/*
 * broadsheetfb.c -- FB driver for E-Ink Broadsheet controller
 *
 * Copyright (C) 2008, Jaya Kumar
 *
 * 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 is written to be used with the Broadsheet display controller.
 *
 * It is intended to be architecture independent. A board specific driver
 * must be used to perform all the physical IO interactions.
 *
 */

#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/platform_device.h>
#include <linux/list.h>
#include <linux/uaccess.h>

#include <video/broadsheetfb.h>

/* Display specific information */
#define DPY_W 800
#define DPY_H 600

static struct fb_fix_screeninfo broadsheetfb_fix __devinitdata = {
        .id =           "broadsheetfb",
        .type =         FB_TYPE_PACKED_PIXELS,
        .visual =       FB_VISUAL_STATIC_PSEUDOCOLOR,
        .xpanstep =     0,
        .ypanstep =     0,
        .ywrapstep =    0,
        .line_length =  DPY_W,
        .accel =        FB_ACCEL_NONE,
};

static struct fb_var_screeninfo broadsheetfb_var __devinitdata = {
        .xres           = DPY_W,
        .yres           = DPY_H,
        .xres_virtual   = DPY_W,
        .yres_virtual   = DPY_H,
        .bits_per_pixel = 8,
        .grayscale      = 1,
        .red =          { 0, 4, 0 },
        .green =        { 0, 4, 0 },
        .blue =         { 0, 4, 0 },
        .transp =       { 0, 0, 0 },
};

/* main broadsheetfb functions */
static void broadsheet_issue_data(struct broadsheetfb_par *par, u16 data)
{
        par->board->set_ctl(par, BS_WR, 0);
        par->board->set_hdb(par, data);
        par->board->set_ctl(par, BS_WR, 1);
}

static void broadsheet_issue_cmd(struct broadsheetfb_par *par, u16 data)
{
        par->board->set_ctl(par, BS_DC, 0);
        broadsheet_issue_data(par, data);
}

static void broadsheet_send_command(struct broadsheetfb_par *par, u16 data)
{
        par->board->wait_for_rdy(par);

        par->board->set_ctl(par, BS_CS, 0);
        broadsheet_issue_cmd(par, data);
        par->board->set_ctl(par, BS_DC, 1);
        par->board->set_ctl(par, BS_CS, 1);
}

static void broadsheet_send_cmdargs(struct broadsheetfb_par *par, u16 cmd,
                                        int argc, u16 *argv)
{
        int i;

        par->board->wait_for_rdy(par);

        par->board->set_ctl(par, BS_CS, 0);
        broadsheet_issue_cmd(par, cmd);
        par->board->set_ctl(par, BS_DC, 1);

        for (i = 0; i < argc; i++)
                broadsheet_issue_data(par, argv[i]);
        par->board->set_ctl(par, BS_CS, 1);
}

static void broadsheet_burst_write(struct broadsheetfb_par *par, int size,
                                        u16 *data)
{
        int i;
        u16 tmp;

        par->board->set_ctl(par, BS_CS, 0);
        par->board->set_ctl(par, BS_DC, 1);

        for (i = 0; i < size; i++) {
                par->board->set_ctl(par, BS_WR, 0);
                tmp = (data[i] & 0x0F) << 4;
                tmp |= (data[i] & 0x0F00) << 4;
                par->board->set_hdb(par, tmp);
                par->board->set_ctl(par, BS_WR, 1);
        }

        par->board->set_ctl(par, BS_CS, 1);
}

static u16 broadsheet_get_data(struct broadsheetfb_par *par)
{
        u16 res;
        /* wait for ready to go hi. (lo is busy) */
        par->board->wait_for_rdy(par);

        /* cs lo, dc lo for cmd, we lo for each data, db as usual */
        par->board->set_ctl(par, BS_DC, 1);
        par->board->set_ctl(par, BS_CS, 0);
        par->board->set_ctl(par, BS_WR, 0);

        res = par->board->get_hdb(par);

        /* strobe wr */
        par->board->set_ctl(par, BS_WR, 1);
        par->board->set_ctl(par, BS_CS, 1);

        return res;
}

static void broadsheet_write_reg(struct broadsheetfb_par *par, u16 reg,
                                        u16 data)
{
        /* wait for ready to go hi. (lo is busy) */
        par->board->wait_for_rdy(par);

