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Diffstat (limited to 'hid/pico/src/ph_spi.c')
| -rw-r--r-- | hid/pico/src/ph_spi.c | 120 |
1 files changed, 120 insertions, 0 deletions
diff --git a/hid/pico/src/ph_spi.c b/hid/pico/src/ph_spi.c new file mode 100644 index 00000000..ef74bd7e --- /dev/null +++ b/hid/pico/src/ph_spi.c @@ -0,0 +1,120 @@ +/***************************************************************************** +# # +# KVMD - The main PiKVM daemon. # +# # +# Copyright (C) 2018-2023 Maxim Devaev <[email protected]> # +# # +# This program is free software: you can redistribute it and/or modify # +# it under the terms of the GNU General Public License as published by # +# the Free Software Foundation, either version 3 of the License, or # +# (at your option) any later version. # +# # +# This program is distributed in the hope that it will be useful, # +# but WITHOUT ANY WARRANTY; without even the implied warranty of # +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # +# GNU General Public License for more details. # +# # +# You should have received a copy of the GNU General Public License # +# along with this program. If not, see <https://www.gnu.org/licenses/>. # +# # +*****************************************************************************/ + + +#include "ph_spi.h" + +#include "hardware/gpio.h" +#include "hardware/irq.h" +#include "hardware/spi.h" +#include "hardware/regs/spi.h" + +#include "ph_types.h" + + +#define _BUS spi0 +#define _IRQ SPI0_IRQ +#define _FREQ (2 * 1000 * 1000) +#define _CS_PIN 21 +#define _RX_PIN 20 +#define _TX_PIN 19 +#define _CLK_PIN 18 + + +static volatile u8 _in_buf[8] = {0}; +static volatile u8 _in_index = 0; + +static volatile u8 _out_buf[8] = {0}; +static volatile u8 _out_index = 0; + +static void (*_data_cb)(const u8 *) = NULL; + + +static void _xfer_isr(void); + + +void ph_spi_init(void (*data_cb)(const u8 *)) { + _data_cb = data_cb; + + spi_init(_BUS, _FREQ); + spi_set_slave(_BUS, true); + spi_set_format(_BUS, 8, SPI_CPOL_0, SPI_CPHA_0, SPI_MSB_FIRST); + + gpio_set_function(_CS_PIN, GPIO_FUNC_SPI); + gpio_set_function(_RX_PIN, GPIO_FUNC_SPI); + gpio_set_function(_TX_PIN, GPIO_FUNC_SPI); + gpio_set_function(_CLK_PIN, GPIO_FUNC_SPI); + + // https://github.com/raspberrypi/pico-sdk/blob/master/src/rp2040/hardware_regs/include/hardware/regs/spi.h + irq_set_exclusive_handler(_IRQ, _xfer_isr); + spi_get_hw(_BUS)->imsc = SPI_SSPIMSC_RXIM_BITS | SPI_SSPIMSC_TXIM_BITS; + irq_set_enabled(_IRQ, true); +} + +void ph_spi_task(void) { + if (!_out_buf[0] && _in_index == 8) { + _data_cb((const u8 *)_in_buf); + } +} + +void ph_spi_write(const u8 *data) { + // Меджик в нулевом байте разрешает начать ответ + for (s8 i = 7; i >= 0; --i) { + _out_buf[i] = data[i]; + } +} + +void __isr __not_in_flash_func(_xfer_isr)(void) { +# define SR (spi_get_hw(_BUS)->sr) +# define DR (spi_get_hw(_BUS)->dr) + + while (SR & SPI_SSPSR_TNF_BITS) { + if (_out_buf[0] && _out_index < 8) { + DR = (u32)_out_buf[_out_index]; + ++_out_index; + if (_out_index == 8) { + _out_index = 0; + _in_index = 0; + _out_buf[0] = 0; + } + } else { + DR = (u32)0; + } + } + + while (SR & SPI_SSPSR_RNE_BITS) { + static bool receiving = false; + const u8 in = DR; + if (!receiving && in != 0) { + receiving = true; + } + if (receiving && _in_index < 8) { + _in_buf[_in_index] = in; + ++_in_index; + } + if (_in_index == 8) { + receiving = false; + } + } + +# undef DR +# undef SR +} |