diff options
Diffstat (limited to 'net/nfc/hci/shdlc.c')
| -rw-r--r-- | net/nfc/hci/shdlc.c | 945 |
1 files changed, 945 insertions, 0 deletions
diff --git a/net/nfc/hci/shdlc.c b/net/nfc/hci/shdlc.c new file mode 100644 index 00000000000..923bdf7c26d --- /dev/null +++ b/net/nfc/hci/shdlc.c @@ -0,0 +1,945 @@ +/* + * Copyright (C) 2012 Intel Corporation. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the + * Free Software Foundation, Inc., + * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + */ + +#define pr_fmt(fmt) "shdlc: %s: " fmt, __func__ + +#include <linux/sched.h> +#include <linux/export.h> +#include <linux/wait.h> +#include <linux/crc-ccitt.h> +#include <linux/slab.h> +#include <linux/skbuff.h> + +#include <net/nfc/hci.h> +#include <net/nfc/shdlc.h> + +#define SHDLC_LLC_HEAD_ROOM 2 +#define SHDLC_LLC_TAIL_ROOM 2 + +#define SHDLC_MAX_WINDOW 4 +#define SHDLC_SREJ_SUPPORT false + +#define SHDLC_CONTROL_HEAD_MASK 0xe0 +#define SHDLC_CONTROL_HEAD_I 0x80 +#define SHDLC_CONTROL_HEAD_I2 0xa0 +#define SHDLC_CONTROL_HEAD_S 0xc0 +#define SHDLC_CONTROL_HEAD_U 0xe0 + +#define SHDLC_CONTROL_NS_MASK 0x38 +#define SHDLC_CONTROL_NR_MASK 0x07 +#define SHDLC_CONTROL_TYPE_MASK 0x18 + +#define SHDLC_CONTROL_M_MASK 0x1f + +enum sframe_type { + S_FRAME_RR = 0x00, + S_FRAME_REJ = 0x01, + S_FRAME_RNR = 0x02, + S_FRAME_SREJ = 0x03 +}; + +enum uframe_modifier { + U_FRAME_UA = 0x06, + U_FRAME_RSET = 0x19 +}; + +#define SHDLC_CONNECT_VALUE_MS 5 +#define SHDLC_T1_VALUE_MS(w) ((5 * w) / 4) +#define SHDLC_T2_VALUE_MS 300 + +#define SHDLC_DUMP_SKB(info, skb) \ +do { \ + pr_debug("%s:\n", info); \ + print_hex_dump(KERN_DEBUG, "shdlc: ", DUMP_PREFIX_OFFSET, \ + 16, 1, skb->data, skb->len, 0); \ +} while (0) + +/* checks x < y <= z modulo 8 */ +static bool nfc_shdlc_x_lt_y_lteq_z(int x, int y, int z) +{ + if (x < z) + return ((x < y) && (y <= z)) ? true : false; + else + return ((y > x) || (y <= z)) ? true : false; +} + +/* checks x <= y < z modulo 8 */ +static bool nfc_shdlc_x_lteq_y_lt_z(int x, int y, int z) +{ + if (x <= z) + return ((x <= y) && (y < z)) ? true : false; + else /* x > z -> z+8 > x */ + return ((y >= x) || (y < z)) ? true : false; +} + +static struct sk_buff *nfc_shdlc_alloc_skb(struct nfc_shdlc *shdlc, + int payload_len) +{ + struct sk_buff *skb; + + skb = alloc_skb(shdlc->client_headroom + SHDLC_LLC_HEAD_ROOM + + shdlc->client_tailroom + SHDLC_LLC_TAIL_ROOM + + payload_len, GFP_KERNEL); + if (skb) + skb_reserve(skb, shdlc->client_headroom + SHDLC_LLC_HEAD_ROOM); + + return skb; +} + +static void nfc_shdlc_add_len_crc(struct sk_buff *skb) +{ + u16 crc; + int len; + + len = skb->len + 2; + *skb_push(skb, 1) = len; + + crc = crc_ccitt(0xffff, skb->data, skb->len); + crc = ~crc; + *skb_put(skb, 1) = crc & 