From c4b8b36950a0b936c4b699afaecd77cdc642d471 Mon Sep 17 00:00:00 2001
From: tmk <hasu@tmk-kbd.com>
Date: Wed, 4 Dec 2019 11:34:05 +0900
Subject: [PATCH] core: Add IBM PC Keyboard protocol support

---
 tmk_core/protocol/ibmpc.c | 264 ++++++++++++++++++++++++++++++++++++++
 tmk_core/protocol/ibmpc.h | 199 ++++++++++++++++++++++++++++
 2 files changed, 463 insertions(+)
 create mode 100644 tmk_core/protocol/ibmpc.c
 create mode 100644 tmk_core/protocol/ibmpc.h

diff --git a/tmk_core/protocol/ibmpc.c b/tmk_core/protocol/ibmpc.c
new file mode 100644
index 00000000..e65ac461
--- /dev/null
+++ b/tmk_core/protocol/ibmpc.c
@@ -0,0 +1,264 @@
+/*
+Copyright 2010,2011,2012,2013,2019 Jun WAKO <wakojun@gmail.com>
+
+This software is licensed with a Modified BSD License.
+All of this is supposed to be Free Software, Open Source, DFSG-free,
+GPL-compatible, and OK to use in both free and proprietary applications.
+Additions and corrections to this file are welcome.
+
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+* Redistributions of source code must retain the above copyright
+  notice, this list of conditions and the following disclaimer.
+
+* Redistributions in binary form must reproduce the above copyright
+  notice, this list of conditions and the following disclaimer in
+  the documentation and/or other materials provided with the
+  distribution.
+
+* Neither the name of the copyright holders nor the names of
+  contributors may be used to endorse or promote products derived
+  from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+*/
+
+/*
+ * IBM PC keyboard protocol
+ */
+
+#include <stdbool.h>
+#include <avr/interrupt.h>
+#include "ringbuf.h"
+#include "ibmpc.h"
+#include "debug.h"
+#include "timer.h"
+#include "wait.h"
+
+
+#define WAIT(stat, us, err) do { \
+    if (!wait_##stat(us)) { \
+        ibmpc_error = err; \
+        goto ERROR; \
+    } \
+} while (0)
+
+
+#define BUF_SIZE 16
+static uint8_t buf[BUF_SIZE];
+static ringbuf_t rb = {
+    .buffer = buf,
+    .head = 0,
+    .tail = 0,
+    .size_mask = BUF_SIZE - 1
+};
+
+volatile uint8_t ibmpc_protocol = IBMPC_PROTOCOL_AT;
+volatile uint8_t ibmpc_error = IBMPC_ERR_NONE;
+
+void ibmpc_host_init(void)
+{
+    clock_init();
+    data_init();
+    idle();
+    IBMPC_INT_INIT();
+    IBMPC_INT_ON();
+    // POR(150-2000ms) plus BAT(300-500ms) may take 2.5sec([3]p.20)
+    //wait_ms(2500);
+}
+
+int16_t ibmpc_host_send(uint8_t data)
+{
+    bool parity = true;
+    ibmpc_error = IBMPC_ERR_NONE;
+
+    if (ibmpc_protocol == IBMPC_PROTOCOL_XT) return -1;
+
+    dprintf("w%02X ", data);
+
+    IBMPC_INT_OFF();
+
+    /* terminate a transmission if we have */
+    inhibit();
+    wait_us(100); // 100us [4]p.13, [5]p.50
+
+    /* 'Request to Send' and Start bit */
+    data_lo();
+    clock_hi();
+    WAIT(clock_lo, 10000, 1);   // 10ms [5]p.50
+
+    /* Data bit[2-9] */
+    for (uint8_t i = 0; i < 8; i++) {
+        wait_us(15);
+        if (data&(1<<i)) {
+            parity = !parity;
+            data_hi();
+        } else {
+            data_lo();
+        }
+        WAIT(clock_hi, 50, 2);
+        WAIT(clock_lo, 50, 3);
+    }
+
+    /* Parity bit */
+    wait_us(15);
+    if (parity) { data_hi(); } else { data_lo(); }
+    WAIT(clock_hi, 50, 4);
+    WAIT(clock_lo, 50, 5);
+
+    /* Stop bit */
+    wait_us(15);
+    data_hi();
+
+    /* Ack */
+    WAIT(data_lo, 50, 6);
+    WAIT(clock_lo, 50, 7);
+
+    /* wait for idle state */
+    WAIT(clock_hi, 50, 8);
+    WAIT(data_hi, 50, 9);
+
+    idle();
+    IBMPC_INT_ON();
+    return ibmpc_host_recv_response();
+ERROR:
+    ibmpc_error |= IBMPC_ERR_SEND;
+    idle();
+    IBMPC_INT_ON();
+    return -1;
+}
+
+int16_t ibmpc_host_recv_response(void)
+{
+    // Command may take 25ms/20ms at most([5]p.46, [3]p.21)
+    uint8_t retry = 25;
+    while (retry-- && ringbuf_is_empty(&rb)) {
+        wait_ms(1);
+    }
+    int16_t data = ringbuf_get(&rb);
+    if (data != -1) dprintf("r%02X ", data);
+    return data;
+}
+
+/* get data received by interrupt */
+int16_t ibmpc_host_recv(void)
+{
+    int16_t data = ringbuf_get(&rb);
+    if (data != -1) dprintf("r%02X ", data);
+    return data;
+}
+
