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-rw-r--r--drivers/firmware/sysfb.c131
1 files changed, 131 insertions, 0 deletions
diff --git a/drivers/firmware/sysfb.c b/drivers/firmware/sysfb.c
new file mode 100644
index 0000000000..3c197db42c
--- /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);