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[canbus] Keep constant send payloads in shared flash tables (#20309)

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This commit is contained in:
J. Nick Koston
2026-10-08 11:14:02 -04:00
committed by GitHub
parent 9066ad6cd0
commit 79813a1eac
6 changed files with 100 additions and 53 deletions
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esphome/components/canbus/__init__.py
+24 -22
View File
@@ -144,20 +144,26 @@ async def register_canbus(var: MockObj, config: ConfigType) -> None:
# Actions
CANBUS_SEND_ACTION_SCHEMA = cv.maybe_simple_value(
{
cv.GenerateID(CONF_CANBUS_ID): cv.use_id(CanbusComponent),
cv.Optional(CONF_CAN_ID): cv.int_range(min=0, max=0x1FFFFFFF),
cv.Optional(CONF_USE_EXTENDED_ID, default=False): cv.boolean,
cv.Optional(CONF_REMOTE_TRANSMISSION_REQUEST, default=False): cv.boolean,
# One classic CAN frame
cv.Required(CONF_DATA): cv.templatable(
cv.All(validate_raw_data, cv.Length(max=8))
),
},
validate_id,
key=CONF_DATA,
)
@automation.register_action(
"canbus.send",
canbus_ns.class_("CanbusSendAction", automation.Action),
cv.maybe_simple_value(
{
cv.GenerateID(CONF_CANBUS_ID): cv.use_id(CanbusComponent),
cv.Optional(CONF_CAN_ID): cv.int_range(min=0, max=0x1FFFFFFF),
cv.Optional(CONF_USE_EXTENDED_ID, default=False): cv.boolean,
cv.Optional(CONF_REMOTE_TRANSMISSION_REQUEST, default=False): cv.boolean,
cv.Required(CONF_DATA): cv.templatable(validate_raw_data),
},
validate_id,
key=CONF_DATA,
),
CANBUS_SEND_ACTION_SCHEMA,
synchronous=True,
)
async def canbus_action_to_code(
@@ -177,15 +183,11 @@ async def canbus_action_to_code(
var.set_remote_transmission_request(config[CONF_REMOTE_TRANSMISSION_REQUEST])
)
data = config[CONF_DATA]
if cg.is_template(data):
templ = await cg.templatable(data, args, cg.std_vector.template(cg.uint8))
cg.add(var.set_data_template(templ))
else:
if isinstance(data, bytes):
data = [int(x) for x in data]
# Generate static array in flash to avoid RAM copy
arr_id = ID(f"{action_id}_data", is_declaration=True, type=cg.uint8)
arr = cg.static_const_array(arr_id, cg.ArrayInitializer(*data))
cg.add(var.set_data_static(arr, len(data)))
await automation.templatable_bytes(
config[CONF_DATA],
args,
var.set_data_template,
var.set_data_static,
"canbus_data",
)
return var
esphome/components/canbus/canbus.cpp
+3 -4
View File
@@ -22,10 +22,11 @@ void Canbus::dump_config() {
}
canbus::Error Canbus::send_data(uint32_t can_id, bool use_extended_id, bool remote_transmission_request,
const std::vector<uint8_t> &data) {
const uint8_t *data, size_t len) {
struct CanFrame can_message;
uint8_t size = static_cast<uint8_t>(data.size());
// Clamp before narrowing, so a lambda payload of 256 bytes or more cannot wrap to a short length
const uint8_t size = static_cast<uint8_t>(std::min<size_t>(len, CAN_MAX_DATA_LENGTH));
if (use_extended_id) {
ESP_LOGD(TAG, "send extended id=0x%08" PRIx32 " rtr=%s size=%d", can_id, TRUEFALSE(remote_transmission_request),
size);
@@ -33,8 +34,6 @@ canbus::Error Canbus::send_data(uint32_t can_id, bool use_extended_id, bool remo
ESP_LOGD(TAG, "send standard id=0x%03" PRIx32 " rtr=%s size=%d", can_id, TRUEFALSE(remote_transmission_request),
size);
}
if (size > CAN_MAX_DATA_LENGTH)
size = CAN_MAX_DATA_LENGTH;
can_message.can_data_length_code = size;
can_message.can_id = can_id;
can_message.use_extended_id = use_extended_id;
esphome/components/canbus/canbus.h
+11 -27
View File
@@ -69,8 +69,12 @@ class Canbus : public Component {
float get_setup_priority() const override { return setup_priority::HARDWARE; }
void loop() override;
canbus::Error send_data(uint32_t can_id, bool use_extended_id, bool remote_transmission_request, const uint8_t *data,
size_t len);
canbus::Error send_data(uint32_t can_id, bool use_extended_id, bool remote_transmission_request,
const std::vector<uint8_t> &data);
const std::vector<uint8_t> &data) {
return this->send_data(can_id, use_extended_id, remote_transmission_request, data.data(), data.size());
}
canbus::Error send_data(uint32_t can_id, bool use_extended_id, const std::vector<uint8_t> &data) {
