Keyboard: Helix serial improvements (#3608)

* add change_reciver2sender()/change_sender2reciver()

This is a change to improve readability.

* txled, rxled off in matrix_init()

* add serial_send_packet() / serial_recive_packet()

This is a change to reduce object size.

* add serial_low() at ISR() top

* add __attribute__((always_inline)) to some functions

* modify serial_send_packet()/serial_recive_packet()

A little, object size reduction.
A little, speedup.

* add debug code to helix/serial.c

* Adjust sampling timing of serial signal being received

* add split_scomm.c/split_scomm.h and change serial.c/serial.h

serial.c was divided into 2 layers, split_scom.c and serial.c.
The upper layer split_scomm.c is called from matrix.c.
The lower layer serial.c accesses the hardware.

* add split_scomm.c/split_scomm.h into helix/rev1

* reduce object size helix/rev2/matrix.c

* remove checksum check, add parity check

* force occur parity error for test

* parity test ok. remove test code

* change some comment & add skip code when buffer_size == 0

* serial.c: multiple types of transaction support

Add 4 bits transaction-type field at packet top.
Select Transaction Descriptor Table entry by transaction-type.

* helix serial master-slave transaction optimize

Using multi-type transaction feature of serial.c, communication contents between master slaves were optimized.

* add debug code for retry

* add comment into each config.h

* fix ISR status drop

* add a debug macro 'debug_retry_chg()'

* reduce led_test size

* remove debug code from helix/serial.c and etc.

* helix:five_rows change TAPPING_TERM value 140

* Improved compatibility with let's split of serial.c. Finish helix/serial.c improvement.

- The difference with the original let's split's serial.c
  - It's high-speed about 4 times.
  - Stable bi-directional data transfer. (Helix need master to slave transfer)
  - serial.h was divided 2 files, serial_config.h and sereial.h
  - With multiple types of transaction support, communication contents can be optimized. (NEW flexible API)

- USE OLD Simple APIs (compatible with let's split serial.c)
  - files :
    - serial_config.h -- hardware configuration (need include by config.h)
    - serial.c/serial.h -- serial communication

- USE NEW flexible APIs. (Support multi-type transaction function.)
  serial.c was divided into 2 layers, split_scom.c and serial.c.
  The upper layer split_scomm.c is called from matrix.c.
  The lower layer serial.c accesses the hardware.
  - files
    - split_scomm.c -- communication buffer is defined in here. call by matrix.c.
    - split_scomm.h -- buffer size is defined in here. include by matrix.c, split_util.c
    - serial_config.h -- hardware configuration (need include by config.h)
      To use the NEW API, specify #define SERIAL_USE_MULTI_TRANSACTION
    - serial.c/serial.h -- serial communication lower layer

- NEW APIs for serial.c / serial.h (The lower layer)
  // Soft Serial Transaction Descriptor
  typedef struct _SSTD_t  {
      uint8_t *status;
      uint8_t initiator2target_buffer_size;
      uint8_t *initiator2target_buffer;
      uint8_t target2initiator_buffer_size;
      uint8_t *target2initiator_buffer;
  } SSTD_t;

  // initiator is transaction start side
  void soft_serial_initiator_init(SSTD_t *sstd_table);
  // target is interrupt accept side
  void soft_serial_target_init(SSTD_t *sstd_table);
  int soft_serial_transaction(int sstd_index);
  int soft_serial_get_and_clean_target_status(int sstd_index);

- NEW APIs for split_scomm.c / split_scomm.h (The upper layer)
   move from old serial.c the following buffer and functions
     serial_slave_buffer[]
     serial_master_buffer[]
     void serial_master_init(void)
     void serial_slave_init(void)
     int serial_update_buffers(void)
   define SERIAL_xxxxx_BUFFER_LENGTH move from serial_config.h to split_scomm.h

keyboards/helix/rev2/matrix.c

@@ -20,6 +20,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 #include <stdint.h>
 #include <stdbool.h>
+#include <string.h>
 #include <avr/io.h>
 #include <avr/wdt.h>
 #include <avr/interrupt.h>
@@ -34,7 +35,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #ifdef USE_MATRIX_I2C
 #  include "i2c.h"
 #else // USE_SERIAL
-#  include "serial.h"
+#  include "split_scomm.h"
 #endif
 
