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NFC: SHDLC implementation
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>
This commit is contained in:
Eric Lapuyade
John W. Linville
parent
8b8d2e08bf
commit
eb738fe535
104
include/net/nfc/shdlc.h
Normal file
104
include/net/nfc/shdlc.h
Normal file
@ -0,0 +1,104 @@
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/*
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* Copyright (C) 2012 Intel Corporation. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the
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* Free Software Foundation, Inc.,
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* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#ifndef __NFC_SHDLC_H
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#define __NFC_SHDLC_H
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struct nfc_shdlc;
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struct nfc_shdlc_ops {
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int (*open) (struct nfc_shdlc *shdlc);
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void (*close) (struct nfc_shdlc *shdlc);
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int (*hci_ready) (struct nfc_shdlc *shdlc);
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int (*xmit) (struct nfc_shdlc *shdlc, struct sk_buff *skb);
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int (*start_poll) (struct nfc_shdlc *shdlc, u32 protocols);
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int (*target_from_gate) (struct nfc_shdlc *shdlc, u8 gate,
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struct nfc_target *target);
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int (*complete_target_discovered) (struct nfc_shdlc *shdlc, u8 gate,
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struct nfc_target *target);
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int (*data_exchange) (struct nfc_shdlc *shdlc,
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struct nfc_target *target,
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struct sk_buff *skb, struct sk_buff **res_skb);
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};
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enum shdlc_state {
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SHDLC_DISCONNECTED = 0,
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SHDLC_CONNECTING = 1,
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SHDLC_NEGOCIATING = 2,
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SHDLC_CONNECTED = 3
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};
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struct nfc_shdlc {
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struct mutex state_mutex;
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enum shdlc_state state;
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int hard_fault;
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struct nfc_hci_dev *hdev;
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wait_queue_head_t *connect_wq;
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int connect_tries;
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int connect_result;
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struct timer_list connect_timer;/* aka T3 in spec 10.6.1 */
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u8 w; /* window size */
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bool srej_support;
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struct timer_list t1_timer; /* send ack timeout */
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bool t1_active;
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struct timer_list t2_timer; /* guard/retransmit timeout */
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bool t2_active;
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int ns; /* next seq num for send */
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int nr; /* next expected seq num for receive */
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int dnr; /* oldest sent unacked seq num */
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struct sk_buff_head rcv_q;
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struct sk_buff_head send_q;
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bool rnr; /* other side is not ready to receive */
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struct sk_buff_head ack_pending_q;
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struct workqueue_struct *sm_wq;
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struct work_struct sm_work;
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struct nfc_shdlc_ops *ops;
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int client_headroom;
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int client_tailroom;
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void *clientdata;
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};
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void nfc_shdlc_recv_frame(struct nfc_shdlc *shdlc, struct sk_buff *skb);
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struct nfc_shdlc *nfc_shdlc_allocate(struct nfc_shdlc_ops *ops,
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struct nfc_hci_init_data *init_data,
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u32 protocols,
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int tx_headroom, int tx_tailroom,
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int max_link_payload, const char *devname);
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void nfc_shdlc_free(struct nfc_shdlc *shdlc);
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void nfc_shdlc_set_clientdata(struct nfc_shdlc *shdlc, void *clientdata);
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void *nfc_shdlc_get_clientdata(struct nfc_shdlc *shdlc);
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struct nfc_hci_dev *nfc_shdlc_get_hci_dev(struct nfc_shdlc *shdlc);
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#endif /* __NFC_SHDLC_H */
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@ -6,3 +6,11 @@ config NFC_HCI
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Say Y here if you want to build support for a kernel NFC HCI
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implementation. This is mostly needed for devices that only process
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HCI frames, like for example the NXP pn544.
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config NFC_SHDLC
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depends on NFC_HCI
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bool "SHDLC link layer for HCI based NFC drivers"
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default n
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---help---
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Say yes if you use an NFC HCI driver that requires SHDLC link layer.
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If unsure, say N here.
