sm501fb.c

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/* linux/drivers/video/sm501fb.c
 *
 * Copyright (c) 2006 Simtec Electronics
 *  Vincent Sanders <[email protected]>
 *  Ben Dooks <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Framebuffer driver for the Silicon Motion SM501
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/tty.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/fb.h>
#include <linux/init.h>
#include <linux/vmalloc.h>
#include <linux/dma-mapping.h>
#include <linux/interrupt.h>
#include <linux/workqueue.h>
#include <linux/wait.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/console.h>
#include <linux/io.h>

#include <asm/uaccess.h>
#include <asm/div64.h>

#ifdef CONFIG_PM
#include <linux/pm.h>
#endif

#include <linux/sm501.h>
#include <linux/sm501-regs.h>

#include "edid.h"

static char *fb_mode = "640x480-16@60";
static unsigned long default_bpp = 16;

static struct fb_videomode __devinitdata sm501_default_mode = {
    .refresh    = 60,
    .xres       = 640,
    .yres       = 480,
    .pixclock   = 20833,
    .left_margin    = 142,
    .right_margin   = 13,
    .upper_margin   = 21,
    .lower_margin   = 1,
    .hsync_len  = 69,
    .vsync_len  = 3,
    .sync       = FB_SYNC_HOR_HIGH_ACT | FB_SYNC_VERT_HIGH_ACT,
    .vmode      = FB_VMODE_NONINTERLACED
};

#define NR_PALETTE  256

enum sm501_controller {
    HEAD_CRT    = 0,
    HEAD_PANEL  = 1,
};

/* SM501 memory address.
 *
 * This structure is used to track memory usage within the SM501 framebuffer
 * allocation. The sm_addr field is stored as an offset as it is often used
 * against both the physical and mapped addresses.
 */
struct sm501_mem {
    unsigned long    size;
    unsigned long    sm_addr;   /* offset from base of sm501 fb. */
    void __iomem    *k_addr;
};

/* private data that is shared between all frambuffers* */
struct sm501fb_info {
    struct device       *dev;
    struct fb_info      *fb[2];     /* fb info for both heads */
    struct resource     *fbmem_res; /* framebuffer resource */
    struct resource     *regs_res;  /* registers resource */
    struct resource     *regs2d_res;    /* 2d registers resource */
    struct sm501_platdata_fb *pdata;    /* our platform data */

    unsigned long        pm_crt_ctrl;   /* pm: crt ctrl save */

    int          irq;
    int          swap_endian;   /* set to swap rgb=>bgr */
    void __iomem        *regs;      /* remapped registers */
    void __iomem        *regs2d;    /* 2d remapped registers */
    void __iomem        *fbmem;     /* remapped framebuffer */
    size_t           fbmem_len; /* length of remapped region */
    u8 *edid_data;
};

/* per-framebuffer private data */
struct sm501fb_par {
    u32          pseudo_palette[16];

    enum sm501_controller    head;
    struct sm501_mem     cursor;
    struct sm501_mem     screen;
    struct fb_ops        ops;

    void            *store_fb;
    void            *store_cursor;
    void __iomem        *cursor_regs;
    struct sm501fb_info *info;
};

/* Helper functions */

static inline int h_total(struct fb_var_screeninfo *var)
{
    return var->xres + var->left_margin +
        var->right_margin + var->hsync_len;
}

static inline int v_total(struct fb_var_screeninfo *var)
{
    return var->yres + var->upper_margin +
        var->lower_margin + var->vsync_len;
}

/* sm501fb_sync_regs()
 *
 * This call is mainly for PCI bus systems where we need to
 * ensure that any writes to the bus are completed before the
 * next phase, or after completing a function.
*/

static inline void sm501fb_sync_regs(struct sm501fb_info *info)
{
    smc501_readl(info->regs);
}

/* sm501_alloc_mem
 *
 * This is an attempt to lay out memory for the two framebuffers and
 * everything else
 *
 * |fbmem_res->start                           fbmem_res->end|
 * |                                         |
 * |fb[0].fix.smem_start    |         |fb[1].fix.smem_start    |     2K      |
 * |-> fb[0].fix.smem_len <-| spare   |-> fb[1].fix.smem_len <-|-> cursors <-|
 *
 * The "spare" space is for the 2d engine data
 * the fixed is space for the cursors (2x1Kbyte)
 *
 * we need to allocate memory for the 2D acceleration engine
 * command list and the data for the engine to deal with.
 *
 * - all allocations must be 128bit aligned
 * - cursors are 64x64x2 bits (1Kbyte)
 *
 */

#define SM501_MEMF_CURSOR       (1)
#define SM501_MEMF_PANEL        (2)
#define SM501_MEMF_CRT          (4)
#define SM501_MEMF_ACCEL        (8)

static int sm501_alloc_mem(struct sm501fb_info *inf, struct sm501_mem *mem,
               unsigned int why, size_t size, u32 smem_len)
{
    struct sm501fb_par *par;
    struct fb_info *fbi;
    unsigned int ptr;
    unsigned int end;

    switch (why) {
    case SM501_MEMF_CURSOR:
        ptr = inf->fbmem_len - size;
        inf->fbmem_len = ptr;   /* adjust available memory. */
        break;

    case SM501_MEMF_PANEL:
        if (size > inf->fbmem_len)
            return -ENOMEM;

        ptr = inf->fbmem_len - size;
        fbi = inf->fb[HEAD_CRT];

        /* round down, some programs such as directfb do not draw
         * 0,0 correctly unless the start is aligned to a page start.
         */

        if (ptr > 0)
            ptr &= ~(PAGE_SIZE - 1);

        if (fbi && ptr < smem_len)
            return -ENOMEM;

        break;

    case SM501_MEMF_CRT:
        ptr = 0;

        /* check to see if we have panel memory allocated
         * which would put an limit on available memory. */

        fbi = inf->fb[HEAD_PANEL];
        if (fbi) {
            par = fbi->par;
            end = par->screen.k_addr ? par->screen.sm_addr : inf->fbmem_len;
        } else
            end = inf->fbmem_len;

        if ((ptr + size) > end)
            return -ENOMEM;

        break;

    case SM501_MEMF_ACCEL:
        fbi = inf->fb[HEAD_CRT];
        ptr = fbi ? smem_len : 0;

        fbi = inf->fb[HEAD_PANEL];
        if (fbi) {
            par = fbi->par;
            end = par->screen.sm_addr;
        } else
            end = inf->fbmem_len;

        if ((ptr + size) > end)
            return -ENOMEM;

        break;

    default:
        return -EINVAL;
    }

    mem->size    = size;
    mem->sm_addr = ptr;
    mem->k_addr  = inf->fbmem + ptr;

    dev_dbg(inf->dev, "%s: result %08lx, %p - %u, %zd\n",
        __func__, mem->sm_addr, mem->k_addr, why, size);

    return 0;
}

/* sm501fb_ps_to_hz
 *
 * Converts a period in picoseconds to Hz.
 *
 * Note, we try to keep this in Hz to minimise rounding with
 * the limited PLL settings on the SM501.
*/

static unsigned long sm501fb_ps_to_hz(unsigned long psvalue)
{
    unsigned long long numerator=1000000000000ULL;

    /* 10^12 / picosecond period gives frequency in Hz */
    do_div(numerator, psvalue);
    return (unsigned long)numerator;
}

/* sm501fb_hz_to_ps is identical to the opposite transform */

#define sm501fb_hz_to_ps(x) sm501fb_ps_to_hz(x)

/* sm501fb_setup_gamma
 *
 * Programs a linear 1.0 gamma ramp in case the gamma
 * correction is enabled without programming anything else.
*/

static void sm501fb_setup_gamma(struct sm501fb_info *fbi,
                unsigned long palette)
{
    unsigned long value = 0;
    int offset;

    /* set gamma values */
    for (offset = 0; offset < 256 * 4; offset += 4) {
        smc501_writel(value, fbi->regs + palette + offset);
        value += 0x010101;  /* Advance RGB by 1,1,1.*/
    }
}

/* sm501fb_check_var
 *
 * check common variables for both panel and crt
*/

static int sm501fb_check_var(struct fb_var_screeninfo *var,
                 struct fb_info *info)
{
    struct sm501fb_par  *par = info->par;
    struct sm501fb_info *sm  = par->info;
    unsigned long tmp;

    /* check we can fit these values into the registers */

    if (var->hsync_len > 255 || var->vsync_len > 63)
        return -EINVAL;

    /* hdisplay end and hsync start */
    if ((var->xres + var->right_margin) > 4096)
        return -EINVAL;

    /* vdisplay end and vsync start */
    if ((var->yres + var->lower_margin) > 2048)
        return -EINVAL;

    /* hard limits of device */

    if (h_total(var) > 4096 || v_total(var) > 2048)
        return -EINVAL;

    /* check our line length is going to be 128 bit aligned */

    tmp = (var->xres * var->bits_per_pixel) / 8;
    if ((tmp & 15) != 0)
        return -EINVAL;

