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NFC: SHDLC implementation

Browse Source 
Most NFC HCI chipsets actually use a simplified HDLC link layer to
carry HCI payloads.
This implementation registers itself as an HCI device on behalf of the
NFC driver.

Signed-off-by: Eric Lapuyade <eric.lapuyade@intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
tirimbino
Eric Lapuyade 13 years ago committed by John W. Linville
parent 8b8d2e08bf
commit eb738fe535
4 changed files with 1058 additions and 0 deletions
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
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  1. 104
      include/net/nfc/shdlc.h
  2. 8
      net/nfc/hci/Kconfig
  3. 1
      net/nfc/hci/Makefile
  4. 945
      net/nfc/hci/shdlc.c

104
include/net/nfc/shdlc.h
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@ -0,0 +1,104 @@
/*
* 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.
*/
#ifndef __NFC_SHDLC_H
#define __NFC_SHDLC_H
struct nfc_shdlc;
struct nfc_shdlc_ops {
int (*open) (struct nfc_shdlc *shdlc);
void (*close) (struct nfc_shdlc *shdlc);
int (*hci_ready) (struct nfc_shdlc *shdlc);
int (*xmit) (struct nfc_shdlc *shdlc, struct sk_buff *skb);
int (*start_poll) (struct nfc_shdlc *shdlc, u32 protocols);
int (*target_from_gate) (struct nfc_shdlc *shdlc, u8 gate,
struct nfc_target *target);
int (*complete_target_discovered) (struct nfc_shdlc *shdlc, u8 gate,
struct nfc_target *target);
int (*data_exchange) (struct nfc_shdlc *shdlc,
struct nfc_target *target,
struct sk_buff *skb, struct sk_buff **res_skb);
};
enum shdlc_state {
SHDLC_DISCONNECTED = 0,
SHDLC_CONNECTING = 1,
SHDLC_NEGOCIATING = 2,
SHDLC_CONNECTED = 3
};
struct nfc_shdlc {
struct mutex state_mutex;
enum shdlc_state state;
int hard_fault;
struct nfc_hci_dev *hdev;
wait_queue_head_t *connect_wq;
int connect_tries;
int connect_result;
struct timer_list connect_timer;/* aka T3 in spec 10.6.1 */
u8 w; /* window size */
bool srej_support;
struct timer_list t1_timer; /* send ack timeout */
bool t1_active;
struct timer_list t2_timer; /* guard/retransmit timeout */
bool t2_active;
int ns; /* next seq num for send */
int nr; /* next expected seq num for receive */
int dnr; /* oldest sent unacked seq num */
struct sk_buff_head rcv_q;
struct sk_buff_head send_q;
bool rnr; /* other side is not ready to receive */
struct sk_buff_head ack_pending_q;
struct workqueue_struct *sm_wq;
struct work_struct sm_work;
struct nfc_shdlc_ops *ops;
int client_headroom;
int client_tailroom;
void *clientdata;
};
void nfc_shdlc_recv_frame(struct nfc_shdlc *shdlc, struct sk_buff *skb);
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);
void nfc_shdlc_free(struct nfc_shdlc *shdlc);
void nfc_shdlc_set_clientdata(struct nfc_shdlc *shdlc, void *clientdata);
void *nfc_shdlc_get_clientdata(struct nfc_shdlc *shdlc);
struct nfc_hci_dev *nfc_shdlc_get_hci_dev(struct nfc_shdlc *shdlc);
#endif /* __NFC_SHDLC_H */

8
net/nfc/hci/Kconfig
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@ -6,3 +6,11 @@ config NFC_HCI
Say Y here if you want to build support for a kernel NFC HCI
implementation. This is mostly needed for devices that only process
HCI frames, like for example the NXP pn544.
config NFC_SHDLC
depends on NFC_HCI
bool "SHDLC link layer for HCI based NFC drivers"
default n
---help---
Say yes if you use an NFC HCI driver that requires SHDLC link layer.
If unsure, say N here.

1
net/nfc/hci/Makefile
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@ -5,3 +5,4 @@
obj-$(CONFIG_NFC_HCI) += hci.o
hci-y := core.o hcp.o command.o
hci-$(CONFIG_NFC_SHDLC) += shdlc.o

945
net/nfc/hci/shdlc.c
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@ -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);
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