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@ -5,3 +5,4 @@
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obj-$(CONFIG_NFC_HCI) += hci.o
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hci-y := core.o hcp.o command.o
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hci-$(CONFIG_NFC_SHDLC) += shdlc.o
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945
net/nfc/hci/shdlc.c
Normal file
945
net/nfc/hci/shdlc.c
Normal file
@ -0,0 +1,945 @@
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/*
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* Copyright (C) 2012 Intel Corporation. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the
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* Free Software Foundation, Inc.,
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* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#define pr_fmt(fmt) "shdlc: %s: " fmt, __func__
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#include <linux/sched.h>
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#include <linux/export.h>
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#include <linux/wait.h>
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#include <linux/crc-ccitt.h>
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#include <linux/slab.h>
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#include <linux/skbuff.h>
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#include <net/nfc/hci.h>
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#include <net/nfc/shdlc.h>
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#define SHDLC_LLC_HEAD_ROOM 2
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#define SHDLC_LLC_TAIL_ROOM 2
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#define SHDLC_MAX_WINDOW 4
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#define SHDLC_SREJ_SUPPORT false
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#define SHDLC_CONTROL_HEAD_MASK 0xe0
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#define SHDLC_CONTROL_HEAD_I 0x80
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#define SHDLC_CONTROL_HEAD_I2 0xa0
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#define SHDLC_CONTROL_HEAD_S 0xc0
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#define SHDLC_CONTROL_HEAD_U 0xe0
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#define SHDLC_CONTROL_NS_MASK 0x38
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#define SHDLC_CONTROL_NR_MASK 0x07
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#define SHDLC_CONTROL_TYPE_MASK 0x18
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#define SHDLC_CONTROL_M_MASK 0x1f
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enum sframe_type {
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S_FRAME_RR = 0x00,
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S_FRAME_REJ = 0x01,
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S_FRAME_RNR = 0x02,
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S_FRAME_SREJ = 0x03
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};
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enum uframe_modifier {
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U_FRAME_UA = 0x06,
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U_FRAME_RSET = 0x19
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};
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#define SHDLC_CONNECT_VALUE_MS 5
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#define SHDLC_T1_VALUE_MS(w) ((5 * w) / 4)
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#define SHDLC_T2_VALUE_MS 300
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#define SHDLC_DUMP_SKB(info, skb) \
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do { \
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pr_debug("%s:\n", info); \
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print_hex_dump(KERN_DEBUG, "shdlc: ", DUMP_PREFIX_OFFSET, \
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16, 1, skb->data, skb->len, 0); \
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} while (0)
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/* checks x < y <= z modulo 8 */
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static bool nfc_shdlc_x_lt_y_lteq_z(int x, int y, int z)
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{
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if (x < z)
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return ((x < y) && (y <= z)) ? true : false;
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else
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return ((y > x) || (y <= z)) ? true : false;
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}
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/* checks x <= y < z modulo 8 */
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static bool nfc_shdlc_x_lteq_y_lt_z(int x, int y, int z)
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{
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if (x <= z)
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return ((x <= y) && (y < z)) ? true : false;
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else /* x > z -> z+8 > x */
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return ((y >= x) || (y < z)) ? true : false;
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}
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static struct sk_buff *nfc_shdlc_alloc_skb(struct nfc_shdlc *shdlc,
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int payload_len)
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{
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struct sk_buff *skb;
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skb = alloc_skb(shdlc->client_headroom + SHDLC_LLC_HEAD_ROOM +
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shdlc->client_tailroom + SHDLC_LLC_TAIL_ROOM +
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payload_len, GFP_KERNEL);
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if (skb)
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skb_reserve(skb, shdlc->client_headroom + SHDLC_LLC_HEAD_ROOM);
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return skb;
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}
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static void nfc_shdlc_add_len_crc(struct sk_buff *skb)
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{
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u16 crc;
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int len;
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len = skb->len + 2;
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*skb_push(skb, 1) = len;
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crc = crc_ccitt(0xffff, skb->data, skb->len);
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crc = ~crc;
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*skb_put(skb, 1) = crc & 0xff;
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*skb_put(skb, 1) = crc >> 8;
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}
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/* immediately sends an S frame. */
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static int nfc_shdlc_send_s_frame(struct nfc_shdlc *shdlc,
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enum sframe_type sframe_type, int nr)
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{
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int r;
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struct sk_buff *skb;
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pr_debug("sframe_type=%d nr=%d\n", sframe_type, nr);
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skb = nfc_shdlc_alloc_skb(shdlc, 0);
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if (skb == NULL)
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return -ENOMEM;
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*skb_push(skb, 1) = SHDLC_CONTROL_HEAD_S | (sframe_type << 3) | nr;
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nfc_shdlc_add_len_crc(skb);
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r = shdlc->ops->xmit(shdlc, skb);
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kfree_skb(skb);
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return r;
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}
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/* immediately sends an U frame. skb may contain optional payload */
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static int nfc_shdlc_send_u_frame(struct nfc_shdlc *shdlc,
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struct sk_buff *skb,
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enum uframe_modifier uframe_modifier)
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{
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int r;
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pr_debug("uframe_modifier=%d\n", uframe_modifier);
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*skb_push(skb, 1) = SHDLC_CONTROL_HEAD_U | uframe_modifier;
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nfc_shdlc_add_len_crc(skb);
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r = shdlc->ops->xmit(shdlc, skb);
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kfree_skb(skb);
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return r;
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}
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/*
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* Free ack_pending frames until y_nr - 1, and reset t2 according to
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* the remaining oldest ack_pending frame sent time
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*/
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static void nfc_shdlc_reset_t2(struct nfc_shdlc *shdlc, int y_nr)
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{
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struct sk_buff *skb;
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int dnr = shdlc->dnr; /* MUST initially be < y_nr */
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pr_debug("release ack pending up to frame %d excluded\n", y_nr);
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while (dnr != y_nr) {
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pr_debug("release ack pending frame %d\n", dnr);
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skb = skb_dequeue(&shdlc->ack_pending_q);
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kfree_skb(skb);
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dnr = (dnr + 1) % 8;
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}
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if (skb_queue_empty(&shdlc->ack_pending_q)) {
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if (shdlc->t2_active) {
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del_timer_sync(&shdlc->t2_timer);
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shdlc->t2_active = false;
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pr_debug
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("All sent frames acked. Stopped T2(retransmit)\n");
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}
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} else {
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skb = skb_peek(&shdlc->ack_pending_q);
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mod_timer(&shdlc->t2_timer, *(unsigned long *)skb->cb +
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msecs_to_jiffies(SHDLC_T2_VALUE_MS));
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shdlc->t2_active = true;
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pr_debug
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("Start T2(retransmit) for remaining unacked sent frames\n");
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}
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}
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/*
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* Receive validated frames from lower layer. skb contains HCI payload only.