 #ifndef DEBOUNCE
@@ -102,6 +103,8 @@ void matrix_init(void)
     init_cols();
 
     TX_RX_LED_INIT;
+    TXLED0;
+    RXLED0;
 
     // initialize matrix state: all keys off
     for (uint8_t i=0; i < MATRIX_ROWS; i++) {
@@ -178,17 +181,20 @@ i2c_error: // the cable is disconnceted, or something else went wrong
 
 #else // USE_SERIAL
 
-int serial_transaction(void) {
+int serial_transaction(int master_changed) {
     int slaveOffset = (isLeftHand) ? (ROWS_PER_HAND) : 0;
+#ifdef SERIAL_USE_MULTI_TRANSACTION
+    int ret=serial_update_buffers(master_changed);
+#else
     int ret=serial_update_buffers();
+#endif
     if (ret ) {
-        if(ret==2)RXLED1;
+        if(ret==2) RXLED1;
         return 1;
     }
-RXLED0;
-    for (int i = 0; i < ROWS_PER_HAND; ++i) {
-        matrix[slaveOffset+i] = serial_slave_buffer[i];
-    }
+    RXLED0;
+    memcpy(&matrix[slaveOffset],
+        (void *)serial_slave_buffer, sizeof(serial_slave_buffer));
     return 0;
 }
 #endif
@@ -199,19 +205,9 @@ uint8_t matrix_scan(void)
         matrix_master_scan();
     }else{
         matrix_slave_scan();
-
-//        if(serial_slave_DATA_CORRUPT()){
-//          TXLED0;
-          int offset = (isLeftHand) ? ROWS_PER_HAND : 0;
-
-          for (int i = 0; i < ROWS_PER_HAND; ++i) {
-              matrix[offset+i] = serial_master_buffer[i];
-          }
-
-//        }else{
-//          TXLED1;
-//        }
-
+        int offset = (isLeftHand) ? ROWS_PER_HAND : 0;
+        memcpy(&matrix[offset],
+               (void *)serial_master_buffer, sizeof(serial_master_buffer));
         matrix_scan_quantum();
     }
     return 1;
@@ -221,6 +217,7 @@ uint8_t matrix_scan(void)
 uint8_t matrix_master_scan(void) {
 
     int ret = _matrix_scan();
+    int mchanged = 1;
 
 #ifndef KEYBOARD_helix_rev1
     int offset = (isLeftHand) ? 0 : ROWS_PER_HAND;
@@ -231,16 +228,19 @@ uint8_t matrix_master_scan(void) {
 //        i2c_slave_buffer[i] = matrix[offset+i];
 //    }
 #else // USE_SERIAL
-    for (int i = 0; i < ROWS_PER_HAND; ++i) {
-        serial_master_buffer[i] = matrix[offset+i];
-    }
+  #ifdef SERIAL_USE_MULTI_TRANSACTION
+    mchanged = memcmp((void *)serial_master_buffer,
+		      &matrix[offset], sizeof(serial_master_buffer));
+  #endif
+    memcpy((void *)serial_master_buffer,
+	   &matrix[offset], sizeof(serial_master_buffer));
 #endif
 #endif
 
 #ifdef USE_MATRIX_I2C
     if( i2c_transaction() ) {
 #else // USE_SERIAL
-    if( serial_transaction() ) {
+    if( serial_transaction(mchanged) ) {
 #endif
         // turn on the indicator led when halves are disconnected
         TXLED1;
@@ -274,9 +274,19 @@ void matrix_slave_scan(void) {
         i2c_slave_buffer[i] = matrix[offset+i];
     }
 #else // USE_SERIAL
+  #ifdef SERIAL_USE_MULTI_TRANSACTION
+    int change = 0;
+  #endif
     for (int i = 0; i < ROWS_PER_HAND; ++i) {
+  #ifdef SERIAL_USE_MULTI_TRANSACTION
+        if( serial_slave_buffer[i] != matrix[offset+i] )
+	    change = 1;
+  #endif
         serial_slave_buffer[i] = matrix[offset+i];
     }
+  #ifdef SERIAL_USE_MULTI_TRANSACTION
+    slave_buffer_change_count += change;
+  #endif
 #endif
 }