1 /* 2 * Copyright (C) 2017 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 #ifndef NOS_DEVICE_H 17 #define NOS_DEVICE_H 18 19 #include <stdint.h> 20 21 #ifdef __cplusplus 22 extern "C" { 23 #endif 24 25 /* Max data size for read/write. 26 * Yes, it's a magic number. See b/37675056#comment8. */ 27 #define MAX_DEVICE_TRANSFER 2044 28 29 struct nos_device_ops { 30 /** 31 * Read a datagram from the device. 32 * 33 * Return 0 on success and a negative value on failure. 34 */ 35 int (*read)(void* ctx, uint32_t command, uint8_t *buf, uint32_t len); 36 37 /** 38 * Write a datagram to the device. 39 * 40 * Return 0 on success and a negative value on failure. 41 */ 42 int (*write)(void *ctx, uint32_t command, const uint8_t *buf, uint32_t len); 43 44 /** 45 * Block until an event has happened on the device, or until timed out. 46 * 47 * Values for msecs 48 * <0 wait forever 49 * 0 return immediately (why?) 50 * >0 timeout after this many milliseconds 51 * 52 * Returns: 53 * <0 on error 54 * 0 timed out 55 * >0 interrupt occurred 56 */ 57 int (*wait_for_interrupt)(void *ctx, int msecs); 58 59 /** 60 * Reset the device. 61 * 62 * Return 0 on success and a negative value on failure. 63 */ 64 int (*reset)(void *ctx); 65 66 /** 67 * Close the connection to the device. 68 * 69 * The device must not be used after closing. 70 */ 71 void (*close)(void *ctx); 72 }; 73 74 struct nos_device { 75 void *ctx; 76 struct nos_device_ops ops; 77 }; 78 79 /* 80 * Open a connection to a Nugget device. 81 * 82 * The name parameter identifies which Nugget device to connect to. Passing 83 * NULL connects to the default device. 84 * 85 * This function is implemented by the host specific variants of this library. 86 * 87 * Returns 0 on success or negative on failure. 88 */ 89 int nos_device_open(const char *name, struct nos_device *device); 90 91 #ifdef __cplusplus 92 } 93 #endif 94 95 #endif /* NOS_DEVICE_H */ 96
