// SPDX-License-Identifier: GPL-2.0-only
/*
 * A framebuffer driver for VBE 2.0+ compliant video cards
 *
 * (c) 2007 Michal Januszewski <spock@gentoo.org>
 *     Loosely based upon the vesafb driver.
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/init.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/skbuff.h>
#include <linux/timer.h>
#include <linux/completion.h>
#include <linux/connector.h>
#include <linux/random.h>
#include <linux/platform_device.h>
#include <linux/limits.h>
#include <linux/fb.h>
#include <linux/io.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <video/edid.h>
#include <video/uvesafb.h>
#ifdef CONFIG_X86
#include <video/vga.h>
#endif
#include "edid.h"

static struct cb_id uvesafb_cn_id = {
        .idx = CN_IDX_V86D,
        .val = CN_VAL_V86D_UVESAFB
};
static char v86d_path[PATH_MAX] = "/sbin/v86d";
static char v86d_started;       /* has v86d been started by uvesafb? */

static const struct fb_fix_screeninfo uvesafb_fix = {
        .id     = "VESA VGA",
        .type   = FB_TYPE_PACKED_PIXELS,
        .accel  = FB_ACCEL_NONE,
        .visual = FB_VISUAL_TRUECOLOR,
};

static int mtrr         = 3;    /* enable mtrr by default */
static bool blank       = true; /* enable blanking by default */
static int ypan         = 1;    /* 0: scroll, 1: ypan, 2: ywrap */
static bool pmi_setpal  = true; /* use PMI for palette changes */
static bool nocrtc;             /* ignore CRTC settings */
static bool noedid;             /* don't try DDC transfers */
static int vram_remap;          /* set amt. of memory to be used */
static int vram_total;          /* set total amount of memory */
static u16 maxclk;              /* maximum pixel clock */
static u16 maxvf;               /* maximum vertical frequency */
static u16 maxhf;               /* maximum horizontal frequency */
static u16 vbemode;             /* force use of a specific VBE mode */
static char *mode_option;
static u8  dac_width    = 6;

static struct uvesafb_ktask *uvfb_tasks[UVESAFB_TASKS_MAX];
static DEFINE_MUTEX(uvfb_lock);

/*
 * A handler for replies from userspace.
 *
 * Make sure each message passes consistency checks and if it does,
 * find the kernel part of the task struct, copy the registers and
 * the buffer contents and then complete the task.
 */
static void uvesafb_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
{
        struct uvesafb_task *utask;
        struct uvesafb_ktask *task;

        if (!capable(CAP_SYS_ADMIN))
                return;

        if (msg->seq >= UVESAFB_TASKS_MAX)
                return;

        mutex_lock(&uvfb_lock);
        task = uvfb_tasks[msg->seq];

        if (!task || msg->ack != task->ack) {
                mutex_unlock(&uvfb_lock);
                return;
        }

        utask = (struct uvesafb_task *)msg->data;

        /* Sanity checks for the buffer length. */
        if (task->t.buf_len < utask->buf_len ||
            utask->buf_len > msg->len - sizeof(*utask)) {
                mutex_unlock(&uvfb_lock);
                return;
        }

        uvfb_tasks[msg->seq] = NULL;
        mutex_unlock(&uvfb_lock);

        memcpy(&task->t, utask, sizeof(*utask));

        if (task->t.buf_len && task->buf)
                memcpy(task->buf, utask + 1, task->t.buf_len);

        complete(task->done);
        return;
}

static int uvesafb_helper_start(void)
{
        char *envp[] = {
                "HOME=/",
                "PATH=/sbin:/bin",
                NULL,
        };

        char *argv[] = {
                v86d_path,
                NULL,
        };

        return call_usermodehelper(v86d_path, argv, envp, UMH_WAIT_PROC);
}

/*
 * Execute a uvesafb task.
 *
 * Returns 0 if the task is executed successfully.
 *
 * A message sent to the userspace consists of the uvesafb_task
 * struct and (optionally) a buffer. The uvesafb_task struct is
 * a simplified version of uvesafb_ktask (its kernel counterpart)
 * containing only the register values, flags and the length of
 * the buffer.
 *
 * Each message is assigned a sequence number (increased linearly)
 * and a random ack number. The sequence number is used as a key
 * for the uvfb_tasks array which holds pointers to uvesafb_ktask
 * structs for all requests.
 */
static int uvesafb_exec(struct uvesafb_ktask *task)
{
        static int seq;
        struct cn_msg *m;
        int err;
        int len = sizeof(task->t) + task->t.buf_len;

        /*
         * Check whether the message isn't longer than the maximum
         * allowed by connector.
         */
        if (sizeof(*m) + len > CONNECTOR_MAX_MSG_SIZE) {
                pr_warn("message too long (%d), can't execute task\n",
                        (int)(sizeof(*m) + len));
                return -E2BIG;
        }

        m = kzalloc(sizeof(*m) + len, GFP_KERNEL);
        if (!m)
                return -ENOMEM;

        init_completion(task->done);

        memcpy(&m->id, &uvesafb_cn_id, sizeof(m->id));
        m->seq = seq;
        m->len = len;
        m->ack = get_random_u32();

        /* uvesafb_task structure */
        memcpy(m + 1, &task->t, sizeof(task->t));

        /* Buffer */
        memcpy((u8 *)(m + 1) + sizeof(task->t), task->buf, task->t.buf_len);

        /*
         * Save the message ack number so that we can find the kernel
         * part of this task when a reply is received from userspace.
         */
        task->ack = m->ack;

        mutex_lock(&uvfb_lock);

        /* If all slots are taken -- bail out. */
        if (uvfb_tasks[seq]) {
                mutex_unlock(&uvfb_lock);
                err = -EBUSY;
                goto out;
        }

        /* Save a pointer to the kernel part of the task struct. */
        uvfb_tasks[seq] = task;
        mutex_unlock(&uvfb_lock);

        err = cn_netlink_send(m, 0, 0, GFP_KERNEL);
        if (err == -ESRCH) {
                /*
                 * Try to start the userspace helper if sending
                 * the request failed the first time.
                 */
                err = uvesafb_helper_start();
                if (err) {
                        pr_err("failed to execute %s\n", v86d_path);
                        pr_err("make sure that the v86d helper is installed and executable\n");
                } else {
                        v86d_started = 1;
                        err = cn_netlink_send(m, 0, 0, gfp_any());
                        if (err == -ENOBUFS)
                                err = 0;
                }
        } else if (err == -ENOBUFS)
                err = 0;

        if (!err && !(task->t.flags & TF_EXIT))
                err = !wait_for_completion_timeout(task->done,
                                msecs_to_jiffies(UVESAFB_TIMEOUT));

        mutex_lock(&uvfb_lock);
        uvfb_tasks[seq] = NULL;
        mutex_unlock(&uvfb_lock);

        seq++;
        if (seq >= UVESAFB_TASKS_MAX)
                seq = 0;
out:
        kfree(m);
        return err;
}

/*
 * Free a uvesafb_ktask struct.
 */
static void uvesafb_free(struct uvesafb_ktask *task)
{
        if (task) {
                kfree(task->done);
                kfree(task);
        }
}

/*
 * Prepare a uvesafb_ktask struct to be used again.
 */
static void uvesafb_reset(struct uvesafb_ktask *task)
{
        struct completion *cpl = task->done;

        memset(task, 0, sizeof(*task));
        task->done = cpl;
}

/*
 * Allocate and prepare a uvesafb_ktask struct.
 */
static struct uvesafb_ktask *uvesafb_prep(void)
{
        struct uvesafb_ktask *task;

        task = kzalloc_obj(*task);
        if (task) {
                task->done = kzalloc_obj(*task->done);
                if (!task->done) {
                        kfree(task);
                        task = NULL;
                }
        }
        return task;
}

static void uvesafb_setup_var(struct fb_var_screeninfo *var,
                struct fb_info *info, struct vbe_mode_ib *mode)
{
        struct uvesafb_par *par = info->par;

        var->vmode = FB_VMODE_NONINTERLACED;
        var->sync = FB_SYNC_VERT_HIGH_ACT;

        var->xres = mode->x_res;
        var->yres = mode->y_res;
        var->xres_virtual = mode->x_res;
        var->yres_virtual = (par->ypan) ?
                        info->fix.smem_len / mode->bytes_per_scan_line :
                        mode->y_res;
        var->xoffset = 0;
        var->yoffset = 0;
        var->bits_per_pixel = mode->bits_per_pixel;

        if (var->bits_per_pixel == 15)
                var->bits_per_pixel = 16;

        if (var->bits_per_pixel > 8) {
                var->red.offset    = mode->red_off;
                var->red.length    = mode->red_len;
                var->green.offset  = mode->green_off;
                var->green.length  = mode->green_len;
                var->blue.offset   = mode->blue_off;
                var->blue.length   = mode->blue_len;
                var->transp.offset = mode->rsvd_off;
                var->transp.length = mode->rsvd_len;
        } else {
                var->red.offset    = 0;
                var->green.offset  = 0;
                var->blue.offset   = 0;
                var->transp.offset = 0;

