text: /*
   *
   * Intel Management Engine Interface (Intel MEI) Linux driver
   * Copyright (c) 2003-2012, Intel Corporation.
   *
   * This program is free software; you can redistribute it and/or modify it
   * under the terms and conditions of the GNU General Public License,
   * version 2, as published by the Free Software Foundation.
   *
   * This program is distributed in the hope 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.
   *
   */
  
  
  #include <linux/export.h>
  #include <linux/kthread.h>
  #include <linux/interrupt.h>
  #include <linux/fs.h>
  #include <linux/jiffies.h>
  #include <linux/slab.h>
  #include <linux/pm_runtime.h>
  
  #include <linux/mei.h>
  
  #include "mei_dev.h"
  #include "hbm.h"
  #include "client.h"
  
  
  /**
   * mei_irq_compl_handler - dispatch complete handlers
   *	for the completed callbacks
   *
   * @dev: mei device
   * @compl_list: list of completed cbs
   */
  void mei_irq_compl_handler(struct mei_device *dev, struct mei_cl_cb *compl_list)
  {
  	struct mei_cl_cb *cb, *next;
  	struct mei_cl *cl;
  
  	list_for_each_entry_safe(cb, next, &compl_list->list, list) {
  		cl = cb->cl;
  		list_del_init(&cb->list);
  
  		dev_dbg(dev->dev, "completing call back.\n");
  		if (cl == &dev->iamthif_cl)
  			mei_amthif_complete(dev, cb);
  		else
  			mei_cl_complete(cl, cb);
  	}
  }
  EXPORT_SYMBOL_GPL(mei_irq_compl_handler);
  
  /**
   * mei_cl_hbm_equal - check if hbm is addressed to the client
   *
   * @cl: host client
   * @mei_hdr: header of mei client message
   *
   * Return: true if matches, false otherwise
   */
  static inline int mei_cl_hbm_equal(struct mei_cl *cl,
  			struct mei_msg_hdr *mei_hdr)
  {
  	return  mei_cl_host_addr(cl) == mei_hdr->host_addr &&
  		mei_cl_me_id(cl) == mei_hdr->me_addr;
  }
  
  /**
   * mei_irq_discard_msg  - discard received message
   *
   * @dev: mei device
   * @hdr: message header
   */
  void mei_irq_discard_msg(struct mei_device *dev, struct mei_msg_hdr *hdr)
  {
  	/*
  	 * no need to check for size as it is guarantied
  	 * that length fits into rd_msg_buf
  	 */
  	mei_read_slots(dev, dev->rd_msg_buf, hdr->length);
  	dev_dbg(dev->dev, "discarding message " MEI_HDR_FMT "\n",
  		MEI_HDR_PRM(hdr));
  }
  
  /**
   * mei_cl_irq_read_msg - process client message
   *
   * @cl: reading client
   * @mei_hdr: header of mei client message
   * @complete_list: completion list
   *
   * Return: always 0
   */
  int mei_cl_irq_read_msg(struct mei_cl *cl,
  		       struct mei_msg_hdr *mei_hdr,
  		       struct mei_cl_cb *complete_list)
  {
  	struct mei_device *dev = cl->dev;
  	struct mei_cl_cb *cb;
  	unsigned char *buffer = NULL;
  
  	cb = list_first_entry_or_null(&cl->rd_pending, struct mei_cl_cb, list);
  	if (!cb) {
  		cl_err(dev, cl, "pending read cb not found\n");
  		goto out;
  	}
  
  	if (!mei_cl_is_connected(cl)) {
  		cl_dbg(dev, cl, "not connected\n");
  		cb->status = -ENODEV;
  		goto out;
  	}
  
  	if (cb->buf.size == 0 || cb->buf.data == NULL) {
  		cl_err(dev, cl, "response buffer is not allocated.\n");
  		list_move_tail(&cb->list, &complete_list->list);
  		cb->status = -ENOMEM;
  		goto out;
  	}
  
  	if (cb->buf.size < mei_hdr->length + cb->buf_idx) {
  		cl_dbg(dev, cl, "message overflow. size %d len %d idx %ld\n",
  			cb->buf.size, mei_hdr->length, cb->buf_idx);
  		buffer = krealloc(cb->buf.data, mei_hdr->length + cb->buf_idx,
  				  GFP_KERNEL);
  
  		if (!buffer) {
  			cb->status = -ENOMEM;
  			list_move_tail(&cb->list, &complete_list->list);
  			goto out;
  		}
  		cb->buf.data = buffer;
  		cb->buf.size = mei_hdr->length + cb->buf_idx;
  	}
  
