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/*
* Copyright (c) 2019-2021 Arm Limited. All rights reserved.
*
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the License); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an AS IS BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/* Basic PL011 UART driver */
#include "uart_config.h"
#include "uart_stdout.h"
#include <stdint.h>
#include <stdio.h>
#define CNTLQ 0x11
#define CNTLS 0x13
#define DEL 0x7F
#define BACKSPACE 0x08
#define CR 0x0D
#define LF 0x0A
#define ESC 0x1B
/*****************************************************************************/
/* UART Control Register Locations */
/*****************************************************************************/
#define UART0_DR *((volatile uint32_t *)UART0_BASE)
#define UART0_RSR *((volatile uint32_t *)(UART0_BASE + 0x04))
#define UART0_ECR *((volatile uint32_t *)(UART0_BASE + 0x04))
#define UART0_LCRH *((volatile uint32_t *)(UART0_BASE + 0x2C))
#define UART0_LCRM *((volatile uint32_t *)(UART0_BASE + 0x28))
#define UART0_LCRL *((volatile uint32_t *)(UART0_BASE + 0x24))
#define UART0_CR *((volatile uint32_t *)(UART0_BASE + 0x30))
#define UART0_FR *((volatile uint32_t *)(UART0_BASE + 0x18))
#define UART0_IIR *((volatile uint32_t *)(UART0_BASE + 0x1C))
#define UART0_ICR *((volatile uint32_t *)(UART0_BASE + 0x44))
/*****************************************************************************/
/* Received Status Register - RSR */
/*****************************************************************************/
#define RSR_OVERRUN_ERROR 0x08
#define RSR_BREAK_ERROR 0x04
#define RSR_PARITY_ERROR 0x02
#define RSR_FRAMING_ERROR 0x01
/*****************************************************************************/
/* Line Control High Byte Register - LCRH */
/*****************************************************************************/
#define LCRH_WORD_LENGTH_8 0x60
#define LCRH_WORD_LENGTH_7 0x40
#define LCRH_WORD_LENGTH_6 0x20
#define LCRH_WORD_LENGTH_5 0x00
#define LCRH_FIFO_ENABLED 0x10
#define LCRH_2_STOP_BITS 0x08
#define LCRH_EVEN_PARITY 0x04
#define LCRH_PARITY_ENABLE 0x02
#define LCRH_SEND_BREAK 0x01
/*****************************************************************************/
/* Line Control Medium Byte Register - LCRM */
/* This register specifies the high byte of the Baud rate divisor */
/*****************************************************************************/
#define LCRM_BAUD_460800 0x00
#define LCRM_BAUD_230400 0x00
#define LCRM_BAUD_115200 0x00
#define LCRM_BAUD_76800 0x00
#define LCRM_BAUD_57600 0x00
#define LCRM_BAUD_38400 0x00
#define LCRM_BAUD_19200 0x00
#define LCRM_BAUD_14400 0x00
#define LCRM_BAUD_9600 0x00
#define LCRM_BAUD_2400 0x01
#define LCRM_BAUD_1200 0x02
/*****************************************************************************/
/* Line Control Low Byte Register - LCRL */
/* This register specifies the low byte of the Baud rate divisor */
/*****************************************************************************/
#define LCRL_BAUD_460800 0x01
#define LCRL_BAUD_230400 0x03
#define LCRL_BAUD_115200 0x07
#define LCRL_BAUD_76800 0x0B
#define LCRL_BAUD_57600 0x0F
#define LCRL_BAUD_38400 0xC
#define LCRL_BAUD_19200 0x2F
#define LCRL_BAUD_14400 0x3F
#define LCRL_BAUD_9600 0x5F
#define LCRL_BAUD_2400 0x7F
#define LCRL_BAUD_1200 0xFF
/*****************************************************************************/
/* Control Register - CR */
/*****************************************************************************/
#define CR_LOOP_BACK_EN 0x80
#define CR_TIMEOUT_INT_EN 0x40
#define CR_TX_INT_ENABLE 0x100
#define CR_RX_INT_ENABLE 0x200
#define CR_MODSTAT_INT_EN 0x08
#define CR_UART_ENABLE 0x01
/*****************************************************************************/
/* Flag Register - FR */
/*****************************************************************************/
#define FR_TX_FIFO_EMPTY 0x80
#define FR_RX_FIFO_FULL 0x40
#define FR_TX_FIFO_FULL 0x20
#define FR_RX_FIFO_EMPTY 0x10
#define FR_BUSY 0x08
#define FR_CARRIER_DETECT 0x04
#define FR_SET_READY 0x02
#define FR_CLEAR_TO_SEND 0x01
/*****************************************************************************/
/* Interrupt Identification Register - IIR */
/*****************************************************************************/
#define IIR_RX_TIME_OUT 0x08
#define IIR_TX 0x04
#define IIR_RX 0x02
#define IIR_MODEM 0x01
void UartStdOutInit(void) {
// Disable the serial port while setting the baud rate and word length
UART0_CR = 0;
// Clear the receive status register
UART0_ECR = 0;
// Set the correct baud rate and word length
UART0_LCRL = LCRL_BAUD_115200;
UART0_LCRM = LCRM_BAUD_115200;
UART0_LCRH = LCRH_WORD_LENGTH_8;
// Explicitly disable FIFO's for char mode
UART0_LCRH &= ~LCRH_FIFO_ENABLED;
// Enable UART0 (and RX/TX) without interrupts
UART0_CR = CR_UART_ENABLE | CR_TX_INT_ENABLE | CR_RX_INT_ENABLE;
}
unsigned char UartPutc(unsigned char ch) {
if (ch == '\n') {
(void)UartPutc('\r');
}
while (UART0_FR & FR_TX_FIFO_FULL)
;
UART0_DR = ch;
return ch;
}
unsigned char UartGetc(void) {
unsigned char c;
while (UART0_FR & FR_RX_FIFO_EMPTY)
;
c = UART0_DR;
if (c == '\r') {
c = '\n';
}
return c;
}
// Get line from terminal
unsigned int GetLine(char *lp, unsigned int len) {
unsigned int cnt = 0;
char c;
do {
c = UartGetc();
switch (c) {
case CNTLQ: /* ignore Control S/Q */
case CNTLS:
break;
case BACKSPACE:
case DEL:
if (cnt == 0) {
break;
}
cnt--; /* decrement count */
lp--; /* and line pointer */
UartPutc(0x08); /* echo backspace */
UartPutc(' ');
UartPutc(0x08);
fflush(stdout);
break;
case ESC:
case 0:
*lp = 0; /* ESC - stop editing line */
return 0;
case CR: /* CR - done, stop editing line */
*lp = c;
lp++; /* increment line pointer */
cnt++; /* and count */
c = LF;
UartPutc(*lp = c); /* echo and store character */
fflush(stdout);
lp++; /* increment line pointer */
cnt++; /* and count */
break;
default:
UartPutc(*lp = c); /* echo and store character */
fflush(stdout);
lp++; /* increment line pointer */
cnt++; /* and count */
break;
}
} while (cnt < len - 2 && c != LF); /* check limit and CR */
*lp = 0; /* mark end of string */
return 1;
}
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