| /* |
| * 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; |
| } |