/* * Shared Transport Line discipline driver Core * This hooks up ST KIM driver and ST LL driver * Copyright (C) 2009-2010 Texas Instruments * Author: Pavan Savoy * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * * 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) "(stc): " fmt #include #include #include #include #include #include #include /* function pointer pointing to either, * st_kim_recv during registration to receive fw download responses * st_int_recv after registration to receive proto stack responses */ void (*st_recv) (void*, const unsigned char*, long); /********************************************************************/ static void add_channel_to_table(struct st_data_s *st_gdata, struct st_proto_s *new_proto) { pr_info("%s: id %d\n", __func__, new_proto->chnl_id); /* list now has the channel id as index itself */ st_gdata->list[new_proto->chnl_id] = new_proto; } static void remove_channel_from_table(struct st_data_s *st_gdata, struct st_proto_s *proto) { pr_info("%s: id %d\n", __func__, proto->chnl_id); st_gdata->list[proto->chnl_id] = NULL; } /* can be called in from * -- KIM (during fw download) * -- ST Core (during st_write) * * This is the internal write function - a wrapper * to tty->ops->write */ int st_int_write(struct st_data_s *st_gdata, const unsigned char *data, int count) { struct tty_struct *tty; if (unlikely(st_gdata == NULL || st_gdata->tty == NULL)) { pr_err("tty unavailable to perform write"); return -EINVAL; } tty = st_gdata->tty; #ifdef VERBOSE print_hex_dump(KERN_DEBUG, "ops->write(tty, data, count); } /* * push the skb received to relevant * protocol stacks */ void st_send_frame(unsigned char chnl_id, struct st_data_s *st_gdata) { pr_debug(" %s(prot:%d) ", __func__, chnl_id); if (unlikely (st_gdata == NULL || st_gdata->rx_skb == NULL || st_gdata->list[chnl_id] == NULL)) { pr_err("chnl_id %d not registered, no data to send?", chnl_id); kfree_skb(st_gdata->rx_skb); return; } /* this cannot fail * this shouldn't take long * - should be just skb_queue_tail for the * protocol stack driver */ if (likely(st_gdata->list[chnl_id]->recv != NULL)) { if (unlikely (st_gdata->list[chnl_id]->recv (st_gdata->list[chnl_id]->priv_data, st_gdata->rx_skb) != 0)) { pr_err(" proto stack %d's ->recv failed", chnl_id); kfree_skb(st_gdata->rx_skb); return; } } else { pr_err(" proto stack %d's ->recv null", chnl_id); kfree_skb(st_gdata->rx_skb); } return; } /** * st_reg_complete - * to call registration complete callbacks * of all protocol stack drivers */ void st_reg_complete(struct st_data_s *st_gdata, char err) { unsigned char i = 0; pr_info(" %s ", __func__); for (i = 0; i < ST_MAX_CHANNELS; i++) { if (likely(st_gdata != NULL && st_gdata->list[i] != NULL && st_gdata->list[i]->reg_complete_cb != NULL)) { st_gdata->list[i]->reg_complete_cb (st_gdata->list[i]->priv_data, err); pr_info("protocol %d's cb sent %d\n", i, err); if (err) { /* cleanup registered protocol */ st_gdata->protos_registered--; st_gdata->list[i] = NULL; } } } } static inline int st_check_data_len(struct st_data_s *st_gdata, unsigned char chnl_id, int len) { int room = skb_tailroom(st_gdata->rx_skb); pr_debug("len %d room %d", len, room); if (!len) { /* Received packet has only packet header and * has zero length payload. So, ask ST CORE to * forward the packet to protocol driver (BT/FM/GPS) */ st_send_frame(chnl_id, st_gdata); } else if (len > room) { /* Received packet's payload length is larger. * We can't accommodate it in created skb. */ pr_err("Data length is too large len %d room %d", len, room); kfree_skb(st_gdata->rx_skb); } else { /* Packet header has non-zero payload length and * we have enough space in created skb. Lets read * payload data */ st_gdata->rx_state = ST_W4_DATA; st_gdata->rx_count = len; return len; } /* Change ST state to continue to process next * packet */ st_gdata->rx_state = ST_W4_PACKET_TYPE; st_gdata->rx_skb = NULL; st_gdata->rx_count = 0; st_gdata->rx_chnl = 0; return 0; } /** * st_wakeup_ack - internal function for action when wake-up ack * received */ static inline void st_wakeup_ack(struct st_data_s *st_gdata, unsigned char cmd) { struct sk_buff *waiting_skb; unsigned long flags = 0; spin_lock_irqsave(&st_gdata->lock, flags); /* de-Q from waitQ and Q in txQ now that the * chip is awake */ while ((waiting_skb = skb_dequeue(&st_gdata->tx_waitq))) skb_queue_tail(&st_gdata->txq, waiting_skb); /* state forwarded to ST LL */ st_ll_sleep_state(st_gdata, (unsigned long)cmd); spin_unlock_irqrestore(&st_gdata->lock, flags); /* wake up to send the recently copied skbs from waitQ */ st_tx_wakeup(st_gdata); } /** * st_int_recv - ST's internal receive function. * Decodes received RAW data and forwards to corresponding * client drivers (Bluetooth,FM,GPS..etc). * This can receive various types of packets, * HCI-Events, ACL, SCO, 4 types of HCI-LL PM packets * CH-8 packets from FM, CH-9 packets from GPS cores. */ void st_int_recv(void *disc_data, const unsigned char *data, long count) { char *ptr; struct st_proto_s *proto; unsigned short payload_len = 0; int len = 0, type = 0; unsigned char *plen; struct st_data_s *st_gdata = (struct st_data_s *)disc_data; ptr = (char *)data; /* tty_receive sent null ? */ if (unlikely(ptr == NULL) || (st_gdata == NULL)) { pr_err(" received null from TTY "); return; } pr_debug("count %ld rx_state %ld" "rx_count %ld", count, st_gdata->rx_state, st_gdata->rx_count); /* Decode received bytes here */ while (count) { if (st_gdata->rx_count) { len = min_t(unsigned int, st_gdata->rx_count, count); memcpy(skb_put(st_gdata->rx_skb, len), ptr, len); st_gdata->rx_count -= len; count -= len; ptr += len; if (st_gdata->rx_count) continue; /* Check ST RX state machine , where are we? */ switch (st_gdata->rx_state) { /* Waiting for complete packet ? */ case ST_W4_DATA: pr_debug("Complete pkt received"); /* Ask ST CORE to forward * the packet to protocol driver */ st_send_frame(st_gdata->rx_chnl, st_gdata); st_gdata->rx_state = ST_W4_PACKET_TYPE; st_gdata->rx_skb = NULL; continue; /* parse the header to know details */ case ST_W4_HEADER: proto = st_gdata->list[st_gdata->rx_chnl]; plen = &st_gdata->rx_skb->data [proto->offset_len_in_hdr]; pr_debug("plen pointing to %x\n", *plen); if (proto->len_size == 1)/* 1 byte len field */ payload_len = *(unsigned char *)plen; else if (proto->len_size == 2) payload_len = __le16_to_cpu(*(unsigned short *)plen); else pr_info("%s: invalid length " "for id %d\n", __func__, proto->chnl_id); st_check_data_len(st_gdata, proto->chnl_id, payload_len); pr_debug("off %d, pay len %d\n", proto->offset_len_in_hdr, payload_len); continue; } /* end of switch rx_state */ } /* end of if rx_count */ /* Check first byte of packet and identify module * owner (BT/FM/GPS) */ switch (*ptr) { case LL_SLEEP_IND: case LL_SLEEP_ACK: case LL_WAKE_UP_IND: pr_debug("PM packet"); /* this takes appropriate action based on * sleep state received -- */ st_ll_sleep_state(st_gdata, *ptr); ptr++; count--; continue; case LL_WAKE_UP_ACK: pr_debug("PM packet"); /* wake up ack received */ st_wakeup_ack(st_gdata, *ptr); ptr++; count--; continue; /* Unknow