path: root/os/io/pal.h

/*
    ChibiOS/RT - Copyright (C) 2006-2007 Giovanni Di Sirio.

    This file is part of ChibiOS/RT.

    ChibiOS/RT 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 3 of the License, or
    (at your option) any later version.

    ChibiOS/RT 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, see <http://www.gnu.org/licenses/>.
*/

/**
 * @file pal.h
 * @brief I/O Ports Abstraction Layer macros, types and structures
 * @addtogroup PAL
 * @{
 */

#ifndef _PAL_H_
#define _PAL_H_

/**
 * @brief Bits in a mode word dedicated as mode selector.
 * @details The other bits are not defined and may be used as device-specific
 *          option bits.
 */
#define PAL_MODE_MASK                   0xF

/**
 * @brief After reset state.
 * @details The state itself is not specified and is architecture dependent,
 *          it is guaranteed to be equal to the after-reset state. It is
 *          usually an input state.
 */
#define PAL_MODE_RESET                  0

/**
 * @brief Safe state for <b>unconnected</b> pads.
 * @details The state itself is not specified and is architecture dependent,
 *          it may be mapped on @p PAL_MODE_INPUT_PULLUP,
 *          @p PAL_MODE_INPUT_PULLDOWN or @p PAL_MODE_OUTPUT_PUSHPULL as
 *          example.
 */
#define PAL_MODE_UNCONNECTED            1

/**
 * @brief Regular input high-Z pad.
 */
#define PAL_MODE_INPUT                  2

/**
 * @brief Input pad with weak pull up resistor.
 */
#define PAL_MODE_INPUT_PULLUP           3

/**
 * @brief Input pad with weak pull down resistor.
 */
#define PAL_MODE_INPUT_PULLDOWN         4

/**
 * @brief Push-pull output pad.
 */
#define PAL_MODE_OUTPUT_PUSHPULL        5

/**
 * @brief Open-drain output pad.
 */
#define PAL_MODE_OUTPUT_OPENDRAIN       6

#ifndef _PAL_LLD_H_
#include "pal_lld.h"
#endif

/**
 * @brief Logical low state.
 */
#define PAL_LOW 0

/**
 * @brief Logical high state.
 */
#define PAL_HIGH 1

/**
 * @brief Port bit helper macro.
 * @details This macro calculates the mask of a bit within a port.
 *
 * @param[in] n the bit position within the port
 * @return The bit mask.
 */
#define PAL_PORT_BIT(n) ((ioportmask_t)(1 << (n)))


/**
 * @brief Bits group mask helper.
 * @details This macro calculates the mask of a bits group.
 *
 * @param[in] width the group width
 * @return The group mask.
 */
#define PAL_GROUP_MASK(width) ((ioportmask_t)(1 << (width)) - 1)

/**
 * @brief Data part of a static I/O bus initializer.
 * @details This macro should be used when statically initializing an I/O bus
 *          that is part of a bigger structure.
 *
 * @param name the name of the IOBus variable
 * @param port the I/O port descriptor
 * @param width the bus width in bits
 * @param offset the bus bit offset within the port
 */
#define _IOBUS_DATA(name, port, width, offset)                          \
  {port, PAL_GROUP_MASK(width), offset}

/**
 * @brief Static I/O bus initializer.
 *
 * @param name the name of the IOBus variable
 * @param port the I/O port descriptor
 * @param width the bus width in bits
 * @param offset the bus bit offset within the port
 */
#define IOBUS_DECL(name, port, width, offset)                           \
  IOBus name = _IOBUS_DATA(name, port, width, offset)

/**
 * @brief I/O bus descriptor.
 * @details This structure describes a group of contiguous digital I/O lines
 *          that have to be handled as bus.
 * @note I/O operations on a bus do not affect I/O lines on the same port but
 *       not belonging to the bus.
 */
typedef struct {
  /** Port identifier. */
  ioportid_t            bus_portid;
  /** Bus mask aligned to port bit 0. The bus mask implicitly define the bus
   *  width. */
  ioportmask_t          bus_mask;
  /** Offset, within the port, of the least significant bit of the bus. */
  uint_fast8_t          bus_offset;
} IOBus;

/**
 * @brief PAL subsystem initialization.
 *
 * @param[in] config pointer to an architecture specific configuration
 *            structure. This structure is defined in the low level driver
 *            header.
 */
#define palInit(config) pal_lld_init(config)

/**
 * @brief Reads the physical I/O port states.
 *
 * @param[in] port the port identifier
 * @return The port logical states.
 *
 * @note The default implementation always return zero and computes the
 *       parameter eventual side effects.
 */
#if !defined(pal_lld_readport) || defined(__DOXYGEN__)
#define palReadPort(port) ((void)(port), 0)
#else
#define palReadPort(port) pal_lld_readport(port)
#endif

/**
 * @brief Reads the output latch.
 * @details The purpose of this function is to read back the latched output
 *          value.
 *
 * @param[in] port the port identifier
 * @return The latched logical states.
 *
 * @note The default implementation always return zero and computes the
 *       parameter eventual side effects.
 */
#if !defined(pal_lld_readlatch) || defined(__DOXYGEN__)
#define palReadLatch(port) ((void)(port), 0)
#else
#define palReadLatch(port) pal_lld_readlatch(port)
#endif

