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hci: contains several corrections needed for HCI on both ninafw and c…
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…yw43439

* separate read and write buffers to accomodate read buffer with pending partial data to be handled
* only read when there is data pending to avoid putting cwy43439 into forever loop
* handle any data in buffer from read that contains data from more than 1 packet
* skip past data for sync packets since we do not handle them anyhow
* some better naming and comments to hopefully clarify a bit what is going on

Signed-off-by: deadprogram <[email protected]>
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@deadprogram
deadprogram committed Nov 21, 2024
1 parent 31a8914 commit c74fb68
Showing 1 changed file with 86 additions and 49 deletions.
135 changes: 86 additions & 49 deletions hci.go
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Original file line number Diff line number Diff line change
Expand Up @@ -136,6 +136,9 @@ type hci struct {
att *att
l2cap *l2cap
buf []byte
pos int
end int
writebuf []byte
address [6]byte
cmdCompleteOpcode uint16
cmdCompleteStatus uint8
Expand All @@ -151,6 +154,7 @@ func newHCI(t hciTransport) *hci {
return &hci{
transport: t,
buf: make([]byte, 256),
writebuf: make([]byte, 256),
}
}

Expand Down Expand Up @@ -188,33 +192,56 @@ func (h *hci) poll() error {
h.transport.startRead()
defer h.transport.endRead()

i := 0
for h.transport.Buffered() > 0 {
sz := h.transport.Buffered()
c := sz + 4 - (sz % 4)
_, err := h.transport.Read(h.buf[i : i+c])
if err != nil {
return err
for h.transport.Buffered() > 0 || h.end > h.pos {
// perform read only if more data is available
available := h.transport.Buffered()
if available > 0 {
aligned := available + (4-(available%4))%4
n, err := h.transport.Read(h.buf[h.end : h.end+aligned])
if err != nil {
return err
}
h.end += n
}
i += sz

done, err := h.processPacket(i)
// do processing
h.pos += 1
done, err := h.processPacket()
switch {
case err == ErrHCIUnknown || err == ErrHCIInvalidPacket || err == ErrHCIUnknownEvent:
case err == ErrHCIInvalidPacket || err == ErrHCIUnknown || err == ErrHCIUnknownEvent:
if debug {
println("hci error:", err.Error(), hex.EncodeToString(h.buf[:i]))
println("hci poll unknown packet:", err.Error(), hex.EncodeToString(h.buf[:h.pos]))
}
i = 0

h.pos = 0
h.end = 0

time.Sleep(5 * time.Millisecond)
case err != nil:
// some other error, so return
h.pos = 0
h.end = 0

return err
case done:
switch {
case h.end > h.pos:
// move remaining data to start of buffer
copy(h.buf[:], h.buf[h.pos:h.end])
h.end -= h.pos
default:
h.end = 0
}

h.pos = 0
return nil
case i+1 >= len(h.buf):
case h.pos > h.end:
if debug {
println("hci error: buffer overflow")
println("hci poll buffer overflow", hex.EncodeToString(h.buf[:h.end]))
}
i = 0
h.pos = 0
h.end = 0

time.Sleep(5 * time.Millisecond)
default:
time.Sleep(1 * time.Millisecond)
Expand All @@ -224,50 +251,60 @@ func (h *hci) poll() error {
return nil
}

func (h *hci) processPacket(i int) (bool, error) {
func (h *hci) processPacket() (bool, error) {
switch h.buf[0] {
case hciACLDataPkt:
if i > hciACLLenPos {
if h.pos > hciACLLenPos {
pktlen := int(binary.LittleEndian.Uint16(h.buf[3:5]))
switch {
case pktlen > len(h.buf):
return true, ErrHCIInvalidPacket
case i >= (hciACLLenPos + pktlen):
case h.end < hciACLLenPos+pktlen:
// need to read more data
return false, nil
case h.pos >= hciACLLenPos+pktlen:
if debug {
println("hci acl data:", i, hex.EncodeToString(h.buf[:1+hciACLLenPos+pktlen]))
println("hci acl data:", h.pos, hex.EncodeToString(h.buf[:hciACLLenPos+pktlen+1]))
}
return true, h.handleACLData(h.buf[1 : 1+hciACLLenPos+pktlen])

h.pos = hciACLLenPos + pktlen + 1
return true, h.handleACLData(h.buf[1:h.pos])
}
}

case hciEventPkt:
if i > hciEvtLenPos {
if h.pos > hciEvtLenPos {
pktlen := int(h.buf[hciEvtLenPos])