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

static int uvesafb_vbe_find_mode(struct uvesafb_par *par,
                int xres, int yres, int depth, unsigned char flags)
{
        int i, match = -1, h = 0, d = 0x7fffffff;

        for (i = 0; i < par->vbe_modes_cnt; i++) {
                h = abs(par->vbe_modes[i].x_res - xres) +
                    abs(par->vbe_modes[i].y_res - yres) +
                    abs(depth - par->vbe_modes[i].depth);

                /*
                 * We have an exact match in terms of resolution
                 * and depth.
                 */
                if (h == 0)
                        return i;

                if (h < d || (h == d && par->vbe_modes[i].depth > depth)) {
                        d = h;
                        match = i;
                }
        }
        i = 1;

        if (flags & UVESAFB_EXACT_DEPTH &&
                        par->vbe_modes[match].depth != depth)
                i = 0;

        if (flags & UVESAFB_EXACT_RES && d > 24)
                i = 0;

        if (i != 0)
                return match;
        else
                return -1;
}

static u8 *uvesafb_vbe_state_save(struct uvesafb_par *par)
{
        struct uvesafb_ktask *task;
        u8 *state;
        int err;

        if (!par->vbe_state_size)
                return NULL;

        state = kmalloc(par->vbe_state_size, GFP_KERNEL);
        if (!state)
                return ERR_PTR(-ENOMEM);

        task = uvesafb_prep();
        if (!task) {
                kfree(state);
                return NULL;
        }

        task->t.regs.eax = 0x4f04;
        task->t.regs.ecx = 0x000f;
        task->t.regs.edx = 0x0001;
        task->t.flags = TF_BUF_RET | TF_BUF_ESBX;
        task->t.buf_len = par->vbe_state_size;
        task->buf = state;
        err = uvesafb_exec(task);

        if (err || (task->t.regs.eax & 0xffff) != 0x004f) {
                pr_warn("VBE get state call failed (eax=0x%x, err=%d)\n",
                        task->t.regs.eax, err);
                kfree(state);
                state = NULL;
        }

        uvesafb_free(task);
        return state;
}

static void uvesafb_vbe_state_restore(struct uvesafb_par *par, u8 *state_buf)
{
        struct uvesafb_ktask *task;
        int err;

        if (!state_buf)
                return;

        task = uvesafb_prep();
        if (!task)
                return;

        task->t.regs.eax = 0x4f04;
        task->t.regs.ecx = 0x000f;
        task->t.regs.edx = 0x0002;
        task->t.buf_len = par->vbe_state_size;
        task->t.flags = TF_BUF_ESBX;
        task->buf = state_buf;

        err = uvesafb_exec(task);
        if (err || (task->t.regs.eax & 0xffff) != 0x004f)
                pr_warn("VBE state restore call failed (eax=0x%x, err=%d)\n",
                        task->t.regs.eax, err);

        uvesafb_free(task);
}

static int uvesafb_vbe_getinfo(struct uvesafb_ktask *task,
                               struct uvesafb_par *par)
{
        int err;

        task->t.regs.eax = 0x4f00;
        task->t.flags = TF_VBEIB;
        task->t.buf_len = sizeof(struct vbe_ib);
        task->buf = &par->vbe_ib;
        memcpy(par->vbe_ib.vbe_signature, "VBE2", 4);

        err = uvesafb_exec(task);
        if (err || (task->t.regs.eax & 0xffff) != 0x004f) {
                pr_err("Getting VBE info block failed (eax=0x%x, err=%d)\n",
                       (u32)task->t.regs.eax, err);
                return -EINVAL;
        }

        if (par->vbe_ib.vbe_version < 0x0200) {
                pr_err("Sorry, pre-VBE 2.0 cards are not supported\n");
                return -EINVAL;
        }

        if (!par->vbe_ib.mode_list_ptr) {
                pr_err("Missing mode list!\n");
                return -EINVAL;
        }

        pr_info("");

        /*
         * Convert string pointers and the mode list pointer into
         * usable addresses. Print informational messages about the
         * video adapter and its vendor.
         */
        if (par->vbe_ib.oem_vendor_name_ptr)
                pr_cont("%s, ",
                        ((char *)task->buf) + par->vbe_ib.oem_vendor_name_ptr);

        if (par->vbe_ib.oem_product_name_ptr)
                pr_cont("%s, ",
                        ((char *)task->buf) + par->vbe_ib.oem_product_name_ptr);

        if (par->vbe_ib.oem_product_rev_ptr)
                pr_cont("%s, ",
                        ((char *)task->buf) + par->vbe_ib.oem_product_rev_ptr);

        if (par->vbe_ib.oem_string_ptr)
                pr_cont("OEM: %s, ",
                        ((char *)task->buf) + par->vbe_ib.oem_string_ptr);

        pr_cont("VBE v%d.%d\n",
                (par->vbe_ib.vbe_version & 0xff00) >> 8,
                par->vbe_ib.vbe_version & 0xff);

        return 0;
}

static int uvesafb_vbe_getmodes(struct uvesafb_ktask *task,
                                struct uvesafb_par *par)
{
        int off = 0, err;
        u16 *mode;

        par->vbe_modes_cnt = 0;

        /* Count available modes. */
        mode = (u16 *) (((u8 *)&par->vbe_ib) + par->vbe_ib.mode_list_ptr);
        while (*mode != 0xffff) {
                par->vbe_modes_cnt++;
                mode++;
        }

        par->vbe_modes = kzalloc_objs(struct vbe_mode_ib, par->vbe_modes_cnt);
        if (!par->vbe_modes)
                return -ENOMEM;

        /* Get info about all available modes. */
        mode = (u16 *) (((u8 *)&par->vbe_ib) + par->vbe_ib.mode_list_ptr);
        while (*mode != 0xffff) {
                struct vbe_mode_ib *mib;

                uvesafb_reset(task);
                task->t.regs.eax = 0x4f01;
                task->t.regs.ecx = (u32) *mode;
                task->t.flags = TF_BUF_RET | TF_BUF_ESDI;
                task->t.buf_len = sizeof(struct vbe_mode_ib);
                task->buf = par->vbe_modes + off;

                err = uvesafb_exec(task);
                if (err || (task->t.regs.eax & 0xffff) != 0x004f) {
                        pr_warn("Getting mode info block for mode 0x%x failed (eax=0x%x, err=%d)\n",
                                *mode, (u32)task->t.regs.eax, err);
                        mode++;
                        par->vbe_modes_cnt--;
                        continue;
                }

                mib = task->buf;
                mib->mode_id = *mode;

                /*
                 * We only want modes that are supported with the current
                 * hardware configuration, color, graphics and that have
                 * support for the LFB.
                 */
                if ((mib->mode_attr & VBE_MODE_MASK) == VBE_MODE_MASK &&
                                 mib->bits_per_pixel >= 8)
                        off++;
                else
                        par->vbe_modes_cnt--;

                mode++;
                mib->depth = mib->red_len + mib->green_len + mib->blue_len;

                /*
                 * Handle 8bpp modes and modes with broken color component
                 * lengths.
                 */
                if (mib->depth == 0 || (mib->depth == 24 &&
                                        mib->bits_per_pixel == 32))
                        mib->depth = mib->bits_per_pixel;
        }

        if (par->vbe_modes_cnt > 0)
                return 0;
        else
                return -EINVAL;
}

