/*
 *      linux/drivers/video/pmagb-b-fb.c
 *
 *      PMAGB-B TURBOchannel Smart Frame Buffer (SFB) 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.
 *
 *      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
 *
 *      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/delay.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/pmagb-b-fb.h>


struct pmagbbfb_par {
        volatile void __iomem *mmio;
        volatile void __iomem *smem;
        volatile u32 __iomem *sfb;
        volatile u32 __iomem *dac;
        unsigned int osc0;
        unsigned int osc1;
        int slot;
};


static const struct fb_var_screeninfo pmagbbfb_defined = {
        .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,
        .sync           = FB_SYNC_ON_GREEN,
        .vmode          = FB_VMODE_NONINTERLACED,
};

static const struct fb_fix_screeninfo pmagbbfb_fix = {
        .id             = "PMAGB-BA",
        .smem_len       = (2048 * 1024),
        .type           = FB_TYPE_PACKED_PIXELS,
        .visual         = FB_VISUAL_PSEUDOCOLOR,
        .mmio_len       = PMAGB_B_FBMEM,
};


static inline void sfb_write(struct pmagbbfb_par *par, unsigned int reg, u32 v)
{
        writel(v, par->sfb + reg / 4);
}

static inline u32 sfb_read(struct pmagbbfb_par *par, unsigned int reg)
{
        return readl(par->sfb + reg / 4);
}

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

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

static inline void gp0_write(struct pmagbbfb_par *par, u32 v)
{
        writel(v, par->mmio + PMAGB_B_GP0);
}


/*
 * Set the palette.
 */
static int pmagbbfb_setcolreg(unsigned int regno, unsigned int red,
                              unsigned int green, unsigned int blue,
                              unsigned int transp, struct fb_info *info)
{
        struct pmagbbfb_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 pmagbbfb_ops = {
        .owner          = THIS_MODULE,
        FB_DEFAULT_IOMEM_OPS,
        .fb_setcolreg   = pmagbbfb_setcolreg,
};


/*
 * Turn the hardware cursor off.
 */
static void pmagbbfb_erase_cursor(struct fb_info *info)
{
        struct pmagbbfb_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);
}

/*
 * Set up screen parameters.
 */
static void pmagbbfb_screen_setup(struct fb_info *info)
{
        struct pmagbbfb_par *par = info->par;

        info->var.xres = ((sfb_read(par, SFB_REG_VID_HOR) >>
                           SFB_VID_HOR_PIX_SHIFT) & SFB_VID_HOR_PIX_MASK) * 4;
        info->var.xres_virtual = info->var.xres;
        info->var.yres = (sfb_read(par, SFB_REG_VID_VER) >>
                          SFB_VID_VER_SL_SHIFT) & SFB_VID_VER_SL_MASK;
        info->var.yres_virtual = info->var.yres;
        info->var.left_margin = ((sfb_read(par, SFB_REG_VID_HOR) >>
                                  SFB_VID_HOR_BP_SHIFT) &
                                 SFB_VID_HOR_BP_MASK) * 4;
        info->var.right_margin = ((sfb_read(par, SFB_REG_VID_HOR) >>
                                   SFB_VID_HOR_FP_SHIFT) &
                                  SFB_VID_HOR_FP_MASK) * 4;
        info->var.upper_margin = (sfb_read(par, SFB_REG_VID_VER) >>
                                  SFB_VID_VER_BP_SHIFT) & SFB_VID_VER_BP_MASK;
        info->var.lower_margin = (sfb_read(par, SFB_REG_VID_VER) >>
                                  SFB_VID_VER_FP_SHIFT) & SFB_VID_VER_FP_MASK;
        info->var.hsync_len = ((sfb_read(par, SFB_REG_VID_HOR) >>
                                SFB_VID_HOR_SYN_SHIFT) &
                               SFB_VID_HOR_SYN_MASK) * 4;
        info->var.vsync_len = (sfb_read(par, SFB_REG_VID_VER) >>
                               SFB_VID_VER_SYN_SHIFT) & SFB_VID_VER_SYN_MASK;

        info->fix.line_length = info->var.xres;
};

/*
 * Determine oscillator configuration.
 */
static void pmagbbfb_osc_setup(struct fb_info *info)
{
        static unsigned int pmagbbfb_freqs[] = {
                130808, 119843, 104000, 92980, 74370, 72800,
                69197, 66000, 65000, 50350, 36000, 32000, 25175
        };
        struct pmagbbfb_par *par = info->par;
        struct tc_bus *tbus = to_tc_dev(info->device)->bus;
        u32 count0 = 8, count1 = 8, counttc = 16 * 256 + 8;
        u32 freq0, freq1, freqtc = tc_get_speed(tbus) / 250;
        int i, j;

        gp0_write(par, 0);                              /* select Osc0 */
        for (j = 0; j < 16; j++) {
                mb();
                sfb_write(par, SFB_REG_TCCLK_COUNT, 0);
                mb();
                for (i = 0; i < 100; i++) {     /* nominally max. 20.5us */
                        if (sfb_read(par, SFB_REG_TCCLK_COUNT) == 0)
                                break;
                        udelay(1);
                }
                count0 += sfb_read(par, SFB_REG_VIDCLK_COUNT);
        }