0xff; + *skb_put(skb, 1) = crc >> 8; +} + +/* immediately sends an S frame. */ +static int nfc_shdlc_send_s_frame(struct nfc_shdlc *shdlc, + enum sframe_type sframe_type, int nr) +{ + int r; + struct sk_buff *skb; + + pr_debug("sframe_type=%d nr=%d\n", sframe_type, nr); + + skb = nfc_shdlc_alloc_skb(shdlc, 0); + if (skb == NULL) + return -ENOMEM; + + *skb_push(skb, 1) = SHDLC_CONTROL_HEAD_S | (sframe_type << 3) | nr; + + nfc_shdlc_add_len_crc(skb); + + r = shdlc->ops->xmit(shdlc, skb); + + kfree_skb(skb); + + return r; +} + +/* immediately sends an U frame. skb may contain optional payload */ +static int nfc_shdlc_send_u_frame(struct nfc_shdlc *shdlc, + struct sk_buff *skb, + enum uframe_modifier uframe_modifier) +{ + int r; + + pr_debug("uframe_modifier=%d\n", uframe_modifier); + + *skb_push(skb, 1) = SHDLC_CONTROL_HEAD_U | uframe_modifier; + + nfc_shdlc_add_len_crc(skb); + + r = shdlc->ops->xmit(shdlc, skb); + + kfree_skb(skb); + + return r; +} + +/* + * Free ack_pending frames until y_nr - 1, and reset t2 according to + * the remaining oldest ack_pending frame sent time + */ +static void nfc_shdlc_reset_t2(struct nfc_shdlc *shdlc, int y_nr) +{ + struct sk_buff *skb; + int dnr = shdlc->dnr; /* MUST initially be < y_nr */ + + pr_debug("release ack pending up to frame %d excluded\n", y_nr); + + while (dnr != y_nr) { + pr_debug("release ack pending frame %d\n", dnr); + + skb = skb_dequeue(&shdlc->ack_pending_q); + kfree_skb(skb); + + dnr = (dnr + 1) % 8; + } + + if (skb_queue_empty(&shdlc->ack_pending_q)) { + if (shdlc->t2_active) { + del_timer_sync(&shdlc->t2_timer); + shdlc->t2_active = false; + + pr_debug + ("All sent frames acked. Stopped T2(retransmit)\n"); + } + } else { + skb = skb_peek(&shdlc->ack_pending_q); + + mod_timer(&shdlc->t2_timer, *(unsigned long *)skb->cb + + msecs_to_jiffies(SHDLC_T2_VALUE_MS)); + shdlc->t2_active = true; + + pr_debug + ("Start T2(retransmit) for remaining unacked sent frames\n"); + } +} + +/* + * Receive validated frames from lower layer. skb contains HCI payload only. + * Handle according to algorithm at spec:10.8.2 + */ +static void nfc_shdlc_rcv_i_frame(struct nfc_shdlc *shdlc, + struct sk_buff *skb, int ns, int nr) +{ + int x_ns = ns; + int y_nr = nr; + + pr_debug("recvd I-frame %d, remote waiting frame %d\n", ns, nr); + + if (shdlc->state != SHDLC_CONNECTED) + goto exit; + + if (x_ns != shdlc->nr) { + nfc_shdlc_send_s_frame(shdlc, S_FRAME_REJ, shdlc->nr); + goto exit; + } + + if (shdlc->t1_active == false) { + shdlc->t1_active = true; + mod_timer(&shdlc->t1_timer, + msecs_to_jiffies(SHDLC_T1_VALUE_MS(shdlc->w))); + pr_debug("(re)Start T1(send ack)\n"); + } + + if (skb->len) { + nfc_hci_recv_frame(shdlc->hdev, skb); + skb = NULL; + } + + shdlc->nr = (shdlc->nr + 1) % 8; + + if (nfc_shdlc_x_lt_y_lteq_z(shdlc->dnr, y_nr, shdlc->ns)) { + nfc_shdlc_reset_t2(shdlc, y_nr); + + shdlc->dnr = y_nr; + } + +exit: + if (skb) + kfree_skb(skb); +} + +static void nfc_shdlc_rcv_ack(struct nfc_shdlc *shdlc, int y_nr) +{ + pr_debug("remote acked up to frame %d excluded\n", y_nr); + + if (nfc_shdlc_x_lt_y_lteq_z(shdlc->dnr, y_nr, shdlc->ns)) { + nfc_shdlc_reset_t2(shdlc, y_nr); + shdlc->dnr = y_nr; + } +} + +static void nfc_shdlc_requeue_ack_pending(struct nfc_shdlc *shdlc) +{ + struct sk_buff *skb; + + pr_debug("ns reset to %d\n", shdlc->dnr); + + while ((skb = skb_dequeue_tail(&shdlc->ack_pending_q))) { + skb_pull(skb, 2); /* remove len+control */ + skb_trim(skb, skb->len - 2); /* remove crc */ + skb_queue_head(&shdlc->send_q, skb); + } + shdlc->ns = shdlc->dnr; +} + +static void nfc_shdlc_rcv_rej(struct nfc_shdlc *shdlc, int y_nr) +{ + struct sk_buff *skb; + + pr_debug("remote asks retransmition from frame %d\n", y_nr); + + if (nfc_shdlc_x_lteq_y_lt_z(shdlc->dnr, y_nr, shdlc->ns)) { + if (shdlc->t2_active) { + del_timer_sync(&shdlc->t2_timer); + shdlc->t2_active = false; + pr_debug("Stopped T2(retransmit)\n"); + } + + if (shdlc->dnr != y_nr) { + while ((shdlc->dnr = ((shdlc->dnr + 1) % 8)) != y_nr) { + skb = skb_dequeue(&shdlc->ack_pending_q); + kfree_skb(skb); + } + } + + nfc_shdlc_requeue_ack_pending(shdlc); + } +} + +/* See spec RR:10.8.3 REJ:10.8.4 */ +static void nfc_shdlc_rcv_s_frame(struct nfc_shdlc *shdlc, + enum sframe_type s_frame_type, int nr) +{ + struct sk_buff *skb; + + if (shdlc->state != SHDLC_CONNECTED) + return; + + switch (s_frame_type) { + case S_FRAME_RR: + nfc_shdlc_rcv_ack(shdlc, nr); + if (shdlc->rnr == true) { /* see SHDLC 10.7.7 */ + shdlc->rnr = false; + if (shdlc->send_q.qlen == 0) { + skb = nfc_shdlc_alloc_skb(shdlc, 0); + if (skb) + skb_queue_tail(&shdlc->send_q, skb); + } + } + break; + case S_FRAME_REJ: + nfc_shdlc_rcv_rej(shdlc, nr); + break; + case S_FRAME_RNR: + nfc_shdlc_rcv_ack(shdlc, nr); + shdlc->rnr = true; + break; + default: + break; + } +} + +static void nfc_shdlc_connect_complete(struct nfc_shdlc *shdlc, int r) +{ + pr_debug("result=%d\n", r); + + del_timer_sync(&shdlc->connect_timer); + + if (r == 0) { + shdlc->ns = 0; + shdlc->nr = 0; + shdlc->dnr = 0; + + shdlc->state = SHDLC_CONNECTED; + } else { + shdlc->state = SHDLC_DISCONNECTED; + + /* + * TODO: Could it be possible that there are pending + * executing commands that are waiting for connect to complete + * before they can be carried? As connect is a blocking + * operation, it would require that the userspace process can + * send commands on the same device from a second thread before + * the device is up. I don't think that is possible, is it? + */ + } + + shdlc->connect_result = r; + + wake_up(shdlc->connect_wq); +} + +static int nfc_shdlc_connect_initiate(struct nfc_shdlc *shdlc) +{ + struct sk_buff *skb; + + pr_debug("\n"); + + skb = nfc_shdlc_alloc_skb(shdlc, 2); + if (skb == NULL) + return -ENOMEM; + + *skb_put(skb, 1) = SHDLC_MAX_WINDOW; + *skb_put(skb, 1) = SHDLC_SREJ_SUPPORT ? 