[Buildroot] [PATCH v5 1/3] uboot: zynqmp: generate SPL image with PMUFW binary

[Luca Ceresoli <luca@lucaceresoli.net>]

In order to boot on the Xilinx ZynqMP SoCs, U-Boot SPL requires a
recent PMU firmware loaded. Instruct U-Boot to add pmufw.bin to the
boot.bin file together with U-Boot SPL, and the boot ROM will load
both.

For this to work properly, a patch to U-Boot is needed. However this
patch must be applied by each defconfig that wishes to use
BR2_TARGET_UBOOT_ZYNQMP_PMUFW. If it were in boot/uboot/ to be applied
unconditionally, it would break the build for configs using a U-Boot
version higher than 2018.7-rc1 where the patch is already applied.

Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
Cc: Joel Carlson <joelsoncarl@gmail.com>

---
Changes v4 -> v5:
 - accept either a path (absolute or relative) or an URL to be
   downloaded
 - moved before "uboot: zynqmp: allow to use custom psu_init files"

Changes v3 -> v4:
 - don't copy the pmufw binary in the source tree, use an absolute path
   to the download dir (which needs a patch from upstream to work)
 - depend on BR2_TARGET_UBOOT_BUILD_SYSTEM_KCONFIG (Thomas)

Changes v2 -> v3:
 - don't use a "zynqmp-pmufw-binaries" package, just download a file
 - define kconfig fixups in a variable, then define
   UBOOT_KCONFIG_FIXUP_CMDS unconditionally at global scope (Thomas)
 - use $(INSTALL), not cp (Thomas)
 - $(...) instead of ${...} to reference make variables (Thomas)

Changes v1 -> v2:
 - split from a larger patch doing 2 things.
---
 ...ept-an-absolute-path-for-PMUFW_INIT_.patch | 68 +++++++++++++++++++
 boot/uboot/Config.in                          | 29 ++++++++
 boot/uboot/uboot.mk                           | 24 +++++++
 3 files changed, 121 insertions(+)
 create mode 100644 board/zynqmp/patches/uboot/0003-arm64-zynqmp-accept-an-absolute-path-for-PMUFW_INIT_.patch

diff --git a/board/zynqmp/patches/uboot/0003-arm64-zynqmp-accept-an-absolute-path-for-PMUFW_INIT_.patch b/board/zynqmp/patches/uboot/0003-arm64-zynqmp-accept-an-absolute-path-for-PMUFW_INIT_.patch
new file mode 100644
index 000000000000..95ab7b3b75ca
--- /dev/null
+++ b/board/zynqmp/patches/uboot/0003-arm64-zynqmp-accept-an-absolute-path-for-PMUFW_INIT_.patch
@@ -0,0 +1,68 @@
+From c7df098a71e05dc81cee818747759e8060b59626 Mon Sep 17 00:00:00 2001
+From: Luca Ceresoli <luca@lucaceresoli.net>
+Date: Mon, 4 Jun 2018 12:21:01 +0200
+Subject: [PATCH] arm64: zynqmp: accept an absolute path for PMUFW_INIT_FILE
+
+The value of PMUFW_INIT_FILE is prefixed with "$(srctree)/", thus
+forcing it to be a relative path inside the U-Boot source tree. Since
+the PMUFW is a binary file generated outside of U-Boot, the PMUFW
+binary must be copied inside the U-Boot source tree before the
+build.
+
+This generates a few problems:
+
+ * if the source tree is shared among different out-of-tree builds,
+   they will pollute (and potentially corrupt) each other
+ * the source tree cannot be read-only
+ * any buildsystem must add a command to copy the PMUFW binary
+ * putting an externally-generated binary in the source tree is ugly
+   as hell
+
+Avoid these problems by accepting an absolute path for
+PMUFW_INIT_FILE. This would be as simple as removing the "$(srctree)/"
+prefix, but in order to keep backward compatibility we rather use the
+shell and readlink to get the absolute path even when starting from a
+relative path.
+
+Since 'readlink -f' produces an empty string if the file does not
+exist, we also add a check to ensure the file configured in
+PMUFW_INIT_FILE exists. Otherwise the build would exit successfully,
+but produce a boot.bin without PMUFW as if PMUFW_INIT_FILE were empty.
+
+Tested in the 12 possible combinations of:
+ - PMUFW_INIT_FILE empty, relative, absolute, non-existing
+ - building in-tree, in subdir, in other directory
+
+Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
+Cc: Michal Simek <michal.simek@xilinx.com>
+Cc: Simon Glass <sjg@chromium.org>
+Cc: Emmanuel Vadot <manu@bidouilliste.com>
+Signed-off-by: Michal Simek <michal.simek@xilinx.com>
+Backported from upstream: https://git.denx.de/?p=u-boot.git;a=commit;h=c7df098a71e05dc81cee818747759e8060b59626
+---
+ scripts/Makefile.spl | 8 +++++++-
+ 1 file changed, 7 insertions(+), 1 deletion(-)
+
+diff --git a/scripts/Makefile.spl b/scripts/Makefile.spl
+index ef018b5b4056..252f13826d4c 100644
+--- a/scripts/Makefile.spl
++++ b/scripts/Makefile.spl
+@@ -167,8 +167,14 @@ ifdef CONFIG_ARCH_ZYNQ
+ MKIMAGEFLAGS_boot.bin = -T zynqimage -R $(srctree)/$(CONFIG_BOOT_INIT_FILE)
+ endif
+ ifdef CONFIG_ARCH_ZYNQMP
++ifneq ($(CONFIG_PMUFW_INIT_FILE),"")
++spl/boot.bin: zynqmp-check-pmufw
++zynqmp-check-pmufw: FORCE
++	( cd $(srctree) && test -r $(CONFIG_PMUFW_INIT_FILE) ) \
++		|| ( echo "Cannot read $(CONFIG_PMUFW_INIT_FILE)" && false )
++endif
+ MKIMAGEFLAGS_boot.bin = -T zynqmpimage -R $(srctree)/$(CONFIG_BOOT_INIT_FILE) \
+-	-n $(srctree)/$(CONFIG_PMUFW_INIT_FILE)
++	-n "$(shell cd $(srctree); readlink -f $(CONFIG_PMUFW_INIT_FILE))"
+ endif
+ 
+ spl/boot.bin: $(obj)/u-boot-spl.bin FORCE
+-- 
+2.7.4
+
diff --git a/boot/uboot/Config.in b/boot/uboot/Config.in
index 7f8291abe894..a4aeefc7ae16 100644
--- a/boot/uboot/Config.in
+++ b/boot/uboot/Config.in
@@ -368,6 +368,35 @@ config BR2_TARGET_UBOOT_ZYNQ_IMAGE
 	  for u-boot-dtb.img file so this U-Boot format is required
 	  to be set.
 
