ARM: remove support for NOMMU ARMv4/v5

It is possible to build MMU-less kernels for Cortex-M base
microcrontrollers as well as a couple of older platforms that
have not been converted to CONFIG_ARCH_MULTIPLATFORM,
specifically ep93xx, footbridge, dove, sa1100 and s3c24xx.

It seems unlikely that anybody has tested those configurations
in recent years, as even building them is frequently broken.
A patch I submitted caused another build time regression
in this configuration. I sent a patch for that, but it seems
better to also remove the option entirely, leaving ARMv7-M
as the only supported Arm NOMMU target for simplicity.

A couple of platforms have dependencies on CONFIG_MMU, those
can all be removed now. Notably, mach-integrator tries to
support MMU-less CPU cores, but those have not actually been
selectable for a long time.

This addresses several build failures in randconfig builds that
have accumulated over the years.

Cc: Vladimir Murzin <vladimir.murzin@arm.com>
Cc: Russell King <linux@armlinux.org.uk>
Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 13 insertions, 21 deletions

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index d9142ad18c52..8d6ed7331e50 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -292,6 +292,17 @@ config MMU
 	  Select if you want MMU-based virtualised addressing space
 	  support by paged memory management. If unsure, say 'Y'.
 
+config ARM_SINGLE_ARMV7M
+	def_bool !MMU
+	select ARM_NVIC
+	select AUTO_ZRELADDR
+	select TIMER_OF
+	select COMMON_CLK
+	select CPU_V7M
+	select NO_IOPORT_MAP
+	select SPARSE_IRQ
+	select USE_OF
+
 config ARCH_MMAP_RND_BITS_MIN
 	default 8
 
@@ -306,12 +317,11 @@ config ARCH_MMAP_RND_BITS_MAX
 #
 choice
 	prompt "ARM system type"
-	default ARM_SINGLE_ARMV7M if !MMU
-	default ARCH_MULTIPLATFORM if MMU
+	depends on MMU
+	default ARCH_MULTIPLATFORM
 
 config ARCH_MULTIPLATFORM
 	bool "Allow multiple platforms to be selected"
-	depends on MMU
 	select ARCH_FLATMEM_ENABLE
 	select ARCH_SPARSEMEM_ENABLE
 	select ARCH_SELECT_MEMORY_MODEL
@@ -326,18 +336,6 @@ config ARCH_MULTIPLATFORM
 	select SPARSE_IRQ
 	select USE_OF
 
-config ARM_SINGLE_ARMV7M
-	bool "ARMv7-M based platforms (Cortex-M0/M3/M4)"
-	depends on !MMU
-	select ARM_NVIC
-	select AUTO_ZRELADDR
-	select TIMER_OF
-	select COMMON_CLK
-	select CPU_V7M
-	select NO_IOPORT_MAP
-	select SPARSE_IRQ
-	select USE_OF
-
 config ARCH_EP93XX
 	bool "EP93xx-based"
 	select ARCH_SPARSEMEM_ENABLE
@@ -357,7 +355,6 @@ config ARCH_FOOTBRIDGE
 	bool "FootBridge"
 	select CPU_SA110
 	select FOOTBRIDGE
-	select NEED_MACH_IO_H if !MMU
 	select NEED_MACH_MEMORY_H
 	help
 	  Support for systems based on the DC21285 companion chip
@@ -365,7 +362,6 @@ config ARCH_FOOTBRIDGE
 
 config ARCH_IOP32X
 	bool "IOP32x-based"
-	depends on MMU
 	select CPU_XSCALE
 	select GPIO_IOP
 	select GPIOLIB
@@ -378,7 +374,6 @@ config ARCH_IOP32X
 
 config ARCH_IXP4XX
 	bool "IXP4xx-based"
-	depends on MMU
 	select ARCH_SUPPORTS_BIG_ENDIAN
 	select ARM_PATCH_PHYS_VIRT
 	select CPU_XSCALE
@@ -411,7 +406,6 @@ config ARCH_DOVE
 
 config ARCH_PXA
 	bool "PXA2xx/PXA3xx-based"
-	depends on MMU
 	select ARCH_MTD_XIP
 	select ARM_CPU_SUSPEND if PM
 	select AUTO_ZRELADDR
@@ -431,7 +425,6 @@ config ARCH_PXA
 
 config ARCH_RPC
 	bool "RiscPC"
-	depends on MMU
 	depends on !CC_IS_CLANG && GCC_VERSION < 90100 && GCC_VERSION >= 60000
 	select ARCH_ACORN
 	select ARCH_MAY_HAVE_PC_FDC
@@ -488,7 +481,6 @@ config ARCH_S3C24XX
 
 config ARCH_OMAP1
 	bool "TI OMAP1"
-	depends on MMU
 	select ARCH_OMAP
 	select CLKSRC_MMIO
 	select GENERIC_IRQ_CHIP