/**
 * @brief Writes a bits mask on a I/O port.
 *
 * @param[in] port the port identifier
 * @param[in] bits the bits to be written on the specified port
 *
 * @note The default implementation does nothing except computing the
 *       parameters eventual side effects.
 */
#if !defined(pal_lld_writeport) || defined(__DOXYGEN__)
#define palWritePort(port, bits) ((void)(port), (void)(bits))
#else
#define palWritePort(port, bits) pal_lld_writeport(port, bits)
#endif

/**
 * @brief Sets a bits mask on a I/O port.
 *
 * @param[in] port the port identifier
 * @param[in] bits the bits to be ORed on the specified port
 *
 * @note The operation is not guaranteed to be atomic on all the architectures,
 *       for atomicity and/or portability reasons you may need to enclose port
 *       I/O operations between @p chSysLock() and @p chSysUnlock().
 * @note The default implementation is non atomic and not necessarily
 *       optimal. Low level drivers may  optimize the function by using
 *       specific hardware or coding.
 */
#if !defined(pal_lld_setport) || defined(__DOXYGEN__)
#define palSetPort(port, bits) {                                        \
  palWritePort(port, palReadLatch(port) | (bits));                      \
}
#else
#define palSetPort(port, bits) pal_lld_setport(port, bits)
#endif

/**
 * @brief Clears a bits mask on a I/O port.
 *
 * @param[in] port the port identifier
 * @param[in] bits the bits to be cleared on the specified port
 *
 * @note The operation is not guaranteed to be atomic on all the architectures,
 *       for atomicity and/or portability reasons you may need to enclose port
 *       I/O operations between @p chSysLock() and @p chSysUnlock().
 * @note The default implementation is non atomic and not necessarily
 *       optimal. Low level drivers may  optimize the function by using
 *       specific hardware or coding.
 */
#if !defined(pal_lld_clearport) || defined(__DOXYGEN__)
#define palClearPort(port, bits) {                                      \
  palWritePort(port, palReadLatch(port) & ~(bits));                     \
}
#else
#define palClearPort(port, bits) pal_lld_clearport(port, bits)
#endif

/**
 * @brief Toggles a bits mask on a I/O port.
 *
 * @param[in] port the port identifier
 * @param[in] bits the bits to be XORed on the specified port
 *
 * @note The operation is not guaranteed to be atomic on all the architectures,
 *       for atomicity and/or portability reasons you may need to enclose port
 *       I/O operations between @p chSysLock() and @p chSysUnlock().
 * @note The default implementation is non atomic and not necessarily
 *       optimal. Low level drivers may  optimize the function by using
 *       specific hardware or coding.
 */
#if !defined(pal_lld_toggleport) || defined(__DOXYGEN__)
#define palTogglePort(port, bits) {                                     \
  palWritePort(port, palReadLatch(port) ^ (bits));                      \
}
#else
#define palTogglePort(port, bits) pal_lld_toggleport(port, bits)
#endif

/**
 * @brief Reads a group of bits.
 *
 * @param[in] port the port identifier
 * @param[in] mask the group mask
 * @param[in] offset the group bit offset within the port
 * @return The group logical states.
 */
#if !defined(pal_lld_readgroup) || defined(__DOXYGEN__)
#define palReadGroup(port, mask, offset)                               \
  ((palReadPort(port) >> (offset)) & (mask))
#else
#define palReadGroup(port, mask, offset) pal_lld_readgroup(port, mask, offset)
#endif

/**
 * @brief Writes a group of bits.
 *
 * @param[in] port the port identifier
 * @param[in] mask the group mask
 * @param[in] offset the group bit offset within the port
 * @param[in] bits the bits to be written. Values exceeding the group width
 *            are masked.
 */
#if !defined(pal_lld_writegroup) || defined(__DOXYGEN__)
#define palWriteGroup(port, mask, offset, bits) {                       \
  palWritePort(port, (palReadLatch(port) & ~((mask) << (offset))) |     \
                     (((bits) & (mask)) << (offset)));                  \
}
#else
#define palWriteGroup(port, mask, offset, bits)                         \
  pal_lld_writegroup(port, mask, offset, bits)
#endif


/**
 * @brief Pads group mode setup.
 * @details This function programs a pads group belonging to the same port
 *          with the specified mode.
 *
 * @param[in] port the port identifier
 * @param[in] mask the group mask
 * @param[in] mode the setup mode
 *
 * @note Programming an unknown or unsupported mode is silently ignored.
 */
#if !defined(pal_lld_setgroupmode) || defined(__DOXYGEN__)
#define palSetGroupMode(port, mask, mode)
#else
#define palSetGroupMode(port, mask, mode) pal_lld_setgroupmode(port, mask, mode)
#endif

