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authorJavier Martinez Canillas <javierm@redhat.com>2021-06-25 15:09:46 +0200
committerThomas Zimmermann <tzimmermann@suse.de>2021-07-21 12:04:56 +0200
commitd391c58271072d0b0fad93c82018d495b2633448 (patch)
tree3988519a245873dcc3311434ad89f438a952e26a /drivers/firmware/sysfb_simplefb.c
parentbf44e8cecc03c9c6197c0b65d54703746a62fb35 (diff)
drivers/firmware: move x86 Generic System Framebuffers support
The x86 architecture has generic support to register a system framebuffer platform device. It either registers a "simple-framebuffer" if the config option CONFIG_X86_SYSFB is enabled, or a legacy VGA/VBE/EFI FB device. But the code is generic enough to be reused by other architectures and can be moved out of the arch/x86 directory. This will allow to also support the simple{fb,drm} drivers on non-x86 EFI platforms, such as aarch64 where these drivers are only supported with DT. Signed-off-by: Javier Martinez Canillas <javierm@redhat.com> Acked-by: Borislav Petkov <bp@suse.de> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Link: https://patchwork.freedesktop.org/patch/msgid/20210625130947.1803678-2-javierm@redhat.com
Diffstat (limited to 'drivers/firmware/sysfb_simplefb.c')
-rw-r--r--drivers/firmware/sysfb_simplefb.c111
1 files changed, 111 insertions, 0 deletions
diff --git a/drivers/firmware/sysfb_simplefb.c b/drivers/firmware/sysfb_simplefb.c
new file mode 100644
index 000000000000..df892444ea17
--- /dev/null
+++ b/drivers/firmware/sysfb_simplefb.c
@@ -0,0 +1,111 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Generic System Framebuffers on x86
+ * Copyright (c) 2012-2013 David Herrmann <dh.herrmann@gmail.com>
+ */
+
+/*
+ * simple-framebuffer probing
+ * Try to convert "screen_info" into a "simple-framebuffer" compatible mode.
+ * If the mode is incompatible, we return "false" and let the caller create
+ * legacy nodes instead.
+ */
+
+#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 const char simplefb_resname[] = "BOOTFB";
+static const struct simplefb_format formats[] = SIMPLEFB_FORMATS;
+
+/* try parsing x86 screen_info into a simple-framebuffer mode struct */
+__init bool parse_mode(const struct screen_info *si,
+ struct simplefb_platform_data *mode)
+{
+ const struct simplefb_format *f;
+ __u8 type;
+ unsigned int i;
+
+ type = si->orig_video_isVGA;
+ if (type != VIDEO_TYPE_VLFB && type != VIDEO_TYPE_EFI)
+ return false;
+
+ for (i = 0; i < ARRAY_SIZE(formats); ++i) {
+ f = &formats[i];
+ if (si->lfb_depth == f->bits_per_pixel &&
+ si->red_size == f->red.length &&
+ si->red_pos == f->red.offset &&
+ si->green_size == f->green.length &&
+ si->green_pos == f->green.offset &&
+ si->blue_size == f->blue.length &&
+ si->blue_pos == f->blue.offset &&
+ si->rsvd_size == f->transp.length &&
+ si->rsvd_pos == f->transp.offset) {
+ mode->format = f->name;
+ mode->width = si->lfb_width;
+ mode->height = si->lfb_height;
+ mode->stride = si->lfb_linelength;
+ return true;
+ }
+ }
+
+ return false;
+}
+
+__init int create_simplefb(const struct screen_info *si,
+ const struct simplefb_platform_data *mode)
+{
+ struct platform_device *pd;
+ struct resource res;
+ u64 base, size;
+ u32 length;
+
+ /*
+ * If the 64BIT_BASE capability is set, ext_lfb_base will contain the
+ * upper half of the base address. Assemble the address, then make sure
+ * it is valid and we can actually access it.
+ */
+ base = si->lfb_base;
+ if (si->capabilities & VIDEO_CAPABILITY_64BIT_BASE)
+ base |= (u64)si->ext_lfb_base << 32;
+ if (!base || (u64)(resource_size_t)base != base) {
+ printk(KERN_DEBUG "sysfb: inaccessible VRAM base\n");
+ return -EINVAL;
+ }
+
+ /*
+ * Don't use lfb_size as IORESOURCE size, since it may contain the
+ * entire VMEM, and thus require huge mappings. Use just the part we
+ * need, that is, the part where the framebuffer is located. But verify
+ * that it does not exceed the advertised VMEM.
+ * Note that in case of VBE, the lfb_size is shifted by 16 bits for
+ * historical reasons.
+ */
+ size = si->lfb_size;
+ if (si->orig_video_isVGA == VIDEO_TYPE_VLFB)
+ size <<= 16;
+ length = mode->height * mode->stride;
+ if (length > size) {
+ printk(KERN_WARNING "sysfb: VRAM smaller than advertised\n");
+ return -EINVAL;
+ }
+ length = PAGE_ALIGN(length);
+
+ /* setup IORESOURCE_MEM as framebuffer memory */
+ memset(&res, 0, sizeof(res));
+ res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
+ res.name = simplefb_resname;
+ res.start = base;
+ res.end = res.start + length - 1;
+ if (res.end <= res.start)
+ return -EINVAL;
+
+ pd = platform_device_register_resndata(NULL, "simple-framebuffer", 0,
+ &res, 1, mode, sizeof(*mode));
+ return PTR_ERR_OR_ZERO(pd);
+}