/*
 * The Protected Mode Interface is 32-bit x86 code, so we only run it on
 * x86 and not x86_64.
 */
#ifdef CONFIG_X86_32
static int uvesafb_vbe_getpmi(struct uvesafb_ktask *task,
                              struct uvesafb_par *par)
{
        int i, err;

        uvesafb_reset(task);
        task->t.regs.eax = 0x4f0a;
        task->t.regs.ebx = 0x0;
        err = uvesafb_exec(task);
        if (err)
                return err;

        if ((task->t.regs.eax & 0xffff) != 0x4f || task->t.regs.es < 0xc000) {
                par->pmi_setpal = par->ypan = 0;
        } else {
                par->pmi_base = (u16 *)phys_to_virt(((u32)task->t.regs.es << 4)
                                                + task->t.regs.edi);
                par->pmi_start = (u8 *)par->pmi_base + par->pmi_base[1];
                par->pmi_pal = (u8 *)par->pmi_base + par->pmi_base[2];
                pr_info("protected mode interface info at %04x:%04x\n",
                        (u16)task->t.regs.es, (u16)task->t.regs.edi);
                pr_info("pmi: set display start = %p, set palette = %p\n",
                        par->pmi_start, par->pmi_pal);

                if (par->pmi_base[3]) {
                        pr_info("pmi: ports =");
                        for (i = par->pmi_base[3]/2;
                                        par->pmi_base[i] != 0xffff; i++)
                                pr_cont(" %x", par->pmi_base[i]);
                        pr_cont("\n");

                        if (par->pmi_base[i] != 0xffff) {
                                pr_info("can't handle memory requests, pmi disabled\n");
                                par->ypan = par->pmi_setpal = 0;
                        }
                }
        }
        return 0;
}
#endif /* CONFIG_X86_32 */

/*
 * Check whether a video mode is supported by the Video BIOS and is
 * compatible with the monitor limits.
 */
static int uvesafb_is_valid_mode(struct fb_videomode *mode,
                                 struct fb_info *info)
{
        if (info->monspecs.gtf) {
                fb_videomode_to_var(&info->var, mode);
                if (fb_validate_mode(&info->var, info))
                        return 0;
        }

        if (uvesafb_vbe_find_mode(info->par, mode->xres, mode->yres, 8,
                                UVESAFB_EXACT_RES) == -1)
                return 0;

        return 1;
}

static int uvesafb_vbe_getedid(struct uvesafb_ktask *task, struct fb_info *info)
{
        struct uvesafb_par *par = info->par;
        int err = 0;

        if (noedid || par->vbe_ib.vbe_version < 0x0300)
                return -EINVAL;

        task->t.regs.eax = 0x4f15;
        task->t.regs.ebx = 0;
        task->t.regs.ecx = 0;
        task->t.buf_len = 0;
        task->t.flags = 0;

        err = uvesafb_exec(task);

        if ((task->t.regs.eax & 0xffff) != 0x004f || err)
                return -EINVAL;

        if ((task->t.regs.ebx & 0x3) == 3) {
                pr_info("VBIOS/hardware supports both DDC1 and DDC2 transfers\n");
        } else if ((task->t.regs.ebx & 0x3) == 2) {
                pr_info("VBIOS/hardware supports DDC2 transfers\n");
        } else if ((task->t.regs.ebx & 0x3) == 1) {
                pr_info("VBIOS/hardware supports DDC1 transfers\n");
        } else {
                pr_info("VBIOS/hardware doesn't support DDC transfers\n");
                return -EINVAL;
        }

        task->t.regs.eax = 0x4f15;
        task->t.regs.ebx = 1;
        task->t.regs.ecx = task->t.regs.edx = 0;
        task->t.flags = TF_BUF_RET | TF_BUF_ESDI;
        task->t.buf_len = EDID_LENGTH;
        task->buf = kzalloc(EDID_LENGTH, GFP_KERNEL);
        if (!task->buf)
                return -ENOMEM;

        err = uvesafb_exec(task);

        if ((task->t.regs.eax & 0xffff) == 0x004f && !err) {
                fb_edid_to_monspecs(task->buf, &info->monspecs);

                if (info->monspecs.vfmax && info->monspecs.hfmax) {
                        /*
                         * If the maximum pixel clock wasn't specified in
                         * the EDID block, set it to 300 MHz.
                         */
                        if (info->monspecs.dclkmax == 0)
                                info->monspecs.dclkmax = 300 * 1000000;
                        info->monspecs.gtf = 1;
                }
        } else {
                err = -EINVAL;
        }

        kfree(task->buf);
        return err;
}

static void uvesafb_vbe_getmonspecs(struct uvesafb_ktask *task,
                                    struct fb_info *info)
{
        struct uvesafb_par *par = info->par;
        int i;

        memset(&info->monspecs, 0, sizeof(info->monspecs));

        /*
         * If we don't get all necessary data from the EDID block,
         * mark it as incompatible with the GTF and set nocrtc so
         * that we always use the default BIOS refresh rate.
         */
        if (uvesafb_vbe_getedid(task, info)) {
                info->monspecs.gtf = 0;
                par->nocrtc = 1;
        }

        /* Kernel command line overrides. */
        if (maxclk)
                info->monspecs.dclkmax = maxclk * 1000000;
        if (maxvf)
                info->monspecs.vfmax = maxvf;
        if (maxhf)
                info->monspecs.hfmax = maxhf * 1000;

        /*
         * In case DDC transfers are not supported, the user can provide
         * monitor limits manually. Lower limits are set to "safe" values.
         */
        if (info->monspecs.gtf == 0 && maxclk && maxvf && maxhf) {
                info->monspecs.dclkmin = 0;
                info->monspecs.vfmin = 60;
                info->monspecs.hfmin = 29000;
                info->monspecs.gtf = 1;
                par->nocrtc = 0;
        }

        if (info->monspecs.gtf)
                pr_info("monitor limits: vf = %d Hz, hf = %d kHz, clk = %d MHz\n",
                        info->monspecs.vfmax,
                        (int)(info->monspecs.hfmax / 1000),
                        (int)(info->monspecs.dclkmax / 1000000));
        else
                pr_info("no monitor limits have been set, default refresh rate will be used\n");

        /* Add VBE modes to the modelist. */
        for (i = 0; i < par->vbe_modes_cnt; i++) {
                struct fb_var_screeninfo var;
                struct vbe_mode_ib *mode;
                struct fb_videomode vmode;

                mode = &par->vbe_modes[i];
                memset(&var, 0, sizeof(var));

                var.xres = mode->x_res;
                var.yres = mode->y_res;

                fb_get_mode(FB_VSYNCTIMINGS | FB_IGNOREMON, 60, &var, info);
                fb_var_to_videomode(&vmode, &var);
                fb_add_videomode(&vmode, &info->modelist);
        }

        /* Add valid VESA modes to our modelist. */
        for (i = 0; i < VESA_MODEDB_SIZE; i++) {
                if (uvesafb_is_valid_mode((struct fb_videomode *)
                                                &vesa_modes[i], info))
                        fb_add_videomode(&vesa_modes[i], &info->modelist);
        }

        for (i = 0; i < info->monspecs.modedb_len; i++) {
                if (uvesafb_is_valid_mode(&info->monspecs.modedb[i], info))
                        fb_add_videomode(&info->monspecs.modedb[i],
                                        &info->modelist);
        }

        return;
}

static void uvesafb_vbe_getstatesize(struct uvesafb_ktask *task,
                                     struct uvesafb_par *par)
{
        int err;

        uvesafb_reset(task);

