linux: add support of Synopsys ARC770-based boards

This patch introduces support of new boards with ARC cores.

 [1] Synopsys SDP board
     This is a new-generation development board from Synopsys that
     consists of base-board and CPU tile-board (which might have a real
     ASIC or FPGA with CPU image).
     It sports a lot of DesignWare peripherals like GMAC, USB, SPI, I2C
     etc and is intended to be used for early development of ARC-based
     products.

 [2] nSIM
     This is a virtual board implemented in Synopsys proprietary
     software simulator (even though available for free for open source
     community). This board has only serial port as a peripheral and so
     it is meant to be used for runtime testing which is especially
     useful during bring-up of new tools and platforms.
     What's also important ARC cores are very configurable so there're
     many variations of options like cache sizes, their line lengths,
     additional hardware blocks like multipliers, dividers etc. And this
     board could be used to make sure built software still runs on
     different HW configurations.

Cc: Felix Fietkau <nbd@openwrt.org>
Cc: Jo-Philipp Wich <jow@openwrt.org>
Cc: Jonas Gorski <jogo@openwrt.org>
Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>

SVN-Revision: 47589

1 files changed, 36 insertions, 0 deletions

diff --git a/target/linux/arc770/patches-4.3/0001-openwrt-arc-remove-dependency-on-DEVTMPFS.patch b/target/linux/arc770/patches-4.3/0001-openwrt-arc-remove-dependency-on-DEVTMPFS.patch
new file mode 100644
index 0000000000..53f80749bd
--- /dev/null
+++ b/target/linux/arc770/patches-4.3/0001-openwrt-arc-remove-dependency-on-DEVTMPFS.patch
@@ -0,0 +1,36 @@
+From 271777096a31e76b2ffd750bc44efde9656de857 Mon Sep 17 00:00:00 2001
+From: Alexey Brodkin <abrodkin@synopsys.com>
+Date: Thu, 13 Aug 2015 01:56:02 +0300
+Subject: [PATCH] openwrt: arc - remove dependency on DEVTMPFS
+
+OpenWRT builds initramfs so that it doesn't require DEVTMPFS so dropping
+this dependency. That helps to escape 2 separate kernel rebuilds with
+and without initramfs.
+
+2 builds happen because OpenWRT first builds kernel and later modules.
+When building entire kernel with simple "make" INITRAMFS sets to a real
+value and so was triggering DEVTMPFS selection. Then when building only
+modules with "make modules" command INITRAMFS is zeroed and so kernel
+config was changing that lead to full kernel rebuild.
+
+Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
+---
+ arch/arc/Kconfig | 2 --
+ 1 file changed, 2 deletions(-)
+
+diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
+index cf96ef2..f0c6d4c 100644
+--- a/arch/arc/Kconfig
++++ b/arch/arc/Kconfig
+@@ -11,8 +11,6 @@ config ARC
+ 	select BUILDTIME_EXTABLE_SORT
+ 	select COMMON_CLK
+ 	select CLONE_BACKWARDS
+-	# ARC Busybox based initramfs absolutely relies on DEVTMPFS for /dev
+-	select DEVTMPFS if !INITRAMFS_SOURCE=""
+ 	select GENERIC_ATOMIC64
+ 	select GENERIC_CLOCKEVENTS
+ 	select GENERIC_FIND_FIRST_BIT
+-- 
+2.4.3
+