// for backwards compatibility only
return this->send_data(can_id, use_extended_id, false, data);
@@ -107,18 +111,7 @@ class Canbus : public Component {
};
template<typename... Ts> class CanbusSendAction final : public Action<Ts...>, public Parented<Canbus> {
public:
void set_data_template(std::vector<uint8_t> (*func)(Ts...)) {
// Stateless lambdas (generated by ESPHome) implicitly convert to function pointers
this->data_.func = func;
this->len_ = -1; // Sentinel value indicates template mode
}
// Store pointer to static data in flash (no RAM copy)
void set_data_static(const uint8_t *data, size_t len) {
this->data_.data = data;
this->len_ = len; // Length >= 0 indicates static mode
}
TEMPLATABLE_BYTES(data)
void set_can_id(uint32_t can_id) { this->can_id_ = can_id; }
@@ -132,26 +125,17 @@ template<typename... Ts> class CanbusSendAction final : public Action<Ts...>, pu
auto can_id = this->can_id_.has_value() ? *this->can_id_ : this->parent_->can_id_;
auto use_extended_id =
this->use_extended_id_.has_value() ? *this->use_extended_id_ : this->parent_->use_extended_id_;
std::vector<uint8_t> data;
if (this->len_ >= 0) {
// Static mode: copy from flash to vector
data.assign(this->data_.data, this->data_.data + this->len_);
} else {
// Template mode: call function
data = this->data_.func(x...);
}
this->parent_->send_data(can_id, use_extended_id, this->remote_transmission_request_, data);
this->data_.template visit<CAN_MAX_DATA_LENGTH>(
[&](const uint8_t *data, size_t len) {
this->parent_->send_data(can_id, use_extended_id, this->remote_transmission_request_, data, len);
},
x...);
}
protected:
optional<uint32_t> can_id_{};
optional<bool> use_extended_id_{};
bool remote_transmission_request_{false};
ssize_t len_{-1}; // -1 = template mode, >=0 = static mode with length
union Data {
std::vector<uint8_t> (*func)(Ts...); // Function pointer (stateless lambdas)
const uint8_t *data; // Pointer to static data in flash
} data_;
};
class CanbusTrigger final : public Trigger<std::vector<uint8_t>, uint32_t, bool>, public Component {
tests/component_tests/canbus/__init__.py
View File
tests/component_tests/canbus/config/payload_tables.yaml
+21
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@@ -0,0 +1,21 @@
---
esphome:
name: test
on_boot:
then:
- canbus.send: [0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08]
- canbus.send:
can_id: 0x100
data: [0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08]
- canbus.send: !lambda return {0x09};
esp32:
board: esp32dev
canbus:
- platform: esp32_can
id: can_bus
rx_pin: 4
tx_pin: 5
can_id: 4
bit_rate: 50kbps
tests/component_tests/canbus/test_canbus_payload_tables.py
+41
View File
@@ -0,0 +1,41 @@
"""Tests for canbus constant payloads in shared PROGMEM tables."""
from collections.abc import Callable
from pathlib import Path
import re
import pytest
from esphome.components.canbus import CANBUS_SEND_ACTION_SCHEMA
import esphome.config_validation as cv
def test_constant_payloads_share_progmem_tables(
generate_main: Callable[[str | Path], str],
component_config_path: Callable[[str], Path],
) -> None:
"""Equal send payloads share one table; lambdas stay templates."""
main_cpp = generate_main(component_config_path("payload_tables.yaml"))
tables = re.findall(
r"static constexpr uint8_t (\w+)\[\] PROGMEM = (\{[^}]*\});", main_cpp
)
assert [v for _, v in tables] == [
"{0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08}"
]
assert main_cpp.count(f"set_data_static({tables[0][0]}, 8);") == 2
assert "set_data_template(" in main_cpp
@pytest.mark.parametrize("size", [8, 9])
@pytest.mark.parametrize("make", [lambda n: [0x01] * n, lambda n: "a" * n])
def test_send_one_frame_limit(
size: int, make: Callable[[int], list[int] | str]
) -> None:
"""Payloads up to one 8 byte CAN frame are accepted, longer ones rejected."""
config = {"canbus_id": "can_bus", "data": make(size)}
if size <= 8:
assert len(CANBUS_SEND_ACTION_SCHEMA(config)["data"]) == size
else:
with pytest.raises(cv.Invalid, match="at most 8"):
CANBUS_SEND_ACTION_SCHEMA(config)