zephyr: Implement block device protocol via zephyr flash map api.

Introduces a new zephyr.FlashArea class that uses the zephyr flash map
api to implement the uos.AbstractBlockDev protocol. The flash driver is
enabled on the frdm_k64f board, reel_board, and rv32m1_vega_ri5cy board.

The standard and extended block device protocols are both supported,
therefore this class can be used with file systems like littlefs which
require the extended interface.

ports/zephyr/modzephyr.c

@@ -95,6 +95,9 @@ STATIC const mp_rom_map_elem_t mp_module_time_globals_table[] = {
     #ifdef CONFIG_DISK_ACCESS
     { MP_ROM_QSTR(MP_QSTR_DiskAccess), MP_ROM_PTR(&zephyr_disk_access_type) },
     #endif
+    #ifdef CONFIG_FLASH_MAP
+    { MP_ROM_QSTR(MP_QSTR_FlashArea), MP_ROM_PTR(&zephyr_flash_area_type) },
+    #endif
 };
 
 STATIC MP_DEFINE_CONST_DICT(mp_module_time_globals, mp_module_time_globals_table);

ports/zephyr/modzephyr.h

@@ -33,4 +33,8 @@
 extern const mp_obj_type_t zephyr_disk_access_type;
 #endif
 
+#ifdef CONFIG_FLASH_MAP
+extern const mp_obj_type_t zephyr_flash_area_type;
+#endif
+
 #endif // MICROPY_INCLUDED_ZEPHYR_MODZEPHYR_H

ports/zephyr/prj_frdm_k64f.conf

@@ -8,3 +8,8 @@ CONFIG_I2C=y
 CONFIG_FXOS8700=y
 CONFIG_FXOS8700_MODE_HYBRID=y
 CONFIG_FXOS8700_TEMP=y
+
+# Flash drivers
+CONFIG_FLASH=y
+CONFIG_FLASH_MAP=y
+CONFIG_MPU_ALLOW_FLASH_WRITE=y

ports/zephyr/prj_reel_board.conf

@@ -0,0 +1,4 @@
+# Flash drivers
+CONFIG_FLASH=y
+CONFIG_FLASH_MAP=y
+CONFIG_MPU_ALLOW_FLASH_WRITE=y

