@@ -10,10 +10,12 @@
#define pr_fmt(fmt) "efi: " fmt
#include <linux/efi.h>
+#include <linux/fwnode.h>
#include <linux/init.h>
#include <linux/memblock.h>
#include <linux/mm_types.h>
#include <linux/of.h>
+#include <linux/of_address.h>
#include <linux/of_fdt.h>
#include <linux/platform_device.h>
#include <linux/screen_info.h>
@@ -276,15 +278,112 @@ void __init efi_init(void)
efi_memmap_unmap();
}
+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(const struct fwnode_handle *fwnode,
+ struct device *dev)
+{
+ struct device_node *sup_np;
+ struct device *sup_dev;
+
+ 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;
+
+ sup_dev = get_dev_from_fwnode(&sup_np->fwnode);
+ of_node_put(sup_np);
+
+ /*
+ * Return -ENODEV if the PCI graphics controller device hasn't been
+ * registered yet. This ensures that efifb isn't allowed to probe
+ * and this function is retried again when new devices are
+ * registered.
+ */
+ if (!sup_dev)
+ return -ENODEV;
+
+ /*
+ * If this fails, retrying this function at a later point won't
+ * change anything. So, don't return an error after this.
+ */
+ if (!device_link_add(dev, sup_dev, 0))
+ dev_warn(dev, "device_link_add() failed\n");
+
+ put_device(sup_dev);
+
+ return 0;
+}
+
+static const struct fwnode_operations efifb_fwnode_ops = {
+ .add_links = efifb_add_links,
+};
+
+static struct fwnode_handle efifb_fwnode = {
+ .ops = &efifb_fwnode_ops,
+};
+
static int __init register_gop_device(void)
{
- void *pd;
+ struct platform_device *pd;
+ int err;
if (screen_info.orig_video_isVGA != VIDEO_TYPE_EFI)
return 0;
- pd = platform_device_register_data(NULL, "efi-framebuffer", 0,
- &screen_info, sizeof(screen_info));
- return PTR_ERR_OR_ZERO(pd);
+ pd = platform_device_alloc("efi-framebuffer", 0);
+ if (!pd)
+ return -ENOMEM;
+
+ if (IS_ENABLED(CONFIG_PCI))
+ pd->dev.fwnode = &efifb_fwnode;
+
+ err = platform_device_add_data(pd, &screen_info, sizeof(screen_info));
+ if (err)
+ return err;
+
+ return platform_device_add(pd);
}
subsys_initcall(register_gop_device);