079cc940a6
Runs in microwatt (GHDL and FPGA) and qemu. Port done initially by Michael Neuling, with help from Anton Blanchard and Jordan Niethe.
122 lines
3.4 KiB
C
122 lines
3.4 KiB
C
/*
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* This file is part of the MicroPython project, http://micropython.org/
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*
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* The MIT License (MIT)
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*
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* Copyright (c) 2019, Michael Neuling, IBM Corporation.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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/*
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* This is a driver for the potato UART used by the microwatt core.
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* The original potato UART came from here
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* https://github.com/skordal/potato
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*/
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#include <unistd.h>
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#include <stdbool.h>
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#include "py/mpconfig.h"
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#define PROC_FREQ 50000000
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#define UART_FREQ 115200
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#define POTATO_UART_BASE 0xc0002000
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uint64_t potato_uart_base;
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#define POTATO_CONSOLE_TX 0x00
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#define POTATO_CONSOLE_RX 0x08
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#define POTATO_CONSOLE_STATUS 0x10
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#define POTATO_CONSOLE_STATUS_RX_EMPTY 0x01
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#define POTATO_CONSOLE_STATUS_TX_EMPTY 0x02
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#define POTATO_CONSOLE_STATUS_RX_FULL 0x04
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#define POTATO_CONSOLE_STATUS_TX_FULL 0x08
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#define POTATO_CONSOLE_CLOCK_DIV 0x18
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#define POTATO_CONSOLE_IRQ_EN 0x20
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static uint64_t potato_uart_reg_read(int offset) {
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uint64_t addr;
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uint64_t val;
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addr = potato_uart_base + offset;
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val = *(volatile uint64_t *)addr;
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return val;
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}
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void potato_uart_reg_write(int offset, uint64_t val) {
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uint64_t addr;
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addr = potato_uart_base + offset;
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*(volatile uint64_t *)addr = val;
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}
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static int potato_uart_rx_empty(void) {
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uint64_t val;
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val = potato_uart_reg_read(POTATO_CONSOLE_STATUS);
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if (val & POTATO_CONSOLE_STATUS_RX_EMPTY) {
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return 1;
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}
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return 0;
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}
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static int potato_uart_tx_full(void) {
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uint64_t val;
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val = potato_uart_reg_read(POTATO_CONSOLE_STATUS);
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if (val & POTATO_CONSOLE_STATUS_TX_FULL) {
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return 1;
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}
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return 0;
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}
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static unsigned long potato_uart_divisor(unsigned long proc_freq, unsigned long uart_freq) {
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return proc_freq / (uart_freq * 16) - 1;
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}
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void potato_uart_init(void) {
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potato_uart_base = POTATO_UART_BASE;
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potato_uart_reg_write(POTATO_CONSOLE_CLOCK_DIV, potato_uart_divisor(PROC_FREQ, UART_FREQ));
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}
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char potato_uart_read(void) {
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uint64_t val;
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while (potato_uart_rx_empty());
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val = potato_uart_reg_read(POTATO_CONSOLE_RX);
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return (char)(val & 0x000000ff);
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}
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void potato_uart_write(char c) {
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uint64_t val;
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val = c;
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while (potato_uart_tx_full());
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potato_uart_reg_write(POTATO_CONSOLE_TX, val);
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}
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