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authortmk <nobody@nowhere>2012-06-11 10:53:02 +0900
committertmk <nobody@nowhere>2012-06-11 10:53:02 +0900
commit62d1ebb91c7b381ce3d88aad9ee0b03bea9fce26 (patch)
tree6b10864a310f611187e1b61102da7da1db1d2e29 /protocol/ps2.c
parent225de7a847a511d004bf909b1334e19497cf2f9d (diff)
parent81706d1130fdc3c0d6d110f4d8665c47ffd7fb59 (diff)
Merge branch 'newdir'
Diffstat (limited to 'protocol/ps2.c')
-rw-r--r--protocol/ps2.c434
1 files changed, 434 insertions, 0 deletions
diff --git a/protocol/ps2.c b/protocol/ps2.c
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+++ b/protocol/ps2.c
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+/*
+Copyright 2010,2011 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.
+*/
+
+#include <stdbool.h>
+#include <avr/io.h>
+#include <avr/interrupt.h>
+#include <util/delay.h>
+#include "ps2.h"
+#include "debug.h"
+
+
+static uint8_t recv_data(void);
+static inline void clock_lo(void);
+static inline void clock_hi(void);
+static inline bool clock_in(void);
+static inline void data_lo(void);
+static inline void data_hi(void);
+static inline bool data_in(void);
+static inline uint16_t wait_clock_lo(uint16_t us);
+static inline uint16_t wait_clock_hi(uint16_t us);
+static inline uint16_t wait_data_lo(uint16_t us);
+static inline uint16_t wait_data_hi(uint16_t us);
+static inline void idle(void);
+static inline void inhibit(void);
+
+
+/*
+Primitive PS/2 Library for AVR
+==============================
+Host side is only supported now.
+
+
+I/O control
+-----------
+High state is asserted by input with pull up.
+
+
+PS/2 References
+---------------
+http://www.computer-engineering.org/ps2protocol/
+http://www.mcamafia.de/pdf/ibm_hitrc07.pdf
+*/
+
+
+#define WAIT(stat, us, err) do { \
+ if (!wait_##stat(us)) { \
+ ps2_error = err; \
+ goto ERROR; \
+ } \
+} while (0)
+
+
+uint8_t ps2_error = PS2_ERR_NONE;
+
+
+void ps2_host_init(void)
+{
+#ifdef PS2_INT_ENABLE
+ PS2_INT_ENABLE();
+ idle();
+#else
+ inhibit();
+#endif
+}
+
+// TODO: send using interrupt if available
+uint8_t ps2_host_send(uint8_t data)
+{
+ uint8_t res = 0;
+ bool parity = true;
+ ps2_error = PS2_ERR_NONE;
+#ifdef PS2_INT_DISABLE
+ PS2_INT_DISABLE();
+#endif
+ /* terminate a transmission if we have */
+ inhibit();
+ _delay_us(100);
+
+ /* start bit [1] */
+ data_lo();
+ clock_hi();
+ WAIT(clock_lo, 15000, 1);
+ /* data [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 [10] */
+ _delay_us(15);
+ if (parity) { data_hi(); } else { data_lo(); }
+ WAIT(clock_hi, 50, 4);
+ WAIT(clock_lo, 50, 5);
+ /* stop bit [11] */
+ _delay_us(15);
+ data_hi();
+ /* ack [12] */
+ WAIT(data_lo, 50, 6);
+ WAIT(clock_lo, 50, 7);
+
+ /* wait for idle state */
+ WAIT(clock_hi, 50, 8);
+ WAIT(data_hi, 50, 9);
+
+ res = ps2_host_recv_response();
+ERROR:
+#ifdef PS2_INT_ENABLE
+ PS2_INT_ENABLE();
+ idle();
+#else
+ inhibit();
+#endif
+ return res;
+}
+
+/* receive data when host want else inhibit communication */
+uint8_t ps2_host_recv_response(void)
+{
+ uint8_t data = 0;
+
+ /* terminate a transmission if we have */
+ inhibit();
+ _delay_us(100);
+
+ /* release lines(idle state) */
+ idle();
+
+ /* wait start bit */
+ wait_clock_lo(2000);
+ data = recv_data();
+
+ inhibit();
+ return data;
+}
+
+#ifndef PS2_INT_VECT
+uint8_t ps2_host_recv(void)
+{
+ return ps2_host_recv_response();
+}
+#else
+/* ring buffer to store ps/2 key data */
+#define PBUF_SIZE 8
+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)
+{
+ if (!data)
+ return;
+
+ 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 {
+ debug("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;
