From 6de59bdbc09ebc42fd10ee14cf3eb4dadec97b62 Mon Sep 17 00:00:00 2001
From: Michal Sieron <msieron@internships.antmicro.com>
Date: Fri, 23 Jul 2021 12:58:13 +0200
Subject: [PATCH] Incorporate picolibc into the build process

Right now it is still limited as it compiles only for one target,
but it should be possible to build BIOS with one command

Tested with digilent_arty.py
---
 litex/soc/integration/builder.py            |  5 +-
 litex/soc/software/libc/Makefile            |  7 +++
 litex/soc/software/libc/cross-rv32im.txt    | 18 +++++++
 litex/soc/software/libc/do-rv32im-configure | 11 ++++
 litex/soc/software/libc/swap_libc.sh        | 58 +++++++++++++++++++++
 5 files changed, 98 insertions(+), 1 deletion(-)
 create mode 100644 litex/soc/software/libc/Makefile
 create mode 100644 litex/soc/software/libc/cross-rv32im.txt
 create mode 100755 litex/soc/software/libc/do-rv32im-configure
 create mode 100644 litex/soc/software/libc/swap_libc.sh

diff --git a/litex/soc/integration/builder.py b/litex/soc/integration/builder.py
index 4633845dd..cc24531f4 100644
--- a/litex/soc/integration/builder.py
+++ b/litex/soc/integration/builder.py
@@ -41,6 +41,7 @@ soc_software_packages = [
 
     # LiteX cores.
     "libbase",
+    "libc",
 
     # LiteX Ecosystem cores.
     "libfatfs",
@@ -138,8 +139,10 @@ class Builder:
         for k, v in export.get_cpu_mak(self.soc.cpu, self.compile_software):
             define(k, v)
 
-        # Define the SoC/Compiler-RT/Software/Include directories.
+        # Define the SoC/Picolibc/Compiler-RT/Software/Include directories.
         define("SOC_DIRECTORY", soc_directory)
+        picolibc_directory = get_data_mod("software", "picolibc").data_location
+        define("PICOLIBC_DIRECTORY", picolibc_directory)
         compiler_rt_directory = get_data_mod("software", "compiler_rt").data_location
         define("COMPILER_RT_DIRECTORY", compiler_rt_directory)
         variables_contents.append("export BUILDINC_DIRECTORY")
diff --git a/litex/soc/software/libc/Makefile b/litex/soc/software/libc/Makefile
new file mode 100644
index 000000000..7f47e0299
--- /dev/null
+++ b/litex/soc/software/libc/Makefile
@@ -0,0 +1,7 @@
+include ../include/generated/variables.mak
+include $(SOC_DIRECTORY)/software/common.mak
+
+newlib/libc.a:
+	$(LIBC_DIRECTORY)/do-rv32im-configure $(PICOLIBC_DIRECTORY)
+	meson compile
+	sh $(LIBC_DIRECTORY)/swap_libc.sh
diff --git a/litex/soc/software/libc/cross-rv32im.txt b/litex/soc/software/libc/cross-rv32im.txt
new file mode 100644
index 000000000..15abc56ee
--- /dev/null
+++ b/litex/soc/software/libc/cross-rv32im.txt
@@ -0,0 +1,18 @@
+[binaries]
+c = 'riscv64-unknown-elf-gcc'
+ar = 'riscv64-unknown-elf-ar'
+as = 'riscv64-unknown-elf-as'
+nm = 'riscv64-unknown-elf-nm'
+strip = 'riscv64-unknown-elf-strip'
+
+[host_machine]
+system = 'unknown'
+cpu_family = 'riscv'
+cpu = 'riscv32'
+endian = 'little'
+
+[properties]
+c_args = [ '-nostdlib', '-mno-save-restore', '-march=rv32im', '-mabi=ilp32']
+c_link_args = [ '-nostdlib', '-mno-save-restore', '-march=rv32im', '-mabi=ilp32']
+skip_sanity_check = true
+
diff --git a/litex/soc/software/libc/do-rv32im-configure b/litex/soc/software/libc/do-rv32im-configure
new file mode 100755
index 000000000..64bf04d47
--- /dev/null
+++ b/litex/soc/software/libc/do-rv32im-configure
@@ -0,0 +1,11 @@
+#!/bin/sh
+
+ARCH=riscv64-unknown-elf
+DIR=`dirname $0`
+meson "$1" \
+        -Dtests=true \
+        -Dmultilib=false \
+        -Dincludedir="picolibc/$ARCH/include" \
+        -Dlibdir="picolibc/$ARCH/lib" \
+        --cross-file "$DIR/cross-rv32im.txt" \
+
diff --git a/litex/soc/software/libc/swap_libc.sh b/litex/soc/software/libc/swap_libc.sh
new file mode 100644
index 000000000..6a13f3f24
--- /dev/null
+++ b/litex/soc/software/libc/swap_libc.sh
@@ -0,0 +1,58 @@
+#!/bin/sh
+
+AR=riscv64-unknown-elf-ar
+
+for obj in \
+    vsnprintf.c.o \
+    vfprintf.c.o \
+    fputc.c.o \
+    filestrput.c.o \
+    dtoa_ryu.c.o \
+    ryu_table.c.o \
+    ryu_umul128.c.o \
+    ryu_log10.c.o \
+    ryu_log2pow5.c.o \
+    ryu_pow5bits.c.o \
+    ryu_divpow2.c.o \
+    qsort.c.o \
+    strchr.c.o \
+    strpbrk.c.o \
+    strrchr.c.o \
+    strcpy.c.o \
+    strncpy.c.o \
+    strcmp.S.o \
+    strncmp.c.o \
+    strcat.c.o \
+    strncat.c.o \
+    strlen.c.o \
+    strnlen.c.o \
+    strspn.c.o \
+    memcmp.c.o \
+    memset.S.o \
+    memcpy.c.o \
+    memmove.S.o \
+    strstr.c.o \
+    memchr.c.o \
+    strtoul.c.o \
+    strtol.c.o \
+    snprintf.c.o \
+    sprintf.c.o \
+    rand.c.o \
+    srand.c.o \
+    abort.c.o \
+    errno.c.o \
+    strerror.c.o \
+    strtod.c.o \
+    ctype_.c.o \
+    locale.c.o \
+    mbtowc_r.c.o \
+    wctomb_r.c.o \
+    strcasecmp.c.o \
+    isdigit.c.o \
+; do
+    $AR x "newlib/libc.a" $obj
+    $AR csr "../libbase/libbase.a" $obj
+    $AR csr "../libbase/libbase-nofloat.a" $obj
+    rm $obj
+done
+