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      1 /*
      2  * Copyright (C) 2016 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 <hostIntf.h>
     18 #include <hostIntf_priv.h>
     19 #include <nanohubPacket.h>
     20 #include <spi.h>
     21 
     22 static uint8_t gBusId;
     23 static struct SpiDevice *gSpi;
     24 
     25 static void *gRxBuf;
     26 static size_t gTxSize;
     27 
     28 static struct SpiPacket gPacket;
     29 
     30 static const struct SpiMode gSpiMode = {
     31     .cpol = SPI_CPOL_IDLE_LO,
     32     .cpha = SPI_CPHA_LEADING_EDGE,
     33     .bitsPerWord = 8,
     34     .format = SPI_FORMAT_MSB_FIRST,
     35     .txWord = NANOHUB_PREAMBLE_BYTE,
     36 };
     37 
     38 static void hostIntfSpiRxCallback(void *cookie, int err)
     39 {
     40     struct NanohubPacket *packet = gRxBuf;
     41     HostIntfCommCallbackF callback = cookie;
     42     callback(NANOHUB_PACKET_SIZE(packet->len), err);
     43 }
     44 
     45 static void hostIntfSpiTxCallback(void *cookie, int err)
     46 {
     47     HostIntfCommCallbackF callback = cookie;
     48     callback(gTxSize, err);
     49 }
     50 
     51 static int hostIntfSpiRequest()
     52 {
     53     return spiSlaveRequest(gBusId, &gSpiMode, &gSpi);
     54 }
     55 
     56 static int hostIntfSpiRxPacket(void *rxBuf, size_t rxSize,
     57         HostIntfCommCallbackF callback)
     58 {
     59     int err;
     60 
     61     gPacket.rxBuf = gRxBuf = rxBuf;
     62     gPacket.txBuf = NULL;
     63     gPacket.size = rxSize;
     64 
     65     err = spiSlaveRxTx(gSpi, &gPacket, 1, hostIntfSpiRxCallback, callback);
     66     if (err < 0)
     67         callback(0, err);
     68 
     69     return 0;
     70 }
     71 
     72 static int hostIntfSpiTxPacket(const void *txBuf, size_t txSize,
     73         HostIntfCommCallbackF callback)
     74 {
     75     ((uint8_t *)txBuf)[txSize] = NANOHUB_PREAMBLE_BYTE;
     76     gTxSize = txSize;
     77 
     78     gPacket.rxBuf = NULL;
     79     gPacket.txBuf = txBuf;
     80     gPacket.size = txSize + 1;
     81 
     82     return spiSlaveRxTx(gSpi, &gPacket, 1, hostIntfSpiTxCallback,
     83             callback);
     84 }
     85 
     86 static int hostIntfSpiRelease(void)
     87 {
     88     return spiSlaveRelease(gSpi);
     89 }
     90 
     91 static const struct HostIntfComm gSpiComm = {
     92    .request = hostIntfSpiRequest,
     93    .rxPacket = hostIntfSpiRxPacket,
     94    .txPacket = hostIntfSpiTxPacket,
     95    .release = hostIntfSpiRelease,
     96 };
     97 
     98 const struct HostIntfComm *hostIntfSpiInit(uint8_t busId)
     99 {
    100     gBusId = busId;
    101     return &gSpiComm;
    102 }
    103