| /* Should support 8250, 16450, 16550, 16550A type uarts */ |
| #include <arch/io.h> |
| #include <uart8250.h> |
| |
| /* Data */ |
| #define UART_RBR 0x00 |
| #define UART_TBR 0x00 |
| |
| /* Control */ |
| #define UART_IER 0x01 |
| #define UART_IIR 0x02 |
| #define UART_FCR 0x02 |
| #define UART_LCR 0x03 |
| #define UART_MCR 0x04 |
| #define UART_DLL 0x00 |
| #define UART_DLM 0x01 |
| |
| /* Status */ |
| #define UART_LSR 0x05 |
| #define UART_MSR 0x06 |
| #define UART_SCR 0x07 |
| |
| static inline int uart8250_can_tx_byte(unsigned base_port) |
| { |
| return inb(base_port + UART_LSR) & 0x20; |
| } |
| |
| static inline void uart8250_wait_to_tx_byte(unsigned base_port) |
| { |
| while(!uart8250_can_tx_byte(base_port)) |
| ; |
| } |
| |
| static inline void uart8250_wait_until_sent(unsigned base_port) |
| { |
| while(!(inb(base_port + UART_LSR) & 0x40)) |
| ; |
| } |
| |
| void uart8250_tx_byte(unsigned base_port, unsigned char data) |
| { |
| uart8250_wait_to_tx_byte(base_port); |
| outb(data, base_port + UART_TBR); |
| /* Make certain the data clears the fifos */ |
| uart8250_wait_until_sent(base_port); |
| } |
| |
| int uart8250_can_rx_byte(unsigned base_port) |
| { |
| return inb(base_port + UART_LSR) & 0x01; |
| } |
| |
| unsigned char uart8250_rx_byte(unsigned base_port) |
| { |
| while(!uart8250_can_rx_byte(base_port)) |
| ; |
| return inb(base_port + UART_RBR); |
| } |
| |
| void uart8250_init(unsigned base_port, unsigned divisor, unsigned lcs) |
| { |
| lcs &= 0x7f; |
| /* disable interrupts */ |
| outb(0x0, base_port + UART_IER); |
| /* enable fifo's */ |
| outb(0x01, base_port + UART_FCR); |
| /* assert DTR and RTS so the other end is happy */ |
| outb(0x03, base_port + UART_MCR); |
| /* Set Baud Rate Divisor to 12 ==> 115200 Baud */ |
| outb(0x80 | lcs, base_port + UART_LCR); |
| outb(divisor & 0xFF, base_port + UART_DLL); |
| outb((divisor >> 8) & 0xFF, base_port + UART_DLM); |
| outb(lcs, base_port + UART_LCR); |
| } |
| |
| /* Initialize a generic uart */ |
| void init_uart8250(unsigned base_port, struct uart8250 *uart) |
| { |
| int divisor; |
| int lcs; |
| divisor = 115200/(uart->baud ? uart->baud: 1); |
| lcs = 3; |
| if (base_port == TTYS0_BASE) { |
| /* Don't reinitialize the console serial port, |
| * This is espeically nasty in SMP. |
| */ |
| return; |
| } |
| uart8250_init(base_port, divisor, lcs); |
| } |