xref: /linux/arch/parisc/kernel/pdc_cons.c (revision c532de5a67a70f8533d495f8f2aaa9a0491c3ad0)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *    PDC early console support - use PDC firmware to dump text via boot console
4  *
5  *    Copyright (C) 2001-2022 Helge Deller <deller@gmx.de>
6  */
7 
8 #include <linux/console.h>
9 #include <linux/init.h>
10 #include <linux/serial_core.h>
11 #include <linux/kgdb.h>
12 #include <asm/page.h>		/* for PAGE0 */
13 #include <asm/pdc.h>		/* for iodc_call() proto and friends */
14 
15 static void pdc_console_write(struct console *co, const char *s, unsigned count)
16 {
17 	int i = 0;
18 
19 	do {
20 		i += pdc_iodc_print(s + i, count - i);
21 	} while (i < count);
22 }
23 
24 #ifdef CONFIG_KGDB
25 static int kgdb_pdc_read_char(void)
26 {
27 	int c = pdc_iodc_getc();
28 
29 	return (c <= 0) ? NO_POLL_CHAR : c;
30 }
31 
32 static void kgdb_pdc_write_char(u8 chr)
33 {
34 	/* no need to print char as it's shown on standard console */
35 	/* pdc_iodc_print(&chr, 1); */
36 }
37 
38 static struct kgdb_io kgdb_pdc_io_ops = {
39 	.name = "kgdb_pdc",
40 	.read_char = kgdb_pdc_read_char,
41 	.write_char = kgdb_pdc_write_char,
42 };
43 #endif
44 
45 static int __init pdc_earlycon_setup(struct earlycon_device *device,
46 				     const char *opt)
47 {
48 	struct console *earlycon_console;
49 
50 	/* If the console is duplex then copy the COUT parameters to CIN. */
51 	if (PAGE0->mem_cons.cl_class == CL_DUPLEX)
52 		memcpy(&PAGE0->mem_kbd, &PAGE0->mem_cons, sizeof(PAGE0->mem_cons));
53 
54 	earlycon_console = device->con;
55 	earlycon_console->write = pdc_console_write;
56 	device->port.iotype = UPIO_MEM32BE;
57 
58 #ifdef CONFIG_KGDB
59 	kgdb_register_io_module(&kgdb_pdc_io_ops);
60 #endif
61 
62 	return 0;
63 }
64 
65 EARLYCON_DECLARE(pdc, pdc_earlycon_setup);
66