linux/arch/x86/kernel/sysfb_simplefb.c
David Herrmann 29d274b8d3 x86/simplefb: Mark framebuffer mem-resources as IORESOURCE_BUSY to avoid bootup warning
IORESOURCE_BUSY is used to mark temporary driver mem-resources
instead of global regions. This suppresses warnings if regions
overlap with a region marked as BUSY.

This was always the case for VESA/VGA/EFI framebuffer regions so
do the same for simplefb regions. The reason we do this is to
allow device handover to real GPU drivers like
i915/radeon/nouveau which get the same regions via PCI BARs.

Maybe at some point we will be able to unregister platform
devices properly during the handover. In this case the simplefb
region would get removed before the new region is created.
However, this is currently not the case and would require rather
huge changes in remove_conflicting_framebuffers(). Add the BUSY
marker now and try to eventually rewrite the handover for a next release.

Also see kernel/resource.c for more information:

  /*
   * if a resource is "BUSY", it's not a hardware resource
   * but a driver mapping of such a resource; we don't want
   * to warn for those; some drivers legitimately map only
   * partial hardware resources. (example: vesafb)
   */

This suppresses warnings like:

  ------------[ cut here ]------------
  WARNING: CPU: 2 PID: 199 at arch/x86/mm/ioremap.c:171 __ioremap_caller+0x2e3/0x390()
  Info: mapping multiple BARs. Your kernel is fine.
  Call Trace:
    dump_stack+0x54/0x8d
    warn_slowpath_common+0x7d/0xa0
    warn_slowpath_fmt+0x4c/0x50
    iomem_map_sanity_check+0xac/0xe0
    __ioremap_caller+0x2e3/0x390
    ioremap_wc+0x32/0x40
    i915_driver_load+0x670/0xf50 [i915]
    ...

Reported-by: Tom Gundersen <teg@jklm.no>
Tested-by: Tom Gundersen <teg@jklm.no>
Tested-by: Pavel Roskin <proski@gnu.org>
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Link: http://lkml.kernel.org/r/1380724864-1757-1-git-send-email-dh.herrmann@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-03 07:51:11 +02:00

96 lines
2.7 KiB
C

/*
* Generic System Framebuffers on x86
* Copyright (c) 2012-2013 David Herrmann <dh.herrmann@gmail.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*/
/*
* 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;
unsigned long len;
/* don't use lfb_size as it may contain the whole VMEM instead of only
* the part that is occupied by the framebuffer */
len = mode->height * mode->stride;
len = PAGE_ALIGN(len);
if (len > (u64)si->lfb_size << 16) {
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 = si->lfb_base;
res.end = si->lfb_base + len - 1;
if (res.end <= res.start)
return -EINVAL;
pd = platform_device_register_resndata(NULL, "simple-framebuffer", 0,
&res, 1, mode, sizeof(*mode));
if (IS_ERR(pd))
return PTR_ERR(pd);
return 0;
}