From a074364c3731d66b56d988c8a6c960a83ea0e0a1 Mon Sep 17 00:00:00 2001
From: tmk <hasu@tmk-kbd.com>
Date: Fri, 10 Apr 2015 01:32:04 +0900
Subject: Squashed 'tmk_core/' content from commit 05caacc

git-subtree-dir: tmk_core
git-subtree-split: 05caaccec92694bb24c8c3c3a9940b96efd4605c
---
 protocol/ps2_usart.c | 223 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 223 insertions(+)
 create mode 100644 protocol/ps2_usart.c

(limited to 'protocol/ps2_usart.c')

diff --git a/protocol/ps2_usart.c b/protocol/ps2_usart.c
new file mode 100644
index 0000000000..6936ca7b88
--- /dev/null
+++ b/protocol/ps2_usart.c
@@ -0,0 +1,223 @@
+/*
+Copyright 2010,2011,2012,2013 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.
+*/
+
+/*
+ * PS/2 protocol USART version
+ */
+
+#include <stdbool.h>
+#include <avr/interrupt.h>
+#include <util/delay.h>
+#include "ps2.h"
+#include "ps2_io.h"
+#include "print.h"
+
+
+#define WAIT(stat, us, err) do { \
+    if (!wait_##stat(us)) { \
+        ps2_error = err; \
+        goto ERROR; \
+    } \
+} while (0)
+
+
+uint8_t ps2_error = PS2_ERR_NONE;
+
+
+static inline uint8_t pbuf_dequeue(void);
+static inline void pbuf_enqueue(uint8_t data);
+static inline bool pbuf_has_data(void);
+static inline void pbuf_clear(void);
+
+
+void ps2_host_init(void)
+{
+    idle(); // without this many USART errors occur when cable is disconnected
+    PS2_USART_INIT();
+    PS2_USART_RX_INT_ON();
+    // POR(150-2000ms) plus BAT(300-500ms) may take 2.5sec([3]p.20)
+    //_delay_ms(2500);
+}
+
+uint8_t ps2_host_send(uint8_t data)
+{
+    bool parity = true;
+    ps2_error = PS2_ERR_NONE;
+
+    PS2_USART_OFF();
+
+    /* terminate a transmission if we have */
+    inhibit();
+    _delay_us(100); // [4]p.13
+
+    /* 'Request to Send' and Start bit */
+    data_lo();
+    clock_hi();
+    WAIT(clock_lo, 10000, 10);   // 10ms [5]p.50
+
+    /* Data bit[2-9] */
+    for (uint8_t i = 0; i < 8; i++) {
+        _delay_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 */
+    _delay_us(15);
+    if (parity) { data_hi(); } else { data_lo(); }
+    WAIT(clock_hi, 50, 4);
+    WAIT(clock_lo, 50, 5);
+
+    /* Stop bit */
+    _delay_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();
+    PS2_USART_INIT();
+    PS2_USART_RX_INT_ON();
+    return ps2_host_recv_response();
+ERROR:
+    idle();
+    PS2_USART_INIT();
+    PS2_USART_RX_INT_ON();
+    return 0;
+}
+
+uint8_t ps2_host_recv_response(void)
+{
+    // Command may take 25ms/20ms at most([5]p.46, [3]p.21)
+    uint8_t retry = 25;
+    while (retry-- && !pbuf_has_data()) {
+        _delay_ms(1);
+    }
+    return pbuf_dequeue();
+}
+
+uint8_t ps2_host_recv(void)
+{
+    if (pbuf_has_data()) {
+        ps2_error = PS2_ERR_NONE;
+        return pbuf_dequeue();
+    } else {
+        ps2_error = PS2_ERR_NODATA;
+        return 0;
+    }
+}
+
+ISR(PS2_USART_RX_VECT)
+{
+    // TODO: request RESEND when error occurs?
+    uint8_t error = PS2_USART_ERROR;    // USART error should be read before data
+    uint8_t data = PS2_USART_RX_DATA;
+    if (!error) {
+        pbuf_enqueue(data);
+    } else {
+        xprintf("PS2 USART error: %02X data: %02X\n", error, data);
+    }
+}
+
+/* send LED state to keyboard */
+void ps2_host_set_led(uint8_t led)
+{
+    ps2_host_send(0xED);
+    ps2_host_send(led);
+}
+
+
+/*--------------------------------------------------------------------
+ * Ring buffer to store scan codes from keyboard
+ *------------------------------------------------------------------*/
+#define PBUF_SIZE 32
+static uint8_t pbuf[PBUF_SIZE];
+static uint8_t pbuf_head = 0;
+static uint8_t pbuf_tail = 0;
+static inline void pbuf_enqueue(uint8_t data)
+{
+    uint8_t sreg = SREG;
+    cli();
+    uint8_t next = (pbuf_head + 1) % PBUF_SIZE;
+    if (next != pbuf_tail) {
+        pbuf[pbuf_head] = data;
+        pbuf_head = next;
+    } else {
+        print("pbuf: full\n");
+    }
+    SREG = sreg;
+}
+static inline uint8_t pbuf_dequeue(void)
+{
+    uint8_t val = 0;
+
+    uint8_t sreg = SREG;
+    cli();
+    if (pbuf_head != pbuf_tail) {
+        val = pbuf[pbuf_tail];
+        pbuf_tail = (pbuf_tail + 1) % PBUF_SIZE;
+    }
+    SREG = sreg;
+
+    return val;
+}
+static inline bool pbuf_has_data(void)
+{
+    uint8_t sreg = SREG;
+    cli();
+    bool has_data = (pbuf_head != pbuf_tail);
+    SREG = sreg;
+    return has_data;
+}
+static inline void pbuf_clear(void)
+{
+    uint8_t sreg = SREG;
+    cli();
+    pbuf_head = pbuf_tail = 0;
+    SREG = sreg;
+}
-- 
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