ports/zephyr/prj_rv32m1_vega_ri5cy.conf

@@ -0,0 +1,3 @@
+# Flash drivers
+CONFIG_FLASH=y
+CONFIG_FLASH_MAP=y

ports/zephyr/zephyr_storage.c

@@ -35,6 +35,10 @@
 #include <disk/disk_access.h>
 #endif
 
+#ifdef CONFIG_FLASH_MAP
+#include <storage/flash_map.h>
+#endif
+
 #ifdef CONFIG_DISK_ACCESS
 typedef struct _zephyr_disk_access_obj_t {
     mp_obj_base_t base;
@@ -133,3 +137,125 @@ const mp_obj_type_t zephyr_disk_access_type = {
     .locals_dict = (mp_obj_dict_t*)&zephyr_disk_access_locals_dict,
 };
 #endif // CONFIG_DISK_ACCESS
+
+#ifdef CONFIG_FLASH_MAP
+const mp_obj_type_t zephyr_flash_area_type;
+
+typedef struct _zephyr_flash_area_obj_t {
+    mp_obj_base_t base;
+    const struct flash_area *area;
+    int block_size;
+    int block_count;
+    u8_t id;
+} zephyr_flash_area_obj_t;
+
+STATIC void zephyr_flash_area_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
+    zephyr_flash_area_obj_t *self = self_in;
+    mp_printf(print, "FlashArea(%d)", self->id);
+}
+
+STATIC mp_obj_t zephyr_flash_area_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *args) {
+    mp_arg_check_num(n_args, n_kw, 2, 2, false);
+    zephyr_flash_area_obj_t *self = m_new_obj(zephyr_flash_area_obj_t);
+    self->base.type = type;
+    self->id = mp_obj_get_int(args[0]);
+    self->block_size = mp_obj_get_int(args[1]);
+
+    if (self->block_size <= 0) {
+        mp_raise_ValueError("invalid block size");
+    }
+
+    if (flash_area_open(self->id, &self->area) != 0) {
+        mp_raise_ValueError("unable to open flash area");
+    }
+
+    self->block_count = self->area->fa_size / self->block_size;
+
+    return MP_OBJ_FROM_PTR(self);
+}
+
+STATIC mp_obj_t zephyr_flash_area_readblocks(size_t n_args, const mp_obj_t *args) {
+    zephyr_flash_area_obj_t *self = MP_OBJ_TO_PTR(args[0]);
+    uint32_t block_num = mp_obj_get_int(args[1]);
+    off_t offset = block_num * self->block_size;
+    mp_buffer_info_t bufinfo;
+    int ret;
+
+    if (n_args >= 4) {
+        offset += mp_obj_get_int(args[3]);
+    }
+
+    mp_get_buffer_raise(args[2], &bufinfo, MP_BUFFER_WRITE);
+    ret = flash_area_read(self->area, offset, bufinfo.buf, bufinfo.len);
+    return MP_OBJ_NEW_SMALL_INT(ret);
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(zephyr_flash_area_readblocks_obj, 3, 4, zephyr_flash_area_readblocks);
+
+STATIC mp_obj_t zephyr_flash_area_writeblocks(size_t n_args, const mp_obj_t *args) {
+    zephyr_flash_area_obj_t *self = MP_OBJ_TO_PTR(args[0]);
+    uint32_t block_num = mp_obj_get_int(args[1]);
+    off_t offset = block_num * self->block_size;
+    mp_buffer_info_t bufinfo;
+    int ret;
+
+    if (n_args == 3) {
+        ret = flash_area_erase(self->area, offset, self->block_size);
+        if (ret) {
+            return MP_OBJ_NEW_SMALL_INT(ret);
+        }
+    } else {
+        offset += mp_obj_get_int(args[3]);
+    }
+
+    mp_get_buffer_raise(args[2], &bufinfo, MP_BUFFER_READ);
+    ret = flash_area_write(self->area, offset, bufinfo.buf, bufinfo.len);
+    return MP_OBJ_NEW_SMALL_INT(ret);
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(zephyr_flash_area_writeblocks_obj, 3, 4, zephyr_flash_area_writeblocks);
+
+STATIC mp_obj_t zephyr_flash_area_ioctl(mp_obj_t self_in, mp_obj_t cmd_in, mp_obj_t arg_in) {
+    zephyr_flash_area_obj_t *self = self_in;
+    mp_int_t cmd = mp_obj_get_int(cmd_in);
+    mp_int_t block_num = mp_obj_get_int(arg_in);
+    int ret;
+
+    switch (cmd) {
+        case MP_BLOCKDEV_IOCTL_INIT:
+        case MP_BLOCKDEV_IOCTL_DEINIT:
+        case MP_BLOCKDEV_IOCTL_SYNC:
+            return MP_OBJ_NEW_SMALL_INT(0);
+
+        case MP_BLOCKDEV_IOCTL_BLOCK_COUNT:
+            return MP_OBJ_NEW_SMALL_INT(self->block_count);
+
+        case MP_BLOCKDEV_IOCTL_BLOCK_SIZE:
+            return MP_OBJ_NEW_SMALL_INT(self->block_size);
+
+        case MP_BLOCKDEV_IOCTL_BLOCK_ERASE:
+            ret = flash_area_erase(self->area, block_num * self->block_size, self->block_size);
+            return MP_OBJ_NEW_SMALL_INT(ret);
+
+        default:
+            return MP_OBJ_NEW_SMALL_INT(-1);
+    }
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_3(zephyr_flash_area_ioctl_obj, zephyr_flash_area_ioctl);
+
+STATIC const mp_rom_map_elem_t zephyr_flash_area_locals_dict_table[] = {
+    { MP_ROM_QSTR(MP_QSTR_readblocks), MP_ROM_PTR(&zephyr_flash_area_readblocks_obj) },
+    { MP_ROM_QSTR(MP_QSTR_writeblocks), MP_ROM_PTR(&zephyr_flash_area_writeblocks_obj) },
+    { MP_ROM_QSTR(MP_QSTR_ioctl), MP_ROM_PTR(&zephyr_flash_area_ioctl_obj) },
+    #ifdef DT_FLASH_AREA_STORAGE_ID
+    { MP_ROM_QSTR(MP_QSTR_STORAGE), MP_ROM_INT(DT_FLASH_AREA_STORAGE_ID) },
+    #endif
+};
+STATIC MP_DEFINE_CONST_DICT(zephyr_flash_area_locals_dict, zephyr_flash_area_locals_dict_table);
+
+const mp_obj_type_t zephyr_flash_area_type = {
+    { &mp_type_type },
+    .name = MP_QSTR_FlashArea,
+    .print = zephyr_flash_area_print,
+    .make_new = zephyr_flash_area_make_new,
+    .locals_dict = (mp_obj_dict_t*)&zephyr_flash_area_locals_dict,
+};
+#endif // CONFIG_FLASH_MAP