github.com/mvdan/u-root-coreutils@v0.0.0-20230122170626-c2eef2898555/cmds/core/pci/pci.go

// Copyright 2012-2017 the u-root Authors. All rights reserved
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

//go:build !plan9
// +build !plan9

// pci: show pci bus vendor ids and other info
//
// Description:
//
//	List the PCI bus, with names if possible.
//
// Options:
//
//	-n: just show numbers
//	-c: dump config space
//	-s: specify glob for choosing devices.
package main

import (
	"encoding/json"
	"fmt"
	"io"
	"log"
	"os"
	"strconv"
	"strings"

	flag "github.com/pborman/getopt/v2"
	"github.com/mvdan/u-root-coreutils/pkg/pci"
)

var (
	numbers   = flag.Bool('n', "Show numeric IDs")
	devs      = flag.StringLong("select", 's', "*", "Devices to match")
	dumpJSON  = flag.BoolLong("json", 'j', "Dump the bus in JSON")
	verbosity = flag.Counter('v', "verbosity")
	hexdump   = flag.Counter('x', "hexdump the config space")
	readJSON  = flag.StringLong("JSON", 'J', "", "Read JSON in instead of /sys")
)

var format = map[int]string{
	32: "%08x:%08x",
	16: "%08x:%04x",
	8:  "%08x:%02x",
}

// maybe we need a better syntax than the standard pcitools?
func registers(d pci.Devices, cmds ...string) {
	var justCheck bool
	for _, c := range cmds {
		// TODO: replace this nonsense with a state machine.
		// Split into register and value
		rv := strings.Split(c, "=")
		if len(rv) != 1 && len(rv) != 2 {
			log.Printf("%v: only one = allowed. Due to this error no more commands will be issued", c)
			justCheck = true
			continue
		}

		// Split into register offset and size
		rs := strings.Split(rv[0], ".")
		if len(rs) != 1 && len(rs) != 2 {
			log.Printf("%v: only one . allowed. Due to this error no more commands will be issued", rv[1])
			justCheck = true
			continue
		}
		s := 32
		if len(rs) == 2 {
			switch rs[1] {
			default:
				log.Printf("Bad size: %v. Due to this error no more commands will be issued", rs[1])
				justCheck = true
				continue
			case "l":
			case "w":
				s = 16
			case "b":
				s = 8
			}
		}
		if justCheck {
			continue
		}
		reg, err := strconv.ParseUint(rs[0], 0, 16)
		if err != nil {
			log.Printf("%v:%v. Due to this error no more commands will be issued", rs[0], err)
			justCheck = true
			continue
		}
		if len(rv) == 1 {
			v, err := d.ReadConfigRegister(int64(reg), int64(s))
			if err != nil {
				log.Printf("%v:%v. Due to this error no more commands will be issued", rv[0], err)
				justCheck = true
				continue
			}
			// Should this go in the package somewhere? Not sure.
			for i := range v {
				d[i].ExtraInfo = append(d[i].ExtraInfo, fmt.Sprintf(format[s], reg, v[i]))
			}
		}
		if len(rv) == 2 {
			val, err := strconv.ParseUint(rv[1], 0, s)
			if err != nil {
				log.Printf("%v. Due to this error no more commands will be issued", err)
				justCheck = true
				continue
			}
			if err := d.WriteConfigRegister(int64(reg), int64(s), val); err != nil {
				log.Printf("%v:%v. Due to this error no more commands will be issued", rv[1], err)
				justCheck = true
				continue
			}
		}

	}
}

func pciExecution(w io.Writer, args ...string) error {
	var dumpSize int
	switch *hexdump {
	case 4:
		dumpSize = 4096
	case 3:
		dumpSize = 256
	case 2: // lspci disallows this value
		dumpSize = 256
	case 1:
		dumpSize = 64
	}
	r, err := pci.NewBusReader(strings.Split(*devs, ",")...)
	if err != nil {
		return err
	}

	var d pci.Devices
	if len(*readJSON) != 0 {
		b, err := os.ReadFile(*readJSON)
		if err != nil {
			return err
		}
		if err := json.Unmarshal(b, &d); err != nil {
			return err
		}

	} else {
		if d, err = r.Read(); err != nil {
			return err
		}
	}

	if !*numbers || *dumpJSON {
		d.SetVendorDeviceName()
	}
	if len(args) > 0 {
		registers(d, args...)
	}
	if *dumpJSON {
		o, err := json.MarshalIndent(d, "", "\t")
		if err != nil {
			return err
		}
		fmt.Fprintf(w, "%s", string(o))
		return nil
	}
	if err := d.Print(w, *verbosity, dumpSize); err != nil {
		return err
	}
	return nil
}

func main() {
	flag.Parse()
	if err := pciExecution(os.Stdout, flag.Args()...); err != nil {
		log.Fatal(err)
	}
}