pdc_cons.c

 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
15static 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
25static int kgdb_pdc_read_char(void)
26{
27	int c = pdc_iodc_getc();
28
29	return (c <= 0) ? NO_POLL_CHAR : c;
30}
31
32static 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
38static 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
45static 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
65EARLYCON_DECLARE(pdc, pdc_earlycon_setup);