Eric Biederman | 8ca8d76 | 2003-04-22 19:02:15 +0000 | [diff] [blame] | 1 | /* Should support 8250, 16450, 16550, 16550A type uarts */ |
| 2 | #include <arch/io.h> |
| 3 | #include <uart8250.h> |
| 4 | |
| 5 | /* Data */ |
| 6 | #define UART_RBR 0x00 |
| 7 | #define UART_TBR 0x00 |
| 8 | |
| 9 | /* Control */ |
| 10 | #define UART_IER 0x01 |
| 11 | #define UART_IIR 0x02 |
| 12 | #define UART_FCR 0x02 |
| 13 | #define UART_LCR 0x03 |
| 14 | #define UART_MCR 0x04 |
| 15 | #define UART_DLL 0x00 |
| 16 | #define UART_DLM 0x01 |
| 17 | |
| 18 | /* Status */ |
| 19 | #define UART_LSR 0x05 |
| 20 | #define UART_MSR 0x06 |
| 21 | #define UART_SCR 0x07 |
| 22 | |
Greg Watson | e54d55b | 2004-03-13 03:40:51 +0000 | [diff] [blame^] | 23 | static int uart8250_can_tx_byte(unsigned base_port) |
Eric Biederman | 8ca8d76 | 2003-04-22 19:02:15 +0000 | [diff] [blame] | 24 | { |
| 25 | return inb(base_port + UART_LSR) & 0x20; |
| 26 | } |
| 27 | |
| 28 | static inline void uart8250_wait_to_tx_byte(unsigned base_port) |
| 29 | { |
| 30 | while(!uart8250_can_tx_byte(base_port)) |
| 31 | ; |
| 32 | } |
| 33 | |
| 34 | static inline void uart8250_wait_until_sent(unsigned base_port) |
| 35 | { |
| 36 | while(!(inb(base_port + UART_LSR) & 0x40)) |
| 37 | ; |
| 38 | } |
| 39 | |
| 40 | void uart8250_tx_byte(unsigned base_port, unsigned char data) |
| 41 | { |
| 42 | uart8250_wait_to_tx_byte(base_port); |
| 43 | outb(data, base_port + UART_TBR); |
| 44 | /* Make certain the data clears the fifos */ |
| 45 | uart8250_wait_until_sent(base_port); |
| 46 | } |
| 47 | |
Greg Watson | e54d55b | 2004-03-13 03:40:51 +0000 | [diff] [blame^] | 48 | int uart8250_can_rx_byte(unsigned base_port) |
| 49 | { |
| 50 | return inb(base_port + UART_LSR) & 0x01; |
| 51 | } |
| 52 | |
| 53 | unsigned char uart8250_rx_byte(unsigned base_port) |
| 54 | { |
| 55 | while(!uart8250_can_rx_byte(base_port)) |
| 56 | ; |
| 57 | return inb(base_port + UART_RBR); |
| 58 | } |
| 59 | |
Eric Biederman | 8ca8d76 | 2003-04-22 19:02:15 +0000 | [diff] [blame] | 60 | void uart8250_init(unsigned base_port, unsigned divisor, unsigned lcs) |
| 61 | { |
| 62 | lcs &= 0x7f; |
| 63 | /* disable interrupts */ |
| 64 | outb(0x0, base_port + UART_IER); |
| 65 | /* enable fifo's */ |
| 66 | outb(0x01, base_port + UART_FCR); |
| 67 | /* Set Baud Rate Divisor to 12 ==> 115200 Baud */ |
| 68 | outb(0x80 | lcs, base_port + UART_LCR); |
| 69 | outb(divisor & 0xFF, base_port + UART_DLL); |
| 70 | outb((divisor >> 8) & 0xFF, base_port + UART_DLM); |
| 71 | outb(lcs, base_port + UART_LCR); |
| 72 | } |
Eric Biederman | 5cd8173 | 2004-03-11 15:01:31 +0000 | [diff] [blame] | 73 | |
| 74 | /* Initialize a generic uart */ |
| 75 | void init_uart8250(unsigned base_port, struct uart8250 *uart) |
| 76 | { |
| 77 | int divisor; |
| 78 | int lcs; |
| 79 | divisor = 115200/(uart->baud ? uart->baud: 1); |
| 80 | lcs = 3; |
| 81 | if (base_port == TTYS0_BASE) { |
| 82 | /* Don't reinitialize the console serial port, |
| 83 | * This is espeically nasty in SMP. |
| 84 | */ |
| 85 | return; |
| 86 | } |
| 87 | uart8250_init(base_port, divisor, lcs); |
| 88 | } |