Bluetooth: Add basic packet parsing to Three-wire UART driver
This patch adds basic packet parsing to the Three-wire UART HCI driver
for packets received from the controller.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
diff --git a/drivers/bluetooth/hci_h5.c b/drivers/bluetooth/hci_h5.c
index ae1bd32..ddf7ebb 100644
--- a/drivers/bluetooth/hci_h5.c
+++ b/drivers/bluetooth/hci_h5.c
@@ -34,20 +34,37 @@
#define H5_ACK_TIMEOUT msecs_to_jiffies(250)
+/*
+ * Maximum Three-wire packet:
+ * 4 byte header + max value for 12-bit length + 2 bytes for CRC
+ */
+#define H5_MAX_LEN (4 + 0xfff + 2)
+
+#define SLIP_DELIMITER 0xc0
+#define SLIP_ESC 0xdb
+#define SLIP_ESC_DELIM 0xdc
+#define SLIP_ESC_ESC 0xdd
+
struct h5 {
- struct sk_buff_head unack; /* Unack'ed packets queue */
- struct sk_buff_head rel; /* Reliable packets queue */
- struct sk_buff_head unrel; /* Unreliable packets queue */
+ struct sk_buff_head unack; /* Unack'ed packets queue */
+ struct sk_buff_head rel; /* Reliable packets queue */
+ struct sk_buff_head unrel; /* Unreliable packets queue */
- struct sk_buff *rx_skb;
+ struct sk_buff *rx_skb; /* Receive buffer */
+ size_t rx_pending; /* Expecting more bytes */
+ bool rx_esc; /* SLIP escape mode */
- struct timer_list timer; /* Retransmission timer */
+ int (*rx_func) (struct hci_uart *hu, u8 c);
- bool txack_req;
+ struct timer_list timer; /* Retransmission timer */
- u8 msgq_txseq;
+ bool txack_req;
+
+ u8 msgq_txseq;
};
+static void h5_reset_rx(struct h5 *h5);
+
static void h5_timed_event(unsigned long arg)
{
struct hci_uart *hu = (struct hci_uart *) arg;
@@ -85,6 +102,8 @@
skb_queue_head_init(&h5->rel);
skb_queue_head_init(&h5->unrel);
+ h5_reset_rx(h5);
+
init_timer(&h5->timer);
h5->timer.function = h5_timed_event;
h5->timer.data = (unsigned long) hu;
@@ -107,9 +126,204 @@
return 0;
}
+static void h5_handle_internal_rx(struct hci_uart *hu)
+{
+ BT_DBG("%s", hu->hdev->name);
+}
+
+static void h5_complete_rx_pkt(struct hci_uart *hu)
+{
+ struct h5 *h5 = hu->priv;
+ u8 pkt_type;
+
+ BT_DBG("%s", hu->hdev->name);
+
+ pkt_type = h5->rx_skb->data[1] & 0x0f;
+
+ switch (pkt_type) {
+ case HCI_EVENT_PKT:
+ case HCI_ACLDATA_PKT:
+ case HCI_SCODATA_PKT:
+ bt_cb(h5->rx_skb)->pkt_type = pkt_type;
+
+ /* Remove Three-wire header */
+ skb_pull(h5->rx_skb, 4);
+
+ hci_recv_frame(h5->rx_skb);
+ h5->rx_skb = NULL;
+
+ break;
+
+ default:
+ h5_handle_internal_rx(hu);
+ break;
+ }
+
+ h5_reset_rx(h5);
+}
+
+static int h5_rx_crc(struct hci_uart *hu, unsigned char c)
+{
+ struct h5 *h5 = hu->priv;
+
+ BT_DBG("%s 0x%02hhx", hu->hdev->name, c);
+
+ h5_complete_rx_pkt(hu);
+ h5_reset_rx(h5);
+
+ return 0;
+}
+
+static int h5_rx_payload(struct hci_uart *hu, unsigned char c)
+{
+ struct h5 *h5 = hu->priv;
