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chore: refactor flash impl

This commit is contained in:
Rekai Nyangadzayi Musuka 2022-11-17 08:52:33 -04:00
parent ee1c0bb313
commit 96a9ae2ca5
2 changed files with 67 additions and 69 deletions
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57
src/core/bus/backup.zig
View File

@ -40,61 +40,18 @@ pub const Backup = struct {
None,
};
pub fn read(self: *const Self, address: usize) u8 {
const addr = address & 0xFFFF;
pub fn read(self: *const Self, address: u32) u8 {
switch (self.kind) {
.Flash => {
switch (addr) {
0x0000 => if (self.flash.id_mode) return 0x32, // Panasonic manufacturer ID
0x0001 => if (self.flash.id_mode) return 0x1B, // Panasonic device ID
else => {},
}
return self.flash.read(self.buf, addr);
},
.Flash1M => {
switch (addr) {
0x0000 => if (self.flash.id_mode) return 0x62, // Sanyo manufacturer ID
0x0001 => if (self.flash.id_mode) return 0x13, // Sanyo device ID
else => {},
}
return self.flash.read(self.buf, addr);
},
.Sram => return self.buf[addr & 0x7FFF], // 32K SRAM chip is mirrored
.Flash, .Flash1M => return self.flash.read(self.buf, address),
.Sram => return self.buf[address & 0x7FFF], // 32K SRAM chip is mirrored
.None, .Eeprom => return 0xFF,
}
}
pub fn write(self: *Self, address: usize, byte: u8) void {
const addr = address & 0xFFFF;
pub fn write(self: *Self, address: u32, value: u8) void {
switch (self.kind) {
.Flash, .Flash1M => {
if (self.flash.prep_write) return self.flash.write(self.buf, addr, byte);
if (self.flash.shouldEraseSector(addr, byte)) return self.flash.erase(self.buf, addr);
switch (addr) {
0x0000 => if (self.kind == .Flash1M and self.flash.set_bank) {
self.flash.bank = @truncate(u1, byte);
},
0x5555 => {
if (self.flash.state == .Command) {
self.flash.handleCommand(self.buf, byte);
} else if (byte == 0xAA and self.flash.state == .Ready) {
self.flash.state = .Set;
} else if (byte == 0xF0) {
self.flash.state = .Ready;
}
},
0x2AAA => if (byte == 0x55 and self.flash.state == .Set) {
self.flash.state = .Command;
},
else => {},
}
},
.Sram => self.buf[addr & 0x7FFF] = byte,
.Flash, .Flash1M => self.flash.write(self.buf, address, value),
.Sram => self.buf[address & 0x7FFF] = value,
.None, .Eeprom => {},
}
}
@ -118,7 +75,7 @@ pub const Backup = struct {
.kind = kind,
.title = title,
.save_path = path,
.flash = Flash.create(),
.flash = try Flash.create(if (kind == .Flash1M) .Flash1M else .Flash),
.eeprom = Eeprom.create(allocator),
};

79
src/core/bus/backup/Flash.zig
View File

@ -3,42 +3,83 @@ const std = @import("std");
const Self = @This();
state: State,
kind: Kind,
bank: u1,
id_mode: bool,
set_bank: bool,
prep_erase: bool,
prep_write: bool,
bank: u1,
const Kind = enum { Flash, Flash1M };
const State = enum { Ready, Set, Command };
const State = enum {
Ready,
Set,
Command,
};
pub fn read(self: *const Self, buf: []u8, address: u32) u8 {
const addr = address & 0xFFFF;
pub fn read(self: *const Self, buf: []u8, idx: usize) u8 {
return buf[self.address() + idx];
if (self.kind == .Flash1M) {
switch (addr) {
0x0000 => if (self.id_mode) return 0x32, // Panasonic manufacturer ID
0x0001 => if (self.id_mode) return 0x1B, // Panasonic device ID
else => {},
}
} else {
switch (addr) {
0x0000 => if (self.id_mode) return 0x62, // Sanyo manufacturer ID
0x0001 => if (self.id_mode) return 0x13, // Sanyo device ID
else => {},
}
}
pub fn write(self: *Self, buf: []u8, idx: usize, byte: u8) void {
buf[self.address() + idx] = byte;
return buf[self.baseAddress() + addr];
}
pub fn write(self: *Self, buf: []u8, address: u32, value: u8) void {
const addr = address & 0xFFFF;
if (self.prep_write) return self._write(buf, addr, value);
if (self.shouldEraseSector(addr, value)) return self.erase(buf, addr);
switch (addr) {
0x0000 => if (self.kind == .Flash1M and self.set_bank) {
self.bank = @truncate(u1, value);
},
0x5555 => {
if (self.state == .Command) {
self.handleCommand(buf, value);
} else if (value == 0xAA and self.state == .Ready) {
self.state = .Set;
} else if (value == 0xF0) {
self.state = .Ready;
}
},
0x2AAA => if (value == 0x55 and self.state == .Set) {
self.state = .Command;
},
else => {},
}
}
fn _write(self: *Self, buf: []u8, idx: usize, byte: u8) void {
buf[self.baseAddress() + idx] = byte;
self.prep_write = false;
}
pub fn create() Self {
pub fn create(kind: Kind) !Self {
return .{
.state = .Ready,
.kind = kind,
.bank = 0,
.id_mode = false,
.set_bank = false,
.prep_erase = false,
.prep_write = false,
.bank = 0,
};
}
pub fn handleCommand(self: *Self, buf: []u8, byte: u8) void {
switch (byte) {
fn handleCommand(self: *Self, buf: []u8, value: u8) void {
switch (value) {
0x90 => self.id_mode = true,
0xF0 => self.id_mode = false,
0xB0 => self.set_bank = true,
@ -48,18 +89,18 @@ pub fn handleCommand(self: *Self, buf: []u8, byte: u8) void {
self.prep_erase = false;
},
0xA0 => self.prep_write = true,
else => std.debug.panic("Unhandled Flash Command: 0x{X:0>2}", .{byte}),
else => std.debug.panic("Unhandled Flash Command: 0x{X:0>2}", .{value}),
}
self.state = .Ready;
}
pub fn shouldEraseSector(self: *const Self, addr: usize, byte: u8) bool {
fn shouldEraseSector(self: *const Self, addr: usize, byte: u8) bool {
return self.state == .Command and self.prep_erase and byte == 0x30 and addr & 0xFFF == 0x000;
}
pub fn erase(self: *Self, buf: []u8, sector: usize) void {
const start = self.address() + (sector & 0xF000);
fn erase(self: *Self, buf: []u8, sector: usize) void {
const start = self.baseAddress() + (sector & 0xF000);
std.mem.set(u8, buf[start..][0..0x1000], 0xFF);
self.prep_erase = false;
@ -67,6 +108,6 @@ pub fn erase(self: *Self, buf: []u8, sector: usize) void {
}
/// Base Address
inline fn address(self: *const Self) usize {
inline fn baseAddress(self: *const Self) usize {
return if (self.bank == 1) 0x10000 else @as(usize, 0);
}