circuitpython/ports/powerpc/uart_lpc_serial.c

112 lines
3.2 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 the LPC serial UART used by POWER9 boxes. This is modelled
* in the qemu POWER9 machine.
*/
#include <unistd.h>
#include <stdbool.h>
#include "py/mpconfig.h"
#define PROC_FREQ 50000000
#define UART_FREQ 115200
#define UART_BASE 0xc0002000
#define LPC_UART_BASE 0x60300d00103f8
/* Taken from skiboot */
#define REG_RBR 0
#define REG_THR 0
#define REG_DLL 0
#define REG_IER 1
#define REG_DLM 1
#define REG_FCR 2
#define REG_IIR 2
#define REG_LCR 3
#define REG_MCR 4
#define REG_LSR 5
#define REG_MSR 6
#define REG_SCR 7
#define LSR_DR 0x01 /* Data ready */
#define LSR_OE 0x02 /* Overrun */
#define LSR_PE 0x04 /* Parity error */
#define LSR_FE 0x08 /* Framing error */
#define LSR_BI 0x10 /* Break */
#define LSR_THRE 0x20 /* Xmit holding register empty */
#define LSR_TEMT 0x40 /* Xmitter empty */
#define LSR_ERR 0x80 /* Error */
#define LCR_DLAB 0x80 /* DLL access */
#define IER_RX 0x01
#define IER_THRE 0x02
#define IER_ALL 0x0f
static uint64_t lpc_uart_base;
static void lpc_uart_reg_write(uint64_t offset, uint8_t val) {
uint64_t addr;
addr = lpc_uart_base + offset;
*(volatile uint8_t *)addr = val;
}
static uint8_t lpc_uart_reg_read(uint64_t offset) {
uint64_t addr;
uint8_t val;
addr = lpc_uart_base + offset;
val = *(volatile uint8_t *)addr;
return val;
}
static int lpc_uart_tx_full(void) {
return !(lpc_uart_reg_read(REG_LSR) & LSR_THRE);
}
static int lpc_uart_rx_empty(void) {
return !(lpc_uart_reg_read(REG_LSR) & LSR_DR);
}
void lpc_uart_init(void) {
lpc_uart_base = LPC_UART_BASE;
}
char lpc_uart_read(void) {
while (lpc_uart_rx_empty()) ;
return lpc_uart_reg_read(REG_THR);
}
void lpc_uart_write(char c) {
while (lpc_uart_tx_full());
lpc_uart_reg_write(REG_RBR, c);
}