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* Handle according to algorithm at spec:10.8.2
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*/
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static void nfc_shdlc_rcv_i_frame(struct nfc_shdlc *shdlc,
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struct sk_buff *skb, int ns, int nr)
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{
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int x_ns = ns;
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int y_nr = nr;
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pr_debug("recvd I-frame %d, remote waiting frame %d\n", ns, nr);
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if (shdlc->state != SHDLC_CONNECTED)
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goto exit;
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if (x_ns != shdlc->nr) {
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nfc_shdlc_send_s_frame(shdlc, S_FRAME_REJ, shdlc->nr);
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goto exit;
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}
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if (shdlc->t1_active == false) {
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shdlc->t1_active = true;
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mod_timer(&shdlc->t1_timer,
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msecs_to_jiffies(SHDLC_T1_VALUE_MS(shdlc->w)));
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pr_debug("(re)Start T1(send ack)\n");
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}
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if (skb->len) {
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nfc_hci_recv_frame(shdlc->hdev, skb);
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skb = NULL;
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}
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shdlc->nr = (shdlc->nr + 1) % 8;
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if (nfc_shdlc_x_lt_y_lteq_z(shdlc->dnr, y_nr, shdlc->ns)) {
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nfc_shdlc_reset_t2(shdlc, y_nr);
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shdlc->dnr = y_nr;
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}
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exit:
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if (skb)
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kfree_skb(skb);
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}
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static void nfc_shdlc_rcv_ack(struct nfc_shdlc *shdlc, int y_nr)
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{
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pr_debug("remote acked up to frame %d excluded\n", y_nr);
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if (nfc_shdlc_x_lt_y_lteq_z(shdlc->dnr, y_nr, shdlc->ns)) {
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nfc_shdlc_reset_t2(shdlc, y_nr);
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shdlc->dnr = y_nr;
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}
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}
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static void nfc_shdlc_requeue_ack_pending(struct nfc_shdlc *shdlc)
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{
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struct sk_buff *skb;
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pr_debug("ns reset to %d\n", shdlc->dnr);
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while ((skb = skb_dequeue_tail(&shdlc->ack_pending_q))) {
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skb_pull(skb, 2); /* remove len+control */
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skb_trim(skb, skb->len - 2); /* remove crc */
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skb_queue_head(&shdlc->send_q, skb);
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}
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shdlc->ns = shdlc->dnr;
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}
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static void nfc_shdlc_rcv_rej(struct nfc_shdlc *shdlc, int y_nr)
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{
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struct sk_buff *skb;
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pr_debug("remote asks retransmition from frame %d\n", y_nr);
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if (nfc_shdlc_x_lteq_y_lt_z(shdlc->dnr, y_nr, shdlc->ns)) {
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if (shdlc->t2_active) {
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del_timer_sync(&shdlc->t2_timer);
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shdlc->t2_active = false;
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pr_debug("Stopped T2(retransmit)\n");
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}
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if (shdlc->dnr != y_nr) {
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while ((shdlc->dnr = ((shdlc->dnr + 1) % 8)) != y_nr) {
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skb = skb_dequeue(&shdlc->ack_pending_q);
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kfree_skb(skb);
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}
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}
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nfc_shdlc_requeue_ack_pending(shdlc);
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}
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}
|
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/* See spec RR:10.8.3 REJ:10.8.4 */
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static void nfc_shdlc_rcv_s_frame(struct nfc_shdlc *shdlc,
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enum sframe_type s_frame_type, int nr)
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{
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struct sk_buff *skb;
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|
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if (shdlc->state != SHDLC_CONNECTED)
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return;
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switch (s_frame_type) {
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case S_FRAME_RR:
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nfc_shdlc_rcv_ack(shdlc, nr);
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if (shdlc->rnr == true) { /* see SHDLC 10.7.7 */
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shdlc->rnr = false;
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if (shdlc->send_q.qlen == 0) {
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skb = nfc_shdlc_alloc_skb(shdlc, 0);
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if (skb)
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skb_queue_tail(&shdlc->send_q, skb);
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}
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}
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break;
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case S_FRAME_REJ:
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nfc_shdlc_rcv_rej(shdlc, nr);
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||||
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);
|
||||
Loading…
Reference in New Issue
Block a user