circuitpython/devices/ble_hci/common-hal/_bleio/Characteristic.c

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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) Dan Halbert for Adafruit Industries
* Copyright (c) 2018 Artur Pacholec
*
* 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 "py/runtime.h"
#include "shared-bindings/_bleio/__init__.h"
#include "shared-bindings/_bleio/Characteristic.h"
#include "shared-bindings/_bleio/Descriptor.h"
#include "shared-bindings/_bleio/Service.h"
#include "common-hal/_bleio/Adapter.h"
#include "common-hal/_bleio/bonding.h"
STATIC uint16_t characteristic_get_cccd(uint16_t cccd_handle, uint16_t conn_handle) {
uint16_t cccd;
ble_gatts_value_t value = {
.p_value = (uint8_t*) &cccd,
.len = 2,
};
const uint32_t err_code = sd_ble_gatts_value_get(conn_handle, cccd_handle, &value);
if (err_code == BLE_ERROR_GATTS_SYS_ATTR_MISSING) {
// CCCD is not set, so say that neither Notify nor Indicate is enabled.
cccd = 0;
} else {
check_nrf_error(err_code);
}
return cccd;
}
STATIC void characteristic_gatts_notify_indicate(uint16_t handle, uint16_t conn_handle, mp_buffer_info_t *bufinfo, uint16_t hvx_type) {
uint16_t hvx_len = bufinfo->len;
ble_gatts_hvx_params_t hvx_params = {
.handle = handle,
.type = hvx_type,
.offset = 0,
.p_len = &hvx_len,
.p_data = bufinfo->buf,
};
while (1) {
const uint32_t err_code = sd_ble_gatts_hvx(conn_handle, &hvx_params);
if (err_code == NRF_SUCCESS) {
break;
}
// TX buffer is full
// We could wait for an event indicating the write is complete, but just retrying is easier.
if (err_code == NRF_ERROR_RESOURCES) {
RUN_BACKGROUND_TASKS;
continue;
}
// Some real error has occurred.
check_nrf_error(err_code);
}
}
void common_hal_bleio_characteristic_construct(bleio_characteristic_obj_t *self, bleio_service_obj_t *service, uint16_t handle, bleio_uuid_obj_t *uuid, bleio_characteristic_properties_t props, bleio_attribute_security_mode_t read_perm, bleio_attribute_security_mode_t write_perm, mp_int_t max_length, bool fixed_length, mp_buffer_info_t *initial_value_bufinfo) {
self->service = service;
self->uuid = uuid;
self->handle = BLE_GATT_HANDLE_INVALID;
self->props = props;
self->read_perm = read_perm;
self->write_perm = write_perm;
self->descriptor_list = NULL;
const mp_int_t max_length_max = fixed_length ? BLE_GATTS_FIX_ATTR_LEN_MAX : BLE_GATTS_VAR_ATTR_LEN_MAX;
if (max_length < 0 || max_length > max_length_max) {
mp_raise_ValueError_varg(translate("max_length must be 0-%d when fixed_length is %s"),
max_length_max, fixed_length ? "True" : "False");
}
self->max_length = max_length;
self->fixed_length = fixed_length;
if (service->is_remote) {
self->handle = handle;
} else {
common_hal_bleio_service_add_characteristic(self->service, self, initial_value_bufinfo);
}
if (initial_value_bufinfo != NULL) {
common_hal_bleio_characteristic_set_value(self, initial_value_bufinfo);
}
}
bleio_descriptor_obj_t *common_hal_bleio_characteristic_get_descriptor_list(bleio_characteristic_obj_t *self) {
return self->descriptor_list;
}
bleio_service_obj_t *common_hal_bleio_characteristic_get_service(bleio_characteristic_obj_t *self) {
return self->service;
}
size_t common_hal_bleio_characteristic_get_value(bleio_characteristic_obj_t *self, uint8_t* buf, size_t len) {
// Do GATT operations only if this characteristic has been added to a registered service.
if (self->handle != BLE_GATT_HANDLE_INVALID) {
uint16_t conn_handle = bleio_connection_get_conn_handle(self->service->connection);
if (common_hal_bleio_service_get_is_remote(self->service)) {
// self->value is set by evt handler.
return common_hal_bleio_gattc_read(self->handle, conn_handle, buf, len);
} else {
// conn_handle is ignored for non-system attributes.
return common_hal_bleio_gatts_read(self->handle, conn_handle, buf, len);
}
}
return 0;
}
void common_hal_bleio_characteristic_set_value(bleio_characteristic_obj_t *self, mp_buffer_info_t *bufinfo) {
if (self->fixed_length && bufinfo->len != self->max_length) {
mp_raise_ValueError(translate("Value length != required fixed length"));
}
if (bufinfo->len > self->max_length) {
mp_raise_ValueError(translate("Value length > max_length"));
}
// Do GATT operations only if this characteristic has been added to a registered service.
if (self->handle != BLE_GATT_HANDLE_INVALID) {
if (common_hal_bleio_service_get_is_remote(self->service)) {
uint16_t conn_handle = bleio_connection_get_conn_handle(self->service->connection);
// Last argument is true if write-no-reponse desired.
common_hal_bleio_gattc_write(self->handle, conn_handle, bufinfo,
(self->props & CHAR_PROP_WRITE_NO_RESPONSE));
} else {
// Always write the value locally even if no connections are active.
