path: root/drivers/staging/udlfb/udlfb.c

/*****************************************************************************
 *                          DLFB Kernel Driver                               *
 *                            Version 0.2 (udlfb)                            *
 *             (C) 2009 Roberto De Ioris <roberto@unbit.it>                  *
 *                                                                           *
 *     This file is licensed under the GPLv2. See COPYING in the package.    *
 * Based on the amazing work of Florian Echtler and libdlo 0.1               *
 *                                                                           *
 *                                                                           *
 * 10.06.09 release 0.2.3 (edid ioctl, fallback for unsupported modes)       *
 * 05.06.09 release 0.2.2 (real screen blanking, rle compression, double buffer) *
 * 31.05.09 release 0.2                                                      *
 * 22.05.09 First public (ugly) release                                      *
 *****************************************************************************/

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/usb.h>
#include <linux/uaccess.h>
#include <linux/mm.h>
#include <linux/fb.h>
#include <linux/mutex.h>
#include <linux/vmalloc.h>

#include "udlfb.h"

#define DRIVER_VERSION "DLFB 0.2"

/* memory functions taken from vfb */

static void *rvmalloc(unsigned long size)
{
	void *mem;
	unsigned long adr;

	size = PAGE_ALIGN(size);
	mem = vmalloc_32(size);
	if (!mem)
		return NULL;

	memset(mem, 0, size);	/* Clear the ram out, no junk to the user */
	adr = (unsigned long)mem;
	while (size > 0) {
		SetPageReserved(vmalloc_to_page((void *)adr));
		adr += PAGE_SIZE;
		size -= PAGE_SIZE;
	}

	return mem;
}

static void rvfree(void *mem, unsigned long size)
{
	unsigned long adr;

	if (!mem)
		return;

	adr = (unsigned long)mem;
	while ((long)size > 0) {
		ClearPageReserved(vmalloc_to_page((void *)adr));
		adr += PAGE_SIZE;
		size -= PAGE_SIZE;
	}
	vfree(mem);
}

static int dlfb_mmap(struct fb_info *info, struct vm_area_struct *vma)
{
	unsigned long start = vma->vm_start;
	unsigned long size = vma->vm_end - vma->vm_start;
	unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
	unsigned long page, pos;

	printk("MMAP: %lu %u\n", offset + size, info->fix.smem_len);

	if (offset + size > info->fix.smem_len)
		return -EINVAL;

	pos = (unsigned long)info->fix.smem_start + offset;

	while (size > 0) {
		page = vmalloc_to_pfn((void *)pos);
		if (remap_pfn_range(vma, start, page, PAGE_SIZE, PAGE_SHARED))
			return -EAGAIN;

		start += PAGE_SIZE;
		pos += PAGE_SIZE;
		if (size > PAGE_SIZE)
			size -= PAGE_SIZE;
		else
			size = 0;
	}

	vma->vm_flags |= VM_RESERVED;	/* avoid to swap out this VMA */
	return 0;

}

/* ioctl structure */
struct dloarea {
	int x, y;
	int w, h;
	int x2, y2;
};

/*
static struct usb_device_id id_table [] = {
	{ USB_DEVICE(0x17e9, 0x023d) },
	{ }
};
*/

static struct usb_device_id id_table[] = {
	{.idVendor = 0x17e9, .match_flags = USB_DEVICE_ID_MATCH_VENDOR,},
	{},
};
MODULE_DEVICE_TABLE(usb, id_table);

static struct usb_driver dlfb_driver;

// thanks to Henrik Bjerregaard Pedersen for this function
static char *rle_compress16(uint16_t * src, char *dst, int rem)
{

	int rl;
	uint16_t pix0;
	char *end_if_raw = dst + 6 + 2 * rem;

	dst += 6;		// header will be filled in if RLE is worth it

	while (rem && dst < end_if_raw) {
		char *start = (char *)src;

		pix0 = *src++;
		rl = 1;
		rem--;
		while (rem && *src == pix0)
			rem--, rl++, src++;
		*dst++ = rl;
		*dst++ = start[1];
		*dst++ = start[0];
	}

	return dst;
}

/*
Thanks to Henrik Bjerregaard Pedersen for rle implementation and code refactoring.
Next step is huffman compression.
*/

static int
image_blit(struct dlfb_data *dev_info, int x, int y, int width, int height,
	   char *data)
{

	int i, j, base;
	int rem = width;
	int ret;

	int firstdiff, thistime;

	char *bufptr;

	if (x + width > dev_info->info->var.xres)
		return -EINVAL;

	if (y + height > dev_info->info->var.yres)
		return -EINVAL;

	mutex_lock(&