boot/uboot: add support for custom zynq ps7_init_gpl.c

On Zynq, the booloader is responsible for some basic initializations, such as
enabling peripherals, DDR and configuring pinmuxes. The ps7_init_gpl.c file
(and optionally, ps7_init_gpl.h) contains the code for such initializations.

Although U-Boot contains ps7_init_gpl.c files for some boards, each of them
describes only one specific configuration. Users of a different board, or
needing a different configuration, can generate custom files using the Xilinx
Vivado development tools.

This patch adds Buildroot support for custom zynq ps7_init_gpl.c files in the
same way that is already done for zynqmp when working with custom hardware
that is not already supported by u-boot.

To test this feature, the following configs can be added to any zynq_defconfig:

BR2_TARGET_UBOOT_ZYNQ=y
BR2_TARGET_UBOOT_ZYNQ_PS7_INIT_FILE=<path to custom board ps7_init_gpl.c>

Signed-off-by: Neal Frager <neal.frager@amd.com>
Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Reviewed-by: Brandon Maier <brandon.maier@collins.com>
Signed-off-by: Julien Olivain <ju.o@free.fr>

board/zynq/readme.txt

@@ -71,17 +71,18 @@ you need to add them by yourself.
 1) Start with a defconfig supported by Buildroot (e.g. Zedboard)
     make zynq_zed_defconfig
 
-2) make uboot-menuconfig
+2) make menuconfig
-    Visit the following menu and enable CONFIG_XILINX_PS_INIT_FILE
+    Visit the following menu to enable BR2_TARGET_UBOOT_ZYNQ
 
-    ARM architecture  --->
+    Bootloaders  --->
-       [*] Zynq/ZynqMP PS init file(s) location
+       U-Boot  --->
+           [*]   Boot on the Xilinx Zynq SoCs
 
-3) Copy ps7_init_gpl.c/h generated by the Xilinx Vivado tools into
+3) make menuconfig
-   output/build/uboot-custom/board/xilinx/zynq/custom_hw_platform/
+    In the same menu, configure BR2_TARGET_UBOOT_ZYNQ_PS7_INIT_FILE
+
+    Bootloaders  --->
+       U-Boot  --->
+          (<Path to ps7_init_gpl.c>) Custom ps7_init_gpl file
 
 4) make
-
-Note: The files in step 3 will need to be re-copied after cleaning the
-output directory and at this time, there is no way to save them as
-part of the buildroot configuration, except as a U-Boot patch.

boot/uboot/Config.in

@@ -701,6 +701,40 @@ config BR2_TARGET_UBOOT_ZYNQMP_PSU_INIT_FILE
 
 endif
 
+config BR2_TARGET_UBOOT_ZYNQ
+	bool "Boot on the Xilinx Zynq SoCs"
+	depends on BR2_arm
+	help
+	  Enable options specific to the Xilinx Zynq family of SoCs.
+
+config BR2_TARGET_UBOOT_ZYNQ_PS7_INIT_FILE
+	string "Custom ps7_init_gpl file"
+	depends on BR2_TARGET_UBOOT_BUILD_SYSTEM_KCONFIG
+	depends on BR2_TARGET_UBOOT_ZYNQ
+	help
+	  On Zynq the booloader is responsible for some basic
+	  initializations, such as enabling peripherals and
+	  configuring pinmuxes. The ps7_init_gpl.c file (and,
+	  optionally, ps7_init_gpl.h) contains the code for such
+	  initializations.
+
+	  Although U-Boot contains ps7_init_gpl.c files for some
+	  boards, each of them describes only one specific
+	  configuration. Users of a different board, or needing a
+	  different configuration, can generate custom files using
+	  the Xilinx Vivado development tools.
+
+	  Set this variable to the path to your ps7_init_gpl.c file
+	  (e.g. "board/myboard/ps7_init_gpl.c"). ps7_init_gpl.h, if
+	  needed, should be in the same directory. U-Boot will build
+	  and link the user-provided file instead of the built-in.
+
+	  Leave empty to use the files provided by U-Boot.
+
+	  This feature requires commit
+	  6da4f67ad09cd8b311d77b2b04e557b7ef65b56c from upstream
+	  U-Boot, available from versions after 2018.07.
+
 config BR2_TARGET_UBOOT_ALTERA_SOCFPGA_IMAGE_CRC
 	bool "CRC image for Altera SoC FPGA (mkpimage)"
 	depends on BR2_arm

boot/uboot/uboot.mk

@@ -520,6 +520,17 @@ endif
 
 endif # BR2_TARGET_UBOOT_ZYNQMP
 
+ifeq ($(BR2_TARGET_UBOOT_ZYNQ),y)
+UBOOT_ZYNQ_PS7_INIT = $(call qstrip,$(BR2_TARGET_UBOOT_ZYNQ_PS7_INIT_FILE))
+UBOOT_ZYNQ_PS7_INIT_PATH = $(shell readlink -f $(UBOOT_ZYNQ_PS7_INIT))
+
+ifneq ($(UBOOT_ZYNQ_PS7_INIT),)
+define UBOOT_ZYNQ_KCONFIG_PS7_INIT
+	$(call KCONFIG_SET_OPT,CONFIG_XILINX_PS_INIT_FILE,"$(UBOOT_ZYNQ_PS7_INIT_PATH)")
+endef
+endif
+endif # BR2_TARGET_UBOOT_ZYNQ
+
 define UBOOT_INSTALL_OMAP_IFT_IMAGE
 	cp -dpf $(@D)/$(UBOOT_BIN_IFT) $(BINARIES_DIR)/
 endef
@@ -562,6 +573,7 @@ define UBOOT_KCONFIG_FIXUP_CMDS
 	$(UBOOT_ZYNQMP_KCONFIG_PMUFW)
 	$(UBOOT_ZYNQMP_KCONFIG_PM_CFG)
 	$(UBOOT_ZYNQMP_KCONFIG_PSU_INIT)
+	$(UBOOT_ZYNQ_KCONFIG_PS7_INIT)
 	$(UBOOT_KCONFIG_DEFAULT_ENV_FILE)
 endef