1 : 0; + + return nfc_shdlc_send_u_frame(shdlc, skb, U_FRAME_RSET); +} + +static int nfc_shdlc_connect_send_ua(struct nfc_shdlc *shdlc) +{ + struct sk_buff *skb; + + pr_debug("\n"); + + skb = nfc_shdlc_alloc_skb(shdlc, 0); + if (skb == NULL) + return -ENOMEM; + + return nfc_shdlc_send_u_frame(shdlc, skb, U_FRAME_UA); +} + +static void nfc_shdlc_rcv_u_frame(struct nfc_shdlc *shdlc, + struct sk_buff *skb, + enum uframe_modifier u_frame_modifier) +{ + u8 w = SHDLC_MAX_WINDOW; + bool srej_support = SHDLC_SREJ_SUPPORT; + int r; + + pr_debug("u_frame_modifier=%d\n", u_frame_modifier); + + switch (u_frame_modifier) { + case U_FRAME_RSET: + if (shdlc->state == SHDLC_NEGOCIATING) { + /* we sent RSET, but chip wants to negociate */ + if (skb->len > 0) + w = skb->data[0]; + + if (skb->len > 1) + srej_support = skb->data[1] & 0x01 ? true : + false; + + if ((w <= SHDLC_MAX_WINDOW) && + (SHDLC_SREJ_SUPPORT || (srej_support == false))) { + shdlc->w = w; + shdlc->srej_support = srej_support; + r = nfc_shdlc_connect_send_ua(shdlc); + nfc_shdlc_connect_complete(shdlc, r); + } + } else if (shdlc->state > SHDLC_NEGOCIATING) { + /* + * TODO: Chip wants to reset link + * send ua, empty skb lists, reset counters + * propagate info to HCI layer + */ + } + break; + case U_FRAME_UA: + if ((shdlc->state == SHDLC_CONNECTING && + shdlc->connect_tries > 0) || + (shdlc->state == SHDLC_NEGOCIATING)) + nfc_shdlc_connect_complete(shdlc, 0); + break; + default: + break; + } + + kfree_skb(skb); +} + +static void nfc_shdlc_handle_rcv_queue(struct nfc_shdlc *shdlc) +{ + struct sk_buff *skb; + u8 control; + int nr; + int ns; + enum sframe_type s_frame_type; + enum uframe_modifier u_frame_modifier; + + if (shdlc->rcv_q.qlen) + pr_debug("rcvQlen=%d\n", shdlc->rcv_q.qlen); + + while ((skb = skb_dequeue(&shdlc->rcv_q)) != NULL) { + control = skb->data[0]; + skb_pull(skb, 1); + switch (control & SHDLC_CONTROL_HEAD_MASK) { + case SHDLC_CONTROL_HEAD_I: + case SHDLC_CONTROL_HEAD_I2: + ns = (control & SHDLC_CONTROL_NS_MASK) >> 3; + nr = control & SHDLC_CONTROL_NR_MASK; + nfc_shdlc_rcv_i_frame(shdlc, skb, ns, nr); + break; + case SHDLC_CONTROL_HEAD_S: + s_frame_type = (control & SHDLC_CONTROL_TYPE_MASK) >> 3; + nr = control & SHDLC_CONTROL_NR_MASK; + nfc_shdlc_rcv_s_frame(shdlc, s_frame_type, nr); + kfree_skb(skb); + break; + case SHDLC_CONTROL_HEAD_U: + u_frame_modifier = control & SHDLC_CONTROL_M_MASK; + nfc_shdlc_rcv_u_frame(shdlc, skb, u_frame_modifier); + break; + default: + pr_err("UNKNOWN Control=%d\n", control); + kfree_skb(skb); + break; + } + } +} + +static int nfc_shdlc_w_used(int ns, int dnr) +{ + int unack_count; + + if (dnr <= ns) + unack_count = ns - dnr; + else + unack_count = 8 - dnr + ns; + + return unack_count; +} + +/* Send frames according to algorithm at spec:10.8.1 */ +static void nfc_shdlc_handle_send_queue(struct nfc_shdlc *shdlc) +{ + struct sk_buff *skb; + int r; + unsigned long time_sent; + + if (shdlc->send_q.qlen) + pr_debug + ("sendQlen=%d ns=%d dnr=%d rnr=%s w_room=%d unackQlen=%d\n", + shdlc->send_q.qlen, shdlc->ns, shdlc->dnr, + shdlc->rnr == false ? "false" : "true", + shdlc->w - nfc_shdlc_w_used(shdlc->ns, shdlc->dnr), + shdlc->ack_pending_q.qlen); + + while (shdlc->send_q.qlen && shdlc->ack_pending_q.qlen < shdlc->w && + (shdlc->rnr == false)) { + + if (shdlc->t1_active) { + del_timer_sync(&shdlc->t1_timer); + shdlc->t1_active = false; + pr_debug("Stopped T1(send ack)\n"); + } + + skb = skb_dequeue(&shdlc->send_q); + + *skb_push(skb, 1) = SHDLC_CONTROL_HEAD_I | (shdlc->ns << 3) | + shdlc->nr; + + pr_debug("Sending I-Frame %d, waiting to rcv %d\n", shdlc->ns, + shdlc->nr); + /* SHDLC_DUMP_SKB("shdlc frame written", skb); */ + + nfc_shdlc_add_len_crc(skb); + + r = shdlc->ops->xmit(shdlc, skb); + if (r < 0) { + /* + * TODO: Cannot send, shdlc machine is dead, we + * must propagate the information up to HCI. + */ + shdlc->hard_fault = r; + break; + } + + shdlc->ns = (shdlc->ns + 1) % 8; + + time_sent = jiffies; + *(unsigned long *)skb->cb = time_sent; + + skb_queue_tail(&shdlc->ack_pending_q, skb); + + if (shdlc->t2_active == false) { + shdlc->t2_active = true; + mod_timer(&shdlc->t2_timer, time_sent + + msecs_to_jiffies(SHDLC_T2_VALUE_MS)); + pr_debug("Started T2 (retransmit)\n"); + } + } +} + +static void nfc_shdlc_connect_timeout(unsigned long data) +{ + struct nfc_shdlc *shdlc = (struct nfc_shdlc *)data; + + pr_debug("\n"); + + queue_work(shdlc->sm_wq, &shdlc->sm_work); +} + +static void nfc_shdlc_t1_timeout(unsigned long data) +{ + struct nfc_shdlc *shdlc = (struct nfc_shdlc *)data; + + pr_debug("SoftIRQ: need to send ack\n"); + + queue_work(shdlc->sm_wq, &shdlc->sm_work); +} + +static void nfc_shdlc_t2_timeout(unsigned long data) +{ + struct nfc_shdlc *shdlc = (struct nfc_shdlc *)data; + + pr_debug("SoftIRQ: need to retransmit\n"); + + queue_work(shdlc->sm_wq, &shdlc->sm_work); +} + +static void nfc_shdlc_sm_work(struct work_struct *work) +{ + struct nfc_shdlc *shdlc = container_of(work, struct nfc_shdlc, sm_work); + int r; + + pr_debug("\n"); + + mutex_lock(&shdlc->state_mutex); + + switch (shdlc->state) { + case SHDLC_DISCONNECTED: + skb_queue_purge(&shdlc->rcv_q); + skb_queue_purge(&shdlc->send_q); + skb_queue_purge(&shdlc->ack_pending_q); + break; + case