    /* check the virtual size */

    if (var->xres_virtual > 4096 || var->yres_virtual > 2048)
        return -EINVAL;

    /* can cope with 8,16 or 32bpp */

    if (var->bits_per_pixel <= 8)
        var->bits_per_pixel = 8;
    else if (var->bits_per_pixel <= 16)
        var->bits_per_pixel = 16;
    else if (var->bits_per_pixel == 24)
        var->bits_per_pixel = 32;

    /* set r/g/b positions and validate bpp */
    switch(var->bits_per_pixel) {
    case 8:
        var->red.length     = var->bits_per_pixel;
        var->red.offset     = 0;
        var->green.length   = var->bits_per_pixel;
        var->green.offset   = 0;
        var->blue.length    = var->bits_per_pixel;
        var->blue.offset    = 0;
        var->transp.length  = 0;
        var->transp.offset  = 0;

        break;

    case 16:
        if (sm->pdata->flags & SM501_FBPD_SWAP_FB_ENDIAN) {
            var->blue.offset    = 11;
            var->green.offset   = 5;
            var->red.offset     = 0;
        } else {
            var->red.offset     = 11;
            var->green.offset   = 5;
            var->blue.offset    = 0;
        }
        var->transp.offset  = 0;

        var->red.length     = 5;
        var->green.length   = 6;
        var->blue.length    = 5;
        var->transp.length  = 0;
        break;

    case 32:
        if (sm->pdata->flags & SM501_FBPD_SWAP_FB_ENDIAN) {
            var->transp.offset  = 0;
            var->red.offset     = 8;
            var->green.offset   = 16;
            var->blue.offset    = 24;
        } else {
            var->transp.offset  = 24;
            var->red.offset     = 16;
            var->green.offset   = 8;
            var->blue.offset    = 0;
        }

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

    default:
        return -EINVAL;
    }

    return 0;
}

/*
 * sm501fb_check_var_crt():
 *
 * check the parameters for the CRT head, and either bring them
 * back into range, or return -EINVAL.
*/

static int sm501fb_check_var_crt(struct fb_var_screeninfo *var,
                 struct fb_info *info)
{
    return sm501fb_check_var(var, info);
}

/* sm501fb_check_var_pnl():
 *
 * check the parameters for the CRT head, and either bring them
 * back into range, or return -EINVAL.
*/

static int sm501fb_check_var_pnl(struct fb_var_screeninfo *var,
                 struct fb_info *info)
{
    return sm501fb_check_var(var, info);
}

/* sm501fb_set_par_common
 *
 * set common registers for framebuffers
*/

static int sm501fb_set_par_common(struct fb_info *info,
                  struct fb_var_screeninfo *var)
{
    struct sm501fb_par  *par = info->par;
    struct sm501fb_info *fbi = par->info;
    unsigned long pixclock;      /* pixelclock in Hz */
    unsigned long sm501pixclock; /* pixelclock the 501 can achieve in Hz */
    unsigned int mem_type;
    unsigned int clock_type;
    unsigned int head_addr;
    unsigned int smem_len;

    dev_dbg(fbi->dev, "%s: %dx%d, bpp = %d, virtual %dx%d\n",
        __func__, var->xres, var->yres, var->bits_per_pixel,
        var->xres_virtual, var->yres_virtual);

    switch (par->head) {
    case HEAD_CRT:
        mem_type = SM501_MEMF_CRT;
        clock_type = SM501_CLOCK_V2XCLK;
        head_addr = SM501_DC_CRT_FB_ADDR;
        break;

    case HEAD_PANEL:
        mem_type = SM501_MEMF_PANEL;
        clock_type = SM501_CLOCK_P2XCLK;
        head_addr = SM501_DC_PANEL_FB_ADDR;
        break;

    default:
        mem_type = 0;       /* stop compiler warnings */
        head_addr = 0;
        clock_type = 0;
    }

    switch (var->bits_per_pixel) {
    case 8:
        info->fix.visual = FB_VISUAL_PSEUDOCOLOR;
        break;

    case 16:
        info->fix.visual = FB_VISUAL_TRUECOLOR;
        break;

    case 32:
        info->fix.visual = FB_VISUAL_TRUECOLOR;
        break;
    }

    /* allocate fb memory within 501 */
    info->fix.line_length = (var->xres_virtual * var->bits_per_pixel)/8;
    smem_len = info->fix.line_length * var->yres_virtual;

    dev_dbg(fbi->dev, "%s: line length = %u\n", __func__,
        info->fix.line_length);

    if (sm501_alloc_mem(fbi, &par->screen, mem_type, smem_len, smem_len)) {
        dev_err(fbi->dev, "no memory available\n");
        return -ENOMEM;
    }

    mutex_lock(&info->mm_lock);
    info->fix.smem_start = fbi->fbmem_res->start + par->screen.sm_addr;
    info->fix.smem_len   = smem_len;
    mutex_unlock(&info->mm_lock);

    info->screen_base = fbi->fbmem + par->screen.sm_addr;
    info->screen_size = info->fix.smem_len;

    /* set start of framebuffer to the screen */

    smc501_writel(par->screen.sm_addr | SM501_ADDR_FLIP,
            fbi->regs + head_addr);

    /* program CRT clock  */

    pixclock = sm501fb_ps_to_hz(var->pixclock);

    sm501pixclock = sm501_set_clock(fbi->dev->parent, clock_type,
                    pixclock);

    /* update fb layer with actual clock used */
    var->pixclock = sm501fb_hz_to_ps(sm501pixclock);

    dev_dbg(fbi->dev, "%s: pixclock(ps) = %u, pixclock(Hz)  = %lu, "
           "sm501pixclock = %lu,  error = %ld%%\n",
           __func__, var->pixclock, pixclock, sm501pixclock,
           ((pixclock - sm501pixclock)*100)/pixclock);

    return 0;
}

/* sm501fb_set_par_geometry
 *
 * set the geometry registers for specified framebuffer.
*/

static void sm501fb_set_par_geometry(struct fb_info *info,
                     struct fb_var_screeninfo *var)
{
    struct sm501fb_par  *par = info->par;
    struct sm501fb_info *fbi = par->info;
    void __iomem *base = fbi->regs;
    unsigned long reg;

    if (par->head == HEAD_CRT)
        base += SM501_DC_CRT_H_TOT;
    else
        base += SM501_DC_PANEL_H_TOT;

    /* set framebuffer width and display width */

    reg = info->fix.line_length;
    reg |= ((var->xres * var->bits_per_pixel)/8) << 16;

    smc501_writel(reg, fbi->regs + (par->head == HEAD_CRT ?
            SM501_DC_CRT_FB_OFFSET :  SM501_DC_PANEL_FB_OFFSET));

    /* program horizontal total */

    reg  = (h_total(var) - 1) << 16;
    reg |= (var->xres - 1);

    smc501_writel(reg, base + SM501_OFF_DC_H_TOT);

    /* program horizontal sync */

    reg  = var->hsync_len << 16;
    reg |= var->xres + var->right_margin - 1;

    smc501_writel(reg, base + SM501_OFF_DC_H_SYNC);

    /* program vertical total */

    reg  = (v_total(var) - 1) << 16;
    reg |= (var->yres - 1);

    smc501_writel(reg, base + SM501_OFF_DC_V_TOT);

    /* program vertical sync */
    reg  = var->vsync_len << 16;
    reg |= var->yres + var->lower_margin - 1;

    smc501_writel(reg, base + SM501_OFF_DC_V_SYNC);
}

/* sm501fb_pan_crt
 *
 * pan the CRT display output within an virtual framebuffer
*/

static int sm501fb_pan_crt(struct fb_var_screeninfo *var,
               struct fb_info *info)
{
    struct sm501fb_par  *par = info->par;
    struct sm501fb_info *fbi = par->info;
    unsigned int bytes_pixel = info->var.bits_per_pixel / 8;
    unsigned long reg;
    unsigned long xoffs;

    xoffs = var->xoffset * bytes_pixel;

    reg = smc501_readl(fbi->regs + SM501_DC_CRT_CONTROL);

    reg &= ~SM501_DC_CRT_CONTROL_PIXEL_MASK;
    reg |= ((xoffs & 15) / bytes_pixel) << 4;
    smc501_writel(reg, fbi->regs + SM501_DC_CRT_CONTROL);

    reg = (par->screen.sm_addr + xoffs +
           var->yoffset * info->fix.line_length);
    smc501_writel(reg | SM501_ADDR_FLIP, fbi->regs + SM501_DC_CRT_FB_ADDR);

    sm501fb_sync_regs(fbi);
    return 0;
}

/* sm501fb_pan_pnl
 *
 * pan the panel display output within an virtual framebuffer
*/

static int sm501fb_pan_pnl(struct fb_var_screeninfo *var,
               struct fb_info *info)
{
    struct sm501fb_par  *par = info->par;
    struct sm501fb_info *fbi = par->info;
    unsigned long reg;

    reg = var->xoffset | (info->var.xres_virtual << 16);
    smc501_writel(reg, fbi->regs + SM501_DC_PANEL_FB_WIDTH);

    reg = var->yoffset | (info->var.yres_virtual << 16);
    smc501_writel(reg, fbi->regs + SM501_DC_PANEL_FB_HEIGHT);

    sm501fb_sync_regs(fbi);
    return 0;
}

/* sm501fb_set_par_crt
 *
 * Set the CRT video mode from the fb_info structure
*/

static int sm501fb_set_par_crt(struct fb_info *info)
{
    struct sm501fb_par  *par = info->par;
    struct sm501fb_info *fbi = par->info;
    struct fb_var_screeninfo *var = &info->var;
    unsigned long control;       /* control register */
    int ret;

