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author | Michael Brown | 2005-03-08 19:53:11 +0100 |
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committer | Michael Brown | 2005-03-08 19:53:11 +0100 |
commit | 3d6123e69ab879c72ff489afc5bf93ef0b7a94ce (patch) | |
tree | 9f3277569153a550fa8d81ebd61bd88f266eb8da /src/core/serial.c | |
download | ipxe-3d6123e69ab879c72ff489afc5bf93ef0b7a94ce.tar.gz ipxe-3d6123e69ab879c72ff489afc5bf93ef0b7a94ce.tar.xz ipxe-3d6123e69ab879c72ff489afc5bf93ef0b7a94ce.zip |
Initial revision
Diffstat (limited to 'src/core/serial.c')
-rw-r--r-- | src/core/serial.c | 236 |
1 files changed, 236 insertions, 0 deletions
diff --git a/src/core/serial.c b/src/core/serial.c new file mode 100644 index 00000000..72207e8d --- /dev/null +++ b/src/core/serial.c @@ -0,0 +1,236 @@ +#include "etherboot.h" +#include "timer.h" +#ifdef CONSOLE_SERIAL + +/* + * The serial port interface routines implement a simple polled i/o + * interface to a standard serial port. Due to the space restrictions + * for the boot blocks, no BIOS support is used (since BIOS requires + * expensive real/protected mode switches), instead the rudimentary + * BIOS support is duplicated here. + * + * The base address and speed for the i/o port are passed from the + * Makefile in the COMCONSOLE and CONSPEED preprocessor macros. The + * line control parameters are currently hard-coded to 8 bits, no + * parity, 1 stop bit (8N1). This can be changed in init_serial(). + */ + +static int found = 0; + +#if defined(COMCONSOLE) +#undef UART_BASE +#define UART_BASE COMCONSOLE +#endif + +#ifndef UART_BASE +#error UART_BASE not defined +#endif + +#if defined(CONSPEED) +#undef UART_BAUD +#define UART_BAUD CONSPEED +#endif + +#ifndef UART_BAUD +#define UART_BAUD 115200 +#endif + +#if ((115200%UART_BAUD) != 0) +#error Bad ttys0 baud rate +#endif + +#define COMBRD (115200/UART_BAUD) + +/* Line Control Settings */ +#ifndef COMPARM +/* Set 8bit, 1 stop bit, no parity */ +#define COMPARM 0x03 +#endif + +#define UART_LCS COMPARM + +/* 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_LSR_TEMPT 0x40 /* Transmitter empty */ +#define UART_LSR_THRE 0x20 /* Transmit-hold-register empty */ +#define UART_LSR_BI 0x10 /* Break interrupt indicator */ +#define UART_LSR_FE 0x08 /* Frame error indicator */ +#define UART_LSR_PE 0x04 /* Parity error indicator */ +#define UART_LSR_OE 0x02 /* Overrun error indicator */ +#define UART_LSR_DR 0x01 /* Receiver data ready */ + +#define UART_MSR 0x06 +#define UART_SCR 0x07 + +#if defined(UART_MEM) +#define uart_readb(addr) readb((addr)) +#define uart_writeb(val,addr) writeb((val),(addr)) +#else +#define uart_readb(addr) inb((addr)) +#define uart_writeb(val,addr) outb((val),(addr)) +#endif + +/* + * void serial_putc(int ch); + * Write character `ch' to port UART_BASE. + */ +void serial_putc(int ch) +{ + int i; + int status; + if (!found) { + /* no serial interface */ + return; + } + i = 1000; /* timeout */ + while(--i > 0) { + status = uart_readb(UART_BASE + UART_LSR); + if (status & UART_LSR_THRE) { + /* TX buffer emtpy */ + uart_writeb(ch, UART_BASE + UART_TBR); + break; + } + mdelay(2); + } +} + +/* + * int serial_getc(void); + * Read