Find ST-Link mount for serial port on Linux

CL: mos: Find ST-Link mount for serial port on Linux

PUBLISHED_FROM=2225a5211c90137a53bd5fe7073d2c38068d59d9

mos/flash.go

@@ -18,6 +18,7 @@ import (
 	espFlasher "cesanta.com/mos/flash/esp/flasher"
 	"cesanta.com/mos/flash/stm32"
 	"github.com/cesanta/errors"
+	"github.com/golang/glog"
 	flag "github.com/spf13/pflag"
 )
 
@@ -135,14 +136,20 @@ func flash(ctx context.Context, devConn *dev.DevConn) error {
 		// But for now, we'll just find mountpoints that sort of look like STLink...
 		port = *portFlag
 		if port == "auto" || (strings.HasPrefix(port, "/dev/") || strings.HasPrefix(port, "COM")) {
-			mm, err := stm32.FindSTLinkMounts()
+			port, err = stm32.GetSTLinkMountForPort(port)
 			if err != nil {
-				return errors.Trace(err)
+				glog.Infof("Did not find port corresponding to %s: %s", *portFlag, err)
+				mm, err := stm32.GetSTLinkMounts()
+				if err != nil {
+					return errors.Trace(err)
+				}
+				if len(mm) == 0 {
+					return errors.Errorf("No STM32 devices found")
+				}
+				port = mm[0]
+			} else {
+				glog.Infof("%s -> %s", *portFlag, port)
 			}
-			if len(mm) == 0 {
-				return errors.Errorf("No STM32 devices found")
-			}
-			port = mm[0]
 		}
 		stm32FlashOpts.ShareName = port
 		err = stm32.Flash(fw, &stm32FlashOpts)

mos/flash/stm32/flasher-share.go

@@ -4,8 +4,10 @@ import (
 	"io/ioutil"
 	"os"
 	"path/filepath"
+	"strings"
 	"time"
 
+	"cesanta.com/common/go/ourutil"
 	"cesanta.com/mos/flash/common"
 	"github.com/cesanta/errors"
 	"github.com/golang/glog"
@@ -15,6 +17,25 @@ var (
 	stlinkDevPrefixes = []string{"DIS_", "NODE_"}
 )
 
+func getSTLinkMountsInDir(dir string) ([]string, error) {
+	glog.V(1).Infof("Looking for ST-Link devices under %q", dir)
+	ee, err := ioutil.ReadDir(dir)
+	if err != nil {
+		return nil, errors.Annotatef(err, "failed to list %q", dir)
+	}
+	var res []string
+	for _, e := range ee {
+		for _, p := range stlinkDevPrefixes {
+			if strings.HasPrefix(e.Name(), p) {
+				n := filepath.Join(dir, e.Name())
+				ourutil.Reportf("Found STLink mount: %s", n)
+				res = append(res, n)
+			}
+		}
+	}
+	return res, nil
+}
+
 type FlashOpts struct {
 	ShareName string
 	Timeout   time.Duration

mos/flash/stm32/flasher_darwin.go

@@ -0,0 +1,10 @@
+package stm32
+
+func GetSTLinkMountForPort(port string) (string, error) {
+	// TODO(rojer)
+	return "", errors.NotImplementedf("GetSTLinkMountForPort")
+}
+
+func GetSTLinkMounts() ([]string, error) {
+	return getSTLinkMountsInDir("/Volumes")
+}

mos/flash/stm32/flasher_linux.go

@@ -0,0 +1,63 @@
+package stm32
+
+import (
+	"bufio"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/cesanta/errors"
+	"github.com/golang/glog"
+)
+
+func GetSTLinkMountForPort(port string) (string, error) {
+	port, _ = filepath.EvalSymlinks(port)
+	// Find the USB device directory corresponding to the TTY device.
+	usbDevDir := ""
+	ports, _ := filepath.Glob("/sys/bus/usb/devices/*/*/tty/*")
+	for _, p := range ports {
+		// /sys/bus/usb/devices/NNN/NNN:1.2/tty/ttyACMx (CDC is interface 1, endpoint 2).
+		if filepath.Base(p) == filepath.Base(port) {
+			dd1, _ := filepath.Split(p)
+			dd2, _ := filepath.Split(filepath.Clean(dd1))
+			dd3, _ := filepath.Split(filepath.Clean(dd2))
+			usbDevDir = filepath.Clean(dd3) // /sys/bus/usb/devices/NNN
+			glog.V(1).Infof("%s -> %s -> %s", port, p, usbDevDir)
+		}
+	}
+	if usbDevDir == "" {
+		return "", errors.Errorf("no USB device found for %s", port)
+	}
+	// Find the block device name associated with this USB device.
+	// Expand /sys/bus/usb/devices/NNN/*/*/*/*/block, it will contain the list of devices (only one).
+	blockDevs, _ := filepath.Glob(filepath.Join(usbDevDir, "*", "*", "*", "*", "block", "*"))
+	if len(blockDevs) == 0 {
+		return "", errors.Errorf("no block device found for %s", port)
+	}
+	dev := filepath.Join("/dev", filepath.Base(blockDevs[0]))
+	// Now find mount point for this device.
+
+	glog.V(1).Infof("%s -> %s", port, dev)
+	f, err := os.Open("/proc/mounts")
+	if err != nil {
+		return "", errors.Annotatef(err, "failed to open list of mounts")
+	}
+	defer f.Close()
+	mp := ""
+	sc := bufio.NewScanner(f)
+	for sc.Scan() {
+		parts := strings.Split(sc.Text(), " ")
+		if parts[0] == dev {
+			mp = parts[1]
+			break
+		}
+	}
+	if mp == "" {
+		return "", errors.Errorf("%s is not mounted", dev)
+	}
+	return mp, nil
+}
+
+func GetSTLinkMounts() ([]string, error) {
+	return getSTLinkMountsInDir(filepath.Join("/", "media", os.Getenv("USER")))
+}

mos/flash/stm32/flasher_windows.go

@@ -16,8 +16,9 @@ import (
 	"golang.org/x/sys/windows"
 )
 
-// Enumerate drives and find ones that have name start with one of the known prefixes.
-func FindSTLinkMounts() ([]string, error) {
+// GetSTLinkMounts enumerated drives and finds ones that have
+// a name starting with one of the known prefixes.
+func GetSTLinkMounts() ([]string, error) {
 	drivesBitMask, err := windows.GetLogicalDrives()
 	if err != nil {
 		return nil, errors.Annotatef(err, "GetLogicalDrives")
@@ -63,3 +64,8 @@ func getDriveInfo(drive string) (string, string, uint32, error) {
 
 	return syscall.UTF16ToString(volName), syscall.UTF16ToString(fsName), volSerial, nil
 }
+
+func GetSTLinkMountForPort(port string) (string, error) {
+	// TODO(rojer)
+	return "", errors.NotImplementedf("GetSTLinkMountForPort")
+}