Files save on baremetal RPI (#137)

Implement FAT32 save mechanism with caching and optimizations to improve performance

Still does not support folders/directories

Cargo.toml

@@ -13,4 +13,7 @@ members = [
 version = "4.0.0"
 authors = ["alloncm <alloncm@gmail.com>"]
 rust-version = "1.73"   # cause of cargo-ndk used to build for android platform
-edition = "2021"
+edition = "2021"
+
+[profile.release]
+lto = true  # Samller binaries and faster code

README.md

@@ -97,13 +97,14 @@ Choose a game with the Joypad bindings (Dpad and A to confirm)
 ### Raspberry Pi Baremetal
 
 Currently only Raspberry Pi 4 is supported using the following instructions:
-* Format a sd card and make a single `FAT32` partition called `boot`
-* Copy the file `config.txt` to the root dir of the sd card
-* Copy the following files from the [Raspberry Pi firmware repo](https://github.com/raspberrypi/firmware/tree/master/boot) onto the SD card:
-    - [fixup4.dat](https://github.com/raspberrypi/firmware/raw/master/boot/fixup4.dat)
-    - [start4.elf](https://github.com/raspberrypi/firmware/raw/master/boot/start4.elf)
-    - [bcm2711-rpi-4-b.dtb](https://github.com/raspberrypi/firmware/raw/master/boot/bcm2711-rpi-4-b.dtb)
-* Copy `kernel7.img` onto the SD card
+* Format a sd card to MBR (not GPT) and create a single `FAT32` partition (On windows you can use Rufus)
+* Copy the following files from the [Raspberry Pi firmware repo](https://github.com/raspberrypi/firmware/tree/191360eaf2e5933eaa0ed76ac0d62722b6f9a58f/boot) onto the SD card:
+    - [fixup4.dat](https://github.com/raspberrypi/firmware/raw/191360eaf2e5933eaa0ed76ac0d62722b6f9a58f/boot/fixup4.dat)
+    - [start4.elf](https://github.com/raspberrypi/firmware/raw/191360eaf2e5933eaa0ed76ac0d62722b6f9a58f/boot/start4.elf)
+    - [bcm2711-rpi-4-b.dtb](https://github.com/raspberrypi/firmware/raw/191360eaf2e5933eaa0ed76ac0d62722b6f9a58f/boot/bcm2711-rpi-4-b.dtb)
+
+    _**Notice**: This is a specific revision, for some reason it broke on the latest version of those files_
+* Copy `kernel7.img` and `config.txt` to the SD card
 * Connect all the peripherals (ili9341 display and gpio buttons)
 * Insert the SD card to the RPI4 and boot it
 

core/src/mmu/carts/mod.rs

@@ -19,11 +19,11 @@ pub const MBC_RAM_SIZE_LOCATION:usize = 0x149;
 pub fn get_ram_size(ram_size_register:u8)->usize{
     match ram_size_register{
         0x0=>0,
-        0x1=>0x800,
+        0x1=>0x800,     // Unofficial - Undefined according to official docs
         0x2=>0x4000,
         0x3=>0x8000,
-        0x4=>0x20000,
-        0x5=>0x10000,
+        0x4=>0x2_0000,
+        0x5=>0x1_0000,
         _=>core::panic!("invalid ram size register {:#X}", ram_size_register)
     }
 }
@@ -34,7 +34,7 @@ pub fn init_ram(ram_reg:u8, external_ram:Option<&'static mut[u8]>)->&'static mut
     match external_ram{
         Some(ram)=>{
             if ram.len() != ram_size{
-                core::panic!("external rom is not in the correct size for the cartridge");
+                core::panic!("External ram is not in the correct size for the cartridge, the save seems corrupted, either fix or delete it and try again");
             }
 
             return ram;

