AIDL CAN HAL
CAN HAL: now HIDL-free with 100% of your daily value of AIDL.
Bug: 170405615
Test: atest CanControllerAidlTest
Test: manually test slcan and socketcan hardware
Change-Id: I06bbb1379f4385e89757722c0276009b54cc7255
diff --git a/automotive/can/aidl/default/CanBusSlcan.cpp b/automotive/can/aidl/default/CanBusSlcan.cpp
new file mode 100644
index 0000000..6060419
--- /dev/null
+++ b/automotive/can/aidl/default/CanBusSlcan.cpp
@@ -0,0 +1,174 @@
+/*
+ * Copyright 2022, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "CanBusSlcan.h"
+
+#include <android-base/file.h>
+#include <android-base/logging.h>
+#include <libnetdevice/libnetdevice.h>
+
+#include <linux/serial.h>
+#include <linux/tty.h>
+#include <net/if.h>
+#include <termios.h>
+
+#include <map>
+
+namespace aidl::android::hardware::automotive::can {
+
+using namespace std::string_view_literals;
+using namespace ::android::base;
+
+namespace slcanprotocol {
+static constexpr std::string_view kOpenCommand = "O\r"sv;
+static constexpr std::string_view kCloseCommand = "C\r"sv;
+static constexpr int kSlcanDiscipline = N_SLCAN;
+static constexpr int kDefaultDiscipline = N_TTY;
+
+static const std::map<uint32_t, std::string_view> kBitrateCommands = {
+ {10000, "C\rS0\r"sv}, {20000, "C\rS1\r"sv}, {50000, "C\rS2\r"sv},
+ {100000, "C\rS3\r"sv}, {125000, "C\rS4\r"sv}, {250000, "C\rS5\r"sv},
+ {500000, "C\rS6\r"sv}, {800000, "C\rS7\r"sv}, {1000000, "C\rS8\r"sv}};
+} // namespace slcanprotocol
+
+/**
+ * Serial Line CAN constructor
+ * \param string uartName - name of slcan device (e.x. /dev/ttyUSB0)
+ * \param uint32_t bitrate - speed of the CAN bus (125k = MSCAN, 500k = HSCAN)
+ */
+CanBusSlcan::CanBusSlcan(const std::string& uartName, uint32_t bitrate)
+ : CanBus(), mTtyPath(uartName), kBitrate(bitrate) {}
+
+/** helper function to update CanBusSlcan object's iface name */
+Result CanBusSlcan::updateIfaceName(unique_fd& uartFd) {
+ struct ifreq ifrequest = {};
+ /*
+ * Fetching the iface name with an ioctl won't interfere with an open socketCAN iface attached
+ * to this tty. This is important in the event we are trying to register a SLCAN based iface
+ * that has already been configured and brought up.
+ */
+ if (ioctl(uartFd.get(), SIOCGIFNAME, ifrequest.ifr_name) < 0) {
+ PLOG(ERROR) << "Failed to get the name of the created device";
+ return Result::UNKNOWN_ERROR;
+ }
+
+ // Update the CanBus object with name that was assigned to it
+ mIfname = ifrequest.ifr_name;
+ return Result::OK;
+}
+
+Result CanBusSlcan::preUp() {
+ // verify valid bitrate and translate to serial command format
+ std::optional<std::string_view> canBitrateCommand = std::nullopt;
+ if (kBitrate != 0) {
+ const auto lookupIt = slcanprotocol::kBitrateCommands.find(kBitrate);
+ if (lookupIt == slcanprotocol::kBitrateCommands.end()) {
+ return Result::BAD_BITRATE;
+ }
+ canBitrateCommand = lookupIt->second;
+ }
+
+ /* Attempt to open the uart in r/w without blocking or becoming the
+ * controlling terminal */
+ mFd = unique_fd(open(mTtyPath.c_str(), O_RDWR | O_NONBLOCK | O_NOCTTY | O_CLOEXEC));
+ if (!mFd.ok()) {
+ PLOG(ERROR) << "SLCAN Failed to open " << mTtyPath;
+ return Result::BAD_INTERFACE_ID;
+ }
+
+ // If the device is already up, update the iface name in our CanBusSlcan object
+ if (kBitrate == 0) {
+ return updateIfaceName(mFd);
+ }
+
+ // blank terminal settings and pull them from the device
+ struct termios terminalSettings = {};
+ if (tcgetattr(mFd.get(), &terminalSettings) < 0) {
+ PLOG(ERROR) << "Failed to read attrs of" << mTtyPath;
+ return Result::UNKNOWN_ERROR;
+ }
+
+ // change settings to raw mode
+ cfmakeraw(&terminalSettings);
+
+ // disable software flow control
+ terminalSettings.c_iflag &= ~IXOFF;
+ // enable hardware flow control
+ terminalSettings.c_cflag |= CRTSCTS;
+
+ struct serial_struct serialSettings;
+ // get serial settings
+ if (ioctl(mFd.get(), TIOCGSERIAL, &serialSettings) < 0) {
+ PLOG(ERROR) << "Failed to read serial settings from " << mTtyPath;
+ return Result::UNKNOWN_ERROR;
+ }
+ // set low latency mode
+ serialSettings.flags |= ASYNC_LOW_LATENCY;
+ // apply serial settings
+ if (ioctl(mFd.get(), TIOCSSERIAL, &serialSettings) < 0) {
+ PLOG(ERROR) << "Failed to set low latency mode on " << mTtyPath;
+ return Result::UNKNOWN_ERROR;
+ }
+
+ /* TCSADRAIN applies settings after we finish writing the rest of our
+ * changes (as opposed to TCSANOW, which changes immediately) */
+ if (tcsetattr(mFd.get(), TCSADRAIN, &terminalSettings) < 0) {
+ PLOG(ERROR) << "Failed to apply terminal settings to " << mTtyPath;
+ return Result::UNKNOWN_ERROR;
+ }
+
+ // apply speed setting for CAN
+ if (!WriteStringToFd(*canBitrateCommand, mFd)) {
+ PLOG(ERROR) << "Failed to apply CAN bitrate";
+ return Result::UNKNOWN_ERROR;
+ }
+
+ // TODO(b/144775286): set open flag & support listen only
+ if (!WriteStringToFd(slcanprotocol::kOpenCommand, mFd)) {
+ PLOG(ERROR) << "Failed to set open flag";
+ return Result::UNKNOWN_ERROR;
+ }
+
+ // set line discipline to slcan
+ if (ioctl(mFd.get(), TIOCSETD, &slcanprotocol::kSlcanDiscipline) < 0) {
+ PLOG(ERROR) << "Failed to set line discipline to slcan";
+ return Result::UNKNOWN_ERROR;
+ }
+
+ // Update the CanBus object with name that was assigned to it
+ return updateIfaceName(mFd);
+}
+
+bool CanBusSlcan::postDown() {
+ // reset the line discipline to TTY mode
+ if (ioctl(mFd.get(), TIOCSETD, &slcanprotocol::kDefaultDiscipline) < 0) {
+ LOG(ERROR) << "Failed to reset line discipline!";
+ return false;
+ }
+
+ // issue the close command
+ if (!WriteStringToFd(slcanprotocol::kCloseCommand, mFd)) {
+ LOG(ERROR) << "Failed to close tty!";
+ return false;
+ }
+
+ // close our unique_fd
+ mFd.reset();
+
+ return true;
+}
+
+} // namespace aidl::android::hardware::automotive::can