style(eeprom): move eeprom code to it's own file

This commit is contained in:
Rekai Nyangadzayi Musuka 2022-10-10 11:33:51 -03:00
parent 13f6ee8ec4
commit cb0eb67e4b
2 changed files with 272 additions and 265 deletions

View File

@ -2,6 +2,8 @@ const std = @import("std");
const Allocator = std.mem.Allocator;
const log = std.log.scoped(.Backup);
const Eeprom = @import("backup/eeprom.zig").Eeprom;
const escape = @import("../../util.zig").escape;
const span = @import("../../util.zig").span;
@ -55,7 +57,7 @@ pub const Backup = struct {
.title = title,
.save_path = path,
.flash = Flash.init(),
.eeprom = Eeprom.init(allocator),
.eeprom = Eeprom.create(allocator),
};
if (backup.save_path) |p| backup.loadSaveFromDisk(allocator, p) catch |e| log.err("Failed to load save: {}", .{e});
@ -300,267 +302,3 @@ const Flash = struct {
return if (self.bank == 1) 0x10000 else @as(usize, 0);
}
};
const Eeprom = struct {
const Self = @This();
addr: u14,
kind: Kind,
state: State,
writer: Writer,
reader: Reader,
allocator: Allocator,
const Kind = enum {
Unknown,
Small, // 512B
Large, // 8KB
};
const State = enum {
Ready,
Read,
Write,
WriteTransfer,
RequestEnd,
};
fn init(allocator: Allocator) Self {
return .{
.kind = .Unknown,
.state = .Ready,
.writer = Writer.init(),
.reader = Reader.init(),
.addr = 0,
.allocator = allocator,
};
}
pub fn read(self: *Self) u1 {
return self.reader.read();
}
pub fn dbgRead(self: *const Self) u1 {
return self.reader.dbgRead();
}
pub fn write(self: *Self, word_count: u16, buf: *[]u8, bit: u1) void {
if (self.guessKind(word_count)) |found| {
log.info("EEPROM Kind: {}", .{found});
self.kind = found;
// buf.len will not equal zero when a save file was found and loaded.
// Right now, we assume that the save file is of the correct size which
// isn't necessarily true, since we can't trust anything a user can influence
// TODO: use ?[]u8 instead of a 0-sized slice?
if (buf.len == 0) {
const len: usize = switch (found) {
.Small => 0x200,
.Large => 0x2000,
else => unreachable,
};
buf.* = self.allocator.alloc(u8, len) catch |e| {
log.err("Failed to resize EEPROM buf to {} bytes", .{len});
std.debug.panic("EEPROM entered irrecoverable state {}", .{e});
};
std.mem.set(u8, buf.*, 0xFF);
}
}
if (self.state == .RequestEnd) {
if (bit != 0) log.debug("EEPROM Request did not end in 0u1. TODO: is this ok?", .{});
self.state = .Ready;
return;
}
switch (self.state) {
.Ready => self.writer.requestWrite(bit),
.Read, .Write => self.writer.addressWrite(self.kind, bit),
.WriteTransfer => self.writer.dataWrite(bit),
.RequestEnd => unreachable, // We return early just above this block
}
self.tick(buf.*);
}
fn guessKind(self: *const Self, word_count: u16) ?Kind {
if (self.kind != .Unknown or self.state != .Read) return null;
return switch (word_count) {
17 => .Large,
9 => .Small,
else => blk: {
log.err("Unexpected length of DMA3 Transfer upon initial EEPROM read: {}", .{word_count});
break :blk null;
},
};
}
fn tick(self: *Self, buf: []u8) void {
switch (self.state) {
.Ready => {
if (self.writer.len() == 2) {
const req = @intCast(u2, self.writer.finish());
switch (req) {