  	buffer = cb->buf.data + cb->buf_idx;
  	mei_read_slots(dev, buffer, mei_hdr->length);
  
  	cb->buf_idx += mei_hdr->length;
  
  	if (mei_hdr->msg_complete) {
  		cb->read_time = jiffies;
  		cl_dbg(dev, cl, "completed read length = %lu\n", cb->buf_idx);
  		list_move_tail(&cb->list, &complete_list->list);
  	} else {
  		pm_runtime_mark_last_busy(dev->dev);
  		pm_request_autosuspend(dev->dev);
  	}
  
  out:
  	if (!buffer)
  		mei_irq_discard_msg(dev, mei_hdr);
  
  	return 0;
  }
  
  /**
   * mei_cl_irq_disconnect_rsp - send disconnection response message
   *
   * @cl: client
   * @cb: callback block.
   * @cmpl_list: complete list.
   *
   * Return: 0, OK; otherwise, error.
   */
  static int mei_cl_irq_disconnect_rsp(struct mei_cl *cl, struct mei_cl_cb *cb,
  				     struct mei_cl_cb *cmpl_list)
  {
  	struct mei_device *dev = cl->dev;
  	u32 msg_slots;
  	int slots;
  	int ret;
  
  	slots = mei_hbuf_empty_slots(dev);
  	msg_slots = mei_data2slots(sizeof(struct hbm_client_connect_response));
  
  	if (slots < msg_slots)
  		return -EMSGSIZE;
  
  	ret = mei_hbm_cl_disconnect_rsp(dev, cl);
  	list_move_tail(&cb->list, &cmpl_list->list);
  
  	return ret;
  }
  
  /**
   * mei_cl_irq_read - processes client read related operation from the
   *	interrupt thread context - request for flow control credits
   *
   * @cl: client
   * @cb: callback block.
   * @cmpl_list: complete list.
   *
   * Return: 0, OK; otherwise, error.
   */
  static int mei_cl_irq_read(struct mei_cl *cl, struct mei_cl_cb *cb,
  			   struct mei_cl_cb *cmpl_list)
  {
  	struct mei_device *dev = cl->dev;
  	u32 msg_slots;
  	int slots;
  	int ret;
  
  	msg_slots = mei_data2slots(sizeof(struct hbm_flow_control));
  	slots = mei_hbuf_empty_slots(dev);
  
  	if (slots < msg_slots)
  		return -EMSGSIZE;
  
  	ret = mei_hbm_cl_flow_control_req(dev, cl);
  	if (ret) {
  		cl->status = ret;
  		cb->buf_idx = 0;
  		list_move_tail(&cb->list, &cmpl_list->list);
  		return ret;
  	}
  
  	list_move_tail(&cb->list, &cl->rd_pending);
  
  	return 0;
  }
  
  /**
   * mei_irq_read_handler - bottom half read routine after ISR to
   * handle the read processing.
   *
   * @dev: the device structure
   * @cmpl_list: An instance of our list structure
   * @slots: slots to read.
   *
   * Return: 0 on success, <0 on failure.
   */
  int mei_irq_read_handler(struct mei_device *dev,
  		struct mei_cl_cb *cmpl_list, s32 *slots)
  {
  	struct mei_msg_hdr *mei_hdr;
  	struct mei_cl *cl;
  	int ret;
  
  	if (!dev->rd_msg_hdr) {
  		dev->rd_msg_hdr = mei_read_hdr(dev);
  		(*slots)--;
  		dev_dbg(dev->dev, "slots =%08x.\n", *slots);
  	}
  	mei_hdr = (struct mei_msg_hdr *) &dev->rd_msg_hdr;
  	dev_dbg(dev->dev, MEI_HDR_FMT, MEI_HDR_PRM(mei_hdr));
  
  	if (mei_hdr->reserved || !dev->rd_msg_hdr) {
  		dev_err(dev->dev, "corrupted message header 0x%08X\n",
  				dev->rd_msg_hdr);
  		ret = -EBADMSG;
  		goto end;
  	}
  
  	if (mei_slots2data(*slots) < mei_hdr->length) {
  		dev_err(dev->dev, "less data available than length=%08x.\n",
  				*slots);
  		/* we can't read the message */
  		ret = -ENODATA;
  		goto end;
  	}
  
  	/*  HBM message */
  	if (mei_hdr->host_addr == 0 && mei_hdr->me_addr == 0) {
  		ret = mei_hbm_dispatch(dev, mei_hdr);
  		if (ret) {
  			dev_dbg(dev->dev, "mei_hbm_dispatch failed ret = %d\n",
  					ret);
  			goto end;
  		}
  		goto reset_slots;
  	}
  
