Quelle  trans.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0+
/* Copyright (c) 2015-2016 Quantenna Communications. All rights reserved. */

#include <linux/types.h>
#include <linux/export.h>
#include <linux/slab.h>

#include "core.h"
#include "commands.h"
#include "event.h"
#include "bus.h"

#define QTNF_DEF_SYNC_CMD_TIMEOUT (5 * HZ)

int qtnf_trans_send_cmd_with_resp(struct qtnf_bus *bus, struct sk_buff *cmd_skb,
      struct sk_buff **response_skb)
{
 struct qtnf_cmd_ctl_node *ctl_node = &bus->trans.curr_cmd;
 struct qlink_cmd *cmd = (void *)cmd_skb->data;
 int ret = 0;
 long status;
 bool resp_not_handled = true;
 struct sk_buff *resp_skb = NULL;

 if (unlikely(!response_skb)) {
  dev_kfree_skb(cmd_skb);
  return -EFAULT;
 }

 spin_lock(&ctl_node->resp_lock);
 ctl_node->seq_num++;
 cmd->seq_num = cpu_to_le16(ctl_node->seq_num);
 WARN(ctl_node->resp_skb, "qtnfmac: response skb not empty\n");
 ctl_node->waiting_for_resp = true;
 spin_unlock(&ctl_node->resp_lock);

 ret = qtnf_bus_control_tx(bus, cmd_skb);
 dev_kfree_skb(cmd_skb);

 if (unlikely(ret))
  goto out;

 status = wait_for_completion_interruptible_timeout(
      &ctl_node->cmd_resp_completion,
      QTNF_DEF_SYNC_CMD_TIMEOUT);

 spin_lock(&ctl_node->resp_lock);
 resp_not_handled = ctl_node->waiting_for_resp;
 resp_skb = ctl_node->resp_skb;
 ctl_node->resp_skb = NULL;
 ctl_node->waiting_for_resp = false;
 spin_unlock(&ctl_node->resp_lock);

 if (unlikely(status <= 0)) {
  if (status == 0) {
   ret = -ETIMEDOUT;
   pr_err("response timeout\n");
  } else {
   ret = -EINTR;
   pr_debug("interrupted\n");
  }
 }

 if (unlikely(!resp_skb || resp_not_handled)) {
  if (!ret)
   ret = -EFAULT;

  goto out;
 }

 ret = 0;
 *response_skb = resp_skb;

out:
 if (unlikely(resp_skb && resp_not_handled))
  dev_kfree_skb(resp_skb);

 return ret;
}

static void qtnf_trans_signal_cmdresp(struct qtnf_bus *bus, struct sk_buff *skb)
{
 struct qtnf_cmd_ctl_node *ctl_node = &bus->trans.curr_cmd;
 const struct qlink_resp *resp = (const struct qlink_resp *)skb->data;
 const u16 recvd_seq_num = le16_to_cpu(resp->seq_num);

 spin_lock(&ctl_node->resp_lock);

 if (unlikely(!ctl_node->waiting_for_resp)) {
  pr_err("unexpected response\n");
  goto out_err;
 }

 if (unlikely(recvd_seq_num != ctl_node->seq_num)) {
  pr_err("seq num mismatch\n");
  goto out_err;
 }

 ctl_node->resp_skb = skb;
 ctl_node->waiting_for_resp = false;

 spin_unlock(&ctl_node->resp_lock);

 complete(&ctl_node->cmd_resp_completion);
 return;

out_err:
 spin_unlock(&ctl_node->resp_lock);
 dev_kfree_skb(skb);
}

static int qtnf_trans_event_enqueue(struct qtnf_bus *bus, struct sk_buff *skb)
{
 struct qtnf_qlink_transport *trans = &bus->trans;

 if (likely(skb_queue_len(&trans->event_queue) <
     trans->event_queue_max_len)) {
  skb_queue_tail(&trans->event_queue, skb);
  queue_work(bus->workqueue, &bus->event_work);
 } else {
  pr_warn("event dropped due to queue overflow\n");
  dev_kfree_skb(skb);
  return -1;
 }

 return 0;
}

void qtnf_trans_init(struct qtnf_bus *bus)
{
 struct qtnf_qlink_transport *trans = &bus->trans;

 init_completion(&trans->curr_cmd.cmd_resp_completion);
 spin_lock_init(&trans->curr_cmd.resp_lock);

 spin_lock(&trans->curr_cmd.resp_lock);
 trans->curr_cmd.seq_num = 0;
 trans->curr_cmd.waiting_for_resp = false;
 trans->curr_cmd.resp_skb = NULL;
 spin_unlock(&trans->curr_cmd.resp_lock);

 /* Init event handling related fields */
 skb_queue_head_init(&trans->event_queue);
 trans->event_queue_max_len = QTNF_MAX_EVENT_QUEUE_LEN;
}

static void qtnf_trans_free_events(struct qtnf_bus *bus)
{
 struct sk_buff_head *event_queue = &bus->trans.event_queue;
 struct sk_buff *current_event_skb = skb_dequeue(event_queue);

 while (current_event_skb) {
  dev_kfree_skb_any(current_event_skb);
  current_event_skb = skb_dequeue(event_queue);
 }
}

void qtnf_trans_free(struct qtnf_bus *bus)
{
 if (!bus) {
  pr_err("invalid bus pointer\n");
  return;
 }

 qtnf_trans_free_events(bus);
}

int qtnf_trans_handle_rx_ctl_packet(struct qtnf_bus *bus, struct sk_buff *skb)
{
 const struct qlink_msg_header *header = (void *)skb->data;
 int ret = -1;

 if (unlikely(skb->len < sizeof(*header))) {
  pr_warn("packet is too small: %u\n", skb->len);
  dev_kfree_skb(skb);
  return -EINVAL;
 }

 if (unlikely(skb->len != le16_to_cpu(header->len))) {
  pr_warn("cmd reply length mismatch: %u != %u\n",
   skb->len, le16_to_cpu(header->len));
  dev_kfree_skb(skb);
  return -EFAULT;
 }

 switch (le16_to_cpu(header->type)) {
 case QLINK_MSG_TYPE_CMDRSP:
  if (unlikely(skb->len < sizeof(struct qlink_cmd))) {
   pr_warn("cmd reply too short: %u\n", skb->len);
   dev_kfree_skb(skb);
   break;
  }

  qtnf_trans_signal_cmdresp(bus, skb);
  break;
 case QLINK_MSG_TYPE_EVENT:
  if (unlikely(skb->len < sizeof(struct qlink_event))) {
   pr_warn("event too short: %u\n", skb->len);
   dev_kfree_skb(skb);
   break;
  }

  ret = qtnf_trans_event_enqueue(bus, skb);
  break;
 default:
  pr_warn("unknown packet type: %x\n", le16_to_cpu(header->type));
  dev_kfree_skb(skb);
  break;
 }

 return ret;
}
EXPORT_SYMBOL_GPL(qtnf_trans_handle_rx_ctl_packet);