text: /* SPDX-License-Identifier: GPL-2.0+ */
  /* vim: set ts=8 sw=8 noet tw=80 nowrap: */
  /*
   *  comedi/drivers/ni_routes.h
   *  Route information for NI boards.
   *
   *  COMEDI - Linux Control and Measurement Device Interface
   *  Copyright (C) 2016 Spencer E. Olson <olsonse@umich.edu>
   *
   *  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; either version 2 of the License, or
   *  (at your option) any later version.
   *
   *  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.
   */
  
  #ifndef _COMEDI_DRIVERS_NI_ROUTES_H
  #define _COMEDI_DRIVERS_NI_ROUTES_H
  
  #include <linux/types.h>
  #include <linux/errno.h>
  
  #ifndef NI_ROUTE_VALUE_EXTERNAL_CONVERSION
  #include <linux/bitops.h>
  #endif
  
  #include "../comedi.h"
  
  /**
   * struct ni_route_set - Set of destinations with a common source.
   * @dest: Destination of all sources in this route set.
   * @n_src: Number of sources for this route set.
   * @src: List of sources that all map to the same destination.
   */
  struct ni_route_set {
  	int dest;
  	int n_src;
  	int *src;
  };
  
  /**
   * struct ni_device_routes - List of all src->dest sets for a particular device.
   * @device: Name of board/device (e.g. pxi-6733).
   * @n_route_sets: Number of route sets that are valid for this device.
   * @routes: List of route sets that are valid for this device.
   */
  struct ni_device_routes {
  	const char *device;
  	int n_route_sets;
  	struct ni_route_set *routes;
  };
  
  /**
   * struct ni_route_tables - Register values and valid routes for a device.
   * @valid_routes: Pointer to a all valid route sets for a single device.
   * @route_values: Pointer to register values for all routes for the family to
   *		  which the device belongs.
   *
   * Link to the valid src->dest routes and the register values used to assign
   * such routes for that particular device.
   */
  struct ni_route_tables {
  	const struct ni_device_routes *valid_routes;
  	const u8 *route_values;
  };
  
  /*
   * ni_assign_device_routes() - Assign the proper lookup table for NI signal
   *			       routing to the specified NI device.
   *
   * Return: -ENODATA if assignment was not successful; 0 if successful.
   */
  int ni_assign_device_routes(const char *device_family,
  			    const char *board_name,
  			    const char *alt_board_name,
  			    struct ni_route_tables *tables);
  
  /*
   * ni_find_route_set() - Finds the proper route set with the specified
   *			 destination.
   * @destination: Destination of which to search for the route set.
   * @valid_routes: Pointer to device routes within which to search.
   *
   * Return: NULL if no route_set is found with the specified @destination;
   *	otherwise, a pointer to the route_set if found.
   */
  const struct ni_route_set *
  ni_find_route_set(const int destination,
  		  const struct ni_device_routes *valid_routes);
  
  /*
   * ni_route_set_has_source() - Determines whether the given source is in
   *			       included given route_set.
   *
   * Return: true if found; false otherwise.
   */
  bool ni_route_set_has_source(const struct ni_route_set *routes, const int src);
  
  /*
   * ni_route_to_register() - Validates and converts the specified signal route
   *			    (src-->dest) to the value used at the appropriate
   *			    register.
   * @src:	global-identifier for route source
   * @dest:	global-identifier for route destination
   * @tables:	pointer to relevant set of routing tables.
   *
   * Generally speaking, most routes require the first six bits and a few require
   * 7 bits.  Special handling is given for the return value when the route is to
   * be handled by the RTSI sub-device.  In this case, the returned register may
   * not be sufficient to define the entire route path, but rather may only
   * indicate the intermediate route.  For example, if the route must go through
   * the RGOUT0 pin, the (src->RGOUT0) register value will be returned.
   * Similarly, if the route must go through the NI_RTSI_BRD lines, the BIT(6)
   * will be set:
   *
   * if route does not need RTSI_BRD lines:
   *   bits 0:7 : register value
   *              for a route that must go through RGOUT0 pin, this will be equal
   *              to the (src->RGOUT0) register value.
   * else: * route is (src->RTSI_BRD(x), RTSI_BRD(x)->TRIGGER_LINE(i)) *
   *   bits 0:5 : zero
   *   bits 6   : set to 1
   *   bits 7:7 : zero
   *
   * Return: register value to be used for source at destination with special
   *	cases given above; Otherwise, -1 if the specified route is not valid for
   *	this particular device.
   */
  s8 ni_route_to_register(const int src, const int dest,
  			const struct ni_route_tables *tables);
  
