m68k/mm: make node data and node setup depend on CONFIG_DISCONTIGMEM

The pg_data_t node structures and their initialization currently depends on
!CONFIG_SINGLE_MEMORY_CHUNK. Since they are required only for DISCONTIGMEM
make this dependency explicit and replace usage of
CONFIG_SINGLE_MEMORY_CHUNK with CONFIG_DISCONTIGMEM where appropriate.

The CONFIG_SINGLE_MEMORY_CHUNK was implicitly disabled on the ColdFire MMU
variant, although it always presumed a single memory bank. As there is no
actual need for DISCONTIGMEM in this case, make sure that ColdFire MMU
systems set CONFIG_SINGLE_MEMORY_CHUNK to 'y'.

Link: https://lkml.kernel.org/r/20201101170454.9567-12-rppt@kernel.org
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Meelis Roos <mroos@linux.ee>
Cc: Michael Schmitz <schmitzmic@gmail.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/m68k/Kconfig.cpu

@@ -373,7 +373,7 @@ config RMW_INSNS
 config SINGLE_MEMORY_CHUNK
 	bool "Use one physical chunk of memory only" if ADVANCED && !SUN3
 	depends on MMU
-	default y if SUN3
+	default y if SUN3 || MMU_COLDFIRE
 	select NEED_MULTIPLE_NODES
 	help
 	  Ignore all but the first contiguous chunk of physical memory for VM
@@ -406,7 +406,7 @@ config M68K_L2_CACHE
 config NODES_SHIFT
 	int
 	default "3"
-	depends on !SINGLE_MEMORY_CHUNK
+	depends on DISCONTIGMEM
 
 config CPU_HAS_NO_BITFIELDS
 	bool

arch/m68k/include/asm/page_mm.h

@@ -126,7 +126,7 @@ static inline void *__va(unsigned long x)
 
 extern int m68k_virt_to_node_shift;
 
-#ifdef CONFIG_SINGLE_MEMORY_CHUNK
+#ifndef CONFIG_DISCONTIGMEM
 #define __virt_to_node(addr)	(&pg_data_map[0])
 #else
 extern struct pglist_data *pg_data_table[];

arch/m68k/include/asm/virtconvert.h

@@ -29,7 +29,7 @@ static inline void *phys_to_virt(unsigned long address)
 }
 
 /* Permanent address of a page. */
-#if defined(CONFIG_MMU) && defined(CONFIG_SINGLE_MEMORY_CHUNK)
+#if defined(CONFIG_MMU) && !defined(CONFIG_DISCONTIGMEM)
 #define page_to_phys(page) \
 	__pa(PAGE_OFFSET + (((page) - pg_data_map[0].node_mem_map) << PAGE_SHIFT))
 #else

arch/m68k/mm/init.c

@@ -47,14 +47,14 @@ EXPORT_SYMBOL(pg_data_map);
 
 int m68k_virt_to_node_shift;
 
-#ifndef CONFIG_SINGLE_MEMORY_CHUNK
+#ifdef CONFIG_DISCONTIGMEM
 pg_data_t *pg_data_table[65];
 EXPORT_SYMBOL(pg_data_table);
 #endif
 
 void __init m68k_setup_node(int node)
 {
-#ifndef CONFIG_SINGLE_MEMORY_CHUNK
+#ifdef CONFIG_DISCONTIGMEM
 	struct m68k_mem_info *info = m68k_memory + node;
 	int i, end;