[RFC PATCH v2 11/13] bootsplash: sysfs entries to load and unload files

Max Staudt
2017-12-13T19:49:54Z

Users can use this to replace their splash screen at runtime by writing
a path and filename to /sys/devices/platform/bootsplash.0/load_file and
making sure the splash is enabled.

Notes:
- The path has to be a path in /lib/firmware since request_firmware()
is used to fetch the data.
- When setting the splash from the shell, echo -n has to be used as
any trailing '\n' newline will be interpreted as part of the path.

Writes to /sys/devices/platform/bootsplash.0/drop_splash will cause the
current splash theme to be freed and the console to switch to text mode,

Signed-off-by: Max Staudt <mstaudt@suse.de>
---
.../ABI/testing/sysfs-platform-bootsplash | 32 +++++++++++++
Documentation/bootsplash.rst | 8 ++++
drivers/video/fbdev/core/bootsplash.c | 54 ++++++++++++++++++++++
3 files changed, 94 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-platform-bootsplash b/Documentation/ABI/testing/sysfs-platform-bootsplash
index 742c7b035ded..f8f4b259220e 100644
--- a/Documentation/ABI/testing/sysfs-platform-bootsplash
+++ b/Documentation/ABI/testing/sysfs-platform-bootsplash
@@ -9,3 +9,35 @@ Description:
1: Splash is shown whenever fbcon would show a text console
(i.e. no graphical application is running), and a splash
file is loaded.
+
+What: /sys/devices/platform/bootsplash.0/drop_splash
+Date: Oct 2017
+KernelVersion: 4.14
+Contact: Max Staudt <mstaudt@suse.de>
+Description:
+ Can only be set.
+
+ Any value written will cause the current splash theme file
+ to be unloaded and the text console to be redrawn.
+
+What: /sys/devices/platform/bootsplash.0/load_file
+Date: Oct 2017
+KernelVersion: 4.14
+Contact: Max Staudt <mstaudt@suse.de>
+Description:
+ Can only be set.
+
+ Any value written will cause the splash to be disabled and
+ internal memory structures to be freed.
+
+ A firmware path written will cause a new theme file to be
+ loaded and the current bootsplash to be replaced.
+ The current enabled/disabled status is not touched.
+ If the splash is already active, it will be redrawn.
+
+ The path has to be a path in /lib/firmware since
+ request_firmware() is used to fetch the data.
+
+ When setting the splash from the shell, echo -n has to be
+ used as any trailing '\n' newline will be interpreted as
+ part of the path.
diff --git a/Documentation/bootsplash.rst b/Documentation/bootsplash.rst
index 8bd6805af6bf..d793612ebf2e 100644
--- a/Documentation/bootsplash.rst
+++ b/Documentation/bootsplash.rst
@@ -58,6 +58,14 @@ sysfs run-time configuration
a splash theme file is also loaded.

+``/sys/devices/platform/bootsplash.0/drop_splash``
+ Unload splash data and free memory.
+
+``/sys/devices/platform/bootsplash.0/load_file``
+ Load a splash file from ``/lib/firmware/``.
+ Note that trailing newlines will be interpreted as part of the file name.
+
+

Kconfig
=======
diff --git a/drivers/video/fbdev/core/bootsplash.c b/drivers/video/fbdev/core/bootsplash.c
index 13fcaabbc2ca..16cb0493629d 100644
--- a/drivers/video/fbdev/core/bootsplash.c
+++ b/drivers/video/fbdev/core/bootsplash.c
@@ -251,11 +251,65 @@ static ssize_t splash_store_enabled(struct device *device,
return count;
}

+static ssize_t splash_store_drop_splash(struct device *device,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct splash_file_priv *fp;
+
+ if (!buf || !count || !splash_state.file)
+ return count;
+
+ mutex_lock(&splash_state.data_lock);
+ fp = splash_state.file;
+ splash_state.file = NULL;
+ mutex_unlock(&splash_state.data_lock);
+
+ /* Redraw the text console */
+ schedule_work(&splash_state.work_redraw_vc);
+
+ bootsplash_free_file(fp);
+
+ return count;
+}
+
+static ssize_t splash_store_load_file(struct device *device,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct splash_file_priv *fp, *fp_old;
+
+ if (!count)
+ return 0;
+
+ fp = bootsplash_load_firmware(&splash_state.splash_device->dev,
+ buf);
+
+ if (!fp)
+ return -ENXIO;
+
+ mutex_lock(&splash_state.data_lock);
+ fp_old = splash_state.file;
+ splash_state.splash_fb = NULL;
+ splash_state.file = fp;
+ mutex_unlock(&splash_state.data_lock);
+
+ /* Update the splash or text console */
+ schedule_work(&splash_state.work_redraw_vc);
+
+ bootsplash_free_file(fp_old);
+ return count;
+}
+
static DEVICE_ATTR(enabled, 0644, splash_show_enabled, splash_store_enabled);
+static DEVICE_ATTR(drop_splash, 0200, NULL, splash_store_drop_splash);
+static DEVICE_ATTR(load_file, 0200, NULL, splash_store_load_file);

static struct attribute *splash_dev_attrs[] = {
&dev_attr_enabled.attr,
+ &dev_attr_drop_splash.attr,
+ &dev_attr_load_file.attr,
NULL
};

--
2.12.3