+ISR(IBMPC_INT_VECT)
+{
+    static uint16_t last_time = 0;
+    static enum {
+        START,
+        BIT0, BIT1, BIT2, BIT3, BIT4, BIT5, BIT6, BIT7,
+        PARITY,
+        STOP,
+    } state = START;
+    static uint8_t data = 0;
+    static uint8_t parity = 1;
+
+    // return unless falling edge
+    if (clock_in()) {
+        return;
+    }
+
+    // Reset state when taking more than 1ms
+    if (last_time && timer_elapsed(last_time) > 10) {
+        ibmpc_error = IBMPC_ERR_TIMEOUT | IBMPC_ERR_RECV | state;
+        state = START;
+        data = 0;
+        parity = 1;
+    }
+    last_time = timer_read();
+
+    switch (state) {
+        case START:
+            if (ibmpc_protocol == IBMPC_PROTOCOL_XT) {
+                // ignore start(0) bit
+                if (!data_in()) return;
+            } else {
+                if (data_in())
+                    goto ERROR;
+            }
+        case BIT0:
+        case BIT1:
+        case BIT2:
+        case BIT3:
+        case BIT4:
+        case BIT5:
+        case BIT6:
+        case BIT7:
+            data >>= 1;
+            if (data_in()) {
+                data |= 0x80;
+                parity++;
+            }
+            if (state == BIT7 && ibmpc_protocol == IBMPC_PROTOCOL_XT) {
+                if (!ringbuf_put(&rb, data)) {
+                    ibmpc_error = IBMPC_ERR_FULL;
+                    goto ERROR;
+                }
+                ibmpc_error = IBMPC_ERR_NONE;
+                goto DONE;
+            }
+            break;
+        case PARITY:
+            if (data_in()) {
+                if (!(parity & 0x01))
+                    goto ERROR;
+            } else {
+                if (parity & 0x01)
+                    goto ERROR;
+            }
+            break;
+        case STOP:
+            if (!data_in())
+                goto ERROR;
+            if (!ringbuf_put(&rb, data)) {
+                ibmpc_error = IBMPC_ERR_FULL;
+                goto ERROR;
+            }
+            ibmpc_error = IBMPC_ERR_NONE;
+            goto DONE;
+            break;
+        default:
+            goto ERROR;
+    }
+    goto NEXT;
+
+ERROR:
+    ibmpc_error |= state;
+    ibmpc_error |= IBMPC_ERR_RECV;
+    ringbuf_reset(&rb);
+DONE:
+    last_time = 0;
+    state = START;
+    data = 0;
+    parity = 1;
+    return;
+NEXT:
+    state++;
+    return;
+}
+
+/* send LED state to keyboard */
+void ibmpc_host_set_led(uint8_t led)
+{
+    ibmpc_host_send(0xED);
+    ibmpc_host_send(led);
+}
diff --git a/tmk_core/protocol/ibmpc.h b/tmk_core/protocol/ibmpc.h
new file mode 100644
index 00000000..47e71e27
--- /dev/null
+++ b/tmk_core/protocol/ibmpc.h
@@ -0,0 +1,199 @@
+/*
+Copyright 2010,2011,2012,2013,2019 Jun WAKO <wakojun@gmail.com>
+
+This software is licensed with a Modified BSD License.
+All of this is supposed to be Free Software, Open Source, DFSG-free,
+GPL-compatible, and OK to use in both free and proprietary applications.
+Additions and corrections to this file are welcome.
+
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+* Redistributions of source code must retain the above copyright
+  notice, this list of conditions and the following disclaimer.
+
+* Redistributions in binary form must reproduce the above copyright
+  notice, this list of conditions and the following disclaimer in
+  the documentation and/or other materials provided with the
+  distribution.
+
+* Neither the name of the copyright holders nor the names of
+  contributors may be used to endorse or promote products derived
+  from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+*/
+
+#ifndef IBMPC_H
+#define IBMPC_H
+
+#include <stdbool.h>
+#include "wait.h"
+#include "print.h"
+
+/*
+ * IBM PC keyboard protocol
+ *
+ * PS/2 Resources
+ * --------------
+ * [1] The PS/2 Mouse/Keyboard Protocol
+ * http://www.computer-engineering.org/ps2protocol/
+ * Concise and thorough primer of PS/2 protocol.
+ *
+ * [2] Keyboard and Auxiliary Device Controller
+ * http://www.mcamafia.de/pdf/ibm_hitrc07.pdf
+ * Signal Timing and Format
+ *
+ * [3] Keyboards(101- and 102-key)
+ * http://www.mcamafia.de/pdf/ibm_hitrc11.pdf
+ * Keyboard Layout, Scan Code Set, POR, and Commands.