+config BR2_TARGET_UBOOT_ZYNQMP
+	bool "Boot on the Xilinx ZynqMP SoCs"
+	depends on BR2_aarch64
+	help
+	  Enable options specific to the Xilinx ZynqMP family of SoCs.
+
+if BR2_TARGET_UBOOT_ZYNQMP
+
+config BR2_TARGET_UBOOT_ZYNQMP_PMUFW
+	string "PMU firmware location"
+	depends on BR2_TARGET_UBOOT_BUILD_SYSTEM_KCONFIG
+	help
+	  Location of a PMU firmware binary.
+
+	  If not empty, instructs the U-Boot build process to generate
+	  a boot.bin (to be loaded by the ZynqMP boot ROM) containing
+	  both the U-Boot SPL and the PMU firmware in the
+	  Xilinx-specific boot format.
+
+	  The value can be an absolute or relative path, and will be
+	  used directly from where it is located, or an URI
+	  (e.g. http://...), and it will be downloaded and used from
+	  the download directory.
+
+	  If empty, the generated boot.bin will not contain a PMU
+	  firmware.
+
+endif
+
 config BR2_TARGET_UBOOT_ALTERA_SOCFPGA_IMAGE_CRC
 	bool "CRC image for Altera SoC FPGA (mkpimage)"
 	depends on BR2_arm
diff --git a/boot/uboot/uboot.mk b/boot/uboot/uboot.mk
index bf227f28934f..53da0f39594b 100644
--- a/boot/uboot/uboot.mk
+++ b/boot/uboot/uboot.mk
@@ -287,6 +287,26 @@ define UBOOT_INSTALL_IMAGES_CMDS
 			$(BINARIES_DIR)/boot.scr)
 endef
 
+ifeq ($(BR2_TARGET_UBOOT_ZYNQMP),y)
+
+UBOOT_ZYNQMP_PMUFW = $(call qstrip,$(BR2_TARGET_UBOOT_ZYNQMP_PMUFW))
+
+ifneq ($(findstring ://,$(UBOOT_ZYNQMP_PMUFW)),)
+UBOOT_EXTRA_DOWNLOADS += $(UBOOT_ZYNQMP_PMUFW)
+BR_NO_CHECK_HASH_FOR += $(notdir $(UBOOT_ZYNQMP_PMUFW))
+define UBOOT_ZYNQMP_KCONFIG_PMUFW
+	$(call KCONFIG_SET_OPT,CONFIG_PMUFW_INIT_FILE,"$(UBOOT_DL_DIR)/$(notdir $(UBOOT_ZYNQMP_PMUFW))", \
+	       $(@D)/.config)
+endef
+else ifneq ($(UBOOT_ZYNQMP_PMUFW),)
+define UBOOT_ZYNQMP_KCONFIG_PMUFW
+	$(call KCONFIG_SET_OPT,CONFIG_PMUFW_INIT_FILE,"$(shell readlink -f $(UBOOT_ZYNQMP_PMUFW))", \
+	       $(@D)/.config)
+endef
+endif
+
+endif # BR2_TARGET_UBOOT_ZYNQMP
+
 define UBOOT_INSTALL_OMAP_IFT_IMAGE
 	cp -dpf $(@D)/$(UBOOT_BIN_IFT) $(BINARIES_DIR)/
 endef
@@ -336,6 +356,10 @@ UBOOT_DEPENDENCIES += host-mkpimage
 UBOOT_POST_INSTALL_IMAGES_HOOKS += UBOOT_CRC_ALTERA_SOCFPGA_IMAGE
 endif
 
+define UBOOT_KCONFIG_FIXUP_CMDS
+	$(UBOOT_ZYNQMP_KCONFIG_PMUFW)
+endef
+
 ifeq ($(BR2_TARGET_UBOOT_ENVIMAGE),y)
 ifeq ($(BR_BUILDING),y)
 ifeq ($(call qstrip,$(BR2_TARGET_UBOOT_ENVIMAGE_SOURCE)),)
-- 
2.17.1