summaryrefslogtreecommitdiff
path: root/platforms/chibios/drivers/serial_usart.c
blob: c05003b12ee7bdb977dae1ee8bd5aac1a56c4be4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
/* Copyright 2021 QMK
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "serial_usart.h"

#if defined(SERIAL_USART_CONFIG)
static SerialConfig serial_config = SERIAL_USART_CONFIG;
#else
static SerialConfig serial_config = {
    .speed = (SERIAL_USART_SPEED), /* speed - mandatory */
    .cr1   = (SERIAL_USART_CR1),
    .cr2   = (SERIAL_USART_CR2),
#    if !defined(SERIAL_USART_FULL_DUPLEX)
    .cr3   = ((SERIAL_USART_CR3) | USART_CR3_HDSEL) /* activate half-duplex mode */
#    else
    .cr3 = (SERIAL_USART_CR3)
#    endif
};
#endif

static SerialDriver* serial_driver = &SERIAL_USART_DRIVER;

static inline bool react_to_transactions(void);
static inline bool __attribute__((nonnull)) receive(uint8_t* destination, const size_t size);
static inline bool __attribute__((nonnull)) send(const uint8_t* source, const size_t size);
static inline int  initiate_transaction(uint8_t sstd_index);
static inline void usart_clear(void);

/**
 * @brief Clear the receive input queue.
 */
static inline void usart_clear(void) {
    osalSysLock();
    bool volatile queue_not_empty = !iqIsEmptyI(&serial_driver->iqueue);
    osalSysUnlock();

    while (queue_not_empty) {
        osalSysLock();
        /* Hard reset the input queue. */
        iqResetI(&serial_driver->iqueue);
        osalSysUnlock();
        /* Allow pending interrupts to preempt.
         * Do not merge the lock/unlock blocks into one
         * or the code will not work properly.
         * The empty read adds a tiny amount of delay. */
        (void)queue_not_empty;
        osalSysLock();
        queue_not_empty = !iqIsEmptyI(&serial_driver->iqueue);
        osalSysUnlock();
    }
}

/**
 * @brief Blocking send of buffer with timeout.
 *
 * @return true Send success.
 * @return false Send failed.
 */
static inline bool send(const uint8_t* source, const size_t size) {
    bool success = (size_t)sdWriteTimeout(serial_driver, source, size, TIME_MS2I(SERIAL_USART_TIMEOUT)) == size;

#if !defined(SERIAL_USART_FULL_DUPLEX)
    if (success) {
        /* Half duplex fills the input queue with the data we wrote - just throw it away.
           Under the right circumstances (e.g. bad cables paired with high baud rates)
           less bytes can be present in the input queue, therefore a timeout is needed. */
        uint8_t dump[size];
        return receive(dump, size);
    }
#endif

    return success;
}

/**
 * @brief  Blocking receive of size * bytes with timeout.
 *
 * @return true Receive success.
 * @return false Receive failed.
 */
static inline bool receive(uint8_t* destination, const size_t size) {
    bool success = (size_t)sdReadTimeout(serial_driver, destination, size, TIME_MS2I(SERIAL_USART_TIMEOUT)) == size;
    return success;
}

#if !defined(SERIAL_USART_FULL_DUPLEX)

/**
 * @brief Initiate pins for USART peripheral. Half-duplex configuration.
 */
__attribute__((weak)) void usart_init(void) {
#    if defined(MCU_STM32)
#        if defined(USE_GPIOV1)
    palSetLineMode(SERIAL_USART_TX_PIN, PAL_MODE_ALTERNATE_OPENDRAIN);
#        else
    palSetLineMode(SERIAL_USART_TX_PIN, PAL_MODE_ALTERNATE(SERIAL_USART_TX_PAL_MODE) | PAL_MODE_OUTPUT_OPENDRAIN);
#        endif

#        if defined(USART_REMAP)
    USART_REMAP;
#        endif
#    else
#        pragma message "usart_init: MCU Familiy not supported by default, please supply your own init code by implementing usart_init() in your keyboard files."
#    endif
}

#else

/**
 * @brief Initiate pins for USART peripheral. Full-duplex configuration.
 */
__attribute__((weak)) void usart_init(void) {
#    if defined(MCU_STM32)
#        if defined(USE_GPIOV1)
    palSetLineMode(SERIAL_USART_TX_PIN, PAL_MODE_ALTERNATE_PUSHPULL);
    palSetLineMode(SERIAL_USART_RX_PIN, PAL_MODE_INPUT);
#        else
    palSetLineMode(SERIAL_USART_TX_PIN, PAL_MODE_ALTERNATE(SERIAL_USART_TX_PAL_MODE) | PAL_MODE_OUTPUT_PUSHPULL | PAL_OUTPUT_SPEED_HIGHEST);
    palSetLineMode(SERIAL_USART_RX_PIN, PAL_MODE_ALTERNATE(SERIAL_USART_RX_PAL_MODE) | PAL_MODE_OUTPUT_PUSHPULL | PAL_OUTPUT_SPEED_HIGHEST);
#        endif

#        if defined(USART_REMAP)
    USART_REMAP;
#        endif
#    else
#        pragma message "usart_init: MCU Familiy not supported by default, please supply your own init code by implementing usart_init() in your keyboard files."
#    endif
}

#endif

/**
 * @brief Overridable master specific initializations.
 */
__attribute__((weak, nonnull)) void usart_master_init(SerialDriver** driver) {
    (void)driver;
    usart_init();
}

/**
 * @brief Overridable slave specific initializations.
 */
__attribute__((weak, nonnull)) void usart_slave_init(SerialDriver** driver) {
    (void)driver;
    usart_init();
}

