From 6920f5d5640e0facb662b98d333b46d67026926a Mon Sep 17 00:00:00 2001
From: Saurabh Singh <saurabh.s99100@gmail.com>
Date: Fri, 20 Oct 2023 00:09:11 -0400
Subject: [PATCH] sim, bootloader: setup & Handle bootmode properly

- in hsoc target:sim option reduces led blink delay
- sim: add bootmode cli option in hsoc backend
---
 Makefile                    |  2 +-
 sim/backend_hydrogensoc.cpp |  5 +++++
 sim/backend_hydrogensoc.hpp |  1 +
 sim/main.cpp                |  4 ++++
 sw/bootloader/Makefile      |  7 +++++++
 sw/bootloader/hydrogensoc.h | 20 ++++++++++++++++----
 6 files changed, 34 insertions(+), 5 deletions(-)

diff --git a/Makefile b/Makefile
index 3dbef9f6..6a8e976f 100644
--- a/Makefile
+++ b/Makefile
@@ -100,7 +100,7 @@ test: sim lib						## Test the build using banner example
 .PHONY : boot
 boot: lib                     		## Build bootloader for given target [default: atombones]
 	@printf "$(CLR_GR)>> Building bootloader [soctarget:$(soctarget)] $(CLR_NC)\n"
-	make $(MKFLAGS) -C $(bootloader_dir) soctarget=$(soctarget)
+	make $(MKFLAGS) -C $(bootloader_dir) soctarget=$(soctarget) sim=true
 
 
 .PHONY: clean-boot
diff --git a/sim/backend_hydrogensoc.cpp b/sim/backend_hydrogensoc.cpp
index 108b3459..db4265a6 100644
--- a/sim/backend_hydrogensoc.cpp
+++ b/sim/backend_hydrogensoc.cpp
@@ -31,6 +31,8 @@
 
 #define BBUART_FRATIO 3
 
+#define BOOTMODE_PIN_OFFSET 8
+
 Backend_atomsim::Backend_atomsim(Atomsim *sim, Backend_config config) : Backend(sim, &(sim->simstate_)),
                                                                         config_(config),
                                                                         using_vuart_(config.vuart_portname != "")
@@ -161,6 +163,9 @@ int Backend_atomsim::tick()
         return 1;
     }
 
+    // Force the bootmode switch value
+    tb->m_core->gpio_io = (0b11 & config_.bootmode) << BOOTMODE_PIN_OFFSET;
+
     // perform uart transaction (if any)
     UART();
 
diff --git a/sim/backend_hydrogensoc.hpp b/sim/backend_hydrogensoc.hpp
index 7ae64cec..1624722a 100644
--- a/sim/backend_hydrogensoc.hpp
+++ b/sim/backend_hydrogensoc.hpp
@@ -16,6 +16,7 @@ struct Backend_config
     std::string vuart_portname  = "";
     uint32_t vuart_baudrate     = 115200;
     bool enable_uart_dump       = false;
+    int bootmode                = 1;    // Jump to RAM
 };
 
 
diff --git a/sim/main.cpp b/sim/main.cpp
index 7a03192a..621e91fe 100755
--- a/sim/main.cpp
+++ b/sim/main.cpp
@@ -90,6 +90,10 @@ void parse_commandline_args(int argc, char**argv, Atomsim_config &sim_config, Ba
 		("bootrom-image", "Specify bootrom hex image", cxxopts::value<std::string>(backend_config.bootrom_img)->default_value(default_backend_config.bootrom_img))
 		("ram-size", "Specify size of RAM memory to simulate (in KB)", cxxopts::value<uint32_t>(backend_config.ram_size_kb)->default_value(std::to_string(default_backend_config.ram_size_kb)))
 		#endif
+
+		#ifdef TARGET_HYDROGENSOC
+		("bootmode", "Specify bootmode signal", cxxopts::value<int>(backend_config.bootmode)->default_value(std::to_string(default_backend_config.bootmode)))
+		#endif
 		;
 
 		options.add_options("Debug")
diff --git a/sw/bootloader/Makefile b/sw/bootloader/Makefile
index a6737b72..8e0b625b 100644
--- a/sw/bootloader/Makefile
+++ b/sw/bootloader/Makefile
@@ -1,5 +1,7 @@
 EXEC:= bootloader
 
+sim ?= false
+
 RVPREFIX:= riscv64-unknown-elf
 
 CFLAGS:= -mabi=ilp32 -march=rv32i -nostartfiles -ffreestanding -Os
@@ -9,6 +11,11 @@ LFLAGS:= -L $(RVATOM_LIB)/ -T $(RVATOM_LIB)/link/link_bootloader.ld -lcatom -Xli
 
 CONVELF_ARGS:= -t elf -c
 
+ifeq ($(sim), true) 
+    CFLAGS+= -DSIM
+endif
+
+
 ifeq ($(MAKECMDGOALS),clean)
 else
     ifeq ($(soctarget), atombones)
diff --git a/sw/bootloader/hydrogensoc.h b/sw/bootloader/hydrogensoc.h
index 3d4fc712..f90376a0 100644
--- a/sw/bootloader/hydrogensoc.h
+++ b/sw/bootloader/hydrogensoc.h
@@ -42,12 +42,17 @@ extern uint32_t __approm_size;
  */
 void led_blink(int pin, int count, int time_period)
 {
+    int halfperiod = time_period >> 1;
+    #ifdef SIM
+    halfperiod = 0;
+    #endif
+
     for(int i=0; i<count; i++) 
     {
         gpio_write(pin, HIGH);
-        sleep_ms(time_period >> 1);
+        sleep_ms(halfperiod);
         gpio_write(pin, LOW);
-        sleep_ms(time_period >> 1);
+        sleep_ms(halfperiod);
     }
 }
 
@@ -67,8 +72,15 @@ void * platform_init() {
     led_blink(BOOTLED_PIN, START_LED_FLASHES, 50);
 
     // get bootmode
-    uint8_t bootmode = (uint8_t)gpio_read(BOOTMODE_PIN0)
-                        | (((uint8_t)gpio_read(BOOTMODE_PIN1)) << 1);
+    uint8_t pin0_val = (uint8_t)gpio_read(BOOTMODE_PIN0);
+    uint8_t pin1_val = (uint8_t)gpio_read(BOOTMODE_PIN1);
+    uint8_t bootmode = pin0_val | pin1_val << 1;
+
+    // Print Bootmode
+    P(putchar('0'+pin0_val);)
+    P(putchar('0'+pin1_val);)
+    P(putchar(':');)
+
     /**
      * Bootmode: 
      *  0b00: flashboot