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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Generic System Framebuffers on x86
* Copyright (c) 2012-2013 David Herrmann <dh.herrmann@gmail.com>
*/
/*
* simple-framebuffer probing
* Try to convert "screen_info" into a "simple-framebuffer" compatible mode.
* If the mode is incompatible, we return "false" and let the caller create
* legacy nodes instead.
*/
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/platform_data/simplefb.h>
#include <linux/platform_device.h>
#include <linux/screen_info.h>
#include <asm/sysfb.h>
static const char simplefb_resname[] = "BOOTFB";
static const struct simplefb_format formats[] = SIMPLEFB_FORMATS;
/* try parsing x86 screen_info into a simple-framebuffer mode struct */
__init bool parse_mode(const struct screen_info *si,
struct simplefb_platform_data *mode)
{
const struct simplefb_format *f;
__u8 type;
unsigned int i;
type = si->orig_video_isVGA;
if (type != VIDEO_TYPE_VLFB && type != VIDEO_TYPE_EFI)
return false;
for (i = 0; i < ARRAY_SIZE(formats); ++i) {
f = &formats[i];
if (si->lfb_depth == f->bits_per_pixel &&
si->red_size == f->red.length &&
si->red_pos == f->red.offset &&
si->green_size == f->green.length &&
si->green_pos == f->green.offset &&
si->blue_size == f->blue.length &&
si->blue_pos == f->blue.offset &&
si->rsvd_size == f->transp.length &&
si->rsvd_pos == f->transp.offset) {
mode->format = f->name;
mode->width = si->lfb_width;
mode->height = si->lfb_height;
mode->stride = si->lfb_linelength;
return true;
}
}
return false;
}
__init int create_simplefb(const struct screen_info *si,
const struct simplefb_platform_data *mode)
{
struct platform_device *pd;
struct resource res;
u64 base, size;
u32 length;
/*
* If the 64BIT_BASE capability is set, ext_lfb_base will contain the
* upper half of the base address. Assemble the address, then make sure
* it is valid and we can actually access it.
*/
base = si->lfb_base;
if (si->capabilities & VIDEO_CAPABILITY_64BIT_BASE)
base |= (u64)si->ext_lfb_base << 32;
if (!base || (u64)(resource_size_t)base != base) {
printk(KERN_DEBUG "sysfb: inaccessible VRAM base\n");
return -EINVAL;
}
/*
* Don't use lfb_size as IORESOURCE size, since it may contain the
* entire VMEM, and thus require huge mappings. Use just the part we
* need, that is, the part where the framebuffer is located. But verify
* that it does not exceed the advertised VMEM.
* Note that in case of VBE, the lfb_size is shifted by 16 bits for
* historical reasons.
*/
size = si->lfb_size;
if (si->orig_video_isVGA == VIDEO_TYPE_VLFB)
size <<= 16;
length = mode->height * mode->stride;
length = PAGE_ALIGN(length);
if (length > size) {
printk(KERN_WARNING "sysfb: VRAM smaller than advertised\n");
return -EINVAL;
}
/* setup IORESOURCE_MEM as framebuffer memory */
memset(&res, 0, sizeof(res));
res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
res.name = simplefb_resname;
res.start = base;
res.end = res.start + length - 1;
if (res.end <= res.start)
return -EINVAL;
pd = platform_device_register_resndata(NULL, "simple-framebuffer", 0,
&res, 1, mode, sizeof(*mode));
return PTR_ERR_OR_ZERO(pd);
}
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