forked from Minki/linux
027c3d345e
Rewrite the PDC console to become an early console. Beside the fact that now boot information is visible until another (text- or graphics) console takes over, this benefits as well machines with a yet-unsupported STI console and kgdb. Signed-off-by: Helge Deller <deller@gmx.de>
76 lines
1.8 KiB
C
76 lines
1.8 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* PDC early console support - use PDC firmware to dump text via boot console
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*
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* Copyright (C) 2001-2022 Helge Deller <deller@gmx.de>
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*/
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#include <linux/console.h>
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#include <linux/init.h>
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#include <linux/serial_core.h>
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#include <linux/kgdb.h>
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#include <asm/page.h> /* for PAGE0 */
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#include <asm/pdc.h> /* for iodc_call() proto and friends */
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static DEFINE_SPINLOCK(pdc_console_lock);
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static void pdc_console_write(struct console *co, const char *s, unsigned count)
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{
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int i = 0;
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unsigned long flags;
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spin_lock_irqsave(&pdc_console_lock, flags);
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do {
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i += pdc_iodc_print(s + i, count - i);
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} while (i < count);
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spin_unlock_irqrestore(&pdc_console_lock, flags);
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}
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#ifdef CONFIG_KGDB
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static int kgdb_pdc_read_char(void)
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{
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int c;
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unsigned long flags;
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spin_lock_irqsave(&pdc_console_lock, flags);
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c = pdc_iodc_getc();
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spin_unlock_irqrestore(&pdc_console_lock, flags);
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return (c <= 0) ? NO_POLL_CHAR : c;
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}
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static void kgdb_pdc_write_char(u8 chr)
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{
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if (PAGE0->mem_cons.cl_class != CL_DUPLEX)
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pdc_console_write(NULL, &chr, 1);
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}
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static struct kgdb_io kgdb_pdc_io_ops = {
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.name = "kgdb_pdc",
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.read_char = kgdb_pdc_read_char,
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.write_char = kgdb_pdc_write_char,
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};
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#endif
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static int __init pdc_earlycon_setup(struct earlycon_device *device,
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const char *opt)
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{
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struct console *earlycon_console;
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/* If the console is duplex then copy the COUT parameters to CIN. */
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if (PAGE0->mem_cons.cl_class == CL_DUPLEX)
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memcpy(&PAGE0->mem_kbd, &PAGE0->mem_cons, sizeof(PAGE0->mem_cons));
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earlycon_console = device->con;
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earlycon_console->write = pdc_console_write;
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device->port.iotype = UPIO_MEM32BE;
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#ifdef CONFIG_KGDB
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kgdb_register_io_module(&kgdb_pdc_io_ops);
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#endif
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return 0;
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}
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EARLYCON_DECLARE(pdc, pdc_earlycon_setup);
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