        /* cs lo, dc lo for cmd, we lo for each data, db as usual */
        par->board->set_ctl(par, BS_CS, 0);

        broadsheet_issue_cmd(par, BS_CMD_WR_REG);

        par->board->set_ctl(par, BS_DC, 1);

        broadsheet_issue_data(par, reg);
        broadsheet_issue_data(par, data);

        par->board->set_ctl(par, BS_CS, 1);
}

static u16 broadsheet_read_reg(struct broadsheetfb_par *par, u16 reg)
{
        broadsheet_send_command(par, reg);
        msleep(100);
        return broadsheet_get_data(par);
}

static void __devinit broadsheet_init_display(struct broadsheetfb_par *par)
{
        u16 args[5];

        args[0] = DPY_W;
        args[1] = DPY_H;
        args[2] = (100 | (1 << 8) | (1 << 9)); /* sdcfg */
        args[3] = 2; /* gdrv cfg */
        args[4] = (4 | (1 << 7)); /* lut index format */
        broadsheet_send_cmdargs(par, BS_CMD_INIT_DSPE_CFG, 5, args);

        /* did the controller really set it? */
        broadsheet_send_cmdargs(par, BS_CMD_INIT_DSPE_CFG, 5, args);

        args[0] = 4; /* fsync len */
        args[1] = (10 << 8) | 4; /* fend/fbegin len */
        args[2] = 10; /* line sync len */
        args[3] = (100 << 8) | 4; /* line end/begin len */
        args[4] = 6; /* pixel clock cfg */
        broadsheet_send_cmdargs(par, BS_CMD_INIT_DSPE_TMG, 5, args);

        /* setup waveform */
        args[0] = 0x886;
        args[1] = 0;
        broadsheet_send_cmdargs(par, BS_CMD_RD_WFM_INFO, 2, args);

        broadsheet_send_command(par, BS_CMD_UPD_GDRV_CLR);

        broadsheet_send_command(par, BS_CMD_WAIT_DSPE_TRG);

        broadsheet_write_reg(par, 0x330, 0x84);

        broadsheet_send_command(par, BS_CMD_WAIT_DSPE_TRG);

        args[0] = (0x3 << 4);
        broadsheet_send_cmdargs(par, BS_CMD_LD_IMG, 1, args);

        args[0] = 0x154;
        broadsheet_send_cmdargs(par, BS_CMD_WR_REG, 1, args);

        broadsheet_burst_write(par, DPY_W*DPY_H/2,
                                (u16 *) par->info->screen_base);

        broadsheet_send_command(par, BS_CMD_LD_IMG_END);

        args[0] = 0x4300;
        broadsheet_send_cmdargs(par, BS_CMD_UPD_FULL, 1, args);

        broadsheet_send_command(par, BS_CMD_WAIT_DSPE_TRG);

        broadsheet_send_command(par, BS_CMD_WAIT_DSPE_FREND);

        par->board->wait_for_rdy(par);
}

static void __devinit broadsheet_init(struct broadsheetfb_par *par)
{
        broadsheet_send_command(par, BS_CMD_INIT_SYS_RUN);
        /* the controller needs a second */
        msleep(1000);
        broadsheet_init_display(par);
}

static void broadsheetfb_dpy_update_pages(struct broadsheetfb_par *par,
                                                u16 y1, u16 y2)
{
        u16 args[5];
        unsigned char *buf = (unsigned char *)par->info->screen_base;

        /* y1 must be a multiple of 4 so drop the lower bits */
        y1 &= 0xFFFC;
        /* y2 must be a multiple of 4 , but - 1 so up the lower bits */
        y2 |= 0x0003;

        args[0] = 0x3 << 4;
        args[1] = 0;
        args[2] = y1;
        args[3] = cpu_to_le16(par->info->var.xres);
        args[4] = y2;
        broadsheet_send_cmdargs(par, BS_CMD_LD_IMG_AREA, 5, args);

        args[0] = 0x154;
        broadsheet_send_cmdargs(par, BS_CMD_WR_REG, 1, args);

        buf += y1 * par->info->var.xres;
        broadsheet_burst_write(par, ((1 + y2 - y1) * par->info->var.xres)/2,
                                (u16 *) buf);

        broadsheet_send_command(par, BS_CMD_LD_IMG_END);

        args[0] = 0x4300;
        broadsheet_send_cmdargs(par, BS_CMD_UPD_FULL, 1, args);

        broadsheet_send_command(par, BS_CMD_WAIT_DSPE_TRG);

        broadsheet_send_command(par, BS_CMD_WAIT_DSPE_FREND);

        par->board->wait_for_rdy(par);