+ *
+ * [4] PS/2 Reference Manuals
+ * http://www.mcamafia.de/pdf/ibm_hitrc07.pdf
+ * Collection of IBM Personal System/2 documents.
+ *
+ * [5] TrackPoint Engineering Specifications for version 3E
+ * https://web.archive.org/web/20100526161812/http://wwwcssrv.almaden.ibm.com/trackpoint/download.html
+ */
+#define IBMPC_ACK         0xFA
+#define IBMPC_RESEND      0xFE
+#define IBMPC_SET_LED     0xED
+
+#define IBMPC_PROTOCOL_AT   0
+#define IBMPC_PROTOCOL_XT   1
+
+// TODO: error numbers
+#define IBMPC_ERR_NONE        0
+#define IBMPC_ERR_RECV        0x00
+#define IBMPC_ERR_SEND        0x10
+#define IBMPC_ERR_TIMEOUT     0x20
+#define IBMPC_ERR_FULL        0x40
+
+#define IBMPC_LED_SCROLL_LOCK 0
+#define IBMPC_LED_NUM_LOCK    1
+#define IBMPC_LED_CAPS_LOCK   2
+
+
+extern volatile uint8_t ibmpc_protocol;
+extern volatile uint8_t ibmpc_error;
+
+void ibmpc_host_init(void);
+int16_t ibmpc_host_send(uint8_t data);
+int16_t ibmpc_host_recv_response(void);
+int16_t ibmpc_host_recv(void);
+void ibmpc_host_set_led(uint8_t usb_led);
+
+
+/*--------------------------------------------------------------------
+ * static functions
+ *------------------------------------------------------------------*/
+#if defined(__AVR__)
+/*
+ * Clock
+ */
+static inline void clock_init(void)
+{
+    IBMPC_CLOCK_PORT &= ~(1<<IBMPC_CLOCK_BIT);
+    IBMPC_CLOCK_DDR  |=  (1<<IBMPC_CLOCK_BIT);
+}
+
+static inline void clock_lo(void)
+{
+    IBMPC_CLOCK_PORT &= ~(1<<IBMPC_CLOCK_BIT);
+    IBMPC_CLOCK_DDR  |=  (1<<IBMPC_CLOCK_BIT);
+}
+
+static inline void clock_hi(void)
+{
+    /* input with pull up */
+    IBMPC_CLOCK_DDR  &= ~(1<<IBMPC_CLOCK_BIT);
+    IBMPC_CLOCK_PORT |=  (1<<IBMPC_CLOCK_BIT);
+}
+
+static inline bool clock_in(void)
+{
+    IBMPC_CLOCK_DDR  &= ~(1<<IBMPC_CLOCK_BIT);
+    IBMPC_CLOCK_PORT |=  (1<<IBMPC_CLOCK_BIT);
+    wait_us(1);
+    return IBMPC_CLOCK_PIN&(1<<IBMPC_CLOCK_BIT);
+}
+
+/*
+ * Data
+ */
+static inline void data_init(void)
+{
+    IBMPC_DATA_DDR  &= ~(1<<IBMPC_DATA_BIT);
+    IBMPC_DATA_PORT |=  (1<<IBMPC_DATA_BIT);
+}
+
+static inline void data_lo(void)
+{
+    IBMPC_DATA_PORT &= ~(1<<IBMPC_DATA_BIT);
+    IBMPC_DATA_DDR  |=  (1<<IBMPC_DATA_BIT);
+}
+
+static inline void data_hi(void)
+{
+    /* input with pull up */
+    IBMPC_DATA_DDR  &= ~(1<<IBMPC_DATA_BIT);
+    IBMPC_DATA_PORT |=  (1<<IBMPC_DATA_BIT);
+}
+
+static inline bool data_in(void)
+{
+    IBMPC_DATA_DDR  &= ~(1<<IBMPC_DATA_BIT);
+    IBMPC_DATA_PORT |=  (1<<IBMPC_DATA_BIT);
+    wait_us(1);
+    return IBMPC_DATA_PIN&(1<<IBMPC_DATA_BIT);
+}
+#endif
+
+
+static inline uint16_t wait_clock_lo(uint16_t us)
+{
+    while (clock_in()  && us) { asm(""); wait_us(1); us--; }
+    return us;
+}
+static inline uint16_t wait_clock_hi(uint16_t us)
+{
+    while (!clock_in() && us) { asm(""); wait_us(1); us--; }
+    return us;
+}
+static inline uint16_t wait_data_lo(uint16_t us)
+{
+    while (data_in() && us)  { asm(""); wait_us(1); us--; }
+    return us;
+}
+static inline uint16_t wait_data_hi(uint16_t us)
+{
+    while (!data_in() && us)  { asm(""); wait_us(1); us--; }
+    return us;
+}
+
+/* idle state that device can send */
+static inline void idle(void)
+{
+    clock_hi();
+    data_hi();
+}
+
+/* inhibit device to send */
+static inline void inhibit(void)
+{
+    clock_lo();
+    data_hi();
+}
+
+#endif
-- 
2.45.2