xtensa: add support for the Xtensa architecture

The Xtensa architecture had been removed because it required special
handling and depended on additional directories and files that became
obsolete over time. This change is more aligned to other architectures.

[Thomas: rebased on top of the "arch: improve definition of gcc mtune,
mcpu, etc." patch].

Signed-off-by: Chris Zankel <chris@zankel.net>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

arch/Config.in

@@ -145,6 +145,13 @@ config BR2_x86_64
 	  architecture compatible microprocessor).
 	  http://en.wikipedia.org/wiki/X86_64
 
+config BR2_xtensa
+	bool "Xtensa"
+	help
+	  Xtensa is a Tensilica processor IP architecture.
+	  http://en.wikipedia.org/wiki/Xtensa
+	  http://www.tensilica.com/
+
 endchoice
 
 # The following string values are defined by the individual
@@ -210,3 +217,7 @@ endif
 if BR2_i386 || BR2_x86_64
 source "arch/Config.in.x86"
 endif
+
+if BR2_xtensa
+source "arch/Config.in.xtensa"
+endif

arch/Config.in.xtensa

@@ -0,0 +1,2 @@
+config BR2_ARCH
+	default "xtensa"	if BR2_xtensa

linux/Config.in

@@ -152,7 +152,8 @@ config BR2_LINUX_KERNEL_BZIMAGE
 
 config BR2_LINUX_KERNEL_ZIMAGE
 	bool "zImage"
-	depends on BR2_arm || BR2_armeb || BR2_powerpc || BR2_sparc || BR2_sh || BR2_sh64
+	depends on BR2_arm || BR2_armeb || BR2_powerpc || BR2_sparc || \
+		   BR2_sh || BR2_sh64 || BR2_xtensa
 
 config BR2_LINUX_KERNEL_APPENDED_ZIMAGE
 	bool "zImage with appended DT"

package/ltrace/Config.in

@@ -1,6 +1,7 @@
 config BR2_PACKAGE_LTRACE
 	bool "ltrace"
 	depends on !(BR2_avr32 || BR2_mips || BR2_mipsel || BR2_sh || BR2_sh64)
+	depends on !BR2_xtensa
 	select BR2_PACKAGE_LIBELF
 	help
 	  Debugging program which runs a specified command until it exits.

toolchain/Config.in

@@ -23,7 +23,7 @@ config BR2_TOOLCHAIN_EXTERNAL
 
 config BR2_TOOLCHAIN_CTNG
 	bool "Crosstool-NG toolchain"
-	depends on !BR2_microblaze && !BR2_aarch64
+	depends on !BR2_microblaze && !BR2_aarch64 && !BR2_xtensa
 	select BR2_TOOLCHAIN_HAS_SHADOW_PASSWORDS
 	select BR2_TOOLCHAIN_HAS_THREADS_DEBUG_IF_NEEDED
 	help

toolchain/toolchain-buildroot/Config.in.2

@@ -68,7 +68,7 @@ config BR2_TOOLCHAIN_BUILDROOT_USE_SSP
 
 choice
 	prompt "Thread library implementation"
-	default BR2_PTHREADS_NATIVE if (!BR2_UCLIBC_VERSION_0_9_31) && !BR2_ARM_OABI
+	default BR2_PTHREADS_NATIVE if (!BR2_UCLIBC_VERSION_0_9_31) && !BR2_ARM_OABI && !BR2_xtensa
 	default BR2_PTHREADS_OLD
 	help
 	  Use this option to select the thread library implementation
@@ -82,6 +82,7 @@ choice
 
 	config BR2_PTHREADS
 		bool "linuxthreads"
+		depends on !BR2_xtensa
 	        select BR2_TOOLCHAIN_HAS_THREADS
 
 	config BR2_PTHREADS_OLD
@@ -94,6 +95,7 @@ choice
 		depends on !BR2_UCLIBC_VERSION_0_9_31
 		depends on !BR2_ARM_OABI
 		depends on !BR2_x86_i386
+		depends on !BR2_xtensa
 endchoice
 
 source "toolchain/elf2flt/Config.in"

toolchain/toolchain-common.in

@@ -93,7 +93,7 @@ config BR2_NEEDS_GETTEXT_IF_LOCALE
 	default y if (BR2_NEEDS_GETTEXT && BR2_ENABLE_LOCALE)
 
 config BR2_USE_MMU
-	bool "Enable MMU support" if BR2_arm || BR2_armeb || BR2_mips || BR2_mipsel || BR2_sh
+	bool "Enable MMU support" if BR2_arm || BR2_armeb || BR2_mips || BR2_mipsel || BR2_sh || BR2_xtensa
 	default y if !BR2_bfin
 	help
 	  If your target has a MMU, you should say Y here.  If you

toolchain/uClibc/Config.in

@@ -12,14 +12,15 @@ choice
 
 	config BR2_UCLIBC_VERSION_0_9_31
 		bool "uClibc 0.9.31.x"
+		depends on !BR2_xtensa
 
 	config BR2_UCLIBC_VERSION_0_9_32
 		bool "uClibc 0.9.32.x"
-		depends on !(BR2_avr32 || BR2_sh)
+		depends on !(BR2_avr32 || BR2_sh || BR2_xtensa)
 
 	config BR2_UCLIBC_VERSION_0_9_33
 		bool "uClibc 0.9.33.x"
-		depends on !BR2_avr32
+		depends on !(BR2_avr32 || BR2_xtensa)
 
 	config BR2_UCLIBC_VERSION_SNAPSHOT
 		bool "daily snapshot"

toolchain/uClibc/uclibc.mk

@@ -38,6 +38,7 @@ UCLIBC_TARGET_ARCH:=$(shell $(SHELL) -c "echo $(ARCH) | sed \
 		-e 's/sh[234].*/sh/' \
 		-e 's/mips.*/mips/' \
 		-e 's/cris.*/cris/' \
+		-e 's/xtensa.*/xtensa/' \
 ")
 
 UCLIBC_TARGET_ENDIAN:=$(call qstrip,$(BR2_ENDIAN))