0b11 => self.state = .Read,
0b10 => self.state = .Write,
else => log.err("Unknown EEPROM Request 0b{b:0>2}", .{req}),
}
}
},
.Read => {
switch (self.kind) {
.Large => {
if (self.writer.len() == 14) {
const addr = @intCast(u10, self.writer.finish());
const value = std.mem.readIntSliceLittle(u64, buf[@as(u13, addr) * 8 ..][0..8]);
self.reader.configure(value);
self.state = .RequestEnd;
}
},
.Small => {
if (self.writer.len() == 6) {
// FIXME: Duplicated code from above
const addr = @intCast(u6, self.writer.finish());
const value = std.mem.readIntSliceLittle(u64, buf[@as(u13, addr) * 8 ..][0..8]);
self.reader.configure(value);
self.state = .RequestEnd;
}
},
else => log.err("Unable to calculate EEPROM read address. EEPROM size UNKNOWN", .{}),
}
},
.Write => {
switch (self.kind) {
.Large => {
if (self.writer.len() == 14) {
self.addr = @intCast(u10, self.writer.finish());
self.state = .WriteTransfer;
}
},
.Small => {
if (self.writer.len() == 6) {
self.addr = @intCast(u6, self.writer.finish());
self.state = .WriteTransfer;
}
},
else => log.err("Unable to calculate EEPROM write address. EEPROM size UNKNOWN", .{}),
}
},
.WriteTransfer => {
if (self.writer.len() == 64) {
std.mem.writeIntSliceLittle(u64, buf[self.addr * 8 ..][0..8], self.writer.finish());
self.state = .RequestEnd;
}
},
.RequestEnd => unreachable, // We return early in write() if state is .RequestEnd
}
}
const Reader = struct {
const This = @This();
data: u64,
i: u8,
enabled: bool,
fn init() This {
return .{
.data = 0,
.i = 0,
.enabled = false,
};
}
fn configure(self: *This, value: u64) void {
self.data = value;
self.i = 0;
self.enabled = true;
}
fn read(self: *This) u1 {
if (!self.enabled) return 1;
const bit = if (self.i < 4) blk: {
break :blk 0;
} else blk: {
const idx = @intCast(u6, 63 - (self.i - 4));
break :blk @truncate(u1, self.data >> idx);
};
self.i = (self.i + 1) % (64 + 4);
if (self.i == 0) self.enabled = false;
return bit;
}
fn dbgRead(self: *const This) u1 {
if (!self.enabled) return 1;
const bit = if (self.i < 4) blk: {
break :blk 0;
} else blk: {
const idx = @intCast(u6, 63 - (self.i - 4));
break :blk @truncate(u1, self.data >> idx);
};
return bit;
}
};
const Writer = struct {
const This = @This();
data: u64,
i: u8,
fn init() This {
return .{ .data = 0, .i = 0 };
}
fn requestWrite(self: *This, bit: u1) void {
const idx = @intCast(u1, 1 - self.i);
self.data = (self.data & ~(@as(u64, 1) << idx)) | (@as(u64, bit) << idx);
self.i += 1;
}
fn addressWrite(self: *This, kind: Eeprom.Kind, bit: u1) void {
if (kind == .Unknown) return;
const size: u4 = switch (kind) {
.Large => 13,
.Small => 5,
.Unknown => unreachable,
};
const idx = @intCast(u4, size - self.i);
self.data = (self.data & ~(@as(u64, 1) << idx)) | (@as(u64, bit) << idx);
self.i += 1;
}
fn dataWrite(self: *This, bit: u1) void {
const idx = @intCast(u6, 63 - self.i);
self.data = (self.data & ~(@as(u64, 1) << idx)) | (@as(u64, bit) << idx);
self.i += 1;
}
fn len(self: *const This) u8 {
return self.i;
}
fn finish(self: *This) u64 {
defer self.reset();
return self.data;
}
fn reset(self: *This) void {
self.i = 0;
self.data = 0;
}
};
};

