xtensa: rework {CONFIG,PLATFORM}_DEFAULT_MEM_START

Drop PLATFORM_DEFAULT_MEM_START from the platform/hardware.h headers.
Provide definition of CONFIG_DEFAULT_MEM_START always, allow changing it
only in noMMU configurations when PLATFORM_WANT_DEFAULT_MEM is selected.
Change prompt and description so that it's clear that it controls
PAGE_OFFSET and PHYS_OFFSET.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

arch/xtensa/Kconfig

@@ -530,14 +530,13 @@ config PLATFORM_WANT_DEFAULT_MEM
 	def_bool n
 
 config DEFAULT_MEM_START
-	hex "Physical address of the default memory area start"
-	depends on PLATFORM_WANT_DEFAULT_MEM
-	default 0x00000000 if MMU
-	default 0x60000000 if !MMU
-	help
-	  This is the base address of the default memory area.
-	  Default memory area has platform-specific meaning, it may be used
-	  for e.g. early cache initialization.
+	hex
+	prompt "PAGE_OFFSET/PHYS_OFFSET" if !MMU && PLATFORM_WANT_DEFAULT_MEM
+	default 0x60000000 if PLATFORM_WANT_DEFAULT_MEM
+	default 0x00000000
+	help
+	  This is the base address used for both PAGE_OFFSET and PHYS_OFFSET
+	  in noMMU configurations.
 
 	  If unsure, leave the default value here.
 

arch/xtensa/include/asm/page.h

@@ -14,7 +14,6 @@
 #include <asm/processor.h>
 #include <asm/types.h>
 #include <asm/cache.h>
-#include <platform/hardware.h>
 #include <asm/kmem_layout.h>
 
 /*
@@ -31,8 +30,8 @@
 #define MAX_LOW_PFN	(PHYS_PFN(XCHAL_KSEG_PADDR) + \
 			 PHYS_PFN(XCHAL_KSEG_SIZE))
 #else
-#define PAGE_OFFSET	PLATFORM_DEFAULT_MEM_START
-#define PHYS_OFFSET	PLATFORM_DEFAULT_MEM_START
+#define PAGE_OFFSET	_AC(CONFIG_DEFAULT_MEM_START, UL)
+#define PHYS_OFFSET	_AC(CONFIG_DEFAULT_MEM_START, UL)
 #define MAX_LOW_PFN	PHYS_PFN(0xfffffffful)
 #endif
 

arch/xtensa/platforms/iss/include/platform/hardware.h

@@ -15,14 +15,4 @@
 #ifndef _XTENSA_PLATFORM_ISS_HARDWARE_H
 #define _XTENSA_PLATFORM_ISS_HARDWARE_H
 
-/*
- * Memory configuration.
- */
-
-#define PLATFORM_DEFAULT_MEM_START	0x00000000
-
-/*
- * Interrupt configuration.
- */
-
 #endif /* _XTENSA_PLATFORM_ISS_HARDWARE_H */

arch/xtensa/platforms/xt2000/include/platform/hardware.h

@@ -17,12 +17,6 @@
 
 #include <variant/core.h>
 
-/* 
- * Memory configuration.
- */
-
-#define PLATFORM_DEFAULT_MEM_START 0x00000000
-
 /*
  * Number of platform IRQs
  */

arch/xtensa/platforms/xtfpga/include/platform/hardware.h

@@ -17,10 +17,6 @@
 #ifndef __XTENSA_XTAVNET_HARDWARE_H
 #define __XTENSA_XTAVNET_HARDWARE_H
 
-/* Memory configuration. */
-
-#define PLATFORM_DEFAULT_MEM_START __XTENSA_UL(CONFIG_DEFAULT_MEM_START)
-
 /* Interrupt configuration. */
 
 #define PLATFORM_NR_IRQS	0