}

static void broadsheetfb_dpy_update(struct broadsheetfb_par *par)
{
        u16 args[5];

        args[0] = 0x3 << 4;
        broadsheet_send_cmdargs(par, BS_CMD_LD_IMG, 1, args);

        args[0] = 0x154;
        broadsheet_send_cmdargs(par, BS_CMD_WR_REG, 1, args);
        broadsheet_burst_write(par, DPY_W*DPY_H/2,
                                (u16 *) par->info->screen_base);

        broadsheet_send_command(par, BS_CMD_LD_IMG_END);

        args[0] = 0x4300;
        broadsheet_send_cmdargs(par, BS_CMD_UPD_FULL, 1, args);

        broadsheet_send_command(par, BS_CMD_WAIT_DSPE_TRG);

        broadsheet_send_command(par, BS_CMD_WAIT_DSPE_FREND);

        par->board->wait_for_rdy(par);

}

/* this is called back from the deferred io workqueue */
static void broadsheetfb_dpy_deferred_io(struct fb_info *info,
                                struct list_head *pagelist)
{
        u16 y1 = 0, h = 0;
        int prev_index = -1;
        struct page *cur;
        struct fb_deferred_io *fbdefio = info->fbdefio;
        int h_inc;
        u16 yres = info->var.yres;
        u16 xres = info->var.xres;

        /* height increment is fixed per page */
        h_inc = DIV_ROUND_UP(PAGE_SIZE , xres);

        /* walk the written page list and swizzle the data */
        list_for_each_entry(cur, &fbdefio->pagelist, lru) {
                if (prev_index < 0) {
                        /* just starting so assign first page */
                        y1 = (cur->index << PAGE_SHIFT) / xres;
                        h = h_inc;
                } else if ((prev_index + 1) == cur->index) {
                        /* this page is consecutive so increase our height */
                        h += h_inc;
                } else {
                        /* page not consecutive, issue previous update first */
                        broadsheetfb_dpy_update_pages(info->par, y1, y1 + h);
                        /* start over with our non consecutive page */
                        y1 = (cur->index << PAGE_SHIFT) / xres;
                        h = h_inc;
                }
                prev_index = cur->index;
        }

        /* if we still have any pages to update we do so now */
        if (h >= yres) {
                /* its a full screen update, just do it */
                broadsheetfb_dpy_update(info->par);
        } else {
                broadsheetfb_dpy_update_pages(info->par, y1,
                                                min((u16) (y1 + h), yres));
        }
}

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

        sys_fillrect(info, rect);

        broadsheetfb_dpy_update(par);
}

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

        sys_copyarea(info, area);

        broadsheetfb_dpy_update(par);
}

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

        sys_imageblit(info, image);

        broadsheetfb_dpy_update(par);
}

/*
 * this is the slow path from userspace. they can seek and write to
 * the fb. it's inefficient to do anything less than a full screen draw
 */
static ssize_t broadsheetfb_write(struct fb_info *info, const char __user *buf,
                                size_t count, loff_t *ppos)
{
        struct broadsheetfb_par *par = info->par;
        unsigned long p = *ppos;
        void *dst;
        int err = 0;
        unsigned long total_size;

        if (info->state != FBINFO_STATE_RUNNING)
                return -EPERM;

        total_size = info->fix.smem_len;

        if (p > total_size)
                return -EFBIG;

        if (count > total_size) {
                err = -EFBIG;
                count = total_size;
        }

        if (count + p > total_size) {
                if (!err)
                        err = -ENOSPC;

                count = total_size - p;
        }

        dst = (void *)(info->screen_base + p);

        if (copy_from_user(dst, buf, count))
                err = -EFAULT;

        if  (!err)
                *ppos += count;

        broadsheetfb_dpy_update(par);