  static inline bool ni_rtsi_route_requires_mux(s8 value)
  {
  	return value & BIT(6);
  }
  
  /*
   * ni_lookup_route_register() - Look up a register value for a particular route
   *				without checking whether the route is valid for
   *				the particular device.
   * @src:	global-identifier for route source
   * @dest:	global-identifier for route destination
   * @tables:	pointer to relevant set of routing tables.
   *
   * Return: -EINVAL if the specified route is not valid for this device family.
   */
  s8 ni_lookup_route_register(int src, int dest,
  			    const struct ni_route_tables *tables);
  
  /**
   * route_is_valid() - Determines whether the specified signal route (src-->dest)
   *		      is valid for the given NI comedi_device.
   * @src:	global-identifier for route source
   * @dest:	global-identifier for route destination
   * @tables:	pointer to relevant set of routing tables.
   *
   * Return: True if the route is valid, otherwise false.
   */
  static inline bool route_is_valid(const int src, const int dest,
  				  const struct ni_route_tables *tables)
  {
  	return ni_route_to_register(src, dest, tables) >= 0;
  }
  
  /*
   * ni_is_cmd_dest() - Determine whether the given destination is only
   *		      configurable via a comedi_cmd struct.
   * @dest: Destination to test.
   */
  bool ni_is_cmd_dest(int dest);
  
  static inline bool channel_is_pfi(int channel)
  {
  	return NI_PFI(0) <= channel && channel <= NI_PFI(-1);
  }
  
  static inline bool channel_is_rtsi(int channel)
  {
  	return TRIGGER_LINE(0) <= channel && channel <= TRIGGER_LINE(-1);
  }
  
  static inline bool channel_is_ctr(int channel)
  {
  	return channel >= NI_COUNTER_NAMES_BASE &&
  	       channel <= NI_COUNTER_NAMES_MAX;
  }
  
  /*
   * ni_count_valid_routes() - Count the number of valid routes.
   * @tables: Routing tables for which to count all valid routes.
   */
  unsigned int ni_count_valid_routes(const struct ni_route_tables *tables);
  
  /*
   * ni_get_valid_routes() - Implements INSN_DEVICE_CONFIG_GET_ROUTES.
   * @tables:	pointer to relevant set of routing tables.
   * @n_pairs:	Number of pairs for which memory is allocated by the user.  If
   *		the user specifies '0', only the number of available pairs is
   *		returned.
   * @pair_data:	Pointer to memory allocated to return pairs back to user.  Each
   *		even, odd indexed member of this array will hold source,
   *		destination of a route pair respectively.
   *
   * Return: the number of valid routes if n_pairs == 0; otherwise, the number of
   *	valid routes copied.
   */
  unsigned int ni_get_valid_routes(const struct ni_route_tables *tables,
  				 unsigned int n_pairs,
  				 unsigned int *pair_data);
  
  /*
   * ni_sort_device_routes() - Sort the list of valid device signal routes in
   *			     preparation for use.
   * @valid_routes:	pointer to ni_device_routes struct to sort.
   */
  void ni_sort_device_routes(struct ni_device_routes *valid_routes);
  
