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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /drivers/firmware/sysfb.c | |
parent | Initial commit. (diff) | |
download | linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip |
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/firmware/sysfb.c')
-rw-r--r-- | drivers/firmware/sysfb.c | 131 |
1 files changed, 131 insertions, 0 deletions
diff --git a/drivers/firmware/sysfb.c b/drivers/firmware/sysfb.c new file mode 100644 index 000000000..3c197db42 --- /dev/null +++ b/drivers/firmware/sysfb.c @@ -0,0 +1,131 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Generic System Framebuffers + * Copyright (c) 2012-2013 David Herrmann <dh.herrmann@gmail.com> + */ + +/* + * Simple-Framebuffer support + * Create a platform-device for any available boot framebuffer. The + * simple-framebuffer platform device is already available on DT systems, so + * this module parses the global "screen_info" object and creates a suitable + * platform device compatible with the "simple-framebuffer" DT object. If + * the framebuffer is incompatible, we instead create a legacy + * "vesa-framebuffer", "efi-framebuffer" or "platform-framebuffer" device and + * pass the screen_info as platform_data. This allows legacy drivers + * to pick these devices up without messing with simple-framebuffer drivers. + * The global "screen_info" is still valid at all times. + * + * If CONFIG_SYSFB_SIMPLEFB is not selected, never register "simple-framebuffer" + * platform devices, but only use legacy framebuffer devices for + * backwards compatibility. + * + * TODO: We set the dev_id field of all platform-devices to 0. This allows + * other OF/DT parsers to create such devices, too. However, they must + * start at offset 1 for this to work. + */ + +#include <linux/err.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/mm.h> +#include <linux/platform_data/simplefb.h> +#include <linux/platform_device.h> +#include <linux/screen_info.h> +#include <linux/sysfb.h> + +static struct platform_device *pd; +static DEFINE_MUTEX(disable_lock); +static bool disabled; + +static bool sysfb_unregister(void) +{ + if (IS_ERR_OR_NULL(pd)) + return false; + + platform_device_unregister(pd); + pd = NULL; + + return true; +} + +/** + * sysfb_disable() - disable the Generic System Framebuffers support + * + * This disables the registration of system framebuffer devices that match the + * generic drivers that make use of the system framebuffer set up by firmware. + * + * It also unregisters a device if this was already registered by sysfb_init(). + * + * Context: The function can sleep. A @disable_lock mutex is acquired to serialize + * against sysfb_init(), that registers a system framebuffer device. + */ +void sysfb_disable(void) +{ + mutex_lock(&disable_lock); + sysfb_unregister(); + disabled = true; + mutex_unlock(&disable_lock); +} +EXPORT_SYMBOL_GPL(sysfb_disable); + +static __init int sysfb_init(void) +{ + struct screen_info *si = &screen_info; + struct simplefb_platform_data mode; + const char *name; + bool compatible; + int ret = 0; + + mutex_lock(&disable_lock); + if (disabled) + goto unlock_mutex; + + sysfb_apply_efi_quirks(); + + /* try to create a simple-framebuffer device */ + compatible = sysfb_parse_mode(si, &mode); + if (compatible) { + pd = sysfb_create_simplefb(si, &mode); + if (!IS_ERR(pd)) + goto unlock_mutex; + } + + /* if the FB is incompatible, create a legacy framebuffer device */ + if (si->orig_video_isVGA == VIDEO_TYPE_EFI) + name = "efi-framebuffer"; + else if (si->orig_video_isVGA == VIDEO_TYPE_VLFB) + name = "vesa-framebuffer"; + else if (si->orig_video_isVGA == VIDEO_TYPE_VGAC) + name = "vga-framebuffer"; + else if (si->orig_video_isVGA == VIDEO_TYPE_EGAC) + name = "ega-framebuffer"; + else + name = "platform-framebuffer"; + + pd = platform_device_alloc(name, 0); + if (!pd) { + ret = -ENOMEM; + goto unlock_mutex; + } + + sysfb_set_efifb_fwnode(pd); + + ret = platform_device_add_data(pd, si, sizeof(*si)); + if (ret) + goto err; + + ret = platform_device_add(pd); + if (ret) + goto err; + + goto unlock_mutex; +err: + platform_device_put(pd); +unlock_mutex: + mutex_unlock(&disable_lock); + return ret; +} + +/* must execute after PCI subsystem for EFI quirks */ +device_initcall(sysfb_init); |