        return (err) ? err : count;
}

static struct fb_ops broadsheetfb_ops = {
        .owner          = THIS_MODULE,
        .fb_read        = fb_sys_read,
        .fb_write       = broadsheetfb_write,
        .fb_fillrect    = broadsheetfb_fillrect,
        .fb_copyarea    = broadsheetfb_copyarea,
        .fb_imageblit   = broadsheetfb_imageblit,
};

static struct fb_deferred_io broadsheetfb_defio = {
        .delay          = HZ/4,
        .deferred_io    = broadsheetfb_dpy_deferred_io,
};

static int __devinit broadsheetfb_probe(struct platform_device *dev)
{
        struct fb_info *info;
        struct broadsheet_board *board;
        int retval = -ENOMEM;
        int videomemorysize;
        unsigned char *videomemory;
        struct broadsheetfb_par *par;
        int i;

        /* pick up board specific routines */
        board = dev->dev.platform_data;
        if (!board)
                return -EINVAL;

        /* try to count device specific driver, if can't, platform recalls */
        if (!try_module_get(board->owner))
                return -ENODEV;

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

        videomemorysize = (DPY_W*DPY_H);
        videomemory = vmalloc(videomemorysize);
        if (!videomemory)
                goto err_fb_rel;

        memset(videomemory, 0, videomemorysize);

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

        info->var = broadsheetfb_var;
        info->fix = broadsheetfb_fix;
        info->fix.smem_len = videomemorysize;
        par = info->par;
        par->info = info;
        par->board = board;
        par->write_reg = broadsheet_write_reg;
        par->read_reg = broadsheet_read_reg;
        init_waitqueue_head(&par->waitq);

        info->flags = FBINFO_FLAG_DEFAULT;

        info->fbdefio = &broadsheetfb_defio;
        fb_deferred_io_init(info);

        retval = fb_alloc_cmap(&info->cmap, 16, 0);
        if (retval < 0) {
                dev_err(&dev->dev, "Failed to allocate colormap\n");
                goto err_vfree;
        }

        /* set cmap */
        for (i = 0; i < 16; i++)
                info->cmap.red[i] = (((2*i)+1)*(0xFFFF))/32;
        memcpy(info->cmap.green, info->cmap.red, sizeof(u16)*16);
        memcpy(info->cmap.blue, info->cmap.red, sizeof(u16)*16);

        retval = par->board->setup_irq(info);
        if (retval < 0)
                goto err_cmap;

        /* this inits the dpy */
        retval = board->init(par);
        if (retval < 0)
                goto err_free_irq;

        broadsheet_init(par);

        retval = register_framebuffer(info);
        if (retval < 0)
                goto err_free_irq;
        platform_set_drvdata(dev, info);

        printk(KERN_INFO
               "fb%d: Broadsheet frame buffer, using %dK of video memory\n",
               info->node, videomemorysize >> 10);


        return 0;

err_free_irq:
        board->cleanup(par);
err_cmap:
        fb_dealloc_cmap(&info->cmap);
err_vfree:
        vfree(videomemory);
err_fb_rel:
        framebuffer_release(info);
err:
        module_put(board->owner);
        return retval;

}

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

        if (info) {
                struct broadsheetfb_par *par = info->par;
                unregister_framebuffer(info);
                fb_deferred_io_cleanup(info);
                par->board->cleanup(par);
                fb_dealloc_cmap(&info->cmap);
                vfree((void *)info->screen_base);
                module_put(par->board->owner);
                framebuffer_release(info);
        }
        return 0;
}

static struct platform_driver broadsheetfb_driver = {
        .probe  = broadsheetfb_probe,
        .remove = broadsheetfb_remove,
        .driver = {
                .owner  = THIS_MODULE,
                .name   = "broadsheetfb",
        },
};

static int __init broadsheetfb_init(void)
{
        return platform_driver_register(&broadsheetfb_driver);
}

static void __exit broadsheetfb_exit(void)
{
        platform_driver_unregister(&broadsheetfb_driver);
}

module_init(broadsheetfb_init);
module_exit(broadsheetfb_exit);

MODULE_DESCRIPTION("fbdev driver for Broadsheet controller");
MODULE_AUTHOR("Jaya Kumar");
MODULE_LICENSE("GPL");