diff options
Diffstat (limited to 'drivers/ps2/ps2_busywait.c')
| -rw-r--r-- | drivers/ps2/ps2_busywait.c | 187 | 
1 files changed, 187 insertions, 0 deletions
| diff --git a/drivers/ps2/ps2_busywait.c b/drivers/ps2/ps2_busywait.c new file mode 100644 index 0000000000..983194eea8 --- /dev/null +++ b/drivers/ps2/ps2_busywait.c @@ -0,0 +1,187 @@ +/* +Copyright 2010,2011,2012,2013 Jun WAKO <[email protected]> + +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 busywait version + */ + +#include <stdbool.h> +#include "wait.h" +#include "ps2.h" +#include "ps2_io.h" +#include "debug.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; + +void ps2_host_init(void) { +    clock_init(); +    data_init(); + +    // POR(150-2000ms) plus BAT(300-500ms) may take 2.5sec([3]p.20) +    wait_ms(2500); + +    inhibit(); +} + +uint8_t ps2_host_send(uint8_t data) { +    bool parity = true; +    ps2_error   = PS2_ERR_NONE; + +    /* 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, 10);  // 10ms [5]p.50 + +    /* Data bit */ +    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); + +    inhibit(); +    return ps2_host_recv_response(); +ERROR: +    inhibit(); +    return 0; +} + +/* receive data when host want else inhibit communication */ +uint8_t ps2_host_recv_response(void) { +    // Command may take 25ms/20ms at most([5]p.46, [3]p.21) +    // 250 * 100us(wait for start bit in ps2_host_recv) +    uint8_t data = 0; +    uint8_t try +        = 250; +    do { +        data = ps2_host_recv(); +    } while (try --&&ps2_error); +    return data; +} + +/* called after start bit comes */ +uint8_t ps2_host_recv(void) { +    uint8_t data   = 0; +    bool    parity = true; +    ps2_error      = PS2_ERR_NONE; + +    /* release lines(idle state) */ +    idle(); + +    /* start bit [1] */ +    WAIT(clock_lo, 100, 1);  // TODO: this is enough? +    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); + +    inhibit(); +    return data; +ERROR: +    if (ps2_error > PS2_ERR_STARTBIT3) { +        xprintf("x%02X\n", ps2_error); +    } +    inhibit(); +    return 0; +} + +/* send LED state to keyboard */ +void ps2_host_set_led(uint8_t led) { +    ps2_host_send(0xED); +    ps2_host_send(led); +} | 