/**
 * @brief This thread runs on the slave and responds to transactions initiated
 * by the master.
 */
static THD_WORKING_AREA(waSlaveThread, 1024);
static THD_FUNCTION(SlaveThread, arg) {
    (void)arg;
    chRegSetThreadName("usart_tx_rx");

    while (true) {
        if (!react_to_transactions()) {
            /* Clear the receive queue, to start with a clean slate.
             * Parts of failed transactions or spurious bytes could still be in it. */
            usart_clear();
        }
    }
}

/**
 * @brief Slave specific initializations.
 */
void soft_serial_target_init(void) {
    usart_slave_init(&serial_driver);

    sdStart(serial_driver, &serial_config);

    /* Start transport thread. */
    chThdCreateStatic(waSlaveThread, sizeof(waSlaveThread), HIGHPRIO, SlaveThread, NULL);
}

/**
 * @brief React to transactions started by the master.
 */
static inline bool react_to_transactions(void) {
    /* Wait until there is a transaction for us. */
    uint8_t sstd_index = (uint8_t)sdGet(serial_driver);

    /* Sanity check that we are actually responding to a valid transaction. */
    if (sstd_index >= NUM_TOTAL_TRANSACTIONS) {
        return false;
    }

    split_transaction_desc_t* trans = &split_transaction_table[sstd_index];

    /* Send back the handshake which is XORed as a simple checksum,
     to signal that the slave is ready to receive possible transaction buffers  */
    sstd_index ^= HANDSHAKE_MAGIC;
    if (!send(&sstd_index, sizeof(sstd_index))) {
        *trans->status = TRANSACTION_DATA_ERROR;
        return false;
    }

    /* Receive transaction buffer from the master. If this transaction requires it.*/
    if (trans->initiator2target_buffer_size) {
        if (!receive(split_trans_initiator2target_buffer(trans), trans->initiator2target_buffer_size)) {
            *trans->status = TRANSACTION_DATA_ERROR;
            return false;
        }
    }

    /* Allow any slave processing to occur. */
    if (trans->slave_callback) {
        trans->slave_callback(trans->initiator2target_buffer_size, split_trans_initiator2target_buffer(trans), trans->initiator2target_buffer_size, split_trans_target2initiator_buffer(trans));
    }

    /* Send transaction buffer to the master. If this transaction requires it. */
    if (trans->target2initiator_buffer_size) {
        if (!send(split_trans_target2initiator_buffer(trans), trans->target2initiator_buffer_size)) {
            *trans->status = TRANSACTION_DATA_ERROR;
            return false;
        }
    }

    *trans->status = TRANSACTION_ACCEPTED;
    return true;
}

/**
 * @brief Master specific initializations.
 */
void soft_serial_initiator_init(void) {
    usart_master_init(&serial_driver);

#if defined(MCU_STM32) && defined(SERIAL_USART_PIN_SWAP)
    serial_config.cr2 |= USART_CR2_SWAP;  // master has swapped TX/RX pins
#endif

    sdStart(serial_driver, &serial_config);
}

/**
 * @brief Start transaction from the master half to the slave half.
 *
 * @param index Transaction Table index of the transaction to start.
 * @return int TRANSACTION_NO_RESPONSE in case of Timeout.
 *             TRANSACTION_TYPE_ERROR in case of invalid transaction index.
 *             TRANSACTION_END in case of success.
 */
int soft_serial_transaction(int index) {
    /* Clear the receive queue, to start with a clean slate.
     * Parts of failed transactions or spurious bytes could still be in it. */
    usart_clear();
    return initiate_transaction((uint8_t)index);
}

/**
 * @brief Initiate transaction to slave half.
 */
static inline int initiate_transaction(uint8_t sstd_index) {
    /* Sanity check that we are actually starting a valid transaction. */
    if (sstd_index >= NUM_TOTAL_TRANSACTIONS) {
        dprintln("USART: Illegal transaction Id.");
        return TRANSACTION_TYPE_ERROR;
    }

    split_transaction_desc_t* trans = &split_transaction_table[sstd_index];

    /* Transaction is not registered. Abort. */
    if (!trans->status) {
        dprintln("USART: Transaction not registered.");
        return TRANSACTION_TYPE_ERROR;
    }

    /* Send transaction table index to the slave, which doubles as basic handshake token. */
    if (!send(&sstd_index, sizeof(sstd_index))) {
        dprintln("USART: Send Handshake failed.");
        return TRANSACTION_TYPE_ERROR;
    }

    uint8_t sstd_index_shake = 0xFF;

    /* Which we always read back first so that we can error out correctly.
     *   - due to the half duplex limitations on return codes, we always have to read *something*.
     *   - without the read, write only transactions *always* succeed, even during the boot process where the slave is not ready.
     */
    if (!receive(&sstd_index_shake, sizeof(sstd_index_shake)) || (sstd_index_shake != (sstd_index ^ HANDSHAKE_MAGIC))) {
        dprintln("USART: Handshake failed.");
        return TRANSACTION_NO_RESPONSE;
    }

    /* Send transaction buffer to the slave. If this transaction requires it. */
    if (trans->initiator2target_buffer_size) {
        if (!send(split_trans_initiator2target_buffer(trans), trans->initiator2target_buffer_size)) {
            dprintln("USART: Send failed.");
            return TRANSACTION_NO_RESPONSE;
        }
    }

    /* Receive transaction buffer from the slave. If this transaction requires it. */
    if (trans->target2initiator_buffer_size) {
        if (!receive(split_trans_target2initiator_buffer(trans), trans->target2initiator_buffer_size)) {
            dprintln("USART: Receive failed.");
            return TRANSACTION_NO_RESPONSE;
        }
    }

    return TRANSACTION_END;
}