SHDLC_CONNECTING: + if (shdlc->connect_tries++ < 5) + r = nfc_shdlc_connect_initiate(shdlc); + else + r = -ETIME; + if (r < 0) + nfc_shdlc_connect_complete(shdlc, r); + else { + mod_timer(&shdlc->connect_timer, jiffies + + msecs_to_jiffies(SHDLC_CONNECT_VALUE_MS)); + + shdlc->state = SHDLC_NEGOCIATING; + } + break; + case SHDLC_NEGOCIATING: + if (timer_pending(&shdlc->connect_timer) == 0) { + shdlc->state = SHDLC_CONNECTING; + queue_work(shdlc->sm_wq, &shdlc->sm_work); + } + + nfc_shdlc_handle_rcv_queue(shdlc); + break; + case SHDLC_CONNECTED: + nfc_shdlc_handle_rcv_queue(shdlc); + nfc_shdlc_handle_send_queue(shdlc); + + if (shdlc->t1_active && timer_pending(&shdlc->t1_timer) == 0) { + pr_debug + ("Handle T1(send ack) elapsed (T1 now inactive)\n"); + + shdlc->t1_active = false; + r = nfc_shdlc_send_s_frame(shdlc, S_FRAME_RR, + shdlc->nr); + if (r < 0) + shdlc->hard_fault = r; + } + + if (shdlc->t2_active && timer_pending(&shdlc->t2_timer) == 0) { + pr_debug + ("Handle T2(retransmit) elapsed (T2 inactive)\n"); + + shdlc->t2_active = false; + + nfc_shdlc_requeue_ack_pending(shdlc); + nfc_shdlc_handle_send_queue(shdlc); + } + + if (shdlc->hard_fault) { + /* + * TODO: Handle hard_fault that occured during + * this invocation of the shdlc worker + */ + } + break; + default: + break; + } + mutex_unlock(&shdlc->state_mutex); +} + +/* + * Called from syscall context to establish shdlc link. Sleeps until + * link is ready or failure. + */ +static int nfc_shdlc_connect(struct nfc_shdlc *shdlc) +{ + DECLARE_WAIT_QUEUE_HEAD_ONSTACK(connect_wq); + + pr_debug("\n"); + + mutex_lock(&shdlc->state_mutex); + + shdlc->state = SHDLC_CONNECTING; + shdlc->connect_wq = &connect_wq; + shdlc->connect_tries = 0; + shdlc->connect_result = 1; + + mutex_unlock(&shdlc->state_mutex); + + queue_work(shdlc->sm_wq, &shdlc->sm_work); + + wait_event(connect_wq, shdlc->connect_result != 1); + + return shdlc->connect_result; +} + +static void nfc_shdlc_disconnect(struct nfc_shdlc *shdlc) +{ + pr_debug("\n"); + + mutex_lock(&shdlc->state_mutex); + + shdlc->state = SHDLC_DISCONNECTED; + + mutex_unlock(&shdlc->state_mutex); + + queue_work(shdlc->sm_wq, &shdlc->sm_work); +} + +/* + * Receive an incoming shdlc frame. Frame has already been crc-validated. + * skb contains only LLC header and payload. + * If skb == NULL, it is a notification that the link below is dead. + */ +void nfc_shdlc_recv_frame(struct nfc_shdlc *shdlc, struct sk_buff *skb) +{ + if (skb == NULL) { + pr_err("NULL Frame -> link is dead\n"); + shdlc->hard_fault = -EREMOTEIO; + } else { + SHDLC_DUMP_SKB("incoming frame", skb); + skb_queue_tail(&shdlc->rcv_q, skb); + } + + queue_work(shdlc->sm_wq, &shdlc->sm_work); +} +EXPORT_SYMBOL(nfc_shdlc_recv_frame); + +static int