packet? */ default: type = *ptr; st_gdata->rx_skb = alloc_skb( st_gdata->list[type]->max_frame_size, GFP_ATOMIC); skb_reserve(st_gdata->rx_skb, st_gdata->list[type]->reserve); /* next 2 required for BT only */ st_gdata->rx_skb->cb[0] = type; /*pkt_type*/ st_gdata->rx_skb->cb[1] = 0; /*incoming*/ st_gdata->rx_chnl = *ptr; st_gdata->rx_state = ST_W4_HEADER; st_gdata->rx_count = st_gdata->list[type]->hdr_len; pr_debug("rx_count %ld\n", st_gdata->rx_count); }; ptr++; count--; } pr_debug("done %s", __func__); return; } /** * st_int_dequeue - internal de-Q function. * If the previous data set was not written * completely, return that skb which has the pending data. * In normal cases, return top of txq. */ struct sk_buff *st_int_dequeue(struct st_data_s *st_gdata) { struct sk_buff *returning_skb; pr_debug("%s", __func__); if (st_gdata->tx_skb != NULL) { returning_skb = st_gdata->tx_skb; st_gdata->tx_skb = NULL; return returning_skb; } return skb_dequeue(&st_gdata->txq); } /** * st_int_enqueue - internal Q-ing function. * Will either Q the skb to txq or the tx_waitq * depending on the ST LL state. * If the chip is asleep, then Q it onto waitq and * wakeup the chip. * txq and waitq needs protection since the other contexts * may be sending data, waking up chip. */ void st_int_enqueue(struct st_data_s *st_gdata, struct sk_buff *skb) { unsigned long flags = 0; pr_debug("%s", __func__); spin_lock_irqsave(&st_gdata->lock, flags); switch (st_ll_getstate(st_gdata)) { case ST_LL_AWAKE: pr_debug("ST LL is AWAKE, sending normally"); skb_queue_tail(&st_gdata->txq, skb); break; case ST_LL_ASLEEP_TO_AWAKE: skb_queue_tail(&st_gdata->tx_waitq, skb); break; case ST_LL_AWAKE_TO_ASLEEP: pr_err("ST LL is illegal state(%ld)," "purging received skb.", st_ll_getstate(st_gdata)); kfree_skb(skb); break; case ST_LL_ASLEEP: skb_queue_tail(&st_gdata->tx_waitq, skb); st_ll_wakeup(st_gdata); break; default: pr_err("ST LL is illegal state(%ld)," "purging received skb.", st_ll_getstate(st_gdata)); kfree_skb(skb); break; } spin_unlock_irqrestore(&st_gdata->lock, flags); pr_debug("done %s", __func__); return; } /* * internal wakeup function * called from either * - TTY layer when write's finished * - st_write (in context of the protocol stack) */ void st_tx_wakeup(struct st_data_s *st_data) { struct sk_buff *skb; unsigned long flags; /* for irq save flags */ pr_debug("%s", __func__); /* check for sending & set flag sending here */ if (test_and_set_bit(ST_TX_SENDING, &st_data->tx_state)) { pr_debug("ST already sending"); /* keep sending */ set_bit(ST_TX_WAKEUP, &st_data->tx_state); return; /* TX_WAKEUP will be checked in another * context */ } do { /* come back if st_tx_wakeup is set */ /* woke-up to write */ clear_bit(ST_TX_WAKEUP, &st_data->tx_state); while ((skb = st_int_dequeue(st_data))) { int len; spin_lock_irqsave(&st_data->lock, flags); /* enable wake-up from TTY */ set_bit(TTY_DO_WRITE_WAKEUP, &st_data->tty->flags); len = st_int_write(st_data, skb->data, skb->len); skb_pull(skb, len); /* if skb->len = len as expected, skb->len=0 */ if (skb->len) { /* would be the next skb to be sent */ st_data->tx_skb = skb; spin_unlock_irqrestore(&st_data->lock, flags); break; } kfree_skb(skb); spin_unlock_irqrestore(&st_data->lock, flags); } /* if wake-up is set in another context- restart sending */ } while (test_bit(ST_TX_WAKEUP, &st_data->tx_state)); /* clear flag sending */ clear_bit(ST_TX_SENDING, &st_data->tx_state); } /********************************************************************/ /* functions called from ST KIM */ void kim_st_list_protocols(struct st_data_s *st_gdata, void *buf) { seq_printf(buf, "[%d]\nBT=%c\nFM=%c\nGPS=%c\n", st_gdata->protos_registered, st_gdata->list[ST_BT] != NULL ? 