// conn_handle is ignored for non-system attributes, so we use BLE_CONN_HANDLE_INVALID.
common_hal_bleio_gatts_write(self->handle, BLE_CONN_HANDLE_INVALID, bufinfo);
// Check to see if we need to notify or indicate any active connections.
for (size_t i = 0; i < BLEIO_TOTAL_CONNECTION_COUNT; i++) {
bleio_connection_internal_t *connection = &bleio_connections[i];
uint16_t conn_handle = connection->conn_handle;
if (connection->conn_handle == BLE_CONN_HANDLE_INVALID) {
continue;
}
uint16_t cccd = 0;
const bool notify = self->props & CHAR_PROP_NOTIFY;
const bool indicate = self->props & CHAR_PROP_INDICATE;
if (notify | indicate) {
cccd = characteristic_get_cccd(self->cccd_handle, conn_handle);
}
// It's possible that both notify and indicate are set.
if (notify && (cccd & BLE_GATT_HVX_NOTIFICATION)) {
characteristic_gatts_notify_indicate(self->handle, conn_handle, bufinfo, BLE_GATT_HVX_NOTIFICATION);
}
if (indicate && (cccd & BLE_GATT_HVX_INDICATION)) {
characteristic_gatts_notify_indicate(self->handle, conn_handle, bufinfo, BLE_GATT_HVX_INDICATION);
}
}
}
}
}
bleio_uuid_obj_t *common_hal_bleio_characteristic_get_uuid(bleio_characteristic_obj_t *self) {
return self->uuid;
}
bleio_characteristic_properties_t common_hal_bleio_characteristic_get_properties(bleio_characteristic_obj_t *self) {
return self->props;
}
void common_hal_bleio_characteristic_add_descriptor(bleio_characteristic_obj_t *self, bleio_descriptor_obj_t *descriptor) {
ble_uuid_t desc_uuid;
bleio_uuid_convert_to_nrf_ble_uuid(descriptor->uuid, &desc_uuid);
ble_gatts_attr_md_t desc_attr_md = {
// Data passed is not in a permanent location and should be copied.
.vloc = BLE_GATTS_VLOC_STACK,
.vlen = !descriptor->fixed_length,
};
bleio_attribute_gatts_set_security_mode(&desc_attr_md.read_perm, descriptor->read_perm);
bleio_attribute_gatts_set_security_mode(&desc_attr_md.write_perm, descriptor->write_perm);
mp_buffer_info_t desc_value_bufinfo;
mp_get_buffer_raise(descriptor->value, &desc_value_bufinfo, MP_BUFFER_READ);
ble_gatts_attr_t desc_attr = {
.p_uuid = &desc_uuid,
.p_attr_md = &desc_attr_md,
.init_len = desc_value_bufinfo.len,
.p_value = desc_value_bufinfo.buf,
.init_offs = 0,
.max_len = descriptor->max_length,
};
check_nrf_error(sd_ble_gatts_descriptor_add(self->handle, &desc_attr, &descriptor->handle));
descriptor->next = self->descriptor_list;
self->descriptor_list = descriptor;
}
void common_hal_bleio_characteristic_set_cccd(bleio_characteristic_obj_t *self, bool notify, bool indicate) {
if (self->cccd_handle == BLE_GATT_HANDLE_INVALID) {
mp_raise_bleio_BluetoothError(translate("No CCCD for this Characteristic"));
}
if (!common_hal_bleio_service_get_is_remote(self->service)) {
mp_raise_bleio_RoleError(translate("Can't set CCCD on local Characteristic"));
}
const uint16_t conn_handle = bleio_connection_get_conn_handle(self->service->connection);
common_hal_bleio_check_connected(conn_handle);
uint16_t cccd_value =
(notify ? BLE_GATT_HVX_NOTIFICATION : 0) |
(indicate ? BLE_GATT_HVX_INDICATION : 0);
ble_gattc_write_params_t write_params = {
.write_op = BLE_GATT_OP_WRITE_REQ,
.handle = self->cccd_handle,
.p_value = (uint8_t *) &cccd_value,
.len = 2,
};
while (1) {
uint32_t err_code = sd_ble_gattc_write(conn_handle, &write_params);
if (err_code == NRF_SUCCESS) {
break;
}
// Write with response will return NRF_ERROR_BUSY if the response has not been received.
// Write without reponse will return NRF_ERROR_RESOURCES if too many writes are pending.
if (err_code == NRF_ERROR_BUSY || err_code == NRF_ERROR_RESOURCES) {
// We could wait for an event indicating the write is complete, but just retrying is easier.
RUN_BACKGROUND_TASKS;
continue;
}
// Some real error occurred.
check_nrf_error(err_code);
}
}