1 // 2 // Copyright (C) 2015 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 #ifndef TRUNKS_TRUNKS_FTDI_SPI_H_ 18 #define TRUNKS_TRUNKS_FTDI_SPI_H_ 19 20 #include <string> 21 22 #include <base/macros.h> 23 24 #include "trunks/command_transceiver.h" 25 #include "trunks/trunks_export.h" 26 27 #if defined SPI_OVER_FTDI 28 29 #include "trunks/ftdi/mpsse.h" 30 31 namespace trunks { 32 33 // TrunksFtdiSpi is a CommandTransceiver implementation that forwards all 34 // commands to the SPI over FTDI interface directly to a TPM chip. 35 class TRUNKS_EXPORT TrunksFtdiSpi: public CommandTransceiver { 36 public: 37 TrunksFtdiSpi() : mpsse_(NULL), locality_(0) {} 38 ~TrunksFtdiSpi() override; 39 40 // CommandTransceiver methods. 41 bool Init() override; 42 void SendCommand(const std::string& command, 43 const ResponseCallback& callback) override; 44 std::string SendCommandAndWait(const std::string& command) override; 45 46 private: 47 struct mpsse_context* mpsse_; 48 unsigned locality_; // Set at initialization. 49 50 // Read a TPM register into the passed in buffer, where 'bytes' the width of 51 // the register. Return true on success, false on failure. 52 bool FtdiReadReg(unsigned reg_number, size_t bytes, 53 void *buffer); 54 // Write a TPM register from the passed in buffer, where 'bytes' the width of 55 // the register. Return true on success, false on failure. 56 bool FtdiWriteReg(unsigned reg_number, size_t bytes, 57 const void *buffer); 58 // Generate a proper SPI frame for read/write transaction, read_write set to 59 // true for read transactions, the size of the transaction is passed as 60 // 'bytes', addr is the internal TPM address space address (accounting for 61 // locality). 62 // 63 // Note that this function is expected to be called when the SPI bus is idle 64 // (CS deasserted), and will assert the CS before transmitting. 65 void StartTransaction(bool read_write, size_t bytes, unsigned addr); 66 // TPM Status Register is going to be accessed a lot, let's have dedicated 67 // accessors for it, 68 bool ReadTpmSts(uint32_t *status); 69 bool WriteTpmSts(uint32_t status); 70 // Poll status register until the required value is read or the timeout 71 // expires. 72 bool WaitForStatus(uint32_t statusMask, 73 uint32_t statusExpected, int timeout_ms = 10000); 74 // Retrieve current value of the burst count field. 75 size_t GetBurstCount(void); 76 77 DISALLOW_COPY_AND_ASSIGN(TrunksFtdiSpi); 78 }; 79 80 } // namespace trunks 81 82 #else // SPI_OVER_FTDI ^^^^ defined vvvvv NOT defined 83 84 namespace trunks { 85 86 // A plug to support compilations on platforms where FTDI SPI interface is not 87 // available. 88 class TRUNKS_EXPORT TrunksFtdiSpi: public CommandTransceiver { 89 public: 90 TrunksFtdiSpi() {} 91 ~TrunksFtdiSpi() {} 92 93 bool Init() { return false; } 94 void SendCommand(const std::string& command, 95 const ResponseCallback& callback) {} 96 std::string SendCommandAndWait(const std::string& command) { 97 return std::string(""); } 98 }; 99 100 } // namespace trunks 101 102 #endif // SPI_OVER_FTDI ^^^^ NOT defined 103 104 #endif // TRUNKS_TRUNKS_FTDI_SPI_H_ 105
