Re: [PATCH V2 2/2] ACPI: Add support for exposing BGRT data

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Tue, Jan 31, 2012 at 01:19:20PM -0500, Matthew Garrett wrote:
> ACPI 5.0 adds the BGRT, a table that contains a pointer to the firmware
> boot splash and associated metadata. This simple driver exposes it via
> /sys/firmware/acpi in order to allow bootsplash applications to draw their
> splash around the firmware image and reduce the number of jarring graphical
> transitions during boot.
> 
> Signed-off-by: Matthew Garrett <mjg@redhat.com>
> ---
>  Documentation/ABI/testing/sysfs-firmware-acpi |   20 +++
>  drivers/acpi/Kconfig                          |    9 ++
>  drivers/acpi/Makefile                         |    1 +
>  drivers/acpi/bgrt.c                           |  175 +++++++++++++++++++++++++
>  4 files changed, 205 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/acpi/bgrt.c
> 
> diff --git a/Documentation/ABI/testing/sysfs-firmware-acpi b/Documentation/ABI/testing/sysfs-firmware-acpi
> index 4f9ba3c..dd930c8 100644
> --- a/Documentation/ABI/testing/sysfs-firmware-acpi
> +++ b/Documentation/ABI/testing/sysfs-firmware-acpi
> @@ -1,3 +1,23 @@
> +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>
> diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
> index 7556913..47768ff 100644
> --- a/drivers/acpi/Kconfig
> +++ b/drivers/acpi/Kconfig
> @@ -384,6 +384,15 @@ config ACPI_CUSTOM_METHOD
>  	  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

Should it depend on the SYSFS?

> +        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
> diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
> index 1567028..47199e2 100644
> --- a/drivers/acpi/Makefile
> +++ b/drivers/acpi/Makefile
> @@ -62,6 +62,7 @@ obj-$(CONFIG_ACPI_SBS)		+= sbs.o
>  obj-$(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
> diff --git a/drivers/acpi/bgrt.c b/drivers/acpi/bgrt.c
> new file mode 100644
> index 0000000..8cf6c46
> --- /dev/null
> +++ b/drivers/acpi/bgrt.c
> @@ -0,0 +1,175 @@
> +/*
> + * 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");
> -- 
> 1.7.7.1
> 
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