    /* activate new configuration */

    dev_dbg(fbi->dev, "%s(%p)\n", __func__, info);

    /* enable CRT DAC - note 0 is on!*/
    sm501_misc_control(fbi->dev->parent, 0, SM501_MISC_DAC_POWER);

    control = smc501_readl(fbi->regs + SM501_DC_CRT_CONTROL);

    control &= (SM501_DC_CRT_CONTROL_PIXEL_MASK |
            SM501_DC_CRT_CONTROL_GAMMA |
            SM501_DC_CRT_CONTROL_BLANK |
            SM501_DC_CRT_CONTROL_SEL |
            SM501_DC_CRT_CONTROL_CP |
            SM501_DC_CRT_CONTROL_TVP);

    /* set the sync polarities before we check data source  */

    if ((var->sync & FB_SYNC_HOR_HIGH_ACT) == 0)
        control |= SM501_DC_CRT_CONTROL_HSP;

    if ((var->sync & FB_SYNC_VERT_HIGH_ACT) == 0)
        control |= SM501_DC_CRT_CONTROL_VSP;

    if ((control & SM501_DC_CRT_CONTROL_SEL) == 0) {
        /* the head is displaying panel data... */

        sm501_alloc_mem(fbi, &par->screen, SM501_MEMF_CRT, 0,
                info->fix.smem_len);
        goto out_update;
    }

    ret = sm501fb_set_par_common(info, var);
    if (ret) {
        dev_err(fbi->dev, "failed to set common parameters\n");
        return ret;
    }

    sm501fb_pan_crt(var, info);
    sm501fb_set_par_geometry(info, var);

    control |= SM501_FIFO_3;    /* fill if >3 free slots */

    switch(var->bits_per_pixel) {
    case 8:
        control |= SM501_DC_CRT_CONTROL_8BPP;
        break;

    case 16:
        control |= SM501_DC_CRT_CONTROL_16BPP;
        sm501fb_setup_gamma(fbi, SM501_DC_CRT_PALETTE);
        break;

    case 32:
        control |= SM501_DC_CRT_CONTROL_32BPP;
        sm501fb_setup_gamma(fbi, SM501_DC_CRT_PALETTE);
        break;

    default:
        BUG();
    }

    control |= SM501_DC_CRT_CONTROL_SEL;    /* CRT displays CRT data */
    control |= SM501_DC_CRT_CONTROL_TE; /* enable CRT timing */
    control |= SM501_DC_CRT_CONTROL_ENABLE; /* enable CRT plane */

 out_update:
    dev_dbg(fbi->dev, "new control is %08lx\n", control);

    smc501_writel(control, fbi->regs + SM501_DC_CRT_CONTROL);
    sm501fb_sync_regs(fbi);

    return 0;
}

static void sm501fb_panel_power(struct sm501fb_info *fbi, int to)
{
    unsigned long control;
    void __iomem *ctrl_reg = fbi->regs + SM501_DC_PANEL_CONTROL;
    struct sm501_platdata_fbsub *pd = fbi->pdata->fb_pnl;

    control = smc501_readl(ctrl_reg);

    if (to && (control & SM501_DC_PANEL_CONTROL_VDD) == 0) {
        /* enable panel power */

        control |= SM501_DC_PANEL_CONTROL_VDD;  /* FPVDDEN */
        smc501_writel(control, ctrl_reg);
        sm501fb_sync_regs(fbi);
        mdelay(10);

        control |= SM501_DC_PANEL_CONTROL_DATA; /* DATA */
        smc501_writel(control, ctrl_reg);
        sm501fb_sync_regs(fbi);
        mdelay(10);

        /* VBIASEN */

        if (!(pd->flags & SM501FB_FLAG_PANEL_NO_VBIASEN)) {
            if (pd->flags & SM501FB_FLAG_PANEL_INV_VBIASEN)
                control &= ~SM501_DC_PANEL_CONTROL_BIAS;
            else
                control |= SM501_DC_PANEL_CONTROL_BIAS;

            smc501_writel(control, ctrl_reg);
            sm501fb_sync_regs(fbi);
            mdelay(10);
        }

        if (!(pd->flags & SM501FB_FLAG_PANEL_NO_FPEN)) {
            if (pd->flags & SM501FB_FLAG_PANEL_INV_FPEN)
                control &= ~SM501_DC_PANEL_CONTROL_FPEN;
            else
                control |= SM501_DC_PANEL_CONTROL_FPEN;

            smc501_writel(control, ctrl_reg);
            sm501fb_sync_regs(fbi);
            mdelay(10);
        }
    } else if (!to && (control & SM501_DC_PANEL_CONTROL_VDD) != 0) {
        /* disable panel power */
        if (!(pd->flags & SM501FB_FLAG_PANEL_NO_FPEN)) {
            if (pd->flags & SM501FB_FLAG_PANEL_INV_FPEN)
                control |= SM501_DC_PANEL_CONTROL_FPEN;
            else
                control &= ~SM501_DC_PANEL_CONTROL_FPEN;

            smc501_writel(control, ctrl_reg);
            sm501fb_sync_regs(fbi);
            mdelay(10);
        }

        if (!(pd->flags & SM501FB_FLAG_PANEL_NO_VBIASEN)) {
            if (pd->flags & SM501FB_FLAG_PANEL_INV_VBIASEN)
                control |= SM501_DC_PANEL_CONTROL_BIAS;
            else
                control &= ~SM501_DC_PANEL_CONTROL_BIAS;

            smc501_writel(control, ctrl_reg);
            sm501fb_sync_regs(fbi);
            mdelay(10);
        }

        control &= ~SM501_DC_PANEL_CONTROL_DATA;
        smc501_writel(control, ctrl_reg);
        sm501fb_sync_regs(fbi);
        mdelay(10);

        control &= ~SM501_DC_PANEL_CONTROL_VDD;
        smc501_writel(control, ctrl_reg);
        sm501fb_sync_regs(fbi);
        mdelay(10);
    }

    sm501fb_sync_regs(fbi);
}

/* sm501fb_set_par_pnl
 *
 * Set the panel video mode from the fb_info structure
*/

static int sm501fb_set_par_pnl(struct fb_info *info)
{
    struct sm501fb_par  *par = info->par;
    struct sm501fb_info *fbi = par->info;
    struct fb_var_screeninfo *var = &info->var;
    unsigned long control;
    unsigned long reg;
    int ret;

    dev_dbg(fbi->dev, "%s(%p)\n", __func__, info);

    /* activate this new configuration */

    ret = sm501fb_set_par_common(info, var);
    if (ret)
        return ret;

    sm501fb_pan_pnl(var, info);
    sm501fb_set_par_geometry(info, var);

    /* update control register */

    control = smc501_readl(fbi->regs + SM501_DC_PANEL_CONTROL);
    control &= (SM501_DC_PANEL_CONTROL_GAMMA |
            SM501_DC_PANEL_CONTROL_VDD  |
            SM501_DC_PANEL_CONTROL_DATA |
            SM501_DC_PANEL_CONTROL_BIAS |
            SM501_DC_PANEL_CONTROL_FPEN |
            SM501_DC_PANEL_CONTROL_CP |
            SM501_DC_PANEL_CONTROL_CK |
            SM501_DC_PANEL_CONTROL_HP |
            SM501_DC_PANEL_CONTROL_VP |
            SM501_DC_PANEL_CONTROL_HPD |
            SM501_DC_PANEL_CONTROL_VPD);

    control |= SM501_FIFO_3;    /* fill if >3 free slots */

    switch(var->bits_per_pixel) {
    case 8:
        control |= SM501_DC_PANEL_CONTROL_8BPP;
        break;

    case 16:
        control |= SM501_DC_PANEL_CONTROL_16BPP;
        sm501fb_setup_gamma(fbi, SM501_DC_PANEL_PALETTE);
        break;

    case 32:
        control |= SM501_DC_PANEL_CONTROL_32BPP;
        sm501fb_setup_gamma(fbi, SM501_DC_PANEL_PALETTE);
        break;

    default:
        BUG();
    }

    smc501_writel(0x0, fbi->regs + SM501_DC_PANEL_PANNING_CONTROL);

    /* panel plane top left and bottom right location */

    smc501_writel(0x00, fbi->regs + SM501_DC_PANEL_TL_LOC);

    reg  = var->xres - 1;
    reg |= (var->yres - 1) << 16;

    smc501_writel(reg, fbi->regs + SM501_DC_PANEL_BR_LOC);

