126 lines
3.4 KiB
C
126 lines
3.4 KiB
C
/*
|
|
* This file is part of the MicroPython project, http://micropython.org/
|
|
*
|
|
* The MIT License (MIT)
|
|
*
|
|
* Copyright (c) 2019, Michael Neuling, IBM Corporation.
|
|
*
|
|
* 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.
|
|
*/
|
|
|
|
/*
|
|
* This is a driver for the potato UART used by the microwatt core.
|
|
* The original potato UART came from here
|
|
* https://github.com/skordal/potato
|
|
*/
|
|
|
|
#include <unistd.h>
|
|
#include <stdbool.h>
|
|
#include "py/mpconfig.h"
|
|
|
|
#define PROC_FREQ 50000000
|
|
#define UART_FREQ 115200
|
|
#define POTATO_UART_BASE 0xc0002000
|
|
uint64_t potato_uart_base;
|
|
|
|
#define POTATO_CONSOLE_TX 0x00
|
|
#define POTATO_CONSOLE_RX 0x08
|
|
#define POTATO_CONSOLE_STATUS 0x10
|
|
#define POTATO_CONSOLE_STATUS_RX_EMPTY 0x01
|
|
#define POTATO_CONSOLE_STATUS_TX_EMPTY 0x02
|
|
#define POTATO_CONSOLE_STATUS_RX_FULL 0x04
|
|
#define POTATO_CONSOLE_STATUS_TX_FULL 0x08
|
|
#define POTATO_CONSOLE_CLOCK_DIV 0x18
|
|
#define POTATO_CONSOLE_IRQ_EN 0x20
|
|
|
|
static uint64_t potato_uart_reg_read(int offset) {
|
|
uint64_t addr;
|
|
uint64_t val;
|
|
|
|
addr = potato_uart_base + offset;
|
|
|
|
val = *(volatile uint64_t *)addr;
|
|
|
|
return val;
|
|
}
|
|
|
|
void potato_uart_reg_write(int offset, uint64_t val) {
|
|
uint64_t addr;
|
|
|
|
addr = potato_uart_base + offset;
|
|
|
|
*(volatile uint64_t *)addr = val;
|
|
}
|
|
|
|
static int potato_uart_rx_empty(void) {
|
|
uint64_t val;
|
|
|
|
val = potato_uart_reg_read(POTATO_CONSOLE_STATUS);
|
|
|
|
if (val & POTATO_CONSOLE_STATUS_RX_EMPTY) {
|
|
return 1;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int potato_uart_tx_full(void) {
|
|
uint64_t val;
|
|
|
|
val = potato_uart_reg_read(POTATO_CONSOLE_STATUS);
|
|
|
|
if (val & POTATO_CONSOLE_STATUS_TX_FULL) {
|
|
return 1;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static unsigned long potato_uart_divisor(unsigned long proc_freq, unsigned long uart_freq) {
|
|
return proc_freq / (uart_freq * 16) - 1;
|
|
}
|
|
|
|
void potato_uart_init(void) {
|
|
potato_uart_base = POTATO_UART_BASE;
|
|
potato_uart_reg_write(POTATO_CONSOLE_CLOCK_DIV, potato_uart_divisor(PROC_FREQ, UART_FREQ));
|
|
|
|
}
|
|
|
|
char potato_uart_read(void) {
|
|
uint64_t val;
|
|
|
|
while (potato_uart_rx_empty()) {
|
|
;
|
|
}
|
|
val = potato_uart_reg_read(POTATO_CONSOLE_RX);
|
|
|
|
return (char)(val & 0x000000ff);
|
|
}
|
|
|
|
void potato_uart_write(char c) {
|
|
uint64_t val;
|
|
|
|
val = c;
|
|
|
|
while (potato_uart_tx_full()) {
|
|
;
|
|
}
|
|
potato_uart_reg_write(POTATO_CONSOLE_TX, val);
|
|
}
|