text: /*
   *  hdac-ext-controller.c - HD-audio extended controller functions.
   *
   *  Copyright (C) 2014-2015 Intel Corp
   *  Author: Jeeja KP <jeeja.kp@intel.com>
   *  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   *
   *  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; version 2 of the License.
   *
   *  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.
   *
   * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   */
  
  #include <linux/delay.h>
  #include <linux/slab.h>
  #include <sound/hda_register.h>
  #include <sound/hdaudio_ext.h>
  
  /*
   * maximum HDAC capablities we should parse to avoid endless looping:
   * currently we have 4 extended caps, so this is future proof for now.
   * extend when this limit is seen meeting in real HW
   */
  #define HDAC_MAX_CAPS 10
  
  /*
   * processing pipe helpers - these helpers are useful for dealing with HDA
   * new capability of processing pipelines
   */
  
  /**
   * snd_hdac_ext_bus_ppcap_enable - enable/disable processing pipe capability
   * @ebus: HD-audio extended core bus
   * @enable: flag to turn on/off the capability
   */
  void snd_hdac_ext_bus_ppcap_enable(struct hdac_bus *bus, bool enable)
  {
  
  	if (!bus->ppcap) {
  		dev_err(bus->dev, "Address of PP capability is NULL");
  		return;
  	}
  
  	if (enable)
  		snd_hdac_updatel(bus->ppcap, AZX_REG_PP_PPCTL,
  				 AZX_PPCTL_GPROCEN, AZX_PPCTL_GPROCEN);
  	else
  		snd_hdac_updatel(bus->ppcap, AZX_REG_PP_PPCTL,
  				 AZX_PPCTL_GPROCEN, 0);
  }
  EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_ppcap_enable);
  
  /**
   * snd_hdac_ext_bus_ppcap_int_enable - ppcap interrupt enable/disable
   * @ebus: HD-audio extended core bus
   * @enable: flag to enable/disable interrupt
   */
  void snd_hdac_ext_bus_ppcap_int_enable(struct hdac_bus *bus, bool enable)
  {
  
  	if (!bus->ppcap) {
  		dev_err(bus->dev, "Address of PP capability is NULL\n");
  		return;
  	}
  
  	if (enable)
  		snd_hdac_updatel(bus->ppcap, AZX_REG_PP_PPCTL,
  				 AZX_PPCTL_PIE, AZX_PPCTL_PIE);
  	else
  		snd_hdac_updatel(bus->ppcap, AZX_REG_PP_PPCTL,
  				 AZX_PPCTL_PIE, 0);
  }
  EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_ppcap_int_enable);
  
  /*
   * Multilink helpers - these helpers are useful for dealing with HDA
   * new multilink capability
   */
  
  /**
   * snd_hdac_ext_bus_get_ml_capabilities - get multilink capability
   * @ebus: HD-audio extended core bus
   *
   * This will parse all links and read the mlink capabilities and add them
   * in hlink_list of extended hdac bus
   * Note: this will be freed on bus exit by driver
   */
  int snd_hdac_ext_bus_get_ml_capabilities(struct hdac_bus *bus)
  {
  	int idx;
  	u32 link_count;
  	struct hdac_ext_link *hlink;
  
  	link_count = readl(bus->mlcap + AZX_REG_ML_MLCD) + 1;
  
  	dev_dbg(bus->dev, "In %s Link count: %d\n", __func__, link_count);
  
  	for (idx = 0; idx < link_count; idx++) {
  		hlink  = kzalloc(sizeof(*hlink), GFP_KERNEL);
  		if (!hlink)
  			return -ENOMEM;
  		hlink->index = idx;
  		hlink->bus = bus;
  		hlink->ml_addr = bus->mlcap + AZX_ML_BASE +
  					(AZX_ML_INTERVAL * idx);
  		hlink->lcaps  = readl(hlink->ml_addr + AZX_REG_ML_LCAP);
  		hlink->lsdiid = readw(hlink->ml_addr + AZX_REG_ML_LSDIID);
  
  		/* since link in On, update the ref */
  		hlink->ref_count = 1;
  
  		list_add_tail(&hlink->list, &bus->hlink_list);
  	}
  
  	return 0;
  }
  EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_get_ml_capabilities);
  
  /**
   * snd_hdac_link_free_all- free hdac extended link objects
   *
   * @ebus: HD-audio ext core bus
   */
  
  void snd_hdac_link_free_all(struct hdac_bus *bus)
  {
  	struct hdac_ext_link *l;
  
  	while (!list_empty(&bus->hlink_list)) {
  		l = list_first_entry(&bus->hlink_list, struct hdac_ext_link, list);
  		list_del(&l->list);
  		kfree(l);
  	}
  }
  EXPORT_SYMBOL_GPL(snd_hdac_link_free_all);
  