        gp0_write(par, 1);                              /* select Osc1 */
        for (j = 0; j < 16; j++) {
                mb();
                sfb_write(par, SFB_REG_TCCLK_COUNT, 0);

                for (i = 0; i < 100; i++) {     /* nominally max. 20.5us */
                        if (sfb_read(par, SFB_REG_TCCLK_COUNT) == 0)
                                break;
                        udelay(1);
                }
                count1 += sfb_read(par, SFB_REG_VIDCLK_COUNT);
        }

        freq0 = (freqtc * count0 + counttc / 2) / counttc;
        par->osc0 = freq0;
        if (freq0 >= pmagbbfb_freqs[0] - (pmagbbfb_freqs[0] + 32) / 64 &&
            freq0 <= pmagbbfb_freqs[0] + (pmagbbfb_freqs[0] + 32) / 64)
                par->osc0 = pmagbbfb_freqs[0];

        freq1 = (par->osc0 * count1 + count0 / 2) / count0;
        par->osc1 = freq1;
        for (i = 0; i < ARRAY_SIZE(pmagbbfb_freqs); i++)
                if (freq1 >= pmagbbfb_freqs[i] -
                             (pmagbbfb_freqs[i] + 128) / 256 &&
                    freq1 <= pmagbbfb_freqs[i] +
                             (pmagbbfb_freqs[i] + 128) / 256) {
                        par->osc1 = pmagbbfb_freqs[i];
                        break;
                }

        if (par->osc0 - par->osc1 <= (par->osc0 + par->osc1 + 256) / 512 ||
            par->osc1 - par->osc0 <= (par->osc0 + par->osc1 + 256) / 512)
                par->osc1 = 0;

        gp0_write(par, par->osc1 != 0);                 /* reselect OscX */

        info->var.pixclock = par->osc1 ?
                             (1000000000 + par->osc1 / 2) / par->osc1 :
                             (1000000000 + par->osc0 / 2) / par->osc0;
};


static int pmagbbfb_probe(struct device *dev)
{
        struct tc_dev *tdev = to_tc_dev(dev);
        resource_size_t start, len;
        struct fb_info *info;
        struct pmagbbfb_par *par;
        char freq0[12], freq1[12];
        u32 vid_base;
        int err;

        info = framebuffer_alloc(sizeof(struct pmagbbfb_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 = &pmagbbfb_ops;
        info->fix = pmagbbfb_fix;
        info->var = pmagbbfb_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->sfb = par->mmio + PMAGB_B_SFB;
        par->dac = par->mmio + PMAGB_B_BT459;

        /* Frame buffer mapping setup.  */
        info->fix.smem_start = start + PMAGB_B_FBMEM;
        par->smem = ioremap(info->fix.smem_start, info->fix.smem_len);
        if (!par->smem) {
                printk(KERN_ERR "%s: Cannot map FB\n", dev_name(dev));
                err = -ENOMEM;
                goto err_mmio_map;
        }
        vid_base = sfb_read(par, SFB_REG_VID_BASE);
        info->screen_base = (void __iomem *)par->smem + vid_base * 0x1000;
        info->screen_size = info->fix.smem_len - 2 * vid_base * 0x1000;

        pmagbbfb_erase_cursor(info);
        pmagbbfb_screen_setup(info);
        pmagbbfb_osc_setup(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);

        snprintf(freq0, sizeof(freq0), "%u.%03uMHz",
                 par->osc0 / 1000, par->osc0 % 1000);
        snprintf(freq1, sizeof(freq1), "%u.%03uMHz",
                 par->osc1 / 1000, par->osc1 % 1000);

        fb_info(info, "%s frame buffer device at %s\n",
                info->fix.id, dev_name(dev));
        fb_info(info, "Osc0: %s, Osc1: %s, Osc%u selected\n",
                freq0, par->osc1 ? freq1 : "disabled", par->osc1 != 0);

        return 0;


err_smem_map:
        iounmap(par->smem);

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 pmagbbfb_remove(struct device *dev)
{
        struct tc_dev *tdev = to_tc_dev(dev);
        struct fb_info *info = dev_get_drvdata(dev);
        struct pmagbbfb_par *par = info->par;
        resource_size_t start, len;

        put_device(dev);
        unregister_framebuffer(info);
        iounmap(par->smem);
        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 pmagbbfb_tc_table[] = {
        { "DEC     ", "PMAGB-BA" },
        { }
};
MODULE_DEVICE_TABLE(tc, pmagbbfb_tc_table);

static struct tc_driver pmagbbfb_driver = {
        .id_table       = pmagbbfb_tc_table,
        .driver         = {
                .name   = "pmagbbfb",
                .bus    = &tc_bus_type,
                .probe  = pmagbbfb_probe,
                .remove = pmagbbfb_remove,
        },
};

static int __init pmagbbfb_init(void)
{
#ifndef MODULE
        if (fb_get_options("pmagbbfb", NULL))
                return -ENXIO;
#endif
        return tc_register_driver(&pmagbbfb_driver);
}

static void __exit pmagbbfb_exit(void)
{
        tc_unregister_driver(&pmagbbfb_driver);
}


module_init(pmagbbfb_init);
module_exit(pmagbbfb_exit);

MODULE_LICENSE("GPL");