From ce957faaa9bbf5785e73ba76eed232968a281547 Mon Sep 17 00:00:00 2001
From: Mateusz Faderewski <sc@mateuszfaderewski.pl>
Date: Fri, 10 Feb 2023 11:45:15 +0100
Subject: [PATCH] [SC64][SW] Added firmware update overwrite safeguard

---
 sw/controller/src/cfg.c |  6 ++++++
 sw/controller/src/cfg.h |  1 +
 sw/controller/src/usb.c | 10 ++++++++--
 3 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/sw/controller/src/cfg.c b/sw/controller/src/cfg.c
index 3225a5e..783ec3b 100644
--- a/sw/controller/src/cfg.c
+++ b/sw/controller/src/cfg.c
@@ -356,6 +356,12 @@ bool cfg_update (uint32_t *args) {
     return false;
 }
 
+bool cfg_set_rom_write_enable (bool value) {
+    uint32_t scr = fpga_reg_get(REG_CFG_SCR);
+    cfg_change_scr_bits(CFG_SCR_ROM_WRITE_ENABLED, value);
+    return (scr & CFG_SCR_ROM_WRITE_ENABLED);
+}
+
 save_type_t cfg_get_save_type (void) {
     return p.save_type;
 }
diff --git a/sw/controller/src/cfg.h b/sw/controller/src/cfg.h
index ffac1c1..4d3b409 100644
--- a/sw/controller/src/cfg.h
+++ b/sw/controller/src/cfg.h
@@ -19,6 +19,7 @@ typedef enum {
 uint32_t cfg_get_version (void);
 bool cfg_query (uint32_t *args);
 bool cfg_update (uint32_t *args);
+bool cfg_set_rom_write_enable (bool value);
 save_type_t cfg_get_save_type (void);
 void cfg_get_time (uint32_t *args);
 void cfg_set_time (uint32_t *args);
diff --git a/sw/controller/src/usb.c b/sw/controller/src/usb.c
index 008ae80..9a1e367 100644
--- a/sw/controller/src/usb.c
+++ b/sw/controller/src/usb.c
@@ -252,15 +252,19 @@ static void usb_rx_process (void) {
                 }
                 break;
 
-            case 'f':
+            case 'f': {
+                bool rom_write_enable_restore = cfg_set_rom_write_enable(false);
                 p.response_info.data[0] = update_backup(p.rx_args[0], &p.response_info.data[1]);
                 p.rx_state = RX_STATE_IDLE;
                 p.response_pending = true;
                 p.response_error = (p.response_info.data[0] != UPDATE_OK);
                 p.response_info.data_length = 8;
+                cfg_set_rom_write_enable(rom_write_enable_restore);
                 break;
+            }
 
-            case 'F':
+            case 'F': {
+                bool rom_write_enable_restore = cfg_set_rom_write_enable(false);
                 p.response_info.data[0] = update_prepare(p.rx_args[0], p.rx_args[1]);
                 p.rx_state = RX_STATE_IDLE;
                 p.response_pending = true;
@@ -269,8 +273,10 @@ static void usb_rx_process (void) {
                     p.response_info.done_callback = update_start;
                 } else {
                     p.response_error = true;
+                    cfg_set_rom_write_enable(rom_write_enable_restore);
                 }
                 break;
+            }
 
             case 'p':
                 if (p.rx_args[0]) {