  /**
   * snd_hdac_ext_bus_get_link_index - get link based on codec name
   * @ebus: HD-audio extended core bus
   * @codec_name: codec name
   */
  struct hdac_ext_link *snd_hdac_ext_bus_get_link(struct hdac_bus *bus,
  						 const char *codec_name)
  {
  	int i;
  	struct hdac_ext_link *hlink = NULL;
  	int bus_idx, addr;
  
  	if (sscanf(codec_name, "ehdaudio%dD%d", &bus_idx, &addr) != 2)
  		return NULL;
  	if (bus->idx != bus_idx)
  		return NULL;
  
  	list_for_each_entry(hlink, &bus->hlink_list, list) {
  		for (i = 0; i < HDA_MAX_CODECS; i++) {
  			if (hlink->lsdiid & (0x1 << addr))
  				return hlink;
  		}
  	}
  
  	return NULL;
  }
  EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_get_link);
  
  static int check_hdac_link_power_active(struct hdac_ext_link *link, bool enable)
  {
  	int timeout;
  	u32 val;
  	int mask = (1 << AZX_MLCTL_CPA_SHIFT);
  
  	udelay(3);
  	timeout = 150;
  
  	do {
  		val = readl(link->ml_addr + AZX_REG_ML_LCTL);
  		if (enable) {
  			if (((val & mask) >> AZX_MLCTL_CPA_SHIFT))
  				return 0;
  		} else {
  			if (!((val & mask) >> AZX_MLCTL_CPA_SHIFT))
  				return 0;
  		}
  		udelay(3);
  	} while (--timeout);
  
  	return -EIO;
  }
  
  /**
   * snd_hdac_ext_bus_link_power_up -power up hda link
   * @link: HD-audio extended link
   */
  int snd_hdac_ext_bus_link_power_up(struct hdac_ext_link *link)
  {
  	snd_hdac_updatel(link->ml_addr, AZX_REG_ML_LCTL,
  			 AZX_MLCTL_SPA, AZX_MLCTL_SPA);
  
  	return check_hdac_link_power_active(link, true);
  }
  EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_link_power_up);
  
  /**
   * snd_hdac_ext_bus_link_power_down -power down hda link
   * @link: HD-audio extended link
   */
  int snd_hdac_ext_bus_link_power_down(struct hdac_ext_link *link)
  {
  	snd_hdac_updatel(link->ml_addr, AZX_REG_ML_LCTL, AZX_MLCTL_SPA, 0);
  
  	return check_hdac_link_power_active(link, false);
  }
  EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_link_power_down);
  
  /**
   * snd_hdac_ext_bus_link_power_up_all -power up all hda link
   * @ebus: HD-audio extended bus
   */
  int snd_hdac_ext_bus_link_power_up_all(struct hdac_bus *bus)
  {
  	struct hdac_ext_link *hlink = NULL;
  	int ret;
  
  	list_for_each_entry(hlink, &bus->hlink_list, list) {
  		snd_hdac_updatel(hlink->ml_addr, AZX_REG_ML_LCTL,
  				 AZX_MLCTL_SPA, AZX_MLCTL_SPA);
  		ret = check_hdac_link_power_active(hlink, true);
  		if (ret < 0)
  			return ret;
  	}
  
  	return 0;
  }
  EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_link_power_up_all);
  
  /**
   * snd_hdac_ext_bus_link_power_down_all -power down all hda link
   * @ebus: HD-audio extended bus
   */
  int snd_hdac_ext_bus_link_power_down_all(struct hdac_bus *bus)
  {
  	struct hdac_ext_link *hlink = NULL;
  	int ret;
  
  	list_for_each_entry(hlink, &bus->hlink_list, list) {
  		snd_hdac_updatel(hlink->ml_addr, AZX_REG_ML_LCTL,
  				 AZX_MLCTL_SPA, 0);
  		ret = check_hdac_link_power_active(hlink, false);
  		if (ret < 0)
  			return ret;
  	}
  
  	return 0;
  }
  EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_link_power_down_all);
  
  int snd_hdac_ext_bus_link_get(struct hdac_bus *bus,
  				struct hdac_ext_link *link)
  {
  	int ret = 0;
  
  	mutex_lock(&bus->lock);
  
  	/*
  	 * if we move from 0 to 1, count will be 1 so power up this link
  	 * as well, also check the dma status and trigger that
  	 */
  	if (++link->ref_count == 1) {
  		if (!bus->cmd_dma_state) {
  			snd_hdac_bus_init_cmd_io(bus);
  			bus->cmd_dma_state = true;
  		}
  
  		ret = snd_hdac_ext_bus_link_power_up(link);
  
  		/*
  		 *  wait for 521usec for codec to report status
  		 *  HDA spec section 4.3 - Codec Discovery
  		 */
  		udelay(521);
  		bus->codec_mask = snd_hdac_chip_readw(bus, STATESTS);
  		dev_dbg(bus->dev, "codec_mask = 0x%lx\n", bus->codec_mask);
  		snd_hdac_chip_writew(bus, STATESTS, bus->codec_mask);
  	}
  
  	mutex_unlock(&bus->lock);
  	return ret;
  }
  EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_link_get);
  
  int snd_hdac_ext_bus_link_put(struct hdac_bus *bus,
  				struct hdac_ext_link *link)
  {
  	int ret = 0;
  	struct hdac_ext_link *hlink;
  	bool link_up = false;
  
  	mutex_lock(&bus->lock);
  
  	/*
  	 * if we move from 1 to 0, count will be 0
  	 * so power down this link as well
  	 */
  	if (--link->ref_count == 0) {
  		ret = snd_hdac_ext_bus_link_power_down(link);
  
  		/*
  		 * now check if all links are off, if so turn off
  		 * cmd dma as well
  		 */
  		list_for_each_entry(hlink, &bus->hlink_list, list) {
  			if (hlink->ref_count) {
  				link_up = true;
  				break;
  			}
  		}
  
  		if (!link_up) {
  			snd_hdac_bus_stop_cmd_io(bus);
  			bus->cmd_dma_state = false;
  		}
  	}
  
  	mutex_unlock(&bus->lock);
  	return ret;
  }
  EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_link_put);
  