'R' : 'U', st_gdata->list[ST_FM] != NULL ? 'R' : 'U', st_gdata->list[ST_GPS] != NULL ? 'R' : 'U'); } /********************************************************************/ /* * functions called from protocol stack drivers * to be EXPORT-ed */ long st_register(struct st_proto_s *new_proto) { struct st_data_s *st_gdata; long err = 0; unsigned long flags = 0; st_kim_ref(&st_gdata, 0); pr_info("%s(%d) ", __func__, new_proto->chnl_id); if (st_gdata == NULL || new_proto == NULL || new_proto->recv == NULL || new_proto->reg_complete_cb == NULL) { pr_err("gdata/new_proto/recv or reg_complete_cb not ready"); return -EINVAL; } if (new_proto->chnl_id >= ST_MAX_CHANNELS) { pr_err("chnl_id %d not supported", new_proto->chnl_id); return -EPROTONOSUPPORT; } if (st_gdata->list[new_proto->chnl_id] != NULL) { pr_err("chnl_id %d already registered", new_proto->chnl_id); return -EALREADY; } /* can be from process context only */ spin_lock_irqsave(&st_gdata->lock, flags); if (test_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state)) { pr_info(" ST_REG_IN_PROGRESS:%d ", new_proto->chnl_id); /* fw download in progress */ st_kim_chip_toggle(new_proto->chnl_id, KIM_GPIO_ACTIVE); add_channel_to_table(st_gdata, new_proto); st_gdata->protos_registered++; new_proto->write = st_write; set_bit(ST_REG_PENDING, &st_gdata->st_state); spin_unlock_irqrestore(&st_gdata->lock, flags); return -EINPROGRESS; } else if (st_gdata->protos_registered == ST_EMPTY) { pr_info(" chnl_id list empty :%d ", new_proto->chnl_id); set_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state); st_recv = st_kim_recv; /* release lock previously held - re-locked below */ spin_unlock_irqrestore(&st_gdata->lock, flags); /* enable the ST LL - to set default chip state */ st_ll_enable(st_gdata); /* this may take a while to complete * since it involves BT fw download */ err = st_kim_start(st_gdata->kim_data); if (err != 0) { clear_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state); if ((st_gdata->protos_registered != ST_EMPTY) && (test_bit(ST_REG_PENDING, &st_gdata->st_state))) { pr_err(" KIM failure complete callback "); st_reg_complete(st_gdata, err); } return -EINVAL; } /* the chnl_id might require other gpios to be toggled */ st_kim_chip_toggle(new_proto->chnl_id, KIM_GPIO_ACTIVE); clear_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state); st_recv = st_int_recv; /* this is where all pending registration * are signalled to be complete by calling callback functions */ if ((st_gdata->protos_registered != ST_EMPTY) && (test_bit(ST_REG_PENDING, &st_gdata->st_state))) { pr_debug(" call reg complete callback "); st_reg_complete(st_gdata, 0); } clear_bit(ST_REG_PENDING, &st_gdata->st_state); /* check for already registered once more, * since the above check is old */ if (st_gdata->list[new_proto->chnl_id] != NULL) { pr_err(" proto %d already registered ", new_proto->chnl_id); return -EALREADY; } spin_lock_irqsave(&st_gdata->lock, flags); add_channel_to_table(st_gdata, new_proto); st_gdata->protos_registered++; new_proto->write = st_write; spin_unlock_irqrestore(&st_gdata->lock, flags); return err; } /* if fw is already downloaded & new stack registers protocol */ else { add_channel_to_table(st_gdata, new_proto); st_gdata->protos_registered++; new_proto->write = st_write; /* lock already held before entering else */ spin_unlock_irqrestore(&st_gdata->lock, flags); return