chrisweir | cf36cea | 2019-11-08 16:41:02 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2019 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | #include "CanBusSlcan.h" |
| 18 | |
| 19 | #include <android-base/logging.h> |
| 20 | #include <libnetdevice/can.h> |
| 21 | #include <libnetdevice/libnetdevice.h> |
| 22 | |
| 23 | #include <net/if.h> |
| 24 | #include <sys/ioctl.h> |
| 25 | #include <sys/stat.h> |
| 26 | #include <termios.h> |
| 27 | |
Tomasz Wasilczyk | 55f2193 | 2019-12-20 09:20:24 -0800 | [diff] [blame] | 28 | namespace android::hardware::automotive::can::V1_0::implementation { |
chrisweir | cf36cea | 2019-11-08 16:41:02 -0800 | [diff] [blame] | 29 | |
| 30 | namespace slcanprotocol { |
| 31 | static const std::string kOpenCommand = "O\r"; |
| 32 | static const std::string kCloseCommand = "C\r"; |
| 33 | static constexpr int kSlcanDiscipline = N_SLCAN; |
| 34 | static constexpr int kDefaultDiscipline = N_TTY; |
| 35 | |
| 36 | static const std::map<uint32_t, std::string> kBitrateCommands = { |
| 37 | {10000, "C\rS0\r"}, {20000, "C\rS1\r"}, {50000, "C\rS2\r"}, |
| 38 | {100000, "C\rS3\r"}, {125000, "C\rS4\r"}, {250000, "C\rS5\r"}, |
| 39 | {500000, "C\rS6\r"}, {800000, "C\rS7\r"}, {1000000, "C\rS8\r"}}; |
| 40 | } // namespace slcanprotocol |
| 41 | |
| 42 | /** |
| 43 | * Serial Line CAN constructor |
| 44 | * \param string uartName - name of slcan device (e.x. /dev/ttyUSB0) |
| 45 | * \param uint32_t bitrate - speed of the CAN bus (125k = MSCAN, 500k = HSCAN) |
| 46 | */ |
| 47 | CanBusSlcan::CanBusSlcan(const std::string& uartName, uint32_t bitrate) |
| 48 | : CanBus(), mUartName(uartName), kBitrate(bitrate) {} |
| 49 | |
chrisweir | 39187db | 2020-01-06 15:21:07 -0800 | [diff] [blame^] | 50 | /** helper function to update CanBusSlcan object's iface name */ |
| 51 | ICanController::Result CanBusSlcan::updateIfaceName(base::unique_fd& uartFd) { |
| 52 | struct ifreq ifrequest = {}; |
| 53 | /* |
| 54 | * Fetching the iface name with an ioctl won't interfere with an open socketCAN iface attached |
| 55 | * to this tty. This is important in the event we are trying to register a SLCAN based iface |
| 56 | * that has already been configured and brought up. |
| 57 | */ |
| 58 | if (ioctl(uartFd.get(), SIOCGIFNAME, ifrequest.ifr_name) < 0) { |
| 59 | LOG(ERROR) << "Failed to get the name of the created device: " << strerror(errno); |
| 60 | return ICanController::Result::UNKNOWN_ERROR; |
| 61 | } |
| 62 | |
| 63 | // Update the CanBus object with name that was assigned to it |
| 64 | mIfname = ifrequest.ifr_name; |
| 65 | return ICanController::Result::OK; |
| 66 | } |
| 67 | |
chrisweir | cf36cea | 2019-11-08 16:41:02 -0800 | [diff] [blame] | 68 | ICanController::Result CanBusSlcan::preUp() { |
| 69 | // verify valid bitrate and translate to serial command format |
chrisweir | 39187db | 2020-01-06 15:21:07 -0800 | [diff] [blame^] | 70 | std::optional<std::string> canBitrateCommand = std::nullopt; |
| 71 | if (kBitrate != 0) { |
| 72 | const auto lookupIt = slcanprotocol::kBitrateCommands.find(kBitrate); |
| 73 | if (lookupIt == slcanprotocol::kBitrateCommands.end()) { |
| 74 | return ICanController::Result::BAD_BAUDRATE; |
| 75 | } |
| 76 | canBitrateCommand = lookupIt->second; |
chrisweir | cf36cea | 2019-11-08 16:41:02 -0800 | [diff] [blame] | 77 | } |
chrisweir | cf36cea | 2019-11-08 16:41:02 -0800 | [diff] [blame] | 78 | |
| 79 | /* Attempt to open the uart in r/w without blocking or becoming the |
| 80 | * controlling terminal */ |
| 81 | mFd = base::unique_fd(open(mUartName.c_str(), O_RDWR | O_NONBLOCK | O_NOCTTY)); |
| 82 | if (!mFd.ok()) { |
| 83 | LOG(ERROR) << "SLCAN Failed to open " << mUartName << ": " << strerror(errno); |
| 84 | return ICanController::Result::BAD_ADDRESS; |
| 85 | } |
| 86 | |
chrisweir | 39187db | 2020-01-06 15:21:07 -0800 | [diff] [blame^] | 87 | // If the device is already up, update the iface name in our CanBusSlcan object |
| 88 | if (kBitrate == 0) { |
| 89 | return updateIfaceName(mFd); |