nfc_shdlc_open(struct nfc_hci_dev *hdev) +{ + struct nfc_shdlc *shdlc = nfc_hci_get_clientdata(hdev); + int r; + + pr_debug("\n"); + + if (shdlc->ops->open) { + r = shdlc->ops->open(shdlc); + if (r < 0) + return r; + } + + r = nfc_shdlc_connect(shdlc); + if (r < 0 && shdlc->ops->close) + shdlc->ops->close(shdlc); + + return r; +} + +static void nfc_shdlc_close(struct nfc_hci_dev *hdev) +{ + struct nfc_shdlc *shdlc = nfc_hci_get_clientdata(hdev); + + pr_debug("\n"); + + nfc_shdlc_disconnect(shdlc); + + if (shdlc->ops->close) + shdlc->ops->close(shdlc); +} + +static int nfc_shdlc_hci_ready(struct nfc_hci_dev *hdev) +{ + struct nfc_shdlc *shdlc = nfc_hci_get_clientdata(hdev); + int r = 0; + + pr_debug("\n"); + + if (shdlc->ops->hci_ready) + r = shdlc->ops->hci_ready(shdlc); + + return r; +} + +static int nfc_shdlc_xmit(struct nfc_hci_dev *hdev, struct sk_buff *skb) +{ + struct nfc_shdlc *shdlc = nfc_hci_get_clientdata(hdev); + + SHDLC_DUMP_SKB("queuing HCP packet to shdlc", skb); + + skb_queue_tail(&shdlc->send_q, skb); + + queue_work(shdlc->sm_wq, &shdlc->sm_work); + + return 0; +} + +static int nfc_shdlc_start_poll(struct nfc_hci_dev *hdev, u32 protocols) +{ + struct nfc_shdlc *shdlc = nfc_hci_get_clientdata(hdev); + + pr_debug("\n"); + + if (shdlc->ops->start_poll) + return shdlc->ops->start_poll(shdlc, protocols); + + return 0; +} + +static int nfc_shdlc_target_from_gate(struct nfc_hci_dev *hdev, u8 gate, + struct nfc_target *target) +{ + struct nfc_shdlc *shdlc = nfc_hci_get_clientdata(hdev); + + if (shdlc->ops->target_from_gate) + return shdlc->ops->target_from_gate(shdlc, gate, target); + + return -EPERM; +} + +static int nfc_shdlc_complete_target_discovered(struct nfc_hci_dev *hdev, + u8 gate, + struct nfc_target *target) +{ + struct nfc_shdlc *shdlc = nfc_hci_get_clientdata(hdev); + + pr_debug("\n"); + + if (shdlc->ops->complete_target_discovered) + return shdlc->ops->complete_target_discovered(shdlc, gate, + target); + + return 0; +} + +static int nfc_shdlc_data_exchange(struct nfc_hci_dev *hdev, + struct nfc_target *target, + struct sk_buff *skb, + struct sk_buff **res_skb) +{ + struct nfc_shdlc *shdlc = nfc_hci_get_clientdata(hdev); + + if (shdlc->ops->data_exchange) + return shdlc->ops->data_exchange(shdlc, target, skb, res_skb); + + return -EPERM; +} + +static struct nfc_hci_ops shdlc_ops = { + .open = nfc_shdlc_open, + .close = nfc_shdlc_close, + .hci_ready = nfc_shdlc_hci_ready, + .xmit = nfc_shdlc_xmit, + .start_poll = nfc_shdlc_start_poll, + .target_from_gate = nfc_shdlc_target_from_gate, + .complete_target_discovered = nfc_shdlc_complete_target_discovered, + .data_exchange = nfc_shdlc_data_exchange, +}; + +struct nfc_shdlc *nfc_shdlc_allocate(struct nfc_shdlc_ops *ops, + struct nfc_hci_init_data *init_data, + u32 