    /* program panel control register */

    control |= SM501_DC_PANEL_CONTROL_TE;   /* enable PANEL timing */
    control |= SM501_DC_PANEL_CONTROL_EN;   /* enable PANEL gfx plane */

    if ((var->sync & FB_SYNC_HOR_HIGH_ACT) == 0)
        control |= SM501_DC_PANEL_CONTROL_HSP;

    if ((var->sync & FB_SYNC_VERT_HIGH_ACT) == 0)
        control |= SM501_DC_PANEL_CONTROL_VSP;

    smc501_writel(control, fbi->regs + SM501_DC_PANEL_CONTROL);
    sm501fb_sync_regs(fbi);

    /* ensure the panel interface is not tristated at this point */

    sm501_modify_reg(fbi->dev->parent, SM501_SYSTEM_CONTROL,
             0, SM501_SYSCTRL_PANEL_TRISTATE);

    /* power the panel up */
    sm501fb_panel_power(fbi, 1);
    return 0;
}


/* chan_to_field
 *
 * convert a colour value into a field position
 *
 * from pxafb.c
*/

static inline unsigned int chan_to_field(unsigned int chan,
                     struct fb_bitfield *bf)
{
    chan &= 0xffff;
    chan >>= 16 - bf->length;
    return chan << bf->offset;
}

/* sm501fb_setcolreg
 *
 * set the colour mapping for modes that support palettised data
*/

static int sm501fb_setcolreg(unsigned regno,
                 unsigned red, unsigned green, unsigned blue,
                 unsigned transp, struct fb_info *info)
{
    struct sm501fb_par  *par = info->par;
    struct sm501fb_info *fbi = par->info;
    void __iomem *base = fbi->regs;
    unsigned int val;

    if (par->head == HEAD_CRT)
        base += SM501_DC_CRT_PALETTE;
    else
        base += SM501_DC_PANEL_PALETTE;

    switch (info->fix.visual) {
    case FB_VISUAL_TRUECOLOR:
        /* true-colour, use pseuo-palette */

        if (regno < 16) {
            u32 *pal = par->pseudo_palette;

            val  = chan_to_field(red,   &info->var.red);
            val |= chan_to_field(green, &info->var.green);
            val |= chan_to_field(blue,  &info->var.blue);

            pal[regno] = val;
        }
        break;

    case FB_VISUAL_PSEUDOCOLOR:
        if (regno < 256) {
            val = (red >> 8) << 16;
            val |= (green >> 8) << 8;
            val |= blue >> 8;

            smc501_writel(val, base + (regno * 4));
        }

        break;

    default:
        return 1;   /* unknown type */
    }

    return 0;
}

/* sm501fb_blank_pnl
 *
 * Blank or un-blank the panel interface
*/

static int sm501fb_blank_pnl(int blank_mode, struct fb_info *info)
{
    struct sm501fb_par  *par = info->par;
    struct sm501fb_info *fbi = par->info;

    dev_dbg(fbi->dev, "%s(mode=%d, %p)\n", __func__, blank_mode, info);

    switch (blank_mode) {
    case FB_BLANK_POWERDOWN:
        sm501fb_panel_power(fbi, 0);
        break;

    case FB_BLANK_UNBLANK:
        sm501fb_panel_power(fbi, 1);
        break;

    case FB_BLANK_NORMAL:
    case FB_BLANK_VSYNC_SUSPEND:
    case FB_BLANK_HSYNC_SUSPEND:
    default:
        return 1;
    }

    return 0;
}

/* sm501fb_blank_crt
 *
 * Blank or un-blank the crt interface
*/

static int sm501fb_blank_crt(int blank_mode, struct fb_info *info)
{
    struct sm501fb_par  *par = info->par;
    struct sm501fb_info *fbi = par->info;
    unsigned long ctrl;

    dev_dbg(fbi->dev, "%s(mode=%d, %p)\n", __func__, blank_mode, info);

    ctrl = smc501_readl(fbi->regs + SM501_DC_CRT_CONTROL);

    switch (blank_mode) {
    case FB_BLANK_POWERDOWN:
        ctrl &= ~SM501_DC_CRT_CONTROL_ENABLE;
        sm501_misc_control(fbi->dev->parent, SM501_MISC_DAC_POWER, 0);

    case FB_BLANK_NORMAL:
        ctrl |= SM501_DC_CRT_CONTROL_BLANK;
        break;

    case FB_BLANK_UNBLANK:
        ctrl &= ~SM501_DC_CRT_CONTROL_BLANK;
        ctrl |=  SM501_DC_CRT_CONTROL_ENABLE;
        sm501_misc_control(fbi->dev->parent, 0, SM501_MISC_DAC_POWER);
        break;

    case FB_BLANK_VSYNC_SUSPEND:
    case FB_BLANK_HSYNC_SUSPEND:
    default:
        return 1;

    }

    smc501_writel(ctrl, fbi->regs + SM501_DC_CRT_CONTROL);
    sm501fb_sync_regs(fbi);

    return 0;
}

/* sm501fb_cursor
 *
 * set or change the hardware cursor parameters
*/

static int sm501fb_cursor(struct fb_info *info, struct fb_cursor *cursor)
{
    struct sm501fb_par  *par = info->par;
    struct sm501fb_info *fbi = par->info;
    void __iomem *base = fbi->regs;
    unsigned long hwc_addr;
    unsigned long fg, bg;

    dev_dbg(fbi->dev, "%s(%p,%p)\n", __func__, info, cursor);

    if (par->head == HEAD_CRT)
        base += SM501_DC_CRT_HWC_BASE;
    else
        base += SM501_DC_PANEL_HWC_BASE;

    /* check not being asked to exceed capabilities */

    if (cursor->image.width > 64)
        return -EINVAL;

    if (cursor->image.height > 64)
        return -EINVAL;

    if (cursor->image.depth > 1)
        return -EINVAL;

    hwc_addr = smc501_readl(base + SM501_OFF_HWC_ADDR);

    if (cursor->enable)
        smc501_writel(hwc_addr | SM501_HWC_EN,
                base + SM501_OFF_HWC_ADDR);
    else
        smc501_writel(hwc_addr & ~SM501_HWC_EN,
                base + SM501_OFF_HWC_ADDR);

    /* set data */
    if (cursor->set & FB_CUR_SETPOS) {
        unsigned int x = cursor->image.dx;
        unsigned int y = cursor->image.dy;

        if (x >= 2048 || y >= 2048 )
            return -EINVAL;

        dev_dbg(fbi->dev, "set position %d,%d\n", x, y);

        //y += cursor->image.height;

        smc501_writel(x | (y << 16), base + SM501_OFF_HWC_LOC);
    }

    if (cursor->set & FB_CUR_SETCMAP) {
        unsigned int bg_col = cursor->image.bg_color;
        unsigned int fg_col = cursor->image.fg_color;

        dev_dbg(fbi->dev, "%s: update cmap (%08x,%08x)\n",
            __func__, bg_col, fg_col);

        bg = ((info->cmap.red[bg_col] & 0xF8) << 8) |
            ((info->cmap.green[bg_col] & 0xFC) << 3) |
            ((info->cmap.blue[bg_col] & 0xF8) >> 3);

        fg = ((info->cmap.red[fg_col] & 0xF8) << 8) |
            ((info->cmap.green[fg_col] & 0xFC) << 3) |
            ((info->cmap.blue[fg_col] & 0xF8) >> 3);

        dev_dbg(fbi->dev, "fgcol %08lx, bgcol %08lx\n", fg, bg);

        smc501_writel(bg, base + SM501_OFF_HWC_COLOR_1_2);
        smc501_writel(fg, base + SM501_OFF_HWC_COLOR_3);
    }

    if (cursor->set & FB_CUR_SETSIZE ||
        cursor->set & (FB_CUR_SETIMAGE | FB_CUR_SETSHAPE)) {
        /* SM501 cursor is a two bpp 64x64 bitmap this routine
         * clears it to transparent then combines the cursor
         * shape plane with the colour plane to set the
         * cursor */
        int x, y;
        const unsigned char *pcol = cursor->image.data;
        const unsigned char *pmsk = cursor->mask;
        void __iomem   *dst = par->cursor.k_addr;
        unsigned char  dcol = 0;
        unsigned char  dmsk = 0;
        unsigned int   op;

        dev_dbg(fbi->dev, "%s: setting shape (%d,%d)\n",
            __func__, cursor->image.width, cursor->image.height);

        for (op = 0; op < (64*64*2)/8; op+=4)
            smc501_writel(0x0, dst + op);

        for (y = 0; y < cursor->image.height; y++) {
            for (x = 0; x < cursor->image.width; x++) {
                if ((x % 8) == 0) {
                    dcol = *pcol++;
                    dmsk = *pmsk++;
                } else {
                    dcol >>= 1;
                    dmsk >>= 1;
                }

                if (dmsk & 1) {
                    op = (dcol & 1) ? 1 : 3;
                    op <<= ((x % 4) * 2);

                    op |= readb(dst + (x / 4));
                    writeb(op, dst + (x / 4));
                }
            }
            dst += (64*2)/8;
        }
    }