        /*
         * Get the VBE state buffer size. We want all available
         * hardware state data (CL = 0x0f).
         */
        task->t.regs.eax = 0x4f04;
        task->t.regs.ecx = 0x000f;
        task->t.regs.edx = 0x0000;
        task->t.flags = 0;

        err = uvesafb_exec(task);

        if (err || (task->t.regs.eax & 0xffff) != 0x004f) {
                pr_warn("VBE state buffer size cannot be determined (eax=0x%x, err=%d)\n",
                        task->t.regs.eax, err);
                par->vbe_state_size = 0;
                return;
        }

        par->vbe_state_size = 64 * (task->t.regs.ebx & 0xffff);
}

static int uvesafb_vbe_init(struct fb_info *info)
{
        struct uvesafb_ktask *task = NULL;
        struct uvesafb_par *par = info->par;
        int err;

        task = uvesafb_prep();
        if (!task)
                return -ENOMEM;

        err = uvesafb_vbe_getinfo(task, par);
        if (err)
                goto out;

        err = uvesafb_vbe_getmodes(task, par);
        if (err)
                goto out;

        par->nocrtc = nocrtc;
#ifdef CONFIG_X86_32
        par->pmi_setpal = pmi_setpal;
        par->ypan = ypan;

        if (par->pmi_setpal || par->ypan) {
                if (__supported_pte_mask & _PAGE_NX) {
                        par->pmi_setpal = par->ypan = 0;
                        pr_warn("NX protection is active, better not use the PMI\n");
                } else {
                        uvesafb_vbe_getpmi(task, par);
                }
        }
#else
        /* The protected mode interface is not available on non-x86. */
        par->pmi_setpal = par->ypan = 0;
#endif

        INIT_LIST_HEAD(&info->modelist);
        uvesafb_vbe_getmonspecs(task, info);
        uvesafb_vbe_getstatesize(task, par);

out:    uvesafb_free(task);
        return err;
}

static int uvesafb_vbe_init_mode(struct fb_info *info)
{
        struct list_head *pos;
        struct fb_modelist *modelist;
        struct fb_videomode *mode;
        struct uvesafb_par *par = info->par;
        int i, modeid;

        /* Has the user requested a specific VESA mode? */
        if (vbemode) {
                for (i = 0; i < par->vbe_modes_cnt; i++) {
                        if (par->vbe_modes[i].mode_id == vbemode) {
                                modeid = i;
                                uvesafb_setup_var(&info->var, info,
                                                &par->vbe_modes[modeid]);
                                fb_get_mode(FB_VSYNCTIMINGS | FB_IGNOREMON, 60,
                                                &info->var, info);
                                /*
                                 * With pixclock set to 0, the default BIOS
                                 * timings will be used in set_par().
                                 */
                                info->var.pixclock = 0;
                                goto gotmode;
                        }
                }
                pr_info("requested VBE mode 0x%x is unavailable\n", vbemode);
                vbemode = 0;
        }

        /* Count the modes in the modelist */
        i = 0;
        list_for_each(pos, &info->modelist)
                i++;

        /*
         * Convert the modelist into a modedb so that we can use it with
         * fb_find_mode().
         */
        mode = kzalloc_objs(*mode, i);
        if (mode) {
                i = 0;
                list_for_each(pos, &info->modelist) {
                        modelist = list_entry(pos, struct fb_modelist, list);
                        mode[i] = modelist->mode;
                        i++;
                }

                if (!mode_option)
                        mode_option = UVESAFB_DEFAULT_MODE;

                i = fb_find_mode(&info->var, info, mode_option, mode, i,
                        NULL, 8);

                kfree(mode);
        }

        /* fb_find_mode() failed */
        if (i == 0) {
                info->var.xres = 640;
                info->var.yres = 480;
                mode = (struct fb_videomode *)
                                fb_find_best_mode(&info->var, &info->modelist);

                if (mode) {
                        fb_videomode_to_var(&info->var, mode);
                } else {
                        modeid = par->vbe_modes[0].mode_id;
                        uvesafb_setup_var(&info->var, info,
                                        &par->vbe_modes[modeid]);
                        fb_get_mode(FB_VSYNCTIMINGS | FB_IGNOREMON, 60,
                                        &info->var, info);

                        goto gotmode;
                }
        }

        /* Look for a matching VBE mode. */
        modeid = uvesafb_vbe_find_mode(par, info->var.xres, info->var.yres,
                        info->var.bits_per_pixel, UVESAFB_EXACT_RES);

        if (modeid == -1)
                return -EINVAL;

        uvesafb_setup_var(&info->var, info, &par->vbe_modes[modeid]);

gotmode:
        /*
         * If we are not VBE3.0+ compliant, we're done -- the BIOS will
         * ignore our timings anyway.
         */
        if (par->vbe_ib.vbe_version < 0x0300 || par->nocrtc)
                fb_get_mode(FB_VSYNCTIMINGS | FB_IGNOREMON, 60,
                                        &info->var, info);

        return modeid;
}

static int uvesafb_setpalette(struct uvesafb_pal_entry *entries, int count,
                int start, struct fb_info *info)
{
        struct uvesafb_ktask *task;
#ifdef CONFIG_X86
        struct uvesafb_par *par = info->par;
        int i = par->mode_idx;
#endif
        int err = 0;

        /*
         * We support palette modifications for 8 bpp modes only, so
         * there can never be more than 256 entries.
         */
        if (start + count > 256)
                return -EINVAL;

#ifdef CONFIG_X86
        /* Use VGA registers if mode is VGA-compatible. */
        if (i >= 0 && i < par->vbe_modes_cnt &&
            par->vbe_modes[i].mode_attr & VBE_MODE_VGACOMPAT) {
                for (i = 0; i < count; i++) {
                        outb_p(start + i,        dac_reg);
                        outb_p(entries[i].red,   dac_val);
                        outb_p(entries[i].green, dac_val);
                        outb_p(entries[i].blue,  dac_val);
                }
        }
#ifdef CONFIG_X86_32
        else if (par->pmi_setpal) {
                __asm__ __volatile__(
                "call *(%%esi)"
                : /* no return value */
                : "a" (0x4f09),         /* EAX */
                  "b" (0),              /* EBX */
                  "c" (count),          /* ECX */
                  "d" (start),          /* EDX */
                  "D" (entries),        /* EDI */
                  "S" (&par->pmi_pal)); /* ESI */
        }
#endif /* CONFIG_X86_32 */
        else
#endif /* CONFIG_X86 */
        {
                task = uvesafb_prep();
                if (!task)
                        return -ENOMEM;

                task->t.regs.eax = 0x4f09;
                task->t.regs.ebx = 0x0;
                task->t.regs.ecx = count;
                task->t.regs.edx = start;
                task->t.flags = TF_BUF_ESDI;
                task->t.buf_len = sizeof(struct uvesafb_pal_entry) * count;
                task->buf = entries;

                err = uvesafb_exec(task);
                if ((task->t.regs.eax & 0xffff) != 0x004f)
                        err = 1;

                uvesafb_free(task);
        }
        return err;
}

static int uvesafb_setcolreg(unsigned regno, unsigned red, unsigned green,
                unsigned blue, unsigned transp,
                struct fb_info *info)
{
        struct uvesafb_pal_entry entry;
        int shift = 16 - dac_width;
        int err = 0;

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

        if (info->var.bits_per_pixel == 8) {
                entry.red   = red   >> shift;
                entry.green = green >> shift;
                entry.blue  = blue  >> shift;
                entry.pad   = 0;

                err = uvesafb_setpalette(&entry, 1, regno, info);
        } else if (regno < 16) {
                switch (info->var.bits_per_pixel) {
                case 16:
                        if (info->var.red.offset == 10) {
                                /* 1:5:5:5 */
                                ((u32 *) (info->pseudo_palette))[regno] =
                                                ((red   & 0xf800) >>  1) |
                                                ((green & 0xf800) >>  6) |
                                                ((blue  & 0xf800) >> 11);
                        } else {
                                /* 0:5:6:5 */
                                ((u32 *) (info->pseudo_palette))[regno] =
                                                ((red   & 0xf800)      ) |
                                                ((green & 0xfc00) >>  5) |
                                                ((blue  & 0xf800) >> 11);
                        }
                        break;

                case 24:
                case 32:
                        red   >>= 8;
                        green >>= 8;
                        blue  >>= 8;
                        ((u32 *)(info->pseudo_palette))[regno] =
                                (red   << info->var.red.offset)   |
                                (green << info->var.green.offset) |
                                (blue  << info->var.blue.offset);
                        break;
                }
        }
        return err;
}