+ const unsigned char *hdr = h5->rx_skb->data;
+
+ BT_DBG("%s 0x%02hhx", hu->hdev->name, c);
+
+ if ((hdr[0] >> 4) & 0x01) {
+ h5->rx_func = h5_rx_crc;
+ h5->rx_pending = 2;
+ } else {
+ h5_complete_rx_pkt(hu);
+ h5_reset_rx(h5);
+ }
+
+ return 0;
+}
+
+static int h5_rx_3wire_hdr(struct hci_uart *hu, unsigned char c)
+{
+ struct h5 *h5 = hu->priv;
+ const unsigned char *hdr = h5->rx_skb->data;
+
+ BT_DBG("%s 0x%02hhx", hu->hdev->name, c);
+
+ if (((hdr[0] + hdr[1] + hdr[2] + hdr[3]) & 0xff) != 0xff) {
+ BT_ERR("Invalid header checksum");
+ h5_reset_rx(h5);
+ return 0;
+ }
+
+ h5->rx_func = h5_rx_payload;
+ h5->rx_pending = ((hdr[1] >> 4) & 0xff) + (hdr[2] << 4);
+
+ return 0;
+}
+
+static int h5_rx_pkt_start(struct hci_uart *hu, unsigned char c)
+{
+ struct h5 *h5 = hu->priv;
+
+ BT_DBG("%s 0x%02hhx", hu->hdev->name, c);
+
+ if (c == SLIP_DELIMITER)
+ return 1;
+
+ h5->rx_func = h5_rx_3wire_hdr;
+ h5->rx_pending = 4;
+
+ h5->rx_skb = bt_skb_alloc(H5_MAX_LEN, GFP_ATOMIC);
+ if (!h5->rx_skb) {
+ BT_ERR("Can't allocate mem for new packet");
+ h5_reset_rx(h5);
+ return -ENOMEM;
+ }
+
+ h5->rx_skb->dev = (void *) hu->hdev;
+
+ return 0;
+}
+
+static int h5_rx_delimiter(struct hci_uart *hu, unsigned char c)
+{
+ struct h5 *h5 = hu->priv;
+
+ BT_DBG("%s 0x%02hhx", hu->hdev->name, c);
+
+ if (c == SLIP_DELIMITER)
+ h5->rx_func = h5_rx_pkt_start;
+
+ return 1;
+}
+
+static void h5_unslip_one_byte(struct h5 *h5, unsigned char c)
+{
+ const u8 delim = SLIP_DELIMITER, esc = SLIP_ESC;
+ const u8 *byte = &c;
+
+ if (!h5->rx_esc && c == SLIP_ESC) {
+ h5->rx_esc = true;
+ return;
+ }
+
+ if (h5->rx_esc) {
+ switch (c) {
+ case SLIP_ESC_DELIM:
+ byte = &delim;
+ break;
+ case SLIP_ESC_ESC:
+ byte = &esc;
+ break;
+ default:
+ BT_ERR("Invalid esc byte 0x%02hhx", c);
+ h5_reset_rx(h5);
+ return;
+ }
+
+ h5->rx_esc = false;
+ }
+
+ memcpy(skb_put(h5->rx_skb, 1), byte, 1);
+ h5->rx_pending--;
+
+ BT_DBG("unsliped 0x%02hhx", *byte);
+}
+
+static void h5_reset_rx(struct h5 *h5)
+{
+ if (h5->rx_skb) {
+ kfree_skb(h5->rx_skb);
+ h5->rx_skb = NULL;
+ }
+
+ h5->rx_func = h5_rx_delimiter;
+ h5->rx_pending = 0;
+ h5->rx_esc = false;
+}
+
static int h5_recv(struct hci_uart *hu, void *data, int count)
{
- return -ENOSYS;
+ struct h5 *h5 = hu->priv;
+ unsigned char *ptr = data;
+
+ BT_DBG("%s count %d", hu->hdev->name, count);
+
+ while (count > 0) {
+ int processed;
+
+ if (h5->rx_pending > 0) {
+ if (*ptr == SLIP_DELIMITER) {
+ BT_ERR("Too short H5 packet");
+ h5_reset_rx(h5);
+ continue;
+ }
+
+ h5_unslip_one_byte(h5, *ptr);
+
+ ptr++; count--;
+ continue;
+ }
+
+ processed = h5->rx_func(hu, *ptr);
+ if (processed < 0)
+ return processed;
+
+ ptr += processed;
+ count -= processed;
+ }
+
+ return 0;
}
static int h5_enqueue(struct hci_uart *hu, struct sk_buff *skb)