  	/* find recipient cl */
  	list_for_each_entry(cl, &dev->file_list, link) {
  		if (mei_cl_hbm_equal(cl, mei_hdr)) {
  			cl_dbg(dev, cl, "got a message\n");
  			break;
  		}
  	}
  
  	/* if no recipient cl was found we assume corrupted header */
  	if (&cl->link == &dev->file_list) {
  		dev_err(dev->dev, "no destination client found 0x%08X\n",
  				dev->rd_msg_hdr);
  		ret = -EBADMSG;
  		goto end;
  	}
  
  	if (cl == &dev->iamthif_cl) {
  		ret = mei_amthif_irq_read_msg(cl, mei_hdr, cmpl_list);
  	} else {
  		ret = mei_cl_irq_read_msg(cl, mei_hdr, cmpl_list);
  	}
  
  
  reset_slots:
  	/* reset the number of slots and header */
  	*slots = mei_count_full_read_slots(dev);
  	dev->rd_msg_hdr = 0;
  
  	if (*slots == -EOVERFLOW) {
  		/* overflow - reset */
  		dev_err(dev->dev, "resetting due to slots overflow.\n");
  		/* set the event since message has been read */
  		ret = -ERANGE;
  		goto end;
  	}
  end:
  	return ret;
  }
  EXPORT_SYMBOL_GPL(mei_irq_read_handler);
  
  
  /**
   * mei_irq_write_handler -  dispatch write requests
   *  after irq received
   *
   * @dev: the device structure
   * @cmpl_list: An instance of our list structure
   *
   * Return: 0 on success, <0 on failure.
   */
  int mei_irq_write_handler(struct mei_device *dev, struct mei_cl_cb *cmpl_list)
  {
  
  	struct mei_cl *cl;
  	struct mei_cl_cb *cb, *next;
  	struct mei_cl_cb *list;
  	s32 slots;
  	int ret;
  
  
  	if (!mei_hbuf_acquire(dev))
  		return 0;
  
  	slots = mei_hbuf_empty_slots(dev);
  	if (slots <= 0)
  		return -EMSGSIZE;
  
  	/* complete all waiting for write CB */
  	dev_dbg(dev->dev, "complete all waiting for write cb.\n");
  
  	list = &dev->write_waiting_list;
  	list_for_each_entry_safe(cb, next, &list->list, list) {
  		cl = cb->cl;
  
  		cl->status = 0;
  		cl_dbg(dev, cl, "MEI WRITE COMPLETE\n");
  		cl->writing_state = MEI_WRITE_COMPLETE;
  		list_move_tail(&cb->list, &cmpl_list->list);
  	}
  
  	if (dev->wd_state == MEI_WD_STOPPING) {
  		dev->wd_state = MEI_WD_IDLE;
  		wake_up(&dev->wait_stop_wd);
  	}
  
  	if (mei_cl_is_connected(&dev->wd_cl)) {
  		if (dev->wd_pending &&
  		    mei_cl_flow_ctrl_creds(&dev->wd_cl) > 0) {
  			ret = mei_wd_send(dev);
  			if (ret)
  				return ret;
  			dev->wd_pending = false;
  		}
  	}
  
  	/* complete control write list CB */
  	dev_dbg(dev->dev, "complete control write list cb.\n");
  	list_for_each_entry_safe(cb, next, &dev->ctrl_wr_list.list, list) {
  		cl = cb->cl;
  		switch (cb->fop_type) {
  		case MEI_FOP_DISCONNECT:
  			/* send disconnect message */
  			ret = mei_cl_irq_disconnect(cl, cb, cmpl_list);
  			if (ret)
  				return ret;
  
  			break;
  		case MEI_FOP_READ:
  			/* send flow control message */
  			ret = mei_cl_irq_read(cl, cb, cmpl_list);
  			if (ret)
  				return ret;
  
  			break;
  		case MEI_FOP_CONNECT:
  			/* connect message */
  			ret = mei_cl_irq_connect(cl, cb, cmpl_list);
  			if (ret)
  				return ret;
  
  			break;
  		case MEI_FOP_DISCONNECT_RSP:
  			/* send disconnect resp */
  			ret = mei_cl_irq_disconnect_rsp(cl, cb, cmpl_list);
  			if (ret)
  				return ret;
  			break;
  
  		case MEI_FOP_NOTIFY_START:
  		case MEI_FOP_NOTIFY_STOP:
  			ret = mei_cl_irq_notify(cl, cb, cmpl_list);
  			if (ret)
  				return ret;
  			break;
  		default:
  			BUG();
  		}
  