err; } pr_debug("done %s(%d) ", __func__, new_proto->chnl_id); } EXPORT_SYMBOL_GPL(st_register); /* to unregister a protocol - * to be called from protocol stack driver */ long st_unregister(struct st_proto_s *proto) { long err = 0; unsigned long flags = 0; struct st_data_s *st_gdata; pr_debug("%s: %d ", __func__, proto->chnl_id); st_kim_ref(&st_gdata, 0); if (proto->chnl_id >= ST_MAX_CHANNELS) { pr_err(" chnl_id %d not supported", proto->chnl_id); return -EPROTONOSUPPORT; } spin_lock_irqsave(&st_gdata->lock, flags); if (st_gdata->list[proto->chnl_id] == NULL) { pr_err(" chnl_id %d not registered", proto->chnl_id); spin_unlock_irqrestore(&st_gdata->lock, flags); return -EPROTONOSUPPORT; } st_gdata->protos_registered--; remove_channel_from_table(st_gdata, proto); /* kim ignores BT in the below function * and handles the rest, BT is toggled * only in kim_start and kim_stop */ st_kim_chip_toggle(proto->chnl_id, KIM_GPIO_INACTIVE); spin_unlock_irqrestore(&st_gdata->lock, flags); if ((st_gdata->protos_registered == ST_EMPTY) && (!test_bit(ST_REG_PENDING, &st_gdata->st_state))) { pr_info(" all chnl_ids unregistered "); /* stop traffic on tty */ if (st_gdata->tty) { tty_ldisc_flush(st_gdata->tty); stop_tty(st_gdata->tty); } /* all chnl_ids now unregistered */ st_kim_stop(st_gdata->kim_data); /* disable ST LL */ st_ll_disable(st_gdata); } return err; } /* * called in protocol stack drivers * via the write function pointer */ long st_write(struct sk_buff *skb) { struct st_data_s *st_gdata; #ifdef DEBUG unsigned char chnl_id = ST_MAX_CHANNELS; #endif long len; st_kim_ref(&st_gdata, 0); if (unlikely(skb == NULL || st_gdata == NULL || st_gdata->tty == NULL)) { pr_err("data/tty unavailable to perform write"); return -EINVAL; } #ifdef DEBUG /* open-up skb to read the 1st byte */ chnl_id = skb->data[0]; if (unlikely(st_gdata->list[chnl_id] == NULL)) { pr_err(" chnl_id %d not registered, and writing? ", chnl_id); return -EINVAL; } #endif pr_debug("%d to be written", skb->len); len = skb->len; /* st_ll to decide where to enqueue the skb */ st_int_enqueue(st_gdata, skb); /* wake up */ st_tx_wakeup(st_gdata); /* return number of bytes written */ return len; } /* for protocols making use of shared transport */ EXPORT_SYMBOL_GPL(st_unregister); /********************************************************************/ /* * functions called from TTY layer */ static int st_tty_open(struct tty_struct *tty) { int err = 0; struct st_data_s *st_gdata; pr_info("%s ", __func__); st_kim_ref(&st_gdata, 0); st_gdata->tty = tty; tty->disc_data = st_gdata; /* don't do an wakeup for now */ clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); /* mem already allocated */ tty->receive_room = 65536; /* Flush any pending characters in the driver and discipline. */ tty_ldisc_flush(tty); tty_driver_flush_buffer(tty); /* * signal to UIM via KIM that - * installation of N_TI_WL ldisc is complete */ st_kim_complete(st_gdata->kim_data); pr_debug("done %s", __func__); return err; } static void st_tty_close(struct tty_struct *tty) { unsigned char i = ST_MAX_CHANNELS; unsigned long flags = 0; struct st_data_s *st_gdata = tty->disc_data; pr_info("%s ", __func__); /* TODO: * if a protocol has been registered & line discipline * un-installed for some reason - what should be done ? */ spin_lock_irqsave(&st_gdata->lock, flags); for (i = ST_BT; i < ST_MAX_CHANNELS; i++) { if (st_gdata->list[i] != NULL) pr_err("%d not un-registered", i); st_gdata->list[i] = NULL; } st_gdata->protos_registered = 