[M] Change in coreboot[master]: lib: Hook up libhwbase in romstage

[Jérémy Compostella (Code Review)]

Jérémy Compostella has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/70275 )

Change subject: lib: Hook up libhwbase in romstage
......................................................................

lib: Hook up libhwbase in romstage

It's hidden behind the configuration option `CONFIG_ROMSTAGE_LIBHWBASE'.

This also adds some glue code to use the coreboot console for debug
output and our monotonic timer framework as timer backend.

Running Ada code in romstage and more particular libhwbase brings a few
challenges as global initialized variables are not supported in
Cache-As-Ram mode.

1. The libhwbase dynamic mmio driver implementation makes the Gnat
   compiler generate some global initialized variables.

For this reason, when compiled for romstage or for romstage and
   ramstage the static mmio driver is enforced (`HWBASE_STATIC_MMIO').

2. The Gnat compiler generates elaboration functions to initialize
   program data at runtime. These elaboration functions are called by
   the romstage_adainit() function.

The data references symbols suffixed by `_E'. Even though these
   symbols, at compilation time, do not contain any data and are
   filled with zeros, the Gnat compiler installs them in the .data
   section.

Since these symbols are actually filled with zeros, it is safe to
   install them in the .bss section.

cf. https://docs.adacore.com/gnat_ugn-docs/html/gnat_ugn/gnat_ugn/elaboration_or...

This patch requires the libhwbase
https://review.coreboot.org/c/libhwbase/+/69854 CL.

BUG=b:252792591
BRANCH=firmware-brya-14505.B
TEST=TO-BE-COMPLETED

Change-Id: I670249d33506e886a683e55d1589cb2bf9b16aa3
Signed-off-by: Jeremy Compostella 
---
M src/arch/x86/car.ld
M src/console/Makefile.inc
M src/lib/Kconfig
M src/lib/Makefile.inc
4 files changed, 85 insertions(+), 8 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/75/70275/1

diff --git a/src/arch/x86/car.ld b/src/arch/x86/car.ld
index 47afd78..dc075c6 100644
--- a/src/arch/x86/car.ld
+++ b/src/arch/x86/car.ld
@@ -67,6 +67,12 @@
    *(.bss.*)
    *(.sbss)
    *(.sbss.*)
+	/* '*_E' GNAT generated global variables actually are un-initialized
+	 * (filled with zeros) variables which are initialized at
+	 * runtime. Therefore, they can be placed in the _bss region. */
+#if CONFIG(ROMSTAGE_LIBHWBASE)
+	*(.data.hw__*_E)
+#endif
    . = ALIGN(ARCH_POINTER_ALIGN_SIZE);
    _ebss = .;
    RECORD_SIZE(bss)
diff --git a/src/console/Makefile.inc b/src/console/Makefile.inc
index e2a20d7..4296426 100644
--- a/src/console/Makefile.inc
+++ b/src/console/Makefile.inc
@@ -5,6 +5,8 @@
 ifeq ($(CONFIG_HWBASE_DEBUG_CB),y)
 ramstage-$(CONFIG_RAMSTAGE_LIBHWBASE) += hw-debug_sink.ads
 ramstage-$(CONFIG_RAMSTAGE_LIBHWBASE) += hw-debug_sink.adb
+romstage-$(CONFIG_ROMSTAGE_LIBHWBASE) += hw-debug_sink.ads
+romstage-$(CONFIG_ROMSTAGE_LIBHWBASE) += hw-debug_sink.adb
 endif

smm-$(CONFIG_DEBUG_SMI) += init.c console.c vtxprintf.c printk.c
diff --git a/src/lib/Kconfig b/src/lib/Kconfig
index 96181c9..837d8ac 100644
--- a/src/lib/Kconfig
+++ b/src/lib/Kconfig
@@ -21,6 +21,12 @@
    help
      Selected by features that require `libhwbase` in ramstage.

+config ROMSTAGE_LIBHWBASE
+	bool
+	select ROMSTAGE_ADA
+	help
+	  Selected by features that require `libhwbase` in romstage.
+
 config FLATTENED_DEVICE_TREE
    bool
    help
@@ -68,11 +74,22 @@
    help
      Name of the FMAP region created in the default FMAP to cache SPD data.

-if RAMSTAGE_LIBHWBASE
+if RAMSTAGE_LIBHWBASE && !ROMSTAGE_LIBHWBASE

config HWBASE_DYNAMIC_MMIO
    def_bool y

+endif
+
+if ROMSTAGE_LIBHWBASE
+
+config HWBASE_STATIC_MMIO
+	def_bool y
+
+endif
+
+if RAMSTAGE_LIBHWBASE || ROMSTAGE_LIBHWBASE
+
 config HWBASE_DEFAULT_MMCONF
    hex
    default ECAM_MMCONF_BASE_ADDRESS
diff --git a/src/lib/Makefile.inc b/src/lib/Makefile.inc
index 600c6dc..6897ac5 100644
--- a/src/lib/Makefile.inc
+++ b/src/lib/Makefile.inc
@@ -342,28 +342,34 @@
 ramstage-$(CONFIG_RAMSTAGE_ADA) += cb.ads
 romstage-$(CONFIG_ROMSTAGE_ADA) += cb.ads

-ifeq ($(CONFIG_RAMSTAGE_LIBHWBASE),y)
+ifneq (,$(filter y, $(CONFIG_RAMSTAGE_LIBHWBASE) $(CONFIG_ROMSTAGE_LIBHWBASE)))

to-ada-hex = $(eval $(1) := 16\#$(patsubst 0x%,%,$($(1)))\#)

$(call to-ada-hex,CONFIG_HWBASE_DEFAULT_MMCONF)

+libhwbase-stages = $(foreach stage, romstage ramstage, \
+	$(if $(filter y,$(CONFIG_$(call toupper,$(stage))_LIBHWBASE)),$(stage)))
+
 $(call add-special-class,hw)
-hw-handler = $(eval ramstage-srcs += $$(addprefix $(1),$(2)))
+hw-handler +=$(foreach stage, $(libhwbase-stages), \
+	$(eval $(stage)-srcs += $$(addprefix $(1),$(2))))

$(call add-special-class,hw-gen)
 hw-gen-handler = \
    $(eval additional-dirs += $(dir $(2))) \
-	$(eval ramstage-srcs += $(2)) \
-	$(eval ramstage-ads-deps += $(2)) \
-	$(eval ramstage-adb-deps += $(2)) \
+	$(foreach stage, $(libhwbase-stages), \
+		$(eval $(stage)-srcs += $(2)) \
+		$(eval $(stage)-ads-deps += $(2)) \
+		$(eval $(stage)-adb-deps += $(2))) \
    $(eval $(2): $(obj)/config.h)

subdirs-y += ../../3rdparty/libhwbase

-ramstage-$(CONFIG_HAVE_MONOTONIC_TIMER) += hw-time-timer.adb
+$(foreach stage,$(libhwbase-stages), \
+	$(eval $(stage)-$(CONFIG_HAVE_MONOTONIC_TIMER) += hw-time-timer.adb))

-endif # CONFIG_RAMSTAGE_LIBHWBASE
+endif # CONFIG_ROMSTAGE_LIBHWBASE || CONFIG_RAMSTAGE_LIBHWBASE

romstage-y += spd_bin.c