configs/imx6ullevk: bump Linux to 6.18.8 and U-Boot to 2026.01

The patch:
* bumps Linux kernel to version 6.18.8
* bumps U-Boot to version 2026.01
* forces check hashes
* create a board/freescale/imx6ull-evk folder dedicated to upstream Linux
  and U-Boot to ease maintainance.
* clean up both imx6ullevk and imx6ull-evk readme.txt files

Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com>
[Julien: fix IMX6ULLQSG url in readme.txt]
Signed-off-by: Julien Olivain <ju.o@free.fr>

.checkpackageignore

@@ -103,7 +103,6 @@ configs/imx6-sabresd_qt5_defconfig lib_defconfig.ForceCheckHash
 configs/imx6slevk_defconfig lib_defconfig.ForceCheckHash
 configs/imx6sx-sdb_defconfig lib_defconfig.ForceCheckHash
 configs/imx6ulevk_defconfig lib_defconfig.ForceCheckHash
-configs/imx6ullevk_defconfig lib_defconfig.ForceCheckHash
 configs/imx6ulpico_defconfig lib_defconfig.ForceCheckHash
 configs/imx7dpico_defconfig lib_defconfig.ForceCheckHash
 configs/imx8mqevk_defconfig lib_defconfig.ForceCheckHash

board/freescale/imx6ull-evk/linux_sdma.fragment

@@ -0,0 +1 @@
+CONFIG_IMX_SDMA=m

board/freescale/imx6ull-evk/patches/linux-headers/linux-headers.hash

@@ -0,0 +1 @@
+../linux/linux.hash

board/freescale/imx6ull-evk/patches/linux/linux.hash

@@ -0,0 +1,2 @@
+# Locally calculated
+sha256  37f0c5d5c242c1d604e87d48f08795e861a5a85f725b4ca11d0a538f12ff8cff  linux-6.18.8.tar.xz

board/freescale/imx6ull-evk/patches/uboot/uboot.hash

@@ -0,0 +1,2 @@
+# Locally calculated
+sha256  b60d5865cefdbc75da8da4156c56c458e00de75a49b80c1a2e58a96e30ad0d54  u-boot-2026.01.tar.bz2

board/freescale/imx6ull-evk/readme.txt

@@ -0,0 +1,64 @@
+****************************
+Freescale i.MX6ULL EVK board
+****************************
+
+This file documents the Buildroot support for the Freescale i.MX6ULL EVK board
+using Upstream U-Boot and Linux.
+
+Build
+=====
+
+First, configure Buildroot for your i.MX6ULL EVK board:
+
+In order to do so issue:
+
+  make imx6ullevk_defconfig
+
+Build all components:
+
+  make
+
+You will find in output/images/ the following files:
+  - boot.vfat
+  - imx6ull-14x14-evk.dtb
+  - rootfs.ext2
+  - rootfs.ext4
+  - rootfs.tar
+  - sdcard.img
+  - u-boot.bin
+  - u-boot-dtb.imx
+  - zImage
+
+Create a bootable SD card
+=========================
+
+To determine the device associated to the SD card have a look in the
+/proc/partitions file:
+
+  cat /proc/partitions
+
+Buildroot prepares a bootable "sdcard.img" image in the output/images/
+directory, ready to be dumped on a SD card. Launch the following
+command as root:
+
+  dd if=./output/images/sdcard.img of=/dev/<your-sd-device>
+
+*** WARNING! This will destroy all the card content. Use with care! ***
+
+For details about the medium image layout, see the definition in
+board/freescale/common/imx/genimage.cfg.template.
+
+Boot the i.MX6ULL EVK board
+===========================
+
+To boot your newly created system (refer to the i.MX 6ULL EVK Quick Start Guide [1] for guidance):
+- insert the SD card in the micro SD slot of the board;
+- put a micro USB cable into the Debug USB Port and connect using a terminal
+  emulator at 115200 bps, 8n1;
+- power on the board.
+
+Enjoy!
+
+References
+==========
+[1] https://www.nxp.com/webapp/Download?colCode=IMX6ULLQSG

board/freescale/imx6ullevk/readme.txt

@@ -2,25 +2,18 @@
 Freescale i.MX6ULL EVK board
 ****************************
 
-This file documents the Buildroot support for the Freescale i.MX6ULL EVK board.
+This file documents the Buildroot support for the Freescale i.MX6ULL EVK board
+using Vendor U-Boot and Linux.
 
 Build
 =====
 
 First, configure Buildroot for your i.MX6ULL EVK board:
 
-In order to do so there are two supported options:
+In order to do so issue:
 
   make freescale_imx6ullevk_defconfig
 
-if you plan to use NXP provided U-Boot and kernel.
-
-or
-
-  make imx6ullevk_defconfig
-
-if you plan to use mainline U-Boot and mainline kernel.
-
 Build all components:
 
   make

configs/imx6ullevk_defconfig

@@ -1,13 +1,15 @@
 BR2_arm=y
 BR2_cortex_a7=y
 BR2_ARM_FPU_NEON_VFPV4=y
-BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_6_6=y
+BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_6_18=y
+BR2_GLOBAL_PATCH_DIR="board/freescale/imx6ull-evk/patches"
+BR2_DOWNLOAD_FORCE_CHECK_HASHES=y
 BR2_ROOTFS_DEVICE_CREATION_DYNAMIC_EUDEV=y
 BR2_TARGET_GENERIC_GETTY_PORT="ttymxc0"
 BR2_ROOTFS_POST_IMAGE_SCRIPT="board/freescale/common/imx/post-image.sh"
 BR2_LINUX_KERNEL=y
 BR2_LINUX_KERNEL_CUSTOM_VERSION=y
-BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="6.6.4"
+BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="6.18.8"
 BR2_LINUX_KERNEL_DEFCONFIG="imx_v6_v7"
 BR2_LINUX_KERNEL_DTS_SUPPORT=y
 BR2_LINUX_KERNEL_INTREE_DTS_NAME="nxp/imx/imx6ull-14x14-evk"
@@ -20,9 +22,10 @@ BR2_TARGET_ROOTFS_EXT2_4=y
 BR2_TARGET_UBOOT=y
 BR2_TARGET_UBOOT_BOARDNAME="mx6ull_14x14_evk"
 BR2_TARGET_UBOOT_CUSTOM_VERSION=y
-BR2_TARGET_UBOOT_CUSTOM_VERSION_VALUE="2023.10"
+BR2_TARGET_UBOOT_CUSTOM_VERSION_VALUE="2026.01"
 BR2_TARGET_UBOOT_NEEDS_DTC=y
 BR2_TARGET_UBOOT_NEEDS_OPENSSL=y
+BR2_TARGET_UBOOT_NEEDS_GNUTLS=y
 BR2_TARGET_UBOOT_FORMAT_DTB_IMX=y
 BR2_PACKAGE_HOST_DOSFSTOOLS=y
 BR2_PACKAGE_HOST_GENIMAGE=y