    sm501fb_sync_regs(fbi); /* ensure cursor data flushed */
    return 0;
}

/* sm501fb_crtsrc_show
 *
 * device attribute code to show where the crt output is sourced from
*/

static ssize_t sm501fb_crtsrc_show(struct device *dev,
                   struct device_attribute *attr, char *buf)
{
    struct sm501fb_info *info = dev_get_drvdata(dev);
    unsigned long ctrl;

    ctrl = smc501_readl(info->regs + SM501_DC_CRT_CONTROL);
    ctrl &= SM501_DC_CRT_CONTROL_SEL;

    return snprintf(buf, PAGE_SIZE, "%s\n", ctrl ? "crt" : "panel");
}

/* sm501fb_crtsrc_show
 *
 * device attribute code to set where the crt output is sourced from
*/

static ssize_t sm501fb_crtsrc_store(struct device *dev,
                struct device_attribute *attr,
                const char *buf, size_t len)
{
    struct sm501fb_info *info = dev_get_drvdata(dev);
    enum sm501_controller head;
    unsigned long ctrl;

    if (len < 1)
        return -EINVAL;

    if (strnicmp(buf, "crt", 3) == 0)
        head = HEAD_CRT;
    else if (strnicmp(buf, "panel", 5) == 0)
        head = HEAD_PANEL;
    else
        return -EINVAL;

    dev_info(dev, "setting crt source to head %d\n", head);

    ctrl = smc501_readl(info->regs + SM501_DC_CRT_CONTROL);

    if (head == HEAD_CRT) {
        ctrl |= SM501_DC_CRT_CONTROL_SEL;
        ctrl |= SM501_DC_CRT_CONTROL_ENABLE;
        ctrl |= SM501_DC_CRT_CONTROL_TE;
    } else {
        ctrl &= ~SM501_DC_CRT_CONTROL_SEL;
        ctrl &= ~SM501_DC_CRT_CONTROL_ENABLE;
        ctrl &= ~SM501_DC_CRT_CONTROL_TE;
    }

    smc501_writel(ctrl, info->regs + SM501_DC_CRT_CONTROL);
    sm501fb_sync_regs(info);

    return len;
}

/* Prepare the device_attr for registration with sysfs later */
static DEVICE_ATTR(crt_src, 0666, sm501fb_crtsrc_show, sm501fb_crtsrc_store);

/* sm501fb_show_regs
 *
 * show the primary sm501 registers
*/
static int sm501fb_show_regs(struct sm501fb_info *info, char *ptr,
                 unsigned int start, unsigned int len)
{
    void __iomem *mem = info->regs;
    char *buf = ptr;
    unsigned int reg;

    for (reg = start; reg < (len + start); reg += 4)
        ptr += sprintf(ptr, "%08x = %08x\n", reg,
                smc501_readl(mem + reg));

    return ptr - buf;
}

/* sm501fb_debug_show_crt
 *
 * show the crt control and cursor registers
*/

static ssize_t sm501fb_debug_show_crt(struct device *dev,
                  struct device_attribute *attr, char *buf)
{
    struct sm501fb_info *info = dev_get_drvdata(dev);
    char *ptr = buf;

    ptr += sm501fb_show_regs(info, ptr, SM501_DC_CRT_CONTROL, 0x40);
    ptr += sm501fb_show_regs(info, ptr, SM501_DC_CRT_HWC_BASE, 0x10);

    return ptr - buf;
}

static DEVICE_ATTR(fbregs_crt, 0444, sm501fb_debug_show_crt, NULL);

/* sm501fb_debug_show_pnl
 *
 * show the panel control and cursor registers
*/

static ssize_t sm501fb_debug_show_pnl(struct device *dev,
                  struct device_attribute *attr, char *buf)
{
    struct sm501fb_info *info = dev_get_drvdata(dev);
    char *ptr = buf;

    ptr += sm501fb_show_regs(info, ptr, 0x0, 0x40);
    ptr += sm501fb_show_regs(info, ptr, SM501_DC_PANEL_HWC_BASE, 0x10);

    return ptr - buf;
}

static DEVICE_ATTR(fbregs_pnl, 0444, sm501fb_debug_show_pnl, NULL);

/* acceleration operations */
static int sm501fb_sync(struct fb_info *info)
{
    int count = 1000000;
    struct sm501fb_par  *par = info->par;
    struct sm501fb_info *fbi = par->info;

    /* wait for the 2d engine to be ready */
    while ((count > 0) &&
           (smc501_readl(fbi->regs + SM501_SYSTEM_CONTROL) &
        SM501_SYSCTRL_2D_ENGINE_STATUS) != 0)
        count--;

    if (count <= 0) {
        dev_err(info->dev, "Timeout waiting for 2d engine sync\n");
        return 1;
    }
    return 0;
}

static void sm501fb_copyarea(struct fb_info *info, const struct fb_copyarea *area)
{
    struct sm501fb_par  *par = info->par;
    struct sm501fb_info *fbi = par->info;
    int width = area->width;
    int height = area->height;
    int sx = area->sx;
    int sy = area->sy;
    int dx = area->dx;
    int dy = area->dy;
    unsigned long rtl = 0;

    /* source clip */
    if ((sx >= info->var.xres_virtual) ||
        (sy >= info->var.yres_virtual))
        /* source Area not within virtual screen, skipping */
        return;
    if ((sx + width) >= info->var.xres_virtual)
        width = info->var.xres_virtual - sx - 1;
    if ((sy + height) >= info->var.yres_virtual)
        height = info->var.yres_virtual - sy - 1;

    /* dest clip */
    if ((dx >= info->var.xres_virtual) ||
        (dy >= info->var.yres_virtual))
        /* Destination Area not within virtual screen, skipping */
        return;
    if ((dx + width) >= info->var.xres_virtual)
        width = info->var.xres_virtual - dx - 1;
    if ((dy + height) >= info->var.yres_virtual)
        height = info->var.yres_virtual - dy - 1;

    if ((sx < dx) || (sy < dy)) {
        rtl = 1 << 27;
        sx += width - 1;
        dx += width - 1;
        sy += height - 1;
        dy += height - 1;
    }

    if (sm501fb_sync(info))
        return;

    /* set the base addresses */
    smc501_writel(par->screen.sm_addr, fbi->regs2d + SM501_2D_SOURCE_BASE);
    smc501_writel(par->screen.sm_addr,
            fbi->regs2d + SM501_2D_DESTINATION_BASE);

    /* set the window width */
    smc501_writel((info->var.xres << 16) | info->var.xres,
           fbi->regs2d + SM501_2D_WINDOW_WIDTH);

    /* set window stride */
    smc501_writel((info->var.xres_virtual << 16) | info->var.xres_virtual,
           fbi->regs2d + SM501_2D_PITCH);

    /* set data format */
    switch (info->var.bits_per_pixel) {
    case 8:
        smc501_writel(0, fbi->regs2d + SM501_2D_STRETCH);
        break;
    case 16:
        smc501_writel(0x00100000, fbi->regs2d + SM501_2D_STRETCH);
        break;
    case 32:
        smc501_writel(0x00200000, fbi->regs2d + SM501_2D_STRETCH);
        break;
    }

    /* 2d compare mask */
    smc501_writel(0xffffffff, fbi->regs2d + SM501_2D_COLOR_COMPARE_MASK);

    /* 2d mask */
    smc501_writel(0xffffffff, fbi->regs2d + SM501_2D_MASK);

    /* source and destination x y */
    smc501_writel((sx << 16) | sy, fbi->regs2d + SM501_2D_SOURCE);
    smc501_writel((dx << 16) | dy, fbi->regs2d + SM501_2D_DESTINATION);

    /* w/h */
    smc501_writel((width << 16) | height, fbi->regs2d + SM501_2D_DIMENSION);

    /* do area move */
    smc501_writel(0x800000cc | rtl, fbi->regs2d + SM501_2D_CONTROL);
}

static void sm501fb_fillrect(struct fb_info *info, const struct fb_fillrect *rect)
{
    struct sm501fb_par  *par = info->par;
    struct sm501fb_info *fbi = par->info;
    int width = rect->width, height = rect->height;

    if ((rect->dx >= info->var.xres_virtual) ||
        (rect->dy >= info->var.yres_virtual))
        /* Rectangle not within virtual screen, skipping */
        return;
    if ((rect->dx + width) >= info->var.xres_virtual)
        width = info->var.xres_virtual - rect->dx - 1;
    if ((rect->dy + height) >= info->var.yres_virtual)
        height = info->var.yres_virtual - rect->dy - 1;

    if (sm501fb_sync(info))
        return;

    /* set the base addresses */
    smc501_writel(par->screen.sm_addr, fbi->regs2d + SM501_2D_SOURCE_BASE);
    smc501_writel(par->screen.sm_addr,
            fbi->regs2d + SM501_2D_DESTINATION_BASE);

    /* set the window width */
    smc501_writel((info->var.xres << 16) | info->var.xres,
           fbi->regs2d + SM501_2D_WINDOW_WIDTH);