static int uvesafb_setcmap(struct fb_cmap *cmap, struct fb_info *info)
{
        struct uvesafb_pal_entry *entries;
        int shift = 16 - dac_width;
        int i, err = 0;

        if (info->var.bits_per_pixel == 8) {
                if (cmap->start + cmap->len > info->cmap.start +
                    info->cmap.len || cmap->start < info->cmap.start)
                        return -EINVAL;

                entries = kmalloc_objs(*entries, cmap->len);
                if (!entries)
                        return -ENOMEM;

                for (i = 0; i < cmap->len; i++) {
                        entries[i].red   = cmap->red[i]   >> shift;
                        entries[i].green = cmap->green[i] >> shift;
                        entries[i].blue  = cmap->blue[i]  >> shift;
                        entries[i].pad   = 0;
                }
                err = uvesafb_setpalette(entries, cmap->len, cmap->start, info);
                kfree(entries);
        } else {
                /*
                 * For modes with bpp > 8, we only set the pseudo palette in
                 * the fb_info struct. We rely on uvesafb_setcolreg to do all
                 * sanity checking.
                 */
                for (i = 0; i < cmap->len; i++) {
                        err |= uvesafb_setcolreg(cmap->start + i, cmap->red[i],
                                                cmap->green[i], cmap->blue[i],
                                                0, info);
                }
        }
        return err;
}

static int uvesafb_pan_display(struct fb_var_screeninfo *var,
                struct fb_info *info)
{
#ifdef CONFIG_X86_32
        int offset;
        struct uvesafb_par *par = info->par;

        offset = (var->yoffset * info->fix.line_length + var->xoffset) / 4;

        /*
         * It turns out it's not the best idea to do panning via vm86,
         * so we only allow it if we have a PMI.
         */
        if (par->pmi_start) {
                __asm__ __volatile__(
                        "call *(%%edi)"
                        : /* no return value */
                        : "a" (0x4f07),         /* EAX */
                          "b" (0),              /* EBX */
                          "c" (offset),         /* ECX */
                          "d" (offset >> 16),   /* EDX */
                          "D" (&par->pmi_start));    /* EDI */
        }
#endif
        return 0;
}

static int uvesafb_blank(int blank, struct fb_info *info)
{
        struct uvesafb_ktask *task;
        int err = 1;
#ifdef CONFIG_X86
        struct uvesafb_par *par = info->par;

        if (par->vbe_ib.capabilities & VBE_CAP_VGACOMPAT) {
                int loop = 10000;
                u8 seq = 0, crtc17 = 0;

                if (blank == FB_BLANK_POWERDOWN) {
                        seq = 0x20;
                        crtc17 = 0x00;
                        err = 0;
                } else {
                        seq = 0x00;
                        crtc17 = 0x80;
                        err = (blank == FB_BLANK_UNBLANK) ? 0 : -EINVAL;
                }

                vga_wseq(NULL, 0x00, 0x01);
                seq |= vga_rseq(NULL, 0x01) & ~0x20;
                vga_wseq(NULL, 0x00, seq);

                crtc17 |= vga_rcrt(NULL, 0x17) & ~0x80;
                while (loop--);
                vga_wcrt(NULL, 0x17, crtc17);
                vga_wseq(NULL, 0x00, 0x03);
        } else
#endif /* CONFIG_X86 */
        {
                task = uvesafb_prep();
                if (!task)
                        return -ENOMEM;

                task->t.regs.eax = 0x4f10;
                switch (blank) {
                case FB_BLANK_UNBLANK:
                        task->t.regs.ebx = 0x0001;
                        break;
                case FB_BLANK_NORMAL:
                        task->t.regs.ebx = 0x0101;      /* standby */
                        break;
                case FB_BLANK_POWERDOWN:
                        task->t.regs.ebx = 0x0401;      /* powerdown */
                        break;
                default:
                        goto out;
                }

                err = uvesafb_exec(task);
                if (err || (task->t.regs.eax & 0xffff) != 0x004f)
                        err = 1;
out:            uvesafb_free(task);
        }
        return err;
}

static int uvesafb_open(struct fb_info *info, int user)
{
        struct uvesafb_par *par = info->par;
        int cnt = atomic_read(&par->ref_count);
        u8 *buf = NULL;

        if (!cnt && par->vbe_state_size) {
                buf =  uvesafb_vbe_state_save(par);
                if (IS_ERR(buf)) {
                        pr_warn("save hardware state failed, error code is %ld!\n",
                                PTR_ERR(buf));
                } else {
                        par->vbe_state_orig = buf;
                }
        }

        atomic_inc(&par->ref_count);
        return 0;
}

static int uvesafb_release(struct fb_info *info, int user)
{
        struct uvesafb_ktask *task = NULL;
        struct uvesafb_par *par = info->par;
        int cnt = atomic_read(&par->ref_count);

        if (!cnt)
                return -EINVAL;

        if (cnt != 1)
                goto out;

        task = uvesafb_prep();
        if (!task)
                goto out;

        /* First, try to set the standard 80x25 text mode. */
        task->t.regs.eax = 0x0003;
        uvesafb_exec(task);

        /*
         * Now try to restore whatever hardware state we might have
         * saved when the fb device was first opened.
         */
        uvesafb_vbe_state_restore(par, par->vbe_state_orig);
out:
        atomic_dec(&par->ref_count);
        uvesafb_free(task);
        return 0;
}

static int uvesafb_set_par(struct fb_info *info)
{
        struct uvesafb_par *par = info->par;
        struct uvesafb_ktask *task = NULL;
        struct vbe_crtc_ib *crtc = NULL;
        struct vbe_mode_ib *mode = NULL;
        int i, err = 0, depth = info->var.bits_per_pixel;

        if (depth > 8 && depth != 32)
                depth = info->var.red.length + info->var.green.length +
                        info->var.blue.length;

        i = uvesafb_vbe_find_mode(par, info->var.xres, info->var.yres, depth,
                                 UVESAFB_EXACT_RES | UVESAFB_EXACT_DEPTH);
        if (i >= 0)
                mode = &par->vbe_modes[i];
        else
                return -EINVAL;

        task = uvesafb_prep();
        if (!task)
                return -ENOMEM;
setmode:
        task->t.regs.eax = 0x4f02;
        task->t.regs.ebx = mode->mode_id | 0x4000;      /* use LFB */

        if (par->vbe_ib.vbe_version >= 0x0300 && !par->nocrtc &&
            info->var.pixclock != 0) {
                task->t.regs.ebx |= 0x0800;             /* use CRTC data */
                task->t.flags = TF_BUF_ESDI;
                crtc = kzalloc_obj(struct vbe_crtc_ib);
                if (!crtc) {
                        err = -ENOMEM;
                        goto out;
                }
                crtc->horiz_start = info->var.xres + info->var.right_margin;
                crtc->horiz_end   = crtc->horiz_start + info->var.hsync_len;
                crtc->horiz_total = crtc->horiz_end + info->var.left_margin;

                crtc->vert_start  = info->var.yres + info->var.lower_margin;
                crtc->vert_end    = crtc->vert_start + info->var.vsync_len;
                crtc->vert_total  = crtc->vert_end + info->var.upper_margin;

                crtc->pixel_clock = PICOS2KHZ(info->var.pixclock) * 1000;
                crtc->refresh_rate = (u16)(100 * (crtc->pixel_clock /
                                (crtc->vert_total * crtc->horiz_total)));

                if (info->var.vmode & FB_VMODE_DOUBLE)
                        crtc->flags |= 0x1;
                if (info->var.vmode & FB_VMODE_INTERLACED)
                        crtc->flags |= 0x2;
                if (!(info->var.sync & FB_SYNC_HOR_HIGH_ACT))
                        crtc->flags |= 0x4;
                if (!(info->var.sync & FB_SYNC_VERT_HIGH_ACT))
                        crtc->flags |= 0x8;
                memcpy(&par->crtc, crtc, sizeof(*crtc));
        } else {
                memset(&par->crtc, 0, sizeof(*crtc));
        }

        task->t.buf_len = sizeof(struct vbe_crtc_ib);
        task->buf = &par->crtc;

        err = uvesafb_exec(task);
        if (err || (task->t.regs.eax & 0xffff) != 0x004f) {
                /*
                 * The mode switch might have failed because we tried to
                 * use our own timings.  Try again with the default timings.
                 */
                if (crtc != NULL) {
                        pr_warn("mode switch failed (eax=0x%x, err=%d) - trying again with default timings\n",
                                task->t.regs.eax, err);
                        uvesafb_reset(task);
                        kfree(crtc);
                        crtc = NULL;
                        info->var.pixclock = 0;
                        goto setmode;
                } else {
                        pr_err("mode switch failed (eax=0x%x, err=%d)\n",
                               task->t.regs.eax, err);
                        err = -EINVAL;
                        goto out;
                }
        }
        par->mode_idx = i;