protocols, + int tx_headroom, int tx_tailroom, + int max_link_payload, const char *devname) +{ + struct nfc_shdlc *shdlc; + int r; + char name[32]; + + if (ops->xmit == NULL) + return NULL; + + shdlc = kzalloc(sizeof(struct nfc_shdlc), GFP_KERNEL); + if (shdlc == NULL) + return NULL; + + mutex_init(&shdlc->state_mutex); + shdlc->ops = ops; + shdlc->state = SHDLC_DISCONNECTED; + + init_timer(&shdlc->connect_timer); + shdlc->connect_timer.data = (unsigned long)shdlc; + shdlc->connect_timer.function = nfc_shdlc_connect_timeout; + + init_timer(&shdlc->t1_timer); + shdlc->t1_timer.data = (unsigned long)shdlc; + shdlc->t1_timer.function = nfc_shdlc_t1_timeout; + + init_timer(&shdlc->t2_timer); + shdlc->t2_timer.data = (unsigned long)shdlc; + shdlc->t2_timer.function = nfc_shdlc_t2_timeout; + + shdlc->w = SHDLC_MAX_WINDOW; + shdlc->srej_support = SHDLC_SREJ_SUPPORT; + + skb_queue_head_init(&shdlc->rcv_q); + skb_queue_head_init(&shdlc->send_q); + skb_queue_head_init(&shdlc->ack_pending_q); + + INIT_WORK(&shdlc->sm_work, nfc_shdlc_sm_work); + snprintf(name, sizeof(name), "%s_shdlc_sm_wq", devname); + shdlc->sm_wq = alloc_workqueue(name, WQ_NON_REENTRANT | WQ_UNBOUND | + WQ_MEM_RECLAIM, 1); + if (shdlc->sm_wq == NULL) + goto err_allocwq; + + shdlc->client_headroom = tx_headroom; + shdlc->client_tailroom = tx_tailroom; + + shdlc->hdev = nfc_hci_allocate_device(&shdlc_ops, init_data, protocols, + tx_headroom + SHDLC_LLC_HEAD_ROOM, + tx_tailroom + SHDLC_LLC_TAIL_ROOM, + max_link_payload); + if (shdlc->hdev == NULL) + goto err_allocdev; + + nfc_hci_set_clientdata(shdlc->hdev, shdlc); + + r = nfc_hci_register_device(shdlc->hdev); + if (r < 0) + goto err_regdev; + + return shdlc; + +err_regdev: + nfc_hci_free_device(shdlc->hdev); + +err_allocdev: + destroy_workqueue(shdlc->sm_wq); + +err_allocwq: + kfree(shdlc); + + return NULL; +} +EXPORT_SYMBOL(nfc_shdlc_allocate); + +void nfc_shdlc_free(struct nfc_shdlc *shdlc) +{ + pr_debug("\n"); + + /* TODO: Check that this cannot be called while still in use */ + + nfc_hci_unregister_device(shdlc->hdev); + nfc_hci_free_device(shdlc->hdev); + + destroy_workqueue(shdlc->sm_wq); + + skb_queue_purge(&shdlc->rcv_q); + skb_queue_purge(&shdlc->send_q); + skb_queue_purge(&shdlc->ack_pending_q); + + kfree(shdlc); +} +EXPORT_SYMBOL(nfc_shdlc_free); + +void nfc_shdlc_set_clientdata(struct nfc_shdlc *shdlc, void *clientdata) +{ + pr_debug("\n"); + + shdlc->clientdata = clientdata; +} +EXPORT_SYMBOL(nfc_shdlc_set_clientdata); + +void *nfc_shdlc_get_clientdata(struct nfc_shdlc *shdlc) +{ + return shdlc->clientdata; +} +EXPORT_SYMBOL(nfc_shdlc_get_clientdata); + +struct nfc_hci_dev *nfc_shdlc_get_hci_dev(struct nfc_shdlc *shdlc) +{ + return shdlc->hdev; +} +EXPORT_SYMBOL(nfc_shdlc_get_hci_dev); |