb", NULL))
                return -ENXIO;
#endif
        return tc_register_driver(&pmagbafb_driver);
}

static void __exit pmagbafb_exit(void)
{
        tc_unregister_driver(&pmagbafb_driver);
}


module_init(pmagbafb_init);
module_exit(pmagbafb_exit);

MODULE_LICENSE("GPL");