tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * Copyright (c) 2016 IBM Corporation.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
8 */
9
10#include "ops.h"
11#include "stdio.h"
12#include "io.h"
13#include <libfdt.h>
14#include "../include/asm/opal-api.h"
15
16#ifdef CONFIG_PPC64_BOOT_WRAPPER
17
18/* Global OPAL struct used by opal-call.S */
19struct opal {
20 u64 base;
21 u64 entry;
22} opal;
23
24static u32 opal_con_id;
25
26/* see opal-wrappers.S */
27int64_t opal_console_write(int64_t term_number, u64 *length, const u8 *buffer);
28int64_t opal_console_read(int64_t term_number, uint64_t *length, u8 *buffer);
29int64_t opal_console_write_buffer_space(uint64_t term_number, uint64_t *length);
30int64_t opal_console_flush(uint64_t term_number);
31int64_t opal_poll_events(uint64_t *outstanding_event_mask);
32
33void opal_kentry(unsigned long fdt_addr, void *vmlinux_addr);
34
35static int opal_con_open(void)
36{
37 /*
38 * When OPAL loads the boot kernel it stashes the OPAL base and entry
39 * address in r8 and r9 so the kernel can use the OPAL console
40 * before unflattening the devicetree. While executing the wrapper will
41 * probably trash r8 and r9 so this kentry hook restores them before
42 * entering the decompressed kernel.
43 */
44 platform_ops.kentry = opal_kentry;
45 return 0;
46}
47
48static void opal_con_putc(unsigned char c)
49{
50 int64_t rc;
51 uint64_t olen, len;
52
53 do {
54 rc = opal_console_write_buffer_space(opal_con_id, &olen);
55 len = be64_to_cpu(olen);
56 if (rc)
57 return;
58 opal_poll_events(NULL);
59 } while (len < 1);
60
61
62 olen = cpu_to_be64(1);
63 opal_console_write(opal_con_id, &olen, &c);
64}
65
66static void opal_con_close(void)
67{
68 opal_console_flush(opal_con_id);
69}
70
71static void opal_init(void)
72{
73 void *opal_node;
74
75 opal_node = finddevice("/ibm,opal");
76 if (!opal_node)
77 return;
78 if (getprop(opal_node, "opal-base-address", &opal.base, sizeof(u64)) < 0)
79 return;
80 opal.base = be64_to_cpu(opal.base);
81 if (getprop(opal_node, "opal-entry-address", &opal.entry, sizeof(u64)) < 0)
82 return;
83 opal.entry = be64_to_cpu(opal.entry);
84}
85
86int opal_console_init(void *devp, struct serial_console_data *scdp)
87{
88 opal_init();
89
90 if (devp) {
91 int n = getprop(devp, "reg", &opal_con_id, sizeof(u32));
92 if (n != sizeof(u32))
93 return -1;
94 opal_con_id = be32_to_cpu(opal_con_id);
95 } else
96 opal_con_id = 0;
97
98 scdp->open = opal_con_open;
99 scdp->putc = opal_con_putc;
100 scdp->close = opal_con_close;
101
102 return 0;
103}
104#else
105int opal_console_init(void *devp, struct serial_console_data *scdp)
106{
107 return -1;
108}
109#endif /* __powerpc64__ */