| /* |
| * Copyright 2018 Google LLC |
| * |
| * 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 |
| * |
| * https://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. |
| */ |
| |
| #include "hf/dlog.h" |
| |
| #include "io.h" |
| |
| /* UART Data Register. */ |
| #define UARTDR 0 |
| |
| /* UART Flag Register. */ |
| #define UARTFR 0x018 |
| |
| /* UART Flag Register bit: transmit fifo is full. */ |
| #define UARTFR_TXFF (1 << 5) |
| |
| /* UART Flag Register bit: UART is busy. */ |
| #define UARTFR_BUSY (1 << 3) |
| |
| void arch_putchar(char c) |
| { |
| /* Print a carriage-return as well. */ |
| if (c == '\n') { |
| arch_putchar('\r'); |
| } |
| |
| /* Wait until there is room in the tx buffer. */ |
| while (io_read(PL011_BASE + UARTFR) & UARTFR_TXFF) { |
| /* do nothing */ |
| } |
| |
| dmb(); |
| |
| /* Write the character out. */ |
| io_write(PL011_BASE + UARTDR, c); |
| |
| dmb(); |
| |
| /* Wait until the UART is no longer busy. */ |
| while (io_read_mb(PL011_BASE + UARTFR) & UARTFR_BUSY) { |
| /* do nothing */ |
| } |
| } |