arch/parisc/kernel/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
  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);