[Buildroot] [PATCH v2] csky_gx6605s_defconfig: bump gcc to 6.3.0, kernel to 4.9.56

[Julien Olivain]

This patch updates the csky custom external toolchain to fix a broken
host dependency of gdb on libexpat.so.0 (most hosts now ship
libexpat.so.1). gdb is required to copy and and boot the kernel
(see board/csky/readme.txt). The updated gdb does no longer have this
host dependency, which solve the issue.

Since this external toolchain was built and tested with csky kernel
4.9.56, this patch also update to that kernel version.

Finally, this 4.9.56 csky kernel changed its default bootargs. So we
add a patch to preserve the same behavior as the previous version.

Signed-off-by: Julien Olivain <juju at cotds.org>
---
Changes v1 -> v2:
- explain why the update is needed in the commit log
---
 ...ine-for-serial-console-and-rootfs-on.patch | 25 +++++++++++++++++++
 configs/csky_gx6605s_defconfig                |  7 +++---
 2 files changed, 29 insertions(+), 3 deletions(-)
 create mode 100644 board/csky/gx6605s/patches/linux/0001-csky-update-cmdline-for-serial-console-and-rootfs-on.patch

diff --git a/board/csky/gx6605s/patches/linux/0001-csky-update-cmdline-for-serial-console-and-rootfs-on.patch b/board/csky/gx6605s/patches/linux/0001-csky-update-cmdline-for-serial-console-and-rootfs-on.patch
new file mode 100644
index 0000000000..1da1a75400
--- /dev/null
+++ b/board/csky/gx6605s/patches/linux/0001-csky-update-cmdline-for-serial-console-and-rootfs-on.patch
@@ -0,0 +1,25 @@
+From 7e3f2c482bc16537a093e87a27f0d465804a88e4 Mon Sep 17 00:00:00 2001
+From: Julien Olivain <juju at cotds.org>
+Date: Tue, 11 Dec 2018 23:04:46 +0100
+Subject: [PATCH] csky: update cmdline for serial console and rootfs on sda1
+
+Signed-off-by: Julien Olivain <juju at cotds.org>
+---
+ arch/csky/boot/dts/gx6605s.dts | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/arch/csky/boot/dts/gx6605s.dts b/arch/csky/boot/dts/gx6605s.dts
+index ce56106af967..f5d60b21e6f9 100644
+--- a/arch/csky/boot/dts/gx6605s.dts
++++ b/arch/csky/boot/dts/gx6605s.dts
+@@ -155,6 +155,6 @@
+ 	};
+ 
+ 	chosen {
+-		bootargs = "console=tty0 init=/sbin/init root=/dev/sda2 rw rootwait";
++		bootargs = "console=ttyS0,115200 init=/sbin/init root=/dev/sda1 rw rootwait";
+ 	};
+ };
+-- 
+2.19.2
+
diff --git a/configs/csky_gx6605s_defconfig b/configs/csky_gx6605s_defconfig
index 5f39c536ac..d0a2aadc6d 100644
--- a/configs/csky_gx6605s_defconfig
+++ b/configs/csky_gx6605s_defconfig
@@ -1,8 +1,9 @@
 BR2_csky=y
+BR2_GLOBAL_PATCH_DIR="board/csky/gx6605s/patches"
 BR2_TOOLCHAIN_EXTERNAL_DOWNLOAD=y
-BR2_TOOLCHAIN_EXTERNAL_URL="https://github.com/c-sky/tools/raw/master/csky-linux-tools-x86_64-glibc-linux-4.9.2-20170227.tar.gz"
+BR2_TOOLCHAIN_EXTERNAL_URL="https://github.com/c-sky/tools/raw/master/csky-linux-tools-x86_64-glibc-linux-4.9.56-20180128.tar.gz"
 BR2_TOOLCHAIN_EXTERNAL_CUSTOM_PREFIX="csky-linux"
-BR2_TOOLCHAIN_EXTERNAL_GCC_4_5=y
+BR2_TOOLCHAIN_EXTERNAL_GCC_6=y
 BR2_TOOLCHAIN_EXTERNAL_HEADERS_4_9=y
 BR2_TOOLCHAIN_EXTERNAL_CUSTOM_GLIBC=y
 BR2_TOOLCHAIN_EXTERNAL_CXX=y
@@ -10,7 +11,7 @@ BR2_TOOLCHAIN_EXTERNAL_GDB_SERVER_COPY=y
 BR2_TARGET_GENERIC_GETTY_PORT="ttyS0"
 BR2_LINUX_KERNEL=y
 BR2_LINUX_KERNEL_CUSTOM_TARBALL=y
-BR2_LINUX_KERNEL_CUSTOM_TARBALL_LOCATION="https://github.com/c-sky/linux-4.9.y/archive/314c498ddc8c43a66ca96ff3af7da98e10fa1cc6.tar.gz"
+BR2_LINUX_KERNEL_CUSTOM_TARBALL_LOCATION="https://github.com/c-sky/linux-4.9.y/archive/6064a9bdf48cefbccc4f6472dd04251f0dec1931.tar.gz"
 BR2_LINUX_KERNEL_DEFCONFIG="gx66xx"
 BR2_LINUX_KERNEL_DTS_SUPPORT=y
 BR2_LINUX_KERNEL_INTREE_DTS_NAME="gx6605s"
-- 
2.19.2