ACPI: Add support for exposing BGRT data

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>
Signed-off-by: Len Brown <len.brown@intel.com>

3 files changed, 185 insertions, 0 deletions

diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index 7556913aba45..47768ff87343 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
+        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 1567028d2038..47199e2a9130 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 000000000000..8cf6c46e99fb
--- /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");