/*

* The MIT License (MIT)

*

* Copyright (c) 2021 Raspberry Pi (Trading) Ltd.

*

* Permission is hereby granted, free of charge, to any person obtaining a copy

* of this software and associated documentation files (the "Software"), to deal

* in the Software without restriction, including without limitation the rights

* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

* copies of the Software, and to permit persons to whom the Software is

* furnished to do so, subject to the following conditions:

*

* The above copyright notice and this permission notice shall be included in

* all copies or substantial portions of the Software.

*

* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

* THE SOFTWARE.

*

*/

#include <pico/stdlib.h>

#include <stdio.h>

#include <string.h>

#include <hardware/clocks.h>

#include <hardware/gpio.h>

#include "probe_config.h"

#include "probe.h"

#include "tusb.h"

#define DIV_ROUND_UP(m, n) (((m) + (n) - 1) / (n))

// Only want to set / clear one gpio per event so go up in powers of 2

enum _dbg_pins {

DBG_PIN_WRITE = 1,

DBG_PIN_WRITE_WAIT = 2,

DBG_PIN_READ = 4,

DBG_PIN_PKT = 8,

};

CU_REGISTER_DEBUG_PINS(probe_timing)

// Uncomment to enable debug

//CU_SELECT_DEBUG_PINS(probe_timing)

#define PROBE_BUF_SIZE 8192

struct _probe {

// PIO offset

uint offset;

uint initted;

};

static struct _probe probe;

void probe_set_swclk_freq(uint freq_khz) {

uint clk_sys_freq_khz = clock_get_hz(clk_sys) / 1000;

probe_info("Set swclk freq %dKHz sysclk %dkHz\n", freq_khz, clk_sys_freq_khz);

// Round up (otherwise fast swclks get faster)

uint32_t divider = (((clk_sys_freq_khz + freq_khz - 1)/ freq_khz) + 3) / 4;

if (divider == 0)

divider = 1;

if (divider > 65535)

divider = 65535;

pio_sm_set_clkdiv_int_frac(pio0, PROBE_SM, divider, 0);

}

void probe_assert_reset(bool state)

{

#if defined(PROBE_PIN_RESET)

/* Change the direction to out to drive pin to 0 or to in to emulate open drain */

gpio_set_dir(PROBE_PIN_RESET, state == 0 ? GPIO_OUT : GPIO_IN);

#endif

}

int probe_reset_level(void)

{

#if defined(PROBE_PIN_RESET)

return gpio_get(PROBE_PIN_RESET);

#else

return 0;

#endif

}

typedef enum probe_pio_command {

CMD_WRITE = 0,

CMD_SKIP,

CMD_TURNAROUND,

CMD_READ

} probe_pio_command_t;

static inline uint32_t fmt_probe_command(uint bit_count, bool out_en, probe_pio_command_t cmd) {

uint cmd_addr =

cmd == CMD_WRITE ? probe.offset + probe_offset_write_cmd :

cmd == CMD_SKIP ? probe.offset + probe_offset_get_next_cmd :

cmd == CMD_TURNAROUND ? probe.offset + probe_offset_turnaround_cmd :

probe.offset + probe_offset_read_cmd;

return ((bit_count - 1) & 0xff) | ((uint)out_en << 8) | (cmd_addr << 9);

}

void probe_write_bits(uint bit_count, uint32_t data_byte) {

DEBUG_PINS_SET(probe_timing, DBG_PIN_WRITE);

pio_sm_put_blocking(pio0, PROBE_SM, fmt_probe_command(bit_count, true, CMD_WRITE));

pio_sm_put_blocking(pio0, PROBE_SM, data_byte);

probe_dump("Write %d bits 0x%x\n", bit_count, data_byte);

// Return immediately so we can cue up the next command whilst this one runs

DEBUG_PINS_CLR(probe_timing, DBG_PIN_WRITE);

}

void probe_hiz_clocks(uint bit_count) {

pio_sm_put_blocking(pio0, PROBE_SM, fmt_probe_command(bit_count, false, CMD_TURNAROUND));

pio_sm_put_blocking(pio0, PROBE_SM, 0);

}

uint32_t probe_read_bits(uint bit_count) {

DEBUG_PINS_SET(probe_timing, DBG_PIN_READ);

pio_sm_put_blocking(pio0, PROBE_SM, fmt_probe_command(bit_count, false, CMD_READ));

uint32_t data = pio_sm_get_blocking(pio0, PROBE_SM);

uint32_t data_shifted = data;

if (bit_count < 32) {

data_shifted = data >> (32 - bit_count);

}

probe_dump("Read %d bits 0x%x (shifted 0x%x)\n", bit_count, data, data_shifted);

DEBUG_PINS_CLR(probe_timing, DBG_PIN_READ);

return data_shifted;

}

static void probe_wait_idle() {

pio0->fdebug = 1u << (PIO_FDEBUG_TXSTALL_LSB + PROBE_SM);

while (!(pio0->fdebug & (1u << (PIO_FDEBUG_TXSTALL_LSB + PROBE_SM))))

;

}

void probe_read_mode(void) {

pio_sm_put_blocking(pio0, PROBE_SM, fmt_probe_command(0, false, CMD_SKIP));

probe_wait_idle();

}

void probe_write_mode(void) {

pio_sm_put_blocking(pio0, PROBE_SM, fmt_probe_command(0, true, CMD_SKIP));

probe_wait_idle();

}

void probe_init() {

if (!probe.initted) {

probe_gpio_init();

uint offset = pio_add_program(pio0, &probe_program);

probe.offset = offset;

pio_sm_config sm_config = probe_program_get_default_config(offset);

probe_sm_init(&sm_config);

pio_sm_init(pio0, PROBE_SM, offset, &sm_config);

// Set up divisor

probe_set_swclk_freq(1000);

// Jump SM to command dispatch routine, and enable it

pio_sm_exec(pio0, PROBE_SM, offset + probe_offset_get_next_cmd);

pio_sm_set_enabled(pio0, PROBE_SM, 1);

probe.initted = 1;

}

}

void probe_deinit(void)

{

if (probe.initted) {

probe_read_mode();

pio_sm_set_enabled(pio0, PROBE_SM, 0);

pio_remove_program(pio0, &probe_program, probe.offset);

probe_assert_reset(1); // de-assert nRESET

probe_gpio_deinit();

probe.initted = 0;

}

}