core/src/mmu/gb_mmu.rs

@@ -41,7 +41,7 @@ impl<'a, D:AudioDevice, G:GfxDevice, J:JoypadProvider> Memory for GbMmu<'a, D, G
                     return self.io_bus.ppu.vram.read_current_bank(address-0x8000);
                 }
                 else{
-                    log::warn!("bad vram read");
+                    log::trace!("bad vram read");
                     return BAD_READ_VALUE;
                 }
             },
@@ -50,7 +50,7 @@ impl<'a, D:AudioDevice, G:GfxDevice, J:JoypadProvider> Memory for GbMmu<'a, D, G
                     return self.io_bus.ppu.oam[(address-0xFE00) as usize];
                 }
                 else{
-                    log::warn!("bad oam read");
+                    log::trace!("bad oam read");
                     return BAD_READ_VALUE;
                 }
             }
@@ -80,15 +80,15 @@ impl<'a, D:AudioDevice, G:GfxDevice, J:JoypadProvider> Memory for GbMmu<'a, D, G
                         self.io_bus.ppu.vram.write_current_bank(address-0x8000, value);
                     }
                     else{
-                        log::warn!("bad vram write: address - {:#X}, value - {:#X}, bank - {}", address, value, self.io_bus.ppu.vram.get_bank_reg());
+                        log::trace!("bad vram write: address - {:#X}, value - {:#X}, bank - {}", address, value, self.io_bus.ppu.vram.get_bank_reg());
                     }
                 },
                 0xFE00..=0xFE9F=>{
                     if self.is_oam_ready_for_io(){
                         self.io_bus.ppu.oam[(address-0xFE00) as usize] = value;
                     }
                     else{
-                        log::warn!("bad oam write")
+                        log::trace!("bad oam write")
                     }
                 },
                 _=>self.write_unprotected(address, value)
@@ -249,12 +249,12 @@ impl<'a, D:AudioDevice, G:GfxDevice, J:JoypadProvider> GbMmu<'a, D, G, J>{
     }
 
     fn bad_dma_read(address:u16)->u8{
-        log::warn!("bad memory read during dma. {:#X}", address);
+        log::trace!("bad memory read during dma. {:#X}", address);
         return BAD_READ_VALUE;
     }
 
     fn bad_dma_write(address:u16){
-        log::warn!("bad memory write during dma. {:#X}", address)
+        log::trace!("bad memory write during dma. {:#X}", address)
     }
 
     fn write_color_ram(&mut self, address:u16, color: Color){

core/src/ppu/gb_ppu.rs

@@ -616,7 +616,7 @@ impl<GFX:GfxDevice> GbPpu<GFX>{
             color_ram[(*pallete_index_register & 0b11_1111) as usize] = value;
         }
         else{
-            log::warn!("bad color ram write: index - {:#X}, value: - {:#X}", pallete_index_register, value);
+            log::trace!("bad color ram write: index - {:#X}, value: - {:#X}", pallete_index_register, value);
         }
 
         // if bit 7 is set inderement the dest adderess after write

rpi/Cargo.toml

@@ -11,7 +11,7 @@ magenboy_core = {path = "../core"}
 magenboy_common = {path = "../common"}
 log = "0.4"
 cfg-if = "1"
-bitfield-struct = "0.5"
+bitfield-struct = {version = "0.9", optional = true}
 libc = {version = "0.2", optional = true}
 nix = {version = "0.24", optional = true}
 crossbeam-channel = {version = "0.5", optional = true}
@@ -20,7 +20,7 @@ arrayvec = {version = "0.7.6", default-features = false, optional = true}
 
 [features]
 os = ["magenboy_common/std", "libc", "nix/ioctl", "crossbeam-channel", "rppal"]
-bm = ["arrayvec"]
+bm = ["arrayvec", "bitfield-struct"]
 
 [[bin]]
 name = "rpios"

rpi/build.rs

@@ -44,11 +44,5 @@ fn main(){
         let rpi_version = std::env::var(config::RPI_ENV_VAR_NAME)
             .expect(std::format!("{} env must be set", config::RPI_ENV_VAR_NAME).as_str());
         println!("cargo:rustc-cfg=rpi=\"{}\"", rpi_version);
-
-        // Silent warnings for this cfg     
-        println!("cargo:rustc-check-cfg=cfg(rpi, values(\"4\", \"2\"))");
     }
-
-    // Silent warnings for this cfg 
-    println!("cargo:rustc-check-cfg=cfg(rpi)");
 }

rpi/src/bin/baremetal/link.ld

@@ -1,7 +1,7 @@
 /* Place _start procedure at the entry address for RPI */
 __rpi_32_phys_binary_load_addr = 0x8000;
 __isr_table_addr = 0;
-__stack_size = 0x100000; /* 1MB stack */
+__stack_size = 0x300000; /* 3MB stack */
 ENTRY(__rpi_32_phys_binary_load_addr)   /* enry point */
 
