[newlib-cygwin/main] arc: libgloss: Add support of IoT Development Kit board

[Jeff Johnston <jjohnstn@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=4f50d9d6204987f84b3d1912a543f21ba1378f41

commit 4f50d9d6204987f84b3d1912a543f21ba1378f41
Author: Yuriy Kolerov <kolerov93@gmail.com>
Date:   Tue May 21 10:56:54 2024 +0100

    arc: libgloss: Add support of IoT Development Kit board
    
    An example of building an application:
    
        $ arc-elf32-gcc -mcpu=em -specs=iotdk.specs main.c -o main
    
    Signed-off-by: Vladimir Isaev <vvisaev@gmail.com>
    Signed-off-by: Yuriy Kolerov <kolerov93@gmail.com>

Diff:
---
 libgloss/arc/iotdk-uart-setup.c | 36 ++++++++++++++++++++++++++++++++++++
 libgloss/arc/iotdk.ld           | 14 ++++++++++++++
 libgloss/arc/iotdk.specs        | 18 ++++++++++++++++++
 3 files changed, 68 insertions(+)

diff --git a/libgloss/arc/iotdk-uart-setup.c b/libgloss/arc/iotdk-uart-setup.c
new file mode 100644
index 000000000..e6d2ac887
--- /dev/null
+++ b/libgloss/arc/iotdk-uart-setup.c
@@ -0,0 +1,36 @@
+/*
+ * iotdk-setup.c -- provide _setup_low_level() to initialize UART.
+ *
+ * Copyright (c) 2024 Synopsys Inc.
+ *
+ * The authors hereby grant permission to use, copy, modify, distribute,
+ * and license this software and its documentation for any purpose, provided
+ * that existing copyright notices are retained in all copies and that this
+ * notice is included verbatim in any distributions. No written agreement,
+ * license, or royalty fee is required for any of the authorized uses.
+ * Modifications to this software may be copyrighted by their authors
+ * and need not follow the licensing terms described here, provided that
+ * the new terms are clearly indicated on the first page of each file where
+ * they apply.
+ *
+ */
+
+#include "uart-8250.h"
+
+/* Setup UART parameters.  */
+int
+_setup_low_level (void)
+{
+  void * const uart_base = (void *) 0x80014000;
+  const uint32_t uart_clk_ena = 0xC0;
+  const int uart_aux_mapped = 1;
+  const uint32_t uart_clock = 16000000;
+  const uint32_t uart_baud = 115200;
+
+  /* For this platform we have to enable UART clock before configuring it.   */
+  __builtin_arc_sr (0x01, (uint32_t) uart_base + uart_clk_ena);
+
+  _uart_8250_setup (uart_base, uart_aux_mapped, uart_clock, uart_baud);
+
+  return 0;
+}
diff --git a/libgloss/arc/iotdk.ld b/libgloss/arc/iotdk.ld
new file mode 100644
index 000000000..18874e819
--- /dev/null
+++ b/libgloss/arc/iotdk.ld
@@ -0,0 +1,14 @@
+/* Memory map for ARC IoT DK - EM9D */
+
+MEMORY
+{
+    ICCM : ORIGIN = 0x20000000, LENGTH = 256K
+    DCCM : ORIGIN = 0x80000000, LENGTH = 128K
+}
+
+REGION_ALIAS("startup", ICCM)
+REGION_ALIAS("text", ICCM)
+REGION_ALIAS("data", DCCM)
+REGION_ALIAS("sdata", DCCM)
+
+INCLUDE arcv2elf-common.ld
diff --git a/libgloss/arc/iotdk.specs b/libgloss/arc/iotdk.specs
new file mode 100644
index 000000000..9f9ba433f
--- /dev/null
+++ b/libgloss/arc/iotdk.specs
@@ -0,0 +1,18 @@
+%rename link iotdk_link
+%rename link_gcc_c_sequence iotdk_link_gcc_c_sequence
+%rename startfile iotdk_startfile
+
+*link:
+%(iotdk_link) -T iotdk.ld%s
+
+*iotdk_libgloss:
+-luart_8250 -liotdk_uart
+
+*iotdk_libc:
+%{!specs=nano.specs:-lc} %{specs=nano.specs:-lc_nano}
+
+*link_gcc_c_sequence:
+%(iotdk_link_gcc_c_sequence) --start-group %G %(iotdk_libc) %(iotdk_libgloss) --end-group
+
+*startfile:
+%(iotdk_startfile) arc-main-helper%O%s