  	}
  	/* complete  write list CB */
  	dev_dbg(dev->dev, "complete write list cb.\n");
  	list_for_each_entry_safe(cb, next, &dev->write_list.list, list) {
  		cl = cb->cl;
  		if (cl == &dev->iamthif_cl)
  			ret = mei_amthif_irq_write(cl, cb, cmpl_list);
  		else
  			ret = mei_cl_irq_write(cl, cb, cmpl_list);
  		if (ret)
  			return ret;
  	}
  	return 0;
  }
  EXPORT_SYMBOL_GPL(mei_irq_write_handler);
  
  
  /**
   * mei_connect_timeout  - connect/disconnect timeouts
   *
   * @cl: host client
   */
  static void mei_connect_timeout(struct mei_cl *cl)
  {
  	struct mei_device *dev = cl->dev;
  
  	if (cl->state == MEI_FILE_CONNECTING) {
  		if (dev->hbm_f_dot_supported) {
  			cl->state = MEI_FILE_DISCONNECT_REQUIRED;
  			wake_up(&cl->wait);
  			return;
  		}
  	}
  	mei_reset(dev);
  }
  
  /**
   * mei_timer - timer function.
   *
   * @work: pointer to the work_struct structure
   *
   */
  void mei_timer(struct work_struct *work)
  {
  	unsigned long timeout;
  	struct mei_cl *cl;
  
  	struct mei_device *dev = container_of(work,
  					struct mei_device, timer_work.work);
  
  
  	mutex_lock(&dev->device_lock);
  
  	/* Catch interrupt stalls during HBM init handshake */
  	if (dev->dev_state == MEI_DEV_INIT_CLIENTS &&
  	    dev->hbm_state != MEI_HBM_IDLE) {
  
  		if (dev->init_clients_timer) {
  			if (--dev->init_clients_timer == 0) {
  				dev_err(dev->dev, "timer: init clients timeout hbm_state = %d.\n",
  					dev->hbm_state);
  				mei_reset(dev);
  				goto out;
  			}
  		}
  	}
  
  	if (dev->dev_state != MEI_DEV_ENABLED)
  		goto out;
  
  	/*** connect/disconnect timeouts ***/
  	list_for_each_entry(cl, &dev->file_list, link) {
  		if (cl->timer_count) {
  			if (--cl->timer_count == 0) {
  				dev_err(dev->dev, "timer: connect/disconnect timeout.\n");
  				mei_connect_timeout(cl);
  				goto out;
  			}
  		}
  	}
  
  	if (!mei_cl_is_connected(&dev->iamthif_cl))
  		goto out;
  
  	if (dev->iamthif_stall_timer) {
  		if (--dev->iamthif_stall_timer == 0) {
  			dev_err(dev->dev, "timer: amthif  hanged.\n");
  			mei_reset(dev);
  			dev->iamthif_canceled = false;
  			dev->iamthif_state = MEI_IAMTHIF_IDLE;
  			dev->iamthif_timer = 0;
  
  			mei_io_cb_free(dev->iamthif_current_cb);
  			dev->iamthif_current_cb = NULL;
  
  			dev->iamthif_file_object = NULL;
  			mei_amthif_run_next_cmd(dev);
  		}
  	}
  
  	if (dev->iamthif_timer) {
  
  		timeout = dev->iamthif_timer +
  			mei_secs_to_jiffies(MEI_IAMTHIF_READ_TIMER);
  
  		dev_dbg(dev->dev, "dev->iamthif_timer = %ld\n",
  				dev->iamthif_timer);
  		dev_dbg(dev->dev, "timeout = %ld\n", timeout);
  		dev_dbg(dev->dev, "jiffies = %ld\n", jiffies);
  		if (time_after(jiffies, timeout)) {
  			/*
  			 * User didn't read the AMTHI data on time (15sec)
  			 * freeing AMTHI for other requests
  			 */
  
  			dev_dbg(dev->dev, "freeing AMTHI for other requests\n");
  
  			mei_io_list_flush(&dev->amthif_rd_complete_list,
  				&dev->iamthif_cl);
  			mei_io_cb_free(dev->iamthif_current_cb);
  			dev->iamthif_current_cb = NULL;
  
  			dev->iamthif_file_object->private_data = NULL;
  			dev->iamthif_file_object = NULL;
  			dev->iamthif_timer = 0;
  			mei_amthif_run_next_cmd(dev);
  
  		}
  	}
  out:
  	if (dev->dev_state != MEI_DEV_DISABLED)
  		schedule_delayed_work(&dev->timer_work, 2 * HZ);
  	mutex_unlock(&dev->device_lock);
  }
  