1 /* 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2020 Vijai Kumar K <vijai@behindbytes.com> 5 */ 6 7 #include <sbi/riscv_io.h> 8 #include <sbi/sbi_console.h> 9 #include <sbi_utils/serial/shakti-uart.h> 10 11 #define REG_BAUD 0x00 12 #define REG_TX 0x04 13 #define REG_RX 0x08 14 #define REG_STATUS 0x0C 15 #define REG_DELAY 0x10 16 #define REG_CONTROL 0x14 17 #define REG_INT_EN 0x18 18 #define REG_IQ_CYCLES 0x1C 19 #define REG_RX_THRES 0x20 20 21 #define UART_TX_FULL 0x2 22 #define UART_RX_FULL 0x8 23 24 static volatile void *uart_base; 25 shakti_uart_putc(char ch)26void shakti_uart_putc(char ch) 27 { 28 while((readw(uart_base + REG_STATUS) & UART_TX_FULL)) 29 ; 30 writeb(ch, uart_base + REG_TX); 31 } 32 shakti_uart_getc(void)33int shakti_uart_getc(void) 34 { 35 u16 status = readw(uart_base + REG_STATUS); 36 if (status & UART_RX_FULL) 37 return readb(uart_base + REG_RX); 38 return -1; 39 } 40 shakti_uart_init(unsigned long base,u32 in_freq,u32 baudrate)41int shakti_uart_init(unsigned long base, u32 in_freq, u32 baudrate) 42 { 43 uart_base = (volatile void *)base; 44 u16 baud = (u16)(in_freq/(16 * baudrate)); 45 writew(baud, uart_base + REG_BAUD); 46 47 return 0; 48 } 49