+}
+
+/* get data received by interrupt */
+uint8_t ps2_host_recv(void)
+{
+ if (ps2_error) {
+ print("x");
+ phex(ps2_error);
+ ps2_host_send(0xFE); // request to resend
+ ps2_error = PS2_ERR_NONE;
+ }
+ idle();
+ return pbuf_dequeue();
+}
+
+#if 0
+#define DEBUGP_INIT() do { DDRC = 0xFF; } while (0)
+#define DEBUGP(x) do { PORTC = x; } while (0)
+#else
+#define DEBUGP_INIT()
+#define DEBUGP(x)
+#endif
+ISR(PS2_INT_VECT)
+{
+ static enum {
+ INIT,
+ START,
+ BIT0, BIT1, BIT2, BIT3, BIT4, BIT5, BIT6, BIT7,
+ PARITY,
+ STOP,
+ } state = INIT;
+ static uint8_t data = 0;
+ static uint8_t parity = 1;
+
+ // TODO: abort if elapse 100us from previous interrupt
+
+ // return unless falling edge
+ if (clock_in()) {
+ goto RETURN;
+ }
+
+ state++;
+ DEBUGP(state);
+ switch (state) {
+ case START:
+ if (data_in())
+ goto ERROR;
+ break;
+ case BIT0:
+ case BIT1:
+ case BIT2:
+ case BIT3:
+ case BIT4:
+ case BIT5:
+ case BIT6:
+ case BIT7:
+ data >>= 1;
+ if (data_in()) {
+ data |= 0x80;
+ parity++;
+ }
+ 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;
+ pbuf_enqueue(data);
+ goto DONE;
+ break;
+ default:
+ goto ERROR;
+ }
+ goto RETURN;
+ERROR:
+ DEBUGP(0x0F);
+ inhibit();
+ ps2_error = state;
+DONE:
+ state = INIT;
+ data = 0;
+ parity = 1;
+RETURN:
+ return;
+}
+#endif
+
+
+static void ps2_reset(void)
+{
+ ps2_host_send(0xFF);
+}
+
+/* send LED state to keyboard */
+void ps2_host_set_led(uint8_t led)
+{
+ ps2_host_send(0xED);
+ ps2_host_send(led);
+}
+
+
+/* called after start bit comes */
+static uint8_t recv_data(void)
+{
+ uint8_t data = 0;
+ bool parity = true;
+ ps2_error = PS2_ERR_NONE;
+
+ /* start bit [1] */
+ WAIT(clock_lo, 1, 1);
+ WAIT(data_lo, 1, 2);
+ WAIT(clock_hi, 50, 3);
+
+ /* data [2-9] */
+ for (uint8_t i = 0; i < 8; i++) {
+ WAIT(clock_lo, 50, 4);
+ if (data_in()) {
+ parity = !parity;
+ data |= (1<<i);
+ }
+ WAIT(clock_hi, 50, 5);
+ }
+
+ /* parity [10] */
+ WAIT(clock_lo, 50, 6);
+ if (data_in() != parity) {
+ ps2_error = PS2_ERR_PARITY;
+ goto ERROR;
+ }
+ WAIT(clock_hi, 50, 7);
+
+ /* stop bit [11] */
+ WAIT(clock_lo, 50, 8);
+ WAIT(data_hi, 1, 9);
+ WAIT(clock_hi, 50, 10);
+
+ return data;
+ERROR:
+ return 0;
+}
+
+static inline void clock_lo()
+{
+ PS2_CLOCK_PORT &= ~(1<<PS2_CLOCK_BIT);
+ PS2_CLOCK_DDR |= (1<<PS2_CLOCK_BIT);
+}
+static inline void clock_hi()
+{
+ /* input with pull up */
+ PS2_CLOCK_DDR &= ~(1<<PS2_CLOCK_BIT);
+ PS2_CLOCK_PORT |= (1<<PS2_CLOCK_BIT);
+}
+static inline bool clock_in()
+{
+ PS2_CLOCK_DDR &= ~(1<<PS2_CLOCK_BIT);
+ PS2_CLOCK_PORT |= (1<<PS2_CLOCK_BIT);
+ _delay_us(1);
+ return PS2_CLOCK_PIN&(1<<PS2_CLOCK_BIT);
+}
+static inline void data_lo()
+{
+ PS2_DATA_PORT &= ~(1<<PS2_DATA_BIT);
+ PS2_DATA_DDR |= (1<<PS2_DATA_BIT);
+}
+static inline void data_hi()
+{
+ /* input with pull up */
+ PS2_DATA_DDR &= ~(1<<PS2_DATA_BIT);
+ PS2_DATA_PORT |= (1<<PS2_DATA_BIT);
+}
+static inline bool data_in()
+{
+ PS2_DATA_DDR &= ~(1<<PS2_DATA_BIT);
+ PS2_DATA_PORT |= (1<<PS2_DATA_BIT);
+ _delay_us(1);
+ return PS2_DATA_PIN&(1<<PS2_DATA_BIT);
+}
+
+static inline uint16_t wait_clock_lo(uint16_t us)
+{
+ while (clock_in() && us) { asm(""); _delay_us(1); us--; }
+ return us;
+}
+static inline uint16_t wait_clock_hi(uint16_t us)
+{
+ while (!clock_in() && us) { asm(""); _delay_us(1); us--; }
+ return us;
+}
+static inline uint16_t wait_data_lo(uint16_t us)
+{
+ while (data_in() && us) { asm(""); _delay_us(1); us--; }
+ return us;
+}
+static inline uint16_t wait_data_hi(uint16_t us)
+{
+ while (!data_in() && us) { asm(""); _delay_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();
+}