| 90 | } |
| 91 | |
chrisweir | cf36cea | 2019-11-08 16:41:02 -0800 | [diff] [blame] | 92 | // blank terminal settings and pull them from the device |
| 93 | struct termios terminalSettings = {}; |
| 94 | if (tcgetattr(mFd.get(), &terminalSettings) < 0) { |
| 95 | LOG(ERROR) << "Failed to read attrs of" << mUartName << ": " << strerror(errno); |
| 96 | return ICanController::Result::UNKNOWN_ERROR; |
| 97 | } |
| 98 | |
| 99 | // change settings to raw mode |
| 100 | cfmakeraw(&terminalSettings); |
| 101 | |
| 102 | // disable software flow control |
| 103 | terminalSettings.c_iflag &= ~IXOFF; |
| 104 | // enable hardware flow control |
| 105 | terminalSettings.c_cflag |= CRTSCTS; |
| 106 | |
| 107 | struct serial_struct serialSettings; |
| 108 | // get serial settings |
| 109 | if (ioctl(mFd.get(), TIOCGSERIAL, &serialSettings) < 0) { |
| 110 | LOG(ERROR) << "Failed to read serial settings from " << mUartName << ": " |
| 111 | << strerror(errno); |
| 112 | return ICanController::Result::UNKNOWN_ERROR; |
| 113 | } |
| 114 | // set low latency mode |
| 115 | serialSettings.flags |= ASYNC_LOW_LATENCY; |
| 116 | // apply serial settings |
| 117 | if (ioctl(mFd.get(), TIOCSSERIAL, &serialSettings) < 0) { |
| 118 | LOG(ERROR) << "Failed to set low latency mode on " << mUartName << ": " << strerror(errno); |
| 119 | return ICanController::Result::UNKNOWN_ERROR; |
| 120 | } |
| 121 | |
| 122 | /* TCSADRAIN applies settings after we finish writing the rest of our |
| 123 | * changes (as opposed to TCSANOW, which changes immediately) */ |
| 124 | if (tcsetattr(mFd.get(), TCSADRAIN, &terminalSettings) < 0) { |
| 125 | LOG(ERROR) << "Failed to apply terminal settings to " << mUartName << ": " |
| 126 | << strerror(errno); |
| 127 | return ICanController::Result::UNKNOWN_ERROR; |
| 128 | } |
| 129 | |
| 130 | // apply speed setting for CAN |
chrisweir | 39187db | 2020-01-06 15:21:07 -0800 | [diff] [blame^] | 131 | if (write(mFd.get(), canBitrateCommand->c_str(), canBitrateCommand->length()) <= 0) { |
chrisweir | cf36cea | 2019-11-08 16:41:02 -0800 | [diff] [blame] | 132 | LOG(ERROR) << "Failed to apply CAN bitrate: " << strerror(errno); |
| 133 | return ICanController::Result::UNKNOWN_ERROR; |
| 134 | } |
| 135 | |
| 136 | // set open flag TODO: also support listen only |
| 137 | if (write(mFd.get(), slcanprotocol::kOpenCommand.c_str(), |
| 138 | slcanprotocol::kOpenCommand.length()) <= 0) { |
| 139 | LOG(ERROR) << "Failed to set open flag: " << strerror(errno); |
| 140 | return ICanController::Result::UNKNOWN_ERROR; |
| 141 | } |
| 142 | |
| 143 | // set line discipline to slcan |
| 144 | if (ioctl(mFd.get(), TIOCSETD, &slcanprotocol::kSlcanDiscipline) < 0) { |
| 145 | LOG(ERROR) << "Failed to set line discipline to slcan: " << strerror(errno); |
| 146 | return ICanController::Result::UNKNOWN_ERROR; |
| 147 | } |
| 148 | |
chrisweir | cf36cea | 2019-11-08 16:41:02 -0800 | [diff] [blame] | 149 | // Update the CanBus object with name that was assigned to it |
chrisweir | 39187db | 2020-01-06 15:21:07 -0800 | [diff] [blame^] | 150 | return updateIfaceName(mFd); |
chrisweir | cf36cea | 2019-11-08 16:41:02 -0800 | [diff] [blame] | 151 | } |
| 152 | |
| 153 | bool CanBusSlcan::postDown() { |
| 154 | // reset the line discipline to TTY mode |
| 155 | if (ioctl(mFd.get(), TIOCSETD, &slcanprotocol::kDefaultDiscipline) < 0) { |
| 156 | LOG(ERROR) << "Failed to reset line discipline!"; |
| 157 | return false; |
| 158 | } |
| 159 | |
| 160 | // issue the close command |
| 161 | if (write(mFd.get(), slcanprotocol::kCloseCommand.c_str(), |
| 162 | slcanprotocol::kCloseCommand.length()) <= 0) { |
| 163 | LOG(ERROR) << "Failed to close tty!"; |
| 164 | return false; |
| 165 | } |
| 166 | |
| 167 | // close our unique_fd |
| 168 | mFd.reset(); |
| 169 | |
| 170 | return true; |
| 171 | } |
| 172 | |
Tomasz Wasilczyk | 55f2193 | 2019-12-20 09:20:24 -0800 | [diff] [blame] | 173 | } // namespace android::hardware::automotive::can::V1_0::implementation |