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Merge pull request #15 from MerryMage/uart

UART
This commit is contained in:
SciresM 2018-02-22 14:18:09 -08:00 committed by GitHub
commit c032bd812c
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2 changed files with 68 additions and 0 deletions

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exosphere/uart.c Normal file
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#include "uart.h"
volatile void *g_uart_registers = NULL;
void set_uart_address(void *uart_base) {
g_uart_registers = uart_base;
}
inline void *get_uart_address(void) {
return g_uart_registers;
}
void uart_initialize(uint16_t divider) {
/* Setup UART in 16450 mode. We assume the relevant UART clock has been enabled. */
/* Disable FIFO */
UART_IIR_FCR_0 = 0x00;
/* Set DLAB */
UART_LCR_0 = 0x80;
UART_THR_DLAB_0_0 = (uint8_t)divider;
UART_IER_DLAB_0_0 = (uint8_t)(divider >> 8);
/* 8N1 mode */
UART_LCR_0 = 0x03;
}
void uart_transmit_char(char ch) {
/* Wait for THR to be empty */
while (!(UART_LSR_0 & 0x20)) {}
UART_THR_DLAB_0_0 = ch;
}
void uart_transmit_str(const char *str) {
while (*str) {
uart_transmit_char(*str++);
}
}
void uart_transmit_hex(uint32_t value) {
for (unsigned int i = 0; i < 8; i++) {
uint32_t nibble = (value >> (28 - i * 4)) & 0xF;
uart_transmit_char("0123456789ABCDEF"[nibble]);
}
}

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exosphere/uart.h Normal file
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#ifndef EXOSPHERE_UART_H
#define EXOSPHERE_UART_H
#include <stdint.h>
/* Exosphere driver for the Tegra X1 UARTs. */
void set_uart_address(void *uart_base);
void *get_uart_address(void); /* This is inlined in uart.c */
#define UART_THR_DLAB_0_0 (*((volatile uint32_t *)(get_uart_address() + 0x0)))
#define UART_IER_DLAB_0_0 (*((volatile uint32_t *)(get_uart_address() + 0x4)))
#define UART_IIR_FCR_0 (*((volatile uint32_t *)(get_uart_address() + 0x8)))
#define UART_LCR_0 (*((volatile uint32_t *)(get_uart_address() + 0xC)))
#define UART_LSR_0 (*((volatile uint32_t *)(get_uart_address() + 0x14)))
void uart_initialize(uint16_t divider);
void uart_transmit_char(char ch);
void uart_transmit_str(const char *str);
void uart_transmit_hex(uint32_t value);
#endif