7 #include <syslinux/config.h>
27 int serial_init(struct serial_if *sif, const char *argv[])
29 const struct syslinux_serial_console_info *sci
30 = syslinux_serial_console_info();
33 uint8_t dll, dlm, lcr;
39 printf("No port number specified and not using serial console!\n");
43 port = strtoul(argv[0], NULL, 0);
45 uint16_t addr = ((uint16_t *)0x400)[port];
47 printf("No serial port address found!\n");
50 printf("Serial port %u is at 0x%04x\n", port, addr);
58 divisor = 1; /* Default speed = 115200 bps */
60 /* Check to see if this is the same as the serial console */
61 if (port == sci->iobase) {
62 /* Overlaying the console... */
65 /* Default to already configured speed */
66 divisor = sci->divisor;
68 /* Shut down I/O to the console for the time being */
69 openconsole(&dev_null_r, &dev_null_w);
72 if (argv[0] && argv[1])
73 divisor = 115200/strtoul(argv[1], NULL, 0);
75 cli(); /* Just in case... */
77 /* Save old register settings */
78 sif->old.lcr = inb(port + LCR);
79 sif->old.mcr = inb(port + MCR);
80 sif->old.iir = inb(port + IIR);
83 outb(0x83, port + LCR); /* Enable divisor access */
84 sif->old.dll = inb(port + DLL);
85 sif->old.dlm = inb(port + DLM);
86 outb(divisor, port + DLL);
87 outb(divisor >> 8, port + DLM);
88 (void)inb(port + IER); /* Synchronize */
90 dll = inb(port + DLL);
91 dlm = inb(port + DLM);
92 lcr = inb(port + LCR);
93 outb(0x03, port + LCR); /* Enable data access, n81 */
94 (void)inb(port + IER); /* Synchronize */
95 sif->old.ier = inb(port + IER);
97 /* Disable interrupts */
102 if (dll != (uint8_t)divisor ||
103 dlm != (uint8_t)(divisor >> 8) ||
106 printf("No serial port detected!\n");
107 return -1; /* This doesn't look like a serial port */
110 /* Enable 16550A FIFOs if available */
111 outb(0x01, port + FCR); /* Enable FIFO */
112 (void)inb(port + IER); /* Synchronize */
113 if (inb(port + IIR) < 0xc0)
114 outb(0x00, port + FCR); /* Disable FIFOs if non-functional */
115 (void)inb(port + IER); /* Synchronize */
120 void serial_write(struct serial_if *sif, const void *data, size_t n)
122 uint16_t port = sif->port;
123 const char *p = data;
128 lsr = inb(port + LSR);
129 } while (!(lsr & 0x20));
131 outb(*p++, port + THR);
135 void serial_read(struct serial_if *sif, void *data, size_t n)
137 uint16_t port = sif->port;
143 lsr = inb(port + LSR);
144 } while (!(lsr & 0x01));
146 *p++ = inb(port + RBR);
150 void serial_cleanup(struct serial_if *sif)
152 uint16_t port = sif->port;
154 outb(0x83, port + LCR);
155 (void)inb(port + IER);
156 outb(sif->old.dll, port + DLL);
157 outb(sif->old.dlm, port + DLM);
158 (void)inb(port + IER);
159 outb(sif->old.lcr & 0x7f, port + LCR);
160 (void)inb(port + IER);
161 outb(sif->old.mcr, port + MCR);
162 outb(sif->old.ier, port + IER);
163 if (sif->old.iir < 0xc0)
164 outb(0x00, port + FCR); /* Disable FIFOs */
166 /* Re-enable console messages, if we shut them down */
168 openconsole(&dev_null_r, &dev_stdcon_w);