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 DEFINE_SPINLOCK(pdc_console_lock);
16
pdc_console_write(struct console * co,const char * s,unsigned count)17 static void pdc_console_write(struct console *co, const char *s, unsigned count)
18 {
19 int i = 0;
20 unsigned long flags;
21
22 spin_lock_irqsave(&pdc_console_lock, flags);
23 do {
24 i += pdc_iodc_print(s + i, count - i);
25 } while (i < count);
26 spin_unlock_irqrestore(&pdc_console_lock, flags);
27 }
28
29 #ifdef CONFIG_KGDB
kgdb_pdc_read_char(void)30 static int kgdb_pdc_read_char(void)
31 {
32 int c;
33 unsigned long flags;
34
35 spin_lock_irqsave(&pdc_console_lock, flags);
36 c = pdc_iodc_getc();
37 spin_unlock_irqrestore(&pdc_console_lock, flags);
38
39 return (c <= 0) ? NO_POLL_CHAR : c;
40 }
41
kgdb_pdc_write_char(u8 chr)42 static void kgdb_pdc_write_char(u8 chr)
43 {
44 if (PAGE0->mem_cons.cl_class != CL_DUPLEX)
45 pdc_console_write(NULL, &chr, 1);
46 }
47
48 static struct kgdb_io kgdb_pdc_io_ops = {
49 .name = "kgdb_pdc",
50 .read_char = kgdb_pdc_read_char,
51 .write_char = kgdb_pdc_write_char,
52 };
53 #endif
54
pdc_earlycon_setup(struct earlycon_device * device,const char * opt)55 static int __init pdc_earlycon_setup(struct earlycon_device *device,
56 const char *opt)
57 {
58 struct console *earlycon_console;
59
60 /* If the console is duplex then copy the COUT parameters to CIN. */
61 if (PAGE0->mem_cons.cl_class == CL_DUPLEX)
62 memcpy(&PAGE0->mem_kbd, &PAGE0->mem_cons, sizeof(PAGE0->mem_cons));
63
64 earlycon_console = device->con;
65 earlycon_console->write = pdc_console_write;
66 device->port.iotype = UPIO_MEM32BE;
67
68 #ifdef CONFIG_KGDB
69 kgdb_register_io_module(&kgdb_pdc_io_ops);
70 #endif
71
72 return 0;
73 }
74
75 EARLYCON_DECLARE(pdc, pdc_earlycon_setup);
76