switch {
case pktlen > len(h.buf):
return true, ErrHCIInvalidPacket
case i >= (hciEvtLenPos + pktlen):
case h.end < hciEvtLenPos+pktlen:
// need to read more data
return false, nil
case h.pos >= hciEvtLenPos+pktlen:
if debug {
println("hci event data:", i, hex.EncodeToString(h.buf[:1+hciEvtLenPos+pktlen]))
println("hci event data:", h.pos, hex.EncodeToString(h.buf[:hciEvtLenPos+pktlen+1]))
}
return true, h.handleEventData(h.buf[1 : 1+hciEvtLenPos+pktlen])

h.pos = hciEvtLenPos + pktlen + 1
return true, h.handleEventData(h.buf[1:h.pos])
}
}

case hciSynchronousDataPkt:
// not supported by BLE, so ignore
if i > 3 {
if h.pos > 3 {
pktlen := int(h.buf[3])
if debug {
println("hci synchronous data:", i, pktlen, hex.EncodeToString(h.buf[:1+3+pktlen]))
println("hci synchronous data:", h.pos, pktlen, hex.EncodeToString(h.buf[:1+3+pktlen]))
}

// move to next packet
h.pos = 1 + 3 + pktlen

return true, nil
}

default:
if debug {
println("unknown packet data:", hex.EncodeToString(h.buf[0:i]))
println("unknown packet data:", h.pos, h.end, hex.EncodeToString(h.buf[:h.pos]))
}
return true, ErrHCIUnknown
}
Expand Down Expand Up @@ -443,12 +480,12 @@ func (h *hci) sendCommandWithParams(opcode uint16, params []byte) error {
println("hci send command", opcode, hex.EncodeToString(params))
}

h.buf[0] = hciCommandPkt
binary.LittleEndian.PutUint16(h.buf[1:], opcode)
h.buf[3] = byte(len(params))
copy(h.buf[4:], params)
h.writebuf[0] = hciCommandPkt
binary.LittleEndian.PutUint16(h.writebuf[1:], opcode)
h.writebuf[3] = byte(len(params))
copy(h.writebuf[4:], params)

if _, err := h.write(h.buf[:4+len(params)]); err != nil {
if _, err := h.write(h.writebuf[:4+len(params)]); err != nil {
return err
}

Expand All @@ -474,12 +511,12 @@ func (h *hci) sendWithoutResponse(opcode uint16, params []byte) error {
println("hci send without response command", opcode, hex.EncodeToString(params))
}

h.buf[0] = hciCommandPkt
binary.LittleEndian.PutUint16(h.buf[1:], opcode)
h.buf[3] = byte(len(params))
copy(h.buf[4:], params)
h.writebuf[0] = hciCommandPkt
binary.LittleEndian.PutUint16(h.writebuf[1:], opcode)
h.writebuf[3] = byte(len(params))
copy(h.writebuf[4:], params)

if _, err := h.write(h.buf[:4+len(params)]); err != nil {
if _, err := h.write(h.writebuf[:4+len(params)]); err != nil {
return err
}

Expand All @@ -490,19 +527,19 @@ func (h *hci) sendWithoutResponse(opcode uint16, params []byte) error {
}

func (h *hci) sendAclPkt(handle uint16, cid uint8, data []byte) error {
h.buf[0] = hciACLDataPkt
binary.LittleEndian.PutUint16(h.buf[1:], handle)
binary.LittleEndian.PutUint16(h.buf[3:], uint16(len(data)+4))
binary.LittleEndian.PutUint16(h.buf[5:], uint16(len(data)))
binary.LittleEndian.PutUint16(h.buf[7:], uint16(cid))
h.writebuf[0] = hciACLDataPkt
binary.LittleEndian.PutUint16(h.writebuf[1:], handle)
binary.LittleEndian.PutUint16(h.writebuf[3:], uint16(len(data)+4))
binary.LittleEndian.PutUint16(h.writebuf[5:], uint16(len(data)))
binary.LittleEndian.PutUint16(h.writebuf[7:], uint16(cid))

copy(h.buf[9:], data)
copy(h.writebuf[9:], data)

if debug {
println("hci send acl data", handle, cid, hex.EncodeToString(h.buf[:9+len(data)]))
println("hci send acl data", handle, cid, hex.EncodeToString(h.writebuf[:9+len(data)]))
}

if _, err := h.write(h.buf[:9+len(data)]); err != nil {
if _, err := h.write(h.writebuf[:9+len(data)]); err != nil {
return err
}

Expand Down

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