modmachine.c

/*
 * This file is part of the MicroPython project, http://micropython.org/
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2013-2023 Damien P. George
 * Copyright (c) 2015 Paul Sokolovsky
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

// This file is never compiled standalone, it's included directly from
// extmod/modmachine.c via MICROPY_PY_MACHINE_INCLUDEFILE.

#if MICROPY_PLAT_DEV_MEM
#include <errno.h>
#include <fcntl.h>
#include <sys/mman.h>
#define MICROPY_PAGE_SIZE 4096
#define MICROPY_PAGE_MASK (MICROPY_PAGE_SIZE - 1)
#endif

uintptr_t mod_machine_mem_get_addr(mp_obj_t addr_o, uint align) {
    uintptr_t addr = mp_obj_get_int_truncated(addr_o);
    if ((addr & (align - 1)) != 0) {
        mp_raise_msg_varg(&mp_type_ValueError, MP_ERROR_TEXT("address %08x is not aligned to %d bytes"), addr, align);
    }
    #if MICROPY_PLAT_DEV_MEM
    {
        // Not thread-safe
        static int fd;
        static uintptr_t last_base = (uintptr_t)-1;
        static uintptr_t map_page;
        if (!fd) {
            int _fd = open("/dev/mem", O_RDWR | O_SYNC);
            if (_fd == -1) {
                mp_raise_OSError(errno);
            }
            fd = _fd;
        }

        uintptr_t cur_base = addr & ~MICROPY_PAGE_MASK;
        if (cur_base != last_base) {
            map_page = (uintptr_t)mmap(NULL, MICROPY_PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, fd, cur_base);
            last_base = cur_base;
        }
        addr = map_page + (addr & MICROPY_PAGE_MASK);
    }
    #endif

    return addr;
}

static void mp_machine_idle(void) {
    #ifdef MICROPY_UNIX_MACHINE_IDLE
    MICROPY_UNIX_MACHINE_IDLE
    #else
    // Do nothing.
    #endif
}