        /* For 8bpp modes, always try to set the DAC to 8 bits. */
        if (par->vbe_ib.capabilities & VBE_CAP_CAN_SWITCH_DAC &&
            mode->bits_per_pixel <= 8) {
                uvesafb_reset(task);
                task->t.regs.eax = 0x4f08;
                task->t.regs.ebx = 0x0800;

                err = uvesafb_exec(task);
                if (err || (task->t.regs.eax & 0xffff) != 0x004f ||
                    ((task->t.regs.ebx & 0xff00) >> 8) != 8) {
                        dac_width = 6;
                } else {
                        dac_width = 8;
                }
        }

        info->fix.visual = (info->var.bits_per_pixel == 8) ?
                                FB_VISUAL_PSEUDOCOLOR : FB_VISUAL_TRUECOLOR;
        info->fix.line_length = mode->bytes_per_scan_line;

out:
        kfree(crtc);
        uvesafb_free(task);

        return err;
}

static void uvesafb_check_limits(struct fb_var_screeninfo *var,
                struct fb_info *info)
{
        const struct fb_videomode *mode;
        struct uvesafb_par *par = info->par;

        /*
         * If pixclock is set to 0, then we're using default BIOS timings
         * and thus don't have to perform any checks here.
         */
        if (!var->pixclock)
                return;

        if (par->vbe_ib.vbe_version < 0x0300) {
                fb_get_mode(FB_VSYNCTIMINGS | FB_IGNOREMON, 60, var, info);
                return;
        }

        if (!fb_validate_mode(var, info))
                return;

        mode = fb_find_best_mode(var, &info->modelist);
        if (mode) {
                if (mode->xres == var->xres && mode->yres == var->yres &&
                    !(mode->vmode & (FB_VMODE_INTERLACED | FB_VMODE_DOUBLE))) {
                        fb_videomode_to_var(var, mode);
                        return;
                }
        }

        if (info->monspecs.gtf && !fb_get_mode(FB_MAXTIMINGS, 0, var, info))
                return;
        /* Use default refresh rate */
        var->pixclock = 0;
}

static int uvesafb_check_var(struct fb_var_screeninfo *var,
                struct fb_info *info)
{
        struct uvesafb_par *par = info->par;
        struct vbe_mode_ib *mode = NULL;
        int match = -1;
        int depth = var->red.length + var->green.length + var->blue.length;

        /*
         * Various apps will use bits_per_pixel to set the color depth,
         * which is theoretically incorrect, but which we'll try to handle
         * here.
         */
        if (depth == 0 || abs(depth - var->bits_per_pixel) >= 8)
                depth = var->bits_per_pixel;

        match = uvesafb_vbe_find_mode(par, var->xres, var->yres, depth,
                                                UVESAFB_EXACT_RES);
        if (match == -1)
                return -EINVAL;

        mode = &par->vbe_modes[match];
        uvesafb_setup_var(var, info, mode);

        /*
         * Check whether we have remapped enough memory for this mode.
         * We might be called at an early stage, when we haven't remapped
         * any memory yet, in which case we simply skip the check.
         */
        if (var->yres * mode->bytes_per_scan_line > info->fix.smem_len
                                                && info->fix.smem_len)
                return -EINVAL;

        if ((var->vmode & FB_VMODE_DOUBLE) &&
                                !(par->vbe_modes[match].mode_attr & 0x100))
                var->vmode &= ~FB_VMODE_DOUBLE;

        if ((var->vmode & FB_VMODE_INTERLACED) &&
                                !(par->vbe_modes[match].mode_attr & 0x200))
                var->vmode &= ~FB_VMODE_INTERLACED;

        uvesafb_check_limits(var, info);

        var->xres_virtual = var->xres;
        var->yres_virtual = (par->ypan) ?
                                info->fix.smem_len / mode->bytes_per_scan_line :
                                var->yres;
        return 0;
}

static struct fb_ops uvesafb_ops = {
        .owner          = THIS_MODULE,
        .fb_open        = uvesafb_open,
        .fb_release     = uvesafb_release,
        FB_DEFAULT_IOMEM_OPS,
        .fb_setcolreg   = uvesafb_setcolreg,
        .fb_setcmap     = uvesafb_setcmap,
        .fb_pan_display = uvesafb_pan_display,
        .fb_blank       = uvesafb_blank,
        .fb_check_var   = uvesafb_check_var,
        .fb_set_par     = uvesafb_set_par,
};

static void uvesafb_init_info(struct fb_info *info, struct vbe_mode_ib *mode)
{
        unsigned int size_vmode;
        unsigned int size_remap;
        unsigned int size_total;
        struct uvesafb_par *par = info->par;
        int i, h;

        info->pseudo_palette = ((u8 *)info->par + sizeof(struct uvesafb_par));
        info->fix = uvesafb_fix;
        info->fix.ypanstep = par->ypan ? 1 : 0;
        info->fix.ywrapstep = (par->ypan > 1) ? 1 : 0;

        /* Disable blanking if the user requested so. */
        if (!blank)
                uvesafb_ops.fb_blank = NULL;

        /*
         * Find out how much IO memory is required for the mode with
         * the highest resolution.
         */
        size_remap = 0;
        for (i = 0; i < par->vbe_modes_cnt; i++) {
                h = par->vbe_modes[i].bytes_per_scan_line *
                                        par->vbe_modes[i].y_res;
                if (h > size_remap)
                        size_remap = h;
        }
        size_remap *= 2;

        /*
         *   size_vmode -- that is the amount of memory needed for the
         *                 used video mode, i.e. the minimum amount of
         *                 memory we need.
         */
        size_vmode = info->var.yres * mode->bytes_per_scan_line;

        /*
         *   size_total -- all video memory we have. Used for mtrr
         *                 entries, resource allocation and bounds
         *                 checking.
         */
        size_total = par->vbe_ib.total_memory * 65536;
        if (vram_total)
                size_total = vram_total * 1024 * 1024;
        if (size_total < size_vmode)
                size_total = size_vmode;

        /*
         *   size_remap -- the amount of video memory we are going to
         *                 use for vesafb.  With modern cards it is no
         *                 option to simply use size_total as th
         *                 wastes plenty of kernel address space.
         */
        if (vram_remap)
                size_remap = vram_remap * 1024 * 1024;
        if (size_remap < size_vmode)
                size_remap = size_vmode;
        if (size_remap > size_total)
                size_remap = size_total;

        info->fix.smem_len = size_remap;
        info->fix.smem_start = mode->phys_base_ptr;

        /*
         * We have to set yres_virtual here because when setup_var() was
         * called, smem_len wasn't defined yet.
         */
        info->var.yres_virtual = info->fix.smem_len /
                                 mode->bytes_per_scan_line;

        if (par->ypan && info->var.yres_virtual > info->var.yres) {
                pr_info("scrolling: %s using protected mode interface, yres_virtual=%d\n",
                        (par->ypan > 1) ? "ywrap" : "ypan",
                        info->var.yres_virtual);
        } else {
                pr_info("scrolling: redraw\n");
                info->var.yres_virtual = info->var.yres;
                par->ypan = 0;
        }

        info->flags = (par->ypan ? FBINFO_HWACCEL_YPAN : 0);

        if (!par->ypan)
                uvesafb_ops.fb_pan_display = NULL;
}

static void uvesafb_init_mtrr(struct fb_info *info)
{
        struct uvesafb_par *par = info->par;

        if (mtrr && !(info->fix.smem_start & (PAGE_SIZE - 1))) {
                int temp_size = info->fix.smem_len;

                int rc;

