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/
fpga.go
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/
fpga.go
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// Copyright 2019 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// FPGA interface.
package gocw
import (
"fmt"
"io"
"net/http"
"time"
"github.com/google/gocw/hardware"
"github.com/golang/glog"
)
type Fpga struct {
dev UsbDeviceInterface
Mem *Memory
}
func (f *Fpga) IsProgrammed() (bool, error) {
glog.V(2).Info("FPGA is programmed")
var err error
var status uint32
if err = f.dev.ControlIn(ReqFpgaStatus, 0, &status); err != nil {
return false, fmt.Errorf("ReqFpgaStatus: %v", err)
}
return bool(status&1 == 1), nil
}
func (f *Fpga) ctrlProgram(val uint16) error {
return f.dev.ControlOut(ReqFpgaProgram, val, []byte{})
}
func (f *Fpga) Program(bitstream io.Reader) error {
var err error
glog.V(1).Info("Programming FPGA")
// Erase the FPGA by toggling PROGRAM pin, setup
// NAEUSB chip for FPGA programming
if err = f.ctrlProgram(0xA0); err != nil {
return err
}
time.Sleep(10 * time.Millisecond)
if err = f.ctrlProgram(0xA1); err != nil {
return err
}
time.Sleep(10 * time.Millisecond)
// Download bitstream to device
if _, err = io.Copy(f.dev, bitstream); err != nil {
return fmt.Errorf("Failed to download bitstream %v", err)
}
var ready bool
for attempts := 0; attempts < 5; attempts-- {
ready, err = f.IsProgrammed()
if err != nil {
return err
}
if ready {
break
}
time.Sleep(10 * time.Millisecond)
}
// Exit FPGA programming mode
if err = f.ctrlProgram(0xA2); err != nil {
return err
}
if !ready {
return fmt.Errorf("FPGA done pin failed to go high, bad bitstream?")
}
return nil
}
func (f *Fpga) ProgramCwlite() error {
var err error
var bs http.File
if bs, err = hardware.FS.Open("/cwlite_interface.bit"); err != nil {
return fmt.Errorf("Failed opening bitstream file %v", err)
}
defer bs.Close()
return f.Program(bs)
}
func NewFpga(dev UsbDeviceInterface) (*Fpga, error) {
var err error
var programmed bool
f := &Fpga{dev, NewMemory(dev)}
if programmed, err = f.IsProgrammed(); err != nil {
return nil, fmt.Errorf("IsProgrammed failed %v", err)
}
if !programmed {
if err = f.ProgramCwlite(); err != nil {
return nil, fmt.Errorf("ProgramCwlite failed %v", err)
}
}
return f, nil
}