m68k/PCI: Use pci_enable_resources() in pcibios_enable_device()

m68k has a resource enable (check) loop in its pcibios_enable_device()
which for some reason differs from pci_enable_resources(). This could lead
to inconsistencies in behavior, especially now as pci_enable_resources()
and the bridge window resource flags behavior are going to be altered by
upcoming changes.

The check for !r->start && r->end is already covered by the more generic
checks done in pci_enable_resources().

The entire pcibios_enable_device() suspiciously looks copy-paste from some
other arch as also indicated by the preceding comment. However, it also
enables PCI_COMMAND_IO | PCI_COMMAND_MEMORY always for bridges. It is not
clear why that is being done as the commit e93a6bbeb5a5 ("m68k: common PCI
support definitions and code") introducing this code states "Nothing
specific to any PCI implementation in any m68k class CPU hardware yet".

Replace the resource enable loop with a call to pci_enable_resources() and
adjust the Command Register afterwards as it's unclear if that is necessary
or not so keep it for now.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://patch.msgid.link/20250829131113.36754-2-ilpo.jarvinen@linux.intel.com

1 files changed, 11 insertions, 28 deletions

diff --git a/arch/m68k/kernel/pcibios.c b/arch/m68k/kernel/pcibios.c
index 9504eb19d73a..e6ab3f9ff5d8 100644
--- a/arch/m68k/kernel/pcibios.c
+++ b/arch/m68k/kernel/pcibios.c
@@ -44,41 +44,24 @@ resource_size_t pcibios_align_resource(void *data, const struct resource *res,
  */
 int pcibios_enable_device(struct pci_dev *dev, int mask)
 {
-	struct resource *r;
 	u16 cmd, newcmd;
-	int idx;
+	int ret;
 
-	pci_read_config_word(dev, PCI_COMMAND, &cmd);
-	newcmd = cmd;
-
-	for (idx = 0; idx < 6; idx++) {
-		/* Only set up the requested stuff */
-		if (!(mask & (1 << idx)))
-			continue;
-
-		r = dev->resource + idx;
-		if (!r->start && r->end) {
-			pr_err("PCI: Device %s not available because of resource collisions\n",
-				pci_name(dev));
-			return -EINVAL;
-		}
-		if (r->flags & IORESOURCE_IO)
-			newcmd |= PCI_COMMAND_IO;
-		if (r->flags & IORESOURCE_MEM)
-			newcmd |= PCI_COMMAND_MEMORY;
-	}
+	ret = pci_enable_resources(dev, mask);
+	if (ret < 0)
+		return ret;
 
 	/*
 	 * Bridges (eg, cardbus bridges) need to be fully enabled
 	 */
-	if ((dev->class >> 16) == PCI_BASE_CLASS_BRIDGE)
+	if ((dev->class >> 16) == PCI_BASE_CLASS_BRIDGE) {
+		pci_read_config_word(dev, PCI_COMMAND, &cmd);
 		newcmd |= PCI_COMMAND_IO | PCI_COMMAND_MEMORY;
-
-
-	if (newcmd != cmd) {
-		pr_info("PCI: enabling device %s (0x%04x -> 0x%04x)\n",
-			pci_name(dev), cmd, newcmd);
-		pci_write_config_word(dev, PCI_COMMAND, newcmd);
+		if (newcmd != cmd) {
+			pr_info("PCI: enabling bridge %s (0x%04x -> 0x%04x)\n",
+				pci_name(dev), cmd, newcmd);
+			pci_write_config_word(dev, PCI_COMMAND, newcmd);
+		}
 	}
 	return 0;
 }