    /* set window stride */
    smc501_writel((info->var.xres_virtual << 16) | info->var.xres_virtual,
           fbi->regs2d + SM501_2D_PITCH);

    /* set data format */
    switch (info->var.bits_per_pixel) {
    case 8:
        smc501_writel(0, fbi->regs2d + SM501_2D_STRETCH);
        break;
    case 16:
        smc501_writel(0x00100000, fbi->regs2d + SM501_2D_STRETCH);
        break;
    case 32:
        smc501_writel(0x00200000, fbi->regs2d + SM501_2D_STRETCH);
        break;
    }

    /* 2d compare mask */
    smc501_writel(0xffffffff, fbi->regs2d + SM501_2D_COLOR_COMPARE_MASK);

    /* 2d mask */
    smc501_writel(0xffffffff, fbi->regs2d + SM501_2D_MASK);

    /* colour */
    smc501_writel(rect->color, fbi->regs2d + SM501_2D_FOREGROUND);

    /* x y */
    smc501_writel((rect->dx << 16) | rect->dy,
            fbi->regs2d + SM501_2D_DESTINATION);

    /* w/h */
    smc501_writel((width << 16) | height, fbi->regs2d + SM501_2D_DIMENSION);

    /* do rectangle fill */
    smc501_writel(0x800100cc, fbi->regs2d + SM501_2D_CONTROL);
}


static struct fb_ops sm501fb_ops_crt = {
    .owner      = THIS_MODULE,
    .fb_check_var   = sm501fb_check_var_crt,
    .fb_set_par = sm501fb_set_par_crt,
    .fb_blank   = sm501fb_blank_crt,
    .fb_setcolreg   = sm501fb_setcolreg,
    .fb_pan_display = sm501fb_pan_crt,
    .fb_cursor  = sm501fb_cursor,
    .fb_fillrect    = sm501fb_fillrect,
    .fb_copyarea    = sm501fb_copyarea,
    .fb_imageblit   = cfb_imageblit,
    .fb_sync    = sm501fb_sync,
};

static struct fb_ops sm501fb_ops_pnl = {
    .owner      = THIS_MODULE,
    .fb_check_var   = sm501fb_check_var_pnl,
    .fb_set_par = sm501fb_set_par_pnl,
    .fb_pan_display = sm501fb_pan_pnl,
    .fb_blank   = sm501fb_blank_pnl,
    .fb_setcolreg   = sm501fb_setcolreg,
    .fb_cursor  = sm501fb_cursor,
    .fb_fillrect    = sm501fb_fillrect,
    .fb_copyarea    = sm501fb_copyarea,
    .fb_imageblit   = cfb_imageblit,
    .fb_sync    = sm501fb_sync,
};

/* sm501_init_cursor
 *
 * initialise hw cursor parameters
*/

static int sm501_init_cursor(struct fb_info *fbi, unsigned int reg_base)
{
    struct sm501fb_par *par;
    struct sm501fb_info *info;
    int ret;

    if (fbi == NULL)
        return 0;

    par = fbi->par;
    info = par->info;

    par->cursor_regs = info->regs + reg_base;

    ret = sm501_alloc_mem(info, &par->cursor, SM501_MEMF_CURSOR, 1024,
                  fbi->fix.smem_len);
    if (ret < 0)
        return ret;

    /* initialise the colour registers */

    smc501_writel(par->cursor.sm_addr,
            par->cursor_regs + SM501_OFF_HWC_ADDR);

    smc501_writel(0x00, par->cursor_regs + SM501_OFF_HWC_LOC);
    smc501_writel(0x00, par->cursor_regs + SM501_OFF_HWC_COLOR_1_2);
    smc501_writel(0x00, par->cursor_regs + SM501_OFF_HWC_COLOR_3);
    sm501fb_sync_regs(info);

    return 0;
}

/* sm501fb_info_start
 *
 * fills the par structure claiming resources and remapping etc.
*/

static int sm501fb_start(struct sm501fb_info *info,
             struct platform_device *pdev)
{
    struct resource *res;
    struct device *dev = &pdev->dev;
    int k;
    int ret;

    info->irq = ret = platform_get_irq(pdev, 0);
    if (ret < 0) {
        /* we currently do not use the IRQ */
        dev_warn(dev, "no irq for device\n");
    }

    /* allocate, reserve and remap resources for display
     * controller registers */
    res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    if (res == NULL) {
        dev_err(dev, "no resource definition for registers\n");
        ret = -ENOENT;
        goto err_release;
    }

    info->regs_res = request_mem_region(res->start,
                        resource_size(res),
                        pdev->name);

    if (info->regs_res == NULL) {
        dev_err(dev, "cannot claim registers\n");
        ret = -ENXIO;
        goto err_release;
    }

    info->regs = ioremap(res->start, resource_size(res));
    if (info->regs == NULL) {
        dev_err(dev, "cannot remap registers\n");
        ret = -ENXIO;
        goto err_regs_res;
    }

    /* allocate, reserve and remap resources for 2d
     * controller registers */
    res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
    if (res == NULL) {
        dev_err(dev, "no resource definition for 2d registers\n");
        ret = -ENOENT;
        goto err_regs_map;
    }

    info->regs2d_res = request_mem_region(res->start,
                          resource_size(res),
                          pdev->name);

    if (info->regs2d_res == NULL) {
        dev_err(dev, "cannot claim registers\n");
        ret = -ENXIO;
        goto err_regs_map;
    }

    info->regs2d = ioremap(res->start, resource_size(res));
    if (info->regs2d == NULL) {
        dev_err(dev, "cannot remap registers\n");
        ret = -ENXIO;
        goto err_regs2d_res;
    }

    /* allocate, reserve resources for framebuffer */
    res = platform_get_resource(pdev, IORESOURCE_MEM, 2);
    if (res == NULL) {
        dev_err(dev, "no memory resource defined\n");
        ret = -ENXIO;
        goto err_regs2d_map;
    }

    info->fbmem_res = request_mem_region(res->start,
                         resource_size(res),
                         pdev->name);
    if (info->fbmem_res == NULL) {
        dev_err(dev, "cannot claim framebuffer\n");
        ret = -ENXIO;
        goto err_regs2d_map;
    }

    info->fbmem = ioremap(res->start, resource_size(res));
    if (info->fbmem == NULL) {
        dev_err(dev, "cannot remap framebuffer\n");
        goto err_mem_res;
    }

    info->fbmem_len = resource_size(res);

    /* clear framebuffer memory - avoids garbage data on unused fb */
    memset(info->fbmem, 0, info->fbmem_len);

    /* clear palette ram - undefined at power on */
    for (k = 0; k < (256 * 3); k++)
        smc501_writel(0, info->regs + SM501_DC_PANEL_PALETTE + (k * 4));

    /* enable display controller */
    sm501_unit_power(dev->parent, SM501_GATE_DISPLAY, 1);

    /* enable 2d controller */
    sm501_unit_power(dev->parent, SM501_GATE_2D_ENGINE, 1);

    /* setup cursors */
    sm501_init_cursor(info->fb[HEAD_CRT], SM501_DC_CRT_HWC_ADDR);
    sm501_init_cursor(info->fb[HEAD_PANEL], SM501_DC_PANEL_HWC_ADDR);

    return 0; /* everything is setup */

 err_mem_res:
    release_mem_region(info->fbmem_res->start,
               resource_size(info->fbmem_res));

 err_regs2d_map:
    iounmap(info->regs2d);

 err_regs2d_res:
    release_mem_region(info->regs2d_res->start,
               resource_size(info->regs2d_res));

 err_regs_map:
    iounmap(info->regs);

 err_regs_res:
    release_mem_region(info->regs_res->start,
               resource_size(info->regs_res));

 err_release:
    return ret;
}

static void sm501fb_stop(struct sm501fb_info *info)
{
    /* disable display controller */
    sm501_unit_power(info->dev->parent, SM501_GATE_DISPLAY, 0);

    iounmap(info->fbmem);
    release_mem_region(info->fbmem_res->start,
               resource_size(info->fbmem_res));

    iounmap(info->regs2d);
    release_mem_region(info->regs2d_res->start,
               resource_size(info->regs2d_res));

    iounmap(info->regs);
    release_mem_region(info->regs_res->start,
               resource_size(info->regs_res));
}

static int __devinit sm501fb_init_fb(struct fb_info *fb,
               enum sm501_controller head,
               const char *fbname)
{
    struct sm501_platdata_fbsub *pd;
    struct sm501fb_par *par = fb->par;
    struct sm501fb_info *info = par->info;
    unsigned long ctrl;
    unsigned int enable;
    int ret;

    switch (head) {
    case HEAD_CRT:
        pd = info->pdata->fb_crt;
        ctrl = smc501_readl(info->regs + SM501_DC_CRT_CONTROL);
        enable = (ctrl & SM501_DC_CRT_CONTROL_ENABLE) ? 1 : 0;

