drivers/firmware: consolidate EFI framebuffer setup for all arches

The register_gop_device() function registers an "efi-framebuffer" platform
device to match against the efifb driver, to have an early framebuffer for
EFI platforms.

But there is already support to do exactly the same by the Generic System
Framebuffers (sysfb) driver. This used to be only for X86 but it has been
moved to drivers/firmware and could be reused by other architectures.

Also, besides supporting registering an "efi-framebuffer", this driver can
register a "simple-framebuffer" allowing to use the siple{fb,drm} drivers
on non-X86 EFI platforms. For example, on aarch64 these drivers can only
be used with DT and doesn't have code to register a "simple-frambuffer"
platform device when booting with EFI.

For these reasons, let's remove the register_gop_device() duplicated code
and instead move the platform specific logic that's there to sysfb driver.

Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Acked-by: Borislav Petkov <bp@suse.de>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20210625131359.1804394-1-javierm@redhat.com

1 files changed, 74 insertions, 2 deletions

diff --git a/drivers/firmware/efi/sysfb_efi.c b/drivers/firmware/efi/sysfb_efi.c
index 9f035b15501c..f51865e1b876 100644
--- a/drivers/firmware/efi/sysfb_efi.c
+++ b/drivers/firmware/efi/sysfb_efi.c
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
- * Generic System Framebuffers on x86
+ * Generic System Framebuffers
  * Copyright (c) 2012-2013 David Herrmann <dh.herrmann@gmail.com>
  *
  * EFI Quirks Copyright (c) 2006 Edgar Hucek <gimli@dark-green.com>
@@ -19,7 +19,9 @@
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/mm.h>
+#include <linux/of_address.h>
 #include <linux/pci.h>
+#include <linux/platform_device.h>
 #include <linux/screen_info.h>
 #include <linux/sysfb.h>
 #include <video/vga.h>
@@ -267,7 +269,72 @@ static const struct dmi_system_id efifb_dmi_swap_width_height[] __initconst = {
 	{},
 };
 
-__init void sysfb_apply_efi_quirks(void)
+static bool efifb_overlaps_pci_range(const struct of_pci_range *range)
+{
+	u64 fb_base = screen_info.lfb_base;
+
+	if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE)
+		fb_base |= (u64)(unsigned long)screen_info.ext_lfb_base << 32;
+
+	return fb_base >= range->cpu_addr &&
+	       fb_base < (range->cpu_addr + range->size);
+}
+
+static struct device_node *find_pci_overlap_node(void)
+{
+	struct device_node *np;
+
+	for_each_node_by_type(np, "pci") {
+		struct of_pci_range_parser parser;
+		struct of_pci_range range;
+		int err;
+
+		err = of_pci_range_parser_init(&parser, np);
+		if (err) {
+			pr_warn("of_pci_range_parser_init() failed: %d\n", err);
+			continue;
+		}
+
+		for_each_of_pci_range(&parser, &range)
+			if (efifb_overlaps_pci_range(&range))
+				return np;
+	}
+	return NULL;
+}
+
+/*
+ * If the efifb framebuffer is backed by a PCI graphics controller, we have
+ * to ensure that this relation is expressed using a device link when
+ * running in DT mode, or the probe order may be reversed, resulting in a
+ * resource reservation conflict on the memory window that the efifb
+ * framebuffer steals from the PCIe host bridge.
+ */
+static int efifb_add_links(struct fwnode_handle *fwnode)
+{
+	struct device_node *sup_np;
+
+	sup_np = find_pci_overlap_node();
+
+	/*
+	 * If there's no PCI graphics controller backing the efifb, we are
+	 * done here.
+	 */
+	if (!sup_np)
+		return 0;
+
+	fwnode_link_add(fwnode, of_fwnode_handle(sup_np));
+	of_node_put(sup_np);
+
+	return 0;
+}
+
+static const struct fwnode_operations efifb_fwnode_ops = {
+	.add_links = efifb_add_links,
+};
+
+static struct fwnode_handle efifb_fwnode;
+
+__init void sysfb_apply_efi_quirks(struct platform_device *pd)
 {
 	if (screen_info.orig_video_isVGA != VIDEO_TYPE_EFI ||
 	    !(screen_info.capabilities & VIDEO_CAPABILITY_SKIP_QUIRKS))
@@ -281,4 +348,9 @@ __init void sysfb_apply_efi_quirks(void)
 		screen_info.lfb_height = temp;
 		screen_info.lfb_linelength = 4 * screen_info.lfb_width;
 	}
+
+	if (screen_info.orig_video_isVGA == VIDEO_TYPE_EFI && IS_ENABLED(CONFIG_PCI)) {
+		fwnode_init(&efifb_fwnode, &efifb_fwnode_ops);
+		pd->dev.fwnode = &efifb_fwnode;
+	}
 }