powerpc/machdep: Define 'compatible' property in ppc_md and use it

Most probe functions do nothing else than checking whether
the machine is compatible to a given string.

Define that string in ppc_md structure and check it directly from
probe_machine() instead of using ppc_md.probe() for that.

Keep checking in ppc_md.probe() only for more complex probing.

Signed-off-by: Christophe Leroy <[e-mail]>
Signed-off-by: Michael Ellerman <[e-mail]>
Link: https://msgid.link/6cb9865d[e-mail]

arch/powerpc/include/asm/machdep.h

···
 
 struct machdep_calls {
 	const char	*name;
+	const char	*compatible;
 #ifdef CONFIG_PPC64
 #ifdef CONFIG_PM
 	void		(*iommu_restore)(void);

arch/powerpc/kernel/setup-common.c

···
 	for (machine_id = &__machine_desc_start;
 	     machine_id < &__machine_desc_end;
 	     machine_id++) {
-		DBG("  %s ...", machine_id->name);
+		DBG("  %s ...\n", machine_id->name);
+		if (machine_id->compatible && !of_machine_is_compatible(machine_id->compatible))
+			continue;
 		memcpy(&ppc_md, machine_id, sizeof(struct machdep_calls));
-		if (ppc_md.probe()) {
-			DBG(" match !\n");
-			break;
-		}
-		DBG("\n");
+		if (ppc_md.probe && !ppc_md.probe())
+			continue;
+		DBG("   %s match !\n", machine_id->name);
+		break;
 	}
 	/* What can we do if we didn't find ? */
 	if (machine_id >= &__machine_desc_end) {