        /* ensure we set the correct source register */
        if (info->pdata->fb_route != SM501_FB_CRT_PANEL) {
            ctrl |= SM501_DC_CRT_CONTROL_SEL;
            smc501_writel(ctrl, info->regs + SM501_DC_CRT_CONTROL);
        }

        break;

    case HEAD_PANEL:
        pd = info->pdata->fb_pnl;
        ctrl = smc501_readl(info->regs + SM501_DC_PANEL_CONTROL);
        enable = (ctrl & SM501_DC_PANEL_CONTROL_EN) ? 1 : 0;
        break;

    default:
        pd = NULL;      /* stop compiler warnings */
        ctrl = 0;
        enable = 0;
        BUG();
    }

    dev_info(info->dev, "fb %s %sabled at start\n",
         fbname, enable ? "en" : "dis");

    /* check to see if our routing allows this */

    if (head == HEAD_CRT && info->pdata->fb_route == SM501_FB_CRT_PANEL) {
        ctrl &= ~SM501_DC_CRT_CONTROL_SEL;
        smc501_writel(ctrl, info->regs + SM501_DC_CRT_CONTROL);
        enable = 0;
    }

    strlcpy(fb->fix.id, fbname, sizeof(fb->fix.id));

    memcpy(&par->ops,
           (head == HEAD_CRT) ? &sm501fb_ops_crt : &sm501fb_ops_pnl,
           sizeof(struct fb_ops));

    /* update ops dependent on what we've been passed */

    if ((pd->flags & SM501FB_FLAG_USE_HWCURSOR) == 0)
        par->ops.fb_cursor = NULL;

    fb->fbops = &par->ops;
    fb->flags = FBINFO_FLAG_DEFAULT | FBINFO_READS_FAST |
        FBINFO_HWACCEL_COPYAREA | FBINFO_HWACCEL_FILLRECT |
        FBINFO_HWACCEL_XPAN | FBINFO_HWACCEL_YPAN;

#if defined(CONFIG_OF)
#ifdef __BIG_ENDIAN
    if (of_get_property(info->dev->parent->of_node, "little-endian", NULL))
        fb->flags |= FBINFO_FOREIGN_ENDIAN;
#else
    if (of_get_property(info->dev->parent->of_node, "big-endian", NULL))
        fb->flags |= FBINFO_FOREIGN_ENDIAN;
#endif
#endif
    /* fixed data */

    fb->fix.type        = FB_TYPE_PACKED_PIXELS;
    fb->fix.type_aux    = 0;
    fb->fix.xpanstep    = 1;
    fb->fix.ypanstep    = 1;
    fb->fix.ywrapstep   = 0;
    fb->fix.accel       = FB_ACCEL_NONE;

    /* screenmode */

    fb->var.nonstd      = 0;
    fb->var.activate    = FB_ACTIVATE_NOW;
    fb->var.accel_flags = 0;
    fb->var.vmode       = FB_VMODE_NONINTERLACED;
    fb->var.bits_per_pixel  = 16;

    if (info->edid_data) {
            /* Now build modedb from EDID */
            fb_edid_to_monspecs(info->edid_data, &fb->monspecs);
            fb_videomode_to_modelist(fb->monspecs.modedb,
                         fb->monspecs.modedb_len,
                         &fb->modelist);
    }

    if (enable && (pd->flags & SM501FB_FLAG_USE_INIT_MODE) && 0) {
        /* TODO read the mode from the current display */
    } else {
        if (pd->def_mode) {
            dev_info(info->dev, "using supplied mode\n");
            fb_videomode_to_var(&fb->var, pd->def_mode);

            fb->var.bits_per_pixel = pd->def_bpp ? pd->def_bpp : 8;
            fb->var.xres_virtual = fb->var.xres;
            fb->var.yres_virtual = fb->var.yres;
        } else {
            if (info->edid_data) {
                ret = fb_find_mode(&fb->var, fb, fb_mode,
                    fb->monspecs.modedb,
                    fb->monspecs.modedb_len,
                    &sm501_default_mode, default_bpp);
                /* edid_data is no longer needed, free it */
                kfree(info->edid_data);
            } else {
                ret = fb_find_mode(&fb->var, fb,
                       NULL, NULL, 0, NULL, 8);
            }

            switch (ret) {
            case 1:
                dev_info(info->dev, "using mode specified in "
                        "@mode\n");
                break;
            case 2:
                dev_info(info->dev, "using mode specified in "
                    "@mode with ignored refresh rate\n");
                break;
            case 3:
                dev_info(info->dev, "using mode default "
                    "mode\n");
                break;
            case 4:
                dev_info(info->dev, "using mode from list\n");
                break;
            default:
                dev_info(info->dev, "ret = %d\n", ret);
                dev_info(info->dev, "failed to find mode\n");
                return -EINVAL;
            }
        }
    }

    /* initialise and set the palette */
    if (fb_alloc_cmap(&fb->cmap, NR_PALETTE, 0)) {
        dev_err(info->dev, "failed to allocate cmap memory\n");
        return -ENOMEM;
    }
    fb_set_cmap(&fb->cmap, fb);

    ret = (fb->fbops->fb_check_var)(&fb->var, fb);
    if (ret)
        dev_err(info->dev, "check_var() failed on initial setup?\n");

    return 0;
}

/* default platform data if none is supplied (ie, PCI device) */

static struct sm501_platdata_fbsub sm501fb_pdata_crt = {
    .flags      = (SM501FB_FLAG_USE_INIT_MODE |
               SM501FB_FLAG_USE_HWCURSOR |
               SM501FB_FLAG_USE_HWACCEL |
               SM501FB_FLAG_DISABLE_AT_EXIT),

};

static struct sm501_platdata_fbsub sm501fb_pdata_pnl = {
    .flags      = (SM501FB_FLAG_USE_INIT_MODE |
               SM501FB_FLAG_USE_HWCURSOR |
               SM501FB_FLAG_USE_HWACCEL |
               SM501FB_FLAG_DISABLE_AT_EXIT),
};

static struct sm501_platdata_fb sm501fb_def_pdata = {
    .fb_route       = SM501_FB_OWN,
    .fb_crt         = &sm501fb_pdata_crt,
    .fb_pnl         = &sm501fb_pdata_pnl,
};

static char driver_name_crt[] = "sm501fb-crt";
static char driver_name_pnl[] = "sm501fb-panel";

static int __devinit sm501fb_probe_one(struct sm501fb_info *info,
                       enum sm501_controller head)
{
    unsigned char *name = (head == HEAD_CRT) ? "crt" : "panel";
    struct sm501_platdata_fbsub *pd;
    struct sm501fb_par *par;
    struct fb_info *fbi;

    pd = (head == HEAD_CRT) ? info->pdata->fb_crt : info->pdata->fb_pnl;

    /* Do not initialise if we've not been given any platform data */
    if (pd == NULL) {
        dev_info(info->dev, "no data for fb %s (disabled)\n", name);
        return 0;
    }

    fbi = framebuffer_alloc(sizeof(struct sm501fb_par), info->dev);
    if (fbi == NULL) {
        dev_err(info->dev, "cannot allocate %s framebuffer\n", name);
        return -ENOMEM;
    }

    par = fbi->par;
    par->info = info;
    par->head = head;
    fbi->pseudo_palette = &par->pseudo_palette;

    info->fb[head] = fbi;

    return 0;
}

/* Free up anything allocated by sm501fb_init_fb */

static void sm501_free_init_fb(struct sm501fb_info *info,
                enum sm501_controller head)
{
    struct fb_info *fbi = info->fb[head];

    fb_dealloc_cmap(&fbi->cmap);
}

static int __devinit sm501fb_start_one(struct sm501fb_info *info,
                       enum sm501_controller head,
                       const char *drvname)
{
    struct fb_info *fbi = info->fb[head];
    int ret;

    if (!fbi)
        return 0;

    mutex_init(&info->fb[head]->mm_lock);

    ret = sm501fb_init_fb(info->fb[head], head, drvname);
    if (ret) {
        dev_err(info->dev, "cannot initialise fb %s\n", drvname);
        return ret;
    }

    ret = register_framebuffer(info->fb[head]);
    if (ret) {
        dev_err(info->dev, "failed to register fb %s\n", drvname);
        sm501_free_init_fb(info, head);
        return ret;
    }

    dev_info(info->dev, "fb%d: %s frame buffer\n", fbi->node, fbi->fix.id);

    return 0;
}

static int __devinit sm501fb_probe(struct platform_device *pdev)
{
    struct sm501fb_info *info;
    struct device *dev = &pdev->dev;
    int ret;