  /*
   * ni_find_route_source() - Finds the signal source corresponding to a signal
   *			    route (src-->dest) of the specified routing register
   *			    value and the specified route destination on the
   *			    specified device.
   *
   * Note that this function does _not_ validate the source based on device
   * routes.
   *
   * Return: The NI signal value (e.g. NI_PFI(0) or PXI_Clk10) if found.
   *	If the source was not found (i.e. the register value is not
   *	valid for any routes to the destination), -EINVAL is returned.
   */
  int ni_find_route_source(const u8 src_sel_reg_value, const int dest,
  			 const struct ni_route_tables *tables);
  
  /**
   * route_register_is_valid() - Determines whether the register value for the
   *			       specified route destination on the specified
   *			       device is valid.
   */
  static inline bool route_register_is_valid(const u8 src_sel_reg_value,
  					   const int dest,
  					   const struct ni_route_tables *tables)
  {
  	return ni_find_route_source(src_sel_reg_value, dest, tables) >= 0;
  }
  
  /**
   * ni_get_reg_value_roffs() - Determines the proper register value for a
   *			      particular valid NI signal/terminal route.
   * @src:	Either a direct register value or one of NI_* signal names.
   * @dest:	global-identifier for route destination
   * @tables:	pointer to relevant set of routing tables.
   * @direct_reg_offset:
   *		Compatibility compensation argument.  This argument allows us to
   *		arbitrarily apply an offset to src if src is a direct register
   *		value reference.  This is necessary to be compatible with
   *		definitions of register values as previously exported directly
   *		to user space.
   *
   * Return: the register value (>0) to be used at the destination if the src is
   *	valid for the given destination; -1 otherwise.
   */
  static inline s8 ni_get_reg_value_roffs(int src, const int dest,
  					const struct ni_route_tables *tables,
  					const int direct_reg_offset)
  {
  	if (src < NI_NAMES_BASE) {
  		src += direct_reg_offset;
  		/*
  		 * In this case, the src is expected to actually be a register
  		 * value.
  		 */
  		if (route_register_is_valid(src, dest, tables))
  			return src;
  		return -1;
  	}
  
  	/*
  	 * Otherwise, the src is expected to be one of the abstracted NI
  	 * signal/terminal names.
  	 */
  	return ni_route_to_register(src, dest, tables);
  }
  
  static inline int ni_get_reg_value(const int src, const int dest,
  				   const struct ni_route_tables *tables)
  {
  	return ni_get_reg_value_roffs(src, dest, tables, 0);
  }
  
  /**
   * ni_check_trigger_arg_roffs() - Checks the trigger argument (*_arg) of an NI
   *				  device to ensure that the *_arg value
   *				  corresponds to _either_ a valid register value
   *				  to define a trigger source, _or_ a valid NI
   *				  signal/terminal name that has a valid route to
   *				  the destination on the particular device.
   * @src:	Either a direct register value or one of NI_* signal names.
   * @dest:	global-identifier for route destination
   * @tables:	pointer to relevant set of routing tables.
   * @direct_reg_offset:
   *		Compatibility compensation argument.  This argument allows us to
   *		arbitrarily apply an offset to src if src is a direct register
   *		value reference.  This is necessary to be compatible with
   *		definitions of register values as previously exported directly
   *		to user space.
   *
   * Return: 0 if the src (either register value or NI signal/terminal name) is
   *	valid for the destination; -EINVAL otherwise.
   */
  static inline
  int ni_check_trigger_arg_roffs(int src, const int dest,
  			       const struct ni_route_tables *tables,
  			       const int direct_reg_offset)
  {
  	if (ni_get_reg_value_roffs(src, dest, tables, direct_reg_offset) < 0)
  		return -EINVAL;
  	return 0;
  }
  
  static inline int ni_check_trigger_arg(const int src, const int dest,
  				       const struct ni_route_tables *tables)
  {
  	return ni_check_trigger_arg_roffs(src, dest, tables, 0);
  }
  
  #endif /* _COMEDI_DRIVERS_NI_ROUTES_H */
  