0; spin_unlock_irqrestore(&st_gdata->lock, flags); /* * signal to UIM via KIM that - * N_TI_WL ldisc is un-installed */ st_kim_complete(st_gdata->kim_data); st_gdata->tty = NULL; /* Flush any pending characters in the driver and discipline. */ tty_ldisc_flush(tty); tty_driver_flush_buffer(tty); spin_lock_irqsave(&st_gdata->lock, flags); /* empty out txq and tx_waitq */ skb_queue_purge(&st_gdata->txq); skb_queue_purge(&st_gdata->tx_waitq); /* reset the TTY Rx states of ST */ st_gdata->rx_count = 0; st_gdata->rx_state = ST_W4_PACKET_TYPE; kfree_skb(st_gdata->rx_skb); st_gdata->rx_skb = NULL; spin_unlock_irqrestore(&st_gdata->lock, flags); pr_debug("%s: done ", __func__); } static void st_tty_receive(struct tty_struct *tty, const unsigned char *data, char *tty_flags, int count) { #ifdef VERBOSE print_hex_dump(KERN_DEBUG, ">in>", DUMP_PREFIX_NONE, 16, 1, data, count, 0); #endif /* * if fw download is in progress then route incoming data * to KIM for validation */ st_recv(tty->disc_data, data, count); pr_debug("done %s", __func__); } /* wake-up function called in from the TTY layer * inside the internal wakeup function will be called */ static void st_tty_wakeup(struct tty_struct *tty) { struct st_data_s *st_gdata = tty->disc_data; pr_debug("%s ", __func__); /* don't do an wakeup for now */ clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); /* call our internal wakeup */ st_tx_wakeup((void *)st_gdata); } static void st_tty_flush_buffer(struct tty_struct *tty) { struct st_data_s *st_gdata = tty->disc_data; pr_debug("%s ", __func__); kfree_skb(st_gdata->tx_skb); st_gdata->tx_skb = NULL; tty->ops->flush_buffer(tty); return; } static struct tty_ldisc_ops st_ldisc_ops = { .magic = TTY_LDISC_MAGIC, .name = "n_st", .open = st_tty_open, .close = st_tty_close, .receive_buf = st_tty_receive, .write_wakeup = st_tty_wakeup, .flush_buffer = st_tty_flush_buffer, .owner = THIS_MODULE }; /********************************************************************/ int st_core_init(struct st_data_s **core_data) { struct st_data_s *st_gdata; long err; err = tty_register_ldisc(N_TI_WL, &st_ldisc_ops); if (err) { pr_err("error registering %d line discipline %ld", N_TI_WL, err); return err; } pr_debug("registered n_shared line discipline"); st_gdata = kzalloc(sizeof(struct st_data_s), GFP_KERNEL); if (!st_gdata) { pr_err("memory allocation failed"); err = tty_unregister_ldisc(N_TI_WL); if (err) pr_err("unable to un-register ldisc %ld", err); err = -ENOMEM; return err; } /* Initialize ST TxQ and Tx waitQ queue head. All BT/FM/GPS module skb's * will be pushed in this queue for actual transmission. */ skb_queue_head_init(&st_gdata->txq); skb_queue_head_init(&st_gdata->tx_waitq); /* Locking used in st_int_enqueue() to avoid multiple execution */ spin_lock_init(&st_gdata->lock); err = st_ll_init(st_gdata); if (err) { pr_err("error during st_ll initialization(%ld)", err); kfree(st_gdata); err = tty_unregister_ldisc(N_TI_WL); if (err) pr_err("unable to un-register ldisc"); return err; } *core_data = st_gdata; return 0; } void st_core_exit(struct st_data_s *st_gdata) { long err; /* internal module cleanup */ err = st_ll_deinit(st_gdata); if (err) pr_err("error during deinit of ST LL %ld", err); if (st_gdata != NULL) { /* Free ST Tx Qs and skbs */ skb_queue_purge(&st_gdata->txq); skb_queue_purge(&st_gdata->tx_waitq); kfree_skb(st_gdata->rx_skb); kfree_skb(st_gdata->tx_skb); /* TTY ldisc cleanup */ err = tty_unregister_ldisc(N_TI_WL); if (err) pr_err("unable to un-register ldisc %ld", err); /* free the global data pointer */ kfree(st_gdata); } }