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micropython/ports/rp2/machine_spi.c

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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2020-2021 Damien P. George
*
* 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 "py/runtime.h"
#include "py/mphal.h"
#include "py/mperrno.h"
#include "extmod/machine_spi.h"
#include "modmachine.h"
#include "hardware/spi.h"
#include "hardware/dma.h"
#define DEFAULT_SPI_BAUDRATE (1000000)
#define DEFAULT_SPI_POLARITY (0)
#define DEFAULT_SPI_PHASE (0)
#define DEFAULT_SPI_BITS (8)
#define DEFAULT_SPI_FIRSTBIT (SPI_MSB_FIRST)
#ifndef MICROPY_HW_SPI0_SCK
#if PICO_DEFAULT_SPI == 0
#define MICROPY_HW_SPI0_SCK (PICO_DEFAULT_SPI_SCK_PIN)
#define MICROPY_HW_SPI0_MOSI (PICO_DEFAULT_SPI_TX_PIN)
#define MICROPY_HW_SPI0_MISO (PICO_DEFAULT_SPI_RX_PIN)
#else
#define MICROPY_HW_SPI0_SCK (6)
#define MICROPY_HW_SPI0_MOSI (7)
#define MICROPY_HW_SPI0_MISO (4)
#endif
#endif
#ifndef MICROPY_HW_SPI1_SCK
#if PICO_DEFAULT_SPI == 1
#define MICROPY_HW_SPI1_SCK (PICO_DEFAULT_SPI_SCK_PIN)
#define MICROPY_HW_SPI1_MOSI (PICO_DEFAULT_SPI_TX_PIN)
#define MICROPY_HW_SPI1_MISO (PICO_DEFAULT_SPI_RX_PIN)
#else
#define MICROPY_HW_SPI1_SCK (10)
#define MICROPY_HW_SPI1_MOSI (11)
#define MICROPY_HW_SPI1_MISO (8)
#endif
#endif
// SPI0 can be GP{0..7,16..23}, SPI1 can be GP{8..15,24..29}.
#define IS_VALID_PERIPH(spi, pin) ((((pin) & 8) >> 3) == (spi))
// GP{2,6,10,14,...}
#define IS_VALID_SCK(spi, pin) (((pin) & 3) == 2 && IS_VALID_PERIPH(spi, pin))
// GP{3,7,11,15,...}
#define IS_VALID_MOSI(spi, pin) (((pin) & 3) == 3 && IS_VALID_PERIPH(spi, pin))
// GP{0,4,8,10,...}
#define IS_VALID_MISO(spi, pin) (((pin) & 3) == 0 && IS_VALID_PERIPH(spi, pin))
typedef struct _machine_spi_obj_t {
mp_obj_base_t base;
spi_inst_t *const spi_inst;
uint8_t spi_id;
uint8_t polarity;
uint8_t phase;
uint8_t bits;
uint8_t firstbit;
uint8_t sck;
uint8_t mosi;
uint8_t miso;
uint32_t baudrate;
} machine_spi_obj_t;
STATIC machine_spi_obj_t machine_spi_obj[] = {
{
{&machine_spi_type}, spi0, 0,
DEFAULT_SPI_POLARITY, DEFAULT_SPI_PHASE, DEFAULT_SPI_BITS, DEFAULT_SPI_FIRSTBIT,
MICROPY_HW_SPI0_SCK, MICROPY_HW_SPI0_MOSI, MICROPY_HW_SPI0_MISO,
0,
},
{
{&machine_spi_type}, spi1, 1,
DEFAULT_SPI_POLARITY, DEFAULT_SPI_PHASE, DEFAULT_SPI_BITS, DEFAULT_SPI_FIRSTBIT,
MICROPY_HW_SPI1_SCK, MICROPY_HW_SPI1_MOSI, MICROPY_HW_SPI1_MISO,
0,
},
};
STATIC void machine_spi_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
machine_spi_obj_t *self = MP_OBJ_TO_PTR(self_in);
mp_printf(print, "SPI(%u, baudrate=%u, polarity=%u, phase=%u, bits=%u, sck=%u, mosi=%u, miso=%u)",
self->spi_id, self->baudrate, self->polarity, self->phase, self->bits,
self->sck, self->mosi, self->miso);
}
mp_obj_t machine_spi_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args) {
enum { ARG_id, ARG_baudrate, ARG_polarity, ARG_phase, ARG_bits, ARG_firstbit, ARG_sck, ARG_mosi, ARG_miso };
static const mp_arg_t allowed_args[] = {
{ MP_QSTR_id, MP_ARG_REQUIRED | MP_ARG_OBJ },
{ MP_QSTR_baudrate, MP_ARG_INT, {.u_int = DEFAULT_SPI_BAUDRATE} },
{ MP_QSTR_polarity, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = DEFAULT_SPI_POLARITY} },
{ MP_QSTR_phase, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = DEFAULT_SPI_PHASE} },
{ MP_QSTR_bits, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = DEFAULT_SPI_BITS} },
{ MP_QSTR_firstbit, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = DEFAULT_SPI_FIRSTBIT} },
{ MP_QSTR_sck, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
{ MP_QSTR_mosi, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
{ MP_QSTR_miso, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
};
// Parse the arguments.
mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
mp_arg_parse_all_kw_array(n_args, n_kw, all_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
// Get the SPI bus id.
int spi_id = mp_obj_get_int(args[ARG_id].u_obj);
if (spi_id < 0 || spi_id >= MP_ARRAY_SIZE(machine_spi_obj)) {
mp_raise_msg_varg(&mp_type_ValueError, MP_ERROR_TEXT("SPI(%d) doesn't exist"), spi_id);
}
// Get static peripheral object.
machine_spi_obj_t *self = (machine_spi_obj_t *)&machine_spi_obj[spi_id];
// Set SCK/MOSI/MISO pins if configured.
if (args[ARG_sck].u_obj != mp_const_none) {
int sck = mp_hal_get_pin_obj(args[ARG_sck].u_obj);
if (!IS_VALID_SCK(self->spi_id, sck)) {
mp_raise_ValueError(MP_ERROR_TEXT("bad SCK pin"));
}
self->sck = sck;
}
if (args[ARG_mosi].u_obj != mp_const_none) {
int mosi = mp_hal_get_pin_obj(args[ARG_mosi].u_obj);
if (!IS_VALID_MOSI(self->spi_id, mosi)) {
mp_raise_ValueError(MP_ERROR_TEXT("bad MOSI pin"));
}
self->mosi = mosi;
}
if (args[ARG_miso].u_obj != mp_const_none) {
int miso = mp_hal_get_pin_obj(args[ARG_miso].u_obj);
if (!IS_VALID_MISO(self->spi_id, miso)) {
mp_raise_ValueError(MP_ERROR_TEXT("bad MISO pin"));
}
self->miso = miso;
}
// Initialise the SPI peripheral if any arguments given, or it was not initialised previously.
if (n_args > 1 || n_kw > 0 || self->baudrate == 0) {
self->baudrate = args[ARG_baudrate].u_int;
self->polarity = args[ARG_polarity].u_int;
self->phase = args[ARG_phase].u_int;
self->bits = args[ARG_bits].u_int;
self->firstbit = args[ARG_firstbit].u_int;
if (self->firstbit == SPI_LSB_FIRST) {
mp_raise_NotImplementedError(MP_ERROR_TEXT("LSB"));
}
spi_init(self->spi_inst, self->baudrate);
self->baudrate = spi_set_baudrate(self->spi_inst, self->baudrate);
spi_set_format(self->spi_inst, self->bits, self->polarity, self->phase, self->firstbit);
gpio_set_function(self->sck, GPIO_FUNC_SPI);
gpio_set_function(self->miso, GPIO_FUNC_SPI);
gpio_set_function(self->mosi, GPIO_FUNC_SPI);
}
return MP_OBJ_FROM_PTR(self);
}
STATIC void machine_spi_init(mp_obj_base_t *self_in, size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
enum { ARG_baudrate, ARG_polarity, ARG_phase, ARG_bits, ARG_firstbit };
static const mp_arg_t allowed_args[] = {
{ MP_QSTR_baudrate, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
{ MP_QSTR_polarity, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
{ MP_QSTR_phase, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
{ MP_QSTR_bits, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
{ MP_QSTR_firstbit, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
};
// Parse the arguments.
machine_spi_obj_t *self = (machine_spi_obj_t *)self_in;
mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
mp_arg_parse_all(n_args, pos_args, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
// Reconfigure the baudrate if requested.