                /* Find the largest power-of-two */
                temp_size = roundup_pow_of_two(temp_size);

                /* Try and find a power of two to add */
                do {
                        rc = arch_phys_wc_add(info->fix.smem_start, temp_size);
                        temp_size >>= 1;
                } while (temp_size >= PAGE_SIZE && rc == -EINVAL);

                if (rc >= 0)
                        par->mtrr_handle = rc;
        }
}

static void uvesafb_ioremap(struct fb_info *info)
{
        info->screen_base = ioremap_wc(info->fix.smem_start, info->fix.smem_len);
}

static ssize_t uvesafb_show_vbe_ver(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct fb_info *info = dev_get_drvdata(dev);
        struct uvesafb_par *par = info->par;

        return sysfs_emit(buf, "%.4x\n", par->vbe_ib.vbe_version);
}

static DEVICE_ATTR(vbe_version, S_IRUGO, uvesafb_show_vbe_ver, NULL);

static ssize_t uvesafb_show_vbe_modes(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct fb_info *info = dev_get_drvdata(dev);
        struct uvesafb_par *par = info->par;
        int ret = 0, i;

        for (i = 0; i < par->vbe_modes_cnt && ret < PAGE_SIZE; i++) {
                ret += scnprintf(buf + ret, PAGE_SIZE - ret,
                        "%dx%d-%d, 0x%.4x\n",
                        par->vbe_modes[i].x_res, par->vbe_modes[i].y_res,
                        par->vbe_modes[i].depth, par->vbe_modes[i].mode_id);
        }

        return ret;
}

static DEVICE_ATTR(vbe_modes, S_IRUGO, uvesafb_show_vbe_modes, NULL);

static ssize_t uvesafb_show_vendor(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct fb_info *info = dev_get_drvdata(dev);
        struct uvesafb_par *par = info->par;

        if (par->vbe_ib.oem_vendor_name_ptr)
                return sysfs_emit(buf, "%s\n", (char *)
                        (&par->vbe_ib) + par->vbe_ib.oem_vendor_name_ptr);
        else
                return 0;
}

static DEVICE_ATTR(oem_vendor, S_IRUGO, uvesafb_show_vendor, NULL);

static ssize_t uvesafb_show_product_name(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct fb_info *info = dev_get_drvdata(dev);
        struct uvesafb_par *par = info->par;

        if (par->vbe_ib.oem_product_name_ptr)
                return sysfs_emit(buf, "%s\n", (char *)
                        (&par->vbe_ib) + par->vbe_ib.oem_product_name_ptr);
        else
                return 0;
}

static DEVICE_ATTR(oem_product_name, S_IRUGO, uvesafb_show_product_name, NULL);

static ssize_t uvesafb_show_product_rev(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct fb_info *info = dev_get_drvdata(dev);
        struct uvesafb_par *par = info->par;

        if (par->vbe_ib.oem_product_rev_ptr)
                return sysfs_emit(buf, "%s\n", (char *)
                        (&par->vbe_ib) + par->vbe_ib.oem_product_rev_ptr);
        else
                return 0;
}

static DEVICE_ATTR(oem_product_rev, S_IRUGO, uvesafb_show_product_rev, NULL);

static ssize_t uvesafb_show_oem_string(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct fb_info *info = dev_get_drvdata(dev);
        struct uvesafb_par *par = info->par;

        if (par->vbe_ib.oem_string_ptr)
                return sysfs_emit(buf, "%s\n",
                        (char *)(&par->vbe_ib) + par->vbe_ib.oem_string_ptr);
        else
                return 0;
}

static DEVICE_ATTR(oem_string, S_IRUGO, uvesafb_show_oem_string, NULL);

static ssize_t uvesafb_show_nocrtc(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct fb_info *info = dev_get_drvdata(dev);
        struct uvesafb_par *par = info->par;

        return sysfs_emit(buf, "%d\n", par->nocrtc);
}

static ssize_t uvesafb_store_nocrtc(struct device *dev,
                struct device_attribute *attr, const char *buf, size_t count)
{
        struct fb_info *info = dev_get_drvdata(dev);
        struct uvesafb_par *par = info->par;

        if (count > 0) {
                if (buf[0] == '0')
                        par->nocrtc = 0;
                else
                        par->nocrtc = 1;
        }
        return count;
}

static DEVICE_ATTR(nocrtc, S_IRUGO | S_IWUSR, uvesafb_show_nocrtc,
                        uvesafb_store_nocrtc);

static struct attribute *uvesafb_dev_attrs[] = {
        &dev_attr_vbe_version.attr,
        &dev_attr_vbe_modes.attr,
        &dev_attr_oem_vendor.attr,
        &dev_attr_oem_product_name.attr,
        &dev_attr_oem_product_rev.attr,
        &dev_attr_oem_string.attr,
        &dev_attr_nocrtc.attr,
        NULL,
};

static const struct attribute_group uvesafb_dev_attgrp = {
        .name = NULL,
        .attrs = uvesafb_dev_attrs,
};

static int uvesafb_probe(struct platform_device *dev)
{
        struct fb_info *info;
        struct vbe_mode_ib *mode = NULL;
        struct uvesafb_par *par;
        int err = 0, i;

        info = framebuffer_alloc(sizeof(*par) + sizeof(u32) * 256, &dev->dev);
        if (!info)
                return -ENOMEM;

        par = info->par;

        err = uvesafb_vbe_init(info);
        if (err) {
                pr_err("vbe_init() failed with %d\n", err);
                goto out;
        }

        info->fbops = &uvesafb_ops;

        i = uvesafb_vbe_init_mode(info);
        if (i < 0) {
                err = -EINVAL;
                goto out;
        } else {
                mode = &par->vbe_modes[i];
        }

        if (fb_alloc_cmap(&info->cmap, 256, 0) < 0) {
                err = -ENXIO;
                goto out;
        }

        uvesafb_init_info(info, mode);

        if (!request_region(0x3c0, 32, "uvesafb")) {
                pr_err("request region 0x3c0-0x3e0 failed\n");
                err = -EIO;
                goto out_mode;
        }

        if (!request_mem_region(info->fix.smem_start, info->fix.smem_len,
                                "uvesafb")) {
                pr_err("cannot reserve video memory at 0x%lx\n",
                       info->fix.smem_start);
                err = -EIO;
                goto out_reg;
        }

        uvesafb_init_mtrr(info);
        uvesafb_ioremap(info);

        if (!info->screen_base) {
                pr_err("abort, cannot ioremap 0x%x bytes of video memory at 0x%lx\n",
                       info->fix.smem_len, info->fix.smem_start);
                err = -EIO;
                goto out_mem;
        }

        platform_set_drvdata(dev, info);

        if (register_framebuffer(info) < 0) {
                pr_err("failed to register framebuffer device\n");
                err = -EINVAL;
                goto out_unmap;
        }

        pr_info("framebuffer at 0x%lx, mapped to 0x%p, using %dk, total %dk\n",
                info->fix.smem_start, info->screen_base,
                info->fix.smem_len / 1024, par->vbe_ib.total_memory * 64);
        fb_info(info, "%s frame buffer device\n", info->fix.id);

        err = sysfs_create_group(&dev->dev.kobj, &uvesafb_dev_attgrp);
        if (err != 0)
                fb_warn(info, "failed to register attributes\n");

        return 0;

out_unmap:
        iounmap(info->screen_base);
out_mem:
        arch_phys_wc_del(par->mtrr_handle);
        release_mem_region(info->fix.smem_start, info->fix.smem_len);
out_reg:
        release_region(0x3c0, 32);
out_mode:
        if (!list_empty(&info->modelist))
                fb_destroy_modelist(&info->modelist);
        fb_destroy_modedb(info->monspecs.modedb);
        fb_dealloc_cmap(&info->cmap);
out:
        kfree(par->vbe_modes);

        framebuffer_release(info);
        return err;
}

static void uvesafb_remove(struct platform_device *dev)
{
        struct fb_info *info = platform_get_drvdata(dev);
        struct uvesafb_par *par = info->par;

        sysfs_remove_group(&dev->dev.kobj, &uvesafb_dev_attgrp);
        unregister_framebuffer(info);
        release_region(0x3c0, 32);
        iounmap(info->screen_base);
        arch_phys_wc_del(par->mtrr_handle);
        release_mem_region(info->fix.smem_start, info->fix.smem_len);
        fb_destroy_modedb(info->monspecs.modedb);
        fb_dealloc_cmap(&info->cmap);

        kfree(par->vbe_modes);
        kfree(par->vbe_state_orig);
        kfree(par->vbe_state_saved);

        framebuffer_release(info);
}

static struct platform_driver uvesafb_driver = {
        .probe  = uvesafb_probe,
        .remove = uvesafb_remove,
        .driver = {
                .name = "uvesafb",
        },
};

static struct platform_device *uvesafb_device;

