powerpc/eeh: Move EEH initialisation to an arch initcall

The initialisation of EEH mostly happens in a core_initcall_sync initcall,
followed by registering a bus notifier later on in an arch_initcall.
Anything involving initcall dependecies is mostly incomprehensible unless
you've spent a while staring at code so here's the full sequence:

ppc_md.setup_arch       <-- pci_controllers are created here

...time passes...

core_initcall           <-- pci_dns are created from DT nodes
core_initcall_sync      <-- platforms call eeh_init()
postcore_initcall       <-- PCI bus type is registered
postcore_initcall_sync
arch_initcall           <-- EEH pci_bus notifier registered
subsys_initcall         <-- PHBs are scanned here

There's no real requirement to do the EEH setup at the core_initcall_sync
level. It just needs to be done after pci_dn's are created and before we
start scanning PHBs. Simplify the flow a bit by moving the platform EEH
inititalisation to an arch_initcall so we can fold the bus notifier
registration into eeh_init().

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200918093050.37344-5-oohall@gmail.com

arch/powerpc/kernel/eeh.c

@@ -940,41 +940,6 @@ static struct notifier_block eeh_reboot_nb = {
 	.notifier_call = eeh_reboot_notifier,
 };
 
-/**
- * eeh_init - System wide EEH initialization
- *
- * It's the platform's job to call this from an arch_initcall().
- */
-int eeh_init(struct eeh_ops *ops)
-{
-	struct pci_controller *hose, *tmp;
-	int ret = 0;
-
-	/* the platform should only initialise EEH once */
-	if (WARN_ON(eeh_ops))
-		return -EEXIST;
-	if (WARN_ON(!ops))
-		return -ENOENT;
-	eeh_ops = ops;
-
-	/* Register reboot notifier */
-	ret = register_reboot_notifier(&eeh_reboot_nb);
-	if (ret) {
-		pr_warn("%s: Failed to register notifier (%d)\n",
-			__func__, ret);
-		return ret;
-	}
-
-	/* Initialize PHB PEs */
-	list_for_each_entry_safe(hose, tmp, &hose_list, list_node)
-		eeh_phb_pe_create(hose);
-
-	eeh_addr_cache_init();
-
-	/* Initialize EEH event */
-	return eeh_event_init();
-}
-
 static int eeh_device_notifier(struct notifier_block *nb,
 			       unsigned long action, void *data)
 {
@@ -999,12 +964,47 @@ static struct notifier_block eeh_device_nb = {
 	.notifier_call = eeh_device_notifier,
 };
 
-static __init int eeh_set_bus_notifier(void)
+/**
+ * eeh_init - System wide EEH initialization
+ *
+ * It's the platform's job to call this from an arch_initcall().
+ */
+int eeh_init(struct eeh_ops *ops)
 {
-	bus_register_notifier(&pci_bus_type, &eeh_device_nb);
+	struct pci_controller *hose, *tmp;
-	return 0;
+	int ret = 0;
+
+	/* the platform should only initialise EEH once */
+	if (WARN_ON(eeh_ops))
+		return -EEXIST;
+	if (WARN_ON(!ops))
+		return -ENOENT;
+	eeh_ops = ops;
+
+	/* Register reboot notifier */
+	ret = register_reboot_notifier(&eeh_reboot_nb);
+	if (ret) {
+		pr_warn("%s: Failed to register reboot notifier (%d)\n",
+			__func__, ret);
+		return ret;
+	}
+
+	ret = bus_register_notifier(&pci_bus_type, &eeh_device_nb);
+	if (ret) {
+		pr_warn("%s: Failed to register bus notifier (%d)\n",
+			__func__, ret);
+		return ret;
+	}
+
+	/* Initialize PHB PEs */
+	list_for_each_entry_safe(hose, tmp, &hose_list, list_node)
+		eeh_phb_pe_create(hose);
+
+	eeh_addr_cache_init();
+
+	/* Initialize EEH event */
+	return eeh_event_init();
 }
-arch_initcall(eeh_set_bus_notifier);
 
 /**
  * eeh_probe_device() - Perform EEH initialization for the indicated pci device

arch/powerpc/platforms/powernv/eeh-powernv.c

@@ -1721,4 +1721,4 @@ static int __init eeh_powernv_init(void)
 
 	return ret;
 }
-machine_core_initcall_sync(powernv, eeh_powernv_init);
+machine_arch_initcall(powernv, eeh_powernv_init);

arch/powerpc/platforms/pseries/eeh_pseries.c

@@ -985,4 +985,4 @@ static int __init eeh_pseries_init(void)
 			ret);
 	return ret;
 }
-machine_core_initcall_sync(pseries, eeh_pseries_init);
+machine_arch_initcall(pseries, eeh_pseries_init);