iomap.h

/* Copyright © 2015-2018 Pascal JEAN, All rights reserved.
   This file is part of the Piduino Library.
 
   The Piduino Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 3 of the License, or (at your option) any later version.
 
   The Piduino Library 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
   Lesser General Public License for more details.
 
   You should have received a copy of the GNU Lesser General Public License
   along with the Piduino Library; if not, see <http://www.gnu.org/licenses/>.
*/
#pragma once
 
#include <piduino/global.h>
 
namespace Piduino {
 
  class IoMap {
    public:
      IoMap ();
 
      virtual ~IoMap();
 
      bool open (const char *device, size_t size, off_t base = 0);
 
      bool open (off_t base, size_t size);
 
      bool openGpioMem (int gpio_bank, size_t size);
 
      void close();
 
      volatile uint32_t *io (size_t offset = 0) const {
 
        return static_cast<volatile uint32_t *> (_map) + offset;
      }
 
      volatile uint32_t *operator [] (size_t offset) const {
 
        return io (offset);
      }
 
      inline uint32_t read (size_t offset) const {
        return *io (offset);
      }
 
      inline void write (size_t offset, uint32_t value) {
        *io (offset) = value;
      }
 
      inline uint32_t atomicRead (size_t offset) const {
        volatile uint32_t *reg = io (offset);
        return __atomic_load_n (reg, __ATOMIC_SEQ_CST);
      }
 
      inline void atomicWrite (size_t offset, uint32_t value) {
        volatile uint32_t *reg = io (offset);
        __atomic_store_n (reg, value, __ATOMIC_SEQ_CST);
      }
 
      inline bool isOpen() const {
 
        return _fd >= 0;
      }
 
      inline off_t base() const {
        return _base;
      }
 
      inline size_t size() const {
        return _size;
      }
 
      static size_t pageSize();
 
    private:
      off_t _base;  /*< base address of the area */
      size_t _size; /*< size of the area */
      int _fd;      /*< file descriptor for memory area */
      void *_map;   /*< pointer to the area */
  };
}
/* ========================================================================== */