--- /dev/null
+/*
+ * 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().
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include "stddef.h"
+#include <ipxe/init.h>
+#include <ipxe/io.h>
+#include <unistd.h>
+#include <ipxe/serial.h>
+#include "config/serial.h"
+
+/* Set default values if none specified */
+
+#ifndef COMCONSOLE
+#define COMCONSOLE 0x3f8
+#endif
+
+#ifndef COMSPEED
+#define COMSPEED 9600
+#endif
+
+#ifndef COMDATA
+#define COMDATA 8
+#endif
+
+#ifndef COMPARITY
+#define COMPARITY 0
+#endif
+
+#ifndef COMSTOP
+#define COMSTOP 1
+#endif
+
+#undef UART_BASE
+#define UART_BASE ( COMCONSOLE )
+
+#undef UART_BAUD
+#define UART_BAUD ( COMSPEED )
+
+#if ((115200%UART_BAUD) != 0)
+#error Bad ttys0 baud rate
+#endif
+
+#define COMBRD (115200/UART_BAUD)
+
+/* Line Control Settings */
+#define UART_LCS ( ( ( (COMDATA) - 5 ) << 0 ) | \
+ ( ( (COMPARITY) ) << 3 ) | \
+ ( ( (COMSTOP) - 1 ) << 2 ) )
+
+/* 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
+
+/* Boolean for the state of serial driver initialization */
+int serial_initialized = 0;
+
+/*
+ * void serial_putc(int ch);
+ * Write character `ch' to port UART_BASE.
+ */
+void serial_putc ( int ch ) {
+ int i;
+ int status;
+ 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;
+ 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 COMSPEED, line settings 8N1.
+ */
+static void serial_init ( void ) {
+ int status;
+ int divisor, lcs;
+
+ DBG ( "Serial port %#x initialising\n", UART_BASE );
+
+ 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 COMSPEED, 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) {
+ DBG ( "Serial port %#x UART_DLL failed\n", UART_BASE );
+ goto out;
+ }
+ uart_writeb(0x55, UART_BASE + UART_DLL);
+ if (uart_readb(UART_BASE + UART_DLL) != 0x55) {
+ DBG ( "Serial port %#x UART_DLL failed\n", UART_BASE );
+ goto out;
+ }
+ uart_writeb(divisor & 0xff, UART_BASE + UART_DLL);
+ if (uart_readb(UART_BASE + UART_DLL) != (divisor & 0xff)) {
+ DBG ( "Serial port %#x UART_DLL failed\n", UART_BASE );
+ goto out;
+ }
+ uart_writeb(0xaa, UART_BASE + UART_DLM);
+ if (uart_readb(UART_BASE + UART_DLM) != 0xaa) {
+ DBG ( "Serial port %#x UART_DLM failed\n", UART_BASE );
+ goto out;
+ }
+ uart_writeb(0x55, UART_BASE + UART_DLM);
+ if (uart_readb(UART_BASE + UART_DLM) != 0x55) {
+ DBG ( "Serial port %#x UART_DLM failed\n", UART_BASE );
+ goto out;
+ }
+ uart_writeb((divisor >> 8) & 0xff, UART_BASE + UART_DLM);
+ if (uart_readb(UART_BASE + UART_DLM) != ((divisor >> 8) & 0xff)) {
+ DBG ( "Serial port %#x UART_DLM failed\n", UART_BASE );
+ goto out;
+ }
+ uart_writeb(lcs, UART_BASE + UART_LCR);
+
+ /* disable interrupts */
+ uart_writeb(0x0, UART_BASE + UART_IER);
+
+ /* enable fifos */
+ uart_writeb(0x01, 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)
+ */
+ (void) uart_readb(UART_BASE + UART_RBR);
+ /* line status reg */
+ status = uart_readb(UART_BASE + UART_LSR);
+ } while(status & UART_LSR_DR);
+
+ /* Note that serial support has been initialized */
+ serial_initialized = 1;
+ out:
+ return;
+}
+
+/*
+ * void serial_fini(void);
+ * Cleanup our use of the serial port, in particular flush the
+ * output buffer so we don't accidentially lose characters.
+ */
+static void serial_fini ( int flags __unused ) {
+ int i, status;
+ /* 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));
+ /* Don't mark it as disabled; it's still usable */
+}
+
+/**
+ * Serial driver initialisation function
+ *
+ * Initialise serial port early on so that it is available to capture
+ * early debug messages.
+ */
+struct init_fn serial_init_fn __init_fn ( INIT_SERIAL ) = {
+ .initialise = serial_init,
+};
+
+/** Serial driver startup function */
+struct startup_fn serial_startup_fn __startup_fn ( STARTUP_EARLY ) = {
+ .shutdown = serial_fini,
+};
Code Review / kvmfornfv.git / blobdiff