circuitpython/extmod/modmachine.c

/*
 * This file is part of the Micro Python project, http://micropython.org/
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2013, 2014 Damien P. George
 *
 * 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.
 */

#include <stdio.h>
#include <stdint.h>

#include "py/nlr.h"
#include "py/obj.h"
#if MICROPY_PLAT_DEV_MEM
#include <errno.h>
#include <fcntl.h>
#include <sys/mman.h>
#endif

#if MICROPY_PY_MACHINE

#define PAGE_SIZE 4096
#define PAGE_MASK (PAGE_SIZE - 1)

STATIC mp_uint_t get_addr(mp_obj_t addr_o, uint align) {
    mp_uint_t addr = mp_obj_int_get_truncated(addr_o);
    if ((addr & (align - 1)) != 0) {
        nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "address %08x is not aligned to %d bytes", addr, align));
    }
    #if MICROPY_PLAT_DEV_MEM
    {
        // Not thread-safe
        static int fd;
        static mp_uint_t last_base = (mp_uint_t)-1;
        static mp_uint_t map_page;
        if (!fd) {
            fd = open("/dev/mem", O_RDWR | O_SYNC);
            if (fd == -1) {
                nlr_raise(mp_obj_new_exception_arg1(&mp_type_OSError, MP_OBJ_NEW_SMALL_INT(errno)));
            }
        }

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

    return addr;
}

typedef struct _machine_mem_obj_t {
    mp_obj_base_t base;
    unsigned elem_size; // in bytes
} machine_mem_obj_t;

STATIC void machine_mem_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
    (void)kind;
    machine_mem_obj_t *self = self_in;
    mp_printf(print, "<%u-bit memory>", 8 * self->elem_size);
}

STATIC mp_obj_t machine_mem_subscr(mp_obj_t self_in, mp_obj_t index, mp_obj_t value) {
    // TODO support slice index to read/write multiple values at once
    machine_mem_obj_t *self = self_in;
    if (value == MP_OBJ_NULL) {
        // delete
        return MP_OBJ_NULL; // op not supported
    } else if (value == MP_OBJ_SENTINEL) {
        // load
        mp_uint_t addr = get_addr(index, self->elem_size);
        uint32_t val;
        switch (self->elem_size) {
            case 1: val = (*(uint8_t*)addr); break;
            case 2: val = (*(uint16_t*)addr); break;
            default: val = (*(uint32_t*)addr); break;
        }
        return mp_obj_new_int(val);
    } else {
        // store
        mp_uint_t addr = get_addr(index, self->elem_size);
        uint32_t val = mp_obj_get_int(value);
        switch (self->elem_size) {
            case 1: (*(uint8_t*)addr) = val; break;
            case 2: (*(uint16_t*)addr) = val; break;
            default: (*(uint32_t*)addr) = val; break;
        }
        return mp_const_none;
    }
}

STATIC const mp_obj_type_t machine_mem_type = {
    { &mp_type_type },
    .name = MP_QSTR_mem,
    .print = machine_mem_print,
    .subscr = machine_mem_subscr,
};

STATIC const machine_mem_obj_t machine_mem8_obj = {{&machine_mem_type}, 1};
STATIC const machine_mem_obj_t machine_mem16_obj = {{&machine_mem_type}, 2};
STATIC const machine_mem_obj_t machine_mem32_obj = {{&machine_mem_type}, 4};

STATIC const mp_map_elem_t machine_module_globals_table[] = {
    { MP_OBJ_NEW_QSTR(MP_QSTR___name__), MP_OBJ_NEW_QSTR(MP_QSTR_machine) },

    { MP_OBJ_NEW_QSTR(MP_QSTR_mem8), (mp_obj_t)&machine_mem8_obj },
    { MP_OBJ_NEW_QSTR(MP_QSTR_mem16), (mp_obj_t)&machine_mem16_obj },
    { MP_OBJ_NEW_QSTR(MP_QSTR_mem32), (mp_obj_t)&machine_mem32_obj },
};

STATIC MP_DEFINE_CONST_DICT(machine_module_globals, machine_module_globals_table);

const mp_obj_module_t mp_module_machine = {
    .base = { &mp_type_module },
    .name = MP_QSTR_machine,
    .globals = (mp_obj_dict_t*)&machine_module_globals,
};

#endif // MICROPY_PY_MACHINE