1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (c) 2016 IBM Corporation.
4 */
5
6#include "ops.h"
7#include "stdio.h"
8#include "io.h"
9#include <libfdt.h>
10#include "../include/asm/opal-api.h"
11
12/* Global OPAL struct used by opal-call.S */
13struct opal {
14	u64 base;
15	u64 entry;
16} opal;
17
18static u32 opal_con_id;
19
20/* see opal-wrappers.S */
21int64_t opal_console_write(int64_t term_number, u64 *length, const u8 *buffer);
22int64_t opal_console_read(int64_t term_number, uint64_t *length, u8 *buffer);
23int64_t opal_console_write_buffer_space(uint64_t term_number, uint64_t *length);
24int64_t opal_console_flush(uint64_t term_number);
25int64_t opal_poll_events(uint64_t *outstanding_event_mask);
26
27void opal_kentry(unsigned long fdt_addr, void *vmlinux_addr);
28
29static int opal_con_open(void)
30{
31	/*
32	 * When OPAL loads the boot kernel it stashes the OPAL base and entry
33	 * address in r8 and r9 so the kernel can use the OPAL console
34	 * before unflattening the devicetree. While executing the wrapper will
35	 * probably trash r8 and r9 so this kentry hook restores them before
36	 * entering the decompressed kernel.
37	 */
38	platform_ops.kentry = opal_kentry;
39	return 0;
40}
41
42static void opal_con_putc(unsigned char c)
43{
44	int64_t rc;
45	uint64_t olen, len;
46
47	do {
48		rc = opal_console_write_buffer_space(opal_con_id, &olen);
49		len = be64_to_cpu(olen);
50		if (rc)
51			return;
52		opal_poll_events(NULL);
53	} while (len < 1);
54
55
56	olen = cpu_to_be64(1);
57	opal_console_write(opal_con_id, &olen, &c);
58}
59
60static void opal_con_close(void)
61{
62	opal_console_flush(opal_con_id);
63}
64
65static void opal_init(void)
66{
67	void *opal_node;
68
69	opal_node = finddevice("/ibm,opal");
70	if (!opal_node)
71		return;
72	if (getprop(opal_node, "opal-base-address", &opal.base, sizeof(u64)) < 0)
73		return;
74	opal.base = be64_to_cpu(opal.base);
75	if (getprop(opal_node, "opal-entry-address", &opal.entry, sizeof(u64)) < 0)
76		return;
77	opal.entry = be64_to_cpu(opal.entry);
78}
79
80int opal_console_init(void *devp, struct serial_console_data *scdp)
81{
82	opal_init();
83
84	if (devp) {
85		int n = getprop(devp, "reg", &opal_con_id, sizeof(u32));
86		if (n != sizeof(u32))
87			return -1;
88		opal_con_id = be32_to_cpu(opal_con_id);
89	} else
90		opal_con_id = 0;
91
92	scdp->open = opal_con_open;
93	scdp->putc = opal_con_putc;
94	scdp->close = opal_con_close;
95
96	return 0;
97}
98