#ifndef MODULE
static int uvesafb_setup(char *options)
{
        char *this_opt;

        if (!options || !*options)
                return 0;

        while ((this_opt = strsep(&options, ",")) != NULL) {
                if (!*this_opt) continue;

                if (!strcmp(this_opt, "redraw"))
                        ypan = 0;
                else if (!strcmp(this_opt, "ypan"))
                        ypan = 1;
                else if (!strcmp(this_opt, "ywrap"))
                        ypan = 2;
                else if (!strcmp(this_opt, "vgapal"))
                        pmi_setpal = false;
                else if (!strcmp(this_opt, "pmipal"))
                        pmi_setpal = true;
                else if (!strncmp(this_opt, "mtrr:", 5))
                        mtrr = simple_strtoul(this_opt+5, NULL, 0);
                else if (!strcmp(this_opt, "nomtrr"))
                        mtrr = 0;
                else if (!strcmp(this_opt, "nocrtc"))
                        nocrtc = true;
                else if (!strcmp(this_opt, "noedid"))
                        noedid = true;
                else if (!strcmp(this_opt, "noblank"))
                        blank = false;
                else if (!strncmp(this_opt, "vtotal:", 7))
                        vram_total = simple_strtoul(this_opt + 7, NULL, 0);
                else if (!strncmp(this_opt, "vremap:", 7))
                        vram_remap = simple_strtoul(this_opt + 7, NULL, 0);
                else if (!strncmp(this_opt, "maxhf:", 6))
                        maxhf = simple_strtoul(this_opt + 6, NULL, 0);
                else if (!strncmp(this_opt, "maxvf:", 6))
                        maxvf = simple_strtoul(this_opt + 6, NULL, 0);
                else if (!strncmp(this_opt, "maxclk:", 7))
                        maxclk = simple_strtoul(this_opt + 7, NULL, 0);
                else if (!strncmp(this_opt, "vbemode:", 8))
                        vbemode = simple_strtoul(this_opt + 8, NULL, 0);
                else if (this_opt[0] >= '0' && this_opt[0] <= '9') {
                        mode_option = this_opt;
                } else {
                        pr_warn("unrecognized option %s\n", this_opt);
                }
        }

        if (mtrr != 3 && mtrr != 0)
                pr_warn("uvesafb: mtrr should be set to 0 or 3; %d is unsupported", mtrr);

        return 0;
}
#endif /* !MODULE */

static ssize_t v86d_show(struct device_driver *dev, char *buf)
{
        return snprintf(buf, PAGE_SIZE, "%s\n", v86d_path);
}

static ssize_t v86d_store(struct device_driver *dev, const char *buf,
                size_t count)
{
        strscpy_pad(v86d_path, buf);
        return count;
}
static DRIVER_ATTR_RW(v86d);

static int uvesafb_init(void)
{
        int err;

#ifndef MODULE
        char *option = NULL;

        if (fb_get_options("uvesafb", &option))
                return -ENODEV;
        uvesafb_setup(option);
#endif
        err = cn_add_callback(&uvesafb_cn_id, "uvesafb", uvesafb_cn_callback);
        if (err)
                return err;

        err = platform_driver_register(&uvesafb_driver);

        if (!err) {
                uvesafb_device = platform_device_alloc("uvesafb", 0);
                if (uvesafb_device)
                        err = platform_device_add(uvesafb_device);
                else
                        err = -ENOMEM;

                if (err) {
                        platform_device_put(uvesafb_device);
                        platform_driver_unregister(&uvesafb_driver);
                        cn_del_callback(&uvesafb_cn_id);
                        return err;
                }

                err = driver_create_file(&uvesafb_driver.driver,
                                &driver_attr_v86d);
                if (err) {
                        pr_warn("failed to register attributes\n");
                        err = 0;
                }
        }
        return err;
}

module_init(uvesafb_init);

static void uvesafb_exit(void)
{
        struct uvesafb_ktask *task;

        if (v86d_started) {
                task = uvesafb_prep();
                if (task) {
                        task->t.flags = TF_EXIT;
                        uvesafb_exec(task);
                        uvesafb_free(task);
                }
        }

        driver_remove_file(&uvesafb_driver.driver, &driver_attr_v86d);
        platform_device_unregister(uvesafb_device);
        platform_driver_unregister(&uvesafb_driver);
        cn_del_callback(&uvesafb_cn_id);
}

module_exit(uvesafb_exit);

static int param_set_scroll(const char *val, const struct kernel_param *kp)
{
        ypan = 0;

        if (!strcmp(val, "redraw"))
                ypan = 0;
        else if (!strcmp(val, "ypan"))
                ypan = 1;
        else if (!strcmp(val, "ywrap"))
                ypan = 2;
        else
                return -EINVAL;

        return 0;
}
static const struct kernel_param_ops param_ops_scroll = {
        .set = param_set_scroll,
};
#define param_check_scroll(name, p) __param_check(name, p, void)

module_param_named(scroll, ypan, scroll, 0);
MODULE_PARM_DESC(scroll,
        "Scrolling mode, set to 'redraw', 'ypan', or 'ywrap'");
module_param_named(vgapal, pmi_setpal, invbool, 0);
MODULE_PARM_DESC(vgapal, "Set palette using VGA registers");
module_param_named(pmipal, pmi_setpal, bool, 0);
MODULE_PARM_DESC(pmipal, "Set palette using PMI calls");
module_param(mtrr, uint, 0);
MODULE_PARM_DESC(mtrr,
        "Memory Type Range Registers setting. Use 0 to disable.");
module_param(blank, bool, 0);
MODULE_PARM_DESC(blank, "Enable hardware blanking");
module_param(nocrtc, bool, 0);
MODULE_PARM_DESC(nocrtc, "Ignore CRTC timings when setting modes");
module_param(noedid, bool, 0);
MODULE_PARM_DESC(noedid,
        "Ignore EDID-provided monitor limits when setting modes");
module_param(vram_remap, uint, 0);
MODULE_PARM_DESC(vram_remap, "Set amount of video memory to be used [MiB]");
module_param(vram_total, uint, 0);
MODULE_PARM_DESC(vram_total, "Set total amount of video memory [MiB]");
module_param(maxclk, ushort, 0);
MODULE_PARM_DESC(maxclk, "Maximum pixelclock [MHz], overrides EDID data");
module_param(maxhf, ushort, 0);
MODULE_PARM_DESC(maxhf,
        "Maximum horizontal frequency [kHz], overrides EDID data");
module_param(maxvf, ushort, 0);
MODULE_PARM_DESC(maxvf,
        "Maximum vertical frequency [Hz], overrides EDID data");
module_param(mode_option, charp, 0);
MODULE_PARM_DESC(mode_option,
        "Specify initial video mode as \"<xres>x<yres>[-<bpp>][@<refresh>]\"");
module_param(vbemode, ushort, 0);
MODULE_PARM_DESC(vbemode,
        "VBE mode number to set, overrides the 'mode' option");
module_param_string(v86d, v86d_path, PATH_MAX, 0660);
MODULE_PARM_DESC(v86d, "Path to the v86d userspace helper.");

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Michal Januszewski <spock@gentoo.org>");
MODULE_DESCRIPTION("Framebuffer driver for VBE2.0+ compliant graphics boards");