a character from port UART_BASE. + */ +int serial_getc(void) +{ + int status; + int ch; + do { + status = uart_readb(UART_BASE + UART_LSR); + } while((status & 1) == 0); + ch = uart_readb(UART_BASE + UART_RBR); /* fetch (first) character */ + ch &= 0x7f; /* remove any parity bits we get */ + if (ch == 0x7f) { /* Make DEL... look like BS */ + ch = 0x08; + } + return ch; +} + +/* + * int serial_ischar(void); + * If there is a character in the input buffer of port UART_BASE, + * return nonzero; otherwise return 0. + */ +int serial_ischar(void) +{ + int status; + if (!found) + return 0; + status = uart_readb(UART_BASE + UART_LSR); /* line status reg; */ + return status & 1; /* rx char available */ +} + +/* + * int serial_init(void); + * Initialize port UART_BASE to speed CONSPEED, line settings 8N1. + */ +int serial_init(void) +{ + int initialized = 0; + int status; + int divisor, lcs; + + if (found) + return 1; + + divisor = COMBRD; + lcs = UART_LCS; + + +#ifdef COMPRESERVE + lcs = uart_readb(UART_BASE + UART_LCR) & 0x7f; + uart_writeb(0x80 | lcs, UART_BASE + UART_LCR); + divisor = (uart_readb(UART_BASE + UART_DLM) << 8) | uart_readb(UART_BASE + UART_DLL); + uart_writeb(lcs, UART_BASE + UART_LCR); +#endif + + /* Set Baud Rate Divisor to CONSPEED, and test to see if the + * serial port appears to be present. + */ + uart_writeb(0x80 | lcs, UART_BASE + UART_LCR); + uart_writeb(0xaa, UART_BASE + UART_DLL); + if (uart_readb(UART_BASE + UART_DLL) != 0xaa) + goto out; + uart_writeb(0x55, UART_BASE + UART_DLL); + if (uart_readb(UART_BASE + UART_DLL) != 0x55) + goto out; + uart_writeb(divisor & 0xff, UART_BASE + UART_DLL); + if (uart_readb(UART_BASE + UART_DLL) != (divisor & 0xff)) + goto out; + uart_writeb(0xaa, UART_BASE + UART_DLM); + if (uart_readb(UART_BASE + UART_DLM) != 0xaa) + goto out; + uart_writeb(0x55, UART_BASE + UART_DLM); + if (uart_readb(UART_BASE + UART_DLM) != 0x55) + goto out; + uart_writeb((divisor >> 8) & 0xff, UART_BASE + UART_DLM); + if (uart_readb(UART_BASE + UART_DLM) != ((divisor >> 8) & 0xff)) + goto out; + uart_writeb(lcs, UART_BASE + UART_LCR); + + /* disable interrupts */ + uart_writeb(0x0, UART_BASE + UART_IER); + + /* disable fifo's */ + uart_writeb(0x00, UART_BASE + UART_FCR); + + /* Set clear to send, so flow control works... */ + uart_writeb((1<<1), UART_BASE + UART_MCR); + + + /* Flush the input buffer. */ + do { + /* rx buffer reg + * throw away (unconditionally the first time) + */ + uart_readb(UART_BASE + UART_RBR); + /* line status reg */ + status = uart_readb(UART_BASE + UART_LSR); + } while(status & UART_LSR_DR); + initialized = 1; + out: + found = initialized; + return initialized; +} + +/* + * void serial_fini(void); + * Cleanup our use of the serial port, in particular flush the + * output buffer so we don't accidentially loose characters. + */ +void serial_fini(void) +{ + int i, status; + if (!found) { + /* no serial interface */ + return; + } + /* Flush the output buffer to avoid dropping characters, + * if we are reinitializing the serial port. + */ + i = 10000; /* timeout */ + do { + status = uart_readb(UART_BASE + UART_LSR); + } while((--i > 0) && !(status & UART_LSR_TEMPT)); +} +#endif |