    /* allocate our framebuffers */

    info = kzalloc(sizeof(struct sm501fb_info), GFP_KERNEL);
    if (!info) {
        dev_err(dev, "failed to allocate state\n");
        return -ENOMEM;
    }

    info->dev = dev = &pdev->dev;
    platform_set_drvdata(pdev, info);

    if (dev->parent->platform_data) {
        struct sm501_platdata *pd = dev->parent->platform_data;
        info->pdata = pd->fb;
    }

    if (info->pdata == NULL) {
        int found = 0;
#if defined(CONFIG_OF)
        struct device_node *np = pdev->dev.parent->of_node;
        const u8 *prop;
        const char *cp;
        int len;

        info->pdata = &sm501fb_def_pdata;
        if (np) {
            /* Get EDID */
            cp = of_get_property(np, "mode", &len);
            if (cp)
                strcpy(fb_mode, cp);
            prop = of_get_property(np, "edid", &len);
            if (prop && len == EDID_LENGTH) {
                info->edid_data = kmemdup(prop, EDID_LENGTH,
                              GFP_KERNEL);
                if (info->edid_data)
                    found = 1;
            }
        }
#endif
        if (!found) {
            dev_info(dev, "using default configuration data\n");
            info->pdata = &sm501fb_def_pdata;
        }
    }

    /* probe for the presence of each panel */

    ret = sm501fb_probe_one(info, HEAD_CRT);
    if (ret < 0) {
        dev_err(dev, "failed to probe CRT\n");
        goto err_alloc;
    }

    ret = sm501fb_probe_one(info, HEAD_PANEL);
    if (ret < 0) {
        dev_err(dev, "failed to probe PANEL\n");
        goto err_probed_crt;
    }

    if (info->fb[HEAD_PANEL] == NULL &&
        info->fb[HEAD_CRT] == NULL) {
        dev_err(dev, "no framebuffers found\n");
        goto err_alloc;
    }

    /* get the resources for both of the framebuffers */

    ret = sm501fb_start(info, pdev);
    if (ret) {
        dev_err(dev, "cannot initialise SM501\n");
        goto err_probed_panel;
    }

    ret = sm501fb_start_one(info, HEAD_CRT, driver_name_crt);
    if (ret) {
        dev_err(dev, "failed to start CRT\n");
        goto err_started;
    }

    ret = sm501fb_start_one(info, HEAD_PANEL, driver_name_pnl);
    if (ret) {
        dev_err(dev, "failed to start Panel\n");
        goto err_started_crt;
    }

    /* create device files */

    ret = device_create_file(dev, &dev_attr_crt_src);
    if (ret)
        goto err_started_panel;

    ret = device_create_file(dev, &dev_attr_fbregs_pnl);
    if (ret)
        goto err_attached_crtsrc_file;

    ret = device_create_file(dev, &dev_attr_fbregs_crt);
    if (ret)
        goto err_attached_pnlregs_file;

    /* we registered, return ok */
    return 0;

err_attached_pnlregs_file:
    device_remove_file(dev, &dev_attr_fbregs_pnl);

err_attached_crtsrc_file:
    device_remove_file(dev, &dev_attr_crt_src);

err_started_panel:
    unregister_framebuffer(info->fb[HEAD_PANEL]);
    sm501_free_init_fb(info, HEAD_PANEL);

err_started_crt:
    unregister_framebuffer(info->fb[HEAD_CRT]);
    sm501_free_init_fb(info, HEAD_CRT);

err_started:
    sm501fb_stop(info);

err_probed_panel:
    framebuffer_release(info->fb[HEAD_PANEL]);

err_probed_crt:
    framebuffer_release(info->fb[HEAD_CRT]);

err_alloc:
    kfree(info);

    return ret;
}


/*
 *  Cleanup
 */
static int sm501fb_remove(struct platform_device *pdev)
{
    struct sm501fb_info *info = platform_get_drvdata(pdev);
    struct fb_info     *fbinfo_crt = info->fb[0];
    struct fb_info     *fbinfo_pnl = info->fb[1];

    device_remove_file(&pdev->dev, &dev_attr_fbregs_crt);
    device_remove_file(&pdev->dev, &dev_attr_fbregs_pnl);
    device_remove_file(&pdev->dev, &dev_attr_crt_src);

    sm501_free_init_fb(info, HEAD_CRT);
    sm501_free_init_fb(info, HEAD_PANEL);

    unregister_framebuffer(fbinfo_crt);
    unregister_framebuffer(fbinfo_pnl);

    sm501fb_stop(info);
    kfree(info);

    framebuffer_release(fbinfo_pnl);
    framebuffer_release(fbinfo_crt);

    return 0;
}

#ifdef CONFIG_PM

static int sm501fb_suspend_fb(struct sm501fb_info *info,
                  enum sm501_controller head)
{
    struct fb_info *fbi = info->fb[head];
    struct sm501fb_par *par = fbi->par;

    if (par->screen.size == 0)
        return 0;

    /* blank the relevant interface to ensure unit power minimised */
    (par->ops.fb_blank)(FB_BLANK_POWERDOWN, fbi);

    /* tell console/fb driver we are suspending */

    console_lock();
    fb_set_suspend(fbi, 1);
    console_unlock();

    /* backup copies in case chip is powered down over suspend */

    par->store_fb = vmalloc(par->screen.size);
    if (par->store_fb == NULL) {
        dev_err(info->dev, "no memory to store screen\n");
        return -ENOMEM;
    }

    par->store_cursor = vmalloc(par->cursor.size);
    if (par->store_cursor == NULL) {
        dev_err(info->dev, "no memory to store cursor\n");
        goto err_nocursor;
    }

    dev_dbg(info->dev, "suspending screen to %p\n", par->store_fb);
    dev_dbg(info->dev, "suspending cursor to %p\n", par->store_cursor);

    memcpy_fromio(par->store_fb, par->screen.k_addr, par->screen.size);
    memcpy_fromio(par->store_cursor, par->cursor.k_addr, par->cursor.size);

    return 0;

 err_nocursor:
    vfree(par->store_fb);
    par->store_fb = NULL;

    return -ENOMEM;
}

static void sm501fb_resume_fb(struct sm501fb_info *info,
                  enum sm501_controller head)
{
    struct fb_info *fbi = info->fb[head];
    struct sm501fb_par *par = fbi->par;

    if (par->screen.size == 0)
        return;

    /* re-activate the configuration */

    (par->ops.fb_set_par)(fbi);

    /* restore the data */

    dev_dbg(info->dev, "restoring screen from %p\n", par->store_fb);
    dev_dbg(info->dev, "restoring cursor from %p\n", par->store_cursor);

    if (par->store_fb)
        memcpy_toio(par->screen.k_addr, par->store_fb,
                par->screen.size);

    if (par->store_cursor)
        memcpy_toio(par->cursor.k_addr, par->store_cursor,
                par->cursor.size);

    console_lock();
    fb_set_suspend(fbi, 0);
    console_unlock();

    vfree(par->store_fb);
    vfree(par->store_cursor);
}


/* suspend and resume support */

static int sm501fb_suspend(struct platform_device *pdev, pm_message_t state)
{
    struct sm501fb_info *info = platform_get_drvdata(pdev);

    /* store crt control to resume with */
    info->pm_crt_ctrl = smc501_readl(info->regs + SM501_DC_CRT_CONTROL);

    sm501fb_suspend_fb(info, HEAD_CRT);
    sm501fb_suspend_fb(info, HEAD_PANEL);

    /* turn off the clocks, in case the device is not powered down */
    sm501_unit_power(info->dev->parent, SM501_GATE_DISPLAY, 0);

    return 0;
}

#define SM501_CRT_CTRL_SAVE (SM501_DC_CRT_CONTROL_TVP |        \
                 SM501_DC_CRT_CONTROL_SEL)


static int sm501fb_resume(struct platform_device *pdev)
{
    struct sm501fb_info *info = platform_get_drvdata(pdev);
    unsigned long crt_ctrl;

    sm501_unit_power(info->dev->parent, SM501_GATE_DISPLAY, 1);

    /* restore the items we want to be saved for crt control */

    crt_ctrl = smc501_readl(info->regs + SM501_DC_CRT_CONTROL);
    crt_ctrl &= ~SM501_CRT_CTRL_SAVE;
    crt_ctrl |= info->pm_crt_ctrl & SM501_CRT_CTRL_SAVE;
    smc501_writel(crt_ctrl, info->regs + SM501_DC_CRT_CONTROL);

    sm501fb_resume_fb(info, HEAD_CRT);
    sm501fb_resume_fb(info, HEAD_PANEL);

    return 0;
}

#else
#define sm501fb_suspend NULL
#define sm501fb_resume  NULL
#endif

static struct platform_driver sm501fb_driver = {
    .probe      = sm501fb_probe,
    .remove     = sm501fb_remove,
    .suspend    = sm501fb_suspend,
    .resume     = sm501fb_resume,
    .driver     = {
        .name   = "sm501-fb",
        .owner  = THIS_MODULE,
    },
};

module_platform_driver(sm501fb_driver);

module_param_named(mode, fb_mode, charp, 0);
MODULE_PARM_DESC(mode,
    "Specify resolution as \"<xres>x<yres>[-<bpp>][@<refresh>]\" ");
module_param_named(bpp, default_bpp, ulong, 0);
MODULE_PARM_DESC(bpp, "Specify bit-per-pixel if not specified mode");
MODULE_AUTHOR("Ben Dooks, Vincent Sanders");
MODULE_DESCRIPTION("SM501 Framebuffer driver");
MODULE_LICENSE("GPL v2");