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package main
import (
"cmp"
"context"
bin "encoding/binary"
"fmt"
"slices"
"go.einride.tech/can"
"git.samanthony.xyz/can_gauge_interface/sw/cal/canbus"
)
const (
tblCtrlId uint32 = 0x1272000
tblCtrlMask uint32 = 0x1FFFF00
maxTabRows = 32
)
type Table struct {
sigIndex uint8
rows []Row
}
type Row struct {
key int32
val uint16
}
func (t *Table) Insert(key int32, val uint16) error {
if len(t.rows) >= maxTabRows {
return fmt.Errorf("too many rows")
}
i, ok := slices.BinarySearchFunc(t.rows, key, cmpRowKey)
if ok {
return ErrDupKey{key}
}
t.rows = slices.Insert(t.rows, i, Row{key, val})
return nil
}
func cmpRowKey(row Row, key int32) int {
return cmp.Compare(row.key, key)
}
// Transmit a table in Table Control frames so the Interface can store it in its EEPROM.
func (tbl Table) Send(bus canbus.Bus) error {
// Send populated rows
var i int
for i = 0; i < len(tbl.rows); i++ {
if err := sendRow(tbl.sigIndex, uint8(i), tbl.rows[i], bus); err != nil {
return err
}
}
// Fill rest of table with last row
lastRow := tbl.rows[len(tbl.rows)-1]
for ; i < maxTabRows; i++ {
if err := sendRow(tbl.sigIndex, uint8(i), lastRow, bus); err != nil {
return err
}
}
return nil
}
// Transmit a Table Control frame containing one row of a table.
func sendRow(sigIndex, rowIndex uint8, row Row, bus canbus.Bus) error {
frame, err := marshalTblCtrlFrame(sigIndex, rowIndex, row)
if err != nil {
return err
}
var retry int
for retry = 0; retry < maxRetries; retry++ {
// Write to EEPROM
ctx, _ := context.WithTimeout(context.Background(), timeout)
if err := bus.Send(ctx, frame); err != nil {
return err
}
// Read back
request := tblCtrlRequest(sigIndex, rowIndex)
ctx, _ = context.WithTimeout(context.Background(), timeout)
if err := bus.Send(ctx, request); err != nil {
return err
}
ctx, _ = context.WithTimeout(context.Background(), timeout)
reply, err := bus.Receive(ctx)
if err != nil {
return err
}
rRow, rSigIndex, rRowIndex, err := unmarshalTblCtrlFrame(reply)
if err == errWrongId || rSigIndex != sigIndex || rRowIndex != rowIndex {
continue
} else if err != nil {
return err
}
// Verify
if rRow == row {
fmt.Printf("Table %d row %d OK\n", sigIndex, rowIndex)
return nil // success
} else {
weprintf("Warning: table %d row %d verification failed; rewriting...\n", sigIndex, rowIndex)
continue
}
}
// Max retries exceeded
return fmt.Errorf("table %d row %d verification failed", sigIndex, rowIndex)
}
func marshalTblCtrlFrame(sigIndex, rowIndex uint8, row Row) (can.Frame, error) {
var data [8]byte
if _, err := bin.Encode(data[0:4], bin.BigEndian, row.key); err != nil {
return can.Frame{}, err
}
if _, err := bin.Encode(data[4:6], bin.BigEndian, row.val); err != nil {
return can.Frame{}, err
}
return can.Frame{
ID: uint32(tblCtrlId) | uint32((sigIndex<<5)&0xE0) | uint32(rowIndex&0x1F),
Length: 6,
Data: data,
IsExtended: true,
}, nil
}
func unmarshalTblCtrlFrame(frame can.Frame) (row Row, sigIndex, rowIndex uint8, err error) {
if !frame.IsExtended || frame.ID&tblCtrlMask != tblCtrlId {
err = errWrongId
return
}
if frame.Length != 6 {
err = fmt.Errorf("Table Control frame has wrong DLC: %d", frame.Length)
return
}
sigIndex = uint8((frame.ID & 0xE0) >> 5)
rowIndex = uint8(frame.ID & 0x1F)
_, err = bin.Decode(frame.Data[0:4], bin.BigEndian, &row.key)
if err != nil {
return
}
_, err = bin.Decode(frame.Data[4:6], bin.BigEndian, &row.val)
return
}
// Construct a Table Control REMOTE REQUEST frame.
func tblCtrlRequest(sigIndex, rowIndex uint8) can.Frame {
return can.Frame{
ID: tblCtrlId | uint32((sigIndex<<5)&0xE0) | uint32(rowIndex&0x1F),
IsRemote: true,
IsExtended: true,
}
}
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