From bc824922b264aff40eba8c160972ee07a95e7dd4 Mon Sep 17 00:00:00 2001 From: Javier Martinez Canillas Date: Tue, 7 Jun 2022 20:23:35 +0200 Subject: [PATCH] firmware: sysfb: Add sysfb_disable() helper function This can be used by subsystems to unregister a platform device registered by sysfb and also to disable future platform device registration in sysfb. Suggested-by: Daniel Vetter Signed-off-by: Javier Martinez Canillas Reviewed-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20220607182338.344270-3-javierm@redhat.com --- .../driver-api/firmware/other_interfaces.rst | 6 +++ drivers/firmware/sysfb.c | 54 ++++++++++++++++--- include/linux/sysfb.h | 12 +++++ 3 files changed, 66 insertions(+), 6 deletions(-) diff --git a/Documentation/driver-api/firmware/other_interfaces.rst b/Documentation/driver-api/firmware/other_interfaces.rst index b81794e0cfbb..06ac89adaafb 100644 --- a/Documentation/driver-api/firmware/other_interfaces.rst +++ b/Documentation/driver-api/firmware/other_interfaces.rst @@ -13,6 +13,12 @@ EDD Interfaces .. kernel-doc:: drivers/firmware/edd.c :internal: +Generic System Framebuffers Interface +------------------------------------- + +.. kernel-doc:: drivers/firmware/sysfb.c + :export: + Intel Stratix10 SoC Service Layer --------------------------------- Some features of the Intel Stratix10 SoC require a level of privilege diff --git a/drivers/firmware/sysfb.c b/drivers/firmware/sysfb.c index b032f40a92de..1f276f108cc9 100644 --- a/drivers/firmware/sysfb.c +++ b/drivers/firmware/sysfb.c @@ -34,21 +34,59 @@ #include #include +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; - struct platform_device *pd; const char *name; bool compatible; - int ret; + int ret = 0; + + mutex_lock(&disable_lock); + if (disabled) + goto unlock_mutex; /* 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)) - return 0; + goto unlock_mutex; } /* if the FB is incompatible, create a legacy framebuffer device */ @@ -60,8 +98,10 @@ static __init int sysfb_init(void) name = "platform-framebuffer"; pd = platform_device_alloc(name, 0); - if (!pd) - return -ENOMEM; + if (!pd) { + ret = -ENOMEM; + goto unlock_mutex; + } sysfb_apply_efi_quirks(pd); @@ -73,9 +113,11 @@ static __init int sysfb_init(void) if (ret) goto err; - return 0; + goto unlock_mutex; err: platform_device_put(pd); +unlock_mutex: + mutex_unlock(&disable_lock); return ret; } diff --git a/include/linux/sysfb.h b/include/linux/sysfb.h index 708152e9037b..8ba8b5be5567 100644 --- a/include/linux/sysfb.h +++ b/include/linux/sysfb.h @@ -55,6 +55,18 @@ struct efifb_dmi_info { int flags; }; +#ifdef CONFIG_SYSFB + +void sysfb_disable(void); + +#else /* CONFIG_SYSFB */ + +static inline void sysfb_disable(void) +{ +} + +#endif /* CONFIG_SYSFB */ + #ifdef CONFIG_EFI extern struct efifb_dmi_info efifb_dmi_list[]; -- 2.34.1