if (args[ARG_baudrate].u_int != -1) {
self->baudrate = spi_set_baudrate(self->spi_inst, args[ARG_baudrate].u_int);
}
// Reconfigure the format if requested.
bool set_format = false;
if (args[ARG_polarity].u_int != -1) {
self->polarity = args[ARG_polarity].u_int;
set_format = true;
}
if (args[ARG_phase].u_int != -1) {
self->phase = args[ARG_phase].u_int;
set_format = true;
}
if (args[ARG_bits].u_int != -1) {
self->bits = args[ARG_bits].u_int;
set_format = true;
}
if (args[ARG_firstbit].u_int != -1) {
self->firstbit = args[ARG_firstbit].u_int;
if (self->firstbit == SPI_LSB_FIRST) {
mp_raise_NotImplementedError(MP_ERROR_TEXT("LSB"));
}
}
if (set_format) {
spi_set_format(self->spi_inst, self->bits, self->polarity, self->phase, self->firstbit);
}
}
STATIC void machine_spi_transfer(mp_obj_base_t *self_in, size_t len, const uint8_t *src, uint8_t *dest) {
machine_spi_obj_t *self = (machine_spi_obj_t *)self_in;
// Use DMA for large transfers if channels are available
const size_t dma_min_size_threshold = 32;
int chan_tx = -1;
int chan_rx = -1;
if (len >= dma_min_size_threshold) {
// Use two DMA channels to service the two FIFOs
chan_tx = dma_claim_unused_channel(false);
chan_rx = dma_claim_unused_channel(false);
}
bool use_dma = chan_rx >= 0 && chan_tx >= 0;
// note src is guaranteed to be non-NULL
bool write_only = dest == NULL;
if (use_dma) {
uint8_t dev_null;
dma_channel_config c = dma_channel_get_default_config(chan_tx);
channel_config_set_transfer_data_size(&c, DMA_SIZE_8);
channel_config_set_dreq(&c, spi_get_index(self->spi_inst) ? DREQ_SPI1_TX : DREQ_SPI0_TX);
dma_channel_configure(chan_tx, &c,
&spi_get_hw(self->spi_inst)->dr,
src,
len,
false);
c = dma_channel_get_default_config(chan_rx);
channel_config_set_transfer_data_size(&c, DMA_SIZE_8);
channel_config_set_dreq(&c, spi_get_index(self->spi_inst) ? DREQ_SPI1_RX : DREQ_SPI0_RX);
channel_config_set_read_increment(&c, false);
channel_config_set_write_increment(&c, !write_only);
dma_channel_configure(chan_rx, &c,
write_only ? &dev_null : dest,
&spi_get_hw(self->spi_inst)->dr,
len,
false);
dma_start_channel_mask((1u << chan_rx) | (1u << chan_tx));
dma_channel_wait_for_finish_blocking(chan_rx);
dma_channel_wait_for_finish_blocking(chan_tx);
}
// If we have claimed only one channel successfully, we should release immediately
if (chan_rx >= 0) {
dma_channel_unclaim(chan_rx);
}
if (chan_tx >= 0) {
dma_channel_unclaim(chan_tx);
}
if (!use_dma) {
// Use software for small transfers, or if couldn't claim two DMA channels
if (write_only) {
spi_write_blocking(self->spi_inst, src, len);
} else {
spi_write_read_blocking(self->spi_inst, src, dest, len);
}
}
}
STATIC const mp_machine_spi_p_t machine_spi_p = {
.init = machine_spi_init,
.transfer = machine_spi_transfer,
};
const mp_obj_type_t machine_spi_type = {
{ &mp_type_type },
.name = MP_QSTR_SPI,
.print = machine_spi_print,
.make_new = machine_spi_make_new,
.protocol = &machine_spi_p,
.locals_dict = (mp_obj_dict_t *)&mp_machine_spi_locals_dict,
};
mp_obj_base_t *mp_hal_get_spi_obj(mp_obj_t o) {
if (mp_obj_is_type(o, &machine_spi_type)) {
return MP_OBJ_TO_PTR(o);
}
#if MICROPY_PY_MACHINE_SOFTSPI
else if (mp_obj_is_type(o, &mp_machine_soft_spi_type)) {
return MP_OBJ_TO_PTR(o);
}
#endif
else {
mp_raise_TypeError(MP_ERROR_TEXT("expecting an SPI object"));
}
}
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