 SECTIONS

rpi/src/bin/baremetal/main.rs

@@ -9,14 +9,24 @@ use core::panic::PanicInfo;
 use arrayvec::ArrayString;
 
 use magenboy_common::{joypad_menu::{joypad_gfx_menu::{self, GfxDeviceMenuRenderer}, JoypadMenu, }, menu::*, VERSION};
-use magenboy_core::machine::{gameboy::GameBoy, mbc_initializer::initialize_mbc};
-use magenboy_rpi::{drivers::*, peripherals::{PERIPHERALS, GpioPull}, configuration::{display::*, joypad::button_to_bcm_pin, emulation::*}, MENU_PIN_BCM, delay};
+use magenboy_core::{machine::{gameboy::GameBoy, mbc_initializer::initialize_mbc}, mmu::carts::Mbc};
+use magenboy_rpi::{drivers::*, peripherals::{PERIPHERALS, GpioPull, ResetMode, Power}, configuration::{display::*, joypad::button_to_bcm_pin, emulation::*}, MENU_PIN_BCM, delay};
+
+#[panic_handler]
+fn panic(info:&PanicInfo)->!{
+    log::error!("An error has occurred!: \r\n{}", info);
+
+    // SAFETY: Defined in boot asm code, no params passed and this function does not returned so no calling convention is even needed
+    unsafe{boot::hang_led()};
+}
 
 const MAX_ROM_SIZE:usize = 0x80_0000;       // 8 MiB, Max size of MBC5 rom
+const MAX_RAM_SIZE:usize = 0x2_0000;        // 128 KiB
 
 // Allocating as static buffer (on the .bss) because it is a very large buffer and 
-// I dont want to cause problems in stack making it overflow and shit (I can increase it when needed but I afraid Id forget)
+// I don't want to cause problems in stack making it overflow and shit (I can increase it when needed but I afraid Id forget)
 static mut ROM_BUFFER:[u8; MAX_ROM_SIZE] = [0;MAX_ROM_SIZE];
+static mut RAM_BUFFER:[u8; MAX_RAM_SIZE] = [0;MAX_RAM_SIZE];
 
 // This function is no regular main.
 // It will not return and will be jumped to from the _start proc in the boot code
@@ -28,14 +38,14 @@ pub extern "C" fn main()->!{
     log::info!("Initialized logger");
     log::info!("running at exec mode: {:#X}", boot::get_cpu_execution_mode());
 
-    let mut power_manager = unsafe{PERIPHERALS.take_power()};
+    let power_manager = unsafe{PERIPHERALS.take_power()};
 
-    let mut fs = Fat32::new();
+    let mut fs = Fat32Fs::new();
     let mut gfx = Ili9341GfxDevice::new(RESET_PIN_BCM, LED_PIN_BCM, TURBO, FRAME_LIMITER);
     let mut pause_menu_gfx = gfx.clone();
     let mut joypad_provider = GpioJoypadProvider::new(button_to_bcm_pin);
     let mut pause_menu_joypad_provider = joypad_provider.clone();
-    log::info!("Initialize all drivers succesfully");
+    log::info!("Initialize all drivers successfully");
 
     let menu_renderer = joypad_gfx_menu::GfxDeviceMenuRenderer::new(&mut gfx);
 
@@ -46,16 +56,18 @@ pub extern "C" fn main()->!{
     let selected_rom = menu.get_menu_selection(&mut joypad_provider);
     log::info!("Selected ROM: {}", selected_rom.get_name());
 
+    // SAFETY: Only ref to this static mut var
     let rom = unsafe{&mut ROM_BUFFER};
     fs.read_file(selected_rom, rom);
-    let mbc = initialize_mbc(&rom[0..selected_rom.size as usize], None);
+    let save_data = try_read_save_file(selected_rom, &mut fs);
+    let mbc = initialize_mbc(&rom[0..selected_rom.size as usize], save_data);
     let mode = mbc.detect_preferred_mode();
 
     let mut gameboy = GameBoy::new_with_mode(mbc, joypad_provider, magenboy_rpi::BlankAudioDevice, gfx, mode);
     log::info!("Initialized gameboy!");
 