View File

@ -0,0 +1,269 @@
const std = @import("std");
const Allocator = std.mem.Allocator;
const log = std.log.scoped(.Eeprom);
pub const Eeprom = struct {
const Self = @This();
addr: u14,
kind: Kind,
state: State,
writer: Writer,
reader: Reader,
allocator: Allocator,
const Kind = enum {
Unknown,
Small, // 512B
Large, // 8KB
};
const State = enum {
Ready,
Read,
Write,
WriteTransfer,
RequestEnd,
};
pub fn read(self: *Self) u1 {
return self.reader.read();
}
pub fn dbgRead(self: *const Self) u1 {
return self.reader.dbgRead();
}
pub fn write(self: *Self, word_count: u16, buf: *[]u8, bit: u1) void {
if (self.guessKind(word_count)) |found| {
log.info("EEPROM Kind: {}", .{found});
self.kind = found;
// buf.len will not equal zero when a save file was found and loaded.
// Right now, we assume that the save file is of the correct size which
// isn't necessarily true, since we can't trust anything a user can influence
// TODO: use ?[]u8 instead of a 0-sized slice?
if (buf.len == 0) {
const len: usize = switch (found) {
.Small => 0x200,
.Large => 0x2000,
else => unreachable,
};
buf.* = self.allocator.alloc(u8, len) catch |e| {
log.err("Failed to resize EEPROM buf to {} bytes", .{len});
std.debug.panic("EEPROM entered irrecoverable state {}", .{e});
};
std.mem.set(u8, buf.*, 0xFF);
}
}
if (self.state == .RequestEnd) {
if (bit != 0) log.debug("EEPROM Request did not end in 0u1. TODO: is this ok?", .{});
self.state = .Ready;
return;
}
switch (self.state) {
.Ready => self.writer.requestWrite(bit),
.Read, .Write => self.writer.addressWrite(self.kind, bit),
.WriteTransfer => self.writer.dataWrite(bit),
.RequestEnd => unreachable, // We return early just above this block
}
self.tick(buf.*);
}
pub fn create(allocator: Allocator) Self {
return .{
.kind = .Unknown,
.state = .Ready,
.writer = Writer.create(),
.reader = Reader.create(),
.addr = 0,
.allocator = allocator,
};
}
fn guessKind(self: *const Self, word_count: u16) ?Kind {
if (self.kind != .Unknown or self.state != .Read) return null;
return switch (word_count) {
17 => .Large,
9 => .Small,
else => blk: {
log.err("Unexpected length of DMA3 Transfer upon initial EEPROM read: {}", .{word_count});
break :blk null;
},
};
}
fn tick(self: *Self, buf: []u8) void {
switch (self.state) {
.Ready => {
if (self.writer.len() == 2) {
const req = @intCast(u2, self.writer.finish());
switch (req) {
0b11 => self.state = .Read,
0b10 => self.state = .Write,
else => log.err("Unknown EEPROM Request 0b{b:0>2}", .{req}),
}
}
},
.Read => {
switch (self.kind) {
.Large => {
if (self.writer.len() == 14) {
const addr = @intCast(u10, self.writer.finish());
const value = std.mem.readIntSliceLittle(u64, buf[@as(u13, addr) * 8 ..][0..8]);
self.reader.configure(value);
self.state = .RequestEnd;
}
},
.Small => {
if (self.writer.len() == 6) {
// FIXME: Duplicated code from above
const addr = @intCast(u6, self.writer.finish());
const value = std.mem.readIntSliceLittle(u64, buf[@as(u13, addr) * 8 ..][0..8]);
self.reader.configure(value);
self.state = .RequestEnd;
}
},
else => log.err("Unable to calculate EEPROM read address. EEPROM size UNKNOWN", .{}),
}
},
.Write => {
switch (self.kind) {
.Large => {
if (self.writer.len() == 14) {
self.addr = @intCast(u10, self.writer.finish());
self.state = .WriteTransfer;
}
},
.Small => {
if (self.writer.len() == 6) {
self.addr = @intCast(u6, self.writer.finish());
self.state = .WriteTransfer;
}
},
else => log.err("Unable to calculate EEPROM write address. EEPROM size UNKNOWN", .{}),
}
},
.WriteTransfer => {
if (self.writer.len() == 64) {
std.mem.writeIntSliceLittle(u64, buf[self.addr * 8 ..][0..8], self.writer.finish());
self.state = .RequestEnd;
}
},
.RequestEnd => unreachable, // We return early in write() if state is .RequestEnd
}
}
};
const Reader = struct {
const Self = @This();
data: u64,
i: u8,
enabled: bool,
fn create() Self {
return .{
.data = 0,
.i = 0,
.enabled = false,
};
}
fn read(self: *Self) u1 {
if (!self.enabled) return 1;
const bit = if (self.i < 4) blk: {
break :blk 0;
} else blk: {
const idx = @intCast(u6, 63 - (self.i - 4));
break :blk @truncate(u1, self.data >> idx);
};
self.i = (self.i + 1) % (64 + 4);
if (self.i == 0) self.enabled = false;
return bit;
}
fn dbgRead(self: *const Self) u1 {
if (!self.enabled) return 1;
const bit = if (self.i < 4) blk: {
break :blk 0;
} else blk: {
const idx = @intCast(u6, 63 - (self.i - 4));
break :blk @truncate(u1, self.data >> idx);
};
return bit;
}
fn configure(self: *Self, value: u64) void {
self.data = value;
self.i = 0;
self.enabled = true;
}
};
const Writer = struct {
const Self = @This();
data: u64,
i: u8,
fn create() Self {
return .{ .data = 0, .i = 0 };
}
fn requestWrite(self: *Self, bit: u1) void {
const idx = @intCast(u1, 1 - self.i);
self.data = (self.data & ~(@as(u64, 1) << idx)) | (@as(u64, bit) << idx);
self.i += 1;
}
fn addressWrite(self: *Self, kind: Eeprom.Kind, bit: u1) void {
if (kind == .Unknown) return;
const size: u4 = switch (kind) {
.Large => 13,
.Small => 5,
.Unknown => unreachable,
};
const idx = @intCast(u4, size - self.i);
self.data = (self.data & ~(@as(u64, 1) << idx)) | (@as(u64, bit) << idx);
self.i += 1;
}
fn dataWrite(self: *Self, bit: u1) void {
const idx = @intCast(u6, 63 - self.i);
self.data = (self.data & ~(@as(u64, 1) << idx)) | (@as(u64, bit) << idx);
self.i += 1;
}
fn len(self: *const Self) u8 {
return self.i;
}
fn finish(self: *Self) u64 {
defer self.reset();
return self.data;
}
fn reset(self: *Self) void {
self.i = 0;
self.data = 0;
}
};