From 6d0c87f30d35b5303369cb5038d6497529429eda Mon Sep 17 00:00:00 2001
From: Yvan Tortorella <ytortorella@lagrev3.ee.ethz.ch>
Date: Mon, 4 Dec 2023 08:55:22 +0100
Subject: [PATCH] Make it possible to use printf during bare-metal execution.

---
 sw/include/cheshire_io.h | 13 +++++++++++++
 sw/include/dif/uart.h    |  6 +++++-
 sw/include/init.h        |  9 +++++++++
 sw/lib/cheshire_io.c     | 29 +++++++++++++++++++++++++++++
 sw/lib/crt0.S            |  8 +++++++-
 sw/lib/dif/uart.c        | 16 ++++++++++++++--
 sw/lib/init.c            | 18 ++++++++++++++++++
 7 files changed, 95 insertions(+), 4 deletions(-)
 create mode 100644 sw/include/cheshire_io.h
 create mode 100644 sw/include/init.h
 create mode 100644 sw/lib/cheshire_io.c
 create mode 100644 sw/lib/init.c

diff --git a/sw/include/cheshire_io.h b/sw/include/cheshire_io.h
new file mode 100644
index 00000000..53a85eae
--- /dev/null
+++ b/sw/include/cheshire_io.h
@@ -0,0 +1,13 @@
+// Copyright 2022 ETH Zurich and University of Bologna.
+// Licensed under the Apache License, Version 2.0, see LICENSE for details.
+// SPDX-License-Identifier: Apache-2.0
+
+#include "regs/cheshire.h"
+#include "dif/clint.h"
+#include "dif/uart.h"
+#include "util.h"
+#include "params.h"
+
+void cheshire_init_io();
+
+void cheshire_close_io();
diff --git a/sw/include/dif/uart.h b/sw/include/dif/uart.h
index 134ec814..9f4c6e95 100644
--- a/sw/include/dif/uart.h
+++ b/sw/include/dif/uart.h
@@ -42,6 +42,10 @@ uint8_t uart_read(void *uart_base);
 void uart_read_str(void *uart_base, void *dst, uint64_t len);
 
 // Default UART provides console
-void _putchar(char byte);
+void uart_open();
+
+void _putchar(char character);
 
 char _getchar();
+
+void uart_close();
diff --git a/sw/include/init.h b/sw/include/init.h
new file mode 100644
index 00000000..9b471ec5
--- /dev/null
+++ b/sw/include/init.h
@@ -0,0 +1,9 @@
+// Copyright 2022 ETH Zurich and University of Bologna.
+// Licensed under the Apache License, Version 2.0, see LICENSE for details.
+// SPDX-License-Identifier: Apache-2.0
+
+#include "cheshire_io.h"
+
+void soc_init();
+
+void soc_close();
diff --git a/sw/lib/cheshire_io.c b/sw/lib/cheshire_io.c
new file mode 100644
index 00000000..319701b2
--- /dev/null
+++ b/sw/lib/cheshire_io.c
@@ -0,0 +1,29 @@
+// Copyright 2022 ETH Zurich and University of Bologna.
+// Licensed under the Apache License, Version 2.0, see LICENSE for details.
+// SPDX-License-Identifier: Apache-2.0
+//
+// Yvan Tortorella <yvan.tortorella@unibo.it>
+//
+// Library containing IO init/close functions.
+
+#include "cheshire_io.h"
+
+void cheshire_init_io() {
+  // Initialize UART first
+  uart_open();
+  
+  // Initialize other IOs
+  // .
+  // .
+  // .
+};
+
+void cheshire_close_io() {
+  // Close UART first
+  uart_close();
+
+  // Close other IOs
+  // .
+  // .
+  // .
+};
diff --git a/sw/lib/crt0.S b/sw/lib/crt0.S
index ebf372ad..c16dc390 100644
--- a/sw/lib/crt0.S
+++ b/sw/lib/crt0.S
@@ -111,8 +111,12 @@ _fp_init:
     // Set FS state to "Clean"
     csrrc x0, mstatus, t1
 
-    // Full fence, then jump to main
+    // Full fence, then init SoC
     fence
+
+    // Init SoC, than jump to main
+    jal x1, soc_init
+
     call main
 
 // If main returns, we end up here
@@ -127,6 +131,8 @@ _exit:
     ori  t0, t0, 1
     la t1, __base_regs
     sw t0, 8(t1)     // regs.SCRATCH[2]
+    // Flush everything before exiting.
+    jal x1, soc_close
     // Hand over to whatever called us, passing return
     ret
 
diff --git a/sw/lib/dif/uart.c b/sw/lib/dif/uart.c
index 09cef30a..73cbef79 100644
--- a/sw/lib/dif/uart.c
+++ b/sw/lib/dif/uart.c
@@ -5,6 +5,8 @@
 // Nils Wistoff <nwistoff@iis.ee.ethz.ch>
 // Paul Scheffler <paulsc@iis.ee.ethz.ch>
 
+#include "regs/cheshire.h"
+#include "dif/clint.h"
 #include "dif/uart.h"
 #include "util.h"
 #include "params.h"
@@ -64,10 +66,20 @@ void uart_read_str(void *uart_base, void *dst, uint64_t len) {
 }
 
 // Default UART provides console
-void _putchar(char byte) {
-    uart_write(&__base_uart, byte);
+void uart_open(){
+  uint32_t rtc_freq = *reg32(&__base_regs, CHESHIRE_RTC_FREQ_REG_OFFSET);
+  uint64_t reset_freq = clint_get_core_freq(rtc_freq, 2500);
+  uart_init(&__base_uart, reset_freq, 115200);
+};
+
+void _putchar(char character) {
+    uart_write(&__base_uart, character);
 };
 
 char _getchar() {
     return uart_read(&__base_uart);
 };
+
+void uart_close() {
+  uart_write_flush(&__base_uart);
+};
diff --git a/sw/lib/init.c b/sw/lib/init.c
new file mode 100644
index 00000000..07ba1f1b
--- /dev/null
+++ b/sw/lib/init.c
@@ -0,0 +1,18 @@
+// Copyright 2022 ETH Zurich and University of Bologna.
+// Licensed under the Apache License, Version 2.0, see LICENSE for details.
+// SPDX-License-Identifier: Apache-2.0
+//
+// Yvan Tortorella <yvan.tortorella@unibo.it>
+//
+// Library containing general SoC init/close functions.
+
+#include "init.h"
+
+void soc_init() {
+  // IO initialization
+  cheshire_init_io();
+};
+
+void soc_close() {
+  cheshire_close_io();
+};