/**
 * @brief Reads an input pad logical state.
 *
 * @param[in] port the port identifier
 * @param[in] pad the pad number within the port
 * @return The logical state.
 * @retval 0 low logical state.
 * @retval 1 high logical state.
 *
 * @note The default implementation not necessarily optimal. Low level drivers
 *       may  optimize the function by using specific hardware or coding.
 * @note The default implementation internally uses the @p palReadPort().
 */
#if !defined(pal_lld_readpad) || defined(__DOXYGEN__)
#define palReadPad(port, pad) ((palReadPort(port) >> (pad)) & 1)
#else
#define palReadPad(port, pad) pal_lld_readpad(port, pad)
#endif

/**
 * @brief Writes a logical state on an output pad.
 *
 * @param[in] port the port identifier
 * @param[in] pad the pad number within the port
 * @param[out] bit the logical value, the value must be @p 0 or @p 1
 *
 * @note The operation is not guaranteed to be atomic on all the architectures,
 *       for atomicity and/or portability reasons you may need to enclose port
 *       I/O operations between @p chSysLock() and @p chSysUnlock().
 * @note The default implementation is non atomic and not necessarily
 *       optimal. Low level drivers may  optimize the function by using
 *       specific hardware or coding.
 * @note The default implementation internally uses the @p palReadLatch() and
 *       @p palWritePort().
 */
#if !defined(pal_lld_writepad) || defined(__DOXYGEN__)
#define palWritePad(port, pad, bit) {                                   \
  palWritePort(port, (palReadLatch(port) & ~PAL_PORT_BIT(pad)) |        \
                     (((bit) & 1) << pad));                             \
}
#else
#define palWritePad(port, pad, bit) pal_lld_writepad(port, pad, bit)
#endif

/**
 * @brief Sets a pad logical state to @p 1.
 *
 * @param[in] port the port identifier
 * @param[in] pad the pad number within the port
 *
 * @note The operation is not guaranteed to be atomic on all the architectures,
 *       for atomicity and/or portability reasons you may need to enclose port
 *       I/O operations between @p chSysLock() and @p chSysUnlock().
 * @note The default implementation is non atomic and not necessarily
 *       optimal. Low level drivers may  optimize the function by using
 *       specific hardware or coding.
 * @note The default implementation internally uses the @p palSetPort().
 */
#if !defined(pal_lld_setpad) || defined(__DOXYGEN__)
#define palSetPad(port, pad) palSetPort(port, PAL_PORT_BIT(pad))
#else
#define palSetPad(port, pad) pal_lld_setpad(port, pad)
#endif

/**
 * @brief Clears a pad logical state to @p 0.
 *
 * @param[in] port the port identifier
 * @param[in] pad the pad number within the port
 *
 * @note The operation is not guaranteed to be atomic on all the architectures,
 *       for atomicity and/or portability reasons you may need to enclose port
 *       I/O operations between @p chSysLock() and @p chSysUnlock().
 * @note The default implementation is non atomic and not necessarily
 *       optimal. Low level drivers may  optimize the function by using
 *       specific hardware or coding.
 * @note The default implementation internally uses the @p palClearPort().
 */
#if !defined(pal_lld_clearpad) || defined(__DOXYGEN__)
#define palClearPad(port, pad) palClearPort(port, PAL_PORT_BIT(pad))
#else
#define palClearPad(port, pad) pal_lld_clearpad(port, pad)
#endif

/**
 * @brief Toggles a pad logical state.
 *
 * @param[in] port the port identifier
 * @param[in] pad the pad number within the port
 *
 * @note The operation is not guaranteed to be atomic on all the architectures,
 *       for atomicity and/or portability reasons you may need to enclose port
 *       I/O operations between @p chSysLock() and @p chSysUnlock().
 * @note The default implementation is non atomic and not necessarily
 *       optimal. Low level drivers may  optimize the function by using
 *       specific hardware or coding.
 * @note The default implementation internally uses the @p palTogglePort().
 */
#if !defined(pal_lld_togglepad) || defined(__DOXYGEN__)
#define palTogglePad(port, pad) palTogglePort(port, PAL_PORT_BIT(pad))
#else
#define palTogglePad(port, pad) pal_lld_togglepad(port, pad)
#endif


/**
 * @brief Pad mode setup.
 * @details This function programs a pad with the specified mode.
 *
 * @param[in] port the port identifier
 * @param[in] pad the pad number within the port
 * @param[in] mode the setup mode
 *
 * @note The default implementation not necessarily optimal. Low level drivers
 *       may  optimize the function by using specific hardware or coding.
 * @note Programming an unknown or unsupported mode is silently ignored.
 */
#if !defined(pal_lld_setpadmode) || defined(__DOXYGEN__)
#define palSetPadMode(port, pad, mode)                                  \
  palSetGroupMode(port, PAL_PORT_BIT(pad), mode)
#else
#define palSetPadMode(port, pad, mode) pal_lld_setpadmode(port, pad, mode)
#endif

#ifdef __cplusplus
extern "C" {
#endif
  ioportmask_t palReadBus(IOBus *bus);
  void palWriteBus(IOBus *bus, ioportmask_t bits);
  void palSetBusMode(IOBus *bus, uint_fast8_t mode);
#ifdef __cplusplus
}
#endif

#endif /* _PAL_H_ */

/** @} */