     let menu_pin = unsafe {PERIPHERALS.get_gpio().take_pin(MENU_PIN_BCM).into_input(GpioPull::PullUp)};
-    let pause_menu_header:ArrayString<30> = ArrayString::try_from(format_args!("MagenBoy bm v{}", VERSION)).unwrap();
+    let pause_menu_header:ArrayString<30> = ArrayString::try_from(format_args!("MagenBoy v{}", VERSION)).unwrap();
     let pause_menu_renderer = GfxDeviceMenuRenderer::new(&mut pause_menu_gfx);
     let mut pause_menu = JoypadMenu::new(&GAME_MENU_OPTIONS, pause_menu_header.as_str(), pause_menu_renderer);
     loop{
@@ -64,45 +76,80 @@ pub extern "C" fn main()->!{
             match pause_menu.get_menu_selection(&mut pause_menu_joypad_provider){
                 EmulatorMenuOption::Resume => {},
                 EmulatorMenuOption::Restart => {
-                    log::info!("Reseting system");
-                    delay::wait_ms(100);
-                    power_manager.reset(magenboy_rpi::peripherals::ResetMode::Partition0)
+                    log::info!("Resetting system");
+                    reset_system(mbc, fs, power_manager, ResetMode::Partition0, selected_rom);
                 }
                 EmulatorMenuOption::Shutdown => {
                     log::info!("Shuting down system");
-                    delay::wait_ms(100);
-                    power_manager.reset(magenboy_rpi::peripherals::ResetMode::Halt)
+                    reset_system(mbc, fs, power_manager, ResetMode::Halt, selected_rom);
                 }
             }
         }
         gameboy.cycle_frame();
     }
 }
 
-fn read_menu_options(fs: &mut Fat32, menu_options: &mut [MenuOption<FileEntry, ArrayString<{FileEntry::FILENAME_SIZE}>>; 255]) -> usize {
+fn reset_system<'a>(mbc: &'a mut dyn Mbc, mut fs: Fat32Fs, mut power_manager: Power, mode: ResetMode, selected_rom: &FileEntry)->!{
+    let filename = get_save_filename(selected_rom);
+    fs.write_file(filename.as_str(), mbc.get_ram());
+
+    // delaying the reset operation so other low level tasks will have enough time to finish (like uart transmission)
+    delay::wait_ms(100);
+    power_manager.reset(mode);
+}
+
+fn try_read_save_file(selected_rom: &FileEntry, mut fs: &mut Fat32Fs) -> Option<&'static [u8]> {
+    let save_filename = get_save_filename(selected_rom);
+    let file = search_file(&mut fs, save_filename.as_str())?;
+
+    // SAFETY: The only reference to this static mut var
+    let ram = unsafe{&mut RAM_BUFFER[0..file.size as usize]};
+    fs.read_file(&file, ram);
+    log::info!("Found save file for selected rom: {}", file.get_name());
+    return Some(ram);
+}
+
+fn get_save_filename(selected_rom: &FileEntry) -> ArrayString<11> {
+    ArrayString::try_from(format_args!("{}SAV",&selected_rom.get_name()[..8])).unwrap()
+}
+
+fn read_menu_options(fs: &mut Fat32Fs, menu_options: &mut [MenuOption<FileEntry, ArrayString<{FileEntry::FILENAME_SIZE}>>; 255]) -> usize {
+    const FILES_PER_LIST:usize = 20;
+
     let mut menu_options_size = 0;
     let mut root_dir_offset = 0;
-    const FILES_PER_LIST:usize = 20;
-    'search_dir_loop: loop{
+    loop{
         let dir_entries = fs.root_dir_list::<FILES_PER_LIST>(root_dir_offset);
-        for entry in dir_entries{
-            let Some(entry) = entry else {break 'search_dir_loop};
+        for entry in &dir_entries{
             let extension = entry.get_extension();
             if extension.eq_ignore_ascii_case("gb") || extension.eq_ignore_ascii_case("gbc"){
                 menu_options[menu_options_size] = MenuOption{ value: entry.clone(), prompt: ArrayString::from(entry.get_name()).unwrap() };
                 menu_options_size += 1;
                 log::debug!("Detected ROM: {}", entry.get_name());
             }
         }
+        // The fact that its not completely full indicates that there are no more unread entries left
+        if dir_entries.remaining_capacity() != 0{
+            break;
+        }
         root_dir_offset += FILES_PER_LIST;
     }
     return menu_options_size;
 }
 
-#[panic_handler]
-fn panic(info:&PanicInfo)->!{
-    log::error!("An error has occoured!");
-    log::error!("{}", info);
-
-    unsafe{boot::hang_led()};
+fn search_file(fs:&mut Fat32Fs, filename: &str)->Option<FileEntry>{
+    let mut root_dir_offset = 0;
+    const FILES_PER_LIST:usize = 20;
+    loop{
+        let dir_entries = fs.root_dir_list::<FILES_PER_LIST>(root_dir_offset);
+        for entry in &dir_entries{
+            if entry.get_name() == filename{
+                return Some(entry.clone());
+            }
+        }
+        if dir_entries.remaining_capacity() != 0{
+            return None;
+        }
+        root_dir_offset += FILES_PER_LIST;
+    }
 }