/* sunxvr1000.c: Sun XVR-1000 fb driver for sparc64 systems
 *
 * License: GPL
 *
 * Copyright (C) 2010 David S. Miller (davem@davemloft.net)
 */

#include <linux/kernel.h>
#include <linux/fb.h>
#include <linux/init.h>
#include <linux/of.h>
#include <linux/platform_device.h>

struct gfb_info {
        struct fb_info          *info;

        char __iomem            *fb_base;
        unsigned long           fb_base_phys;

        struct device_node      *of_node;

        unsigned int            width;
        unsigned int            height;
        unsigned int            depth;
        unsigned int            fb_size;

        u32                     pseudo_palette[16];
};

static int gfb_get_props(struct gfb_info *gp)
{
        gp->width = of_getintprop_default(gp->of_node, "width", 0);
        gp->height = of_getintprop_default(gp->of_node, "height", 0);
        gp->depth = of_getintprop_default(gp->of_node, "depth", 32);

        if (!gp->width || !gp->height) {
                printk(KERN_ERR "gfb: Critical properties missing for %pOF\n",
                       gp->of_node);
                return -EINVAL;
        }

        return 0;
}

static int gfb_setcolreg(unsigned regno,
                         unsigned red, unsigned green, unsigned blue,
                         unsigned transp, struct fb_info *info)
{
        u32 value;

        if (regno < 16) {
                red >>= 8;
                green >>= 8;
                blue >>= 8;

                value = (blue << 16) | (green << 8) | red;
                ((u32 *)info->pseudo_palette)[regno] = value;
        }

        return 0;
}

static const struct fb_ops gfb_ops = {
        .owner                  = THIS_MODULE,
        FB_DEFAULT_IOMEM_OPS,
        .fb_setcolreg           = gfb_setcolreg,
};

static int gfb_set_fbinfo(struct gfb_info *gp)
{
        struct fb_info *info = gp->info;
        struct fb_var_screeninfo *var = &info->var;

        info->fbops = &gfb_ops;
        info->screen_base = gp->fb_base;
        info->screen_size = gp->fb_size;

        info->pseudo_palette = gp->pseudo_palette;

        /* Fill fix common fields */
        strscpy(info->fix.id, "gfb", sizeof(info->fix.id));
        info->fix.smem_start = gp->fb_base_phys;
        info->fix.smem_len = gp->fb_size;
        info->fix.type = FB_TYPE_PACKED_PIXELS;
        if (gp->depth == 32 || gp->depth == 24)
                info->fix.visual = FB_VISUAL_TRUECOLOR;
        else
                info->fix.visual = FB_VISUAL_PSEUDOCOLOR;

        var->xres = gp->width;
        var->yres = gp->height;
        var->xres_virtual = var->xres;
        var->yres_virtual = var->yres;
        var->bits_per_pixel = gp->depth;

        var->red.offset = 0;
        var->red.length = 8;
        var->green.offset = 8;
        var->green.length = 8;
        var->blue.offset = 16;
        var->blue.length = 8;
        var->transp.offset = 0;
        var->transp.length = 0;

        if (fb_alloc_cmap(&info->cmap, 256, 0)) {
                printk(KERN_ERR "gfb: Cannot allocate color map.\n");
                return -ENOMEM;
        }

        return 0;
}

static int gfb_probe(struct platform_device *op)
{
        struct device_node *dp = op->dev.of_node;
        struct fb_info *info;
        struct gfb_info *gp;
        int err;

        info = framebuffer_alloc(sizeof(struct gfb_info), &op->dev);
        if (!info) {
                err = -ENOMEM;
                goto err_out;
        }

        gp = info->par;
        gp->info = info;
        gp->of_node = dp;

        gp->fb_base_phys = op->resource[6].start;

        err = gfb_get_props(gp);
        if (err)
                goto err_release_fb;

        /* Framebuffer length is the same regardless of resolution. */
        info->fix.line_length = 16384;
        gp->fb_size = info->fix.line_length * gp->height;

        gp->fb_base = of_ioremap(&op->resource[6], 0,
                                 gp->fb_size, "gfb fb");
        if (!gp->fb_base) {
                err = -ENOMEM;
                goto err_release_fb;
        }

        err = gfb_set_fbinfo(gp);
        if (err)
                goto err_unmap_fb;

        printk("gfb: Found device at %pOF\n", dp);

        err = register_framebuffer(info);
        if (err < 0) {
                printk(KERN_ERR "gfb: Could not register framebuffer %pOF\n",
                       dp);
                goto err_unmap_fb;
        }

        dev_set_drvdata(&op->dev, info);

        return 0;

err_unmap_fb:
        of_iounmap(&op->resource[6], gp->fb_base, gp->fb_size);

err_release_fb:
        framebuffer_release(info);

err_out:
        return err;
}

static const struct of_device_id gfb_match[] = {
        {
                .name = "SUNW,gfb",
        },
        {},
};

static struct platform_driver gfb_driver = {
        .probe          = gfb_probe,
        .driver = {
                .name                   = "gfb",
                .of_match_table         = gfb_match,
                .suppress_bind_attrs    = true,
        },
};

static int __init gfb_init(void)
{
        if (fb_get_options("gfb", NULL))
                return -ENODEV;

        return platform_driver_register(&gfb_driver);
}
device_initcall(gfb_init);