ACPI: Add support for exposing BGRT data

What:		/sys/firmware/acpi/bgrt/

Date:		January 2012

Contact:	Matthew Garrett <mjg@redhat.com>

Description:

		The BGRT is an ACPI 5.0 feature that allows the OS

		to obtain a copy of the firmware boot splash and

		some associated metadata. This is intended to be used

		by boot splash applications in order to interact with

		the firmware boot splash in order to avoid jarring

		transitions.

		image: The image bitmap. Currently a 32-bit BMP.

		status: 1 if the image is valid, 0 if firmware invalidated it.

		type: 0 indicates image is in BMP format.

		version: The version of the BGRT. Currently 1.

		xoffset: The number of pixels between the left of the screen

			 and the left edge of the image.

		yoffset: The number of pixels between the top of the screen

			 and the top edge of the image.

What:		/sys/firmware/acpi/interrupts/

Date:		February 2008

Contact:	Len Brown <lenb@kernel.org>

	  load additional kernel modules after boot, this feature may be used

	  to override that restriction).

config ACPI_BGRT

        tristate "Boottime Graphics Resource Table support"

        default n

        help

	  This driver adds support for exposing the ACPI Boottime Graphics

	  Resource Table, which allows the operating system to obtain

	  data from the firmware boot splash. It will appear under

	  /sys/firmware/acpi/bgrt/ .

source "drivers/acpi/apei/Kconfig"

endif	# ACPI

obj-$(CONFIG_ACPI_HED)		+= hed.o

obj-$(CONFIG_ACPI_EC_DEBUGFS)	+= ec_sys.o

obj-$(CONFIG_ACPI_CUSTOM_METHOD)+= custom_method.o

obj-$(CONFIG_ACPI_BGRT)		+= bgrt.o

# processor has its own "processor." module_param namespace

processor-y			:= processor_driver.o processor_throttling.o

/*

 * Copyright 2012 Red Hat, Inc <mjg@redhat.com>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 */

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/init.h>

#include <linux/device.h>

#include <linux/sysfs.h>

#include <acpi/acpi.h>

#include <acpi/acpi_bus.h>

static struct acpi_table_bgrt *bgrt_tab;

static struct kobject *bgrt_kobj;

struct bmp_header {

	u16 id;

	u32 size;

} __attribute ((packed));

static struct bmp_header bmp_header;

static ssize_t show_version(struct device *dev,

			    struct device_attribute *attr, char *buf)

{

	return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab->version);

}

static DEVICE_ATTR(version, S_IRUGO, show_version, NULL);

static ssize_t show_status(struct device *dev,

			   struct device_attribute *attr, char *buf)

{

	return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab->status);

}

static DEVICE_ATTR(status, S_IRUGO, show_status, NULL);

static ssize_t show_type(struct device *dev,

			 struct device_attribute *attr, char *buf)

{

	return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab->image_type);

}

static DEVICE_ATTR(type, S_IRUGO, show_type, NULL);

static ssize_t show_xoffset(struct device *dev,

			    struct device_attribute *attr, char *buf)

{

	return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab->image_offset_x);

}

static DEVICE_ATTR(xoffset, S_IRUGO, show_xoffset, NULL);

static ssize_t show_yoffset(struct device *dev,

			    struct device_attribute *attr, char *buf)

{

	return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab->image_offset_y);

}

static DEVICE_ATTR(yoffset, S_IRUGO, show_yoffset, NULL);

static ssize_t show_image(struct file *file, struct kobject *kobj,

	       struct bin_attribute *attr, char *buf, loff_t off, size_t count)

{

	int size = attr->size;

	void __iomem *image = attr->private;

	if (off >= size) {

		count = 0;

	} else {

		if (off + count > size)

			count = size - off;

		memcpy_fromio(buf, image+off, count);

	}

	return count;

}

static struct bin_attribute image_attr = {

	.attr = {

		.name = "image",

		.mode = S_IRUGO,

	},

	.read = show_image,

};

static struct attribute *bgrt_attributes[] = {

	&dev_attr_version.attr,

	&dev_attr_status.attr,

	&dev_attr_type.attr,

	&dev_attr_xoffset.attr,

	&dev_attr_yoffset.attr,

	NULL,

};

static struct attribute_group bgrt_attribute_group = {

	.attrs = bgrt_attributes,

};

static int __init bgrt_init(void)

{

	acpi_status status;

	int ret;

	void __iomem *bgrt;

	if (acpi_disabled)

		return -ENODEV;

	status = acpi_get_table("BGRT", 0,

				(struct acpi_table_header **)&bgrt_tab);

	if (ACPI_FAILURE(status))

		return -ENODEV;

	sysfs_bin_attr_init(&image_attr);

	bgrt = ioremap(bgrt_tab->image_address, sizeof(struct bmp_header));

	if (!bgrt) {

		ret = -EINVAL;

		goto out_err;

	}

	memcpy_fromio(&bmp_header, bgrt, sizeof(bmp_header));

	image_attr.size = bmp_header.size;

	iounmap(bgrt);

	image_attr.private = ioremap(bgrt_tab->image_address, image_attr.size);

	if (!image_attr.private) {

		ret = -EINVAL;

		goto out_err;

	}

	bgrt_kobj = kobject_create_and_add("bgrt", acpi_kobj);

	if (!bgrt_kobj) {

		ret = -EINVAL;

		goto out_iounmap;

	}

	ret = sysfs_create_group(bgrt_kobj, &bgrt_attribute_group);

	if (ret)

		goto out_kobject;

	ret = sysfs_create_bin_file(bgrt_kobj, &image_attr);

	if (ret)

		goto out_group;

	return 0;

out_group:

	sysfs_remove_group(bgrt_kobj, &bgrt_attribute_group);

out_kobject:

	kobject_put(bgrt_kobj);

out_iounmap:

	iounmap(image_attr.private);

out_err:

	return ret;

}

static void __exit bgrt_exit(void)

{

	iounmap(image_attr.private);

	sysfs_remove_group(bgrt_kobj, &bgrt_attribute_group);

	sysfs_remove_bin_file(bgrt_kobj, &image_attr);

}

module_init(bgrt_init);

module_exit(bgrt_exit);

MODULE_AUTHOR("Matthew Garrett");

MODULE_DESCRIPTION("BGRT boot graphic support");

MODULE_LICENSE("GPL");