firmware: coreboot: Add coreboot framebuffer driver

Register a simplefb framebuffer when the coreboot table contains a
framebuffer entry.

Signed-off-by: Samuel Holland <samuel@sholland.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Samuel Holland 2018-01-24 19:41:20 -06:00 committed by Greg Kroah-Hartman
parent b616cf53aa
commit 851b4c1453
4 changed files with 146 additions and 0 deletions

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@ -55,6 +55,14 @@ config GOOGLE_MEMCONSOLE_X86_LEGACY
the EBDA on Google servers. If found, this log is exported to
userland in the file /sys/firmware/log.
config GOOGLE_FRAMEBUFFER_COREBOOT
tristate "Coreboot Framebuffer"
depends on FB_SIMPLE
depends on GOOGLE_COREBOOT_TABLE
help
This option enables the kernel to search for a framebuffer in
the coreboot table. If found, it is registered with simplefb.
config GOOGLE_MEMCONSOLE_COREBOOT
tristate "Firmware Memory Console"
depends on GOOGLE_COREBOOT_TABLE

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@ -4,6 +4,7 @@ obj-$(CONFIG_GOOGLE_SMI) += gsmi.o
obj-$(CONFIG_GOOGLE_COREBOOT_TABLE) += coreboot_table.o
obj-$(CONFIG_GOOGLE_COREBOOT_TABLE_ACPI) += coreboot_table-acpi.o
obj-$(CONFIG_GOOGLE_COREBOOT_TABLE_OF) += coreboot_table-of.o
obj-$(CONFIG_GOOGLE_FRAMEBUFFER_COREBOOT) += framebuffer-coreboot.o
obj-$(CONFIG_GOOGLE_MEMCONSOLE) += memconsole.o
obj-$(CONFIG_GOOGLE_MEMCONSOLE_COREBOOT) += memconsole-coreboot.o
obj-$(CONFIG_GOOGLE_MEMCONSOLE_X86_LEGACY) += memconsole-x86-legacy.o

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@ -3,6 +3,7 @@
*
* Internal header for coreboot table access.
*
* Copyright 2014 Gerd Hoffmann <kraxel@redhat.com>
* Copyright 2017 Google Inc.
* Copyright 2017 Samuel Holland <samuel@sholland.org>
*
@ -46,12 +47,33 @@ struct lb_cbmem_ref {
u64 cbmem_addr;
};
/* Describes framebuffer setup by coreboot */
struct lb_framebuffer {
u32 tag;
u32 size;
u64 physical_address;
u32 x_resolution;
u32 y_resolution;
u32 bytes_per_line;
u8 bits_per_pixel;
u8 red_mask_pos;
u8 red_mask_size;
u8 green_mask_pos;
u8 green_mask_size;
u8 blue_mask_pos;
u8 blue_mask_size;
u8 reserved_mask_pos;
u8 reserved_mask_size;
};
/* A device, additionally with information from coreboot. */
struct coreboot_device {
struct device dev;
union {
struct coreboot_table_entry entry;
struct lb_cbmem_ref cbmem_ref;
struct lb_framebuffer framebuffer;
};
};

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@ -0,0 +1,115 @@
/*
* framebuffer-coreboot.c
*
* Memory based framebuffer accessed through coreboot table.
*
* Copyright 2012-2013 David Herrmann <dh.herrmann@gmail.com>
* Copyright 2017 Google Inc.
* Copyright 2017 Samuel Holland <samuel@sholland.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License v2.0 as published by
* the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/platform_data/simplefb.h>
#include <linux/platform_device.h>
#include "coreboot_table.h"
#define CB_TAG_FRAMEBUFFER 0x12
static const struct simplefb_format formats[] = SIMPLEFB_FORMATS;
static int framebuffer_probe(struct coreboot_device *dev)
{
int i;
u32 length;
struct lb_framebuffer *fb = &dev->framebuffer;
struct platform_device *pdev;
struct resource res;
struct simplefb_platform_data pdata = {
.width = fb->x_resolution,
.height = fb->y_resolution,
.stride = fb->bytes_per_line,
.format = NULL,
};
for (i = 0; i < ARRAY_SIZE(formats); ++i) {
if (fb->bits_per_pixel == formats[i].bits_per_pixel &&
fb->red_mask_pos == formats[i].red.offset &&
fb->red_mask_size == formats[i].red.length &&
fb->green_mask_pos == formats[i].green.offset &&
fb->green_mask_size == formats[i].green.length &&
fb->blue_mask_pos == formats[i].blue.offset &&
fb->blue_mask_size == formats[i].blue.length &&
fb->reserved_mask_pos == formats[i].transp.offset &&
fb->reserved_mask_size == formats[i].transp.length)
pdata.format = formats[i].name;
}
if (!pdata.format)
return -ENODEV;
memset(&res, 0, sizeof(res));
res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
res.name = "Coreboot Framebuffer";
res.start = fb->physical_address;
length = PAGE_ALIGN(fb->y_resolution * fb->bytes_per_line);
res.end = res.start + length - 1;
if (res.end <= res.start)
return -EINVAL;
pdev = platform_device_register_resndata(&dev->dev,
"simple-framebuffer", 0,
&res, 1, &pdata,
sizeof(pdata));
if (IS_ERR(pdev))
pr_warn("coreboot: could not register framebuffer\n");
else
dev_set_drvdata(&dev->dev, pdev);
return PTR_ERR_OR_ZERO(pdev);
}
static int framebuffer_remove(struct coreboot_device *dev)
{
struct platform_device *pdev = dev_get_drvdata(&dev->dev);
platform_device_unregister(pdev);
return 0;
}
static struct coreboot_driver framebuffer_driver = {
.probe = framebuffer_probe,
.remove = framebuffer_remove,
.drv = {
.name = "framebuffer",
},
.tag = CB_TAG_FRAMEBUFFER,
};
static int __init coreboot_framebuffer_init(void)
{
return coreboot_driver_register(&framebuffer_driver);
}
static void coreboot_framebuffer_exit(void)
{
coreboot_driver_unregister(&framebuffer_driver);
}
module_init(coreboot_framebuffer_init);
module_exit(coreboot_framebuffer_exit);
MODULE_AUTHOR("Samuel Holland <samuel@sholland.org>");
MODULE_LICENSE("GPL");